Solute Distributions in Tantalum-Containing Zirconium Diboride Ceramics

Abstract

Solute segregation was examined in zirconium diboride and zirconium-tantalum diboride solid solution ceramics that were produced by reactive hot pressing. Microstructural analysis demonstrated that the ZrB2 and (Zr,Ta)B2 ceramics reached nearly full relative density and were nominally phase-pure. X-ray diffraction was consistent with full incorporation of Ta into solid solution within the ZrB2 structure, and energy-dispersive spectroscopy demonstrated that tantalum was well distributed throughout the bulk of the Ta-doped specimens. The weak characteristic X-rays for B led to inaccurate results for total atom concentrations in boride ceramics by energy-dispersive spectroscopy. Atom probe tomography was used to analyze the amount and spatial distribution of Ta species. No obvious Ta segregation was observed in grains or grain boundaries. However, nitrogen strongly segregated to a grain boundary. This study demonstrated that atom probe tomography is an accurate method for characterizing the amount and spatial distribution of metallic and nonmetallic species in ZrB2 ceramics.

Department(s)

Materials Science and Engineering

Comments

This work was funded by the Enabling Materials for Extreme Environments signature area at Missouri University of Science and Technology.

Keywords and Phrases

Atom Probe Tomography; Characterization; Segregation; Solid Solutions; Ultra-High Temperature Ceramics

International Standard Serial Number (ISSN)

0002-7820; 1551-2916

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 The American Ceramic Society, All rights reserved.

Publication Date

01 Apr 2020

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