| 摘要 |
PURPOSE:To obtain the silicon carbide molding which is tough and wrinklefree even if the molding is thin by crosslinking and insolubilizing a silicon carbide precursor polymer sheet, then calcining the sheet in a hanging state. CONSTITUTION:A polycarbosilane/styrene copolymer is used as the silicon carbide precursor and is heated to melt in a nitrogen atmosphere of about <=10ppm oxygen concn. the copolymer is defoamed in a vacuum of about 0.5Torr. The deformed copolymer melt is extruded from a die having a slit shape to form the sheet 1 of the polycarbosilane/styrene copolymer. This sheet 1 is placed on a wire net 2 of about 10 mesh and is heated in an air atmosphere to crosslink and insolubilize the sheet, following which the sheet is heated and calcined in a nitrogen atmosphere of about 10ppm oxygen concn. in a hanging state, by which the flat molding of the silicon carbide sheet is obtd. |
