Nanostructured zirconia coating prepared by atmospheric plasma spraying

In this paper, a nanostructured zirconia coating fabricated by atmospheric plasma spraying (APS) is described. The microstructure and phase composition of the coating was characterized with SEM, TEM, XRD and Raman Spectroscopy. In addition, the bonding strength between the nanostructured Zirconia coating and stainless steel substrate has been measured. It is found that the as-sprayed zirconia coating exhibited a bimodal distribution with small grains (60–80 nm) and large grains (70–120 nm), the later is the main microstructure of the coating. The coating is composed of tetragonal zirconia; it was found that the monoclinic zirconia existing in the starting powders transformed into tetragonal phase during plasma spraying.