Tribological Performance of Stellite 6/TiN Composite Coatings on Austenitic Stainless Steel

To enhance the quality and longevity of valve sealing surfaces, this study fabricated the Stellite 6/TiN composite coatings on F347 austenitic stainless steel. The process involved a plasma transferred arc (PTA) of Stellite 6 coating onto the substrate followed by physical vapor deposition (PVD) of a TiN coating onto the Stellite 6 layer. Mechanical testing revealed that the composite coatings achieved high hardness (~2110 HV), excellent adhesion (critical load Lc2 ~74 N), and superior wear resistance versus uncoated steel and single-layer Stellite 6. At 500 °C, the composite reduced wear volume by 97.2% compared to the uncoated substrate. Wear mechanisms for the Stellite 6 and composite coatings at high temperatures were elucidated, highlighting the role of Stellite 6/TiN composite coatings in enhancing tribological performance.