Cr2O3微粉加入量对Al2O3-Cr2O3质耐火材料性能的影响

以电熔铬刚玉和白刚玉为主要原料,用Cr₂O₃微粉部分替代电熔铬刚玉细粉,研究了Cr₂O₃微粉加入量对Al₂O₃-Cr₂O₃质耐火材料常温和高温性能、物相组成和显微结构的影响。结果表明,随着Cr₂O₃微粉加入量的增加,原位形成了(Al_1-xCr_x)₂O₃固溶体,促进了烧结,材料的显气孔率先降低后升高,且(Al_1-xCr_x)₂O₃固溶体的晶格常数呈线性增加,符合Vegard定律。材料的常温抗折强度和常温耐压强度随Cr₂O₃微粉加入量的增加先升高后降低,在Cr₂O₃微粉加入量为15%(质量分数)时强度达到最大值。而当Cr₂O₃微粉加入量为20%(质量分数)时,由于有挥发现象,材料显气孔率上升,强度下降。材料高温抗折强度随Cr₂O₃微粉加入量的增加而增加,材料的残余强度保持率呈先降低后升高的趋势。

Effect of Addition of Cr2O3 Micropowder on Properties of Al2O3-Cr2O3 Refractory

The effect of the addition of Cr₂O₃ micropowder on the normal temperature and high temperature performances, phase composition and microstructure of Al₂O₃-Cr₂O₃ refractories was studied by using fused chromium corundum and white corundum as the main raw materials, and using Cr₂O₃ micropowder to partially replace the fused chromium corundum fine powder. The results show that with the increase of the addition of Cr₂O₃ micropowder, (Al_1-xCr_x)₂O₃ solid solution is in-situ formed, which promotes sintering. And the apparent porosity of the material decreases first and then increases. The lattice constant of (Al_1-xCr_x)₂O₃ solid solution increases linearly with the increase of the addition of Cr₂O₃ micropowder, which conforms to Vegard’s law. The cold modulus of rupture and cold compressive strength increase first and then decrease with the increase of the addition of Cr₂O₃ micropowder. When the addition of Cr₂O₃ micropowder is 15% (mass fraction), the strength of the material reaches the maximum value. When the addition of Cr₂O₃ micropowder is 20% (mass fraction), the apparent porosity of the material increases and the strength decreases due to volatilization. The hot modulus of rupture of the material increases, and the residual strength rate of the material decreases first and then increases with the increase of the addition of Cr₂O₃ micropowder.