2002/04/17 by T. Prikhna, T. A. Prikhna, W. Gawalek +33
Materials Science · Physics and Astronomy · #Boron and Carbon Nanomaterials Research #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con) #Superconductivity in MgB2 and Alloys #cond-mat.mtrl-sci #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0204362
7 pages pdf, will be presented at CIMTEC 2002
arxiv created 2002/04/17 · openalex publication_date 2002/04/17 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Bulk MgB2 - based materials with the following critical current densities (jc) in 1 T field: 570 kA/cm2 at 10 K, 350 kA/cm2 at 20 K and 40 kA/cm2 at 30 K and in 10 T field: 650 A/cm2 at 10 K have been high-pressure (HP) synthesized from Mg and B with 2 - 10 wt.% addition of Ta. In synthesis and sintering process Ta plays the role of an absorbent of impurity gases (hydrogen, nitrogen, etc.) and forms Ta2H, TaH, TaN0.1, etc., thus promotes the reduction of MgH2 in Mg-B-O-matrix phase, as well as, the impurity nitrogen and oxygen in Mg-B grains (black MgB2 single crystals distributed over the matrix). Vickers microhardness of HP-synthesized material is Hv=12.54 (+/-)0.86 GPa (at 0.496-N load) The hardness (at 60-mN load) of MgB2 single crystals located in a sample matrix is 35.6 (+/-)0.9 GPa that is higher than the hardness of sapphire (31.1 (+/-)2.0 GPa).