Study on the formation of interlayer in a coated sample

Abstract

Coating is physically bonded with substrate by adherence. So, on successful formation of adherence between coating and substrate, the surface engineering components can works successfully for a longer period of time. So, it is very important to study the bond formation between coating substrate. It is difficult to study the interlayer formation of a coated sample due to low coating thickness. The aim of the present work is to study the interlayer formation between steel substrate developed on the top of it, and a coating comprising of SiC, TiB2, and TiN. The study of interlayer can be done in both direct and indirect methods. In the direct approach, the interface region between the coating and substrate needs to be reached by removing the top part of the coating by means of grinding and polishing. This is difficult in case the interlayer is wavy, grinding and polishing of the top part of coating may actually remove some part of interlayer and expose the substrate. This hampers the study. The indirect methods involve studying and sensing properties of the coating, but it is heavily dependent on interpretations.The study of interlayer can be done in both direct and indirect methods. In the direct approach, the interface region between the coating and substrate needs to be reached by removing the top part of the coating by means of grinding and polishing. This is difficult in case the interlayer is wavy, grinding and polishing of the top part of coating may actually remove some part of interlayer and expose the substrate. This hampers the study. The indirect methods involve studying and sensing properties of the coating, but it is heavily dependent on interpretations.To study the interlayer of coating and underlying substrate, a metal matrix composite (MMC) is prepared in the powder metallurgical route. In the present work the MMC is prepared by different weight proportion of ceramic powder blend mixed to steel powder. The effect of different parameters such as compaction pressure and soaking time has been studied on composite.For evaluation of physical and mechanical properties of MMC, physical characterization such as Optical microscopy, x-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM), mechanical characterization such as, scratch hardness test, fracture toughness test, friction and wear test are performed.It is observed form the experiment that mechanical and tribological properties of MMC is optimum at 30wt.% of ceramic in steel matrix and it is also noticed that at compaction pressure 960 MPa and soaking time 30 min MMC shows optimum mechanical and tribological properties.