Abstract
The phase equilibria around YBa 2Cu 3O 7− x (123) and YBa 2Cu 4O 8 (124) phases at low oxygen partial pressure (≦1 atm) were investigated by X-ray diffraction and thermal analysis. The coexistence of 123 and 124 phase was confirmed under 1 atm oxygen pressure. By using the high temperature X-ray diffraction method, the univariant reaction YBa 2Cu 3O 7− x +Cu 2O⇆Y 2BaCu 2 O 2+O 2 was identified. The oxygen partial pressure dependence of several univariant reactions has been investigated and the existence of two invariant reactions of L+O 2⇆YBa 2Cu 3O 7− x + BaCuO 2+CuO+Cu 2O and L+Y 2BaCuO 5+O 2⇆YBa 2Cu 3O 7− x +CuO+Cu 2O was deduced to occur at 1103 K under 0.0032 atm O 2 and at 1143 K under 0.0085 atm O 2, respectively.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
