Abstract A three-phase system consisting of alumina (Al2O3), magnesia (MgO) and 8 mol% yttria‐stabilized zirconia (8YSZ) was reactive flash sintered to produce MgAl2O4-8YSZ composites. We show that a critical volume fraction of the ionic conductor 8YSZ is required to promote the flash phenomenon, indicating a typical percolation behavior. The easy path for conduction could be reached with a smaller critical volume fraction when using agglomerated powders for producing the green bodies. Furthermore, microstructure and X-ray diffraction analyses demonstrate that both sintering and phase transformation largely depend on the mixing level of the precursors. Although the presence of agglomerates resulted in a decrease of the flash onset temperature, poor sintering and incomplete phase transformation were verified. This behavior is attributed to inhomogeneous heat distribution within those samples during the flash state, which could be explained by the electrical current percolation.

中文翻译：

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粉末分散度对 8 mol% 氧化钇稳定氧化锆和 MgAl2O4 复合材料反应性闪烧的影响

摘要 由氧化铝 (Al2O3)、氧化镁 (MgO) 和 8 mol% 氧化钇稳定氧化锆 (8YSZ) 组成的三相体系经反应性闪烧制备 MgAl2O4-8YSZ 复合材料。我们表明需要离子导体 8YSZ 的临界体积分数来促进闪光现象，表明典型的渗透行为。当使用团聚粉末生产生坯时，可以通过较小的临界体积分数达到简单的传导路径。此外，微观结构和 X 射线衍射分析表明，烧结和相变在很大程度上取决于前体的混合水平。尽管附聚物的存在导致闪发温度降低，但证实了不良的烧结和不完全的相变。