Observations of Corrosion Product Formation and Stress Corrosion Cracking on Brass Samples Exposed to Ammonia Environments

The corrosion product formation and the stress corrosion cracking of brass in different ammonia environments have been observed and characterized. Optical and scanning electron microscopy techniques were used to analyze the corrosion phenomena on the systems. The testing methodology was designed to investigate the variables affecting stress corrosion cracking behaviour, these parameters were: stamp geometry, immersion time, Cl- concentration, pH, copper ions concentration, exposure to vapour/liquid. From this investigation, stress corrosion cracking of brass was shown to occur most severely in ammonia vapour. The increase of the amount of ammonia and copper ions in the form of copper sulphate was found to increase the corrosion of the brass samples.