A potential route to synthesize imporous MgB2 bulks by pretreatment of B powder at ambient pressure

作者：Pan X F; Cheng C H; Zhou J D; Zhao Y^*

来源：Superconductor Science and Technology, 2009, 22(4): 045015.

DOI：10.1088/0953-2048/22/4/045015

Imporous MgB2 bulks with a density of 1.82 g cm(-3) have been synthesized by pretreatment of B powder in an in situ solid-state reaction at ambient pressure. The results show that the MgB2 with B powder pretreatment has a significant improvement in J(c), B-irr, microstructure and intergranular coupling, but with no decrease of T-c. At 20 K and 4 T, the J(c) is enhanced by 4 times by the pretreatment of the B powder. For the B pretreated MgB2, the Birr at 20 K reaches 5 T and J(c) at 10 K and 6 T reaches 2200 A cm(-2), compared to 4.2 T and 670 A cm(-2) for the B-not-pretreated MgB2. It is argued that the small amounts of highly dispersed carbon in B powder may enhance the mobility of B particles during the reaction of B and Mg, which avoids the formation of voids in the positions of Mg particles.

• 出版日期2009-4
• 单位西南交通大学