Investigation of structural and tribological properties of TiW/TiWSi/TiWSiN graded composite coatings deposited by magnetron sputtering method

In this work, TiW/TiWSi/TiWSiN graded-composite coatings were deposited on AISI 52100 steel substrates by RF magnetron sputtering and subsequently annealed at 600°C, 700°C, 800°C, and 900°C. Structural characterization was performed using SEM, EDS, XRD, and XPS. While the as-deposited films were largely amorphous, post-annealing treatments prompted the emergence of TiN crystalline phases with (111), (200), and (220) orientations, as evidenced by both XRD and XPS analyses. Mechanical and tribological properties were assessed through microhardness testing, friction‐coefficient measurements, reciprocating wear trials, and progressive‐load scratch adhesion tests. The 600°C-annealed coatings exhibited the highest hardness (8.5 GPa), the lowest friction coefficient (0.13), and the minimal wear rate (2.16x10-6 mm3/(N·m)). In scratch testing, only the A-600 coatings retained their integrity, whereas higher‐temperature samples showed microcracks and interfacial weakening. These results confirm that carefully optimized post-deposition annealing markedly improves the hardness, wear resistance, and adhesion of TiW/TiWSi/TiWSiN coatings, and they provide a practical framework for their deployment in demanding, wear-intensive applications.