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

Journal Article · Wed May 13 00:00:00 EDT 2015 · Advances in Applied Ceramics

DOI:https://doi.org/10.1179/1743676115Y.0000000002· OSTI ID:1265282

Xie, Zhilin ^[1]; Terracciano, Anthony C. ^[1]; Cullen, David A. ^[2]; Blair, Richard G. ^[1]; Orlovskaya, Nina ^[1]

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1. Univ. of Central Florida, Orlando, FL (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The formation of IrB₂, IrB_1.35, IrB_1.1 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. Furthermore, these nanodomains may have useful catalytic properties.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1265282
• Journal Information: Advances in Applied Ceramics, Vol. 114, Issue 8; ISSN 1743-6753
• Publisher: Taylor & Francis
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
iridium diboride
mechanochemistry
ceramics
Ir segregation
metal clustering
catalyst