Carbon fiber reinforced ceramics (CFRCs) were prepared from PAN based carbon fiber (CF) and aluminum-phosphate solution (ACIDOPHOS 120M: ACP) as a matrix precursor.
ACP was easily impregnated for CF, because it was water soluble. Therefore, these CFRCs showed high-volume fiber contents. As a result, it gave higher mechanical properties of CFRCs.
The unidirectional sheets of high performance carbon fibers impregnated with ACP were dried at 80°C to make the prepreg sheets. These prepreg sheets then were laminated into CFRC plate by a hot-press molding (processing pressure>10MPa, maximum processing temperature from 200 to 280°C) and were subsequently heated in Argon up to 500°C.
Addition of small amounts of metal oxides, for example: Al2O3 (10 wt %) or MgO (2 wt %) or ZnO (4 wt %) into the ACP remarkably improved the operation efficiency.
The result of X-ray analyses indicate that the 500°C heat-treated matrices were mainly composed of aluminum phosphate (AlPO4) and certain amount of amorphous contents. But the amorphous contents was slightly observed in the matrix which was added with Al2O3.
The obtained CFRCs exhibited the following characters: fiber volume of 40-50 wt %, maximum bending strength of 553 MPa, and maximum bending modulus of 80 GPa.
