| In order to develop the new zirconium alloys for cladding materials, the effects of Nb addition and the final heat treatment on the microstructure and corrosion characteristics of Zr-xNb(x = 0.2, 1.0 wt.%) alloys were investigated. The 1.0Nb alloy showed higher corrosion resistance than 0.2Nb alloy at 360℃, 70 ppm LiOH solution. The microstructure of oxide films that having equal oxide thickness has been characterized by TEM. The oxide of 1.0Nb alloy was mainly composed of columnar grains but the oxide of 0.2Nb alloys was mainly composed of equiaxed grains. From the XRD analysis of equal oxide thickness, the oxide of 1.0Nb alloy has higher tetra-ZrO₂ volume fraction than 0.2Nb alloys. Also when hydrogen pick-up content and fraction were measured with the corroded specimens of 0.2, 1.0Nb alloy at pre and post transition region, the hydrogen pick-up content and fraction were lower in 1.0Nb than 0.2Nb alloy. From the final heat treatment effect, the 1.0Nb alloy was affected annealing temperature but the 0.2Nb alloy was not. |
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