KJ Ceramics 31

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Detailed Program

Paper Number : SY-O04

Time Frame : 17:00~17:15

Presentation Date : Thurse day, 27, November

Session Name : Synthesis, Raw Materials & Advanced powder processing

Session Chair 1# : Dong Sik Bae

Session Chair 2# : Kenji Toda

Synthesis and tribological characteristics of silicon carbide-derived carbon layer synthesized from different α- and β-SiC polytypes

Yoon-Soo CHUN

Korea University

Carbide-derived carbons (CDCs) were synthesized from two different carbide polytypes, which are hexagonal SiC (α-SiC) and cubic SiC (β-SiC) powders, by chlorination at temperatures between 900 and 1200°C. Also, hydrogen content was varied from 0 to 7.5 vol.%. The content of the sp2- and sp3-bonded carbon phases and their crystallinity were analyzed by Raman spectroscopy in our proveious report [1]. In this report, the mechanical properties were measured with tribological tests including friction coefficient and wear rate. The morphology of CDCs showed interesting features that varied with the starting SiC polytypes. Diamond nanocrystals were more frequently observed in α-SiC-derived carbon than that in β-SiC-derived carbon, which was investigated by CVD dimond deposition study as shonw in Fig.1. The rate of graphitization of CDCs was affected by not only synthesis temperature and hydrogen content but also SiC polytypes. A possible mechanism responsible for the observed results was also investigated. Tribological properties were measured with pin-on disk type tribometer. The β-SiC-derived carbon shows lower frcition coefficient that that of α-SiC-derived carbon due to higher graphitization of CDC layer. However, the wear rate measurements of both CDCs shows similar values but with different trend, where diamond nanocrystals are only formed on the surface of α-SiC-derived carbon to improve its hardness.
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Figure 1 SEM images of the surface of CDCs after the synthesis of CVD diamond: (a, b) are α-SiC-derived carbon, and (c, d) are β-SiC-derived carbon.

References:

[1] M.G. Jeong, S.H. Yoon, Y.S. Chun, E.S. Lee and D.S. Lim, Carbon 79 (2014) 19.

Acknowledgements :

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