The Resource Thermal properties of spinel based solid solutions, by Kelley Rae Oh'Hara

Thermal properties of spinel based solid solutions, by Kelley Rae Oh'Hara

Label
Thermal properties of spinel based solid solutions
Title
Thermal properties of spinel based solid solutions
Statement of responsibility
by Kelley Rae Oh'Hara
Creator
Contributor
Author
Sponsor
Subject
Language
eng
Summary
"Solid solution formation in spinel based systems proved to be a viable approach to decreasing thermal conductivity. Samples with systematically varied additions of MgGa2O4 to MgAl2O4 were prepared and thermal diffusivity was measured using the laser ash technique. Additionally, heat capacity was measured using differential scanning calorimetry and modeled for the MgAl2O4-MgGa2O4 system. At 200°C thermal conductivity decreased 24% with a 5 mol% addition of MgGa2O4 to the system. The solid solution continued to decrease the thermal conductivity by 13% up to 1000°C with 5 mol% addition. The decrease in thermal conductivity ultimately resulted in a decrease in heat flux when applied to a theoretical furnace lining, which could lead to energy savings in industrial settings. The MgAl2O4-Al2O3 phase equilibria was investigated to fully understand the system and the thermal properties at elevated temperatures. The solvus line between MgAl2O4 and Al2O3 has been defined at 79.6 wt% Al2O3 at 1500°C, 83.0 wt% Al2O3 at 1600°C, and 86.5 wt% Al2O3 at 1700°C. A metastable region has been identified at temperatures up to 1700°C which could have significant implications for material processing and properties. The spinel solid solution region has been extended to form an infinite solid solution with Al2O3 at elevated temperatures. A minimum in melting at 1975°C and a chemistry of 96 wt% Al2O3 rather than a eutectic is present. Thermal properties in the MgAl2O4-Al2O3 system were investigated in both the single phase solid solution region and the two phase region. The thermal diffusivity decreased through the MgAl2O4 solid solution region and was at a minimum through the entire metastable (nucleation and growth) region. As Al2O3 became present as a second phase the thermal diffusivity increased with Al2O3 content. There was an 11.7% increase in thermal diffusivity with a change in overall chemistry of 85.20 wt% Al2O3 to 87.71 wt% Al2O3, due to the drastic change in final chemistry (38.3 wt% Al2O3) caused by the nucleation and growth region in the system"--Abstract, leaf iv
Related
Member of
Cataloging source
UMR
http://library.link/vocab/creatorDate
1985-
http://library.link/vocab/creatorName
O'Hara, Kelley Rae
Degree
Ph. D.
Dissertation year
2012.
Granting institution
Missouri University of Science and Technology
Illustrations
illustrations
Index
no index present
Literary form
non fiction
Nature of contents
theses
http://library.link/vocab/relatedWorkOrContributorName
United States
http://library.link/vocab/subjectName
  • Spinel
  • Phase rule and equilibrium
  • Thermal conductivity
Label
Thermal properties of spinel based solid solutions, by Kelley Rae Oh'Hara
Instantiates
Copyright
Note
Vita
Bibliography note
Includes bibliographical references
Carrier category
volume
Carrier category code
  • nc
Carrier MARC source
rdacarrier.
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent.
Control code
829130709
Dimensions
29 cm
Extent
xiii, 158 leaves
Media category
unmediated
Media MARC source
rdamedia.
Media type code
  • n
Other physical details
illustrations
System control number
(OCoLC)829130709
Label
Thermal properties of spinel based solid solutions, by Kelley Rae Oh'Hara
Copyright
Note
Vita
Bibliography note
Includes bibliographical references
Carrier category
volume
Carrier category code
  • nc
Carrier MARC source
rdacarrier.
Content category
text
Content type code
  • txt
Content type MARC source
rdacontent.
Control code
829130709
Dimensions
29 cm
Extent
xiii, 158 leaves
Media category
unmediated
Media MARC source
rdamedia.
Media type code
  • n
Other physical details
illustrations
System control number
(OCoLC)829130709

Library Locations

    • Curtis Laws Wilson LibraryBorrow it
      400 West 14th Street, Rolla, MO, 65409, US
      37.955220 -91.772210
Processing Feedback ...