Modeling and simulation of materials synthesis: Chemical vapor deposition and infiltration of pyrolytic carbon

Abstract

International audienc

Mesoporous alumina infiltrated with a very thin and complete carbon layer

“…The benefits of pyrocarbon infiltration in mesoporous alumina for the synthesis of CCA composites are obvious: the process is technologically simple (a single-step procedure), the necessary reagents are available in abundance and at affordable prices. However, the CVI process has some drawbacks: (1) it is a long-term process, (2) as the mechanism of CVI/CVD reactions on the surface of porous substrates is very complex, it is a challenge to reveal conditions ensuring the complete and continuous coating of alumina surface with a thin layer of pyrolytic carbon [22,23,25]. Herein we report that the mesoporous carbon-infiltrated alumina composite with a very thin (1e1.5 carbon layers) and uniformly dispersed carbon coating was obtained by CVI of pyrocarbon in the g-Al 2 O 3 matrix at 750e800 C using the C 2 H 4 /Ar gas feedstock (1 bar).…”

A molecular-level analysis of gas-phase reactions in chemical vapor deposition of carbon from methane using a detailed kinetic model

“…At the residence time of about 1 s, mole fractions of acetylene and benzene show a decreasing trend in experiments, which is the influence of surface reactions. Carbon in solid state, which is believed to be probably generated by acetylene and benzene [1,31], may appear in the experiments and play a more important role in the methane pyrolysis as the residence time increases. The further work including the surface reactions will explain the phenomena in detail.…”

Microstructure and Mechanical Properties of Lu2O3‐Doped Porous Silicon Nitride Ceramics Using Phenolic Resin as Pore‐Forming Agent

“…29,30 The internal surface area of porous ceramic varies continuously due to the progressive densification, which dramatically influences the interactions of gasphase and surface kinetics in the micropores. 30,31 When performed in isothermal and isobaric conditions, the deposition reaction provokes an internal reactant depletion, [30][31][32] which eventually leads to a different deposit thickness between the inner and the surface of the porous Si 3 N 4 . The densifications of the inner and the surface of the porous ceramic lead to the increase of the mechanical properties.…”