Dezincification of α-Brass Related to Ternary Diffusion in Cu-Zn Alloys

In the previous paper, it was reported that the dezincification of α-brass was remarkably affected by small amounts of metallic additives, and the effectiveness was discussed by considering the three types of concentration-profiles of the additives. In the case of the group of Si, Ge and Sn, an abnormal dezincification was suggested to be due to the ternary diffusion phenomena.In this paper, the experiment on the ternary diffusion was carried out at 800°C in hydrogen atmosphere by the diffusion couple method, using 8 couples of alloys of Cu-Zn-X systems (X: Ge, Sn, Ag, Fe, Co, Ni, Ga and Mn). The ternary diffusion paths were determined by measuring the concentration using EPMA.The results are summarized as follows:(1) The concentration profiles of Si, Ge and Sn were concluded to be due to the ternary diffusion caused by dezincification.(2) The profiles of Ag, Fe, Co and Ni were explained by considering the ternary diffusion.(3) The profiles of Al, Ga, Mn and Cr were interpreted as due to the oxidation of those elements.