Oxidation-Protection Methodology for Long-Term use of Carbon-Carbon Fiber-Matrix Composites in Oxidizing Ambients

2002 ◽  
Vol 755 ◽  
Author(s):  
Ilan Golecki ◽  
Karen Fuentes ◽  
Terence Walker
Keyword(s):  
Carbon Fiber ◽  
Time Profile ◽  
Matrix Composites ◽  
Weight Changes ◽  
Carbon Foams ◽  
Fiber Matrix ◽  
Sic Composites ◽  
Multi Phase ◽  
Temperature Time

ABSTRACTA methodology is described for protecting Carbon-Carbon fiber-matrix composite (C-C) components from oxidation for extended use in oxidizing ambients for lifetimes of the order of 10,000 hours, from room temperature to 650°C. This time-temperature profile is relevant to applications such as airborne heat exchangers. Weight changes of oxidation-protected, pitch-fiber based C-C coupons in flowing dry air at 650°C are presented. Two types of external protective approaches are compared: (a) multi-phase, borophosphate-based fluidizing overseal coatings applied directly to C-C, and (b) the same overseal coatings applied to CVD SiOxCy coated C-C. The latter, dual-coating approach provides an effective engineering solution for the above temperature-time profile and is particularly applicable to thin (0.1–3 mm thick), complex-shaped articles. The behavior of inert substrates (oxidized silicon) with the same overseal coatings is compared to the behavior of the C-C substrates. This approach can be applied with optional modifications to suit other environmental conditions, and other carbon-containing materials, such as carbon foams and C-SiC composites.

Microstructural Characterization of Carbon Fiber-Reinforced Laminated Matrix Composites of Silicon Carbide and Carbon

1998 ◽  
Vol 4 (S2) ◽  
pp. 568-569
Author(s):  
K. A. Appiah ◽  
Z. L. Wang ◽  
W. J. Lackey
Keyword(s):  
Silicon Carbide ◽  
Carbon Fiber ◽  
Microstructural Characterization ◽  
Bulk Sample ◽  
High Temperature Strength ◽  
Matrix Composites ◽  
Fiber Reinforcements ◽  
Diamond Saw ◽  
Sic Composites ◽  
Processing Effort

Silicon carbide composites are known for high-temperature strength retention, creep resistance, high elastic modulus and light weight. Laminated matrix composites (LMC's) with a matrix of alternating layers of silicon carbide (SiC) and carbon (C) with carbon fiber reinforcements possess added toughness in addition to the desirable properties of SiC composites mentioned above. The improved toughness results from both the laminated matrix, which offers a tortuous path to crack propagation, and the energy expended in fiber debonding during fracture. Microstructural analyses of LMC's are necessary to help the processing effort to achieve structures with the desired properties. In this work, a preliminary examination of the microstructure of the laminated matrix composite is undertaken using TEM.Specimens for TEM examination were prepared by cutting slices from a bulk sample of ∼ 1 mm thickness with a low-speed diamond saw. The slices were then ground to no less than 200 μm thickness to prevent the slices from breaking.

Effect of Silicon Carbide Interlayers on the Mechanical Behavior of T800-HB-Fiber-Reinforced Silicon Carbide-Matrix Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1844-1846 ◽  
Author(s):  
Xin Gui Zhou ◽  
Hai Jiao Yu ◽  
Bo Yun Huang ◽  
Jian Gao Yang ◽  
Ze Lan Huang
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Three Dimensional ◽  
Bending Test ◽  
Matrix Composites ◽  
High Mechanical Strength ◽  
Three Point Bending ◽  
Carbide Matrix ◽  
Fiber Matrix ◽  
Sic Composites

The influence of the fiber/matrix interlayers on the mechanical properties of T800-HB fiber (a kind of carbon fiber) (the fibrous is three-dimensional four-directional braided) reinforced silicon carbide (SiC) matrix composites has been evaluated in this paper. The composites were fabricated through PIP process, and SiC layers were deposited as fiber/matrix interlayers by the isothermal CVD process. Fiber/matrix debonding and relatively long fiber pullouts were observed on the fracture surfaces. The mechanical properties were investigated using three-point bending test and single-edge notched beam test. The T800-HB/SiC composites exhibited high mechanical strength, and the flexural strength and fracture toughness were 511.5MPa and 20.8MPa•m1/2, respectively.

scholarly journals Design, Fabrication, and Testing of Ceramic Joints for High Temperature SiC/SiC Composites

2000 ◽  
Author(s):  
M. Singh ◽  
Edgar Lara-Curzio
Keyword(s):  
Silicon Carbide ◽  
Shear Strength ◽  
Elevated Temperatures ◽  
Stress Rupture ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
Carbide Matrix ◽  
Sic Composites ◽  
Stress Rupture Testing

Various issues associated with the design and mechanical evaluation of joints of ceramic matrix composites are discussed. The specific case of an affordable, robust ceramic joining technology (ARCJoinT) to join silicon carbide (CG-Nicalon™) fiber-reinforced-chemically vapor infiltrated (CVI) silicon carbide matrix composites is addressed. Experimental results are presented for the time and temperature dependence of the shear strength of these joints in air up to 1200°C. From compression testing of double-notched joint specimens with a notch separation of 4 mm, it was found that the apparent shear strength of the joints decreased from 92 MPa at room temperature to 71 MPa at 1200°C. From shear stress-rupture testing in air at 1200°C it was found that the shear strength of the joints decreased rapidly with time from an initial shear strength of 71 MPa to 17.5 MPa after 14.3 hours. The implications of these results in relation to the expected long-term service life of these joints in applications at elevated temperatures are discussed.

Preparation and Properties of 2D Carbon Cloth Reinforced Ultra-High Temperature Ceramic Matrix Composites

2008 ◽  
Vol 368-372 ◽  
pp. 1050-1052 ◽  
Author(s):  
Yong Lian Zhou ◽  
Hai Feng Hu ◽  
Yu Di Zhang ◽  
Qi Kun Wang ◽  
Chang Rui Zhang
Keyword(s):  
High Temperature ◽  
Carbon Fiber ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Carbon Cloth ◽  
Matrix Composites ◽  
Pyrolysis Process ◽  
Sic Composites ◽  
Polymer Infiltration ◽  
Ultra High Temperature

In this paper the preparation of carbon fiber reinforced ultra-high temperature ceramic matrix composites was reported. Polymer infiltration and pyrolysis process was used to prepare 2D C/TaC-SiC, C/NbC-SiC, and C/ZrC-SiC composites. The fracture strengths of all the samples were around 300MPa and toughness around 10MPa-m1/2. Standard oxyacetylene torch tests (>3000°C, 30s) showed that the minimum ablative rate of 2D C/SiC-ZrC was as low as 0.026 mm/s, much smaller than that of 2D C/SiC composites (0.088mm/s).

Carbon Fiber Reinforced SiC Matrix Composites Fabricated by Preceramic Impregnation and Pyrolysis Process Combining SiC Nano Powder Infiltration

2014 ◽  
Vol 1052 ◽  
pp. 34-39 ◽  
Author(s):  
Jing Jing Wang ◽  
Wen Song Lin ◽  
Li Hui Duan ◽  
Xue Zeng Yan
Keyword(s):  
Carbon Fiber ◽  
Three Dimensional ◽  
Ceramic Matrix Composites ◽  
Matrix Composites ◽  
Low Viscosity ◽  
Nano Powder ◽  
Sic Particles ◽  
Sic Composites ◽  
20 Nm ◽  
Polymer Impregnation

SiC nanopowder, polycarbosilane and divinylbenzene mixed slurries were prepared for viscosity measurement, which were used as matrix source of ceramic matrix composites. Results showed that apparent viscosity of the slurries increased with the increase of the content of SiC particles. The slurries with 50 nm SiC particles showed a low viscosity as compared with those slurries with 20 nm or 120 nm SiC particles at the same content of SiC. In particular, when the viscosity of slurry was higher than 30 mPa•s, the slurry could not be used in the test. Three-dimensional carbon fiber (3D-Cf) preforms were infiltrated with the aforementioned slurries. Addition of the nanoSiC powder as the inert filler in the slurries led to reduce the porosity and the infiltration–curing–pyrolysis cycles to manufacture 3D-Cf/SiC composites by the subsequent polymer impregnation and pyrolysis (PIP) process. Characterizations of the composites showed that the maximum flexural strength of specimen in the composites was 326 MPa and its fracture toughness was 10.5 MPa•m1/2.

Fabrication and Characteristics of Carbon Fiber Reinforced C–SiC Dual Matrix Composites

2007 ◽  
Vol 334-335 ◽  
pp. 145-148 ◽  
Author(s):  
Dong Mei Zhu ◽  
Fa Luo ◽  
Hong Na Du ◽  
Wan Cheng Zhou
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Matrix Composites ◽  
Fiber Reinforced ◽  
Final Density ◽  
Carbon Fiber Reinforced ◽  
Sic Composites ◽  
Xylene Solution

A series of carbon fiber reinforced C-SiC dual matrix composites (C/C-SiC composites) were developed through precursor infiltration of polycarbosilane (PCS) and pyrolysis (PIP), using porous C/C composites with different density from chemical vapor infiltration (CVI) as the preform. The density, mechanical properties, and microstructure of the composites were investigated and the effects of the preform density and the PCS concentration of the infiltration solution on the final density and the mechanical properties of the composites were discussed in detail. The results show that the final density of the C/C-SiC composites prepared at the infiltration concentration of 50% is the highest, indicating that 50% is the proper PCS concentration of the PCS/ Xylene solution to prepare the C/C-SiC composites. The final densities of C/C-SiC composites were closely related to the preform density and the highest final density corresponds to the highest original preform density. For the composites prepared using infiltration solution of 50% PCS, the C/C-SiC composite whose preform density is 1.23 g/cm3 possesses the best mechanical properties while that whose preform density is 1.49 g/cm3 the worst mechanical properties.

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