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Summer 2008 Seminar
Monday, August 4, at 3:30 p.m. room 184 Watts Hall
Aysegul Aygun
PhD Candidate advised by Dr. Nitin Padture
Department of Materials Science and Engineering
The Ohio State University
Novel Thermal Barrier Coatings (TBCs) that are Resistant to High Temperature Attack by CaO-MgO-Al2O3-SiO2 (CMAS) Glassy Deposits
Abstract
Higher performance and durability requirements of gas-turbine engines will require a new generation of thermal barrier coatings (TBCs). This is particularly true of engines operated at higher temperatures, where TBCs are subjected to attack by CaO-MgO-Al2O3-SiO2 (CMAS) glassy deposits. In this work, a new approach for mitigating CMAS attack on TBCs is introduced, where up to 20 mol% Al2O3 and 5 mol% TiO2 in the form of a solid solution is incorporated into Y2O3-stabilized ZrO2 (YSZ) TBCs. The fabrication of such TBCs with engineered chemistries is made possible by the solution-precursor plasma spray (SPPS) process, which is uniquely suited for depositing coatings of metastable ceramics with extended solid-solubilities.
In this study, CMAS interactions with SPPS TBCs of various metastable compositions are compared with reference air plasma spray (APS) TBC. In this talk, results from characterization and testing of these new TBCs will be presented, together with a discussion of mechanisms responsible for the CMAS-attack mitigation.
Bio
Aysegul Aygun was born and raised in Istanbul, Turkey. She received a B.S in 1998 from Istanbul University and a M.S in 2002 from Istanbul Technical University. From 1999 to 2002, she worked as a researcher in Marmara Research Center in Kocaeli, Turkey, and as a research assistant at Istanbul Technical University after finishing her MS until 2003. In late 2003 she moved to the US and worked as a visiting scientist at University of Virginia for four months. In 2005, she joined the department of Materials Science and Engineering under the advisement of Prof. Nitin Padture, and is currently a PhD candidate. Her research has been focused on novel thermal barrier coatings that are resistant to CaO-MgO-Al2O3-SiO2 (CMAS) degradation. She was awarded a scholarship to attend and present her poster at Engineering Conference International Workshop on Thermal Barrier Coatings in Irsee, Germany, August, 2007. Her research project has also been cited on over 100 websites including Scientific American, ABC Science and Discovery Channel News.
