热处理温度对连铸用Al_2O_3-C材料性能及显微结构的影响

Effect of Heat Treatment Temperature on Properties and Microstructure of the Al_2O_3-C Materials Used in the Continuous Casting

以板刚玉、天然鳞片石墨为原料，单质硅粉为抗氧化剂，酚醛树脂为结合剂，采用等静压成形工艺制备了连铸用Al2O3-C材料，分别在不同温度（700、900、1100、1300、1500℃）下处理。研究了不同热处理温度对连铸用Al2O3-C材料性能及显微结构的影响，结果表明：随着热处理温度的升高，材料残余线变化先减小后增大，1500℃热处理后试样为膨胀状态，其他均为收缩状态；显气孔率逐渐升高，体积密度逐渐降低，但二者变化幅度均不大；常温及高温强度均呈现先升高后降低的趋势，1300℃热处理后强度最高，热处理温度在9001300℃之间时，材料呈现优良的力学性能；高于1100℃的热处理试样内有碳化硅晶须生成，且热处理温度越高，碳化硅晶须的生成量越多，晶须直径越粗大。

Samples of Al2O3-C materials used in the continuous casting were prepared by the cold isostatic press machine, based on the tabular corundum and natural squama graphite as raw materials, Si as antioxidant and phe- nolic resin as binder. The physical properties and microstructure of the samples burnt in different temperature （700, 900, 1100, 1300, 1500 ℃） were determined. The results shows that., with the heat treatment temperature increasing, the residual linear change of the samples firstly decreases and then increases, and sample burnt at 1500℃ be- comes expansion; the apparent porosity rate gradually increases and the body density decreases, while the changes are modest; the room temperature and the high temperature strength increases firstly and then decreases, and the strength of sample burnt at 1300℃ is the highest. The mechanical properties of the Al2O3-C materials perform well when the heat treatment temperature is from 900 to 1300 ℃. The production of SiC whisker is more and the diameter of SiC whisker is bigger when the heat treatment temperature is increasing.