Evaluation and Improvement of Methods for Detecting Intergranular Corrosion Susceptibility in Aluminum Alloys

Abstract

Abstract Present methods for determining susceptibility to intergranular corrosion in aluminum-zinc alloys were considered inadequate and attempts were made to improve or refine them. NaCl-H2O2 and electrolytic tests and modifications were studied. Results obtained with electrolytic method showed good correlation with results of NaCl-H2O2 test. The latter is believed to be more sensitive under optimum conditions, but the variables inherent in the use of H2O2 are difficult to control. Electrochemical processes by which the various methods accelerate intergranular corrosion are discussed. Modification of the present inspection method is recommended, and a quantitative method for assessing degree of severity of intergranular penetration suggested. 2.3.5