scholarly journals Chemical Vapor Infiltration of Non-Oxide Ceramic Matrix Composites

1993 ◽  
Vol 327 ◽  
Author(s):  
Theodore M. Besmann ◽  
David P. Stinton ◽  
Richard A. Lowden
Keyword(s):  
State Of The Art ◽  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Oxide Ceramic ◽  
Matrix Composites ◽  
Aerospace Applications ◽  
Structural Applications ◽  
Vapor Infiltration

AbstractContinuous fiber ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being investigated, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide-based materials are, by far, the most mature, and are already being used in aerospace applications. This paper addresses the state-of-the art of the technology and outlines current issues.

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.

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.

scholarly journals Microwave Assisted Chemical Vapor Infiltration

1991 ◽  
Vol 250 ◽  
Author(s):  
D. J. Devlin ◽  
R. P. Currier ◽  
R. S. Barbero ◽  
B. F. Espinoza ◽  
N. Elliott
Keyword(s):  
Chemical Vapor ◽  
Ceramic Matrix Composites ◽  
Chemical Vapor Infiltration ◽  
Thermal Gradients ◽  
Matrix Composites ◽  
Microwave Assisted ◽  
Processing Times ◽  
Optical Thermometry ◽  
Complex Shapes ◽  
Vapor Infiltration

AbstractA microwave assisted process for production of continuous fiber reinforced ceramic matrix composites is described. A simple apparatus combining a chemical vapor infiltration reactor with a conventional 700 W multimode oven is described. Microwave induced inverted thermal gradients are exploited with the ultimate goal of reducing processing times on complex shapes. Thermal gradients in stacks of SiC (Nicalon) cloths have been measured using optical thermometry. Initial results on the “inside out” deposition of SiC via decomposition of methyltrichlorosilane in hydrogen are presented. Several key processing issues are identified and discussed.

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