Corrosion of Zr-Sn-X (X: Fe, Ni or Cr) Ternary Alloy in High Pressure Steam at High Temperature
Masahisa Inagaki, Masakiyo Izumiya, Hideo Maki
Effects of the addition of Fe, Ni, or Cr to Zr-Sn binary alloy and material processings on corrosion resistance in high temperature, high pressure steam were investigated in order to make clear the correlation between corrosion resistance of Zr alloy and electrical characteristics of oxide film. The increase of Fe or Ni content in Zr-Sn alloy improved the corrosion resistance, whereas with the increase of Cr content, improvement of corrosion resistance was not remarkable. Corrosion resistance was also improved by the heat treatment which depresses the precipitation and the. growth of intermetallic compounds containing Fe, Ni, or Cr. From the facts that the increase of Fe or Ni content and the heat treatment to improve the corrosion resistance decrease the electrical conductivity of the oxide film formed on Zr alloys, electrical conductivity of oxide film is considered to be the rate-determining factor in oxidation of Zr alloys in high temperature, high pressure steam.