Title:
Solution-based synthesis and processing of nanocrystalline ZrB₂-based composites

dc.contributor.advisor Speyer, Robert F.
dc.contributor.advisor Sanders, Thomas H., Jr.
dc.contributor.author Xie, Yanli en_US
dc.contributor.committeeMember Gerhardt, Rosario
dc.contributor.committeeMember Sandhage, Kenneth
dc.contributor.committeeMember Snyder, Robert
dc.contributor.committeeMember Zhang, John
dc.contributor.department Materials Science and Engineering en_US
dc.date.accessioned 2009-01-22T15:53:00Z
dc.date.available 2009-01-22T15:53:00Z
dc.date.issued 2008-11-24 en_US
dc.description.abstract Zirconium- and tantalum-based diborides, and diboride/carbide composites are of interest for ultra-high temperature applications requiring improved thermomechanical and thermochemical stability. This thesis focuses on the synthesis, processing and sintering of nanocrystalline powders with Zr- and Ta-based diboride/carbide/silicide compositions. A solution-based processing method was developed to prepare reactive mixtures that were precursors for ZrB₂-based powders. The precursors reacted to form the ceramic powders after suitable pyrolysis and borothermal/carbothermal reduction heat treatments. Single-phase ZrB₂ powders were prepared with initial composition of C/Zr = 4.8 and B/Zr = 3.0. ZrB₂-based composite powders with ZrC, ZrO₂, TaB₂, TaC, SiC, TaSi₂ and B₄C were prepared with particle sizes of 10-500 nm for different phases based SEM micrographs. The composite powders were highly sinterable with proper processing methods developed to avoid and remove oxide impurities. The relative densities of ZrB₂/B₄C, ZrB₂/TaB₂, ZrB₂/TaB₂/B4C, ZrB₂/TaSi₂ were in the range of 91%-97% after pressureless sintering at 2020 ℃ for 1 h or 30 min. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/26640
dc.publisher Georgia Institute of Technology en_US
dc.subject Sol-gel en_US
dc.subject Nanocystalline en_US
dc.subject Synthesis en_US
dc.subject Zirconium boride en_US
dc.subject.lcsh Nanocrystals Synthesis
dc.subject.lcsh Zirconium
dc.subject.lcsh Tantalum
dc.subject.lcsh Exterme environments
dc.title Solution-based synthesis and processing of nanocrystalline ZrB₂-based composites en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Speyer, Robert F.
local.contributor.corporatename School of Materials Science and Engineering
local.contributor.corporatename College of Engineering
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relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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