High temperature oxidation resistance of plasma sprayed NiCrAl+(ZrO{sub}2+Y{sub}2O{sub}3) gradated coating on stainless steel surface

摘要

The plasma sprayed gradated coating with the bottom layer of NiCrAl and the top layer of (ZrO{sub}2+Y{sub}2O{sub}3) was prepared by the plasma spraying technique. The phase structure and morphology of the gradated coating were analyzed by means of X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The high temperature oxidation resistance of the plasma sprayed samples at 800°C was investigated. The oxidation kinetics curve was obtained. The results show that the thickness of gradated coating is about 410μm. The plasma sprayed gradated coating on stainless steel surface can improve the high temperature oxidation resistance of stainless steel. The oxidation rate of stainless steel is less than that of plasma sprayed gradated coating. The oxidation film of plasma sprayed sample is very dense and is not easily exfoliated. The dense oxidation film prevents the stainless steel from more oxidation.