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

## TL;DR

A new composite coating on stainless steel significantly reduces high-temperature wear, improving valve sealing performance.

## Contribution

A Stellite 6/TiN composite coating is developed to achieve superior high-temperature wear resistance.

## Key findings

- The composite coating reduces wear volume by 97.2% at 500 °C compared to uncoated steel.
- The coating achieves high hardness (~2110 HV) and excellent adhesion (Lc2 ~74 N).
- Oxide-glaze formation stabilizes friction, while oxidation-induced spallation affects wear mechanisms.

## Abstract

What are the main findings?
A Stellite 6/TiN composite coating is engineered on F347 stainless steel via plasma transferred arc cladding + PVD, enabling a property-gradient architecture for valve sealing applications.The coating system achieves outstanding high-temperature wear protection, reducing wear volume by 97.2% vs. uncoated F347 at 500 °C.

A Stellite 6/TiN composite coating is engineered on F347 stainless steel via plasma transferred arc cladding + PVD, enabling a property-gradient architecture for valve sealing applications.

The coating system achieves outstanding high-temperature wear protection, reducing wear volume by 97.2% vs. uncoated F347 at 500 °C.

What is the implication of the main finding?
The revealed wear mechanisms indicate that oxide-glaze formation stabilizes Stellite 6 friction, whereas oxidation-induced spallation in Stellite 6/TiN can accelerate combined abrasive/oxidative wear at 500 °C, guiding optimization of TiN design and oxidation resistance.

The revealed wear mechanisms indicate that oxide-glaze formation stabilizes Stellite 6 friction, whereas oxidation-induced spallation in Stellite 6/TiN can accelerate combined abrasive/oxidative wear at 500 °C, guiding optimization of TiN design and oxidation resistance.

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.