Pekor, Christopher Michael
(2010)
THE EFFECT OF WATER-SOLUBLE POLYMERS ON THE MICROSTRUCTURE AND PROPERTIES OF FREEZE-CAST ALUMINA CERAMICS.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Porous ceramics can be divided into three separate classes based on their pore size: microporous ceramics with pores less than 2 nm, mesoporous ceramics with pores in the range of 2-50 nm and macroporous ceramics with pores that are greater than 50 nm. In particular, macroporous ceramics are used in a variety of applications such as refractories, molten metal filtration, diesel particulate filters, heterogeneous catalyst supports and biomedical scaffolds.Freeze casting is a novel method used to create macroporous ceramics. In this method growing ice crystals act as a template for the pores and are solidified, often directionally, through a ceramic dispersion and removed from the green body through a freeze drying procedure. This method has attracted some attention over the past few years due to its relative simplicity, flexibility and environmental friendliness. On top of this freeze casting is capable of producing materials with high pore volume fractions, which is an advantage over processing by packing and necking of particles, where the pore volume fraction is typically less than 50%. Many of the basic processing variables that affect the freeze cast microstructure, such as the temperature gradient, interfacial velocity and solid loading of the dispersion have been well established in the literature. On the other hand, areas such as the effect of additives on the microstructure and mechanical properties have not been covered in great detail.In this study the concept of constitutional supercooling from basic solidification theory is used to explain the effects of two water-soluble polymers, polyethylene glycol and polyvinyl alcohol, on the microstructure of freeze cast alumina ceramics. In addition, changes in the observed microstructure will be related to experimentally determined values of permeability and compressive strength.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
| Creators | Email | Pitt Username | ORCID  |
|---|
| Pekor, Christopher Michael | cmpst45@pitt.edu | CMPST45 | |
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| ETD Committee: |
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| Date: |
25 June 2010 |
| Date Type: |
Completion |
| Defense Date: |
26 March 2010 |
| Approval Date: |
25 June 2010 |
| Submission Date: |
31 March 2010 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Materials Science and Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
alumina; freeze casting; ice; microstructure; directional solidification; polyethylene glycol |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-03312010-025226/, etd-03312010-025226 |
| Date Deposited: |
10 Nov 2011 19:33 |
| Last Modified: |
15 Nov 2016 13:38 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/6676 |
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