竹材制备SiC多孔陶瓷及吸波性能研究

PREPARATION AND WAVE-ADSORPTION PROPERTIES OF POROUS SiC CERAMIC FROM BAMBOO-BASED MATERIALS

以印度竹和竹炭粉为原料,采用溶胶凝胶法和液态渗硅法制备生物基SiC陶瓷块和陶瓷粉,并通过磁性金属担载制备了吸波材料。借助XRD、SEM、RAM反射率测试系统对材料的物相构成、微观构造、吸波反射率进行了分析。结果表明:竹材炭化及陶瓷化后均保持了多孔的骨架结构特征。溶胶凝胶法和液态渗硅法的陶瓷化反应都发生在竹炭孔道侧壁上,且溶胶凝胶法在竹炭孔道内部有硅基陶瓷晶须生成。要提高液态渗硅法竹炭向SiC的转化率和SiC的晶化程度,可以通过提高陶瓷化温度和延长保温时间的方法来实现。无论何种方法,竹炭粉比竹炭块的陶瓷转化率高。另外通过溶胶凝胶法制备的担载磁性金属的竹基陶瓷材料在低频波段有一定的电磁波吸收性能。

Ceramic block and powder of SiC were prepared through solgel and molten silicon infiltration processes with bambusa arundinacea and bamboo charcoal powder as the raw materials. Waveadsorption material was also prepared by the infiltration of magnetic transition metal The phases, morphology and RAM reflectivity of the obtained materials were characterized by XRD, SEM, EDS and RAM reflectivity testing systerm. Results showed that both the bamboo charcoal and the final SiC ceramics inherit the porous microstructure of the original bamboo. The reaction from carbon to ceramic occurred mainly on the wall of the holes, Ceramic whisker appeared in some holes when using solgel method. Both the conversion rate from bamboo charcoal to SiC and the degree of crys- tallization of SiC can be improved by increasing the reaction temperature and the maintaining time in molten silicon infiltration method. The conversion rate from bamboo charcoal powder to ceramic is higher than that from bamboo charcoal block in whatever method. The porous ceramic with SiC whiskers in some holes prepared by sol-gel method show some electromagnetic wave adsorption properties in the low frequency band.