Sintering and microstructural characterization of calcium alumino-titanate-bauxite-SiC composite refractories
Sintering and microstructural characterization of calcium alumino-titanate-bauxite-SiC composite refractories
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DOI：
10.1016/j.ceramint.2018.03.157
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发表时间：
2018-06
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
铝钛酸钙（CAT）是一种复合耐火材料，具有导热系数低、熔点高、耐火度高、热膨胀系数小、抗热震性好等特点。以铝土矿、过氧化氢（CAT）、SiC、α-Al 2 O3、金属硅和广西白色粘土为原料，以Al（H2 PO 4）3溶液为粘结剂，制备了CAT-铝土矿-SiC复合材料。通过X射线衍射（XRD）、扫描电镜（SEM）和热力学分析研究了其致密化行为、相变和微观结构。结果表明，由于SiC氧化和液相的形成，体积密度随温度的升高先增大后减小。此外，对于铝土矿颗粒而言，在较高温度下，铝土矿颗粒的聚集增强，并且过高的温度导致铝土矿颗粒的异常生长。此外，CAT晶粒中存在的莫来石晶须在高于1450 °C的烧制温度下开始突破液相的表面;这些晶须在1600 °C下显示出完美的结晶。最后，由于SiC氧化和钙离子扩散的增加，SiC晶粒周围的富钙（钙长石）区域的数量随着温度的增加而增加。
Calcium alumino-titanate (CAT) is a composite refractory material that exhibits a low thermal conductivity, high melting point, high refractoriness, low thermal expansion coefficient, and good thermal shock resistance. CAT-bauxite-SiC composites were prepared by using bauxite, CAT, SiC, α-Al2O3, metallic Si, and Guangxi white clay as starting materials and an Al(H2PO4)3solution as a binder. Their densification behavior, phase changes, and microstructures were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermodynamic analysis. The results show that the bulk density initially increases and then decreases with temperature because of SiC oxidation and the formation of a liquid phase. In addition, the aggregation of corundum particles is enhanced at higher temperatures for bauxite grains, and excessively high temperatures cause abnormal growth of the corundum particles. Furthermore, the mullite whiskers present in the CAT grains begin to break through the surface of the liquid phase at firing temperatures above 1450 °C; these whiskers show perfect crystallization at 1600 °C. Finally, the quantity of Ca-rich (anorthite) regions around the SiC grains increase with temperature due to an increase in SiC oxidation and calcium ion diffusion.