Abstract: | Activities and activity coefficients of Al in solid Cu-AI alloys have been determined by meansof solid electorlyte galvanic cells Al(a_1 , in alloy), Al_2O_3 ZrO_2·Y_2O_3 Ni, NiOand Al(a_1, in alloy), Al_2O_3 Na, βAl_2O_3 Al(a_2 , in alloy), Al_2O_3 |