Development and Characterization of Ni-YSZ Coating on Stainless Steel by HVOF Process

Abstract

Abstract-The objective of this study is to deposit oxide based cermet coating i.e. Nickel -yttria stabilized zirconia, Ni-YSZ on stainless steel (SS) by HVOF process. The YSZ content in the coating is 30 and 50 wt. %. The coating has been characterized by X-ray diffraction (XRD) and scanning electron microscopy (FESEM). XRD studies reveal the presence of Ni and YSZ in the coating. The microstructural studies of the Ni-YSZ coating revealed the presence of porosity and micro cracks. The pin-ondisc studies revealed that the wear resistance of Ni-30YSZ coating is better than that of Ni-50YSZ and bare SS substrate under dry sliding conditions. Also, the coefficient of friction is low for Ni-30YSZ coating compared to the Ni-50YSZ coating. The wear rate of Ni-30YSZ coating is equivalent to that of hard chrome coating suggesting it to be a probable substitute. It was seen from the polarization studies that the HVOF deposited Ni-YSZ coatings displayed poor corrosion resistance compared to the uncoated SS due to the presence of porosity and micro-cracks a characteristic feature of HVOF coatings.