Phase transformation and superconducting properties of Mg[B.sub.2] using ball-milled low purity boron

The superconducting properties of Mg[B.sub.2] made from low-grade 96% B powder with a strong crystalline phase as a function pf ball-milling time are examined. The pinning force strength of the samples using ball-milled 96% B is larger than that of the reference sample using commercial 96% B powder and these have accompanied enhanced irreversibility and upper critical fields.