The effects of attrition and ball milling on the properties of magnesium diboride

Abstract

Commercially produced magnesium diboride powder was modified by attrition milling and ball milling in propan-2-ol for various durations. These powders were characterized by particle size distribution measurements using laser diffraction, impurity analysis by X-ray diffraction, energy dispersive spectroscopy and X-ray photoelectron spectroscopy, and by scanning electron microscopy, and were then used to produce magnesium diboride samples by pressureless heat-treatment at peak temperatures up to 1100 o C. X-ray diffraction, scanning electron microscopy, Vickers hardness measurements, and density measurements using the Archimedes method were carried out to characterize the properties of the samples, as well as determination of their superconducting properties using the magnetization method. Magnesium diboride produced from powder milled under some conditions had higher J c,mag than those produced from as-purchased powder, but the relationship between milling duration or energy and superconducting performance is a complex one, affected by both particle size and impurity content of the starting powder.

Optimization of vortex pinning at grain boundaries onex-situMgB2bulks synthesized by spark plasma sintering

“…On the other hand, the J c decrease for finer grains originated from the fact that the impurities diffusing at the grain surfaces degraded the connectivity between the grains. The similar J c and B T characteristics optimized for the grain size were also found in several reports [11,27,28]. In contrast, the monotonic increase of J c with decreasing grain size was observed for MgB 2 being free from the mechanical milling process [26,29].…”

Ultrashort Pulsed Laser Ablation of Magnesium Diboride: Plasma Characterization and Thin Films Deposition

“…On the other hand, XRD analysis of the same target shows the presence of both crystalline MgB 2 and MgB 4 , with the first as the main component and the second presenting only in a small amount. These results are not completely unexpected, since it is known that commercial powders are often nonstoichiometric [38], but, of course, they add further uncertainty to the interpretation of the results obtained in the thin films deposition.…”