Mullite ceramic was prepared using kaolinite and synthesized alumina (combustion route) by solid‐state interaction process. The influence of TiO₂ and MgO additives in phase formation, microstructural evolution, densification, and mechanical strengthening was evaluated in this work. TiO₂ and MgO were used as sintering additives. According to the stoichiometric composition of mullite (3Al₂O₃·2SiO₂), the raw materials, ie kaolinite, synthesized alumina, and different wt% of additives were wet mixed, dried, and uniaxially pressed followed by sintering at different temperature. 1600°C sintered samples from each batch exhibit enhanced properties. The 1 wt% TiO₂ addition shows bulk density up to 2.96 g/cm³ with a maximum strength of 156.3 MPa. The addition of MgO up to 1 wt% favored the growth of mullite by obtaining a density and strength matching with the batch containing 1 wt% TiO₂. These additives have shown a positive effect on mullite phase formation by reducing the temperature for complete mullitization by 100°C. Both additives promote sintering by liquid phase formation. However, the grain growth, compact microstructure, and larger elongated mullite crystals in MgO containing batch enhance its hardness properties.

中文翻译：

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高岭石与活性氧化铝制备莫来石的烧结及微观结构研究：MgO和TiO2的作用

莫来石陶瓷是使用高岭石和合成氧化铝（燃烧路线）通过固相相互作用过程制备的。在这项工作中评估了TiO ₂和MgO添加剂对相形成，微观结构演变，致密化和机械增强的影响。TiO ₂和MgO用作烧结添加剂。根据莫来石（3Al ₂ O ₃ ·2SiO ₂）的化学计量组成，将原料即高岭石，合成氧化铝和不同wt％的添加剂进行湿式混合，干燥和单轴压制，然后在不同温度下烧结。每批的1600°C烧结样品均具有增强的性能。1 wt％TiO ₂此外，堆密度高达2.96 g / cm ³，最大强度为156.3 MPa。通过获得与包含1wt％的TiO ₂的批料的密度和强度相匹配，最高达1wt％的MgO的添加有利于莫来石的生长。这些添加剂通过将完全乳化的温度降低100°C，对莫来石相的形成具有积极作用。两种添加剂均通过液相形成促进烧结。但是，含MgO的批料中的晶粒长大，致密的微观结构和更大的细长莫来石晶体增强了其硬度性能。