Studies in the BaO_2-BaO-CuO system

摘要

The complex ternary system Ba-Cu- O has been re-visited in 0.1 MPa oxygen pressure. It is established that for such pressure, the BaO_2 = BaO + (1/2)O_2 reaction has an important role for reaching the equilibrium state. The pathway for the phase formation is then described in ternary sections BaO_2-BaO-CuO. We have specified the temperatures and the forming reactions of the 3 compounds in the system: Ba_2CuO_(3.04) decomposes by peritectic-like reaction at 1033℃ and shows a structural transition from orthorhombic to tetragonal for at 825℃, BaCuO_2 is a congruent melting compound at 1035℃ and Ba_2Cu_3O_(5.5) undergoes a peritectoiedic decomposition into BaCuO_2 and CuO at 893℃.