Mechanical alloying process of the zirconia–8 mol % yttria ceramic powder

The phase transformation process of zirconia–8 mol % yttria powder mixtures during a high energy ball milling process has been studied by means of x-ray diffraction analysis. It has been found that the m-ZrO2 (monoclinic zirconia) transforms first to m-ZrO2 solid solution and then to t-ZrO2 (tetragonal zirconia) solid solution. Finally, a single cubic zirconia solid solution phase forms after prolonged milling. The structural transformation is discussed and explained in terms of the phase relations in zirconia-yttria ceramics and the nonequilibrium nature of the mechanical alloying.