熔盐改性多孔碳化硅陶瓷的显微结构与性能

摘要

The porous silicon carbide ceramics were surface modified with molten salts of anhydrous aluminum sulfate and sodium sulfate and the phase composition and microstructure after molten salt reaction were studied.The PM2.5 filtering performance of the porous silicon carbide ceramics before and after modification was tested.The results show that the acicular mullite whiskers with lengths of over ten microns and diameters of several hundred nanometers were produced by the reaction of the molten salts of aluminum sulfate and sodium sulfate with silicon carbide at 900 ℃.The mass concentration of PM2.5 in diesel smoke was decreased from over 280μg•m-3 to less than 150μg•m-3 after filtration by the molten salt modified porous silicon carbide ceramic,which was better than that by the unmodified porous silicon carbide ceramic (200 μg•m-3 ).The mullite whiskers can block the movement of the particulate matters in diesel smoke and make them precipitate between whiskers,resulting in the improvement of smoke filtering performance of the porous silicon carbide ceramics.%利用无水硫酸铝和硫酸钠熔盐对多孔碳化硅陶瓷进行了表面改性处理,研究了熔盐反应后的物相组成和显微结构,并测试了改性前后多孔碳化硅陶瓷对烟气中 PM2．5的过滤性能.结果表明：在900℃下,硫酸铝、硫酸钠熔盐与碳化硅反应生成针状莫来石晶须,长度达到十几个微米,直径几百个纳米；熔盐改性多孔碳化硅陶瓷将柴油烟气中PM2．5质量浓度由大于280μg•m－3降低到小于150μg•m－3,过滤效果优于未改性多孔碳化硅陶瓷的(200μg•m－3)；莫来石晶须可以阻挡烟气中颗粒物的运动,使其沉积在晶须间,提高了多孔碳化硅陶瓷对烟气的过滤性能.