The Role of Gas‐Phase Reactions in Modeling of the Forced‐Flow Chemical Vapor Infiltration Process

1993 ◽  
Vol 140 (7) ◽  
pp. 2121-2124 ◽  
Author(s):  
Ching Yi Tsai ◽  
Seshu B. Desu ◽  
Chien C. Chiu ◽  
J. N. Reddy
Keyword(s):  
Gas Phase ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Gas Phase Reactions ◽  
Infiltration Process ◽  
Vapor Infiltration

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.

Advances in Modeling of the Chemical Vapor Infiltration Process

1991 ◽  
Vol 250 ◽  
Author(s):  
Thomas L. Starr
Keyword(s):  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Forced Flow ◽  
Material Transport ◽  
Process Technology ◽  
Infiltration Process ◽  
Design And Manufacture ◽  
Vapor Infiltration

AbstractThe technology of chemical vapor infiltration (CVI) has progressed dramatically over the past twenty-five years and stands now as the leading process for fabrication of high temperature structures using ceramic matrix composites. Modeling techniques also have advanced from extensions of catalyst theory to full 3-D finite element code with provision for temperature and pressure gradients. These modeling efforts offer insight into critical factors in the CVI process, suggest opportunities for further advances in process technology and provide a tool for integrating the design and manufacture of advanced components.Early modeling identified the competition between reaction and diffusion in the CVI process and the resulting trade-off between densification rate and uniformity. Modeling of forced flow/thermal gradient CVI showed how the evolution of material transport properties provides a self-optimizing feature to this process variation.“What-if” exercises with CVI models point toward potential improvements from tailoring of the precursor chemistry and development of special preform architectures.As a link between component design and manufacture, CVI modeling can accelerate successful application of ceramic composites to advanced aerospace and energy components.

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.

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.

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.

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