Abstract Lightweight Al2O3–MgAl2O4 refractories can be achieved by producing a density gradient structure which guarantees good slag resistance and low thermal conductivity. To further improve the mechanical properties of this material, in this study, in situ platelike structure was developed by adding different amounts of SrCO3 in the matrix. The phase composition, microstructure, physical and mechanical properties of the obtained lightweight refractories were characterized and evaluated. The results showed that besides corundum and spinel, platelike MgSrAl10O17 phase was also formed during reactive sintering. The well-developed MgSrAl10O17 phase possessing an interlocking structure formed grain-grain bridging with MgAl2O4, which significantly improved the mechanical performance of lightweight Al2O3–MgAl2O4 refractories. Although no obvious changes occurred in apparent porosity and bulk density of the specimen, the compressive strength and refractoriness under load were significantly improved after SrCO3 addition, which increased from ~50 MPa to ~80 MPa and 1589 °C–1656 °C, respectively. To better understand the relationship between microstructure evolution and improvement in performance, the formation mechanism of the MgSrAl10O17 phase and its reinforcement mechanism in the material were described in detail.

中文翻译：

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MgSrAl10O17的形成机理及其对轻质Al2O3-MgAl2O4耐火材料力学性能的影响

摘要 轻质Al2O3-MgAl2O4耐火材料可以通过生产密度梯度结构来实现，该结构保证了良好的抗渣性和低热导率。为了进一步提高这种材料的机械性能，在本研究中，通过在基体中添加不同量的 SrCO3 来开发原位板状结构。对所得轻质耐火材料的相组成、微观结构、物理力学性能进行表征和评价。结果表明，反应烧结过程中除了刚玉和尖晶石外，还形成了片状MgSrAl10O17相。发育良好的具有互锁结构的 MgSrAl10O17 相与 MgAl2O4 形成晶粒-晶粒桥接，显着提高了轻质 Al2O3-MgAl2O4 耐火材料的力学性能。尽管试样的表观孔隙率和堆积密度没有发生明显变化，但加入 SrCO3 后，试样的抗压强度和耐火度显着提高，分别从~50 MPa 增加到~80 MPa 和 1589 °C-1656 °C。为了更好地理解微观结构演化与性能改进之间的关系，详细描述了材料中 MgSrAl10O17 相的形成机制及其增强机制。