AI203/TiA1 composites were fabricated by in-situ reaction synthesis using Ti, A1, TiO2 and Sm203 as starting materials. Effect of the doping Sm203 on the microstructures and properties of the A1203/TiA1 composites was analyzed by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and universal properties tests. The results show that the phases of the Sm203-doped composites are mainly composed of ）,-TiA1/a2-Ti3A1 matrix and reinforcing phases of A1203 and SmA1. The microstructures of A1203/TiAI composites are significantly refined with doping Sm203. Doping Sm203 has a positive effect on improving the mechanical properties of AlaO3/TiA1 composites. When the Sm content is 5% （mass fraction）, the flexural strength and fracture toughness reach the maximum values of 658.9 MPa and 10.13 MPa＇m~/2, respectively.
High purity ZrSiO4 powders were prepared using zirconium oxychloride and tetraethoxysilane as raw materials by the microwave-hydrothermal method at 160-200 ℃ for 30 min, in which NaF was added as mineralizer to promote the crystallization of zircon. The phase composition and microstructure of synthesized ZrSiO4 powders were investigated in detail. The results show that: the microwave-hydrothermal method greatly reduces the synthesis temperature of ZrSiO4 to 160 ℃, 30 min. The synthesized ZrSiO4 powders have small particle size and high stability up to 950 ℃. The synthesis mechanism of ZrSiO4 by microwave hydrothermal s process was also discussed.
Liu Dawei, Wang Feng, Zhu Jianfeng, Li Dong Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science and Technology, Xi’an 710021, China
