A study on the effect of Cu on the corrosion characteristics of Zr Alloys

Zr-Cu binary alloys for nuclear fuel cladding were prepared by changing Cu content from 0.1wt.% to 0.8wt.% to investigate the effect of Cu on the corrosion behavior in water at 360 .deg. C under a pressure of 2660 psi. Specimens containing 0.1∼0.5wt.%Cu had the black and uniform oxide film and the transition of corrosion rate didn't occur during 50 day corrosion test. However, 0.8wt.%Cu specimen had the white oxide film and the transition of corrosion rate occurred at the 10 day corrosion test. The weight gain in pre-transition regime generally decreased with the decreasing Cu content from 0.8 to 0.2wt.% though 0.1wt.%Cu specimen showed higher weight gain than 0.2wt.%Cu specimen. Cu content had no effect on changing the oxide structure formed in pre-transition regime but decreased electrical resistivity of the oxide due to short-circuit effect of precipitate. The fraction of precipitates in the Zr-Cu binary alloys, identified as tetragonal Zr2Cu, increased with increasing Cu content. Increase in the fraction of precipitates is though to be responsible for the increase in weight gain