Crystalline carbonitride forms harder than the hexagonal Si-carbonitride crystallite

Fu, Yong Qing, Sun, Chang Qing, Du, Hejun and Yan, Bibo (2001) Crystalline carbonitride forms harder than the hexagonal Si-carbonitride crystallite. Journal of Physics D: Applied Physics, 34 (9). pp. 1430-1435. ISSN 0022-3727

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Abstract

It is shown that large and well faceted hexagonal crystallites can grow on Si and Ti substrates under higher nitrogen gas flow in the gaseous mixture of CH4 and H2 in the normal process of diamond deposition using microwave plasma chemical vapour deposition (MP-CVD). Grazing incidence x-ray diffraction (GIXRD), energy dispersive x-ray spectrometry (EDX), wavelength dispersive x-ray spectroscopy (WDX) and Raman analysis revealed that these crystals are silicon carbonitride rather than carbonitride as we expected and usually regarded. This indicates that the hypothetical covalent carbonitride is not as easily formed as the crystallite with Si substitution. Comparing films deposited on Ti alloy substrates, with and without Si chips present during the deposition, we found that the Si chips activated by the plasma sputtering provides Si sources for crystallite SiCN formation on Ti substrate. The hexagonal SiCN structure and its lower hardness are attributed to the C3v-symmetric quasi-tetrahedral nitride with a nonbonding lone pair. The involvement of the less electronegative Si specimen may make the SiCN form easier than the covalent carbonitride.

Item Type:	Article
Subjects:	F200 Materials Science
Department:	Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User:	Becky Skoyles
Date Deposited:	24 Mar 2015 16:21
Last Modified:	12 Oct 2019 19:05
URI:	http://nrl.northumbria.ac.uk/id/eprint/21768

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