Tribo-behaviour of APS and HVOF sprayed WC–Cr₃C₂–Ni coatings for gears

ABSTRACT

The tungsten-carbide coatings could be employed to minimise failures of gears due to excessive wear in hostile operating atmospheres. In this work, WC-Cr₃C₂-Ni powder was deposited on the SS 316L substrate using APS and HVOF processes. The deposited coatings were characterised and investigated for the effects of dissimilar counter bodies. The unidirectional sliding experiments were conducted on the ball-on-disc tribometer (ASTM G99-95a). The variable contact pressure was applied to simulate the tangible effect of contact stress variation during the dry sliding in the gears. The wear mechanisms depicted that the wear is in the mild regime and better durability of both coatings. The results of tribo-testing and analysis of results by ANOVA confirmed that contact pressure and hardness of counter body are significant factors influencing friction and wear. Furthermore, the relation between contact surface temperature and adhesion of debris to the surface has been studied.

KEYWORDS:

• WC–Cr₃C₂–Ni
• abrasive wear
• gears
• APS
• HVOF

Acknowledgements

The authors are grateful to VJTI, Mumbai and thankful to IIT Bombay, India, for availing the testing facilities such as SEM, EDX, XRD, nano-indentation and non-contact profilometer. This research work is not supported with any financial grant from public or commercial funding agencies.

Disclosure statement

No potential conflict of interest was reported by the author(s).