Issue 1, 1983

Kinetics of monticular carbon growth on polycrystalline iron

Abstract

The kinetics of carbon deposition on polycrystalline iron surfaces from methane at 750 Torr pressure and at temperatures between 1013 and 1133 K have been studied using the change in power dissipation of an electrically heated filament caused by the increased emissivity as the surface is blackened by deposit. The carbon formed has a monticular-type structure. The growth kinetics follow a direct logarithmic rate law which is explained in terms of the availability of active sites at the surface. The total carbon uptake at maximum coverage of the monticular layer, i.e. at maximum emissivity, depends on the filament temperature and can be correlated with the amount of carbon taken up into solution during the prior induction period in accordance with the phase diagram. The activation energy has a value of 66 ± 8 kJ mol–1. The rate-determining step for monticular growth cannot be established, but certain possibilities, such as carbon dissolution, bulk diffusion of carbon in the metal, and surface and bulk self-diffusion of iron, can be eliminated. Various aspects of the mechanism of formation of the monticular growths are discussed.

Article information

Article type
Paper

J. Chem. Soc., Faraday Trans. 1, 1983,79, 15-26

Kinetics of monticular carbon growth on polycrystalline iron

A. M. Emsley and M. P. Hill, J. Chem. Soc., Faraday Trans. 1, 1983, 79, 15 DOI: 10.1039/F19837900015

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements