THE DEZINCIFICATION OF ALPHA-CU-ZN

Cu-25.4 at% Zn samples were dezincified in vacuum at 450, 500, and 800 degrees C, and the changes in composition and pore configuration were followed mainly by scanning electron microscopy. Samples with (100) a nd (111) surface orientation were used in the experiments. A smaller e vaporation rate for (111) with respect to (100) surfaces could be obse rved. Three stages in the dezincification could be established: a) a h omogeneous dezincification without pore formation in the very initial stage; b) the pore formation stage with round pores which could develo p into segmented shapes, exposing preferentially (111) close packed pl anes; and c) the formation of irregular strings of pores, whose collap se leads to grooves at 800 degrees C.