喷雾干燥法制备氧化铝多孔陶瓷的工艺与性能研究

发布时间：2019-06-11 10:26

【摘要】：多孔陶瓷不仅具有普通陶瓷化学稳定性好、刚度高、耐高温、耐腐蚀等优良特性,还具有低导热性、对液体和气体的选择透过性,以及能量吸收或阻尼等性能,已经在隔热、换热、分离过滤、催化剂载体、储能、电极、隔音吸声、生物植入等许多方面发挥了重要作用。 本文结合了颗粒堆积工艺和添加造孔剂工艺,利用喷雾干燥工艺将亚微米级的氧化铝粉体制备成近似球形的含有凹陷孔洞结构的二次颗粒,同时使造孔剂与氧化铝粉体分散均匀,然后经过模压成型、烧结制备成多孔氧化铝陶瓷,具有较高的孔隙率及强度,可用作刚性隔热材料。 本文详细研究了制备过程中的各种工艺参数,测试了其气孔率及压缩强度,并用激光共聚焦显微镜观察了粉体及多孔陶瓷的形貌。实验结果表明,pH值为3,粘结剂含量为1%时,浆料的粘度在20mPa·s以下,适合于喷雾干燥。增加浆料的固含量,制备的粉体的粒径增大,颗粒间孔隙尺寸增大,有利于增大气孔率,降低材料的强度,但固含量增大至40%后,颗粒逐渐趋近于球形,内部凹陷减少,气孔率降低,强度增加。增加造孔剂加入量及降低烧结温度,都会增加多孔陶瓷的气孔率,降低其强度。 正交试验证明烧结温度对多孔陶瓷的性能影响最大,其次固含量对气孔率的影响较造孔剂高,对强度的影响较造孔剂低。综合考虑多孔陶瓷的气孔率及强度,本文最终确定的最优方案为固含量40%、粘结剂含量10%、烧结温度1400℃,该条件下制备的多孔氧化铝陶瓷气孔率为60.8%,压缩强度81.0MPa。
[Abstract]:Porous ceramics not only have good chemical stability, high stiffness, high temperature resistance, corrosion resistance and other excellent properties, but also have low thermal conductivity, liquid and gas penetration, as well as energy absorption or damping and other properties, which are already in thermal insulation. Heat transfer, separation and filtration, catalyst support, energy storage, electrode, sound insulation and sound absorption, biological implantation and many other aspects play an important role. In this paper, the submicron alumina powder was prepared into a spherical secondary particle with concave pore structure by spray drying process combined with the process of particle stacking and adding pore-making agent. At the same time, porous alumina ceramics were prepared by molding and sintering, which has high porosity and strength and can be used as rigid thermal insulation material. In this paper, various technological parameters in the preparation process were studied in detail, and their porosity and compression strength were measured. The morphology of the powder and porous ceramics was observed by laser confocal microscope. The experimental results show that when the pH value is 3 and the binder content is 1%, the viscosity of the slurry is below 20mPa 路s, which is suitable for spray drying. With the increase of solid content of slurry, the particle size of the prepared powder increases and the pore size between particles increases, which is beneficial to increase the porosity and reduce the strength of the material. However, when the solid content increases to 40%, the particles gradually approach the sphere and the internal depression decreases. The porosity decreases and the strength increases. The porosity and strength of porous ceramics will be increased and the strength will be reduced by increasing the amount of pore-making agent and decreasing the sintering temperature. Orthogonal test shows that sintering temperature has the greatest influence on the properties of porous ceramics, and secondly, the effect of solid content on porosity is higher than that of pore-making agent, and the effect on strength is lower than that of pore-making agent. Considering the porosity and strength of porous ceramics, the optimum scheme determined in this paper is solid content 40%, binder content 10%, sintering temperature 1400 鈩，

本文编号：2497118