Stress Corrosion of Eta-Phase, Hot-Dip-Zinc Alloy in Potable-Hot Water

Eta-phase-zinc alloy is susceptible to stress corrosion failure when exposed to the circulating, potable hot water used in this study. Time to failure decreased from about 2850 to 150 hours as the applied tensile stress was increased from 2040 to 6720 psi. Metallographic examination revealed that the cracks propagated primarily intergranularly. Stress corrosion could be mitigated by cathodic protection. High purity (99.9%) zinc did not appear to be susceptible to stress corrosion in this environment.