Al2O3–MgAl2O4复合多孔陶瓷支撑体的制备及性能

Preparation and Characterization of Composite Porous Ceramic Supports from Alumina and Magnesium Aluminate Spinel

以工业级氧化铝和镁铝尖晶石为原料、石墨为造孔剂,通过干压法制备Al2O3–MgAl2O4复相多孔陶瓷支撑体。研究了原料配比、烧结温度和造孔剂含量对支撑体孔隙率、力学性能、孔径分布及耐酸碱腐蚀性的影响。结果表明：当Al2O3含量为90%（质量分数）、Mg Al2O4含量为10%、外加20%石墨时,在1 478℃烧结,制得的支撑体孔隙率为37.6%,抗弯强度为83.11 MPa,优于同等条件制备的Al2O3纯相支撑体的力学性能,该复相支撑体分别在80℃、10%的硫酸和氢氧化钠溶液中腐蚀24 h后,剩余抗弯强度为59.69和71.25 MPa,表明添加适量的Mg Al2O4,除了可以增加抗弯强度,可以提高其耐碱性能。

The composite porous ceramic support was fabricated by a dry pressing method using industrial A12O3 and MgA12O4 as raw materials and graphite as a pore-forming agent. The effects of compositions, sintering temperature and graphite content on the porosity, flexural strength, pore size distribution and chemical resistance were investigated. The results show that the support with Al2O3 of 90% （in mass fraction）, MgA12O4 of 10%, and excess graphite of 20% sintered at 1 478 ℃ has a porosity of 37.6% and a flexural strength of 83.11 MPa respectively, which is better than those of the pure A1203 support. Also, the flexural strength decreases from 83.11 to 59.69 MPa when the support immerses in 10% H2SO4 at 80 ℃ for 24 h. In contrast, the flexural strength becomes 71.25 MPa after it immerses in 10% NaOH solution at 80 ℃ for 24h. It is indicated that adding a certain amount of MgA1204 can increase the flexural strength, and improve the resistance to alkali solution.