Stress Corrosion Cracking of Zirconium in Boiling Nitric Acid Solution at Potentiostatic Condition

摘要

Zirconium has been utilized in reprocessing plant because of its superior corrosion resistance. But stress corrosion cracking (SCC) susceptibility had been reported in some conditions. In order to clarify the SCC occurrence criteria of Zr in boiling nitric acid solution, constant load tests at potentiostatic condition were conducted. From the results, SCC of Zr in nitric acid solution occurred only at transpassive region, and it is attributes to tarnish rupture model. From the observation of intermediate samples, many cracks initiate under oxide film and then the maximum crack has grown to rupture. When the reprocessing plant operates in the potential of passivity region, SCC of Zr will not occur.