碳含量及类型对镁碳耐火材料弹性模量的影响

Effect of carbon contents and types on elastic modulus of MgO-C refractories

采用声频法测量经不同热处理温度后镁碳耐火材料的弹性模量,并测量了气孔率以及常温弯曲强度,同时进行了热震实验,用XRD和SEM并辅助EDX分析了试样的物相组成及显微结构的变化,评估碳含量及类型对镁碳耐火材料抗热震性的影响。结果表明:随着石墨含量的降低,材料的弹性模量不断升高;含炭黑试样的弹性模量低于含石墨试样,使其具有更好的热震稳定性。随着热处理温度的升高,气孔率不断升高并导致弹性模量的不断降低;抗氧化剂Al粉与电熔镁砂反应生成的MgAl2O4相使得弹性模量在1 000,1 400℃出现稍许增加。

In order to study the effect of carbon contents and types on the elastic modulus of MgO-C refractories, the elastic modulus of MgO-C refractories after heat-treatment at different temperatures was measured, the porosity and bend strength were measured, and thermal shock experiments were carried out. The phase composition and microstructure changes of specimens were analyzed by XRD, SEM and EDX. The results show that with the content of graphite decreasing, the elastic modulus of specimens increases; the elastic modulus of the specimen containing carbon black is lower than that containing graphite, which results in better thermal shock resistance. With the increase of heat-treatment temperature, the porosity of specimen increases, which leads to the continuous reduction of elastic modulus. The MgAl2O4 phase resulting from the reaction of antioxidants A1 powder and fused magnesia leads to a slight increase of elastic modulus at 1 000 and 1 400 ℃.