Microstructure and superconducting properties of nanocarbon-doped internal Mg diffusion-processed MgB2 wires fabricated using different boron powders. (10th March 2016)

• Record Type: Journal Article
• Authors: Xu, Da; Wang, Dongliang; Li, Chen; Yuan, Pusheng; Zhang, Xianping; Yao, Chao; Dong, Chiheng; Huang, He; Ma, Yanwei; Oguro, Hidetoshi; Awaji, Satoshi; Watanabe, Kazuo
• Is Part Of: Superconductor science & technology. Volume 29:Number 4(2016:Apr.)
• Publication Date: 2016-03-10
• Subjects: MgB2 wires -- internal Mg diffusion -- boron powders -- transport properties; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/29/4/045009
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: MgB2 /Nb/Monel monofilament wires were fabricated using four different boron powders by an internal Mg diffusion (IMD) process. The microstructure, morphology and the critical current density ( J c ) of the used boron powders and the formative MgB2 layers were analyzed and compared. It was found that the purity and particle size of the boron powder influence the superconducting properties of MgB2 wires; further that the optimized heat-treatment condition also depends on the quality of the boron powder. The highest J c was obtained in the MgB2 layer made using amorphous boron (AB) powder, although a certain amount of voids existed in the superconducting layer. The IMD-processed MgB2 layer fabricated using high-purity boron (HB) powder had also a high J c compared with the powder-in-tube (PIT) process and a few unreacted boron particles remained in it. MgB2 wire fabricated using low-purity boron (LB) powder had a high cost-performance ratio compared with the others, which is expected to allow the fabrication of large-scale and low-cost superconducting wires for practical application. However, the enhancement of the J c was not found in the MgB2 layer manufactured using the ball-milled LB (MLB) powder as expected due to the increased percentage of impurity.