Dealuminification in Cu-Al alloys is similar in mechanism to the dezincification that occurs in brass. Dealuminification was studied by means of accelerated immersion tests and anodic polarization measurements of various Cu-Al alloys, in which the content of Al was less than 12.4%. A mixed solution of 1/2mol CuSO₄+1/3mol CH₃COONa+1/3mol KCl+2/3mol CH₃COOH(pH=3.3) was used in both cases.
The results obtained were as follows:
(1) Dealuminification current that is obtained by deducting the anodic current of Cu at -0.05V from that of each alloys at -0.05V corresponds to the dealuminification rate of its alloy.
(2) Only α Cu-Al alloys have high resistivity to dealuminification.
(3) Dealuminification is increased by the appearence of phases other than α phase.