【摘 要】
：
ZrB2-Al2O3 composite powders were synthesized at 1100℃ using a novel ZrB2 precursor and Al powders as raw materials.The final ZrB2-Al2O3 composite powders cons
【机 构】
：
School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Nano-Science a
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ZrB2-Al2O3 composite powders were synthesized at 1100℃ using a novel ZrB2 precursor and Al powders as raw materials.The final ZrB2-Al2O3 composite powders consisted of submicron Al2O3 and nanosize ZrB2(50-100 nm)particles,which were homogeneously mixed in microscale.Combined with thermodynamic calculation and experiment results,the formation mechanism of ZrB2-Al2O3 composite powders was proposed as follows:ZrB2 precursor first decomposed into ZrO2 and amorphous B2O3.Alu-minothermic reduction of ZrO2 and B2O3 generated Zr and B atoms and the coproducts Al2O3,and then,a series of reac-tions between Zr atoms,B atoms and Al took place to form ZrB2 and Al3Zr.Then,ZrB2,Al2O3 and Al were obtained through a liquid-solid reaction between Al3Zr and B2O3,which is the limiting step in the conversion process.When the Al3Zr was exhausted,the reaction between Al,ZrO2 and B became the main reaction to obtain ZrB2 and Al2O3.
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