This title appears in the Scientific Report :
2020
Please use the identifier:
http://dx.doi.org/10.1111/jace.16932 in citations.
Please use the identifier: http://hdl.handle.net/2128/26468 in citations.
Hot‐pressing platelet alumina to transparency
Hot‐pressing platelet alumina to transparency
Alumina powder with a platelet morphology was hot‐pressed to transparency with preload pressures of 0‐8 MPa, maximum temperatures of 1750‐1825°C, maximum pressures of 2.5‐80 MPa, and isothermal hold times of 1‐7 hours. Optical transmission (in‐line and total), as well as optical losses (backward/for...
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Personal Name(s): | Schlup, Andrew P. (Corresponding author) |
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Costakis, William J. / Rheinheimer, Wolfgang / Trice, Rodney W. / Youngblood, Jeffrey P. | |
Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEK-1 |
Published in: | Journal of the American Ceramic Society, 103 (2020) 4, S. 2587 - 2601 |
Imprint: |
Westerville, Ohio
Soc.
2020
|
DOI: |
10.1111/jace.16932 |
Document Type: |
Journal Article |
Research Program: |
ohne Topic |
Link: |
Get full text Published on 2019-11-27. Available in OpenAccess from 2020-11-27. |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/26468 in citations.
Alumina powder with a platelet morphology was hot‐pressed to transparency with preload pressures of 0‐8 MPa, maximum temperatures of 1750‐1825°C, maximum pressures of 2.5‐80 MPa, and isothermal hold times of 1‐7 hours. Optical transmission (in‐line and total), as well as optical losses (backward/forward scattering and absorption), of the hot‐pressed samples were measured and related to the microstructure. Higher hot‐pressing temperatures increase the in‐line transmission. A gray discoloration of the samples (indicative of high absorption) was minimized by heat treating the powder in air prior to hot pressing and reducing the preload pressure. Maximum pressures above/below 10 MPa increased porosity, which decreased in‐line transmission and increased backward/forward scattering. Lower densities at higher pressures are attributed to a pore‐swelling phenomenon. Increasing isothermal hold time decreased porosity, which increased in‐line transmission and reduced backward/forward scattering. Best optical properties with an in‐line transmission of 65.3% at 645 nm (0.8 mm thick) were achieved by hot‐pressing heat‐treated platelet alumina powder with a preload pressure of 0 MPa, maximum temperature of 1800°C, maximum pressure of 10 MPa, and an isothermal hold time of 7 hours. This high in‐line transmission, despite its large grain size (65 µm), is attributed to crystallographic orientation of the platelets during hot pressing. |