Molecular dynamics simulation of vacancy cluster formation in β- and α-Si3N4

E. Adabifiroozjaei*, S. S. Mofarah, H. Ma, Y. Jiang, M. Hussein N. Assadi, T. S. Suzuki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Molecular dynamics simulation is used to study vacancy cluster formation in β- and α-Si3N4 with varying vacancy contents (0–25.6 at%). Vacancies are randomly created in supercells, which were subsequently heat-treated for 114 ns. The results show that both β and α can tolerate vacancies up to 12.8 at% and form clusters, confirming previous experimental data indicating 8 at% vacancy in α-Si3N4. However, 25.6 at% vacancy in β results in complete amorphization, while the same amount in α results in a transformation of a semi-amorphous α phase to a defective β phase, leading to the removal of the clusters in newly formed β. This clearly explains why cluster vacancies are not experimentally observed in β, considering that β-Si3N4 ceramics are produced from α. Furthermore, the lattice parameters of both modifications increase with increasing vacancy content, revealing the cause of different lattice constants that were previously reported for α-Si3N4.

Original languageEnglish
Article number109632
JournalComputational Materials Science
Volume178
DOIs
Publication statusPublished - 2020 Jun 1
Externally publishedYes

Keywords

  • MD simulation
  • Silicon nitride
  • Vacancy cluster

ASJC Scopus subject areas

  • Computer Science(all)
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Physics and Astronomy(all)
  • Computational Mathematics

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