Porous Silicon Carbide Ceramic Prepared from Bamboo and Study on the Electromagnetic Wave Absorption Properties of It
After thousands of years’ natural evolution, wood and bamboo are endowed with unique structure and performance. After proper physical or chemical treatment, they can be used to prepare ceramic material with controllable structure and excellent performance and the structure and performance is programmable. At present the most reports in literature are to synthesize ceramic with wood. With the increasingly serious global environment problems, the enhancement of human environment protect consciousness and the startup of Chinese natural forest protect project, the conflict between supply and demand of domestic wood is increasingly serious. Bamboo can grow quickly, regenerate fast and easily and can be continually used after successful forestation. So it is an important approach to replace wood with bamboo to relax the conflict between supply and demand of wood and protect the environment.Ceramic block and powder of SiC was prepared through sol-gel and liquid silicon infiltration with bambusa arundinacea and bamboo charcoal powder as raw material. Wave-adsorption material was also prepared by the infiltration of magnetic metal. The phases, morphology and RAM reflectivity was characterized by XRD, SEM, EDX, TEM and RAM reflectivity testing system.Results show that the bamboo charcoal and the final SiC ceramics both inherit the porous microstructure of bamboo. The reaction from carbon to ceramic occurred mainly on the wall of the holes. Ceramic whiskers appear in some holes when using sol-gel method. The conversion rate from bamboo charcoal to SiC and the the degree of crystallization can be improved by increasing the reaction temperature and prolonging the time of the highest temperature in liquid silicon infiltration method. But the conversion rate can not be improved by increasing the reaction temperature and prolonging the time of the highest temperature in sol-gel method. The restrict factor of the conversion rate is the infiltration effect during the sol infiltration step. The conversion rate from charcoal to ceramic of bamboo charcoal powder is higher than 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.