The Prevention Potential of Pitting Corrosion Growth of Aluminum in Fresh Water

Abstract

A characteristic potential for prevention of pitting corrosion growth of Al-1100 in fresh water has been estimated by measuring the time dependence of current at various potentials in artificial water and tapwater, the weight loss of aluminum and the amount of Al³⁺ ion dissolved. The artificial water contained 12.0ppm of Na₂SO₄ and 8.8ppm of NaCl. The weight loss of Al-1100 after controlled-potential electrolysis was found to be the least at -0.45V (SCE) in artificial water and at -0.35V in tapwater. A scanning electron microscopic observation revealed that, although a few corrosion pits were formed on the surface of aluminum, they did not grow at the potential estimated above. These potentials, therefore, may be regarded as the prevention potential of pitting corrosion of growth of aluminum in artificial water and tapwater.