Boron-rich amorphous boron oxides from ab initio simulations

Karacaoğlan A. Ö. Ç., DURANDURDU M.

Journal of Non-Crystalline Solids, vol.604, 2023 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 604
  • Publication Date: 2023
  • Doi Number: 10.1016/j.jnoncrysol.2022.122130
  • Journal Name: Journal of Non-Crystalline Solids
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Keywords: ab initio, Amorphous, Boron oxides, Boron-rich
  • Abdullah Gül University Affiliated: Yes

Abstract

Amorphous boron oxide (BxO1-x, 0.5 ≤ x ≤ 95) configurations are simulated by means of an ab initio molecular dynamics technique and their microstructure and mechanical properties are revealed in details. With increasing B content, the average B-coordination noticeably increases from 3.18 to 5.62 whereas the O-coordination, surprisingly, remains almost null, about 2.0. The formation of complete B12 molecules is observed after 80% B concentrations. Chemical segregation is witnessed in most models and hence the resulting configurations show B:B2O3 phase separations. The mechanical properties (bulk, shear and Young moduli, Vickers hardness and microhardness) substantially increase with increasing B content. The amorphous materials (BxO1-x, x≥80)are classified as hard materials. Within the limitations of DFT calculations and approaches used, we speculate that there is a ductile-to-brittle transition at around 70–75% B contents.