Stabilization of ZrO2 Concentrate by Rare Earth Elements (La, Nd, Pr, Ce)

Resumo

The effect of annealing and sintering temperature on phase transformation of ZrO₂ is studied in relation to REE concentrate content using differential thermal analysis, Raman spectroscopy and x-ray diffraction. It is shown that introduction of REE concentrate in an amount of more than 15 wt.% stabilizes ZrO₂ tetragonal phase solely at below 1200 °C. A further increase in temperature leads to destabilization of the tetragonal phase with formation of the monoclinic and cubic phases of the Ln₂Zr₂O₇ type isostructural compounds (n = La, Nd, ...) with a pyrochlore structure.