TETRAGONAL-REVERSIBLE-ARROW-MONOCLINIC PH ASE-TRANSITION TEMPERATURE OF RARE-EARTH-DOPED ZIRCONIA PREPARED BY ARC MELTING

The tetragonal (t) reversible monoclinic (m) phase transition temperat ure of compositionally homogeneous arc-melted ZrO2-RO1.5 solid solutio ns (R = Nd, Sm, Er, Yb and Sc) was investigated by TMA (thermomechanic al analysis; dilatometer) and high-temperature X-ray diffraction. The t reversible m transition was observed in ZrO2-x mol% RO1.5 (x = 0, 2 and 4 for R = Nd, Sm, Er and Yb, and x = 2, 4, 6 for R = Sc), but not in specimens with higher dopant content. The equilibrium temperature T 0t-m between t-and m-phases decreased linearly with an increase of dop ant content x, the degree of which \dT0/dx\ was larger for dopants wit h larger ionic radii.