Effect of application parameters in Ni-Cr-B-Fe-Si coatings obtained by flame spray
ABSTRACT Surface damage of components in service is an issue of great industrial interest because of the costs associated to the replacement of certain critical components. There are several techniques to generate coatings, which provide increased resistance to a particular type of surface damage. In this way, it is achieved surface protection to different solicitation such as temperature, abrasion, erosion, corrosion, etc., obtaining an extension of the useful life. Thermal spray techniques are used today for the production of coatings with thicknesses between 100 and 2000 microns. One of the most commonly used because of its simplicity and low cost is the Flame Spray (FS). The projection parameters and refusion conditions can significantly affect the characteristics of the obtained coating. Nickel base alloys are used in coatings subjected to wear, corrosion and/or high temperature. The aim of this study was to analyze the effect of projection conditions on the microstructural characteristics and wear resistance of coatings of a Ni-Cr-Fe-B-Si alloy obtained by FS. For this purpose on steel carbon specimens, coating were obtained by varying the distance of application and the number of layers. Refuse in a furnace at 1160°C for 10 minutes was also apply. On coated samples the defect level, thickness and microstructure were analyzed. Vickers microhardness was determined and rubber wheel abrasion test ASTM G-65 type were performed. Obtaining a decrease in defect levels and better wear performance with decreasing distance of application and increase the number of layers.