Symposium CA

ABSTRACTS

Session CA-1 Advances in powder synthesis and processing

CA-1:IL01 From Droplet Evolution to Activity: Process–Structure–Property Design via Glatt Powder Synthesis
J. BUCHHEIM, V. DRESCHER, T. VOCKENBERG, Glatt Ingenieurtechnik Gmbh, Weimar, Germany

High-performance functional ceramics require tightly controlled powder attributes—from stoichiometry and phase purity to morphology and surface chemistry. We present a continuous Glatt Powder Synthesis (GPS) that couples solution-to-powder conversion with rapid thermal treatment in a controlled hot-gas environment. Decoupled control over droplet formation, reaction kinetics, and residence time enables homogeneous doping, narrow size distributions, and hierarchical porosity without energy-intensive post-processing. Applications include (i) OER-active doped ferrites (MFe₂O₄; Ni/Co/Fe spinels such as NiFe₂O₄, CoFe₂O₄ with A/B-site substitutions) featuring tailored defect chemistry and high SSA; (ii) perovskite electrode powders for SOFC/SOEC such as LSM (La₁₋ₓSrₓMnO₃±δ) and LSCF (La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃₋δ) with tunable grain size, sinterability, and mixed conductivity; and (iii) solid electrolytes GDC (Ce₁₋ₓGdₓO₂₋δ, e.g., Ce₀.₉Gd₀.₁O₁.₉₅) and YSZ with tight phase control and high densification. We elaborate process–structure–property links, scale-up, and manufacturing integration, highlighting GPS as a bridge from lab recipes to industrial production.

CA-1:IL02  Synthesis of Aerogels as Functional Ceramics: Routes to Improved Thermal Stability
J.A. KROGSTAD, University of Illinois Urbana Champaign, Urbana, IL, USA

For lightweight, thermal insulation needs above 1000ºC, the high surface to volume ratios of ceramic-based aerogels are practically unparalleled. Yet realizing the full potential of aerogel-based thermal protection systems requires not only increased thermal stability, but also a broadened menu of stabilizing mechanisms. Here we will review our recent efforts to understand the impact of synthetic parameters and dopant chemistry on the evolution of zirconia-based ceramics. A broad parametric window for thermal stability is established, in which the more sensitive variable of composition has been probed. However, dopant chemistry is actually an aggregate for many closely related material parameters including surface energy, enthalpy of formation, each of which may contribute uniquely to aerogel destabilization. This design landscape expands further when we begin to explore multilayered or coated architectures. Ultimately, a truly predictive design framework for ceramic-based aerogels that links structural stability to thermal, mechanical and even optical performance, requires further decoupling of these underlying properties through systematic and comprehensive evaluation of thermodynamic properties.

CA-1:L03  Application of Radiation-Thermal Sintering of Deposited Functional Layers of Structured Catalysts, Membranes and Solid Oxide Fuel Cells
Y. BESPALKO¹, N. EREMEEV¹, O. BULAVCHENKO¹, E. SUPRUN, M. MIKHAILENKO², M. KOROBEYNIKOV³, V. SADYKOV¹, ¹Federal Research Center Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia; ²Institute of Solid State Chemistry and Mechanochemistry SB RAS, Novosibirsk, Russia; ³Budker Institute of Nuclear Physics SB RAS, Novosibirsk, Russia

Currently, technologies for processing functional materials with unique characteristics are being intensively developed. In addition to traditional sintering in an oven, modern sintering methods such as microwave, laser, hot pressing, etc. are used to produce durable ceramics used in the energy industry. The main problem of manufacturing such ceramics using traditional sintering in an oven is the need for long-term sintering at high temperatures. An alternative method is radiation-thermal sintering, which significantly reduces the temperature and processing time due to the interaction of electron beams and solid materials, such as energy dissipation and the effect of radiation-stimulated diffusion. A technology for deposition of functional ceramic layers using electron beam heating has been developed. The following research objects were selected (lanthanide tungstates/molybdates and their nanocomposites with nickel alloys, lanthanide scandates, bismuth titanates and cerates, lanthanide layered nickelates). Optimal technologies for processing various materials with electron beams with varying media and conditions (heating speed and duration, processing temperatures) have been developed. During radiation-thermal sintering using electron beams, the energy consumption for obtaining dense ceramics and deposited functional layers is reduced several times compared with traditional sintering methods.
The work was supported by the Russian Science Foundation (Project 23-73-00045).

CA-1:L04  Alternative Methods for the Calibration of the Drucker-Prager/Cap Model, Application to the MOX Fuel Shaping
B. SPANU¹, T. REBILLON¹, J. P. BAYLE¹, A. SOCIÉ², T. HELFER², G. BERNARD-GRANGER¹, ¹CEA, DES, ISEC, DMRC, Univ. Montpellier, Marcoule, France; ²CEA, DES, IRESNE, DEC, Saint-Paul-lez-Durance, France

Uniaxial cold pressing is the standard method for shaping UO₂/PuO₂ Mixed OXide (MOX) nuclear fuel pellets. This process takes place between powder milling and green compact sintering. During compaction, the stress and density gradients generated by this manufacturing step partially determine the final quality of the sintered fuel, particularly its mechanical strength and dimensional accuracy. Finite Element Modelling (FEM) is employed here to investigate the influence of powder characteristics, tooling (punches and die geometry), and the pressing cycle (kinematics and amplitude) on the mechanical behaviour of MOX powder. The powder is modelled using a porous elastoplastic Drucker-Prager/Cap (DPC) constitutive law. This presentation focuses on the experimental calibration of the DPC law for various PuO₂ mass fractions. FEM simulations are then used for calculation-test correlation to validate both the numerical approach and the identified DPC parameters. Given the nature of the material (nuclear oxides), this study proposes a dedicated methodology to minimize the number of required experimental tests.

CA-1:L05  Application of the Heterocoagulation Phenomenon in Reactive Sintering of MgAl₂O₄ and Production of MgAl₂O₄- Al₂O₃ Composites
O. JURECKA, K. KORNAUS, Ł. ZYCH, AGH University of Krakow, Faculty of Materials Science and Ceramics, Department of Ceramics and Refractories, Kraków, Poland

The heterocoagulation phenomenon is a key innovation in obtaining of advanced ceramic materials, which facilitates a precise connection of particles possessing dissimilar chemical nature which in turn yields a more homogenous phase distribution and a significant reduction in microstructural defects. Furthermore, careful control of polyelectrolytes addition allows for wider modification of a particle surface charge, thereby expanding a range of compatible materials combinations and enhancing stability and quality of resulting suspensions. A heterocoagulation mechanism is evaluated during the formation of MgAl₂O₄ in Al₂O₃–MgO system by the reactive sintering. The same approach is applied to produce composites based on Al₂O₃ reinforced with MgAl₂O₄. Zeta potential measurements were used to assess the heterocoagulation during preparation of water suspensions of MgO and Al₂O₃ powders. The zeta potential of the powders was adjusted by polyectrolyte addition and pH control. The suspensions were formed by a filter pressing method, and the resulting materials were free sintered. The phase composition of the sintered bodies was evaluated (XRD) and their microstructure was observed using SEM. Uniformity of the microstructure was evaluated using quantitative image analysis methods.

CA-1:IL06 Sintering Investigations of UO2 and MOX Formulations: Mechanisms and Microstructure
G. BERNARD-GRANGER, CEA/DES/ISEC/DMRC/SPTC/LSEM & Université de Montpellier Centre de Marcoule, Bagnols sur Cèze, France

Sintering investigations on UO2 and MOX fuel pellets have been completed. Various parameters were studied: the method of preparing the granular medium before shaping the pellets by uniaxial pressing, the heating rate, the isothermal holding temperature, the duration of the isothermal holding and the oxygen potential of the sintering atmosphere. Sintering maps (evolution of grain size as a function of relative density) were built. The apparent activation energies for densification were calculated using various methods and the mechanisms controlling densification and grain growth were proposed. Finally, statistical tests were performed to characterize the potential difference in grain size between the core and the periphery of the sintered pellets as a function of the sintering conditions.

CA-1:IL07  Multiscale Microstructure Control of Ceramics Using Powder Assembly Techniques
HIROYUKI MUTO, Toyohashi University of Technology, Institute of Liberal Arts and Sciences, Department of Electrical and Electronics Information Engineering, Institute for Research on Next Generation Semiconductor and Sensing Science, Toyohashi, Japan

The functionality of ceramics and their composites is strongly intercorrelated with the composition and distribution of their constituent materials. Therefore, precise control of starting powders is crucial for fabricating ceramics with desired properties. While nanoscale materials possess unique and often superior characteristics compared to their bulk counterparts, achieving controlled dispersion and scalable integration remains a major challenge. In this talk, I present a practical, bottom-up strategy for large-scale fabrication of multiscale ceramics using the electrostatic integrated powder assembly technique. This approach enables controlled incorporation of additive materials in the form of composite particles or granules, exhibiting desired architectures and homogeneity. I will also share our recent findings which demonstrate the feasibility of tailoring multiscale ceramic microstructures through electrostatically assembled powders, offering a promising route toward the design and scalable fabrication of advanced functional ceramics.

CA-1:L08  Computational Modeling of Cold Press Compaction in B4C Ceramic Powder
M.C. ŞİMŞEK, K. KAYA, Ş. RAKICI, M.B. ÜNAL, H.H. TÜRKMEN, Oğulbey Mah., Ankara, Türkiye

Achieving a uniform density distribution during compaction is both challenging and essential for the cold pressing of ceramic powders. Density gradients in a pressed boron carbide (B4C) powder compact cause differential shrinkage during sintering, leading to defects and inferior terminal ballistic performance. In this work, a custom instrumented uniaxial pressing setup was used to characterize the compaction behavior of B4C powder. Load–displacement data were collected under different loads, enabling evaluation of the powder’s compressibility (pressure–density response), stiffness, and green strength at multiple compaction levels. These data were used to calibrate LS-DYNA©’s *MAT_271_POWDER model for B4C powder via a curve-fitting optimization with LS-OPT©. The calibrated model was then applied to simulate cold pressing of B4C armor plates, predicting density fields and stress distributions within the compacts. Finally, the numerical simulations were used to optimize the powder deposition pattern to minimize density gradients. Overall, this integrated experimental–computational approach provides a framework to optimize cold pressing parameters and tooling, improving the uniformity, and thereby enhancing the performance of B4C ceramic armor.

CA-1:L09  CuO-TiO2-Nb2O5 Sintering Aid for Reducing Sintering Temperature of Alumina and Zirconia Ceramics
R. SHAKIRZYANOV, N. VOLODINA, YU. GARANIN, K. KALIYEKPEROVA, A. KOZLOVSKIY, L.N. Gumilyov Eurasian National University, Astana, Kazakhstan; The Institute of Nuclear Physics, Almaty, Kazakhstan

Al2O3 and ZrO2 ceramics combine low cost with excellent mechanical, thermal and chemical characteristics, making them useful in a wide range of applications, including refractory materials, electrical insulators, wear-resistant industrial components, and biocompatible materials. However, the production of high-density ceramics usually requires sintering temperatures of 1500 ℃ or higher. To reduce processing temperature, sintering aids are often used. In this work, a 4CuO-TiO2-2Nb2O5 sintering additive was proposed, as it is known to promote liquid-phase sintering and enhance diffusion between ceramic components. The introduction of the sintering additive into the charge resulted in ceramics, reaching nearly theoretical density when sintered at 1300 ℃ for alumina and at 1100 ℃ for zirconia. The addition of the 4CuO-TiO2-2Nb2O5 also led to noticeable improvements in the mechanical properties of the ceramics. Furthermore, this additive affected dielectric characteristics of alumina and zirconia ceramics in distinct ways. In alumina ceramics, it led to a pronounced increase in low-frequency permittivity (2–500 Hz) up to 562, whereas in zirconia ceramics, it resulted in low-loss dielectric behavior with a stable permittivity of ~ 20 over a wide temperature range.

CA-1:L10 Optimizing Iron Removal from Fly Ashes of Varying Compositions for Use in Ceramic Applications
S. SHADDEL, C.C. SORRELL, P. KOSHY, School of Materials Science and Engineering, University of New South Wales, Sydney, NSW, Australia

Fly ash is a major by-product of coal combustion in power plants, posing both a considerable environmental challenge and an industrial waste issue, while also being a valuable resource with potential applications in agriculture, construction, and geopolymers. Fly ash is an aluminosilicate-rich material containing significant amounts of SiO₂ and Al₂O₃, which form the chemical basis of many ceramic systems. However, the presence of iron-bearing impurities such as Fe₂O₃ limits its use in high-value ceramic applications due to undesirable coloration and phase interactions. This study examines acid leaching with sulfuric, nitric, and hydrochloric acids for iron removal from fly ashes with different calcium contents. The objective was to determine optimal leaching conditions and evaluate the influence of acid type on efficiency. Parameters such as acid concentration, reaction time, temperature, and solid-to-liquid ratio were systematically assessed. Results indicate that calcium content significantly affects iron removal. Higher acid concentration, longer reaction time, and elevated temperature improved extraction until stable optimum values were reached, while a lower solid-to-liquid ratio further enhanced removal.

CA-1:IL11  Colloidal Approach to the Additive Manufacturing of Cemented Carbides
A. MARTINEZ-BARJA, B. FERRARI, A. FERRANDEZ, A.J. SANCHEZ-HERENCIA, Institute for Ceramic and Glass, Madrid, Spain

Additive manufacturing (AM) of cemented carbides, such as tungsten carbide (WC) or Titanium carbonitrides is difficult to achieve by power-bed techniques that requires of a high-energy heat source, like a laser or electron beam. Like in most of the ceramic materials, the processing by AM techniques has been faced by the so-called indirect techniques that involve two or more steps to fabricate a green part with as high packing density as possible. The colloidal approach addresses these by creating stable suspensions with controlled zeta potential, optimized dispersants and high solid loading. This ensures uniform particle packing and rheology suitable for shaping by different material extrusion techniques. Among that the Fused Filament Fabrication (FFF) leverages these formulations to produce highly loaded filaments, enabling extrusion of complex geometries with dimensional accuracy. The selection of the adequate particle sizes distribution together to the small additions of metallic sintering aids, such as Ni, enhance densification in the filament and during sintering without compromising phase stability. Post-processing involves careful debinding and sintering under controlled atmospheres to minimize grain growth and maintain mechanical integrity.

CA-1:IL12  Different Powder Technology Routes for TZP Ceramics with Multiple Stabilizers
F. KERN, B. OSSWALD, University of Stuttgart, IKMT, Stuttgart, Germany

Manufacturing of TZP ceramics with multiple stabilizers offer the opportunity to tailor the mechanical properties. Commercially available powders are typically single stabilizer powders using either yttria or ceria and recently also calcia as stabilizers, Co-stabilized powders from such precursors can be obtained by mixing and milling processes. Hence, introducing stabilizers from a broader portfolio of rare earth elements requires a suitable synthesis route such as co-milling of monoclinic zirconia and stabilizer oxides or a wet chemical "coating" route with subsequent phase formation by solid state reaction during sintering. In both co-milling and "coating" routes the stabilizers are incorporated gradually during sintering. This leads to stabilizer gradients and an inhomogeneous core-shell structure in the grains which is progressively eliminated with increasing temperature and time. TZPs retaining a core shell structure are extremely tough and ageing resistant as they contain an unstabilized yet tetragonal core and an extremely overstabilized shell. TZPs with of up to 6 different stabilizers were tested which offer exceptional combinations of strength and toughness, higher stability against overfiring compared to single stabilizer TZP and transformation induced plasticity.

CA-1:L13  Synthesis of Monodispersed ZrC Nanoparticles Derived from MOF-801
YUN ZOU, H.J. LEE, S.H. LEE, Korea Institute of Materials Science, Changwon, Republic of Korea

Zirconium carbide (ZrC), an ultrahigh temperature ceramic (UHTC), combines a high melting point, strength, and thermal conductivity, making it suitable for extreme environments. Conventional carbothermal reduction of ZrO2 requires high temperature and long duration, often yielding coarse, irregular ZrC powders that hinder densification. To overcome this, novel synthesis strategies enabling control over particle size and morphology are essential. MOF-801, a Zr-based metal–organic framework, provides uniform Zr dispersion and molecular-level carbon incorporation, reducing diffusion distance and synthesis temperature. In this study, monodisperse ZrC nanoparticles were prepared via carbothermal reduction using MOF-801 and sucrose as precursors. The effects of sucrose content, temperature, and holding time on ZrC particles were investigated. Nanosized ZrC powders (100–150 nm) were obtained at 1500 °C, and their sintering behavior was further discussed.

CA-1:L14  Mechanical Destabilization Drives Thermally-activated Phase Transformation in Layered MAX Phases
B. RATZKER^1,2, O. MESSER², M. SOKOL², ¹Max Planck Institute for Sustainable Materials, Düsseldorf, Germany; ²Tel Aviv University, Israel

Mechanical milling is widely used to refine or mix powders to influence the sintering and microstructures of consolidated materials, yet its impact on the intrinsic stability of layered materials remains largely unexplored. Here, we show that high-energy ball milling of Ti3AlC2 drives the material into a metastable, defect-rich state that fundamentally alters its thermally-activated phase evolution. This defect-driven destabilization facilitates solid-state transformation pathways, leading to the formation of TiCx and Al2O3 during subsequent thermal treatment. We demonstrate that this transformation is triggered by the outward diffusion and surface oxidation of Al, while coherent TiCx laths form in-situ within the MAX phase grains. By exploiting this mechanically induced metastability, we establish a processing route to produce dense Al2O3/TiCx/Ti3AlC2 ceramic nanocomposites with a refined microstructure, enhanced hardness (13 GPa), and high fracture toughness (7.6 MPa·m1/2). These findings provide a mechanistic framework for defect-driven transformations in layered materials, where controlled mechanical activation becomes a design tool for tailoring microstructure and properties.

CA-1:L15  Understanding the Sintering of MOX Nuclear Fuels: Challenges Associated with the Characterization of a Multiphasic Microstructure
E. MOREL, F. LEBRETON, L. GAUTHIER, L. RAMOND, G. BERNARD-GRANGER, CEA, DES, ISEC, DMRC, Univ Montpellier, Marcoule, France; G. CUNHA COSTA MIRANDA, T. GENEVES, ORANO MELOX, Chusclan, France

MOX (Mixed oxide) nuclear fuels for Light Water Reactors are U-Pu oxide ceramic pellets. At the industrial scale, they are manufactured by a two-step powder mixing from PuO₂ and UO₂ powders, uniaxial pressing and sintering at 1700°C under a reductive atmosphere, yielding a heterogeneous three-phase microstructure (Pu-rich agglomerates, U-rich agglomerates, coating phase) and porosity with specific morphologies depending on their location in the microstructure. To address such peculiar microstructures, dedicated characterization routines were developed, combining experimental techniques and computational image analysis. This enables simultaneous phase-based grain size measurement while redefining phase segmentation using a single instrument, reducing acquisition time and eliminating dataset alignment. Pore clustering based on their morphologies was also investigated through unsupervised learning algorithms. These insights will feed simulations and models to predict MOX sintering behavior, reducing reliance on nuclear material experiments. This tandem of experimental and computational approaches advances the understanding of MOX process/microstructure/property relation and paves the way for future fabrication-characterization work.

CA-1:L16  Enhanced Alumina Sintering Via Electrostatically Assembled Alumina Composite Particles
WAI KIAN TAN, KATSUMI FUJISHIRO, GO KAWAMURA, ATSUNORI MATSUDA, HIROYUKI MUTO, Toyohashi University of Technology, Toyohashi, Aichi, Japan

Powder metallurgy offers a scalable and cost-effective route for fabricating ceramic materials, where sintering plays a crucial role in achieving densification. Effective sintering requires uniform mixing and controlled temperature to prevent defects caused by inhomogeneous additive distribution. In this study, bimodal alumina powders comprising coarse and fine particles were used. To overcome agglomeration and mixing limitations inherent to mechanical blending, electrostatic assembly was employed to fabricate alumina–alumina composite particles with a homogeneous distribution of fine particles on coarse particle surfaces. The sinterability of these composites was systematically examined as a function of additive content and sintering temperature. Enhanced densification and microstructural uniformity were achieved compared with conventionally mixed powders. Findings from this study demonstrate that electrostatically assembled composite particles enable efficient pressureless sintering, offering a promising approach for energy-efficient ceramic fabrication.

CA-1:L17  Structural and Optical Evolution of BaCuSi₄O₁₀ and BaCuSi₂O₆ Obtained through a Scalable, Cost-Effective Precipitation Process
M. BALAYAN, A. ISAHAKYAN, A. TERZYAN, H. BEGLARYAN, Institute of General and Inorganic Chemistry of the NAS RA, Yerevan, Armenia; Yerevan State University, Yerevan, Armenia

BaCuSi₄O₁₀ and BaCuSi₂O₆, historically known as Chinese Blue and Chinese Purple, were and are valued for their vivid color and stability. Recently, the latter has drawn interest as a quasi-two-dimensional quantum magnet exhibiting field-induced magnon condensation. Both materials exhibit intense near-infrared luminescence suitable for security inks, optical coatings, and bioimaging. A simplified cost-effective precipitation method was used for the first time to obtain these compounds under mild conditions, reducing reaction temperature and avoiding toxic lead fluxes typically used in solid-state approaches. Compared to other methods, such as hydrothermal, TEOS-based, or solution-combustion routes, precipitation avoids complex precursors and long treatments. Silicates obtained via this method show high crystallinity, phase purity, and uniform morphology. Structural and optical studies confirmed the color stability and PL performance of the synthesized products, showing the competitiveness with those made by conventional approaches. Additional tests across glazes, epoxy resins, and oils show excellent dispersion and durability. The developed route offers a sustainable and scalable approach to high-performance Ba–Cu silicates for optical and ceramic applications.
The research was supported by the Higher Education and Science Committee of MESCS RA (Research project № 24LCG-1D017).

Session CA-2 Advanced molecular-level processing of functional nanomaterials

CA-2:IL18  Direct Coating and Patterning of Nano-Structured Ceramic Materials in/from Solution via Soft, Solution Processing
MASAHIRO YOSHIMURA, Prof. Emeritus Tokyo Institute of Technology, presently KISTEC, Kanagawa, Japan; Former Distinguished Chair Professor, Dept of Mater.,Sci. and Eng., National Cheng Kung University, Tainan, Taiwan

Modern materials with desired shape, size, location have generally been fabricated by so-called high-technology, where high temperature, high pressure, vacuum, and highly energetic species like molecule, atom, ion, plasma, etc., in a particular chamber with limited volume have been used. Even they need multi-step processes. They consume huge amount of resources and energies thus exhausted huge amounts of wastes: matters and heats = entropy. Considering reduction of total energy usages and wastes, we have challenged to fabricate Films and Patterns of advanced materials directly in low energetic routes using aqueous solutions. Since 1995 an innovative concept and technology, “Soft Processing” or “Soft, Solution Processing,” which aims low energetic (=environmentally friendly) fabrication of shaped, sized, located, and oriented inorganic materials in/from solutionshave been proposed. It can be regarded as a green processing, or an eco-processing. We have succeeded to fabricate films then patterns of BaTiO3 and SrTiO3(1989-90) on Ti, LiCoO2 on Pt, then CaWO4, CdS, and PbS on Papers, thenTiO2 and CeO2 on glass by ink-jet reactions. We succeeded directl-patterning of ceramic films in solution without any firing, masking nor etching. Direct Patterning of carbon patterns on Si by plasma using a needle electrode in solutions. Successes in TiO2, ZrO2 and Al2O3 patterns by Ink-Jet Deposition, where nano-particles are nucleated and grown successively on the Si will be presented.A recent novel subject, Soft Processing for various nano-carbons including Graphene, functionalized Graphene and Mxene will be introduced. Where we have succeeded to prepare functionalized Graphene InkIn addition we propose Heat cascades for Materials Fabrication to eliminate wastes (Heat and materials=Entropy),we have combined Polymer Complex [PC] methods to maintain homogeneous solution.

CA-2:IL19  Automated Flow Reactors for the Controlled Synthesis of Functional Materials
J. DE MELLO, Norwegian Open Laboratory for High Throughput Experimentation and Scale-Up Norwegian University of Science and Technology, Trondheim, Norway

The controlled and reproducible production of high quality functional materials is of paramount importance in numerous areas of science and technology. In this presentation I will describe how flow chemistry can offer a versatile and scalable approach to synthesising a broad range of functional materials, and how it can deliver significant improvements in control compared to conventional flask-based methods. I will focus in particular on the use of automation methods in flow chemistry and on the design of “intelligent” reactors that are capable of automatically optimising the yield or properties of a target product. I will conclude by introducing NorHTE, "the Norwegian Open Laboratory for High Throughput Experimentation and Scale-Up", a new openly accessible infrastructure for the discovery and production of advanced materials.

CA-2:IL20  Transition-Metal Ceramic Electrocatalysts with Bifunctional Activity for Aqueous Zinc-Air Batteries
J. GONZÁLEZ-MORALES¹, M. APARICIO¹, J. MOSA¹, ¹Instituto de Cerámica y Vidrio (ICV-CSIC), Madrid, Spain

The growing demand for sustainable and efficient energy storage solutions calls for the development of robust and earth-abundant electrocatalysts capable of driving key oxygen reactions. Aqueous Zn–O₂ batteries, with higher energy densities than Li-ion systems, represent a promising alternative for large-scale and heavy-transport applications, yet their performance is limited by poor cyclability and dependence on noble metals such as Pt. Here, we present binder-free ceramic electrocatalysts based on transition metals (Fe, Ti, Mn, Ta), composed of mixed oxides, oxynitrides, and carbides, synthesized via a surfactant-assisted sol–gel route under ammonia flow. The nanostructured materials exhibit high surface area, controlled porosity, and excellent adhesion to Ni foam, enabling efficient bifunctional activity toward both oxygen reduction (ORR) and oxygen evolution (OER) reactions. Electrochemical tests reveal high catalytic efficiency, durability, and reversible performance, highlighting the potential of these transition-metal ceramics as a versatile and sustainable platform for next-generation Zn–air batteries and related electrochemical energy devices.

Session CA-3 Polymer-derived ceramics

CA-3:IL21  Engineering the Unmeltable: The Rise of Polymer-derived Ceramics for Extreme Environments
R. RIEDEL, Technical University of Darmstadt, Darmstadt, Germany

Polymer-derived ceramics (PDCs) have emerged as a powerful class of materials for next-generation high-temperature applications, offering unique opportunities for tailoring composition, microstructure, and functionality at multiple scales. Through the chemical modification of Si-based preceramic polymers and their controlled pyrolytic transformation, lightweight ceramics and composites with exceptional oxidation and ablation resistance can be achieved. This contribution highlights recent advances in the molecular design and processing of PDCs for the fabrication of ultrahigh-temperature protective coatings and C/C composites. Emphasis is placed on understanding how precursor chemistry and crosslinking behavior influence ceramic yield, phase evolution, and microstructural integrity under extreme thermal conditions. Advanced characterization, combined with multivariate data analysis, provides insights into the mechanisms that govern degradation, oxidation kinetics, and interfacial stability. Together, these findings demonstrate how PDC-based design strategies enable the development of “unmeltable” materials that combine structural robustness with functional adaptability — paving the way toward resilient ceramic systems for aerospace, energy, and defense applications.

CA-3:IL22  Ceramic Matrix Nanocomposites from Tailor-made Preceramic Polymers
S. BERNARD, CNRS, IRCER, UMR 7315, Univ. Limoges, Limoges, France

Hydrogen (H2) is considered as a promising energy carrier to assure the needs of humanity. Its combustion in a fuel cell (FC) emits only water and does not involve any noise pollution. However, in order to be used inside a FC, H2 needs to be at a very high level of purity, which can be achieved by using anion exchange membrane electrolysers allowing the use of non-noble transition metals in the composition of catalysts for hydrogen (HER) and oxygen (OER) evolution reactions in alkaline media. However, their nanoscale synthesis is highly challenging to limit the overpotential. The PDC (Polymer Derived Ceramics) route is a non-conventional way of designing ceramics by using preceramic polymers as precursors. The coordination (or direct reaction) of these precursors with metal complexes via the functional groups and/or ligands of the polymer makes it possible to trap transition metal carbide or nitride nanoparticles in a micro-/macroporous PDC matrix upon pyrolysis at low temperature. This will be the content of this presentation that will introduce our very recent works on this topic.

CA-3:IL23  Generation of Polymer-derived Ceramic Coatings on Light Metals via Laser Treatment
G. MOTZ, S. SCHAFFÖNER, A. HORCHER, University of Bayreuth, Ceramic Materials Engineering (CME), Bayreuth, Germany; K. TANGERMANN-GERK, Bayerisches Laserzentrum GmbH, Erlangen, Germany

The polymer-derived ceramic (PDC) technology is a versatile and cost-effective method for the preparation of ceramic coatings for various applications, as thermal barrier coatings, with high diffusion stability, hardness and wear resistance. However, the high temperatures required for the ceramization of the precursors limits this processing to substrates with high temperature stability. Thus, the laser pyrolysis has been proposed as alternative method to the conventional pyrolysis in a furnace. In this method, the irradiation of a laser beam is the energy source for the ceramization of the coatings, while the temperature of the substrate should remain low. Therefore, a coating system for aluminum and magnesium substrates was developed, consisting of an inorganic polysilazane bond-coat and a hard top-coat composed of an organosilazane with tetragonal ZrO2 and aluminum fillers ceramized using Nd:YVO4 laser. The laser irradiation led to pyrolysis of the silazane and to a dendritic microstructure of the coating, indicating complete melting of all fillers without damage of the substrate. The laser-treated coating system with a thickness up to 30 µm exhibited excellent adhesion to both substrates even under bending load and thermal cycling, nearly no cracks and high hardness.

CA-3:IL24  Polymer-derived Amorphous Silicon Nitride-Based Nanocomposites
YUJI IWAMOTO, Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan

Ceramic processing methods based on molecular engineering and precursor chemistry are well appropriate approaches to design novel functional materials that can reach performances beyond those developed by conventional synthesis routes. A very convenient precursor route is the Polymer-Derived Ceramics (PDCs) route which allows a precise chemical composition control of final materials from amorphous to polycrystalline state, especially non-oxide ceramic systems as well as their phase distribution and structure at nano- to micro-meter scale level. This paper presents our recent research work on the synthesis and characterization of PDCs, especially focused on amorphous silicon nitride-based composites such as SiAlN and Na-doped SiBN amorphous compounds which exhibit unique hydrogen chemisorption/desorption properties, and transition metal or antiperovskite nitride nanocrystallites-dispersed amorphous silicon nitrides. High-temperature CO2 chemisorption properties and catalytic activities for CO2 hydrogenation of the polymer-derived amorphous silicon nitride-based nanocomposites will be shown and discussed based on a comprehensive set of characterization techniques including DRIFTS and CO2-TPD analyses combined with the theoretical study by employing the DFT calculations.

CA-3:IL25  Polymer-derived Ceramics as Thermal and Environmental Barrier Coatings
N.-C. PETRY, M.C. GALETZ, DECHEMA research institute, Frankfurt, Germany; A.S. ULRICH, Metals and Alloys II, University of Bayreuth, Bayreuth, Germany; M. LEPPLE, Institute of Inorganic and Analytical Chemistry, Justus Liebig University Giessen, Giessen, Germany

Polymer-derived ceramics (PDCs) are a promising material class for use as thermal and/or environmental barrier coatings which are used as a protective layer on structural metallic or ceramic components in harsh conditions. PDCs are suitable for this purpose as they can be chemically modified, e. g. with metalorganic compounds, to form finely dispersed ultra-high temperature ceramic (UHTC) precipitates, forming nanocomposites (PDC-NCs). Si-based PDCs form a silica scale that may be protective against further corrosion in oxidizing atmospheres. PDCs show a versatile processability as the polymeric precursors are liquid or can be dissolved in organic solvents, which allows the usage of common polymer deposition techniques. This also allows high-temperature stable and/or corrosion stable filler particles to be introduced into the PDC matrix to further optimize the behavior. In this work different protection concepts are investigated. The focus of the study is the oxidation behavior, depending on the chemical modification and the microstructure. Differently modified PDCs such as PDC-NCs with UHTC ((Hf,Ta)C) nanoprecipitates or PDC as sinter additive for UHTC (ZrB2) are investigated as bulk materials. In addition, the protective effect of a coating of Al-modified PDC on Cr is studied.

CA-3:L26  Synthesis, Constituents, and Processing Technologies for UHTCMCs
J.H. DELCAMP, L. RUESCHHOFF, Z. APOSTOLOV, M.B. DICKERSON, T.L. PRUYN, Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH, USA

Uncertainty in the performance of high-temperature structural materials remains a challenge to their development and implementation in extreme environments. Materials in these applications are often exposed to high heat-fluxes resulting in very high temperatures, steep temperature gradients, oxidation, and erosion. Ultra-high temperature ceramics (UHTCs; e.g., refractory carbides and borides) are being considered for these applications due to their high temperature capability and high thermal conductivity. However, UHTCs are prone to oxidation under flight conditions and have low fracture toughness, which increases the risk of using them in demanding structural applications. One way to mitigate these challenges is to utilize these UHTCs in a ceramic matrix composite (CMC), but challenges arise in the fabrication of a UHTC matrix in a CMC. This presentation will focus on our work in addressing these challenges via the synthesis of novel UHTC polymeric precursors, incorporating UHTCs in fiber reinforced composites, and improving our understanding of oxidation behavior via validation under relevant conditions. While the ultimate goal is to improve the extreme-environment performance of ultra-high temperature CMCs, the intermediate targets are the ability to control the content.

CA-3:L27  Ultraviolet Curing of Polysilazane-based Coating System with Metallic Fillers
J.-F. WENDEL, A. FISCHER, S. SCHAFFÖNER, G. MOTZ, Chair of Ceramic Materials Engineering, University of Bayreuth, Bayreuth, Bavaria, Germany; D. LEYKAM, Chair of Electrochemical Process Engineering, University of Bayreuth, Bayreuth, Bavaria, Germany

As components become more complex and demanding in terms of performance, the requirements on coatings also increase. In order to meet these requirements and to produce coatings in a flexible and resource-efficient way, curing processes must also be further developed. Polymer-derived ceramic coatings which have excellent properties for many applications are usually thermally cured. However, thermal curing is not always applicable due to limitations imposed e.g. by constrained furnace size and the thermal sensitivity of many substrate materials. Curing using ultraviolet (UV) radiation is an alternative to avoid thermal stress. The feasibility of UV curing of preceramic polymers has already been demonstrated. However, many coating systems contain various fillers that may influence the curing process through reflection or absorption of UV radiation. Therefore, in this work the feasibility of UV curing for highly filled polysilazane-based coating systems with metallic fillers was demonstrated. A radical cross-linking reaction was performed using thiol-ene click chemistry with a tetra-functional thiol crosslinking agent and a photoinitiator. Thermally and UV-cured coatings were compared in terms of their mechanical and chemical properties, and the mechanism of UV curing was investigated.

Session CA-4 Microwave processing

CA-4:IL28  Microwave Synthesis of MAX Phases and Beyond
V. JOSHI, C.S. BIRKEL, Arizona State University, Tempe, AZ, USA

Microwave-assisted heating offers a rapid, energy-efficient, and sustainable route for synthesizing a wide range of inorganic solid materials, including oxides, chalcogenides, carbides, nitrides, and intermetallics. The method relies on direct coupling between microwave radiation and precursor species: when the precursors efficiently absorb electromagnetic energy, they undergo rapid temperature increase, enabling solid-state reactions to proceed significantly faster than under conventional radiative heating. This presentation will highlight the synthesis of layered solids such as MAX phase carbides and oxides via microwave heating. To elucidate their formation pathways, we have developed an in situ setup that records Raman spectra during both microwave and conventional heating. These real-time data, complemented by ex situ X-ray diffraction and electron microscopy analyses, provide comprehensive insights into the evolving structure and morphology. In addition to structural characterization, we investigate the magnetic and electrochemical properties of the resulting materials.

CA-4:IL29  Microwave-assisted Catalysis Constructed at the Atomic Scale
FUMINAO KISHIMOTO, The University of Tokyo, Tokyo, Japan

To advance green transformation (GX) in the chemical industry, electrification of chemical reactors using renewable energy is essential to reduce CO₂ emissions. Among electric heating methods, microwave irradiation has gained significant attention. Microwaves penetrate dielectric, magnetic, or conductive materials, generating internal heat and enabling selective, rapid heating unattainable by conventional methods. When applied to solid catalysts containing conductive ions or local dipole moments, microwaves can locally supply thermal energy at the atomic or molecular level, forming new catalytic reaction fields. Zeolites, though poor microwave absorbers, can host metal cations or polar molecules within their micropores, thereby concentrating microwave energy locally at the atomic scale. Our research group has demonstrated various catalytic reactions using zeolites containing metal cations selectively excited by microwaves. This presentation outlines design principles of zeolite materials suitable for microwave heating and introduces their applications to methane oxidation and CO₂ hydrogenation, highlighting future prospects for integrating zeolite science with microwave chemistry.

CA-4:IL30  Microwave-assisted Chemical Vapor Infiltration of SiCf/SiC Composites: State-of-the-art and Recent Developments
R. D’AMBROSIO¹, A. CINTIO¹, A. LAZZERI^1,2, G. ANNINO¹, ¹Istituto per i Processi Chimico-Fisici, IPCF-CNR, Pisa, Italy; ²Department of Civil and Industrial Engineering, University of Pisa, Pisa, Italy

The widespread use of Silicon Carbide fiber-reinforced Silicon Carbide Ceramic Matrix Composites (SiCf/SiC CMCs) is limited by high processing costs and long manufacturing times (up to 1000 h). The Microwave-assisted Chemical Vapor Infiltration (MW-CVI) process offers a promising alternative, in which the dielectric absorption of SiCf/SiC enables a selective volumetric heating, with infiltration temperatures of 900–1000°C reached within minutes. Moreover, it allows tailored temperature profiles that control the SiC matrix densification front, prevent the premature pores occlusion, and reduce the processing times by nearly an order of magnitude (~100 h). An innovative MW-CVI pilot plant was developed, featuring a multiport-multifrequency excitation scheme powered by three 2 kW Solid-State Generators operating across the 2.4–2.5 GHz ISM band. Its advanced electromagnetic design overcomes typical lab-scale limitations of MW heating, enabling for a quite uniform processing of large, industrially relevant CMC components. Ongoing research focuses on higher efficiency and localized densification processes, exploiting lower-frequency (470–860 MHz) Solid-State amplifier systems. The state-of-the-art and the recent developments of these technologies will be reviewed and discussed.

CA-4:L31  Pressure-assisted Microwave Sintering of Lead Free Piezoelectric Ceramics
A. ONFROY, C. MANIERE, S. MARINEL, Université Caen Normandie, ENSICAEN, CNRS, Normandie Univ, CRISMAT UMR6508, Caen, France

In response to the restrictions on lead use imposed by the European WEEE and RoHS directives, research has focused on lead-free piezoelectric materials. Among these, potassium sodium niobate (KNN), whose (K₀.₅,Na₀.₅)NbO₃ composition lies near the morphotropic phase boundary, exhibits electromechanical properties close to those of PZT. Due to the low sinterability of KNN and the volatility of alkali elements at high temperatures, achieving high-density ceramics by conventional sintering is limitted. Advanced techniques such as hot pressing (HP) or spark plasma sintering (SPS) enable densification at lower temperatures under applied pressure. However, vacuum SPS often induces reduction in KNN, requiring a post-sintering annealing step to restore stoichiometry. Pressure-assisted microwave sintering under air offers an alternative to SPS by enabling densification of KNN without the need for a post-sintering annealing step while minimizing alkali volatilization. This works consists of synthesis, sintering and characterization of KNN. The use of pressure assisted microwave cavity under air has allowed the densification of KNN ceramics. The dielectric and piezoelectric properties of the sintered KNN ceramics are discussed in relation to their microstructures and sintering conditions.

Session CA-5 Novel sintering approaches - Spark Plasma, Flash Sintering, Laser Sintering, Cold Sintering

CA-5:IL32  Cold Sintering of Functional Materials and Control of Grain Boundaries
C.A. RANDALL, Materials Research Institute, Department of Material Science and Engineering The Pennsylvania State University, University Park, PA, USA

Cold Sintering involves a transient chemical phase that permits the densification of particulate materials at low temperatures, 300 oC and below, under moderate pressures. The basic science of this process is related to a chemomechanical process known as pressure solution creep. The fundamental evidence for this process and the analysis of the rate limiting kinetics of this phenomena will be outlined. The cold sintering will be analyzed with isothermal and anisothermal approaches. The different mechanisms will be assessed with approaches that are inspired from dielectric relaxation approaches, from which energetics and mechanisms will be considered with respect to different chemistries. From an applied perspective, sintering at such low temperature offers many new technological opportunities. Therefore, cold sinter enables a platform for better unification of material science. Now ceramics, metal and polymers materials can be integrated under a common one-step process. Polymers, gels, and nanoparticles can be dispersed, interconnected and sintered in the grain boundaries of a ceramic matrix phase.

CA-5:IL33  In Situ Analysis of Solid-liquid Interfaces during Cold Sintering Process through Impedance Spectroscopy
T. HERISSON DE BEAUVOIR, E. SANCHEZ, A. KORBI, N. ALBAR, C. ESTOURNÈS, CIRIMAT, Université de Toulouse, Toulouse INP, CNRS, Toulouse cedex, France

New concerns about the composition/nature/behavior of grain boundaries (GB) emerged, different than what is usually observed in high temperature solid-state diffusion sintering techniques. This leads to widely affected properties of sintered materials, and is of huge importance in the case of electroceramics, sensitive to GB properties. To better control this aspect, a first step is to highlight and track these GBs evolutions. An in situ impedance analysis, during the sintering process of ceramics, was developed and used to measure the evolution of electronic/ionic conductivity of GB and liquid phase present in the process [3] (see the figure below, on the relationship between change in impedance during dwell time and schematic evolution of solid-liquid mixture during CSP]). Applying this to various ceramic materials allowed to shed light on unique GB evolution phenomena, but also highlighted the role and behavior of liquid phases used during sintering. The use of ionic liquids, often used for materials facing incongruent dissolution, was also explored and will be presented. The discussion will focus on the major trends, lessons learned from the use of in operando impedance analyses during CSP, offering opportunities to widely tune the properties of electroceramics.

CA-5:IL34  Cold Sintering of Electroceramics: Road to Solution or Troubles?
M. OTONIČAR^1,2, M. LACHHAB^1,2, A. ABASS SHAH¹, A. LALAGUE-DARDANT^1,3, S. SALMANOV¹, D. KUŠČER^1,2, B. MALIČ^1,2, ¹Jožef Stefan Institute, Electronic ceramics department, Ljubljana, Slovenia; ²Jožef Stefan International postgraduate school, Ljubljana, Slovenia; ³GREMAN laboratory, University of Tours, Blois, France

Since its discovery in 2016, the cold sintering process has been used to produce a variety of oxide and polymer materials with the aim of reducing energy input in materials production, or increasing densification if not achievable by conventional sintering methods. Limited cold-sintering studies were done on electroceramics thus far, with good functional responses not always attainable. The reasons are often low crystallinity of particles, limited perovskite-lattice solubility, inhibited grain growth and secondary phase precipitation. Therefore, understanding cold-sintered ferroelectric materials at the level of processing – structure – properties interplay is crucial for their further development. We studied the cold sintering process of several ferroelectrics, i.e., BiFeO3, K0.5Na0.5NbO3, and BaTiO3-based compositions. Cold sintering brings unique structural features into the perovskites, which include etched and curved grain-boundary contacts, crystal-lattice defects, dynamically-stable open-pore-channel frameworks, and changed oxidation states, among others. These structural peculiarities may lead to modified functional properties like high dielectric breakdown strength, polarization wake-up effect, biased polarization and strain loops, and electrically conductive samples.

CA-5:IL35  Very High Heating Rate during Ceramic Sintering vs Conventionnal Sintering: Influence on Microstructure and Properties
C. ESTOURNÈS¹, T. HERISSON DE BEAUVOIR¹, E. MARTIN¹, L. KARACASULU², G. CHEVALLIER¹, A. WEIBEL¹, C. MANIÈRE³, M. BIESUZ², ¹CIRIMAT, Université de Toulouse, Toulouse INP, CNRS, Toulouse cedex, France; ²University of Trento, Department of Industrial Engineering, Trento, Italy; ³Université Caen Normandie, ENSICAEN, CNRS, Normandie Univ, CRISMAT UMR6508, Caen, France

Technical ceramics play a key role across many sectors, including energy, biomedical, and transportation industries such as automotive, aerospace, and space. Growing demand for energy-efficient and eco-friendly production has driven research into low-temperature and ultra-fast sintering, leading to the creation of new materials and composites for diverse socio-economic applications. In this presentation, we will focus exclusively on the development of ultra-fast processes that enable the sintering of ceramics within just a few seconds. First, a brief overview of several such techniques will be provided, including Flash Sintering (FS), Blacklight Sintering (BS), Ultra-Fast High-Temperature Sintering (UHS), and Flash Spark Plasma Sintering (FSPS). A short review of the current understanding of the mechanisms involved in rapid sintering will also be presented. The main part of the talk will be devoted to the rapid sintering of yttria-stabilized zirconia using FSPS and UHS. The mechanical properties of the resulting nanoceramics will be discussed in relation to their structures and microstructures, and compared with those obtained through conventional sintering and/or classical SPS.

CA-5:IL36  Fabrication of Transparent Oxide Ceramics by Spark-Plasma-Sintering
KOJI MORITA, National Institute for Materials Science (NIMS), Research Center for Electronic and Optical Materials, Polycrystalline Optical Material Group, Tsukuba, Japan

Infrared (IR) transparent ceramics are important components for IR sensing and light emitting technologies. Although several IR transparent ceramics have been reported, those mechanical properties are not high enough to utilize in industrial applications. In order to improve the mechanical and optical properties simultaneously, reducing the grain size is recognized as an effective approach. Among the sintering techniques, spark plasma sintering (SPS) has been expected as a promising sintering technique that can realize fine grained and dense microstructures. This is because first, the SPS technique can attain high heating rate, and hence, can suppress the grain coarsening by reducing the processing time. Second, it has been explained that since the applied pulsed electric current can accelerate sinterability though the current effect in the SPS processing is still unclear. These characteristics of the SPS technique can achieve fine-grained and dense materials. By utilizing the SPS technique, we have succeeded to fabricate several IR transparent composite ceramics, which can simultaneously achieved good optical and mechanical properties.
This work was supported by Innovative Science and Technology Initiative for Security Grant Number JPJ004596, ATLA, Japan.

CA-5:IL37  Scale-bridging Processing of Advanced Ceramics
D. GIUNTINI, Eindhoven University of Technology, Eindhoven, Netherlands

Scientists and engineers dealing with materials typically think along the lines of the “Materials Science Tetrahedron”: how a material is processed determines its structure, which in turn controls its properties, ultimately defining performance. So it is common practice to carefully define processing routes that yield the structures one wishes for. But with the current blooming of sophisticated multiscale material architectures, enabling all sorts of exciting functionalities, how can processing keep up? And especially in ceramics, for which processing options are already so limited, how can we foster such exquisite nano- and micro-features in tangible, serviceable macro-scale objects? Multidisciplinarity can come to the rescue. By blending branches of chemistry, nanotechnology, optimization and mechanics, new and creative ceramics processing strategies can be envisioned. We show here how the recent advancements in colloidal assembly, additive manufacturing and ultrafast sintering are key enablers, especially with the support of process modeling. The simultaneous control of the material evolution at the nano-, micro- and macro-scale is enabled, unlocking tremendous potential for the development of hierarchical ceramics with tailorable mechanical and functional properties.

CA-5:L39  Fabrication of Boron-Rich Boron Carbide Ceramics (B₁₀C) by Hybrid High-Energy Ball Milling and Reactive SPS
N. KESHTKAR, J. LOPEZ-ARENAL, B. MALMAL MOSHTAGHIOUN, D. GOMEZ-GARCÍA, Departamento de Física de la Materia Condensada, Universidad de Sevilla, Sevilla, Spain

Boron carbide, a unique and highly multifunction ceramic material, presents a stoichiometric range extending from B₁₀C to B₄C, corresponding to a carbon content between 8.9 and 20 at%, respectively. In this work, a combination of high-energy ball milling of B + C powder mixtures followed by reactive spark plasma sintering (SPS) is proposed for the synthesis of boron-rich boron carbide monolithic ceramics with controlled stoichiometry. Firstly, it is demonstrated that both 1 hour and 10 hours of high-energy ball milling effectively refine the powders to the nanoscale, enhance their mechanical reactivity, and promote a homogeneous dispersion of B and C elements, thereby significantly improving the sinterability of the mixture, especially in case of 10 h milling. Secondly, a reaction between boron and carbon is shown to occur during the SPS process at an optimal temperature of 1700 ºC, leading to the formation of fully dense ceramics with a fine microstructure. Thirdly, Rietveld refinement of the XRD patterns confirms that the desired B₁₀C stoichiometry is achieved. Finally, the ceramic demonstrates a remarkable super-hard nature that is considerable higher in case of 10 h milling, attributed to its finely twinned grain microstructure that provides an efficient hardening mechanism.

CA-5:L40  Behavior of a C/UHTC Composite under Oxy-Acetylene Torch: In-Situ Analysis
F. TRAD¹, J. SEYMOUR¹, T. BOURDEAU¹, J. BRAUN², G. COUÉGNAT¹, F. REBILLAT¹, L. MAILLÉ¹, ¹Laboratoire des Composites ThermoStructuraux, UMR 5801 - CNRS - CEA - Safran - Université de Bordeaux, Pessac, France; ²CEA, DAM Le Ripault, Monts, France

Ultra-high-temperature ceramics (UHTCs) such as ZrB₂–ZrC–SiC composites are promising candidates for thermal protection of hypersonic vehicles operating above 2000 °C. However, their behavior remains poorly understood due to the complexity of oxidation, ablation, and cracking mechanisms, and the limitations of traditional post-mortem analyses. This project builds on the work of T. Bourdeau, who demonstrated the feasibility of coupling an oxy-acetylene torch (OAT) with synchrotron tomography to monitor in 3D and in real time the internal evolution of materials under high thermal flux. We propose to apply this approach to a ZrB₂–ZrC–SiC composite, optimized for its thermal conductivity, mechanical stability, and protective silica-forming ability. The novelty lies in the dynamic tomographic analysis of the flame incidence angle—a key parameter identified by C. Liégaut. The materials, developed by SPS flash sintering within the ANR COMEFAI project, will be tested at LCTS and at the synchrotron under controlled thermal conditions. Complementary tests using a robotic HVOF torch at LERMPS will broaden the experimental scope. The goal is to deepen our understanding of high-temperature ablation, oxidation, and protective layer formation mechanisms for aerospace applications.

CA-5:IL41  Low-temperature Chemical Densification of Ceramic Membranes for Electrochemical Devices
YUKI YAMAGUCHI, National Institute of Advance Industrial Science and Technology (AIST), Nagoya, Japan

Most ceramic materials undergo a process called 'sintering', whereby they are fired at temperatures typically exceeding 1000°C in order to form the final product. However, in recent years, new processes have been developed that can form sintered structures around room temperatures. In this study, we have developed our own unique low-temperature manufacturing technology called the 'ABCD Method' (Acid-Base Chemical Densification). This method utilizes the low-temperature synthesis reaction of composite oxides to solidify ceramics. Recently, more efficient manufacturing has become possible by optimising experimental conditions using machine learning and process informatics. Using this process, some prototype electrochemical devices were fabricated. For example, we have successfully solidified several perovskite-type composite oxides at temperatures below 150°C. When producing BaZrO₃ with amorphous hydrated ZrO₂ as the raw material, the powder was formed into pellets using a uniaxial press. After treatment for 100 hours at 150 °C in a high-concentration solution of barium hydroxide, electrolyte material of BaZrO₃ with a relative density exceeding 90% was obtained by developed ABCD method.

CA-5:L43  Design of Porous Silica Compacts via Cold Sintering Process
SHIORI NAWA¹, YEONGJUN SEO¹, YOSHIFUMI KONDO¹, TOMOYO GOTO^1,2, TOHRU SEKINO¹, ¹SANKEN, The University of Osaka, Ibaraki, Osaka, Japan; ²Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan

The cold sintering process (CSP) has attracted much attention as an innovative method that enables the densification of inorganic materials at temperatures below 300 °C. In CSP, a mixture of inorganic powders and a small amount of solvent is subjected to heating and pressing. This promotes particle rearrangement and dissolution–precipitation reactions at the particle interfaces, resulting in the densification of materials. However, most studies on CSP have focused on dense structures, and few studies have reported porous structures prepared using CSP. Therefore, methods for controlling the pore structure, including the pore shape and distribution, have not yet been established. In this study, we aimed to fabricate porous sintered bodies below 200 °C using CSP with pore-forming agents. Amorphous spherical silica, selected as the starting material, was mixed with an NaOH solution and combined with foaming or leaching agents, followed by CSP at temperatures below 150 °C and pressures of 200–300 MPa. After washing to remove the pore-forming agents, porous silica compacts with porosities ranging from 7% to 60% were obtained successfully. The pore formation behavior, microstructure, and mechanical properties of the resulting sintered bodies will be discussed in detail.

CA-5:L44  Spontaneous Crystallization of Amorphous SiC
T. AYVAZYAN¹, M. ZAKARYAN¹,K. NAZARETYAN¹, K. MANUKYAN², S. KHARATYAN¹, ¹Laboratory of Macrokinetics of Solid State Reactions, Institute of Chemical Physics NAS of Armenia, Yerevan, Armenia; ²Nuclear Science Laboratory, Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN, USA

As refractory materials, preceramic-polymer-derived SiC-based ceramics hold great promise, however, precise control of their properties requires a detailed understanding of the amorphous-to-crystalline phase transformations. To facilitate the development of processing protocols for SiC ceramics the crystallization behavior of a commercial polymer derived amorphous SiC (a-SiC) was extensively studied using high-speed and high-pressure–high-temperature methods. For the first time, amorphous SiC was shown to undergo self-sustaining spontaneous crystallization (SC) under rapid heating conditions. Flash-Joule-based high-speed temperature scanning method enabled investigation of the exothermic SC over heating rates of 1.7–90 ⁰C/s, significantly enhancing extending the regimes accessible in conventional crystallization studies. Kinetic analysis combined with high-resolution microstructural characterization provided comprehensive insight into the SC mechanism. In parallel, high-pressure–high-temperature experiments (up to 7Gpa, 2000^oC) coupled with in-situ energy-dispersive X-ray diffraction and electroconductivity measurements enabled direct comparison between slow and spontaneous crystallization pathways and microstructure evolution.

Session CA-6 Inorganic Functionally Graded Materials

CA-6:IL45  Synthesis of Functional Electrochemical Materials from Inorganic–organic Hybrid Precursors
YOSHIYUKI SUGAHARA, School of Advanced Science and Engineering and Kagami Memorial Institute for Materials Science and Technology, Waseda University, Tokyo, Japan

Inorganic-organic hybrids have been extensively developed. In addition to their uses as functional materials, they can also be employed as precursors, which are typically converted into inorganic functional materials via thermal decomposition. We have developed the preparation methods of various hybrid precursors for preparing inorganic functional materials. One example is porous metal-containing nitrogen-doped carbon materials, which were prepared from precursors primarily composed of organic polymers and soft templates via pyrolysis under ammonia and nitrogen atmospheres. Transition metals such as cobalt and iron were doped as cations and were converted into metals and metal nitrides during pyrolysis. The resulting carbon materials were mainly obtained as powders, although thin films could also be prepared. The other example is high-entropy spinel sulfide with a hollow sphere structure, which was prepared via thermal decomposition of the precursor obtained by the reaction of ethanol containing divalent Co, Cu, Mn, Ni, and Zn cations with carbon disulfide and N, N, N', N'', N''-pentamethyl diethylenetriamine. The resulting materials exhibited outstanding electrochemical performance as electrocatalysts or a supercapacitor electrode.

CA-6:IL46  Additive Manufacturing of Zirconia-based Multi-material Components with Improved Mechanical Resistance
FEI ZHANG^1,2, JUNHUI ZHANG^1,2, B. NEIRINCK³, J. VLEUGELS¹, ¹KU Leuven, Department of Materials Engineering, Leuven, Belgium; ²KU Leuven, Department of Oral Health Sciences, BIOMAT -Biomaterials Research group & UZ Leuven, Dentistry, Leuven, Belgium; ³Schaeffler Aerosint SA, Herstal, Belgium

Zirconia ceramics exhibit enhanced mechanical properties due to transformation toughening but remain brittle with a linear fracture mode. Combining ceramics with metals enables multi-material systems with superior structural and functional properties. In this work, a binder-free Selective Powder Deposition (SPD) additive manufacturing technology was combined with spark plasma sintering (SPS) to fabricate layered zirconia–nickel multi-material components with 30, 50 and 70 vol% Ni in flat and wavy architectures. Optimized sintering at 1200–1300°C and ~30 MPa allowed to produce fully dense components without delamination or cracks. Due to thermal expansion mismatch, the zirconia layers were under compressive stress, and Ni incorporation transformed the fracture behavior of the laminate from brittle to plastically deformable and damage-tolerant. Cracks in the ceramic phase were arrested at the Ni layers where plastic deformation occurred. Importantly, the additively manufactured architecture and Ni content significantly influenced the mechanical response, with wavy patterns in case of Ni contents below 50 vol% giving rise to better plasticity under static and cyclic bending, as confirmed by digital image correlation.

CA-6:L47  Room-Temperature Crack Healing of TiC Ceramics via Electrochemical Process and its Mechanism
JINYU LIU¹, YEONGJUN SEO¹, YOSHIFUMI KONDO¹, TOMOYO GOTO^1,2, TOHRU SEKINO¹, ¹SANKEN, The University of Osaka, Ibaraki, Osaka, Japan; ²Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan

Titanium carbide (TiC) exhibits a combination of covalent, ionic, and metallic bonds simultaneously, imparting both ceramic and metallic features. However, owing to the inherent brittleness of ceramics, cracks can easily occur on their surface and/or inside. Although heat treatment–induced crack healing has been widely investigated, it can only be induced at high temperatures and under prolonged conditions. In this study, we demonstrate the room-temperature crack healing of TiC ceramics through an anodic oxidation method, where the oxides fill the cracks on the surfaces of TiC ceramics. For this purpose, TiC ceramics were prepared using hot-press sintering at 1800 °C, and then the cracks were introduced. To observe the crack healing behavior, the types of electrolyte solution, voltages, and processing times were controlled during anodic oxidation. After the anodic oxidation in 2 mol/L NaOH solution with a voltage of 0.25 V and a reaction time of 3 h, visible titanium oxides were observed near the cracks, and the flexural strength of the cracked TiC specimen was recovered to approximately 80% (from 52% before) of that of the TiC specimen with no cracks. These results validate the possibility of room-temperature crack healing in TiC ceramics using an electrochemical method.

Session CA-7 SHS ceramics

CA-7:L48  Synthesis of Non-stoichiometric High-entropy Carbides and Carbohydrides based on Transition Metals of Groups 4 and 5 (Ti-Zr-Hf-V-Nb)
A. HOVHANNISYAN¹, S. DOLUKHANYAN¹, O. TER-GALSTYAN¹, N. MNATSAKANYAN¹, G. MURADYAN¹, E. VARDANYAN¹, S. KHASANOV², S. MARDANYAN³, ¹A.B. Nalbandyan Institute of Chemical Physics of Armenian NAS, Yerevan, Armenia; ²Y.A. Osipyan Institute of Solid-State Physics, Russian Academy of Sciences, Chernogolovka, Moscow district, Russia; ³H. Buniatian Institute of Biochemistry of Armenian NAS, Yerevan, Armenia

The aim of the present work is to study the SHS formation of non-stoichiometric High-entropy carbides and carbohydrides of 4 and 5 group metals (Ti-Zr-Hf-V-Nb) with carbon content of 0.4-0.8 wt%. During SHS-combustion of carbon mixture with three, four and five metals in argon, the reaction is driven by carbon (Т_comb= 1600-1800^оС), and single-phase high entropy ternary, quaternary and penta- non-stoichiometric carbides with FCC structure are formed, for example: Ti_0.4V_0.3Nb_0.3C_0.5, Ti_0.3Zr_0.3V_0.2Nb_0.2C_0.5, Ti_0.25Zr_0.25Hf_0.1V_0.2Nb_0.2C_0.5, Ti_0.2Zr_0.2Hf_0.2V_0.2Nb_0.2C_0.5,etc. During SHS-combustion of similar mixture in hydrogen, nearly single-phase high entropy ternary, quaternary and penta- non-stoichiometric carbohydrides with FCC structure are formed, for example: Ti_0.4V_0.3Nb_0.3C_0.5H_0.46, Ti_0.3Zr_0.3V_0.2Nb_0.2C_0.5H_0.5, Ti_0.2Zr_0.2Hf_0.2V_0.2Nb_0.2C_0.5H_0.65, Ti_0.25Zr_0.25Hf_0.1V_0.2Nb_0.2C_0.5H_0.66,etc. Combustion reactions in hydrogen can be considered as conjugate reactions: initially, the combustion reaction is driven by carbon, and non-stoichiometric carbides are formed. Then during cooling, at ⁓ 800°C, into the unfilled interstices of non-stoichiometric carbides, i.e., into structural vacancies of the crystal lattice, hydrogen is introduced, forming carbohydrides. Hydrogen conditions two features of synthesized compounds: 1 - the samples are fragile and easily crushed into agglomerates with size less than 50 µm (even down to submicron sizes of nano-sized crystallites 120÷250 nm); 2 - after hydrogen removal by Hydride Cycle dehydrogenation, the structure of non-stoichiometric high-entropy carbides is completely restored in ~ 60 minutes at temperature ⁓1000°C. Moreover, partial homogenization of the resulting products occurs bringing to the formation of single-phase high-entropy carbides. The enormous advantages of the developed highly efficient, energy-saving, waste-free and safe SHS method of high-entropy non-stoichiometric carbides and carbohydrides synthesis can be very attractive for industry with a commercial interest.

CA-7:L49  The Influence of Nb, Cr, Mn Alloying on the Process of γ -TiAl Formation by High-temperature Synthesis (SHS) and Hydride Cycle (HC) Methods
G. MURADYAN¹, S. DOLUKHANYAN¹, O. TER-GALSTYAN¹, N. MNATSAKANYAN¹, S. KHASANOV², S. MARDANYAN³, E. VARDANYAN¹, ¹A.B. Nalbandyan Institute of Chemical Physics of NAS RA, Yerevan, Republic of Armenia; ²Y.A. Osipyan Institute of Solid-State Physics of RAS, Chernogolovka, Moscow District, Russia; ³H.Kh. Buniatian Institute of Biochemistry of NAS RA, Yerevan, Republic of Armenia

In this work, a new method for synthesis of Ti-47.5Al-2Cr/Mn-2Nb alloy is elaborated, based on using of two techniques: Self-propagating High-temperature Synthesis (SHS) of metal hydrides, and Hydride Cycle (HC) formation of metal alloys. Four compositions are studied: Ti-47.5Al-2Cr-2Nb, Ti-47.5Al-2Mn-2Nb, Ti-47.5Al-2Cr-2Mn-2Nb and Ti-47.5Al-1Cr-1Mn-2Nb. First, titanium and niobium hydrides were synthesized using the SHS method; then, from these hydrides the alloys of the indicated compositions were synthesized in HC. Tetragonal γ-TiAl phase was synthesized, containing 11-22%of hexagonal α2-Ti3Al phase. The thermograms of HC processes, the DTA curves, and the absence of melting traces on the surfaces of the samples indicate a solid-phase diffusion reaction mechanism of γ-TiAl and all the studied compositions formation in HC. The main advantages of the used method over the traditional ones are: diminution of working temperatures from 1800-2600 to 600-1000оC, and duration from tens to 1.0-2 hours; one-stage and waste-less processing of formation of the multicomponent and doped alloys of given chemical and phase composition, without necessity of repeated re-melting. These advantages ensure lower energy consumption and low manufacturing cost.

CA-7:L50  Ti₂AlB MAX Phase and MXene Derivative Prepared by Self-Propagating High-Temperature Synthesis
N. AMIRKHANYAN¹, M.A. RODRIGUEZ², J. ROSEN³, S. AYDINYAN¹˒⁴, S. KHARATYAN¹, ¹A.B. Nalbandyan Institute of Chemical Physics, NAS RA, Yerevan, Armenia; ²Instituto de Cerámica y Vidrio, CSIC, Madrid, Spain; ³Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, Sweden; ⁴Tallinn University of Technology, Tallinn, Estonia

Ternary layered MAX phases (Mₙ₊₁AXₙ, n = 1–3) exhibit a unique combination of metallic and ceramic properties owing to their nanolaminated structure. Among them, boron-containing MAX phases have recently gained attention for their exceptional hardness, conductivity, thermal stability, and chemical resistance. Theoretical studies have predicted Ti₂AlB to be a stable phase analogous to Ti₂AlC and Ti₂AlN, though its experimental synthesis remains challenging due to the high reactivity of boron and competing phase formation. In this work, Ti₂AlB MAX phase and its MXene derivative were synthesized via the self-propagating high-temperature synthesis (SHS), providing a rapid and energy-efficient route for producing phase-pure materials. The obtained powders were characterized by XRD, SEM, TEM, and FTIR analyses, confirming Ti₂AlB formation, layered morphology, and partial etching into its boron-based MXene. The combination of high-temperature reaction kinetics and in-situ reduction during SHS ensured effective diffusion between elements. The results contribute to expanding SHS approaches for fabricating boride MAX and MXene materials with enhanced structural integrity, chemical tunability, and potential use in energy storage, protective coatings, and electronic applications.

Session CA-8 The glass ceramics route

CA-8:IL52  Solid-state Field-assisted Ion Exchange of Ag in Lithium Aluminum Silicate Glass-ceramics
M. BIESUZ, V.M. SGLAVO, G.D. SORARÙ, Department of Industrial Engineering, University of Trento, Trento, Italy

Lithium-aluminum-silicate glass-ceramics (LAS) are pivotal in various applications as they combine excellent mechanical and functional properties. Herein, we report the solid-state field-assisted (Ag→Li,Na) ion exchange in LAS glass-ceramics containing β-quartz and β-spodumene solid solutions. The ion-exchange is extremely rapid. Deep silver penetration (>100 μm) can be achieved within a few minutes (<5 min), this being proportional to the treating time and applied current. The elemental profiles are characterized by a relatively complex shape, which reflects the different alkali mobility in the different phases. Strong evolution of the structure and microstructure of the glass-ceramics occurs during the process. The ion-exchanged materials possess improved resistance to surface flaw formation and antimicrobial activity.

Session CA-9 Other special processing routes

CA-9:IL53  Light-assisted Solidification Templating of Preceramic Polymers towards Porous Ceramic CO2 Utilization Frameworks
T. KONEGGER, K. RAUCHENWALD, TU Wien, Institute of Chemical Technologies and Analytics, Vienna, Austria

Carbon utilization is one of the key strategies to reduce the impact of anthropogenic carbon dioxide emissions. Porous ceramics represent an important pillar in utilization scenarios ranging from catalyzed chemical reactions to biosynthetic approaches, the ceramic materials being frameworks for the active constituents. In this contribution, we present the combination of photopolymerization with solidification templating (i.e., freeze-casting) of preceramic polymers as an innovative tool to obtain polymer-derived silicon oxycarbide materials with pore structures difficult or impossible to achieve via conventional means, with a focus on developing new material concepts for prospective CO2 utilization applications. After a discussion of the underlying processing principles and control of pore features, the focus is set on the presentation of fields of potential applications such as CO2 methanation. In addition to the use of monolithic structures with a wide range of pore morphologies, new processing approaches towards porous ceramic microspheres based on photopolymerization-assisted solidification templating will be presented, which are expected to contribute to the implementation of more sustainable chemical conversion processes.

CA-9:IL54  High-Pressure Synthesis and Crystal Chemistry of Novel Functional Transition-Metal Silicides
T. SASAKI, T. KITAHARA, K. NIWA, M. HASEGAWA, Department of Materials Physics, Nagoya University, Nagoya, Aichi, Japan

High-pressure synthesis is a powerful method for synthesizing a variety of novel compounds. Metal silicides have attracted attention due to their intriguing structural diversity and potential applications in various fields, and many silicon-rich alkali and alkaline-earth silicides have been newly discovered under high-pressure conditions. These high-pressure phases of Si-rich silicides often have characteristic crystal structures with covalent bonds, such as Zintl phases and clathrate compounds. In contrast, there have been no reports on the silicon-rich transition-metal silicides. We focused on the binary system of 3d transition metals and silicon as targets for synthesizing high-pressure phases because several Ge-rich transition-metal germanides have been reported, such as CrGe2, MnGe4, and CoGe4 [1,2]. In this presentation, We will discuss the synthesis and crystal chemistry of several silicon-rich transition metal silicides that we have successfully synthesized [3].
[1] H. Takizawa, T. Sato, T. Endo, and M. Shimada, J. Solid State Chem., 88, 384 (1990); [2] T. Sasaki, K. Kanie, T. Yokoi, K. Niwa, N.A. Gaida, K. Matsunaga, and M. Hasegawa, Inorg. Chem., 60, 1767 (2021); [3] T. Sasaki, K. Takano, T. Kitahara, N.A. Gaida, K. Niwa, and M. Hasegawa, Inorg. Chem., 64, 19989 (2025).

CA-9:IL55  In-situ Exploration of New Materials under Extreme Conditions using the Large Volume Press at beamline P61B DESY
S. BHAT, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany

The Large Volume Press (LVP) 'Aster-15' is installed at the DESY PETRA III P61B beamline. It is ideal for high-pressure, high-temperature (HPHT) experiments, making use of the high-energy white beam delivered by the ten damping wigglers [1]. This powerful beam enables fast in situ energy-dispersive X-ray diffraction (EDXRD) using two high-purity Ge detectors at HP-HT conditions (up to 25 GPa and 2000 °C routinely). Users can also access offline LVP time (without X-rays) via rapid access to perform HP-HT experiments, e.g. in preparation for or following beam time, to carry out bulk synthesis of the newly discovered quenchable phase. Thus, P61B is unique in its online and offline experimental capabilities. It enables the in-situ tracking and ex-situ synthesis of novel materials using the Aster-15. This talk will shed light on the synthesis of different novel materials at the beamline. These will include HP-HT synthesis and characterisation of the structural and mechanical properties of a γ-Si₃N₄/Hf₃N₄ ceramic nanocomposite derived from a single-phase amorphous Si-Hf-N precursor [2], a doubly ordered perovskite NaYbZnWO₆, 'Nolanite-type' tin germanium oxy-nitride SnGe₄N₄O₄ [3], 'Rh₂S₃-type' tin oxy-nitride Sn₂N₂O [4], 'spinel-type' ternary Si-Ti-N [5], and others.
[1] R. Farla, et al., Journal of Synchrotron Radiation (2022); [2] W. Li, et al., Journal of Advanced Ceramics (2023); [3] P. Goll´e-Leidreiter; et al. Acta Crystallographica Section B (2024); [4] S. Bhat, et al., Chemistry – A European Journal (2020); [5] S. Bhat, et al., Scientific Reports (2020)

CA-9:IL56  Using Cellulose Nanofibers as Polymeric Support and Biotemplate of Photocatalytic Nanophases to Shape 3D Advanced Structures
Z. GONZÁLEZ^1,2, J.M. LUQUE¹, G. ESTRELLA-GUISADO¹, R. MONTENEGRO^1,2, P. ORTEGA-COLUMBRANS^3,4, A. RODRÍGUEZ^1,2, B. FERRARI^2,3, ¹BioPrEn Group (RNM-940), Chemical Engineering Department, Instituto Químico para la Energía y el Medioambiente (IQUEMA), Faculty of Science, Universidad de Córdoba, Córdoba, Spain; ²Unidad Asociada CSIC-UCO. Fabricación aditiva de materiales compuestos basados en celulosa funcionalizada, obtenida de residuos de biomasa, Spain; ³Instituto de Cerámica y Vidrio, CSIC, Campus de Cantoblanco, Madrid, Spain; ⁴COLFEED4Print S.L., Tres Cantos, Madrid, Spain

The development of sustainable photocatalysts is crucial for advancing efficient Advanced Oxidation Processes (AOP). Since TiO₂ emerged as the benchmark photocatalyst in 1972, its limitations have encouraged new strategies to improve activity and expand applications. One promising route involves using cellulose nanofibers (CNFs) as polymeric supports and biotemplates for photocatalytic nanophases. Owing to their high surface area, tunable porosity, mechanical strength, and abundant functional groups, CNFs enable strong interfacial interactions and uniform dispersion of photoactive nanoparticles. This work explores colloidal approaches promoting electrostatic interactions to obtain CNF:TiO₂ and CNF:TiO₂/CuO heterostructures, which are subsequently shaped into 3D architectures via freeze-drying and fused filament fabrication (FFF) using PLA blends. The resulting bio-based composites exhibit enhanced optical, physicochemical, and photocatalytic performance, highlighting the potential of CNFs to design lightweight, sustainable, and hierarchically structured photocatalysts for environmental and energy applications.
The authors acknowledge the financial support regarding to the PID2023-152932OB-I00 and CPP2023-010820 projects, funded by MCIN/AEI /10.13039/501100011033

Symposium CA

Cimtec 2026