Ammonium sulfate and PEG composite surfactant to promote dispersibility of precursors and Y2O3 powders for transparent ceramics

Well-dispersed Y2O3 powders were synthesized by a precipitation method from yttrium nitrate solution using (NH4)2SO4 and PEG4000 as the composite surfactant, and the dispersion mechanism of the composite surfactant was investigated in detail. Furthermore, the grain size, densification, mechanical and optical quality of as-prepared ceramics were also discussed. The dispersion state of both precursors and Y2O3 powders could be remarkably effected by the mass ratio of (NH4)2SO4 and PEG4000 during the liquid phase reaction process. When the function of electrostatic repulsion and the steric hindrance were combined properly, the aggregation state of powders could be effectively inhibited. With the addition of the mass ratio of 3:2 ((NH4)2SO4 to PEG4000), fine powders (130 nm) with high dispersion state were obtained. Meanwhile the Y2O3 ceramics with an average grain size of 3.65 µm were fabricated by sintering at 1750 °C for 8 h.