Pavel Souček

CrHfMoTaW–N high-entropy nitride thin films were deposited by reactive direct-current (DC) magnetron sputtering and reactive High Power Impulse Magnetron Sputtering (HiPIMS) at ambient temperature and at elevated temperature of 580°C. The influence of HiPIMS pulse parameters, nitrogen flow, deposition mode, and temperature on the phase evolution, microstructure, and mechanical properties of the thin films was systematically investigated. Non-reactive HiPIMS experiments showed that increasing pulse length reduced the effective bombardment while enhancing the contribution of ionised sputtered metal species, leading to phase separation at excessively long pulses. In contrast, increasing the pulse peak current significantly increased the bom- bardment, resulting in denser thin films and modified crystallographic texture. Based on these results, a pulse length of 20 μs and a peak current of 20 A were selected for the reactive depositions. Reactive depositions revealed a strong interplay between thermodynamic effects governed by temperature and kinetic effects governed by ion and neutral bombardment. Increasing nitrogen flow induced a phase transition from metallic bcc structures to fcc nitride phases. Elevated temperature together with high bombardment delayed the bcc–fcc transition and promoted crystallisation and grain growth while also promoting renucleation, and strongly influencing defect formation and crystallite stability. The results further showed that the fcc CrHfMoTaW–N phase is stabilised by nitrogen vacancies. Excessive nitrogen incorporation in ambient-temperature HiPIMS thin films promoted defect formation and limited crystallite growth, while lower nitrogen contents in thin films deposited at elevated temperature enabled continued crystallite growth due to retention of stabilising vacancies. Compared to DC sputtering, HiPIMS deposition resulted in significantly improved mechanical properties, with hardness increases of up to ∼60 % and markedly higher elastic modulus values. The superior properties were attributed to denser microstructure, enhanced crystallinity and larger crystallite size associated with energetic particle bombardment. The results demonstrate that both thermodynamics and ion-bombardment- driven kinetics play essential roles in the formation of refractory high-entropy nitride thin films. Control over both effects enables tailoring of the microstructure, phase composition, and mechanical performance of CrHfMoTaW–N thin films, while HiPIMS represents a highly effective approach for preparing dense and mechanically enhanced refractory high-entropy nitride thin films.

Thin film metallic glasses (TFMGs) are promising materials with significant application potential in electronics, optics, and medicine. However, their industrial use is often limited by low glass transition temperatures and relatively low hardness, leading to insufficient abrasion resistance. W‐based TFMGs show promise due to their high hardness, Young's modulus, and thermal stability. This article compares two coatings from the W–Ni–B and W–Zr–B TFMG systems, prepared using physical vapor deposition magnetron sputtering. These coatings are suitable for industrial applications requiring low surface free energy (SFE), low surface roughness, and good toughness, where tools and parts face various types of wear. Mechanical properties were measured using nanoindentation, and the structure was characterized by X‐ray diffraction. The coatings' fracture characteristics and crack resistance were examined using scanning electron microscopy. SFE was measured and used to calculate theoretical adhesion work with common polymeric materials. Tribological properties, including friction coefficient waveforms, were also investigated. Both TFMG systems exhibited hardness and elastic modulus comparable to current nitride coatings, with much lower SFE, high interfacial adhesion, and internal cohesion, along with a low coefficient of friction. These properties make them highly promising for industrial applications.