CALCINATION OF YBA2CU3O7-X POWDER

Although superconductors based on Bi and Tl have been shown to have superconducting transition temperatures near 125 K, neither material has proved to be sufficiently superior to YBa2Cu3O7-x ('YBCO') to detract significantly from the research interest in the rare-earth superconductors. YBa2Cu3O7-x was synthesized by mixed-oxide reaction of Y2O3, BaCO3, and CuO. The starting constituents were mixed, followed by multiple steps of calcination with interposed grinding. Heating rapidly to 900°C was shown to minimize formation of liquid during calcination while still producing a phase-pure powder. Slow heating to 900°C was shown to minimize formation of liquid during calcination while still producing a phase-pure powder. Slow heating to 900°C or fast heating to 950°C resulted in formation of a liquid phase deleterious to YBa2Cu3O7-x synthesis.