Microstructure evolution and interdiffusion behaviour of Cr/Mo coated Zr-4 alloys at 1330 °C-1500 °C

The Cr and Cr/Mo coated Zr-4 alloys were deposited using magnetron sputtering deposition, and their microstructure evolution and interdiffusion behaviour were investigated. High-temperature diffusion tests revealed that the Cr-Zr eutectic reaction caused the performance of the Cr coating to drastically decline at 1330 °C, while the Cr/Mo coating was effective in preventing Cr-Zr interdiffusion even at 1400 ℃. Notably, the potential impact of the Mo-Zr diffusion layer formation on the service performance of the coatings should be considered. However, the Mo interlayer lost its blocking effect at 1500 ℃, led to severe deformation of the Zr-4 alloy. In addition, the diffusion mechanism was discussed.