Investigation of Changes in the Fine Structure of Graphitizing Carbon Materials during Heat Treatment by X-Ray Diffraction Analysis

Vasiliy A Tyumentsev,Alfiya G Fazlitdinova

doi:10.4236/msce.2020.810002

Vasiliy A Tyumentsev, Alfiya G Fazlitdinova

Open Access

https://doi.org/10.4236/msce.2020.810002

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Abstract

The properties of synthetic graphite materials, widely used in advanced fields, are determined by their structure, which is formed in the process of high-temperature (~2500°C) heat treatment. The fine structure of a graphitizing carbon material based on petroleum coke containing 1.3 wt% S at various stages of graphitization was studied by X-ray diffraction analysis. Some of the samples contained the addition of dispersed Fe2O3. It is shown that the heat-treated material in the range 1200°C - 2600°C is heterogeneous, its component composition is determined by the processing temperature and the presence of Fe2O3 additive. The observed dependence of the component composition on the heat treatment temperature suggests that the process of graphitization of the carbon material, apparently, develops through a number of metastable states.

Highlights

Graphite materials, carbon fibers, and carbon-carbon composites are widely used in advanced areas that provide technical progress
According to the literature [8] [9], up to six metastable states can be realized in a carbon material, which correspond to the values of the interplanar distance: d1002
The profile of the (002) peak of a carbon material heat-treated at 1200 ̊C can be confidently decomposed into two components, which we denote as C5 and C6 (d5002~0.344 and d6002~0.359 nm), coefficient R2 = 0.9977, Table 1

Summary

Introduction

Carbon fibers, and carbon-carbon composites are widely used in advanced areas that provide technical progress. To diagnose changes in the structure of carbon materials at different stages of production, to study the effect of special additives, X-ray diffraction analysis methods are widely used to determine the degree of graphitization, dispersed and phase composition, and texture parameters [3] [4]. A number of studies have observed a stepwise change in the interplanar distance during heat treatment, neutron irradiation, or long-term mechanical dispersion [8]-[13]. It was assumed [8] [9] that metastable states with differing in the value of d002 can form in carbon materials.

Experimental

Results and Discussion

Conclusions