K. Shimoda et al./ Composites Science and Technology 68(2008)98-105 1200 uncoated 1000 CD0.25 CD-0.50 CⅤD-1.00 詞600 400 0.05 0.15 0.2 isplacement /mm Fig. 7. Typical flexural stress-displacement curves of SiC/SiC composites with various PyC interface thickness. C(s)+ SiO2(s, I)=SiC(s)+2Co(g) (4) difficult leading to porous matrix. Increasing applied pres It is reported that the densification process highly depen- sure(to 20 MPa) will enhance the sliding of Sic nano-pow- dent on hot-pressing conditions, such as sintering tempera- der. While increasing sintering temperature ( to 1800C ture and applied pressure [15, 16]. At lower temperature, will promote the liquid phase formation so that less liquid phase formation will inhibit the sliding of Sic fication is also improved. However, extra temperatu nano-powder. In this case matrix densification becomes pressure might exerted on fibers through the highly (d Fiber pull-out Fiber d-out Fig 8. Fracture surface of SiC/SiC composites with various PyC interface thickness after three-point bending test: (a)uncoated, (b) CVD-0 25 (c)CVD. 0.50and(d)CvD-1.003CðsÞ þ SiO2ðs; lÞ ¼ SiCðsÞ þ 2COðgÞ ð4Þ It is reported that the densification process highly depen￾dent on hot-pressing conditions, such as sintering tempera￾ture and applied pressure [15,16]. At lower temperature, less liquid phase formation will inhibit the sliding of SiC nano-powder. In this case, matrix densification becomes difficult leading to porous matrix. Increasing applied pres￾sure (to 20 MPa) will enhance the sliding of SiC nano-pow￾der. While increasing sintering temperature (to 1800 C) will promote the liquid phase formation so that the densi- fication is also improved. However, extra temperature and pressure might exerted on fibers through the highly densifi- Fig. 7. Typical flexural stress–displacement curves of SiC/SiC composites with various PyC interface thickness. Fig. 8. Fracture surface of SiC/SiC composites with various PyC interface thickness after three-point bending test: (a) uncoated, (b) CVD-0.25, (c) CVD- 0.50 and (d) CVD-1.00. K. Shimoda et al. / Composites Science and Technology 68 (2008) 98–105 103