以氧氯化锆(ZrOCl2∙8H2O)、硼酸(H3BO3)、水合氯化镧(LaCl3∙7H2O)、正规酸乙酯(TESO)和葡萄糖(C6H12O6)为主要原料,以聚乙二醇(PEG)为分散剂,采用溶胶凝胶法和碳热/硼热还原工艺制备ZrB2-SiC-LaB6超细复相粉体。利用X射线衍射、扫描电镜、红外光谱和差示扫描量热分析等对ZrB2-SiC-LaB6粉体进行表征,研究烧结温度、原料配比对复相粉体合成过程的影响。结果表明,当原料中n(Zr)∶n(B)∶n(Si)∶ n(La)∶n(C)=1∶3∶0.7∶0.16∶8时,在氩气气氛中1 500 ℃保温2 h,可合成高纯ZrB2-SiC-LaB6超细复相粉体。颗粒平均粒径为300 nm,其中ZrB2相为六方晶系,SiC相和LaB6相为立方晶系,三元微晶平均尺寸为33.2 nm。
ZrB2-SiC-LaB6 ultrafine multiphase powders were prepared by the way of sol-gel method and carbothermal/borothermal reduction process, using zirconium oxychloride (ZrOCl2·8H2O), boric acid (H3BO3), hydrated lanthanum chloride (LaCl3·7H2O), ethyl orthoate (TESO), and glucose (C6H12O6) as the main raw materials, polyethylene glycol (PEG) as the dispersant. The effects of different temperatures and raw material ratios on the synthesis process of composite powders were studied and characterized by X-ray diffraction, SEM, infrared spectroscopy, and differential thermal scanning. The results show that when n(Zr)∶n(B)∶n(Si)∶n(La)∶n(C) =1∶3∶0.7∶0.16∶8 in the raw material, ZrB2-SiC-LaB6 superfine multiphase powders can be synthesized by holding at 1 500 ℃ for 2 h under argon atmosphere. The average particle size of multiphase powder is 300 nm, in which ZrB2 phase is hexagonal crystal system, SiC and LaB6 phase are cubic system, and the average size of ternary crystallite is 33.2 nm.
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