Tribological characteristics of n-(GO/WC-10Co-4Cr) HVOF coatings under biolubricant conditions

Abstract

The proposed work deals with the tribological studies of thermal spray coated nano ceramic composite materials (GO/WC-10Co-4Cr) under the presence of jojoba oil based bio lubricant. Flame spray coating was carried out on AA6061 discs with coating thickness of (50–150 µm) by different concentrations of (GO) graphene oxide (0.075–1%)wt. + nano mixture of WC-10Co-4Cr powder. Tribology tests were conducted on the coated disc samples using pin on disc apparatus as per ASTM G99-05 for various test parameters namely applied load (50N–150N), disc rotational speed (1–10 m s−1), % vol. concentration of Jojoba oil (0–30%). Results obtained from the tribo tests clarifies that the 0.085 GO/WC-10Co-4Cr composite coatings with 150µm exhibited lower friction coefficient of 0.1854, lesser wear rate of 2.25×10−5 mm3 Nm−1 compared with that of the uncoated specimens. SEM analysis portrays the formation of IMC'S (aluminium carbonate Al2(CO3)3 and chromate Al2(CrO4)3)to strengthen the boundary regime against oxidative wear.