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Time-resolved in-situ analysis of densification of nano-boron carbide under superimposed electric and thermal fields with energy dispersive x-ray diffraction

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Title
Time-resolved in-situ analysis of densification of nano-boron carbide under superimposed electric and thermal fields with energy dispersive x-ray diffraction
Name (type = personal)
NamePart (type = family)
Bicer
NamePart (type = given)
Hulya
DisplayForm
Hulya Bicer
Role
RoleTerm (authority = RULIB)
author
Name (type = personal)
NamePart (type = family)
Tsakalakos
NamePart (type = given)
Thomas
DisplayForm
Thomas Tsakalakos
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
chair
Name (type = corporate)
NamePart
Rutgers University
Role
RoleTerm (authority = RULIB)
degree grantor
Name (type = corporate)
NamePart
Graduate School - New Brunswick
Role
RoleTerm (authority = RULIB)
school
TypeOfResource
Text
Genre (authority = marcgt)
theses
OriginInfo
DateCreated (encoding = w3cdtf); (qualifier = exact)
2016
DateOther (qualifier = exact); (type = degree)
2016-01
CopyrightDate (encoding = w3cdtf); (qualifier = exact)
2016
Place
PlaceTerm (type = code)
xx
Language
LanguageTerm (authority = ISO639-2b); (type = code)
eng
Abstract (type = abstract)
Boron carbide (B4C) is characterized by high melting temperature, high hardness, and low density. Such exceptional properties make B4C is an important covalent solid which is considered the foremost material of choice for high-technology applications. However, low diffusivity caused by the highly directional and stiff character of the covalent bond makes the thermally activated sintering of B4C difficult. Highly covalent bonded ceramics are sintered with hot pressing and spark plasma sintering (SPS) to achieve high densities. However, these two techniques are limited to simple shape components and costly, involving expensive equipment. Pressureless sintering of B4C is desired to avoid expensive die designs and post sintering diamond machining, but very high sintering temperatures close to melting point is necessary to obtain high densities. Recently introduced flash sintering technique is a low voltage two electrode method which enhances the densification of ceramics. The sintering time and temperature can be reduced substantially with flash sintering that provide essential energy savings. In this study, the feasibility of flash sintering of nanoparticulate boron carbide is investigated. Firstly, we analyze the thermal expansion of boron carbide under different constant electric field strength to obtain fundamental data to provide insight into understanding of flash sintering. The electric field strength has an effect on the non-linear thermal expansion coefficients of B4C, and expansion becomes more non-linear with the increase of applied e-field. Secondly, the variety of non-isothermal and isothermal flash sintering experiments have been performed to achieve densification of B4C. By using low voltage, densities up to 95% of the theoretical density have been accomplished at temperatures as low as 711oC and short times on the order of few minutes. The very low process densification temperatures and time clearly indicate that mass transport in this nanoparticulate system under the action of both thermal and electrical fields are of an electrochemical origin. The implementation of ultrahigh energy EDXRD method in flash sintering of B4C enables us to monitor the evolution of nanoparticulate matter at the unit cell scale that is otherwise not possible with conventional Bragg-Brentano-method. EDXRD analysis reveals the transient anomalous unit cell expansion which is consistent with the flash sintering phenomena, and we demonstrate that flash sintering of B4C is possible with help of new coupling mechanism called the galvanomechanical effect. Moreover, we investigate the effect of different flash sintering conditions on densification of B4C.
Subject (authority = RUETD)
Topic
Materials Science and Engineering
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_6969
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (xi, 102 p. : ill.)
Note (type = degree)
Ph.D.
Note (type = bibliography)
Includes bibliographical references
Subject (authority = ETD-LCSH)
Topic
Carbides
Subject (authority = ETD-LCSH)
Topic
Boron
Subject (authority = ETD-LCSH)
Topic
Sintering
Note (type = statement of responsibility)
by Hulya Bicer
RelatedItem (type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier (type = local)
rucore19991600001
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
NjNbRU
Identifier (type = doi)
doi:10.7282/T32J6DXK
Genre (authority = ExL-Esploro)
ETD doctoral
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Rights

RightsDeclaration (ID = rulibRdec0006)
The author owns the copyright to this work.
RightsHolder (type = personal)
Name
FamilyName
Bicer
GivenName
Hulya
Role
Copyright Holder
RightsEvent
Type
Permission or license
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2016-01-05 13:30:09
AssociatedEntity
Name
Hulya Bicer
Role
Copyright holder
Affiliation
Rutgers University. Graduate School - New Brunswick
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License
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Author Agreement License
Detail
I hereby grant to the Rutgers University Libraries and to my school the non-exclusive right to archive, reproduce and distribute my thesis or dissertation, in whole or in part, and/or my abstract, in whole or in part, in and from an electronic format, subject to the release date subsequently stipulated in this submittal form and approved by my school. I represent and stipulate that the thesis or dissertation and its abstract are my original work, that they do not infringe or violate any rights of others, and that I make these grants as the sole owner of the rights to my thesis or dissertation and its abstract. I represent that I have obtained written permissions, when necessary, from the owner(s) of each third party copyrighted matter to be included in my thesis or dissertation and will supply copies of such upon request by my school. I acknowledge that RU ETD and my school will not distribute my thesis or dissertation or its abstract if, in their reasonable judgment, they believe all such rights have not been secured. I acknowledge that I retain ownership rights to the copyright of my work. I also retain the right to use all or part of this thesis or dissertation in future works, such as articles or books.
RightsEvent
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2016-01-31
DateTime (encoding = w3cdtf); (qualifier = exact); (point = end)
2018-01-30
Type
Embargo
Detail
Access to this PDF has been restricted at the author's request. It will be publicly available after January 30th, 2018.
Copyright
Status
Copyright protected
Availability
Status
Open
Reason
Permission or license
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ETD
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