The effect of pre-sintering and deformation rate on critical current density behaviour of Bi-2223 bulk samples made by sinter forging

Abstract

A technique combining cold-isostatic-pressing (CIP) and sinter forging was applied to the fabrication of Bi-2223 bulks, and pre-sintering was conducted after (route 1) and before CIP (route 2). Both of them involve sinter forging twice and no post-annealing. The effect of pre-sintering and deformation rate on the critical current density J c is investigated. Such obtained Bi-2223 bulks had a cross-sectional area of ∼1 cm 2 and therefore the total critical current is close to meeting some technical applications. The J c results from route 1 are much higher than from route 2 although both reached highest J c at the deformation rate 80%. The main reason is that route 1 produces much larger, plate-like, better-contacted grains whereas by route 2 much smaller, round-shaped and poorly contacted grains were obtained.