Carbon‐Fiber‐Reinforced Composites with Graded Carbon‐Silicon Carbide Matrix Composition

Abstract

Carbon-silicon carbide (C-SiC) graded-matrix composites were prepared via chemical vapor infiltration with carbon and SiC codeposition from methyltrichlorosilane (CH 3 SiCl 3 ), acetylene (C 2 H 2 ), argon, and hydrogen. The graded-matrix composites were prepared by gradually varying the source gases, from C 2 H 2 to CH 3 SiCl 3 , in a semicontinuous process. Oxidation resistance, wear, and mechanical tests were conducted, and the microstructure was observed via optical microscopy, electron probe microanalysis, transmission electron microscopy, and scanning electron microscopy. The results show that this material seems to be macroscopically homogeneous, as an integral part of the entire material; however, microscopic examination shows a gradient variation of the matrix sheaths around each fiber. The oxidation resistance of the material is significantly superior to that of a C/C material, which is a promising thermostructural material, because of its low density, good mechanical properties, and good resistance to oxidation.

Processing of Non-Oxide Ceramic Matrix Composites: An Overview

“…at low T, P, a large number of fiber preforms (preferably self-standing) with different sizes and shapes, can be treated simultaneously in huge deposition chambers, with limited manpower and under very clean conditions [27]. Further, the deposited matrix can be either single phase (PyC in C/C composites or stoichiometric SiC in C/SiC and SiC/SiC composites) or consisting of several phases with graded [28] or multilayered [29,30] microstructures. A representative example, of that composition flexibility is the so-called self-healing multilayered matrices, (MLSH) (X-Y-X-Y') n , with improved oxidation resistance, where X is a layer of mechanical fuse for crack deflection (PyC or BN) and Y, Y' layers of materials forming protective (fluid) oxides (silica or/and boria) in oxidizing atmospheres, such as B 4 C, SiC, SiB 6 , Si-B-C, healing matrix cracks (far from the fiber surface) as soon as they form under load [29,31].…”

Preparation and properties of C/C–SiC nano-composites

“…4 Another useful method is CVI, in which the composite material is prepared by changing the matrix from C in the core to SiC on the surface by changing the precursors that determine the C-to-SiC ratio. 5 Other methods for the preparation of C/SiC composites mainly involve the use of organometallic precursors that form SiC during the pyrolysis and are used for the impregnation of carbon fibres or fabrics during the preparation of the composite. The latest generation of polymeric precursors are used for the impregnation of carbon fibres or fabrics and after pyrolysis form SiC with an efficiency of around 75-85 wt.%.…”

“…During pyrolysis the SiO 2 reacts with carbon, and SiC is formed. [5][6][7][8][9][10][11] These precursors are much cheaper but the stoichiometry of the SiC formed depends on the ratio of the SiO 2 and carbon formed during the pyrolysis. The difference is also in the temperature of the pyrolysis, which in this case has to be higher than 1000 • C.…”

Influence of Features of Silicon Carbide Ceramic Matrix Composite (C_p/SiC) on Carbon Content

“…So carbon fiber reinforced silicon carbide ceramic composites(C f /SiC) of different types was prepared. Lots of conferences show that C f /SiC have many excellent properties such as high temperature resistance, high thermal shock resistance, high thermal conductivity [3][4][5][6] . Therefore, it was applicated to Optical systems, Space technology, inflamer, re-entry shields, rocket nozzles, disc-brakes and prosthetic devices and so on [7][8] .…”