Synthesis and formation mechanism of nanocrystalline ZrB2– Al2O3 composite powders via an amorphous precursor
Synthesis and formation mechanism of nanocrystalline ZrB2– Al2O3 composite powders via an amorphous precursor
复制标题
非晶态前驱体纳米晶ZrB2-Al2O3复合粉末的合成及形成机理
DOI：
10.1007/s12598-020-01428-y
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发表时间：
2021
期刊：
影响因子：
8.8
通讯作者：
Qiang Zhen
中科院分区：
文献类型：
--
作者：
Shao-Lei Song;Yong-Li Fan;Rong Li;Yue-Hua Lin;Qiang Zhen
以一种新型的ZrB2前驱体和Al粉为原料，在1100℃下合成了ZrB2-Al_2O_3复合粉末。最终得到的复合粉末由亚微米级的Al_2O_3和纳米级的ZrB_2(50~100 nm)颗粒组成，在微观尺度上混合均匀。结合热力学计算和实验结果，提出了ZrB_2-Al_2O_3复合粉末的形成机理为：前驱体首先分解为ZrO_2和无定形B_2O_3。在铝热还原过程中，ZrO_2和B_2O_3生成了Zr和B原子，生成了Al_2O_3和Al，生成了La_2O_3和Al_2O_3。然后，Al_3Zr和B_2O_3通过液-固反应得到了ZrB_2、Al_2O_3和Al，这是转化过程中的限制步骤。当Al_3Zr耗尽时，Al、ZrO_2和B之间的反应成为生成ZrB_2和Al_2O_3的主要反应。
ZrB2–Al2O3composite powders were synthesized at 1100 °C using a novel ZrB2precursor and Al powders as raw materials. The final ZrB2–Al2O3composite powders consisted of submicron Al2O3and nanosize ZrB2(50–100 nm) particles, which were homogeneously mixed in microscale. Combined with thermodynamic calculation and experiment results, the formation mechanism of ZrB2–Al2O3composite powders was proposed as follows: ZrB2precursor first decomposed into ZrO2and amorphous B2O3. Aluminothermic reduction of ZrO2and B2O3generated Zr and B atoms and the coproducts Al2O3, and then, a series of reactions between Zr atoms, B atoms and Al took place to form ZrB2and Al3Zr. Then, ZrB2, Al2O3and 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, ZrO2and B became the main reaction to obtain ZrB2and Al2O3.