1-D model for forced flow-thermal gradient chemical vapor infiltration process for carbon/carbon composites

Carbon ◽  
1996 ◽  
Vol 34 (9) ◽  
pp. 1123-1133 ◽  
Author(s):  
S. Vaidyaraman ◽  
W.J. Lackey ◽  
P.K. Agrawal ◽  
T.L. Starr
1991 ◽  
Vol 250 ◽  
Author(s):  
D. P. Stinton ◽  
R. A. Lowden ◽  
T. M. Besmann

AbstractA forced-flow thermal-gradient chemical vapor infiltration process has been developed to fabricate composites of thick-walled tubular geometry common to many components. Fibrous preforms of different fiber architectures (3-dimensionally braided and filament wound) have been investigated to accommodate components with different mechanical property requirements. This paper will discuss the fabrication of tubular, fiber-reinforced SiC matrix composites and their mechanical properties.


1994 ◽  
Vol 365 ◽  
Author(s):  
W.M. Matlin ◽  
D.P. Stinton ◽  
T.M. Besmann ◽  
P.K. Liaw

ABSTRACTA two-step forced-flow, thermal-gradient, chemical vapor infiltration process (FCVI) was proposed to reduced processing time while maintaining uniformly high densities. GTCVI, a finite-volume computer code developed specifically for the FCVI process was used to model thermal gradient effects on processing time and density. An optimum thermal gradient was determined and used to process material with uniformly infiltrated bundles.


1995 ◽  
Vol 10 (6) ◽  
pp. 1469-1477 ◽  
Author(s):  
Sundar Vaidyaraman ◽  
W. Jack Lackey ◽  
Garth B. Freeman ◽  
Pradeep K. Agrawal ◽  
Matthew D. Langman

Carbon fiber-carbon matrix composites were fabricated using the forced flow-thermal gradient chemical vapor infiltration (FCVI) process. The preforms for the infiltration were prepared by stacking 40 layers of carbon cloth in a graphite holder. The preforms were infiltrated with carbon using propylene or methane as a reactant, with hydrogen as a diluent. Composites with porosities as low as 7% have been processed within 8-12 h. The highest deposition rate obtained in the present study was ∼3 μm/h, which is more than an order of magnitude faster than the typical value of 0.1-0.25 μm/h for the isothermal infiltration process.


Carbon ◽  
1995 ◽  
Vol 33 (9) ◽  
pp. 1211-1215 ◽  
Author(s):  
Sundar Vaidyaraman ◽  
W.Jack Lackey ◽  
Pradeep K. Agrawal ◽  
Garth B. Freeman

1991 ◽  
Vol 250 ◽  
Author(s):  
Ching-Yi Tsai ◽  
Seshu B. Desu

AbstractA model, incorporating both gas-phase and surface reactions, for simulating thickness profile of SiC, deposited from trichloromethylsilane (TMS), along the longitudinal direction of a single pore is presented in this paper. The transport mechanisms considered include both forced-flow and diffusion. With the nonlinear nature of this model, a finite element model was developed to solve the problem numerically. Simulation results were in good agreement with the reported experimental data by Fedou et al. (1990). Effects of critical parameters, such as deposition temperature, ratio of sticking coefficients of TMS and intermediate species, and forced-flow, on the deposition thickness profile were investigated. Forced-flow effect was found to be small for the chemical vapor infiltration (CVI) processes at high deposition temperatures.


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