Hexagonal Osb2: Sintering, Microstructure And Mechanical Properties

Keywords

Ceramic; Mechanical properties; Nanoindentation; Osmium diboride

Abstract

The metastable high pressure ReB2-type hexagonal OsB2 bulk ceramics was produced by spark plasma sintering. The phase composition, microstructure, and mechanical behavior of the sintered OsB2 were studied by X-ray diffraction, optical microscopy, TEM, SEM, EDS, and nanoindentation. The produced ceramics was rather porous and contained a mixture of hexagonal (∼80 wt.%) and orthorhombic (∼20 wt.%) phases as identified by X-ray diffraction and EBSD analysis. Two boron-rich phases, which do not contain Os, were also identified by TEM and SEM/EDS analysis. Nanoindentation measurements yielded a hardness of 31 ± 9 GPa and Young's modulus of 574 ± 112 GPa, indicating that the material is rather hard and very stiff; however, it is very prone to crack formation and propagation, which is indicative of a very brittle nature of this material. Improvements in the sintering regime are required in order to produce dense, homogeneous and single phase hexagonal OsB2 bulk ceramics.

Publication Date

6-5-2015

Publication Title

Journal of Alloys and Compounds

Volume

634

Number of Pages

168-178

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.jallcom.2015.01.291

Socpus ID

84923578551 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84923578551

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