Mechanism of intergranular corrosion of Al-Cu alloys

Abstract

The anodic behaviour of pure Al and some specially prepared Al-Cu alloys has beenstudied to check the mechanism of intergranular corrosion of aged Al-4%Cu. A clear relationship between pitting and intergranular corrosion has been found. Intergranular corrosion only occurs in the presence of certain anions, and over a narrow range of potentials. Difference in pitting potentials, rather than difference in electrode potentials, is the main factor in producing intergranular corrosion of Al-4%Cu. The conditions of heat treatment, solution composition, and potential, at which intergranular corrosion appears, have been established.