Effect of Mo interlayer on the diffusion behavior and mechanical property of Cr-coated Zr alloy cladding tubes

The study examined the diffusion mitigation effect and mechanical properties of a Mo interlayer, prepared by magnetron sputtering, as a Cr-Zr diffusion barrier through annealing experiments and ring compression tests. The results indicate that the existence of the Mo interlayer significantly alleviates the interdiffusion of Cr-Zr, and this effect increases with a thicker Mo interlayer. After high-temperature diffusion at 1332 ℃, the Cr/Mo-coated sample exhibited the formation of Cr, Cr (Mo) solid solution, CrZr Laves phase, Cr-Mo-Zr diffusion region, and Zr substrate structures. During ring compression tests, the Cr/Mo coating remained firmly bonded to the Zr alloy cladding tubes, even under significant ring deformation. The Mo layer has the mechanical potential to serve as a diffusion barrier for Cr-Zr. The details of Mo as a diffusion barrier are discussed.