高温CO气氛下莫来石轻质耐火材料组成、微结构演变与物理性能的相关性

This project is based on the high temperature service environment of light-weight refractories. The performance deterioration and damage are detected for mullite light-weight refractory served in the carbon monoxide atmosphere at high temperature. Thus, the composition, microstructure and creep behavior of the specimens treated in carbon monoxide atmosphere were investigated. In addition, the thermal conductivity and thermal shock resistance of the specimens suffered from creep test were discussed. Evolution of the composition and microstructure of the solid skeleton, pore parameters and the occurrence of impurity elements were revealed. Besides, the creep constitutive equation of the mullite light-weight refractory treated in carbon monoxide atmosphere was established and the influence mechanism was verified. Correlations between the pore parameters of specimens with creep deformation and thermal conductivity and thermal shock resistance were clarified by using the fractal theory, finite element calculation and grey relational analysis. This will provide new content to designing light-weight refractory with long life and high safety and the basic theory of predicting operation life.

本项目以轻质耐火材料的高温服役环境为背景，针对莫来石轻质耐火材料高温CO气氛下服役性能衰退和损毁问题，研究莫来石轻质耐火材料CO气氛热处理后的组成/微结构、蠕变行为及蠕变后的导热系数和热震稳定性。揭示高温CO气氛下莫来石轻质耐火材料固体骨架组成、微结构、孔隙参数以及杂质元素赋存形式演变规律，建立蠕变本构方程并阐明其影响机制，通过分形理论、有限元计算和灰色关联分析等方法阐释蠕变后孔隙结构参数与导热系数以及热震稳定性的相关性。为设计长寿命、高安全系数轻质耐火材料和预测其使用寿命的基础理论增加新的内容。

本项目以轻质耐火材料的高温服役环境为背景，针对莫来石轻质耐火材料高温CO气氛下服役性能衰退和损毁问题，研究了莫来石轻质耐火材料CO气氛热处理后的组成/微结构、蠕变行为及蠕变后的导热系数和热震稳定性以及不同化学成分对其在CO气氛热处理中的作用。发现导致莫来石轻质耐火材料损毁的原理为在高温CO气氛下，莫来石晶界处玻璃相中SiO2被CO消耗后导致杂质成分的富集，促进了液相的产生，液相进一步侵蚀莫来石晶粒，导致其抗蠕变和抗热震稳定性降低并发生损毁。且作为易产生液相的Fe2O3和TiO2的加入会使得莫来石更易被侵蚀，同时富铝莫来石相较于富硅莫来石经高温CO气氛侵蚀后具有一定优势。为设计长寿命、高安全系数轻质耐火材料和预测其使用寿命的基础理论增加新的内容。