High temperature Ir segregation in Ir-B ceramics: Effect of oxygen presence on stability of IrB2 and other Ir-B phases

Z. Xie, A. C. Terracciano, D. A. Cullen, R. G. Blair, N. Orlovskaya

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The formation of IrB2, IrB1.35, IrB1.1 and IrB monoboride phases in the Ir-B ceramic nanopowder was confirmed during mechanochemical reaction between metallic Ir and elemental B powders. The Ir-B phases were analysed after 90 h of high energy ball milling and after annealing of the powder for 72 h at 1050°C in vacuo. The iridium monoboride (IrB) orthorhombic phase was synthesised experimentally for the first time and identified by powder X-ray diffraction. Additionally, the ReB2 type IrB2 hexagonal phase was also produced for the first time and identified by high resolution transmission electron microscope. Ir segregation along disordered domains of the boron lattice was found to occur during high temperature annealing. These nanodomains may have useful catalytic properties.

Original languageEnglish
Pages (from-to)429-435
Number of pages7
JournalAdvances in Applied Ceramics
Volume114
Issue number8
DOIs
StatePublished - Nov 2015

Funding

This work was supported by NSF project DMR-0748364. Electron microscopy was performed as part of a user project supported by ORNL''s Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility.

Keywords

  • Catalyst
  • Ceramics
  • Ir Segregation
  • Iridium diboride
  • Mechanochemistry
  • Metal Clustering

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