The behaviour of air-plasma-sprayed zirconia in high temperature reactor helium

Thermally sprayed coatings are being considered for use in areas of helium- cooled high temperature reactors (HTRs) which primarily have to resist wear. In addition to wear, these coatings have to be resistant to corrosion by HTR helium. The purpose of this paper is to present the results of a study into the response of an air-plasma-sprayed $\text{(Ni-Cr-Al-Y)}\text{(ZrO}{}_2\text{-Y}{}_2\text{O}{}_3\text{)}$ duplex coating to HTR conditions. The evaluation of this coating deals with the areas of thermal shock, non- self-welding, sliding wear, exposure, structural stability in HTR helium and strain tolerance.