Microhardness of ?ompacted thermally expanded graphite

Authors

  • S. L. Revo Taras Shevchenko National University of Kyiv https://orcid.org/0000-0002-1881-1472
  • M. M. Melnichenko Taras Shevchenko National University of Kyiv
  • T. G. Avramenko Taras Shevchenko National University of Kyiv
  • K. O. Ivanenko Taras Shevchenko National University of Kyiv
  • V. O. Andruschenko Taras Shevchenko National University of Kyiv

DOI:

https://doi.org/10.17721/1812-5409.2019/1.40

Abstract

Using the method of continuous microindentation with different loading on the indenter, the microhardness of compacted thermo-expanded graphite (TEG) samples of different dispersion was studied. The analysis of the obtained results showed that, with an increase in the average cross-sectional area of TEG particles from 40 to 120 microns, the microhardness of the samples under investigation also increases. An analysis of the influence of the dispersion and morphology of the TEG particles on the distribution of microhardness on the surface of the compacted samples of TEG was also carried out. The microhardness indicatrix for the samples of the original TEG shows that when the radial displacement from the center of the sample, the microhardness of the material decreases. So in the central part of the discoid sample the values of microhardness lie in the range from 0,04 to 0,025 GPa. In the next concentric region, the microhardness decreases by 30% and gains a value of (0.028 ... 0.014) GPA. When the dispersion of TEG particles changes, the distribution of microhardness also changes. The microhardness indicatrix for a compacted Tg sample with an average particle size of 180 ?m shows that the microhardness value at the center of the sample ranges from 0.065 to 0.15 GPa.As you approach the edge of the sample, the microhardness of the material decreases from 0.15 to 0.054 GPa. The study of TEG with an average particle size of 50 ?m showed that the indentation in the center and in the middle region of the sample gives an isotropic distribution of microhardness values. The microhardness values coincide in the central and middle regions of the sample and correspond to ? 0.1 GPa. The proposed method of research and analysis of microhardness on the surface of compacted specimens of TEG gives an opportunity not only to characterize the micromechanical properties of the investigated material but also to optimize the technological regimes for obtaining samples.

Key words: micromechanical properties, graphite, microhardness, thermo-expanded graphite.

Pages of the article in the issue: 174-177

Language of the article: Ukrainian

References

SEMENTSOV YU.I, REVO S.L, IVANENKO K.O. (2016) Thermally exfoliated graphite. Kyiv: Interservis.

AVRAMENKO T.G., KHUTORYANSKAYA N.V., MIKHALYUK O.V. et al. (2016) Structure and sorption characteristics of nanoporous carbon materials. Surf Eng Appl Elect. 52(4). р. 313-318.

REVO S.L, BUDZULYAK I.M., RACHIY B.I., and KUZISHIN M.M. (2013) Electrode Material for Supercapacitors Based on Nanostructured Carbon. Surf Eng Appl Elect. 49(1). p. 68-72.

MIYOSHI K. (2002) Surface characterization techniques: an overview. NASA/TM 2002- 211497, Glenn Research Center of NASA. p. 45.

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How to Cite

Revo, S. L., Melnichenko, M. M., Avramenko, T. G., Ivanenko, K. O., & Andruschenko, V. O. (2019). Microhardness of ?ompacted thermally expanded graphite. Bulletin of Taras Shevchenko National University of Kyiv. Physical and Mathematical Sciences, (1), 174–177. https://doi.org/10.17721/1812-5409.2019/1.40

Issue

Section

Differential equations, mathematical physics and mechanics