Y. Liu et aL/Corrosion Science 51(2009)820-826 Coating defect 500m Cracking self-sealing Surface 0 Surface pores Glass crystallization 100um 500m Fig 4. Surface morphologies of CVD Sic/a-BC/ SiC coatings after oxidized at different temperatures. (a)and (b)at 700C, (c)and(d)at 1000C, and (e)and(n)at 1200.C, 50 1200°c 1000° 2-。m 多-03-01000 A-1200℃ 700°c 102030405060708090100 Time(h) Fig. 6. Weight changes of the coated composites oxidized at different temperatures Fig. 5. XRD patterns of multilayer SiC/a-BCSiC coating surface after oxidation. SiC/SiC. 二m ic lost above 0.2 wt. 15 h and 0 r only 2 h, respectively ation, the weights of SiC/b/SiC lost 0.011 wt% for 10 h. However, The susta indicates that the inter- the weights of SiC/a-BC/SiC lost 0.49 wt% at 700C, 0.011 wt% at face and carbon are damaged by penetration of oxygen 1000C for 100 h. Upon a 1300C oxidation, the weights of Sic an ater. However the f SiC/a-BC/SiC gaineddation, the weights of SiC/B/SiC lost 0.011 wt.% for 10 h. However, the weights of SiC/a-BC/SiC lost 0.49 wt.% at 700 C, 0.011 wt.% at 1000 C for 100 h. Upon a 1300 C oxidation, the weights of SiC/ SiC/SiC, SiC/graphitic B–C/SiC, and SiC/B/SiC lost above 0.2 wt.% for 10 h, 2.5 wt.% for 15 h, and 0.05 wt.% for only 2 h, respectively. The sustained weight loss of the composite indicates that the inter￾face and carbon are damaged by owing to a penetration of oxygen and/or water. However, the weights of SiC/a-BC/SiC gained Fig. 4. Surface morphologies of CVD SiC/a-BC/SiC coatings after oxidized at different temperatures. (a) and (b) at 700 C, (c) and (d) at 1000 C, and (e) and (f) at 1200 C, respectively. Fig. 5. XRD patterns of multilayer SiC/a-BC/SiC coating surface after oxidation. Weight Change (%) Time (h) -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0 10 20 30 40 50 60 70 80 90 100 700 1000 1200 Fig. 6. Weight changes of the coated composites oxidized at different temperatures up to 100 h. Y. Liu et al. / Corrosion Science 51 (2009) 820–826 823