Structural and mechanical properties of magnetron sputtered (NbxMo1-x)C thin films

• Published in: Vacuum Vol. 224; p. 113146
• Main Authors: Osinger, Barbara, Donzel-Gargand, Olivier, Fritze, Stefan, Jansson, Ulf, Lewin, Erik
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2024
• Subjects: Ceramic coating; Chemistry with specialization in Materials Chemistry; Kemi med inriktning mot materialkemi; Magnetron sputtering; Mechanical properties; Transition metal carbides; Mechanical properties; Magnetron sputtering; Ceramic coating
• ISSN: 0042-207X; 1879-2715; 1879-2715
• DOI: 10.1016/j.vacuum.2024.113146

While transition metal carbides (TMCs) exhibit favourable mechanical properties, alloying according to the valence electron concentration (VEC) has the potential to further enhance the properties of these hard but inherently brittle materials. This study investigates the influence of alloying on the microstructure and mechanical properties of (NbxMo1-x)C carbide films, including binary references and ternary compositions with varying metal ratios (x between 0.35 and 0.53). Furthermore, the influence of various substrate materials is studied by comparing films deposited on Al2O3, MgO and SiO2. All films exhibit a NaCl-type carbide structure and X-ray photoelectron spectroscopy revealed the presence of small amounts of an additional amorphous carbon (a-C) phase. Hardness values around 20 ± 2 GPa were obtained for the films on Al2O3 and MgO, whereas a reduced hardness of 11 ± 1 GPa was observed for the films on SiO2 which is attributed to larger crystallite size and more polycrystalline structure. Overall no clear trend as a function of composition can be noted, indicating that microstructure effects dominate the mechanical properties in this study overshadowing the effect of varying the metal content.
•The structure and mechanical properties in binary and ternary magnetron sputtered (NbxMo1-x)C are studied.•The films consist mainly of nanocrystalline NaCl-type (NbxMo1-x)C phase with 3‑9 % amorphous carbon (a-C).•No trend of the mechanical properties as a function of the varied metal composition is observed.•Experiments of films on different substrate materials underline the importance of microstructural effects.