Microstructure, surface topography and sliding wear behaviour of titanium based coating on AISI 1040 steel by magnetron sputtering

In the present study, 2% B4C reinforced with Ti-6Al-4V composite coatings on AISI 1040 steel plates were coated using magnetron sputtering. The microstructure and surface morphologies of the coated specimen were analyzed using SEM, XRD, EDS and AFM. The uniform coating thickness of 75 nm and 110 nm on smooth surfaces have been obtained for 0.5 h and 1 h coating time respectively. Under the normal load of 2 N and 3 N, Ti-Al-V-B4C coatings wear analysis were performed and resulted in excellent wear rate with lower coefficient of friction. Ti-Al-V-B4C thin film shows the nano hardness value of 7.2 GPa and 9.7 GPa for 0.5 h and 1 h coating time and elastic modulus of 204 GPa. The surface roughness (Ra) of 0.5 h and 1 h coating are 3.393 nm and 17.433 nm respectively. The addition of B4C particles reinforced Ti-Al-V composite coatings showed enhanced nano hardness and improved the wear resistance with decrease in the coefficient of friction. The amount of heat generated during wear test has been calculated. Ti-Al-V-B4C composite coatings were exposed to lowest wear rates among all loading conditions and thus signifying that it could be a promising alternative to other hard coatings.