Preparation Of The Rare Earth Aluminate And The Investigation Of Their Sintering Behaviors

The composition of rare earth aluminate and alumina can improve the mechanical qualities of alumina ceramic, however, the report about the preparation of rare earth aluminate powder with small particle size and well distribution was a little. Moreover, the sintering mechanism of the pure rare earth aluminate powder was little. Therefore, the paper paid attention to the preparation technology for pure rare earth (Y, Eu, Ce) aluminate by sol-gel method, and studied the sintering behaviors of pure YAG and EuAlO3, which will provide guidance for the preparation of composite ceramics of rare earth aluminate and alumina with high quality.It was found that no mesophase YAP and YAM appeared during the preparation process of YAG.. The calculation of crystallite size showed that the crystallite changed little below 1100℃. At the same time, the size of the particle heated at 1000℃was 1μm by the way of laser particle size analyzer, BET and SEM, respectively. We studied the sintering behavior of YAG, and found that its'densification was not high in our sintering procedure and the average line expansion coefficient was 9.34×10-6/℃for the green compact and 10×10-6/℃for the sintered compact. The sintering activation energy for YAG was 116 and 149kJ/mol on the basis of shrinkage and relative density respectively.The pure EuAlO3 with perovskite structure could be obtained at 1000℃. It was found that the crystallite size grew quickly with the calcination temperature increasing. EuAlO3 powders prepared at different temperatures shew different agglomeration. We studied the impact of the water and isopropyl alcohol solvent on the dispersity for the powder particles respectively, and the results showed that isopropanol could improve the agglomeration of powder. The average linear expansion coefficient was 9.49×10-6/℃for EuAlO3 green compact and 10.2×10-6/℃for the sintered compact, the sintering activation energy for EuAlO3 was 126 and 161kJ/mol on the basis of shrinkage and relative density respectively.The Ce:Al=1:11 procursor calcined at 1600℃with a dwell time of 3h did not transform into pure CeAl11O18 phase completely. It was studied that the impact of proportion of Ce and Al and holding time on the preparation of CeAl11O18. We found that the mass fraction of CeAl11O18 in the composition was the most for Ce:Al=1:11 procursor heated at 1600℃with the same holding time; moreover, given a certain proportion of Ce and Al and calcining temperature, the mass fraction of CeAl11O18 increased to the maximum and then decreased with the holding time increasing.