Abstract: Because ceramic gradient coating with excellent performance will be affected by air oxidation effects in air atmosphere plasma spray coating preparation,Ni-Cr-B-Si/Al₂O₃ gradient coating is prepared in controlled atmosphere(argon) plasma spraying.The atmospheric conditions of making Ni-Cr-B-Si/Al₂O₃ gradient coatings are compared,and the effects of argon atmosphere on the microstructure and bonding strength of sprayed gradient coating are analyzed.The results show that the inside organization of gradient coating in argon atmospheres and in air has no obvious interface and achieves continuous change of microstructure,but the gradient coating organization in argon is more dense,lower oxidative and has higher bonding strength than that in air.