Fabrication of carbon-carbon composites by forced flow-thermal gradient chemical vapor infiltration

1995 ◽  
Vol 10 (6) ◽  
pp. 1469-1477 ◽  
Author(s):  
Sundar Vaidyaraman ◽  
W. Jack Lackey ◽  
Garth B. Freeman ◽  
Pradeep K. Agrawal ◽  
Matthew D. Langman
Keyword(s):  
Thermal Gradient ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Carbon Cloth ◽  
Matrix Composites ◽  
Infiltration Process ◽  
Order Of Magnitude ◽  
Vapor Infiltration

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.

Rapid Processing of Carbon-Carbon Composites by Forced Flow-Thermal Gradient Chemical Vapor Infiltration (FCVI)

1994 ◽  
Vol 365 ◽  
Author(s):  
S. Vaidyaraman ◽  
W. J. Lackey ◽  
P. K. Agrawal ◽  
G. B. Freeman ◽  
M. D. Langman
Keyword(s):  
Thermal Gradient ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Carbon Cloth ◽  
Matrix Composites ◽  
Order Of Magnitude ◽  
Rapid Processing ◽  
Vapor Infiltration

ABSTRACTCarbon fiber-carbon matrix composites were fabricated using the forced flow-thermal gradient chemical vapor infiltration (FCVI) process. Preforms were prepared by stacking 40 layers of plain weave carbon cloth in a graphite holder. The preforms were infiltrated using propylene, propane, and methane. The present work showed that the FCVI process is well suited for fabricating carboncarbon composites; without optimization of the process, we have achieved uniform and thorough densification. Composites with porosities as low as 7% were fabricated in 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 process. It was also found that the use of propylene and propane as reagents resulted in faster infiltration compared to methane.

Fiber-Reinforced Tubular Composites by Chemical Vapor Infiltration°

1991 ◽  
Vol 250 ◽  
Author(s):  
D. P. Stinton ◽  
R. A. Lowden ◽  
T. M. Besmann
Keyword(s):  
Mechanical Properties ◽  
Thermal Gradient ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Infiltration Process ◽  
Filament Wound ◽  
Vapor Infiltration

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.

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
Keyword(s):  
Thermal Gradient ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Carbon Composites ◽  
Infiltration Process ◽  
D Model ◽  
Vapor Infiltration

Optimization of Bundle Infiltration in the Forced Chemical Vapor Infiltration (FCVI) Process

1994 ◽  
Vol 365 ◽  
Author(s):  
W.M. Matlin ◽  
D.P. Stinton ◽  
T.M. Besmann ◽  
P.K. Liaw
Keyword(s):  
Thermal Gradient ◽  
Processing Time ◽  
Chemical Vapor ◽  
Computer Code ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Infiltration Process ◽  
Gradient Effects ◽  
Process Material ◽  
Vapor Infiltration

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.

Forced flow-thermal gradient chemical vapor infiltration (FCVI) for fabrication of carbon/ carbon

Carbon ◽  
1995 ◽  
Vol 33 (9) ◽  
pp. 1211-1215 ◽  
Author(s):  
Sundar Vaidyaraman ◽  
W.Jack Lackey ◽  
Pradeep K. Agrawal ◽  
Garth B. Freeman
Keyword(s):  
Thermal Gradient ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Vapor Infiltration

A model for front evolution with a nonlocal growth rate

1999 ◽  
Vol 14 (10) ◽  
pp. 3829-3832 ◽  
Author(s):  
Shi Jin ◽  
Xuelei Wang ◽  
Thomas L. Starr
Keyword(s):  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Front Propagation ◽  
Chemical Vapor Infiltration ◽  
Matrix Composites ◽  
Infiltration Process ◽  
Physical Problems ◽  
Eulerian Formulation ◽  
Continuous Filament ◽  
Vapor Infiltration

In this paper we provide a new mathematical model for front propagation with a nonlocal growth law in any space dimension. Such a problem arises in composite fabrication using the vapor infiltration process and in other physical problems involving transport and reaction. Our model, based on the level set equation coupled with a boundary value problem of the Laplace equation, is an Eulerian formulation, which allows robust treatment for topological changes such as merging and formation of pores without artificially tracking them. When applied to the fabrication of continuous filament ceramic matrix composites using chemical vapor infiltration, this model accurately predicts not only residual porosity but also the precise locations and shapes of all pores.

Contribution of Gas-Phase Reactions to the Deposition of SiC by A Forced-Flow Chemical Vapor Infiltration Process

1991 ◽  
Vol 250 ◽  
Author(s):  
Ching-Yi Tsai ◽  
Seshu B. Desu
Keyword(s):  
Gas Phase ◽  
Chemical Vapor ◽  
Longitudinal Direction ◽  
Element Model ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Critical Parameters ◽  
Infiltration Process ◽  
Thickness Profile ◽  
Vapor Infiltration

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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