The role of the pore surface area/pore volume ratio in chemical vapor infiltration

Isothermal, isobaric chemical vapor infiltration of carbon fiber felts with fiber volume fractions of 7.1% and 14.2% were investigated at infiltration times from 20 to 120 hours, using a constant temperature of 1095 oC and a methane pressure of 22.5 kPa. Bulk densities and the density profiles as well as porosity at various densification stages were determined. Inside–outside densification was obtained in the most infiltrations, the gradients of densification along the infiltration depth decrease with increasing of residence time and infiltration times. Outside–inside densification occurs only in the felt with the lower fiber volume fraction at final infiltration stage and at longer residence times. Microstructure of the obtained matrix carbon was analyzed with a polarized light microscopy. Abruptly change from low/medium textured carbon to medium/high textured carbon are observed in both of the carbon fiber felts, whereas the thickness of the first lower textured layer is about 14 micros in the felt with a fiber volume fraction of 7.1%, whereas it is only 2 micros in the felt with a fiber volume fraction of 14.2%, which is caused by an increasing of initial surface area / volume ratio, [A/V], from 33 to 71 mm-1. Results are completely in agreement with the previous simulations studies on the influence of [A/V] ratios.

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The Role of Gas‐Phase Reactions in Modeling of the Forced‐Flow Chemical Vapor Infiltration Process

Journal of The Electrochemical Society ◽

10.1149/1.2220776 ◽

1993 ◽

Vol 140 (7) ◽

pp. 2121-2124 ◽

Cited By ~ 7

Author(s):

Ching Yi Tsai ◽

Seshu B. Desu ◽

Chien C. Chiu ◽

J. N. Reddy

Keyword(s):

Gas Phase ◽

Chemical Vapor ◽

Chemical Vapor Infiltration ◽

Forced Flow ◽

Gas Phase Reactions ◽

Infiltration Process ◽

Vapor Infiltration

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The role of the substrate surface area/reactor volume ratio in chemistry and kinetics of chemical vapor deposition

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:1999810 ◽

1999 ◽

Vol 09 (PR8) ◽

pp. Pr8-79-Pr8-84 ◽

Cited By ~ 3

Author(s):

M. Teubner ◽

J. Antes ◽

Z. Hu ◽

W. Zhang ◽

K. J. Hüttinger

Keyword(s):

Chemical Vapor Deposition ◽

Surface Area ◽

Vapor Deposition ◽

Substrate Surface ◽

Volume Ratio ◽

Chemical Vapor ◽

Reactor Volume ◽

Kinetics Of

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Nano-Scale Pore Structure and Fractal Dimension of Longmaxi Shale in the Upper Yangtze Region, South China: A Case Study of the Laifeng–Xianfeng Block Using HIM and N2 Adsorption

Minerals ◽

10.3390/min9060356 ◽

2019 ◽

Vol 9 (6) ◽

pp. 356 ◽

Cited By ~ 16

Author(s):

Cheng Huang ◽

Yiwen Ju ◽

Hongjian Zhu ◽

Yu Qi ◽

Kun Yu ◽

...

Keyword(s):

Fractal Dimension ◽

Pore Structure ◽

Surface Area ◽

South China ◽

Pore Volume ◽

Pore Surface ◽

N2 Adsorption ◽

Longmaxi Shale ◽

Pore Surface Area ◽

Shale Reservoirs

This paper tries to determine the key evaluation parameters of shale reservoirs in the complex tectonic provinces outside the Sichuan Basin in South China, and also to target the sweet spots of shale reservoirs accurately. The pore-structure characteristics of the Lower Silurian Longmaxi shale gas reservoirs in Well LD1 of the Laifeng–Xianfeng Block, Upper Yangtze region, were evaluated. N2 adsorption and helium ion microscope (HIM) were used to investigate the pore features including pore volume, pore surface area, and pore size distribution. The calculated results show good hydrocarbon storage capacity and development potential of the shale samples. Meanwhile, the reservoir space and migration pathways may be affected by the small pore size. As the main carrier of pores in shale, organic matter contributes significantly to the pore volume and surface area. Samples with higher total organic carbon (TOC) content generally have higher porosity. Based on the Frenkel–Halsey–Hill equation (FHH model), two different fractal dimensions, D1 and D2, were observed through the N2 adsorption experiment. By analyzing the data, we found that large pores usually have large values of fractal dimension, owing to their complex pore structure and rough surface. In addition, there exists a good positive correlation between fractal dimension and pore volume as well as pore surface area. The fractal dimension can be taken as a visual indicator that represents the degree of development of the pore structure in shale.

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Gas transport model for chemical vapor infiltration

Journal of Materials Research ◽

10.1557/jmr.1995.2360 ◽

1995 ◽

Vol 10 (9) ◽

pp. 2360-2366 ◽

Cited By ~ 33

Author(s):

Thomas L. Starr

Keyword(s):

Transport Model ◽

Gas Permeability ◽

Chemical Vapor ◽

Structural Features ◽

Chemical Vapor Infiltration ◽

Model Parameters ◽

Fiber Loading ◽

Pore Surface Area ◽

Good Agreement ◽

Vapor Infiltration

A node-bond percolation model is presented for the gas permeability and pore surface area of the coarse porosity in woven fiber structures during densification by chemical vapor infiltration (CVI). Model parameters include the number of nodes per unit volume and their spatial distribution, and the node and bond radii and their variability. These parameters relate directly to structural features of the weave. Some uncertainty exists in the proper partition of the porosity between “node” and “bond” and between intra-tow and inter-tow, although the total is constrained by the known fiber loading in the structure. Applied to cloth layup preforms the model gives good agreement with the limited number of available measurements.

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