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Densification and characterization of transparent polycrystalline spinel produced by spark plasma sintering

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TitleInfo
Title
Densification and characterization of transparent polycrystalline spinel produced by spark plasma sintering
Name (type = personal)
NamePart (type = family)
Vu
NamePart (type = given)
Minh T.
NamePart (type = date)
1978-
DisplayForm
Minh T. Vu
Role
RoleTerm (authority = RULIB)
author
Name (type = personal)
NamePart (type = family)
Haber
NamePart (type = given)
Richard
DisplayForm
Richard Haber
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
chair
Name (type = personal)
NamePart (type = family)
Lehman
NamePart (type = given)
Richard
DisplayForm
Richard Lehman
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
internal member
Name (type = personal)
NamePart (type = family)
Domnich
NamePart (type = given)
Vladislav
DisplayForm
Vladislav Domnich
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
internal member
Name (type = personal)
NamePart (type = family)
Gocmez
NamePart (type = given)
Hasan
DisplayForm
Hasan Gocmez
Affiliation
Advisory Committee
Role
RoleTerm (authority = RULIB)
outside member
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 (qualifier = exact)
2014
DateOther (qualifier = exact); (type = degree)
2014-10
CopyrightDate (encoding = w3cdtf)
2014
Place
PlaceTerm (type = code)
xx
Language
LanguageTerm (authority = ISO639-2b); (type = code)
eng
Abstract (type = abstract)
Polycrystalline transparent magnesium aluminate spinel (MgAl2O4) is an important optical material due to its good mechanical properties combined with a high light transmittance over the visible and near infrared wavelength range. It shows promise for many applications including high energy windows and light-weight armors. Being a difficult-to-sinter material, the fabrication of transparent spinel often requires a pressure-assisted sintering method with the use of a sintering aid. Thanks to its high heating rate combined with a moderate pressure, spark plasma sintering (SPS) is capable of producing a fine-grain spinel without using a sintering aid. The densification dynamics of spinel in SPS processing and its influence on the transmittance and the microstructure of the material were of great interest. Early in the course of study, it was determined that the mobility of the magnesium ions in spinel under an electric field at elevated temperatures was the major factor that caused discoloration in SPS-processed spinel. Controlling the SPS heating rate and soaking time after the sample reach 60% of its theoretical density was the decisive factor in attaining a high transmittance and minimizing discoloration. Later it was found that increasing the SPS processing time would diminish the transmittance of spinel in the visible region, and at the same time exacerbated discoloration. Based on these observations, the SPS conditions for transparent spinel were determined and optimized. Enhancement of the hardness of spinel by doping was also studied. A simple surface precipitation process was developed to coat alumina onto the spinel particles. Doping caused a reduction the transmittance of the material in the visible region but inserting an alumina layer between the graphite die and the powder compact to be sintered helped to solve this problem. By doping, the hardness of the material was increased by 3 – 6% compare to other SPS-processed spinels, and by about 8.5% compare to HIP-processed spinel of the same grain size. The findings of this dissertation explained why SPS processed spinel could not reach its theoretical transmittance in the visible wavelength range. Simple solutions to minimize discoloration of SPS-processed spinel were determined. The experimental designs served as a platform to explore potential densification dynamics and interactions of other nonconductive ceramic materials in SPS processing.
Subject (authority = RUETD)
Topic
Materials Science and Engineering
Subject (authority = ETD-LCSH)
Topic
Spinel
Subject (authority = ETD-LCSH)
Topic
Sintering
Subject (authority = ETD-LCSH)
Topic
Plasma
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_5775
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (xiv, 181 p. : ill.)
Note (type = degree)
Ph.D.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Minh T. Vu
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/T3R78GVC
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
Vu
GivenName
Minh
MiddleName
T.
Role
Copyright Holder
RightsEvent
Type
Permission or license
DateTime (encoding = w3cdtf); (qualifier = exact); (point = start)
2014-08-14 16:58:49
AssociatedEntity
Name
Minh Vu
Role
Copyright holder
Affiliation
Rutgers University. Graduate School - New Brunswick
AssociatedObject
Type
License
Name
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)
2014-10-31
DateTime (encoding = w3cdtf); (qualifier = exact); (point = end)
2015-10-31
Type
Embargo
Detail
Access to this PDF has been restricted at the author's request. It will be publicly available after October 31st, 2015.
Copyright
Status
Copyright protected
Availability
Status
Open
Reason
Permission or license
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RULTechMD (ID = TECHNICAL1)
ContentModel
ETD
OperatingSystem (VERSION = 5.1)
windows xp
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