Molecular Dynamics Simulation of Vacancy Cluster Formation in ��- and ��-$Si_3N_4$
| Autor: | Adabifiroozjaei, E., Mofarah, S. S., Ma, H., Jiang, Y., Assadi, M. H. N., Suzuki, T. S. |
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| Rok vydání: | 2020 |
| Předmět: | |
| DOI: | 10.48550/arxiv.2003.13051 |
| Popis: | Molecular dynamics simulation is used to study vacancy cluster formation in $��$- and $��$-$Si_3N_4$ with varying vacancy contents (0 - 25.6 at%). Vacancies are randomly created in supercells, which were subsequently heat-treated for 114 nanoseconds. The results show that both $��$ and $��$ can tolerate vacancies up to 12.8 at% and form clusters, confirming previous experimental data indicating 8 at% vacancy in $��$-$Si_3N_4$. However, 25.6 at% vacancy in $��$ results in complete amorphization, while the same amount in $��$ results in a transformation of a semi-amorphous $��$ phase to a defective $��$ phase, leading to the removal of the clusters in newly formed $��$. This clearly explains why cluster vacancies are not experimentally observed in $��$, considering that $��$-$Si_3N_4$ ceramics are produced from $��$. Furthermore, the lattice parameters of both modifications increase with increasing vacancy content, revealing the cause of different lattice constants that were previously reported for $��$-$Si_3N_4$. 6 pages, 4 figures, 1 table, journal article |
| Databáze: | OpenAIRE |
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