Precipitation synthesis and sintering of yttria nanopowders

Yttria nanopowders were synthesized using a chemical precipitation method. pH value at the end of the precipitation process has a significant effect on the size and morphology of the precursor and the yttria powders. Under the same calcination condition, the yttria powders made from the precursor obtained at a pH of 8 are smaller in mean particle size and narrower in size distribution than those made from the precursor obtained at a pH of 10. It was found that the optimum calcination temperature is 1000 °C, and the yttria powder obtained is fine (30 nm) and well dispersed. Using the yttria powder, transparent yttria ceramics was produced by vacuum sintering at 1700 °C for 4 h without any additives.