Cycle oxidation resistance at 800 ℃ was investigated for a nanostructured Ni Cr BSi-Ti B_2 coating sprayed by high velocity oxy-fuel. For comparison, the conventional Ni Cr BSi-Ti B_2 coating was also studied. The results indicate that the structure of oxide scale from external to internal on the nanostructured coating is complete and continuous Si O_2scale→Cr_2O_3scale, and the loose Ti O_2 particles diffuse on the oxide films. The oxidation process of the nanostructured coating is controlled by a diffusio...