尖晶石含量对轻量化方镁石-尖晶石浇注料显微结构和性能的影响

发布时间：2018-08-31 10:09

【摘要】：以多孔方镁石-尖晶石陶瓷为骨料,以97烧结镁砂、刚玉和70尖晶石等细粉为基质,通过改变浇注料中预合成尖晶石的质量分数(分别为0wt.%、8.5wt.%、16.3wt.%和26.5wt.%),制备了四组轻量化方镁石-尖晶石浇注料。采用急冷法测试样的抗热震性能,借助弹性模量测量仪检测试样热震前后的弹性模量,并使用SEM、EDS和Fact Sage?热化学软件研究了尖晶石含量对轻量化方镁石-尖晶石浇注料显微结构和性能的影响。研究发现:试样的力学性能受骨料/基质界面结构及基质的物相组成双重的影响,随着尖晶石含量增大,基质的中位孔径逐渐减小,耐压强度呈现先增大后减小的趋势;由于方镁石与尖晶石相的热膨胀系数差异使各物相间存在一些"微裂纹",此微裂纹和材料中微孔可以吸收裂纹扩展能,以阻碍裂纹的进一步扩展,当尖晶石含量由8.5wt.%增大到26.5wt.%时,热震试验后试样的弹性模量及弹性模量保持率均逐渐增大;当尖晶石含量为26.5wt.%时,轻量化方镁石-尖晶石浇注料热震后弹性模量保持率最高,抗热震性能最佳。
[Abstract]:Porous periclase spinel ceramics were used as aggregates, and 97 sintered magnesia, corundum and 70 spinel powders were used as the matrix. Four groups of lightweight periclase spinel castables were prepared by changing the mass fraction of presynthetic spinel in castable (0 wt. / 8.5wt.% and 26.5wt.% respectively). The thermal shock resistance of the samples was tested by the rapid cooling method, the elastic modulus before and after the thermal shock was measured by means of the elastic modulus measuring instrument, and the SEM,EDS and Fact Sage? were used to measure the elastic modulus of the samples before and after the thermal shock. The effect of spinel content on microstructure and properties of lightweight periclase-spinel castable was studied by thermochemical software. It is found that the mechanical properties of the samples are affected by the interface structure of aggregate / matrix and the phase composition of the matrix. With the increase of spinel content, the median pore size of the matrix decreases gradually, and the compressive strength increases first and then decreases. Due to the difference of thermal expansion coefficient between periclase and spinel phase, there are some "microcracks" between the phases. The microcracks and micropores in the materials can absorb the crack growth energy to hinder the further crack propagation. When the spinel content increased from 8.5 wt.% to 26.5 wt.%, the modulus of elasticity and the retention rate of elastic modulus increased gradually after thermal shock test, and when the content of spinel was 26.5 wt.%, the retention rate of thermal elastic modulus of lightweight pericloride-spinel castable was the highest. The thermal shock resistance is the best.
【作者单位】：武汉科技大学省部共建耐火材料与冶金国家重点实验室;
【基金】：湖北省自然科学基金重点项目(2015CFA122) 武汉市青年科技晨光计划项目(2016070204010108)
【分类号】：TQ175.732

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