Development of Self-lubricating Nickel Based Composite Clad using Microwave Heating in Improving Resistance to Wear at Elevated Temperatures

This paper reports on a study of the high-temperature tribological performance of self-lubricating nickel-based composite clad. A porous and crack free clad containing matrix, reinforcement, and lubricant phase is developed on titanium 31 alloy using microwave irradiation. The microstructure of both NiCrSiB/WC and NiCrSiB/WC/Ag/BaF₂ clad revealed very good metallurgical bonding with the substrate. The average microhardness of NiCrSiB/WC and NiCrSiB/WC/Ag/BaF₂ clad is 710.58 HV and 650.25 HV respectively, is comparatively higher than the titanium 31 substrate (320 HV). The addition of Ag and BaF₂ solid lubricants in the clad endowing clad to operate at a broad temperature range. Compared with the NiCrSiB/WC clad, solid lubricant encapsulate clad has shown very low friction coefficient and wear rates. The sliding wear characteristics of the clad were investigated by varying load and temperatures. The results revealed that oxide phases (NiO and Cr₃O) and lubricant phases (Ag and BaWO₄) formed at low and high temperatures are adequate to reduce delamination and material loss.