Hardness of α- and β-Si3−nCnN4 (n=0, 1, 2, 3) crystals

The hardness of alpha- and beta-Si3 - nCnN4 (n = 0, 1, 2, 3) crystals were calculated by using our microscopic model of hardness combined with first principles calculations. The results show that the hardness progressively increased with the increase of carbon content. Both C-rich alpha- and beta-Si...

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Bibliographic Details
Published in:Diamond and related materials 2009-01, Vol.18 (1), p.72-75
Main Authors: Du, H.J., Li, D.C., He, J.L., Yu, D.L., Xu, B., Liu, Z.Y., Wang, H.-T., Tian, Y.J.
Format: Article
Language:English
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Summary:The hardness of alpha- and beta-Si3 - nCnN4 (n = 0, 1, 2, 3) crystals were calculated by using our microscopic model of hardness combined with first principles calculations. The results show that the hardness progressively increased with the increase of carbon content. Both C-rich alpha- and beta-SiC2N4 phases are novel superhard materials whose hardness is at the range of 57-61 GPa, which can rival to that of c-BN. The two Si-rich SiC2N4 phases are also superhard materials, but their hardness is just higher than 40 GPa. The C-N bonds with short length and lower ionicity play key role to the increase of hardness. The Si-N bonds in the presented SiCN phases have shorter bond length than the binary silicon nitride and also contribute to the increase of hardness.
ISSN:0925-9635
DOI:10.1016/j.diamond.2008.09.025