Environmentally assisted degradation of spinodal copper alloy C72900

Abstract

In this work, a spinodal Copper alloy – C72900, was tested to investigate the resistance against environmentally assisted degradation. The material was tested according to ISO 15156-3 Level V in sour H2S solution and to cathodic polarization in simulated seawater with stressed samples. The results showed no indications of hydrogen stress cracking under cathodic polarization in seawater. However, cracks up to 3 mm deep were found on the samples exposed to sour H2S environment. Energy Dispersive Spectroscopy showed severe depletion of copper close to the cracks which is associated with selective corrosion. Stress corrosion cracking was the dominating crack mechanism in the ISO 15156-3 Level V test.