Modeling of forced flow/thermal gradient chemical vapor infiltration

Silicon carbide is a versatile material possessing properties such as a wide energy bandgap, high thermal conductivity, high elastic modulus and high-temperature creep resistance, which enable it to be used in a variety of electronic, optical and structural applications. Chemical vapor infiltration/deposition (CVI/CVD) coupled with the application of a temperature gradient and forced flow of reagents is particularly suited to the production of SiC structural composites due to the benefits of reduced infiltration time and uniform composite density. In this work, the growth and orientation of polycrystalline SiC on graphite during CVI is investigated using TEM and HRTEM.The composites studied possess a laminated matrix of alternating layers of carbon and SiC which were deposited by alternating the reagent streams from one layer to the next. Specimens for TEM examination were obtained by cutting ∽1 mm thickness slices from the bulk sample with a low speed diamond saw.

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

Carbon ◽

10.1016/0008-6223(96)00086-3 ◽

1996 ◽

Vol 34 (9) ◽

pp. 1123-1133 ◽

Cited By ~ 41

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

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Fiber-Reinforced Tubular Composites by Chemical Vapor Infiltration°

MRS Proceedings ◽

10.1557/proc-250-233 ◽

1991 ◽

Vol 250 ◽

Cited By ~ 4

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.

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

MRS Proceedings ◽

10.1557/proc-365-309 ◽

1994 ◽

Vol 365 ◽

Cited By ~ 2

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.

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Carbon/carbon processing by forced flow-thermal gradient chemical vapor infiltration using propylene

Carbon ◽

10.1016/0008-6223(95)00190-5 ◽

1996 ◽

Vol 34 (3) ◽

pp. 347-362 ◽

Cited By ~ 19

Author(s):

Sundar Vaidyaraman ◽

W.Jack Lackey ◽

Pradeep K. Agrawal ◽

Michael A. Miller

Keyword(s):

Thermal Gradient ◽

Chemical Vapor ◽

Chemical Vapor Infiltration ◽

Forced Flow ◽

Carbon Processing ◽

Vapor Infiltration

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

MRS Proceedings ◽

10.1557/proc-365-325 ◽

1994 ◽

Vol 365 ◽

Cited By ~ 2

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.

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