【作者】 李有奇；

【导师】 李亚伟；

【作者基本信息】 武汉科技大学 ， 材料学， 2004， 硕士

【摘要】 二铝酸钙（CA₂）和六铝酸钙（CA₆）是CaO-Al₂O₃二元体系中两类重要化合物。二铝酸钙材料具有很低的热膨胀系数，在和其他高熔点、高膨胀系数材料（比如MgO、CaZrO₃等）复合时可以很好的降低复相材料的热膨胀系数低；六铝酸钙材料在高温还原气氛下有很好的稳定性、在碱性环境中有足够的抗侵蚀能力以及其在含氧化铁渣中具有低溶解性，被认为是一种有前途的高温材料，同时六铝酸钙具有六方片状晶体结构以及与刚玉相有很好的化学相容性和相近的热膨胀系数的特点，人们将之引入氧化铝陶瓷基质中来增韧氧化铝陶瓷。 本论文拟采用反应烧结法合成了CA₂、CA₆材料，并通过在刚玉质耐火材料基质中引入不同含量的CA₂、CA₆相，制备了CA₂／CA₆刚玉复相耐火材料，以期利用CA₂材料的低膨胀系数和CA₆材料的片状增韧机理来改善现有刚玉耐火材料的热震稳定性。本论文研究工作如下： 1．研究以轻质CaCO₃／活性氧化铝，纯铝酸钙水泥／活性氧化铝两种合成工艺路线，采用反应烧结法合成CA₂、CA₆材料，研究了反应原料、反应温度、成型压力对CA₂、CA₆材料烧结性能和物相变化的影响，观察和分析了CA₂、CA₆材料的显微结构，探讨了CA₆片状晶体结构的生长机理。 2．采用机压成型制备CA₂／CA₆刚玉复相材料。研究了纯铝酸钙水泥或CaCO₃加入量不同对CA₂／CA₆刚玉复相耐火材料的烧结性能、力学性能、物相组成、热膨胀性能及其显微结构的影响，并探讨了CA₂／CA₆刚玉复相材料的抗渣性能。 3．采用浇注成型方法制备CA₂／CA₆／刚玉复相材料。研究了纯铝酸钙水泥加入量对材料的烧结性能、力学性能、物相组成、热膨胀性能及显微结构的影响，并探讨了CA₂／CA₆／刚玉复相材料的抗渣性能。更多还原

【Abstract】 Calcium dialuminate (CA2) and Calcium hexaluminate (CA6) occur at CaO-Al2O3 system as important compounds. Composites combining CA2 with high melting point and high thermal expansion materials such as MgO and CaZrO3 show a lower thermal expansion due to the low thermal expansion coefficient of CA2. CA6 is considered as a promising material for its well stability in reducing atmospheres, improved corrosion resistance to alkali and low solubility in slag containing Fe2O3. Furthermore, thanks to the hexagonal platelet structure, well chemical consistence and similar thermal expansion coefficient with corundum, CA6 is introduced into the matrix of corundum ceramic as toughening phase.In this paper, CA2 and CA6 were synthesized respectively by reaction sintering and CA2/CA6/corumdom composite refractories were fabricated through adjusting the content of CA2 and CA6 in matrix in order to improve the thermal shock resistance of corundum refractories. What has been done in this paper is divided into three parts:The first part focuses on the sintering properties and reaction mechanism of CA2 and CA6 synthesized by two processing routes-CaCO3/ -Al2O3 and pure calcium aluminate/ -Al2O3, respectively. The effect of raw materials and compact pressures and reaction temperatures on the sintering properties of the product was studied. The microstructures of CA2 and CA6 were observed and the plantlet structure growth mechanism of CA6 was discussed.The second part focuses on the fabrication and properties of CA2/CA6//Al2O3 multiphase composites. The effect of the content of pure calcium aluminate or CaCO3 in the matrix on the sintering and mechanical properties , phase composition , thermal expansion, microstructure and slag resistance of CA2/CA6/Al2O3 multiphase composites were investigated.The final part focuses on the fabrication and properties of CA2/CA6/Al2O3 castable. The effect of the content of pure calcium aluminate in the matrix on the sintering and mechanical properties, phase composition , thermal expansion, microstructure and slag resistance of CA2/CA6/Al2O3 composites were investigated.更多还原