Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations
The fractions of aluminium, [Al]/[Al+Si], and oxygen, [O]/[O] in crystallographically distinct sites of BaYb[Si4-xAlxOxN7-x] oxonitridoaluminosilicate (space group P63mc, No. 186) were refined based on the results of neutron powder diffraction for a synthetic sample with the composition of x 2.2(2)...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
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R Oldenbourg Verlag
2007
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| Online Access: | http://hdl.handle.net/20.500.11937/46921 |
| _version_ | 1848757692874620928 |
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| author | Vinograd, V. Juarez-Arellano, E. Leib, A. Knorr, K. Schnick, W. Gale, Julian Winkler, B. |
| author_facet | Vinograd, V. Juarez-Arellano, E. Leib, A. Knorr, K. Schnick, W. Gale, Julian Winkler, B. |
| author_sort | Vinograd, V. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The fractions of aluminium, [Al]/[Al+Si], and oxygen, [O]/[O] in crystallographically distinct sites of BaYb[Si4-xAlxOxN7-x] oxonitridoaluminosilicate (space group P63mc, No. 186) were refined based on the results of neutron powder diffraction for a synthetic sample with the composition of x 2.2(2) and simulated as functions of temperature for the compositions x 2 and x 2.3 using a combination of static lattice energy calculations (SLEC) and Monte Carlo simulations. The SLEC calculations have been performed on a set of 800 structures differing in the distribution of Al/Si and O/N within the 2 2 2 supercell containing 36 formula units of BaYb[Si4-xAlxOxN7-x]. The SLEC were based on a transferable set of empirical interatomic potentials developed within the present study. The static lattice energies of these structures have been expanded in the basis set of pair-wise ordering energies and on-site chemical potentials. The ordering energies and the chemical potentials have been used to calculate the configuration energies of the oxonitridoaluminosilicates (so-called sialons) using a Monte Carlo algorithm. The simulations suggest that Al and O are distributed unevenly over two non-equivalent T(Si/Al) and three L(N/O) sites, respectively, and the distribution shows strong dependence both on the temperature and the composition. Both simulated samples exhibit order/disorder transitions in the temperature range 500-1000 K to phases with partial long-range order below these temperatures. Above the transition temperatures the Si/Al and N/O distributions are affected by short-range ordering. The predicted site occupancies are in a qualitative agreement with the neutron diffraction results. |
| first_indexed | 2025-11-14T09:32:08Z |
| format | Journal Article |
| id | curtin-20.500.11937-46921 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:32:08Z |
| publishDate | 2007 |
| publisher | R Oldenbourg Verlag |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-469212018-03-29T09:07:32Z Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations Vinograd, V. Juarez-Arellano, E. Leib, A. Knorr, K. Schnick, W. Gale, Julian Winkler, B. Monte Carlo simulation Cation and anion ordering Neutron scattering Oxonitridoaluminosilicate Powder diffraction structure analysis Substitution effects Sialon The fractions of aluminium, [Al]/[Al+Si], and oxygen, [O]/[O] in crystallographically distinct sites of BaYb[Si4-xAlxOxN7-x] oxonitridoaluminosilicate (space group P63mc, No. 186) were refined based on the results of neutron powder diffraction for a synthetic sample with the composition of x 2.2(2) and simulated as functions of temperature for the compositions x 2 and x 2.3 using a combination of static lattice energy calculations (SLEC) and Monte Carlo simulations. The SLEC calculations have been performed on a set of 800 structures differing in the distribution of Al/Si and O/N within the 2 2 2 supercell containing 36 formula units of BaYb[Si4-xAlxOxN7-x]. The SLEC were based on a transferable set of empirical interatomic potentials developed within the present study. The static lattice energies of these structures have been expanded in the basis set of pair-wise ordering energies and on-site chemical potentials. The ordering energies and the chemical potentials have been used to calculate the configuration energies of the oxonitridoaluminosilicates (so-called sialons) using a Monte Carlo algorithm. The simulations suggest that Al and O are distributed unevenly over two non-equivalent T(Si/Al) and three L(N/O) sites, respectively, and the distribution shows strong dependence both on the temperature and the composition. Both simulated samples exhibit order/disorder transitions in the temperature range 500-1000 K to phases with partial long-range order below these temperatures. Above the transition temperatures the Si/Al and N/O distributions are affected by short-range ordering. The predicted site occupancies are in a qualitative agreement with the neutron diffraction results. 2007 Journal Article http://hdl.handle.net/20.500.11937/46921 10.1524/zkri.2007.222.8.402 R Oldenbourg Verlag restricted |
| spellingShingle | Monte Carlo simulation Cation and anion ordering Neutron scattering Oxonitridoaluminosilicate Powder diffraction structure analysis Substitution effects Sialon Vinograd, V. Juarez-Arellano, E. Leib, A. Knorr, K. Schnick, W. Gale, Julian Winkler, B. Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title | Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title_full | Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title_fullStr | Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title_full_unstemmed | Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title_short | Coupled A1/Si and O/N order/disorder in BaYb[Si4-xA1xOxN7-x] sialon: neutron powder diffraction and Monte Carlo simulations |
| title_sort | coupled a1/si and o/n order/disorder in bayb[si4-xa1xoxn7-x] sialon: neutron powder diffraction and monte carlo simulations |
| topic | Monte Carlo simulation Cation and anion ordering Neutron scattering Oxonitridoaluminosilicate Powder diffraction structure analysis Substitution effects Sialon |
| url | http://hdl.handle.net/20.500.11937/46921 |