DENSIFICATION OF BI1.8(PB)0.35SR1.9CA2.1CU3OX AND TEXTURE DEVELOPMENT THROUGH SINTER-FORGING

A technique known as sinter-forging has been used to achieve dense Bi1.8(Pb)0.3sSr1.9Ca2.1Cu3Ox high-T(c) superconducting material with oriented grains. The relationship between the final microstructure and processing conditions was elucidated. Material density and texture increases with the hot-forging pressure and temperature. Grains are elongated with the c-axis oriented approximately parallel to the direction of applied stress. The degree of grain orientation has been quantified using X-ray diffraction and is reported in terms of Lotgering's orientation factors. A maximum orientation factor of 38% was found for processing at 830-degrees-C and 4 MPa in air. The influence of the sintering temperature and atmosphere on the electrical properties has been investigated. After processing at 810-degrees-C and 4 MPa, the sinter-forged materials exhibit superconductivity, according to resistivity measurements, with a T(c) (R=0) of 104 K. The critical current density at 77 K increases with increasing bulk density.