Tribological behavior of TiB2―TiC―Al2O3 composite coating synthesized by combined SHS and laser technology

Multi-phase ceramic composite coatings of TiB2-TiC-Al2O3 with an intermetallic phase of TiAl3 were developed through the self-propagating high-temperature synthesis reaction of TiO2, B4C and Al powders. A high power diode laser was used to coat the products onto AISI 1020 steel substrate. The developed composite coatings were characterised using XRD, FESEM and micro-hardness measurement. The dry sliding wear behaviour of the composite coating was assessed using a ball-on-disc tribometer at various loads (9.8, 19.6, 29.4 and 39.2 N) and sliding speeds (0.052, 0.104 and 0.156 m/s). The wear rate increased and the friction coefficient decreased with increasing normal load. The laser power and laser scan speed used to produce the coatings and the sliding speeds used during ball-on-disc tests did not significantly affect the tribological performance of the coating. However, at high normal loads and high sliding speeds the coatings exhibited rapid wear and suffered from partial removal from the substrate.