汽车尾气净化器中活性氧化铝涂层性能改进综述

摘要

介绍了汽车尾气净化器中活性氧化铝涂层的基本概况,简述了制备活性氧化铝涂层的不同方法的改进效果,表明溶胶-凝胶法制备出的活性氧化铝比表面积较大且杂质很少,但其在工业化进程中需要进一步优化加水量、溶剂种类、pH值、陈化时间等影响因素的工艺条件;在分析添加剂对活性氧化铝涂层性能改善机理的基础上,综述并比较了稀土元素、碱土金属、SiO2及其他添加剂对涂层性能的影响效果,可知在活性氧化铝涂层中引入添加剂可以增加涂层的比表面积、抑制活性氧化铝的晶型转变、提高涂层的高温稳定性能,指出同时添加La,Ba可以使活性氧化铝得到更好的热稳定性.因此,溶胶-凝胶法和同时掺杂La,Ba是活性氧化铝涂层性能改善研究的发展方向.%The basic situation of activated alumina coating in automobile exhaust gas purifier is introduced.The improvement effect of different methods for preparing active alumina coating is described.It is shown that the activated alumina prepared by sol-gel method has large specific surface area and impurity, but it still needs to further optimize the process conditions of the influencing factors such as water addition, solvent type, pH value and aging time in the process of industrialization.Based on the analysis of the mechanism of the additive in improving the performance of the activated alumina coating, the effects of rare earth elements, alkaline earth metals, silica and other additives on the coating performance are reviewed and compared.It can be seen that the introduction of additives in the active alumina coating can increase the specific surface area of the coating, inhibit the crystalline transformation of the activated alumina, and improve the high temperature stability of the coating.It is pointed out that the addition of lanthanum and barium can make the thermal stability of activated alumina better.Therefore, it is proposed that the development directions of activated alumina coating be sol-gel method with doping La and Ba.