Zirconium is a reactive metal with great affinity to oxygen. The excellent corrosion resistance of the oxide film makes it suitable for multiple corrosion environments.
1. Corrosion rates of pure zirconium in all boiling hydrochloric acid concentrations are less than 0.025mm/a.
2. Zirconium has excellent corrosion resistance in sulfuric acid less than 70%. In addition, as stainless steel and nickel alloys cannot be used in the range of sulfuric acid below high temperature, 20% sulfuric acid and 40-60% boiling temperature, zirconium plays an irreplaceable role in sulfuric acid environment.
Third, under 200 ℃, no greater than 90% nitric acid, zirconium has good corrosion resistance. But attention should be paid to the sensitivity of zirconium to stress corrosion cracking in nitric acid.
Zirconium is resistant to corrosion at all concentrations even in boiling caustic solutions. Its corrosion resistance exceeds tantalum, niobium and titanium.
Zirconium alloys are mainly used as cladding materials and other internal components of nuclear reactor fuel elements. The main research results and problems about corrosion of zirconium alloy are reviewed. The existing theories and challenges are summarized. In the 1980s, great progress was made in the study of chemical composition, microstructure and the effect of irradiation on corrosion resistance of zirconium alloys. In recent years, the research work mainly focuses on exploring the corrosion mechanism, selecting the best alloy composition and controlling the microstructure, so as to meet the higher requirements for zirconium alloy after increasing the fuel consumption and reducing the nuclear power cost.
