A comparative study of the tribological performances of laser clad TiB2–TiC–Al2O3 composite coatings on AISI 1020 and AISI 304 substrates

In this work, an investigation has been carried out to study the effects of the choice of substrate material on the tribological performance of TiB2–TiC–Al2O3 composite coating developed by laser cladding. The coatings have been deposited employing different laser scan speeds on AISI 1020 mild steel and AISI 304 stainless steel substrates using pre-placed precursor powder mixture of TiO2 Al and B4C. The coatings are characterized by using XRD, FESEM, micro-hardness measurement and tribological tests. The dry sliding wear behavior of the coating is assessed by using ball-on-disc tribometer at various normal loads (9.8, 19.6, 29.4 and 39.2 N) in order to experimentally determine the effects of applied normal load on the composite coatings developed on the two different steel substrates. Average wear rates of the coatings developed on AISI 1020 steel are higher than those of the coatings developed on AISI 304 steel for similar applied load. Coefficient of friction does not have a significant dependence on the choice of substrate material. Difference in the values of thermal conductivity of the two steel substrate materials is considered to have a significant effect on the microstructure and tribological performance of the coatings.