May 2004 Mullite(3Al,03 2SiO2/ -Aluminum Phosphate (AlPO4, Oxide, Fibrous Monolithic Composites 1 mm ma (b) Fig. 8. Optical micrographs of the green pellets: (a) three-layer structure, (b)mixed 50% two-layer: 50% three-layer structure 50 microns 9. SEM micrographs of the sintered, two-layer, mullite-AlPO4 fibrous monolithic composite (M: matrix(mullite), 1: interphase(AIPO), arrows ate the circumferential cracks formed around mullite center rods 300 microns人 50 microns 10. SEM micrographs of the sintered, three-layer, mullite-AlPOa fibrous monolithic composite(M: matrix(mullite); I: interphase(AlPO4)Fig. 8. Optical micrographs of the green pellets: (a) three-layer structure, (b) mixed 50% two-layer:50% three-layer structure. Fig. 9. SEM micrographs of the sintered, two-layer, mullite–AlPO4 fibrous monolithic composite (M: matrix (mullite); I: interphase (AlPO4); arrows indicate the circumferential cracks formed around mullite center rods). Fig. 10. SEM micrographs of the sintered, three-layer, mullite–AlPO4 fibrous monolithic composite (M: matrix (mullite); I: interphase (AlPO4)). May 2004 Mullite (3Al2O3
2SiO2)–Aluminum Phosphate (AlPO4), Oxide, Fibrous Monolithic Composites 799