Symposium CD

ABSTRACTS

Session CD-1 Thin film deposition techniques and film growth

CD-1:IL01  Conformal and Super-conformal CVD of Binary Compounds in Deep Features : Predictive Model and Results for TiN
L. SOUQUI, Uppsala University, Uppsala, Sweden; J.L. LASTOWSKI, T.K. HUYNH, G.S. GIROLAMI, J.R. ABELSON, University of Illinois at Urbana-Champaign, Urbana, IL, USA

To fabricate advanced nanoscale devices, film deposition processes are needed to afford conformal (step coverage = 1) and super-conformal (step coverage >1) thickness in deep features such as via and trenches. Chemical vapor deposition can in principle meet this challenge because the reaction probability of the chemical precursors with the growth surface can be moderated by the presence of adsorbates and reaction intermediates. However, the reaction probability is also strong function of the precursor chemistry, temperature, and fluxes. With careful assumptions, we demonstrate that the kinetics of the deposition process can be accurately described by an analytical model based on competitive site-blocking and reaction. The strengths of this model are its generality and small number of physical parameters. As a test system, we establish the model parameters for the growth of TiN films on planar substrates from the reaction of tetrakis(dimethylamido)titanium (Ti(N(CH3)2)4) and ammonia (NH3). We then extend the model to account for precursor transport in high-aspect ratio features, and map the model predictions against results for the (super)conformal growth of TiN in trenches with aspect ratio ≤ 13. We conclude by showing what ranges of parameters are needed in a general case.

CD-1:IL02  High-Performance Ferroelectric GaScN Thin Films by Sputtering for Next-Generation Devices
M. UEHARA, K. HIRATA, S.A. ANGGRAINI, H. YAMADA, M. AKIYAMA, National Institute of Advanced Industrial Science and Technology (AIST), Tosu, Saga, Japan; K. OKAMOTO, H. FUNAKUBO, Institute of Science Tokyo, Japan

(Al,Sc)N and (Ga,Sc)N are solid solution materials formed by alloying ScN with AlN or GaN. These compounds exhibit excellent piezoelectric and ferroelectric properties, particularly when ScN is incorporated into the wurtzite lattice, despite its thermodynamic incompatibility. According to equilibrium phase diagrams, ScN does not form solid solutions with AlN or GaN, making these alloys supersaturated solid solutions. Sputtering, a non-equilibrium synthesis method, is especially suitable for stabilizing such metastable phases. In this study, we optimized sputtering conditions for (Ga,Sc)N thin films and successfully synthesized wurtzite-phase (Ga₁₋ₓ, Scₓ)N with Sc concentrations up to x = 0.53. Despite the tendency toward rock salt phases at high Sc content, the optimized process stabilized the wurtzite structure. The resulting films exhibited a maximum piezoelectric coefficient of d₃₃ = 33 pC/N, exceeding that of ScAlN used in RF filters. Ferroelectric measurements revealed a minimum coercive field (Ec) of 1.49 MV/cm, comparable to HfO₂-based materials. Structural analysis showed a strong correlation between lattice constant ratio (c/a) and functional performance, with reduced c/a enhancing both d₃₃ and lowering Ec.

CD-1:IL03  Investigating the Growth of Plasmonic Nanostructures and Thin Films in Real Time During Physical Vapor Deposition
D. BABONNEAU, K. SOLANKI, M. COSTES, M. CHALOPIN, G. ABADIAS, S. CAMELIO, A. MICHEL, F. PAILLOUX, J. RAMADE, S. ROUSSELET, Institut Pprime, Université de Poitiers, CNRS – Poitiers, France; A. COATI, A. RESTA, A. VLAD, SOLEIL synchrotron – Saint-Aubin, France; Y. GARREAU, SOLEIL synchrotron – Saint-Aubin, France and Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Cité, CNRS – Paris, France; M. KAMINSKI, B. KRAUSE, Institute of Photon Science and Synchrotron Radiation, Karlsruhe Institute of Technology – Karlsruhe, Germany

Metallic nanoparticles and thin films attract a great deal of scientific and technological interest, notably because of their potential to serve as active components in plasmonic sensors or transparent conductive electrodes. The development of effective growth strategies using physical vapor deposition is thus essential to further enhance the device’s performance. In this context, the implementation of real-time techniques during growth is of prime importance for improving our mechanistic understanding of nanoparticle and thin film formation at the nanoscale. In this presentation, we will focus on the combination of real-time techniques during metal deposition (magnetron sputtering or e-beam evaporation), including grazing incidence small-angle x-ray scattering, grazing incidence diffraction, substrate curvature measurements, and surface differential reflectance spectroscopy. Using this approach, we will discuss the impact of nitrogen additive on the growth dynamics of ultrathin Ag layers from the very first stages (island nucleation, coalescence) up to formation of percolated and continuous films. We will also examine the influence of oblique angle deposition on the structure and optical response of bimetallic Au-Pd nanoparticles (alloy, core-shell or Janus).

CD-1:L04  Novel Chemical Vapor Deposition Process of ZnO and Ga2O3 Films by Nonequilibrium Atmospheric Pressure N2/O2 Plasma
NORIFUMI FUJIMURA, Department of Physics and Electronics, Osaka Metropolitan Univ. (Osaka Prefecture Univ.), Japan

We have successfully generated a nitrogen plasma near atmospheric pressure with a high electron temperature (>4000 K) and a low gas temperature (<400 K) using dielectric barrier discharge. By employing this non-equilibrium nitrogen plasma, in which the emission corresponding to the N₂ second positive system was predominantly observed, self-limited nitridation of Si at a thickness of approximately 1.8 nm was achieved at room temperature. By introducing only 1ppb O2 gas, oxidation is recognized. We have studied the effect of active species on the growth of oxide films such as ZnO and Ga2O3 in nitrogen nonequilibrium plasma generated near atmospheric pressure using home-made chemical vapor deposition systems. The XRD profiles of ZnO films deposited at various O₂/(O₂ + N₂) gas ratios, ranging from O₂-rich to N₂-rich gas compositions. With decreasing O₂/(O₂ + N₂) ratio, the degree of (0001) preferred orientation in ZnO films was markedly enhanced. These results indicate that N₂ plasma with a small amount of O₂ (<1%) provides superior crystallographic quality compared to O₂-rich plasma. Highly resistive ZnO epitaxial films were successfully fabricated even at a substrate temperature as low as 200 °C. The residual donor concentration was measured to be below 1 × 10¹³ cm⁻³.

CD-1:IL05  Surface-controlled CVD of SiC Coatings on Graphite
JING-JIA HUANG, H. PEDERSEN, U. FORSBERG, Department of Physics, Chemistry, and Biology, Linköping University, Linköping, Sweden; C. MILITZER, C. WIJAYAWARDHANA, SGL Carbon GmbH, Bonn, Germany

Graphite has high thermal stability and is therefore ideal for many high-temperature applications; however, its poor corrosion resistance limits its use in the semiconductor industry. To overcome this, graphite parts are typically coated with a protective layer such as silicon carbide (SiC). However, SiC grown by conventional chemical vapor deposition (CVD) often suffers from non-uniform coating thickness in trenches due to gradual depletion of precursors along the depth of these features. This study presents several CVD approaches to achieve uniform, or conformal, SiC coatings throughout trenches. The key concept of a conformal CVD process is to reduce the surface reaction probability of precursors, either by lowering the deposition temperature or by adding a growth inhibitor, such as HCl. In our pulsed CVD studies, we even achieved superconformal deposition—that is, faster growth at the bottom of the trench than at the opening. This effect is likely due to stronger inhibition at the trench opening. Our findings in improving the coating conformality of SiC at elevated temperatures and moderate pressures could potentially benefit numerous CVD processes for protective coatings using chlorinated precursors, as these coatings are often deposited under such conditions.

CD-1:IL06  Refractory Plasmonic Interfaces for Desalination and Passive Mining
M. MARGESON, NAIZHEN YU, M. DASOG, Dalhousie University, Halifax, Nova Scotia, Canada

Refractory plasmonic materials have emerged as promising alternatives to traditional noble metals for high-temperature and harsh-environment applications, due to their exceptional thermal stability and tunable optical properties. They offer robust plasmonic performance across a broad spectral range, unlocking new possibilities in photonic and energy-related technologies. This presentation will highlight recent advances in the synthesis of plasmonic transition metal nitride and carbide nanoparticles via solid-state methods. The nanoparticles can then be cast into simple films to create photothermal interfaces for solar driven desalination and mining. These results underscore the potential of refractory plasmonic materials for practical deployment in next-generation energy and environmental systems.

CD-1:IL07  Strategic Lattice Manipulation in Ti–B–N Thin Films for Advanced Material Design
R. JANKNECHT, Institute of Materials Science and Technology, TU Wien, Vienna, Austria, and Empa, Swiss Federal Laboratories for Materials Science and Technology, Thun, Switzerland

Over the past half-century, transition metal nitride coatings, such as TiN, have become essential for enhancing the durability and performance of industrial tools and components. Controlled alloying using physical vapor deposition (PVD) techniques allows for the formation of metastable ternary nitrides and precise tuning of coating properties, unlocking new functionalities―an attractive approach for both industry and science. Manipulating either the nonmetal face-centered cubic TiN sublattice with nitrogen vacancies or the metallic sublattice through strategic metal alloying can achieve a solubility of 10 at.% boron (B) in TiN (i.e., 20 at.% in the nonmetal sublattice). This results in a hardness of 37.1 ± 1.9 GPa and the highest fracture toughness (KIC) of 3.0 ± 0.2 MPa·m¹/² among the studied samples.Supported by ab initio density functional theory (DFT) calculations this microalloying concept opens a new avenue for the design of novel materials with tailored properties, extending beyond the Ti–B–N system to the synthesis of other metastable material systems.

Session CD-2 Multifunctional thin films and coatings

CD-2:IL08  Thin-film Ceramics for Energy Applications
P. EKLUND, Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden

Thermoelectric devices have the potential to contribute to energy harvesting in society by directly converting heat into electricity or vice versa. However, the conversion efficiency of thermoelectric devices of today is limited. In this lecture, I present an overview of our work on multicomponent CrN-, ScN-, and Ca3Co4O9-based thin films. We have developed methodology for highly textured as well as nanoporous virtually phase-pure Ca3Co4O9 thin films. These can further be deposited on flexible mica substrates, enabling flexible inorganic thermoelectric thin films that withstand repeated bending. They can also be made as free-standing films and as nanoporous materials for reduced thermal conductivity. ScN thin films exhibit an anomalously high power factor (S2/ρ) for transition metal nitrides, but has high thermal conductivity, thus its ZT is low (~0.2). To reduce lattice thermal conductivity, potential strategies are nanostructuring, alloying or nanoinclusion formation. Pure CrN exhibits n-type conduction with a high power-factor enabled by a high electron concentration thermally activated from N vacancies, and alloys can be made of rocksalt-Cr1-xScxN. Multicomponent alloying of ScN and CrN in alloys such as CrMoVWN are further investigated.

CD-2:IL09  Engineering with Gases: Using Vapors to Create Multifunctional Hybrid Materials
M. KNEZ, CIC nanoGUNE, San Sebastian, Spain, and Ikerbasque, Bilbao, Spain

The secret of nature's success lies in its masterful integration of organic and inorganic components across multiple length scales. This talk will present a transformative vision for replicating this synergy, not through top-down manufacturing, but via bottom-up synthesis using the precise chemistry of vapor phases. We will introduce a powerful suite of techniques under the umbrella of Atomic Layer Processing (ALP) - including Atomic Layer Deposition (ALD), Molecular Layer Deposition (MLD), and Vapor Phase Infiltration (VPI). This toolbox allows us to engineer materials with unparalleled atomic-level control, directly infusing bulk substances and surfaces with plentiful properties. We will take a journey through this modern "material alchemy," demonstrating its power to tackle grand engineering challenges. The talk will illustrate how we can radically enhance the mechanical strength and toughness of (bio)polymers; provide textiles and surfaces with antimicrobial properties inspired by insect cuticles; and fabricate flexible, self-repairing electronic components that mimic the resilience of biological systems. By moving from imitation to integration, we are programming multifunctionality directly into the fabric of materials themselves.

CD-2:IL10  Engineered Thin-Film Oxygen Electrodes for Next-Generation Reversible Solid Oxide Cells
M. BURRIEL, LMGP laboratory, CNRS, Grenoble, France

This study explores La2NiO4+δ (L2NO4) and Pr-substituted La1-xPrxNiO4+δ (LPNO) thin films as oxygen electrodes for low-temperature solid oxide cells (LT-SOCs). LPNO compounds combine strong mixed ionic–electronic conductivity with fast oxygen reduction reaction (ORR) kinetics. Films were synthesized by Pulsed Injection Metal-Organic Chemical Vapor Deposition (PI-MOCVD), tuning microstructure and electrochemical behavior through deposition temperature and thickness. ORR rate-limiting steps were analyzed using electrochemical impedance spectroscopy and electrical conductivity relaxation. Optimized electrodes deposited on YSZ single-crystal electrolytes with Ni-Ce0.9Gd0.1O2-δ fuel layers delivered 70 mW·cm⁻² at 0.7 V (SOFC) and –44 mA·cm⁻² at 1.3 V (SOEC) at 600 °C. Nano-columnar L2NO4 and LPNO electrodes grown on commercial half-cells also enabled reversible operation. These results highlight the potential of L2NO4- and LPNO-based electrodes for efficient, durable LT-SOCs.

CD-2:L11  The Effects of Grain Boundary Structure on the Mechanical Properties of Molybdenum Disulfide
M. CHANDROSS¹, R.D. MOORE², S. BOBBITT¹, I. WINTER¹, J. CURRY¹, L. LEVANDOSKY², S. RENAUD², F. ABDELJAWAD², ¹Sandia National Laboratories, Albuquerque, NM, USA; ²Lehigh University, Bethlehem, PA, USA

Molybdenum disulfide (MoS2) is widely used as a lubricant in vacuum applications over range of operating temperatures. As many processing techniques yield polycrystalline MoS2, establishing grain boundary (GB) structure-property relations is key to designing MoS2 with tailored mechanical properties. We present the results of atomistic simulations that study the structure and mechanical properties of GBs in MoS2 under tensile deformation. Our results reveal that above 100 K deformation is characterized by the nucleation of shear bands from GBs while at lower temperatures, the tensile deformation is dominated by the nucleation and propagation of deformation fronts. Quantitative analysis reveals a decrease in the ultimate stress and strain of MoS2 bicrystals with increasing temperature. Simulations of metastable GBs reveal that the strength and ductility decrease with the increase in energy of these boundary structures.
SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 (SAND2022-1056 A).

CD-2:IL12  Electronic Structure and Phase Formation in Nanolaminated Ceramics
D. MUSIC, Department of Materials Science and Applied Mathematics, Malmö University, Malmö, Sweden

Nanolaminates are typically understood as materials composed of nm-thick layers, a structure that often leads to unusual combinations of properties or the emergence of new phenomena. Ductile ceramics have been realized in systems like MAX phases, perovskite borides, Mo2BC, and NaCl-structured ceramics. We demonstrate that the key feature in these materials is a layered electronic structure, which is proposed as a critical prerequisite for unexpected properties. As such, our findings broaden the definition of nanolaminates beyond their conventional structural criteria. The tunability of transport properties in nanolaminated ceramics is further explored through 2D oxides. Specifically, NbO2 and SnO are investigated as case studies. NbO2 forms 2D nanostructures that compete with a 1D growth mode. To understand the formation mechanism of these 2D nanostructures relative to the competitive nanorod growth, density functional theory (DFT)-based molecular dynamics was employed. In contrast, SnO exhibits an unusual dendritic microstructure, unexpected for sputtered thin films. Modeling the evolution of 2D SnO nanostructures at the DFT level is computationally intensive. To overcome this challenge, we developed artificial neural networks trained on small-cluster Sn-O surface interactions.

CD-2:IL13  Chemical Vapour Deposition Growth of CrN Thin Films for Thermoelectric Energy Conversion.
L.J. ADAMS, S. BASERGA, L. SOUQUI, E. SADEK, Uppsala University, Uppsala, Sweden; L. VON FIEANDT, AB Sandvik Coromant, Hägersten, Sweden and Uppsala University, Uppsala, Sweden; P. EKLUND, Uppsala University, Uppsala, Sweden

Chromium nitride (CrN) is a promising high temperature thermoelectric material with low electrical resistivity, high Seebeck coefficient and power factor. To date, high-quality CrN films have only been synthesised using physical vapour deposition (PVD) methods. These approaches, are inherently limited by their line-of-sight nature, which can contribute to columnar growth morphologies and poor step coverage, factors that can adversely affect the electrical properties of the material. In contrast, chemical vapour deposition (CVD) offers an attractive route for producing dense and uniform thin films. However, to the best of our knowledge, and in spite of extensive endeavours to deposit CrN using a wide range of precursors, the resulting films reported to date have suffered from high levels of contamination (C, O, Cl). Consequently, no high-quality CrN films have yet been reported using thermal CVD, making this study the first to demonstrate pure, stoichiometric n-type CrN on both single-crystal sapphire and tungsten carbide substrates. CVD can provide new insights into the growth mechanisms, as well as alternative approaches to defect chemistry and morphologies of the CrN thin films; potentially enabling tuneable thermoelectric performance beyond what has been achieved with PVD.

CD-2:IL14  Advanced Electrocatalysts for Green Hydrogen and Ammonia Synthesis
S. MATHUR, Chair, Inorganic and Materials Chemistry, University of Cologne, Cologne, Germany

Thin films of functional oxides offer tunable electronic properties and high surface-area interfaces, making them ideal platforms for efficient small molecule activation in green hydrogen and ammonia production. The growing possibilities of engineering nanostructures in various compositions (pure, doped, composites, heterostructures) and forms has intensified the research on the integration of different functional material units in a single architecture to obtain new photo- and electrocatalytic materials. We report here on the influence of external magnetic fields applied parallel or perpendicular to the substrate during plasma enhanced chemical vapor deposition of transition metal oxides. Films grown from transition metal precursors showed pronounced changes in crystallographic textures depending upon whether CVD was performed with or without external magnetic field. Investigations on the water splitting properties of the hematite films in a photoelectrochemical reactor revealed superior photocurrent values of hematite photoanodes deposited in external magnetic field. This talk will demonstrate that applying magnetic fields during growth of thin films can fundamentally reconfigure lattice characteristics. This is manifested in the alteration of their crystallographic structure and the topology of the surface states. This dual modulation precisely tailors their intrinsic and emergent electrochemical properties. The MF-CVD approach establishes a groundbreaking and versatile strategy to transform functional materials at the atomic level.

CD-2:L15  Design and Synthesis of Zirconia Submicrospheres Metacoating for Radiative Cooling
ZHONGYANG WANG, HAO GONG, XIAO ZHOU, TONGXIANG FAN, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China

Radiative cooling is crucial for reducing undesirable energy consumption induced by thermoregulation technology. However, current conventional passive coolers still suffer from challenges such as vulnerability to harsh service conditions and suboptimal radiative cooling performance without guidance from optical simulation. Metacoating based on photonic structure design and all-inorganic components can overcome these drawbacks and is becoming indispensable in harsh space conditions. In this work, a metacoating for radiative cooling is fabricated by combining zirconia submicrospheres (ZS) and potassium silicate. ZS with optimal diameters are synthesized to efficiently scatter sunlight. The metacoating has a solar absorption of only 4%. The low solar absorption is attributed to the high backscattering efficiency of ZS and their high-volume fraction, as demonstrated by simulations using the Mie scattering theory and Monte Carlo ray-tracing method. This study demonstrates that metacoating formed by ZS with a larger bandgap and a specific particle size scattering structure will provide a perspective for promoting radiative cooling technology.

CD-2:L16  Lead-Free KNN Piezoelectric Coatings on Ti6Al4V via Screen Printing: Systematic Optimization for Next-Generation Bioactive Implants
M. REZAPOURIAN, J. NECIB, A. KARIMINEJAD, M. BCHATNIA, R.E. ROJAS-HERNANDEZ, I. HUSSAINOVA, Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Tallinn, Estonia

Electrically active implants that harvest load-induced piezoelectric signals show promise for enhancing bone healing. Potassium sodium niobate (KNN) is a viable lead-free candidate; however, producing strongly adherent KNN coatings on laser powder bed fusion (LPBF) Ti6Al4V substrates remains challenging. This study employs screen printing technique to deposit KNN coatings onto the surface of LPBF fabricated Ti6Al4V and systematically optimizes processing parameters through a two-stage approach: stage I uses a structured experimental matrix varying sintering temperature and atmosphere (air, argon, nitrogen) to optimize interface quality, phase purity, and coating density (XRD, SEM/EDS); and stage II fixes optimal parameters and varies coating thickness, examining microstructure, adhesion, mechanical properties (hardness, elastic modulus, fracture toughness) and tribology performance. Multi-objective optimization is employed to balance competing outcomes and identify optimal processing windows. This approach demonstrates that screen printing offers a simple, scalable, and cost-effective route for fabricating functional KNN coatings on LPBF-fabricated titanium alloy substrates for piezoelectric bioactive implant applications.

CD-2:L17  Smart Window Photoprotective Nanocomposite Coatings for Energy Savings
C. ROSCINI¹, L. VALLAN¹, D. RUIZ-MOLINA¹, A. CARRASCULL², J. HERNANDO³, J. OTAEGUI², ¹Catalan Institute of Nanoscience and Nanotechnology, Bellaterra, Spain; ²Futurechromes SL, Spain; ³Autonomous University of Barcelona, Spain

Buildings account for approximately 40% of the global energy consumption, 50% of which is used for heating and cooling systems to preserve the thermal comfort of the inhabitants. Such consumption is going to increase in the next years, especially for the use of air conditioning systems. This is due to both the global warming and the modern architecture that designs and create new buildings with increasing surface are of transparent envelopes. Transparent windows are ideal to allow sunlight entering the building and provide natural lightening. However, they are also responsible to favour the solar heat gain inside buildings. While this is appreciated in winter time or in geographical regions with cold average temperature, it is not desired in summer and warm areas, which have to compensate the heat excess with air conditioning systems. Smart windows are proposed as solution to this as they allow to regulate the amount of sunlight can go inside the buildings. Herein we will present a new approach, based on highly performing polymer nanocomposites embedding active oil nanodroplets, which exhibit self-regulation of the transmitted sunlight upon light and/or temperature stimulus. The films and coatings are obtained through low-cost materials, sustainable and low-energy processes.

CD-2:L18  Thin Films for Improved Gas Sensor Performance
SANG SUB KIM, Inha University, Incheon, Republic of Korea; HYOUN WOO KIM, Hanyang University, Republic of Korea

This study focuses on the rational design and surface engineering of SMO thin films to achieve enhanced gas sensing performance. Various modification strategies—including noble metal nanoparticle decoration (e.g., Pt, Au), formation of heterojunctions between dissimilar oxides, and hybrid functionalization with organic molecules—are systematically investigated. These approaches enable precise control over the surface electronic structure, catalytic activity, and charge transfer pathways, resulting in improved gas adsorption kinetics and selectivity. Experimental results confirm that such engineered thin films exhibit significant improvements in sensitivity, selectivity, response and recovery speed, detection limit, and long-term stability, even under varying humidity and temperature. The findings highlight that optimizing surface interfaces and chemical functionalities within SMO thin films is key to achieving high-performance, durable, and reliable gas sensors. This research provides valuable insights into thin-film design strategies for next-generation chemiresistive sensors with enhanced real-world applicability.

Session CD-3 Hard and wear-resistant coatings

CD-3:IL19  Controlling Ceramics’ Toughness through Polymorphic Competition
D.G. SANGIOVANNI, Linköping University, Sweden

From nanoscale devices to macroscale components, a fundamental understanding of plasticity and fracture is key to realizing ceramics that ensure safe and durable performance. However, a mechanistic understanding of these phenomena remains largely elusive due to the length and timescales at which crack initiation starts. The talk presents atomistic methods – based on accurate and efficient machine-learning interatomic potentials (MLIP) – to characterize intergranular and transgranular fracture properties through stress-intensity- (K) -controlled loading. The ceramic’s fracture toughness and strength during mode-I, mode-II or mixed-mode loading can be extrapolated to the macroscale with high reliability and for different crack geometries. Taking Ti1–xAlxN solid solutions as a model system, it will be shown how polymorphic competition—tuned via the Al content x—governs the alloys’ plastic response under K-controlled loading. The results highlight the profound impact of atomic-scale plasticity on observable mechanical properties and suggest strategies for toughening ceramics through controlled manipulation of polymorphic transformations.

CD-3:IL20  Tailoring the Tribological Response of Amorphous Carbon Films by Alloying
F. MANGOLINI, C. EDWARDS, HSU-MING LIEN, N. MOLINA, The University of Texas at Austin, Austin, USA

Dopants and alloying elements are commonly introduced in amorphous carbon (a-C) thin-film materials to tailor the mechanical and tribological properties. While most studies have focused on doping and/or alloying a-C coatings with metals and metalloids, the introduction of rare-earth elements into the a-C matrix is largely unexplored. Here, the friction response of a-C films containing europium ([Eu] = (2.4±0.1) at.%) or gadolinium ([Gd] = (2.3±0.1) at.%) was evaluated as a function of applied normal load in open air and at room temperature. The friction results indicated that alloying a-C films with Gd or Eu leads to a reduction of the shear strength of the sliding interfaces. To shed light on the origin of the promising tribological properties of Eu- and Gd-alloyed a-C films, near-edge X-ray absorption fine structure (NEXAFS) spectromicroscopy measurements were performed. The surface-analytical results indicated that no stress-assisted sp3-to-sp2 rehybridization of carbon atoms was induced by the sliding process in the near-surface region of undoped a-C, while the amount of sp2-bonded carbon increased in Eu- and Gd-alloyed a-C films. Based on these results, a model is proposed for the effect of introduction of Gd and Eu into the a-C matrix on the resulting tribological response.

CD-3:IL21  Nanomechanical Simulations of Defective Ceramics via ML-powered Molecular Dynamics
CHUNHUI DU¹, SHUYAO LIN^1,2, D.G. SANGIOVANNI², P.H. MAYRHOFER¹, N. KOUTNA^1,2, ¹Institute of Materials Science and Technology, TU Wien, Vienna, Austria; ²Department of Physics, Chemistry, and Biology (IFM), Linköping University, Linköping, Sweden

In this contribution, we will exploit ML-powered molecular dynamics (MD) simulations to develop atomic scale understanding of paradigm boron-based ceramics, such as TiB2, under large mechanical strains. The chosen material systems represent common as well as novel coating materials, combining high hardness, excellent thermal and chemical stability, but low toughness–limiting their resistance to crack nucleation and propagation. We will illustrate that even simple point and planar defects, such as vacancies and antiphase boundaries, can profoundly impact mechanical properties, thus may be intentionally used to achieve desired response subject to application-relevant loading conditions. Specifically, we will focus on the intrinsic response to nanoindentation, arguably the most widely used mechanical test for hard ceramics. Training and validation strategies for machine learning force fields necessary to perform these complex nanoscale simulations will be discussed. Subsequently, the force fields will be employed to perform finite-temperature tensile, shear, and nanoindentation tests of TiB2−x structures, where the B sub-stoichiommetry is realized via disordered B vacancies, single- or double-planar defects previously reported in experiment. We will discuss trends in the predicted elastic constants, hardness, and other mechanical properties as well as the underlying deformation mechanisms from room up to elevated temperatures relevant for operational use of ceramics. Wherever relevant, MD predictions will be correlated with available experimental results.

CD-3:L22  High-temperature Friction and Wear Performance of Cr2AlC Coating
XUEJIN ZHANG, SHIBO LI, WEIWEI ZHANG, Center of Materials Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing, China

H13 hot work die steel is usually used as piercing plugs. During piercing operation, high temperature and large friction force often cause failure problems such as collapsed nose and steel sticking. Cr2AlC, as a ternary layered MAX phase, has outstanding high-temperature resistance and crack self-healing properties, etc. In addition, its coefficient of thermal expansion matches that of H13 steel. Therefore, choosing it as a coating on the H13 steel substrate is of great significance for improving the service life of piercing plugs. In this work, we investigated the high-temperature friction and wear properties of a Cr2AlC coating. A high-purity Cr2AlC coating was prepared on the H13 steel substrate by cold spraying technology. The friction coefficient of the coating remained stable at 0.4 under 1000 ℃ and 20 N load. The maximum wear depth of the coating was only 75 μm, which is less than 110 μm of the substrate. The wear rate of the coating was 14.08×10-6 mm3·N-1·m-1, lower than 21.53×10-6 mm3·N-1·m-1 for the substrate. The high-temperature resistance and wear resistance mechanisms of Cr2AlC were analyzed based on experimental results. These results provide theoretical guidance and technical support for the application of high-temperature wear-resistant MAX phase coatings.

CD-3:L23  Exploring the Mechanical Properties and Thermal Stability of Multicomponent and Multilayer Hard Coatings
YIN-YU CHANG^1,2, TSUNG-HUNG TSAI¹, HE-QIAN FENG¹, MIN-XIN SHI¹, ¹Department of Mechanical and Computer-Aided Engineering, National Formosa University, Yunlin, Taiwan; ²High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan

Recent advancements in TiAlN- and CrAlN-based multilayer coatings have opened new opportunities for enhancing performance under extreme operating conditions. To further improve these coatings, incorporating elements such as Si, Mo, Nb, and B into the coating systems- forming CrAl-X-N and TiAl-X-N has been shown to significantly enhance wear resistance and thermal stability. In this study, multicomponent and multilayer coatings combining Si, Mo, Nb, and B were fabricated using an electromagnetic-controlled cathodic arc ion plating method. High-temperature oxidation experiments revealed that oxidation rates strongly depend on film composition and microstructural features. Cutting performance tests on glass fiber–reinforced composites and SUS304 stainless steel demonstrated that the compositional gradient and multilayer architecture significantly influence both mechanical and cutting performance. The coatings exhibited high hardness (26 to 38 GPa), primarily attributed to grain refinement and nanoscale multilayer strengthening. Furthermore, enhanced oxidation resistance and secondary hardening at elevated temperatures suggest that these coatings are promising candidates for demanding high-temperature and wear-intensive industrial applications.

CD-3:IL24  Performance of Hardmetal Coatings at High Temperatures in Different Atmospheres
L.-M. BERGER, S. CONZE, K. GNAUCK, Fraunhofer IKTS, Dresden, Germany

High-temperature applications of hardmetal coatings for wear protection are connected with numerous challenges. In this study the behavior of structurally different Cr3C2-NiCr coatings and the influence of the Cr3C2/WC ratio in binary coating compositions deposited on a nickel-based alloy (2.4856) or a high-temperature steel (1.4828) was investigated. Heat treatments were conducted at temperatures ranging from 500 to 1000 °C for up to 32 days in various atmospheres (air, nitrogen, argon). The samples were extensively studied by FESEM and XRD in order to determine the stability of a certain coating-substrate combination, or the failure mechanism. Among the coating materials, only the composition 73WC-20-Cr3C2-7Ni was found to be not oxidation-resistant in air at temperatures above 500 °C at long term. The failure of Cr3C2-NiCr coatings at 900 °C is attributed to the formation of a SiO2 layer on the 1.4828 substrate, independent of the atmosphere. A sufficiently high WC content prevented delaminations. In case of the 2.4856 substrates, Cr2O3 layers formed at the substrate did not lead to coating delamination. High WC contents prevented the formation of the Cr2O3 layer.

CD-3:IL25  Exploring the Fabrication of High Entropy Alloy Nitride, Carbide, and Boride Thin Films for Protective Applications
JYH-WEI LEE^1,2,3,4, BIH-SHOW LOU^5,6, ¹Department of Materials Engineering, Ming Chi University of Technology, New Taipei, Taiwan; ²Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei, Taiwan; ³College of Engineering, Chang Gung University, Taoyuan, Taiwan; ⁴High Entropy Materials Center, National Tsing Hua University, Hsinchu, Taiwan; ⁵Chemistry Division, Center for General Education, Chang Gung University, Taoyuan, Taiwan; ⁶Department of Orthopaedic Surgery, New Taipei Municipal TuCheng Hospital, Chang Gung Memorial Hospital, Taiwan

Research on high entropy alloy (HEA) materials has attracted widespread attention worldwide since Prof. Yeh and co-workers first reported their pioneering work in 2004, marking the beginning of a new era in materials science. In particular, HEA thin films prepared by the magnetron sputtering technique have been extensively investigated for their outstanding corrosion resistance, mechanical strength, and wear resistance. In this study, TiZrNbTaFeN nitride, CrMoNbTiWC carbide, and (HfVTiZrW)B₂ boride thin films were fabricated using the high power impulse magnetron sputtering (HiPIMS) technique. The effects of nitrogen gas and acetylene gas flow ratios on the phase structure, chemical composition, mechanical properties, and corrosion resistance of TiZrNbTaFeN nitride and CrMoNbTiWC carbide thin films were systematically studied, respectively. For (HfVTiZrW)B₂ boride thin films, the effect of deposition temperature on phase structure, microstructure evolution, mechanical properties, and corrosion resistance was explored. The results demonstrate that by optimizing the deposition parameters, high hardness, superior wear resistance, and excellent anticorrosion performance can be achieved in these thin films, which show great potential for protective and functional applications.

Session CD-4 Protective coatings in oxidizing, high-temperature, and harsh environments

CD-4:IL26  Thermal Barrier Coatings on Components with Cooling Holes
R. VAßEN, IMD-2 Forschungszentrum Jülich GmbH, Jülich, Germany

Cooling holes are frequently used in thermally highly loaded parts of gas turbine components. Additive Layer Manufacturing (ALM) techniques have emerged as a promising method for the fabrication of more efficient cooling holes with sophisticated geometries. In this study, ALM button samples with and without cooling holes were coated with High-Velocity Oxygen Fuel (HVOF) CoNiCrAlY bond coats and partially Yttria-stabilized zirconia (YSZ) top coats. The top coats were prepared by either suspension plasma spraying (SPS) or atmospheric plasma spraying (APS), using non-90° spraying angles to avoid spraying directly into the cooling holes. Subsequent to this, the samples were exposed to thermal cycling in a furnace at 1100°C, with the objective of comparing their lifetimes and failure mechanisms. The lifetime results of the coatings were comparable for samples with and without cooling holes, as well as when using APS and SPS. An interpretation of the results with respect to the evolving stresses at the edge locations of the cooling holes will be given.

CD-4:L27  Unveiling the Phase Transformations under High Temperature and High Pressure of Boron Nitride system via Molecular Dynamics Simulation with Machine Learning Potential
SIYAN ZHANG, YIXIU LUO, LUCHAO SUN, JIEMIN WANG, JINGYANG WANG, Institute of Coating Technology for Hydrogen Gas Turbines, Liaoning Academy of Materials, Shenyang, China

Boron nitride (BN) is a highly versatile material system with well-characterized polymorphs that underpin its exceptional and tunable properties. To address limitations in experimental conditions while balancing efficiency and accuracy in conventional theoretical simulations, a deep potential for the BN system is developed using deep neural networks trained on ab initio calculation data. Validated through deep potential molecular dynamics (DPMD) simulations encompassing ground-state, high-temperature, and high-pressure properties, this DP facilitates accurate modeling of both strong B-N covalent interactions and weak van der Waals forces across crystalline, liquid, and amorphous phases of c-BN, h-BN, r-BN, and w-BN. In this context, DPMD simulations can provide atomic-level insights into pressure-induced and temperature-dependent phase transitions of h-BN and r-BN, accurately describing its stable phases and intermediate metastable phases. Notably, independent of temperature, metastable bct1W1 and bct2W1 phases act as intermediates during the h-BN to w-BN transition. Temperature, however, exerts distinct effects on transitions of r-BN, with high temperatures inducing orthogonal stacking in r-BN and thereby facilitating its transformation into highly twined c-BN.

CD-4:L28  On the Origin of Pitting Corrosion during Oxidation of Graphite Coated with Reaction Bonded SiC
C. SEIMETZ¹, F. MEIER², S. NEUMEIER², M. TREMPA¹, J. FRIEDRICH¹, ¹Fraunhofer IISB, Erlangen, Germany; ²Friedrich-Alexander-Universität Erlangen-Nürnberg, Materials Science & Engineering, Institute MSE I, Erlangen, Germany

Due to its flexibility of machining, high purity and high temperature resistance, graphite is a widely used material for reactor components in a large variety of applications. However, in oxidizing environments, pure graphite degrades. To mitigate this, protective SiC-based coatings can be applied to the graphite, as SiC remains stable in oxidizing conditions by forming a SiO2 layer. One cost-effective approach is the formation of a reaction bonded (RB) SiC layer at the component surfaces by bringing them into contact with Si species. To investigate the oxidation resistance of such RB-SiC coatings, which are developed at Fraunhofer IISB, cyclic oxidation experiments are carried out at 1100°C under a dynamic flow of synthetic air. Between the individual oxidation cycles, non-destructive computed tomography scans are used to locate and pursue pitting corrosion of the coating and the graphite. Additionally, the sites of corrosion are then analyzed by SEM to gain insights into the degradation mechanisms. Hereby, EDS analysis revealed traces of contaminants at the sample surface that could be linked to the locations of the pitting corrosion and let assume that some chemical reaction hinders the SiC formation. Finally, strategies optimizing the coating performance will be discussed.

CD-4:L29  Growing Cu Thin Films to Single-crystal with a High Oxidation Resistance
SU JAE KIM¹, YOUNG-HOON KIM^2,3, YOUNG-MIN KIM², SEONG-GON KIM⁴, SE-YOUNG JEONG^5,6, ¹Crystal Bank Research Institute, Pusan National University, Busan, Republic of Korea; ²Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea; ³Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA; ⁴Department of Physics and Astronomy, Mississippi State University, Mississippi State, MS, USA; ⁵Department of Optics and Mechatronics Engineering, Engineering Research Center for Color-Modulated Extra-Sensory Perception Technology, Pusan National University, Busan, Korea; ⁶Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea

It has long been considered impossible to grow thin films in a single-crystal form. This is mainly because, unlike conventional bulk crystal growth using a seed, thin film growth involves numerous nucleation sites, making single-crystal thin film difficult to achieve. In particular, the sputtering method is known to be advantageous for large-area growth, but the crystalline quality is typically very poor. In this study, the atomic sputtering epitaxy (ASE) technique is introduced, which overcomes the fundamental limitations of conventional sputtering and enables the growth of thin films with single-crystal quality without grain boundaries. Copper is easily oxidized by oxygen. However, when the thin films possess a flat surface, oxidation is significantly suppressed, making it highly suitable as a substrate for growing 2D materials such as graphene or hBN. Moreover, when single-crystal copper is intentionally oxidized, the oxidation can be controlled like a vector quantity, and depending on the thickness of the oxidized layer, a wide range of vivid colors can be obtained. On the other hand, we also introduce a novel method that keeps copper unoxidized even at temperatures above 300 °C while maintaining its excellent conductivity.

CD-4:IL30  Oxidation and High Temperature Resilient Coatings for Aerospace Tribological Applications
A.A. VOEVODIN, Department of Materials Science and Engineering University of North Texas, Denton, TX, USA

Tribological contact surfaces, which can operate in oxidative and high temperature environments are of a practical importance for aerospace applications, where extremes of temperature, pressure, and environments limit liquid lubrication and requires solid lubricants and robust wear-protective coatings. This presentation discusses surface engineering technologies for preparing self-adaptive coatings and contact surfaces, called “chameleon”, for friction and wear reduction under oxidative environments and high temperatures. The examples include: i) composite coatings made of hard nano-crystalline carbide, nitride and oxide matrices with nano-sized inclusions of solid lubricants and transition metals capable of forming high-temperature lubricating oxides, and ii) duplex coatings based on plasma electrolytic oxidation with controlled surface morphology and embedded adaptive lubricants. In all these approaches, the lubricating materials are self-released from engineered reservoirs or formed in-operando by tribological surface interaction with the environment. This facilitates adaptive chemical, phase and nanostructure changes in contact interfaces to continuously reduce friction energy losses and wear at extreme and variable conditions.

CD-4:L31  The Role of Oxides formation on Oxidation Resistance of the Pack Cementation Coated Refractory High Entropy Alloys and Nb Alloys
JOONSIK PARK, Hanbat National University, Daejeon, South Korea

The Mo and Nb components, which are essential constituents of many high-entropy alloys, are highly susceptible to oxidation at elevated temperatures. For example, molybdenum (Mo) tends to sublimate at approximately 500 °C, whereas niobium (Nb) forms porous, non-protective oxides under similar conditions. These behaviors highlight the necessity of protective strategies for alloys containing Mo and/or Nb during high-temperature exposure in air. In this study, pack cementation coatings were employed to protect the surfaces of refractory high-temperature alloys containing Mo and Nb. When silicon (Si) or boron (B) powders were used in the coating process, silicides or borides formed on the alloy surfaces. Several case studies, including alloys from the AlMoNbTaTiZr system, were investigated. Notably, the coatings developed nanograined layers, which contributed to improved oxidation resistance. Furthermore, the oxidation behavior of a representative Nb-based alloy substrate was systematically examined, and the post-coating performance was analyzed in terms of phase transformations and reaction kinetics.

CD-4:L32  Study on Interface Failure of Rare Earth Disilicate Environmental Barrier Coatings by FEM Simulation
JIEMIN WANG, J.Y. WANG, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China; Q. CHEN, School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, China

Rare earth disilicate (RE₂Si₂O₇) environmental barrier coatings (EBCs) have attracted significant attention when applied to SiCf/SiC ceramic matrix composites (CMCs) due to their excellent corrosion resistance and good thermal compatibility with SiC materials. To enhance the bonding with the CMC substrate, a Si bonding layer is typically introduced between the RE₂Si₂O₇ surface layer and the CMC substrate, forming a RE₂Si₂O₇/Si bilayer structure. During long-term service in a combustion environment, the Si bonding layer is slowly oxidized, forming a thermally grown oxide (TGO) layer at the RE₂Si₂O₇/Si interface. Due to thermal mismatch and volume changes, significant stress is generated at the interface, leading to interface debonding, which is the primary failure mode of RE₂Si₂O₇/Si bilayer EBCs. In this work, finite element (FEM) numerical simulation is employed to study the interface cracking process under the coupling conditions of thermal cycling and water vapor corrosion. The key factors such as crack initiation location, propagation direction, and the cumulative interface damage evolution during thermal cycling are systematically analyzed, aiming to provide theoretical guidance for designing rare earth silicate EBCs with long lifespans.

CD-4:L33  Oxidation Induced Decomposition and Pore Formation in Cr₂AlC Coatings Revealed by Correlative Tomography
D.J. RAMESH, S.A. SALMAN, J. M. SCHNEIDER, Materials Chemistry, RWTH Aachen University, Aachen, North Rhine Westphalia, Germany

Decomposition and pore formation during oxidation of Cr2AlC coatings with equiaxed and columnar grains were investigated using mass‐balance calculations. While Cr7C3 formed in both coating morphologies, pore formation occurred only in columnar coatings. The volume of Cr7C3 forming during oxidation was estimated assuming: (i) Al deintercalation enables oxide scale and Al-O-C-N precipitate formation, leading to complete transformation Al depleted Cr2AlC into Cr7C3 with no partially deintercalated Cr2AlC remaining; (ii) all phases exhibit theoretical densities; and (iii) scale formation prevents Al volatilization. In equiaxed coatings, theoretically estimated carbide volume matched the measured volume within 3±3 %, validating the Al deintercalation driven carbide formation not. The larger molar volume of Cr2AlC compared to Cr7C3 should result in pore formation during decomposition. The lack of pores was rationalized by a compensating coating thickness shrinkage. In columnar coatings, the estimated Cr7C3 volume exceeded the measured value by 22 ± 4%, which is likely due to partial Al deintercalation from Cr2AlC in addition to Cr7C3 formation. The estimated pore volume was 13–16 % smaller than measured, plausibly due to clustering of preexisting pores and vacancies.

CD-4:IL34  Metal-carbide Composites through Solution Processing
G. WESTIN, S. NAIM KATEA, T.K. SAHU, M. EK, Uppsala University, Uppsala, Sweden; P. GRUBER, F. AKHTAR, Luleå Technical University, Luleå, Sweden

Hard, durable and corrosion resistant materials are of great importance for a large number of key technological areas including metal machining, drilling, and next generation lead cooled nuclear reactors. The requirements differs for these areas, especially regarding corrosion resistance where oxygen and water are the all dominating corroding species for almost all areas, but for the Generation IV lead cooled reactors operating at 500-800 oC, the corrosive medium is molten lead where transition metal dissolution and wear from fast moving hot lead is been seen as the main damaging factor. The impellers pumping molten lead is one of the key components and preferably should resist damage from metal dissolution, wear and oxidation preferably for a duration of 16 years. In this talk, different solution based techniques to prepare WC-Ni/Fe/Co composites with controlled WC grain sizes from 0.5 to 60 m size with a binder metal content down to levels making them “binder-less” with uniquely high hardness for such composites. In order to completely inhibit oxidation from low ppm levels of oxygen, metal carbide composites with Zr, Nb, and Ti having high hardness while forming dense hard oxide coatings will be discussed.

CD-4:IL35  Protective Ceramic Coatings in Nanomaterial Advancements via Hybrid Aerosol Deposition
M. SHAHIEN, Integrated Research Center for Resilient Infrastructure, National Institute of Advanced Industrial Science and Technology, AIST, Japan

Hybrid Aerosol Deposition (HAD) is an advanced coating technology that merges the benefits of traditional thermal spray and aerosol deposition (AD) methods. By utilizing mesoplasma, HAD activates the surfaces of ceramic particles without melting them, enabling the deposition of thick ceramic coatings with enhanced deposition rates and three-dimensional coverage. This method allows for precise control over coating porosity, enabling the tailoring of material properties to meet specific application requirements. Its versatility not only improves the performance of ceramic coatings in conventional uses but also extends their applicability to new and demanding environments, addressing broader industrial and societal needs. HAD offers a powerful, room-temperature coating solution that combines high adhesion, excellent coverage, and scalability. In addition, it is particularly suitable for materials previously inaccessible through conventional techniques, such as those with covalent bonding structures. This study introduces the principles of the HAD process and presents recent advancements in its application for producing dense, protective ceramic coatings on a variety of substrates, including metals, ceramics.

CD-4:L36  Phase Formation and Oxidation Behavior of Sputtered Cr2AlB2 Thin Films
S.A. SALMAN, D.J. RAMESH, J.M. SCHNEIDER, Materials Chemistry, RWTH Aachen University, Aachen, North-Rhine Westphalia, Germany

Cr2AlB2 is a candidate for high-temperature protective coatings due to its ability to form passivating Al-based oxides. Oxidation of Cr2AlB2 coatings has not been reported, likely because phase-pure synthesis demands stringent compositional control. We demonstrate the deposition of phase-pure Cr2AlB2 on α-Al2O3 and investigate its oxidation behavior from 700 – 1200 °C. Below 1000 °C, oxidation yields a crystalline bilayer scale with outer chromia and an inner aluminoborate. The chromia thickness is time-independent, consistent with formation during the transient heating-up stage. Scale-growth kinetics show sub-parabolic thickening of the aluminoborate, indicating its passivating nature. The underlying film develops porosity along column boundaries but remains largely intact until ~900 °C, where selective Al oxidation drives local CrB formation at the scale interface. At ≥1000 °C, a dense, equiaxed α-Al2O3 scale forms while Cr2AlB2 thermally decomposes to CrB + Al. Temperature-dependent free-energy trends from DFT lattice-dynamics calculations show decreasing relative stability of Cr2AlB2 with temperature, rationalizing the spontaneity of decomposition. The oxidation kinetics of Cr2AlB2 at 1000 °C are similar to Cr2AlC coatings, as both materials form protective α-Al2O3 scales.

CD-4:IL37  High-temperature Resistant Multielement Coatings: Properties and Opportunities
P. ZEMAN, Department of Physics and NTIS – European Centre of Excellence, University of West Bohemia in Pilsen, Czechia

Multielement systems enable the design and development of advanced or novel materials with unique properties and multiple functionalities by precisely controlling their chemical composition, structure, and microstructure. Among these, quaternary and quinary ceramic coatings stand out promising candidates for high-temperature applications, demonstrating exceptional performance at temperatures exceeding 1000°C. When combining excellent oxidation resistance with the thermal stability of high optical transparency, these coatings can serve as high-temperature passive protection of optical and optoelectronic devices under extreme conditions. Alternatively, the combination of high oxidation resistance and thermally stable electrical conductivity makes them suitable for capacitive pressure, vibration, and tip clearance sensors operating in a severe oxidation environment. One of the multielement systems addressing both variants is the Hf-B-Si-C-N system, which can be further enriched with Y or Ho. The talk will present amorphous coatings from this system synthesized using reactive magnetron sputtering. Depending on composition, the coatings exhibited either electrical conductivity or optical transparency while maintaining sufficient hardness and superior oxidation resistance up to 1600°C.

CD-4:IL38  From Process to Performance: Tailoring Coatings for Harsh Service Conditions
CHONGCHONG TANG, K. KHANCHYCH, C. SCHROER, M. STÜBER, B. GORR, Institute for Applied Materials (IAM-AWP), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

Improving efficiency and reliability in energy systems requires coatings capable of withstanding extreme environments. In this work, two classes of high-performance coatings, MAX phases and refractory compositionally complex alloys (RCCAs), were developed and optimized. Using nanostructured multilayer precursors deposited by magnetron sputtering, phase-pure Al2O3-forming MAX coatings with basal-plane orientation and controlled microstructures were synthesized at reduced temperatures. In parallel, Ta–Mo–Cr–Ti–Al RCCA coatings were produced with compositions tailored for balanced oxidation resistance and mechanical stability. By tuning deposition parameters, dense coatings closely matching bulk alloys were achieved. Both coating systems show excellent high-temperature corrosion resistance in various environments, including air, steam, and liquid metals. MAX coatings form protective alumina scales, while RCCA coatings develop complex (Cr,Ta)-rich rutile layers. These results demonstrate how microstructural design and compositional control enable next-generation coatings for extreme-service applications.

Symposium CD

Cimtec 2026