The hardness enhancement technique for detonation gun coating

Throughout the globe lot of research works are going on in order to improve the surface wear resistance of the different industrial materials. For that reason the surface coating techniques become popular. The detonation gun (d-gun) spraying is one of the most advanced thermal spray variants for depositing high quality wear resistant coatings. Of all the ceramic materials that can be D-gun sprayed, alumina (Al2O3) is the most widely established and these coatings have already gained industrial acceptance for diverse applications. The present study deals with a statistical design of experimental study of the D-gun spraying of Al2O3 powder. Coating experiments were conducted, using a Taguchi L4 design parametric study, to optimize the D-gun spray process parameters. Three selected important spraying parameters were considered in their upper and lower levels of the predefined range according to the test matrix, in order to display the range of processing conditions and their effect on the coating quality. Image analysis and micro-hardness testing was used for characterization. Coating qualities are discussed with respect to surface hardness and microstructure. The attributes of the coatings are correlated with the changes in operating parameters and their relative importance and contribution ratios to overall variance are calculated.