Effect of the calcium alumino-titanate particle size on the microstructure and properties of bauxite-SiC composite refractories
Effect of the calcium alumino-titanate particle size on the microstructure and properties of bauxite-SiC composite refractories
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DOI：
10.1016/j.ceramint.2018.01.059
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发表时间：
2018
影响因子：
5.2
通讯作者：
C. Jianwei;Huizhong Zhao;Han Zhang;Zhen-Gang Li;Jiaqin Zhang
中科院分区：
文献类型：
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作者：
C. Jianwei;Huizhong Zhao;Han Zhang;Zhen-Gang Li;Jiaqin Zhang
水泥回转窑耐火材料过渡区的耐碱性能和热机械性能是影响其使用寿命的关键因素。以铝土矿、SiC、CAT、广西白粘土、α-氧化铝和金属硅粉为原料，以Al(H2PO4)3为粘结剂，制备了含铝土矿钛酸钙铝复合材料（CAT）。研究了CAT粒度对烧结过程中含CAT铝土矿-碳化硅复合材料相组成、显微组织、热力学性能和耐碱性能的影响。结果表明，CAT粒度对复合材料的显微组织和烧结致密性有较大影响。随着颗粒尺寸的减小，颗粒-颗粒和颗粒-基体界面结合逐渐恶化。添加CAT颗粒后，试样的强度、承载耐火度和残余断裂强度均高于添加CAT粉末的试样。细碎CAT粉末试样的热膨胀系数低于集料CAT试样。碱侵蚀试验证实，含CAT骨料的铝土矿-碳化硅复合耐火材料的抗碱性能优于含CAT细粉的铝土矿-碳化硅复合耐火材料。根据碱作用机理，1)K蒸气通过开放且连通的孔隙和裂纹渗透试样，2)K蒸气与钙长石和刚玉反应生成钾硅石，并形成液相和新的裂纹。
Alkali resistance and thermo-mechanical properties of the transition zone of cement rotary kilns refractories are the key factors affecting their service life. Calcium alumino-titanate (CAT) containing bauxite-SiC composites were prepared using bauxite, SiC, CAT, Guang Xi white clay, α-alumina, and metallic silicon powder as starting materials and Al(H2PO4)3as the binder. The effects of the CAT particle size on the phase composition, microstructure, thermo-mechanical properties, and alkali resistance of the CAT-containing bauxite-SiC composites during firing were investigated. The results reveal that the CAT particle size strongly affects the composites’ microstructure and sintering densification. With decreasing particle size, the particle-particle and particle-matrix interfacial bonding deteriorates gradually. When CAT particles are added, the specimens show higher strength, refractoriness under load, and residual rupture strength than the specimens with fine CAT powders. Specimens with fine CAT powders show lower coefficient of thermal expansion compared to the specimens with CAT aggregates. The alkali attack test confirms that the bauxite-SiC composite refractories with CAT aggregates show better alkali resistance than those with CAT fine powder. According to the alkali mechanism, 1) K vapors penetrate the specimen through the open and connected pores and cracks, 2) K vapors react with anorthite and corundum to form kalsilite accompanied by the formation of a liquid phase and new cracks.