Synthesis And Characterization Of Y₄Al₂O₉ Matrix Materials

There are three main compounds in AL2O3-Y2O3 system:Y3AL5O12 (YAG), YALO3 (YAP) and Y4AL2O9 (YAM). YAM has a lot of excellent performance in various applications. We report on a simple and convenient method for preparing YAM and YAM solid solution powders with a narrow particle size distribution, rod-like particle morphology, and perfect crystallization, where a chemical co-precipitation technique was combined with a molten salt process. And the main research works are as follows:(1) Rod-like YAM particles was successfully achieved via a molten salt process assisted by co-precipitation. The effects of the precipitate and pH value on the formation of YAM powders were studied. All the samples were characterized by XRD and SEM. The results show that pure phase YAM crystallites, with ca.20-400nm in particle size, could be obtained by calcinning the precursor (using ammonia as precipitate) at 1100℃ for 4h with a weight ratio (precursor to NaCl) of 1:4. The incorporation of NaCl salt can greatly promote the formation and crystallization of YAM crystallites, and control their particle morphology.(2) (Y1-xEux)4Al2O9 solid solution powders with a homogeneous particle size, rod-like particle morphology, and perfect crystallization can be easily prepared by our method. Their particle size and morphology strongly rely on x value, which finally dominates their photoluminescence (PL) properties. The prominent emission intensity of 5D0â†'7F2transition rather than 5D0â†'7F1 indicates that Eu3+ is located at low symmetry local site (without inversion center), and at x=0.10, there exist a maximum PL intensity due to the concentration quenching effect. At the same time, the effects of salt species, calcining temperature, holding time and salt quantity on PL properties and crystallization have been studied.(3) (Y1-xPrx)4Al2O9 solid solution powders also can be prepared by our method. When doped Pr3+ concentration varies, there exists a maximum PL intensity at x=0.005.Meanwhile, the effects of salt species, calcining temperature, holding time and salt quantity on PL properties and crystallization have been studied.