Study On Preparation Of Rattan-based Silicon Carbide Diphase Ceramic

In this study,the SiC diphase ceramic was prepared from Daemonorops margaritae cane according to the C-Si reaction mechanism.The prepared rattan-based SiC diphase ceramic?R-SiC?was a ceramic with high value-added,which consisted of SiC,unreacted biomass charcoal and SiO₂ and had great practical significance to broaden the application of rattan resources.In order to optimize the preparation process of R-SiC,the effects of different preparation method,preparation and impregnation process of the SiO₂ sol,and the pyrolysis parameter on the phase,chemical composition,micro-morpholoy and element distribution of SiC diphase ceramic were characterized by X-ray diffraction?XRD?,Fourier transform infrared spectroscopy?FT-IR?,X-ray fluorescence?XRF?,N2 physisorption,field emission environmental scanning electron microscope?FESEM?,transmission electron microscopy?TEM?and energy dispersive X-ray analysis?EDAX?,etc..The main contents and results were listed as follows:?1?R-SiC derived from elemental silicon powder,SiO₂ sol and rattan powder was prepared via liquid Si-melt infiltration method?LSI?and Sol-Gel method?Sol-Gel?,respectively.The results showed that the content of SiC and the specific surface area of R-SiC prepared by Sol-Gel?R-SiCSiO₂?was 24.57% and 21.99 m2/g,respectively.The content of SiC and the specific surface area of R-SiC prepared by LSI?R-SiCSi?was 23.28% and 6.25 m2/g,respectively.Sol-Gel can reserve the porous structure of rattan in R-SiCSiO₂,while it was difficult for LSI to reserve the same porous structure in R-SiCSi.Compared with LSI,R-SiC prepared by Sol-Gel possessed more intact porous structure,higher SiC yield and specific surface area,and Sol-Gel was superior on the preparation of porous SiC diphase ceramic.?2?SiO₂ sol was prepared from the raw material of tetraethoxysilane?TEOS?,absolute ethyl alcohol?EtOH?and distilled water?H2O?under the catalysis of hydrochloric acid or ammonia water.The results showed that the stability,solid content,viscosity and impregnation performance of SiO₂ sol prepared under the catalysis of hydrochloric acid was 24.33 h,15.90%,7.14 mPa·s and 8.75%,respectively.And the solid content,viscosity and impregnation performance were superior to the corresponding value of alkaline SiO₂ sol.The orthogonal experiment was applied to investigate systematically the effect of the raw material ration and the pH value on the stability,solid content,viscosity and impregnation performance of acid SiO₂ sol.And the process parameter of n?TEOS?: n?EtOH?: n?H2O?=1: 4: 6 and pH=2.5 was optimized to prepare Si O₂.The performances of acid SiO₂ sol under ultrasound-assisted treatment for different time were investigated to acquire the optimized treatment time of 10 min.?3?R-SiC was prepared by Sol-Gel and by adjusting the pyrolysis temperature and holding time of one-step pyrolysis process.The results showed that R-SiC prepared at different pyrolysis parameters could retain the porous structure of rattan.The density of R-SiC would decreased,and the specific surface area as well as SiC yield of R-SiC would increased as the temperature rised and the holding time extended.R-SiC prepared at 1500? for 120 min possessed the minimum density?0.25 g/cm3?,and the maximum specific surface area?43.38 m2/g?and SiC yield?44.24%?.SiC whisker was the major SiC morphology existing on the cross section of R-SiC.