The Isothermal Section of the Phase Diagram of Mg-Co-Ga Ternary System

The isothermal section of the phase diagram of the Mg-Co-Ga ternary system at 200 degrees C for the full composition range was built. The formation of five ternary compounds was observed. The crystal structures of all ternary compounds: tau(1)-MgCo2Ga5 (own structure type, Pnnm space group), tau(2)-Mg3Co2Ga7 (C(2/)c space group, own structure type), tau(3)-MgCoGa2 (P2(1)/n space group, own structure type), tau(4)-Mg1-xCo2-yGax+y (x = 0.06, y = 0.64) (Cmcm space group, own structure type), tau 5Mg1-xCo2-yGax+y (x = 0.10, y = 0.16) (R-3 m space group, own structure type) were investigated by means of single crystal diffraction. In addition to ternary compounds, solid solutions based on binary phases are formed in the system. The solid solution MgCo2-xGax (x = 0-1, P63/ mmc space group, MgZn2 structure type) represent the largest area of homogeneity. The phase content of alloys was determined by SEM/EDX analysis.