Fiber-Reinforced Tubular Composites by Chemical Vapor Infiltration°

Stinton, D.P.; Lowden, R.A.; Besmann, Theodore M.

doi:10.1557/proc-250-233

Cited by 13 publications

(19 citation statements)

References 11 publications

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“…The obtained results demonstrate that SLs facilitate the development of new CVD processes with superior conformality onto high-AR 3D features. To achieve even higher conformality, SLs can be combined with other strategies for conformal CVDs ,,,− ,− including utilization of surface inhibitors − and quasi zeroth-order reaction kinetics, , which are summarized in Table . Furthermore, the use of SLs is not limited to CVD; it can also be applied to other deposition techniques (e.g., ALD) involving multiple film-forming species where η values vary by several orders of magnitude.…”

Section: Resultsmentioning

confidence: 99%

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Shima

Funato

Satô

et al. 2020

ACS Appl. Mater. Interfaces

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We propose a new, concise method for conformal chemical vapor deposition (CVD) using sacrificial layers (SLs) to fill three-dimensional features with microscopic pores. SLs are porous membranes (e.g., ceramic felts) that filter film-forming species having high sticking-probability (η). CVD processes with multiple film-forming species generally suffer from poor conformality due to preferential film deposition at the inlets of features by the high-η species, such as reactive intermediates. An SL traps such high-η species before they reach the target features and selectively supplies film-forming species with lower η (e.g., source precursors or stable intermediates) that enables conformal film deposition. Here the trapping efficiency of an SL was predicted and a procedure for designing an optimal SL was established. The procedure was demonstrated by CVD of silicon carbide (SiC) with multiple film-forming species of high-η species (η = 8.0 × 10–3) and lower-η species (η = 5.9 × 10–5 and 2.2 × 10–7). The trapping of 99.2% of incident high-η species was achieved with an optimized SL, wherein the deposition rate (m/s) contribution by high-η species declined from 0.546 at the SL inlet to 0.014 at its outlet. Finally, using these optimized SLs, SiC-CVD filling of micron-scale trenches was demonstrated with an aspect-ratio of 16:1.

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Section: Resultsmentioning

confidence: 99%

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Shima

Funato

Satô

et al. 2020

ACS Appl. Mater. Interfaces

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“…Gupta and Evans modeled the infiltration of SiC at microwave frequencies and showed the existence of "inverted" thermal gradients which could be exploited for CVI. 1 ' Morell et al modeled the infiltration of carbon preforms by representing volumetric heating as a constant heat source term in the energy balance. 1 " 2 .…”

Section: Introductionmentioning

confidence: 99%

“…In a later study on the infiltration of SiC with microwave heating, Morell et al accounted for the variation of power across the thickness of the preform by solving Maxwell's equations for the electric field. 1 3 Although D models are adequate for a preliminary evaluation of the process, 2D models are necessary to account for the finite geometry of the preform. Important approximations in the physical description of the process introduced by D models can be eliminated by 2D models.…”

Section: Introductionmentioning

confidence: 99%

A Two‐Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

Midha

Economou

1997

J. Electrochem. Soc.

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A comprehensive, two-dimensional, self-consistent model was developed and used to simulate chemical vapor infiltration of fiber-reinforced composite materials with radio frequency heating. The model included equations for energy transport, multicomponent mass transport, and pore structure evolution, coupled to Maxwell's equations to determine self-consistently the power absorbed by the preform from a radio frequency induction coil. The model equations were solved by a finite element method to study carbon chemical vapor infiltration in a cylindrical carbon preform. Simulations for a constant absorbed power showed that densification of the preform proceeds in an "inside out" manner, first in the radial direction and subsequently in the axial direction, for the aspect ratio studied. The power density distribution in the preform evolves in a complex manner as densified regions absorb more energy with increased densification. This may result in thermal runaway during the infiltration process and entrapment of porosity in the interior of the preform. Comparison of simulated results with reported experimental data showed semiquantitative agreement of important trends. A more accurate description of material properties is required for a quantitative match with the data.

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“…[1][2][3][4][5][6][7] The main advantage of this technique, which results in the deposition of a ceramic matrix phase in a porous preform from the chemical breakdown of gaseous precursors, is that it can produce fibre reinforced ceramic matrix composites without thermally, mechanically or chemically degrading the preform fibres. 8,9 Microwave heated CVI (MCVI) is a potentially very attractive method for producing CMCs 6,10-15 since the inverse temperature profile generated across the preform by the microwave radiation (i.e. hotter centre) results in the porosity filling from the inside out, potentially resulting in a fully and homogeneously densified material in a reduced processing time.…”

Section: Introductionmentioning

confidence: 99%

“…The demand for fibre reinforced ceramic matrix composites has led to a significant degree of interest in chemical vapour infiltration (CVI) 1 – 7. The main advantage of this technique, which results in the deposition of a ceramic matrix phase in a porous preform from the chemical breakdown of gaseous precursors, is that it can produce fibre reinforced ceramic matrix composites without thermally, mechanically or chemically degrading the preform fibres 8. 9 Microwave heated CVI (MCVI) is a potentially very attractive method for producing CMCs6,10 – 15 since the inverse temperature profile generated across the preform by the microwave radiation (i.e.…”

Section: Introductionmentioning

confidence: 99%

Microwave heated chemical vapour infiltration of SiC powder impregnated SiC fibre preforms

Binner

Vaidhyanathan

Jaglin

2013

Advances in Applied Ceramics

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A microwave heated methyl trichlorosilane based chemical vapour infiltration technique has been used to form SiC f /SiC composites from SiC fibre preforms preimpregnated with SiC powder using two different fabrication techniques. While infiltration rates obtained from samples loaded with powder were generally higher than for preforms without powder, preferential infiltration occurred in regions where the SiC powder was most concentrated as a result of the initial non-uniform distribution of the powder across the preforms. The consequence was density gradients in the final composites. Nevertheless, average densities as high as 75% could be achieved in a 10 h process.

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Fiber-Reinforced Tubular Composites by Chemical Vapor Infiltration°

Cited by 13 publications

References 11 publications

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

Porous Membranes as Sacrificial Layers Enabling Conformal Chemical Vapor Deposition Involving Multiple Film-Forming Species

A Two‐Dimensional Model of Chemical Vapor Infiltration With Radio Frequency Heating

Microwave heated chemical vapour infiltration of SiC powder impregnated SiC fibre preforms

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