Preparation Of Macroporous SiC Woodceramics And Performance Exploration

Woodceramics is a new kind of ecomaterials being developed in recent years. As a porous carbon material, it is made from wood or woody materials impregnated with thermosetting resin such as resin in a vacuum furnace. Woodceramics was reported to have many excellent performances such as good electrical, friction and wear resistance, corrosion resistance, high strength, lightweight and porousness, electromagnetic shielding ability, and therefore, it has potential application in many industries. However, the problems of costly raw material and anisotropy of structure about woodceramics haven't solved until now, they obstructed the development of woodceamics and extending application fields of woodceramics.So, this paper reviews the fabrication methods of woodceramics based on different raw material and different technology. And then two new technology have been developed to prepare woodceramics using the waste material of wood and epoxide resin as row materials. One is that wood meal,Si powder and epoxide resin are mixed up with magnetic stirrer, then get SiC porous woodceramics by sintering. The other is get the woodceramics first, then dipping SiO₂ collosol and get SiC porous woodceramics by sintering last.Thermo-gravimetric analysis was applied to reveal the pyrolysis behaviors of wood powder and epoxide resin. X-ray diffraction,Scanning electron microscopy and FT-IR were employed to characterize and analyze phase identification,the microstructures and the chemical construction of SiC porous woodceramics. Apparent porosity of SiC porous woodceramics were revealed by Archimend's law. And solid content viscosity of colloidal were also analysed. The result show that the SiC porous woodceramics can prepared by two ways. The woodceramics have quasi-log tracheid microstructure and graphite microcrystallite is create in high sintering temperature. Apparent porosity are inverse relation with sintering temperature and direct relation. The solid content of collosol is 23.6% and the standing time is less than 72h. The SiC porous woodceramics are complex material with carbon and silicon carbide.In addition, the effect of sintering temperature and constituent content on mechanical property of SiC porous woodceramics are analysed. The effect of sintering temperature,constituent contents speed of heating-up,loading weightand and the speed of friction on tribology performance are also analysed. Analyse the wear extent and grinding crack of every stage. The result show that the best technological conditions are as follow, sintering temperature is high than 1300°C, the speed of heating-up is below 5°C/min¹0°C/min, and the the content of Si is low. Spalling carbon grain in wearing can fill up the cavern of woodceramics, with increasing of wearing-in period the carbon grain refining and form thin film, which can reduce wearing capacity availably. The best condition of abrasion is high speed and low load, and the abrasion became stabilization abrasion after four or five hour.