Phase relations in ZrO2-La2Zr2O7-Y2Zr2O7system

The phase relations in the system ZrO2-La2Zr2O2Y2Zr2O7 have been investigated using X-ray diffraction. Mixed oxide phase assemblages were prepared by hydrolysing zirconium hutoxide with solutions of Y and La nitrates, followed by drying, calcining, and sintering. The cubic zirconia phase can accept into solid solution the larger, non-cubic stabilising lanthanum ion in the presence of a suitable proportion of the cubic stabilising oxide of yttrium. As the amount of the larger rare earth element ion is increased formation of pyrochlore and tetragonal type compounds is favoured. BCT/344