两种高岭土的相组成及其对型壳抗弯强度的影响

Phase Composition of Two Kinds of Kaolin and Their Influence on the Flexural Strength of the Shell

高岭土是精密铸造型壳用耐火材料,本文研究了煤系（1^#）和非煤系（2^#）两种高岭土的物相组成及其对型壳抗弯强度的影响。利用XRD和DSC分析了两种高岭粘土粉末的相组成和热力学特性,利用三点抗弯法测试了型壳的常温、高温和溃散强度,并利用XRD和SEM对测试后的型壳进行了微观结构和断口形貌分析。结果表明,两种高岭土型壳均含有莫来石及方石英相,而2^#高岭土型壳中还含有石英相;尽管常温强度相近,但2^#高岭土型壳的高温强度和溃散强度更高。

Kaolin is an important refractory of investment casting molding shell, coal series （No.l） and non-coal series （No.2） Kaolin have been contrasted with their phase composition and impact on the flexural strength of the shell. The phase structure and thermodynamic characteristics of two kinds of Kaolin powders were analyzed by the means of XRD and DSC. The strengths of the shell at room temperature, high temperature and retained strength were studied by three-point bending test respectively. The phase compositions and microstructure of ceramic shells after mechanical testing were investigated by the means of XRD and SEM. The results show that both of refractories have mullite and cristobalite, No2. Kaolin has quartz as well. At room temperature, the strength of two kinds of shell is almost identical. But No.2 Kaolin has higher high temperature strength and retained strength.