Countercurrent Gaseous Diffusion Model of Oxidation Through a Porous Coating

Holcomb, Gordon R.

doi:10.5006/1.3292143

Cited by 10 publications

(4 citation statements)

References 5 publications

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“…These applications include the burnout of carbon between two alumina plates (6), the oxidation of TaC (7,8), oxidation of carbon fiber coatings in composites (9)(10)(11), and the oxidation of carbon in an alumina matrix (12). In the case of TaC oxidation, a porous oxide forms as an outer layer and oxidation occurs through the pores.…”

mentioning

confidence: 99%

Oxidative attack of carbon/carbon substrates through coating pinholes

Jacobson

Leonhardt

Curry

et al. 1999

Carbon

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confidence: 99%

Oxidative attack of carbon/carbon substrates through coating pinholes

Jacobson

Leonhardt

Curry

et al. 1999

Carbon

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“…Owing to the small size and uniform distribution of SiC, the formed passages for the diffusion of oxidative species and silicon oxide in HfO 2 skeleton were less than 2 μm in size. The results of Holcomb's study [40] showed that when the pore size of diffusion medium was less than 10 μm, the effect of Knudsen diffusion could not be ignored, and increased with the decrease of pore size. Yang et al [41] reported that Knudsen diffusion tended to contribute dominantly when the average pore size of diffusion medium was 2 μm.…”

Section: Resultsmentioning

confidence: 99%

Ablation of C/SiC-HfC composite prepared by precursor infiltration and pyrolysis in plasma wind tunnel

Duan

Luo²,

Liu

et al. 2020

J Adv Ceram

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Carbon fiber reinforced silicon carbide-hafnium carbide (C/SiC-HfC) composite was prepared by precursor infiltration and pyrolysis process. Then, ablation behavior of C/SiC-HfC was evaluated in plasma wind tunnel. It was found that oxide layer formed during ablation significantly influenced the surface temperature. Formation of dense HfO 2-SiO 2 layer under low heat flux led to stable surface temperature. Silica (SiO 2) on the surface was gradually consumed when heat flux increased, resulting in conversion of HfO 2-SiO 2 on the surface to HfO 2. Converted HfO 2 with high catalytic coefficient absorbed more energy, causing gradual increase in the surface temperature. Formed oxide layer was destroyed at high heat flux and high stagnation point pressure. After carbon fiber lost the protection of HfO 2-SiO 2 layer, it burned immediately, leading to surface temperature jump.

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“…There are several studies in the literature of carbon oxidation through channels (slots or cracks) in an inert matrix (5)(6)(7)(8)(9)(10)(11)(12)(13). The equations for this type of oxidation are well established and have been presented by these authors.…”

Section: Oxidation Modelingmentioning

confidence: 99%

“…As discussed, these equations have been solved analytically by several authors (6)(7)(8)(9)(10)(11)(12). The first step is to derive an expression for x f /L .…”

Section: Oxidation Modelingmentioning

confidence: 99%

Oxidation of Carbon/Carbon through Coating Cracks

et al. 2009

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Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonable.

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Countercurrent Gaseous Diffusion Model of Oxidation Through a Porous Coating

Cited by 10 publications

References 5 publications

Oxidative attack of carbon/carbon substrates through coating pinholes

Oxidative attack of carbon/carbon substrates through coating pinholes

Ablation of C/SiC-HfC composite prepared by precursor infiltration and pyrolysis in plasma wind tunnel

Oxidation of Carbon/Carbon through Coating Cracks

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