Effect of heat-treatment temperatures on density and porosity in MgB2 superconductor

The density, porosity, and microstructures of MgB2 samples are very important factors for transition critical current density. The effect of heat-treatment temperatures on density and porosity in MgB2 superconductors has been investigated. The open porosity increases with increasing heat-treatment temperatures, but close porosity decreases. The calculated theory densities from the lattice parameters of the measured samples are 2.6-2.63 g/cm(3). The average measured total porosity (including open and close porosity) is about 50%. (C) 2002 Elsevier Science B.V. All rights reserved.