Fabrication of SiC fiber reinforced SiC composite by chemical vapor infiltration for excellent mechanical properties

Igawa, Naoki; Taguchi, Tomitsugu; Nozawa, Takashi; Snead, Lance Lewis; Hinoki, Tatsuya; McLaughlin, J.C.; Katoh, Yutai; Jitsukawa, Shiro; Kohyama, Akira

doi:10.1016/j.jpcs.2004.06.030

Cited by 50 publications

(26 citation statements)

References 8 publications

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“…As thermal protection concepts for superalloy components used in the most advanced gas turbine engines reach their high-temperature limits, interest has grown in the development of components made from ceramic materials with much higher maximum use temperatures [1][2][3][4][5]. The focus has concentrated upon damage-tolerant fiber-reinforced ceramic matrix composites (CMCs) with weak fiber/matrix interfaces.…”

Section: Introductionmentioning

confidence: 99%

“…Unfortunately, these normally protective SiO 2 scales react with water vapor at high temperatures and pressures typical of the gas turbine combustion environment, to form gaseous silicon hydroxide (Si(OH) 4 ) resulting in recession of the SiC [10][11][12][13][14][15]. The rate of SiC volatilization by these mechanisms depends upon the temperature, the incident water vapor flux (pressure), and the effectiveness with which the silicon hydroxide reaction products can be removed.…”

Section: Introductionmentioning

confidence: 99%

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Structure, composition, and defect control during plasma spray deposition of ytterbium silicate coatings

2015

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Environmental barrier coatings (EBCs) are needed to protect SiC structures exposed to high temperatures in water vapor-rich environments. Recent studies of a tri-layer EBC system consisting of a silicon layer attached to the SiC, a mullite diffusion barrier and a lowsteam volatility ytterbium silicate topcoat have shown some promise for use at temperatures up to 1316°C. However, the performance of the coating system appeared to be dependent upon the manner of its deposition. Here, an air plasma spray method has been used to deposit this trilayer EBC on a-SiC substrates, and the effects of the plasma arc current and hydrogen content upon the structure, composition, and defects in ytterbium monosilicate (Yb 2 SiO 5 ) and disilicate (Yb 2 Si 2 O 7 ) topcoats are investigated. Modification of spray parameters enabled the loss of SiO from the injected powder to be reduced, leading to partial control of coating stoichiometry and phase content. It also enabled significant control of the morphology of solidified droplets, the porosity, and the microcracking behavior within the coatings. Differences between the Yb 2 SiO 5 and Yb 2 Si 2 O 7 are discussed in the context of their EBC application.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure, composition, and defect control during plasma spray deposition of ytterbium silicate coatings

2015

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“…1). State of the art in SiC/SiC composites has solved most of the potential issues of near-net shaping and machining, joining technology and evaluation technology [68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86]. There are no doubts that SiC/SiC composites are at the forefront of advanced materials technology and prime candidates for structural material in severe environments.…”

Section: Introductionmentioning

confidence: 99%

Erosive Wear Mechanism of New SiC/SiC Composites by Solid Particles

Suh

Hinoki

2010

Tribol Lett

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A solid-particle erosive wear test by impinging silicon carbide (SiC) powders was carried out at room temperature over a range of median particle sizes of 425-600 lm, speed of 100 m/s and impact angle of 90°a nd assessed by wear measurements and scanning electron microscopy. Erosive wear behaviour was examined on newly fabricated nano-powder infiltration and transient eutectoid (NITE) SiC/SiC composites and two commercial composites by the chemical vapour infiltration (CVI) and NITE fabrication route. Microstructural observation was performed to examine the correlation between erosive wear behaviours and fabrication impurities. Conspicuous defects were observed in the prototype materials as the forms of porosity, fibre deformation, residual oxide, pyrolytic carbon (PyC) deformation, PyC cleavage, among others. Erosive wear behaviour was rather serious in the prototype of fabricated composites, which employ pre-SiC fibre and phenolic resin. Two dominant erosive wear mechanisms were observed: delamination of constituents, mainly caused by erosive crack propagation, and fragmentation and detachment of constituents, which usually resulted from erosive impact. A unit size of delamination was the most decisive factor affecting wear volume. The bonding strength of each constituent was mostly affected by various forms of porosities. Therefore, the fundamental cause and subsequent results must be carefully elucidated. The correlation of microstructural defect and wear behaviour was investigated with the aim of reducing dominant wear by improving fabrication conditions. The final product of the cost-effective composite had a 2.5-fold higher resistance than the commercial CVI composite. Consequently, by controlling fabrication impurities, we have been successful in developing and improving a new fabrication technique; consequently, the known defects are rarely observed in final product. A schematic wear model of erosive wear mechanisms is proposed for the newly fabricated SiC/SiC composites under particle erosion.

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“…Several processes are still under consideration to deposit the SiC matrix within the woven fibrous preform (Naslain, 2004) and improve the thermo-mechanical behavior of the composite. Yet, the Chemical Vapor Infiltration (CVI) is promising since it produces a highly pure and near-stoichiometric b-SiC matrix (Deck et al, 2012;Igawa et al, 2005), which is required to limit degradation under radiation. Nevertheless, this process does not allow a perfect infiltration of the composite and leads to an inter-and intra-tow residual porosity.…”

Section: Introductionmentioning

confidence: 99%

Micromechanical modeling of the elastic behavior of unidirectional CVI SiC/SiC composites

Chateau

Gélebart

Bornert

et al. 2015

International Journal of Solids and Structures

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International audienceThe elastic behavior of SiC/SiC composite is investigated at the scale of the tow through a micromechanical modeling taking into account the heterogeneous nature of the microstructure. The paper focuses on the sensitivity of transverse properties to the residual porosity resulting from the matrix infiltration process. The full analysis is presented stepwise, starting from the microstructural characterization to the study of the impact of pore shape and volume fraction. Various Volume Elements (VEs) of a virtual microstructure are randomly generated. Their microstructural properties are validated with respect to an experimental characterization based on high definition SEM observations of real materials, using various statistical descriptors. The linear elastic homogenization is performed using finite elements calculations for several VE sizes and boundary conditions. Important fluctuations of the apparent behavior, even for large VEs, reveal that scales are not separated. Nevertheless, a homogeneous equivalent behavior is estimated by averaging apparent behaviors of several VEs smaller than the Representative Volume Element (RVE). Therefore, the impact of the irregular shape of the pores on the overall properties is highlighted by comparison to a simpler cylindrical porous microstructure. Finally, different matrix infiltration qualities are simulated by several matrix thicknesses. A small increase in porosity volume fraction is shown to potentially lead to an important fall of transverse elastic moduli together with high stress concentrations

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Fabrication of SiC fiber reinforced SiC composite by chemical vapor infiltration for excellent mechanical properties

Cited by 50 publications

References 8 publications

Structure, composition, and defect control during plasma spray deposition of ytterbium silicate coatings

Structure, composition, and defect control during plasma spray deposition of ytterbium silicate coatings

Erosive Wear Mechanism of New SiC/SiC Composites by Solid Particles

Micromechanical modeling of the elastic behavior of unidirectional CVI SiC/SiC composites

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