O-Ps-related modes for study of free-volume entities in nanostructured MgAl2O4 ceramics

Abstract

The o-Ps-related modes are used for study of free-volume entities in nanostructured spinel MgAl2O4 ceramics after drying and water-immersion treatment. It is established that that water-sorption processes in magnesium aluminate ceramics leads to corresponding increase in positron trapping rates of extended defects located as addition phases near grain boundaries. These phase extractions and free-volume entities in ceramic structure serve as specific trapping centers for positrons penetrating ceramics. It is demonstrated that Tao-Eldrup model can be adequately used for the calculation free volume (or nanopores size) in MgAl2O4 ceramics using o-Ps lifetimes of the third and the fourth components.