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Journal of Inorganic Materials

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2007 , Vol. 22 >Issue 5: 991 - 995

DOI: https://doi.org/10.3724/SP.J.1077.2007.00991

Research Paper

Non-isothermal Oxidation Kinetics and Mechanisms of Polycrystalline Graphite

  • GUO Wei-Ming ,
  • XIAO Han-Ning ,
  • YASUDA Eiichi
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  • 1. College of Materials Science and Engineering, Hunan University, Changsha 410082, China; 2. Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan

Received date: 2006-09-26

  Revised date: 2006-11-17

  Online published: 2007-09-20

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Abstract

With the help of thermogravimetric analysis technique, non-isothermal oxidation kinetics of polycrystalline graphite was investigated by model-fitting and model-free methods, and the microstructure of the same surface of different weight loss was observed by SEM. Results show that the activation energy (E) depends strongly on weight loss fraction (α). Oxidation starts from grain boundary, and the pore size on observed surface almost does not change with the increase of weight loss at the initial stage of oxidation. The non-isothermal oxidation of polycrystalline graphite exhibites three regimes: in the initial stage (α<20%), oxidation is controlled by chemical reaction; in middle stage (20%<α<60%), oxidation is controlled by chemical reaction and gaseous diffusion; in final stage (α>60%), oxidation is controlled by gaseous diffusion. The model-free method is recommended as a trustworthy way for obtaining reliable kinetic information from non-isothermal oxidation of graphite.

Key words： polycrystalline graphite; non-isothermal oxidation; model-fitting method; model-free method

Cite this article

GUO Wei-Ming , XIAO Han-Ning , YASUDA Eiichi . Non-isothermal Oxidation Kinetics and Mechanisms of Polycrystalline Graphite[J]. Journal of Inorganic Materials, 2007 , 22(5) : 991 -995 . DOI: 10.3724/SP.J.1077.2007.00991

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