CuO-TiO_2对多孔氧化铝陶瓷支撑体性能的影响

以α-Al2O3为骨料,羧甲基纤维素(CMC)为造孔剂和粘结剂,丙三醇为润滑剂和增塑剂,CuO-TiO_2为烧结助剂,采用挤压成形和固态粒子烧结法制备管式多孔氧化铝陶瓷支撑体。通过X线衍射(XRD)、扫描电镜(SEM)、抗折强度测试等,研究CuO-TiO_2对氧化铝陶瓷支撑体的晶相组成与微观形貌、孔隙率、抗折强度、耐酸/碱腐蚀等性能的影响。结果表明:TiO_2与Al2O3固相反应生成Al2TiO5,并生成大量正离子空位而提高扩散系数,促进氧化铝陶瓷的致密化,同时CuO的液相润湿作用使TiO_2的固溶温度降低,生成液相低共熔物CuAl2O4,进而实现低温烧结。当TiO_2与CuO的添加量(质量分数)分别为3%和1.5%、烧结温度为1200℃时,获得孔隙率为33%、抗折强度104.4MPa、酸/碱腐蚀后的质量损失率为0.02%/0.09%的性能优异的管式多孔氧化铝陶瓷支撑体。

Effect of CuO-TiO2 on the properties of porous alumina ceramics support

Tubular porous alumina ceramic support withα-Al2O3as aggregate, carboxymethyl cellulose (CMC) as pore-forming agent and binder, glycerol as lubricant and plasticizer, and CuO-TiO2as sintering agent was prepared by extrusion-forming and solid sintering method. The effects of CuO and TiO2on the crystal phase composition and microstructure, the porosity, flexural strength, and the acid and alkali corrosion of the alumina ceramic support were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and flexural strength test. The results show that TiO2 reacts with Al2O3 and forms Al2TiO5solid solution, and the diffusion coefficient increases largely with the augment of Al3+ vacancy concentration which promotes the densification of alumina ceramics. Meanwhile, the reaction temperature of TiO2with Al2O3can be lowed with the effect of liquid wetting of CuO, and the generated liquid eutectic mixture CuAl2O4 is helpful to realize low temperature sintering. When the addition of TiO2 and CuO (mass fraction) are 3% and 1.5%, respectively, and the sintering temperature is 1200℃, the tubular porous alumina support with the porosity of 33%, flexural strength of 104.4 MPa, and acid /alkali corrosion weight loss of 0.02%/0.09% can be obtained.