Oxygen Pressure Effect on the Y ₂ O ₃ —Bao—Cuo Liquidus

Concurrent DTA, TGA, and oxygen pressure measurement were used to determine liquidus temperature for compositions near YBa 2 Cu 3 O x . Liquidus temperatures were measured for oxygen partial pressures from 2 × 10 −4 to 1 bar. Liquidus temperatures decreased for lowered oxygen pressure. The ternary eutectic is 930°C for 1 bar and 854°C for 0.02 bar oxygen pressure. Incongruent melting of YB 2 Cu 3 O x occurs at 1034°C for 1 bar and 938°C for 2 × 10 −4 bar oxygen pressure. Some implications for processing are also discussed.