| 摘要 |
PURPOSE:To improve sintering density, critical current density and processing properties, to improve and to stabilize critical temperature, to uniform crystal structure and to make composition uniform, by containing specific oxide crystal grain and Ag solid solution obtained from Ag2O3 as a starting raw material arranged at least in the vicinity of grain boundary of the crystal grain. CONSTITUTION:A given amount of powder of starting raw materials (e.g., Y2O3, BaCO3 or CuO) in order to form L-B-Cu-O oxide crystal grain (L is lanthanide element including Y; B is one or more elements selected from Ba, Sr and Ca) is ground, calcined at, e.g., about 900 deg.C for 5 hours to give powder, which is press molded. Then the pressed material is sintered in an O2 atmosphere at 900-950 deg.C for, e.g., about 10 hours and ground to give first sintered powder. The first sintered powder is blended with Ag2O3 powder in the atomic ratio to satisfy the relationship shown by the formula (x is 0.07-0.7), packed with a sheath agent, molded and processed to give a molded article, which is partially melted and sintered in an O2 atmosphere at, e.g., 950-1,050 deg.C for about 10 hours to give a second sintered material. Then the second sintered material is annealed at 50-100 deg.C/hour cooling rate. |
