MgO-MgAl_2O_4-MgAlON系复合材料的制备及性能研究

Study on preparation and mechanical property of MgO-MgAl_2O_4-MgAlON composites

分别以60%(w)的电熔镁砂或(和)电熔镁铝尖晶石为骨料,以40%(w)的Al-Al2O3-MgO混合粉(采用Al粉、活性α-Al2O3和MgO粉按质量比4∶9∶1混合)为基质料,在N2气氛中于1500℃6h反应烧结制备了MgO-MgAlON、MgO-MgAl2O4-MgAlON和MgAl2O4-MgAlON三种复合材料,并研究了材料的烧结性能、高温力学性能、物相组成以及显微结构。结果表明在本试验范围内,3种材料的烧结性能相差不大,1500℃氮化烧成后均达到致密烧结状态;材料的HMOR-T曲线属于I类曲线,且热态抗折强度(≤1400℃)均高于常温强度,强度峰值的对应温度均为1200℃。所制备的3种复合材料相比较,MgAl2O4-MgAlON复合材料的综合性能最优。

With Al - Al2O3 - MgO （ the ratio of Al powder, active Al2O3 and MgO powder is 4：9 ： 1 ） system mixture powder as matrix materials （the mass percent is 40% ） and fused magnesia,fused magnesia -alumina spinel （the mass percent is 60% ） as aggregates, the MgAlON bonded composites including MgO - MgAlON, MgO-MgAl2O4 -MgAlON and MgAl2O4 -MgAlON were prepared in nitrogen atmosphere at 1500 ℃ for 6 h. The sintering properties, phase compositions,microstructures and hot modulus of ruptures of the composites were investigated. The results indicate that the dense composites could be obtained after being sintered at 1500 ℃. As for the sintering properties,there were not any obvious differences among the three materials. The HMOR - T curves belongs to type I and the hot（ ≤ 1400 ℃）strength is higher than that at room temperature. The peak of the strength was formed at 1200 ℃. Among the three materials,the MgAl204 -MgAlON composite has the best property.