| 摘要 |
PROBLEM TO BE SOLVED: To obtain a filament reinforced SiC composite material having high density, excellent in strength and fracture toughness and usable even in a severe environment in which superheat resistance at >=1,600 deg.C is required. SOLUTION: High mol.wt. polycarboxilane exclusive of a low mol.wt. component whose mol.wt. is <=1,000 and a vinyl group-contg. silicone polymer whose mol.wt. is >=10,000 are dissolved in an org. solvent, two or more kinds of SiC powders different from each other in particle diameter are added to the resultant soln. optionally in combination with fine Si powder having <=4μm particle diameter and they are mixed and dispersed to prepare a slurry. Prepreg sheets are formed using the slurry and ceramic long fibers having heat resistance at >=1,600 deg.C as a filler and they are degassed, laminated and compacted to form a green compact. This compact is calcined in an inert atmosphere and formed by hot pressing. Densification is then carried out if necessary as follows; fine SiC and/or Si powder having <=4μm particle diameter is added to high mol.wt. polycarbosilane exclusive of a low mol.wt. component whose mol.wt. is <=1,000 in the presence of an org. solvent and they are mixed and dispersed and the resultant slurry is impregnated and the solvent is removed and firing is carried out and these processes are repeated. |
