Properties of sol–gel derived Al2O3–15 wt.% ZrO2 (3 mol% Y2O3) nanopowders using two different precursors

An alumina–15 wt.% zirconia (3 mol% yttria) nanopowder was synthesized by sol–gel method using salt and alkoxide as precursors. Al(NO3)3·9H2O, ZrOCl2·8H2O and Y(NO3)3·6H2O were used as salt precursors and Al(OC4H9)3 and Zr(OC4H9)4 were used as alkoxide precursors. The dried gels of two precursors were heat treated in the range of 450–1350 °C. The powders produced by alkoxide precursors calcined at 750 °C were in the range of 15–75 nm, while those prepared by salt precursors had the size in the range of 30–90 nm. The former powders had a higher surface area and smaller mean pore diameter compared with the later powder, i.e. 152 m2/g and 5.63 nm comparing with 121 m2/g and 9.79 nm, respectively. Therefore phase transformation in the former occurred in lower temperatures.