Sintering additives for zirconia ceramics

Measurements have been made of the effectiveness of MgO as a sintering aid for the densification of stabilized zirconia ceramics. Using fast firing and conventional firing it has been found that small additions of MgO in solid solution (typically less than 1 m/0) are effective in increasing the fired density of CaO or Y2O3 stabilized materials, final porosity values of < 1% being attainable. Surface area measurements on partially fired materials suggest that MgO is effective in reducing the extent of particle coarsening during sintering heat treatments; it is argued that the role of MgO in promoting the sintering of stabilized ZrO2 lies in an ability to reduce the surface diffusion coefficient for the material. (author)