Effects of He and Ni ion irradiation on the ZrO2/Cr composite coating on Zr1Nb alloy

ZrO2/Cr composite coating has been irradiated by 2.8 MeV He and 38 MeV Ni ions at 350 degrees C. Similar extents of grain-growth and partial healing of microcracks have been identified in the ZrO2 layer of both irradiated samples. The monoclinic to tetragonal transformation of ZrO2 and the formation of an amorphous (Zr,Cr)O phase at the ZrO2/Cr interface is identified in the Ni-irradiated sample. Large amounts of dislocation loops and small cavities are observed in the Cr layer while significantly less loops are found in the ZrO2 layer in both samples. The irradiation processes also cause significant growth of surface Cr oxides.