Chemical Vapor Infiltration of Carbon Fiber Felts from Methane: Influence of Surface Area / Volume Ratios

2006 ◽  
pp. 107-114
Author(s):  
W.G. Zhang ◽  
Y.P. Zhu ◽  
K.J. Hüttinger
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Vapor Infiltration

Chemical Vapor Infiltration of Carbon Fiber Felts from Methane: Influence of Surface Area / Volume Ratios

2006 ◽  
Vol 50 ◽  
pp. 107-114 ◽  
Author(s):  
W.G. Zhang ◽  
Yong Ping Zhu ◽  
K.J. Hüttinger
Keyword(s):  
Carbon Fiber ◽  
Surface Area ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Polarized Light ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Initial Surface ◽  
Fiber Volume ◽  
Vapor Infiltration

Isothermal, isobaric chemical vapor infiltration of carbon fiber felts with fiber volume fractions of 7.1% and 14.2% were investigated at infiltration times from 20 to 120 hours, using a constant temperature of 1095 oC and a methane pressure of 22.5 kPa. Bulk densities and the density profiles as well as porosity at various densification stages were determined. Inside–outside densification was obtained in the most infiltrations, the gradients of densification along the infiltration depth decrease with increasing of residence time and infiltration times. Outside–inside densification occurs only in the felt with the lower fiber volume fraction at final infiltration stage and at longer residence times. Microstructure of the obtained matrix carbon was analyzed with a polarized light microscopy. Abruptly change from low/medium textured carbon to medium/high textured carbon are observed in both of the carbon fiber felts, whereas the thickness of the first lower textured layer is about 14 micros in the felt with a fiber volume fraction of 7.1%, whereas it is only 2 micros in the felt with a fiber volume fraction of 14.2%, which is caused by an increasing of initial surface area / volume ratio, [A/V], from 33 to 71 mm-1. Results are completely in agreement with the previous simulations studies on the influence of [A/V] ratios.

Microstructure and Mechanical Property of 3D Textile C/SiC Composites Fabricated by Chemical Vapor Infiltration

2006 ◽  
Vol 11-12 ◽  
pp. 81-84 ◽  
Author(s):  
Dong Lin Zhao ◽  
Hong Feng Yin ◽  
Fa Luo ◽  
Wan Cheng Zhou
Keyword(s):  
Mechanical Property ◽  
Silicon Carbide ◽  
Carbon Fiber ◽  
Interfacial Layer ◽  
Chemical Vapor ◽  
Pyrolytic Carbon ◽  
Chemical Vapor Infiltration ◽  
Sic Composites ◽  
Microstructure And Mechanical Property ◽  
Vapor Infiltration

Three dimensional textile carbon fiber reinforced silicon carbide (3D textile C/SiC) composites with pyrolytic carbon interfacial layer were fabricated by chemical vapor infiltration. The microstructure and mechanical property of 3D textile C/SiC composites were investigated. A thin pyrolysis carbon layer (0.2 ± μm) was firstly deposited on the surface of carbon fiber as the interfacial layer with C3H6 at 850°C and 0.1 MPa. Methyltrichlorosilane (CH3SiCl3 or MTS) was used for the deposition of the silicon carbide matrix. The conditions used for SiC deposition were 1100°C, a hydrogen to MTS ratio of 10 and a pressure of 0.1 MPa. The density of the composites was 2.1 g cm-3. The flexural strength of the 3D textile C/SiC composites was 438 MPa. The 3D textile C/SiC composites with pyrolytic carbon interfacial layer exhibit good mechanical properties and a typical failure behavior involving fibers pull-out and brittle fracture of sub-bundle. The real part (ε′) and imaginary part (ε″) of the complex permittivity of the 3D-C/SiC composites are 51.53-52.44 and 41.18-42.08 respectively in the frequency range from 8.2 to 12.4 GHz. The 3D-C/SiC composites would be a good candidate for microwave absorber.

Improvement of the strength and toughness of carbon fiber/SiC composites via chemical vapor infiltration-grown SiC nanowire interphases

2018 ◽  
Vol 44 (2) ◽  
pp. 2311-2319 ◽  
Author(s):  
Fang He ◽  
Yongsheng Liu ◽  
Zhuo Tian ◽  
Chengyu Zhang ◽  
Fang Ye ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Sic Composites ◽  
Strength And Toughness ◽  
Vapor Infiltration
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