Internal Friction in MgAl₂O₄ Spinel Doped with Gallium Oxide or Alumina

Abstract

Internal friction and shear modulus in MgAl₂O₄ spinel doped with gallium oxide or alumina were measured from room temperature to 1473K. An internal friction peak was observed at 1123K and the peak area was proportional to the concentration of gallium oxide or alumina in the spinel. The activation energy of the stress induced diffusion of cation vacancies increases from 200kJ/mol to 450kJ/mol with increasing gallium oxide concentration. Effects of ionic radius and gallium and aluminium ion concentration on internal friction peaks have been discussed.