EFFECT OF SURFACE PROFILE OF MILD STEEL SUBSTRATE UPON ADHESION STRENGTH OF WC-11%CO FLAME SPRAY COATING

Improving surface properties especially high wear and impact resistance is always an existing challenge for automotive, aerospace, defense and agriculture industries etc. Surface engineering has developed various processes and methods to encounter this problem using plasma spray, electric arc, HVOF, PVD and flame spray etc. Amongst them flame spray technique has its own features to produce cermet coatings on steel substrates. In the present study, behavior of WC-11%Co coatings deposited on Mild Steel by means of flame spray process has been studied. It was found that surface roughness of substrate plays a vital role in the adhesion of such type of coatings. Therefore, different surface roughness profiles on substrate were generated by blasting sand and steel grits of various sizes. Surface profilometer was used to evaluate the surface roughness of substrates while the adhesion strength of flame spray coatings was determined by Pull test. SEM/EDX was used to study the morphology of flame spray coated samples and hardness was measured by micro-Vickers hardness tester. The results illustrate the optimum values of surface roughness to achieve better properties of WC-11%Co coatings for various engineering applications