Influence of yttria addition on the phase transformations of zirconia from zircon ore by carbothermal reduction process

Zircon ore carbothermal reduction with yttria addition has been carried out. The influences of heating temperature and yttria addition on the phase transformations of zirconia from zircon ore by carbothermal reduction have been investigated in detail. The phase transformations of zirconia from zircon ore by carbothermal reduction were monitored by X-ray diffraction. The microstructure and micro-area chemical analysis of the products were characterized by scanning electron microscopy and energy dispersive spectrometer. The chemical states of Zr 3d, Y 3d and O 1s presented in the products of zircon carbothermal reduction with 10 wt% yttria addition were investigated by X-ray photoelectron spectroscopy. The results showed that the optimized heating temperature of zircon carbothermal reduction with no addition was 1600 °C, and the main phase of the products consists of m-ZrO2, c-ZrO2, ZrC and β-SiC. Yttria addition could be introduced into zirconia lattice and caused it to form Y2O3 stabilized zirconia. Zirconia in the products would be turned into partially stabilized zirconia with yttria addition from 1 wt% to 5 wt% while it would exist in the form of fully stabilized zirconia with over 8 wt% yttria addition.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We discussed the phase transformations of zirconia which prepared from zircon ore. ► Yttria could be introduced into zirconia by zircon ore carbothermal reduction. ► YSZ, including PSZ and FSZ, could be prepared directly from natural zircon ore.