Nano-yttria Homogeneous Precipitation Method Synthesis

In this paper, Y2O3 nano-particles were prepared by homogeneous precipitation method, technological conditions and reaction kinetics were studied. The main results are as follows:The reaction material was prepared by dissolving the raw Y2O3 in the nitric acid and urea was used as the precipitator, and the Y2O3 nano-particles were prepared by the homogeneous precipitation. The influence of the reagent concentration, molar ratio, reaction temperature and time, drying temperature and time, calcining temperature and time were studied. Results showed that homogeneous-dispersed hexagonal Y2O3 nano-particles could be prepared under the primary technological conditions.To determine the influence of technological conditions on the size of the product, we used the homogeneous design to investigate the effect of the reagent concentration, molar ratio, reaction temperature and reaction time. The result indicate that the size was mostly influenced by the reagent concentration, follow by the reaction temperature, molar ratio and the reaction time. The optimum conditions were: CY3+=0.45 mol/L ; n(urea):n(Y3+)=4. 47: 1; reaction temperature=96.91C; reaction time=3.53h. We could obtain the Y2O3 nano-particles sized 28nm under the optimum conditions.The effects of the dispersant on the size and the pattern of the particles were studied. By the observation under the condition of XRD and TEM, we found that with the immission of the dispersant, conglobation could be prevented and the size of the particles could be well controlled. Under the same molecular weight, the effect of the poly sodium acrylate was better than that of the poly acrylic acid and poly ammonium acrylate. The effect of usage of the dispersant was in great influence, which best at 15mg/mL. Furthermore, the pattern of the particle could be slightly changed with the immission of the dispersant.The kinetics in the process of precipitation and calcination were also studied. The reaction order of Y(NO3)3 during the precipitation process is 1.72, and the activeenergy is 89.71kJ/mol. TG and DSC method were used to investigate the kinetics of thermal decompostion. The active energy by the two method were 150.21kJ/mol and 162.05kJ/mol, which were close...