MOLECULAR-DYNAMICS STUDY OF NA-SI-O-N OXYNITRIDE GLASSES

Citation
H. Unuma et al., MOLECULAR-DYNAMICS STUDY OF NA-SI-O-N OXYNITRIDE GLASSES, Journal of the American Ceramic Society, 76(5), 1993, pp. 1308-1312
Citations number
26
Categorie Soggetti
Material Science, Ceramics
ISSN journal
00027820
Volume
76
Issue
5
Year of publication
1993
Pages
1308 - 1312
Database
ISI
SICI code
0002-7820(1993)76:5<1308:MSONOG>2.0.ZU;2-V
Abstract
The structure and properties of Na-Si-O-N oxynitride glasses have been studied by molecular dynamics calculations using a pair potential of- the Busing approximation of the Born-Mayer-Huggins type. Nitrogen atom s bonded to one, two, and three silicon atoms coexist in the glass str ucture. The mean of the number of silicon atoms bonded to a nitrogen a tom ranges from 2.4 to 2.1, decreasing with increasing Na2O content fr om 15 to 30 mol%. It has been assumed that nitrogen atoms bonded to tw o or fewer silicon atoms are formed when nitrogen atoms substitute for non-bridging atoms. The bond angle angle Si-N-Si exhibits a bimodal d istribution around 105-135-degrees and 140-170-degrees, roughly corres ponding to the nitrogen atoms bonded to three and two silicon atoms, r espectively. The dependences of the density, the bulk thermal expansio n, and the bulk modulus on the nitrogen content are consistent with th ose observed in real systems.