Thermochemical model on the carbothermal reduction of oxides during spark plasma sintering of zirconium diboride

David Pham, Joseph H. Dycus, James M. LeBeau, Venkateswara R. Manga, Krishna Muralidharan, Erica L Corral

Research output: Contribution to journalArticle

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Abstract

Carbon was used to reduce oxides in spark plasma sintered ZrB2 ultra-high temperature ceramics. A thermodynamic model was used to evaluate the reducing reactions to remove B2O3 and ZrO2 from the powder. Powder oxygen content was measured and carbon additions of 0.5 and 0.75 wt% were used. A C–ZrO2 pseudo binary diagram, ZrO2–B2O3–C pseudo ternaries, and Zr–C–O potential phase diagrams were generated to show how the reactions can be related to an open system experiment in the tube furnace. Scanning transmission electron microscopy identified impurity phases composed of amorphous Zr–B–O with lamellar BN and a Zr–C–O ternary model was calculated under SPS sintering conditions at 1900°C and 6 Pa to understand how oxides can be retained in the microstructure.

Original languageEnglish (US)
JournalJournal of the American Ceramic Society
DOIs
Publication statusAccepted/In press - Jan 1 2018

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Keywords

  • Field Assisted Sintering Technology (FAST)
  • phase diagrams
  • spark plasma sintering
  • ultra-high temperature ceramics

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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