ZrB2–Al2O3 composite powders were synthesized at 1100 °C 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. Aluminothermic reduction of ZrO2 and B2O3 generated 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 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.

中文翻译：

---

非晶前驱体纳米晶ZrB2-Al2O3复合粉末的合成及形成机理

以新型 ZrB2 前驱体和铝粉为原料，在 1100 ℃下合成了 ZrB2-Al2O3 复合粉体。最终的 ZrB2-Al2O3 复合粉末由亚微米 Al2O3 和纳米级 ZrB2（50-100 nm）颗粒组成，它们在微米级均匀混合。结合热力学计算和实验结果，提出ZrB2-Al2O3复合粉体的形成机理如下：ZrB2前驱体首先分解为ZrO2和无定形B2O3。ZrO2和B2O3的铝热还原生成Zr和B原子以及副产物Al2O3，然后Zr原子、B原子和Al之间发生一系列反应生成ZrB2和Al3Zr。然后，通过 Al3Zr 和 B2O3 之间的液固反应获得 ZrB2、Al2O3 和 Al，这是转化过程中的限制步骤。当 Al3Zr 耗尽时，