Effect of iron impurity on structural development in ball-milled ZrO2–3 mol% Y2O3

Abstract

Powders Mixture of monoclinic ZrO2 and 3mol% Y2O3 were prepared by high-energy ball milling. Ball-milled products were investigated by means of X-ray diffraction, Rietveld refinement, spectrophotometry and Mössbauer spectroscopy. The tetragonal Zr1–xYxO1.982 (x=0.037) was formed within 30min of ball milling in which the crystallite size decreases up to 13nm and appears almost unchanged even after 30h of milling. Peak intensities of the monoclinic phase decrease and disappear after 10h of milling. The unit cell-volume of tetragonal phase decreases with increasing iron content incorporated from milling media. In the calcined product ball-milled for 30h the monoclinic phase takes place in the range 700–900°C and disappears at 1100°C due to the presence of Y3+ cations. It was concluded that at room temperature, the stabilization of tetragonal phase at the beginning of milling process was attributed to the substitutional Fe3+ cations, while the hematite Fe2O3 was formed at the end of ball milling.