scholarly journals Forced Chemical Vapor Infiltration of Tubular Geometries: Modeling, Design, and Scale-Up

1994 ◽  
Vol 365 ◽  
Author(s):  
D.P. Stinton ◽  
T.M. Besmann ◽  
W.M. Matlin ◽  
T.L. Starr ◽  
W.A. Curtain
Keyword(s):  
Mechanical Properties ◽  
Processing Time ◽  
Scale Up ◽  
Chemical Vapor ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Outer Diameter ◽  
Densification Process ◽  
Vapor Infiltration

ABSTRACTThe development of thick-walled, tubular ceramic composites has involved investigations of different fiber architectures and fixturing to obtain optimal densification and mechanical properties. The current efforts entail modeling of the densification process in order to increase densification uniformity and decrease processing time. In addition, the process is being scaled to produce components with a 10 cm outer diameter.

scholarly journals Chemical Vapor Infiltration Process Modeling and Optimization

1995 ◽  
Vol 410 ◽  
Author(s):  
T. M. Besmann ◽  
W. M. Matlin ◽  
D. P. Stinton
Keyword(s):  
Process Modeling ◽  
Scale Up ◽  
Chemical Vapor ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Chemical Degradation ◽  
Continuous Fiber ◽  
Infiltration Process ◽  
Unique Method ◽  
Vapor Infiltration

ABSTRACTChemical vapor infiltration is a unique method for preparing continuous fiber ceramic composites that spares the strong but relatively fragile fibers from damaging thermal, mechanical, and chemical degradation. The process is relatively complex and modeling requires detailed phenomenological knowledge of the chemical kinetics and mass and heat transport. An overview of some of the current understanding and modeling of CVI and examples of efforts to optimize the processes is given. Finally, recent efforts to scale-up the process to produce tubular forms are described.

scholarly journals Microstructural Regulation, Oxidation Resistance and Mechanical Properties of Cf/SiC/SiHfBOC Composites Prepared By Chemical Vapor Infiltration With Precursor Infiltration Pyrolysis

2021 ◽  
Author(s):  
Yang LYU ◽  
Baihe DU ◽  
Guiqing CHEN ◽  
Guangdong ZHAO ◽  
Yuan CHENG ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxidation Resistance ◽  
Microscopic Analysis ◽  
Chemical Vapor ◽  
Ceramic Composites ◽  
Chemical Vapor Infiltration ◽  
Weight Retention ◽  
Composite Surface ◽  
Before And After ◽  
Vapor Infiltration

Abstract To further improve the oxidation resistance of PDC (Polymer Derived Ceramic) composites in harsh environments, Cf/SiC/SiHfBOC composites were prepared by CVI (Chemical Vapor Infiltration) and PIP (Precursor Impregnation Pyrolysis) methods. The weight retention change, mechanical properties, and microstructure of Cf/SiC/SiHfBOC before and after oxidation in air were studied in detail. Microscopic analysis showed that only the interface between the ceramic and fibers were oxidized to some extent and hafnium had been enriched on the composite surface, after oxidation at different oxidation environments. After Cf/SiC/SiHfBOC composites oxidized at 1500 ℃ for 60 min, it was mainly determined by the HfO2 and HfSiO4 phase. Moreover, the weight retention ratio and compressive strength of the Cf/SiC/SiHfBOC composites are 83.97 % and 23.88 ± 3.11 MPa, respectively. It indicates that the Cf/SiC/SiHfBOC composites can be used for a long time in the oxidation environment at 1500 ℃.

Effects of chemical vapor infiltration atmosphere on the mechanical properties and microstructure of carbon fibers

2001 ◽  
Vol 21 (6) ◽  
pp. 809-816 ◽  
Author(s):  
Yongdong Xu ◽  
Laifei Cheng ◽  
Litong Zhang ◽  
Hongfeng Yin ◽  
Xiaowei Yin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Fibers ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Vapor Infiltration

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.

Chemical vapor infiltration of SiC with microwave heating

1993 ◽  
Vol 8 (5) ◽  
pp. 1057-1067 ◽  
Author(s):  
José I. Morell ◽  
Demetre J. Economou ◽  
Neal R. Amundson
Keyword(s):  
Microwave Heating ◽  
Processing Time ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Chemical System ◽  
Gaseous Species ◽  
Composite Surface ◽  
Transport Reaction ◽  
Accessible Porosity ◽  
Vapor Infiltration

A mathematical model was developed to elucidate the interaction between transport/reaction processes and the evolution of porosity in chemical vapor infiltration with microwave heating (MCVI). The analysis included a set of partial differential equations describing the spatiotemporal variation of gaseous species concentration, composite temperature, porosity, and stress. Maxwell's equations were used to determine the distribution of power dissipated inside the composite. The deposition of silicon carbide was selected as a model chemical system to explore the general features of MCVI. MCVI can provide a favorable temperature distribution in the composite yielding an inside-out deposition pattern, thereby preventing entrapment of accessible porosity. For this temperature profile, tensile stresses develop at the outer regions and compressive stresses are found in the composite core. For a given system there exists a minimum value of the coefficient for heat transfer from the composite surface, h, below which accessible porosity is trapped within the composite. Similarly, there exists a maximum value of the incident microwave energy flux, I0, above which accessible porosity is trapped within the composite. I0 and h can be optimized for a given preform to achieve complete densification with minimum processing time. Using the technique of pulsed-power, the processing time can be reduced even further without compromising density uniformity. Power dissipation profiles in the composite depend strongly on preform thickness, microwave frequency, and relative loss factor.

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