Corrosion of Zr-1Nb and Zr-2.5Nb in 0.1 M LiOH at 343°C

The corrosion behavior of Zr-2.5%Nb pressure tube material and Zr-1%Nb aged at 560 °C for 4 months has been studied in 0.1 M lithium hydroxide solution at 343 °C. The results were compared with those obtained in steam at 400 °C. In the latter, aged alloys showed better behavior than the non-aged materials, whereas the ageing did neither delay the transition nor reduce the weight gains in 0.1 M lithium hydroxide. Second phase particles of Zr-Nb-Fe and Zr-Fe present in aged Zr-1Nb (α+β) and aged Zr–1Nb α’ seem to increase hydrogen uptake during post-transition in 0.1 M lithium hydroxide. Regarding the hydrogen absorption in the post-transition period, Zr-1Nb alloys show better performance than Zircaloy-4.