Effect of Rare Earth Doping on the Tensile Properties of High Temperature Oxidation Coating

The failure process was characterized by complex diffusion of elements in the bonding layer, TGO growth and growth stress inside the coating. We studied the aluminum migration phenomenon of NiCoCrAlY and NiCoCrAlYHf coatings under high temperature oxidation, TGO growth characteristics, the microstructure and composition of the bonding layer, and integrates them into the description of the surface strain under coating tension. The experimental results show that the TGO growth rate of NiCoCrAIYHf coating is lower than that of NiCoCrAIY coating, and the formed TGO is thinner. After high temperature oxidation, the cracking time of NiCoCrAIY coating is advanced, while the cracking time of rare earth doped coating is delayed. The addition of rare earth elements can effectively inhibit the generation of spinel phase, improve the fracture toughness of TGO, refine the grains in the bonding layer, and increase the grain boundary strengthening by 29.1 MPa which is consistent with the experimental value. Therefore, the yield strength of the doped coating is improved and the crack time of the coating is delayed.