This title appears in the Scientific Report :
2009
Please use the identifier:
http://hdl.handle.net/2128/3722 in citations.
Korrosion von PCA durch Metalljodidschmelzen sowie deren Benetzungseigenschaften
Korrosion von PCA durch Metalljodidschmelzen sowie deren Benetzungseigenschaften
On high-energy discharge lamps with burners consisting of polycrystalline aluminum oxide (PCA) corrosion leads to relocation of the wall material; the extent of the phenomenon depends on the composition and the wetting behaviour of the liquid salt mixture contained in the lamp. The aim of this work...
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Personal Name(s): | Fischer, Sarah Christine (Corresponding author) |
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Contributing Institute: |
Werkstoffstruktur und Eigenschaften; IEF-2 |
Imprint: |
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
2009
|
Physical Description: |
148 S. |
Dissertation Note: |
RWTH Aachen, Diss., 2009 |
ISBN: |
978-3-89336-584-5 |
Document Type: |
Book Dissertation / PhD Thesis |
Research Program: |
Rationelle Energieumwandlung |
Series Title: |
Schriften des Forschungszentrums Jülich : Energie & Umwelt / Energy & Environment
44 |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
On high-energy discharge lamps with burners consisting of polycrystalline aluminum oxide
(PCA) corrosion leads to relocation of the wall material; the extent of the phenomenon
depends on the composition and the wetting behaviour of the liquid salt mixture contained in the lamp.
The aim of this work was to better comprehend these phenomena. For this the wetting behaviours of several iodides on PCA- and carbon plates in a water-free argon atmosphere was determined in a contact angle measurement apparatus. While pure salts show good or, at high temperatures, complete wetting, the surface wetting of binary salt mixtures is positively worse, even if only small amounts of the second component are present. From the contact angle measurements the surface tension of the pure salts could be determined.
By combining the YOUNG-LAPLACE-Equation with the BUTLER-Equation, the excess GIBBS
energy could be related to the contact angles of salt mixtures, which makes the estimation of their wetting properties possible.
The extent of the corrosion was determined by annealing experiments in a temperature
gradient. No corrosion was found in reference experiments without any salt. In addition to diverse corrosion phenomena the formation of cerium aluminate was observed in some cases.
All these effects could also be reproduced by computer simulations, for which a special
program was developed. This program may lead to the development of advanced software in
the future which can calculate the shape and corrosivity of lamp-relevant salt melts. |