PREPARATION AND CHARACTERIZATION OF Er:Gd2O3 POWDERS

The co-precipitation method and sol-gel combustion method were used to prepare Er:Gd2O3 powders. The process of heat disassembly, phase composition, morphology and purity of the powders were investigated by TG-DTA, XRD, SEM and FTIR, respectively. The powders having cubic phase were obtained by sol-gel combustion method when citric acid and EDTA were used as combination fuel. They are fluffy, porous and agglomerated and its grains are irregular in morphology. Besides oxalate being generated, Gd2O2CO3 is generated in the process of heat treatment by oxalic acid co-precipitation method. The decomposition temperatures of oxalate and Gd2O2CO3 are about 401 degrees C and 642 degrees C. The grains prepared by acid co-precipitation method are flaky, having uniform size and clear crystal boundary. After 900 degrees C heat treatment, the average length of the flaky grains is about 1 mu m, and the average thickness is about 20nm. The powders prepared by these two methods are a cubic phase, and easily absorb CO2 to form CO32- on the surface of the grains.