Analysis of factors influencing dry sliding wear behaviour of laser remelted plasma sprayed mo coating using response surface methodology

Plasma spraying is a process widely used to fabricate wear resistant coatings. However, various problems are associated with plasma spraying out of which poor bonding strength between the coating and the substrate and the high porosity in the as sprayed coatings are of major concern. In order to eliminate these problems and enhance wear performance, the laser remelting process has been used. The laser remelting of plasma sprayed Mo coatings alters the wear mechanism and improves the wear resistance. The wear mechanism and wear volume loss depend on the applied load, sliding speed and sliding distance. Hence, an effort has been made to investigate the effect of process parameters on volume loss using Response Surface Methodology (RSM) based mathematical models. The experiments were planned as per Central Composite Design (CCD). The investigations revealed that the applied load was the most dominant factor affecting the volume loss of the coating. The sliding speed, sliding distance and interaction effects were considered as the next important parameters influencing the volume loss. The investigation also reveals that, the wear volume loss depends on two wear mechanisms, one being the formations of grooves along surface tribo films and other being fracture of splats with delamination of the coating.