Abstract:The effect of coating repair on microstructure and mechanical properties of a directionally solidified nickel base alloy IC6 was studied. The experimental results show that after coating repair treatment, the substrate/coating interface keeps well, and the combination of coating and substrate is very good , as well as very slight mutual diffusion of alloying elements between substrate and coating occurred. Although coating repair treatment make diffusion time double, only a little amount of Mo diffused into coating, and the elements Cr and Co of NiCoCrAlYHf coating only exist in a thin layer of influence region of the substrate, which has no obvious effect on the microstructure of alloy IC6. Tensile tests at room temperature and stress rupture tests under 1100℃, 90MPa of the coating-repaired sample were conducted. The results show that the coating repair has no evident effect on mechanical properties. Therefore, it may be considered that when the coating is unexpectedly destroyed, it can be repaired.

Key words: nickel aluminides；coatings; aero-engine components