Title :
Sintering period dependence of superconducting properties of (Bi 0.7Pb0.3)1-ySr1Ca1 Cu1.8Ox system
Author :
Park, S. ; Im, H.B.
Author_Institution :
Dept. of Mater. Sci. & Eng., Korea Adv. Inst. of Sci. & Technol., Seoul, South Korea
fDate :
9/1/1989 12:00:00 AM
Abstract :
The (Bi0.7Pb0.3)1-ySr1Ca1 Cu1.8 superconductor sintered above 855°C is shown to have a microstructure consisting of superconducting platelike grains embedded in a matrix formed by semiconducting rodlike grains due to the melting of Bi2O3, whereas it has a microstructure consisting of a small number of semiconducting rodlike grains embedded in the superconducting matrix when it is sintered at 845°C. The amount of high-Tc phase increases and that of low Tc phase decreases as the sintering period increases, making it possible to fabricate superconductors with T c above 100 K by sintering at 845°C in air for 240 h. The sintering time can be shortened by sintering first below 850°C to obtain a microstructure consisting of the platelike grain matrix and resintering at higher temperature to enhance the growth of the high-Tc phase. Superconductors with a T c of 106 K have been fabricated by sintering at 845°C for 48 h followed by sintering at 855°C for 24 h
Keywords :
bismuth compounds; calcium compounds; high-temperature superconductors; lead compounds; sintering; strontium compounds; superconducting transition temperature; (Bi0.7Pb0.3)1-ySr1Ca 1Cu1.8 superconductor; 24 h; 48 h; 845 C; 855 C; X-ray diffraction; electrical resistance; high temperature superconductor; microstructure; sintering time; superconducting matrix; Bismuth; Costs; Electric resistance; Microstructure; Powders; Strontium; Superconducting films; Superconducting materials; Superconductivity; Temperature;
Journal_Title :
Magnetics, IEEE Transactions on
