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Transformation of Electron‐Beam Physical Vapor‐Deposited 8 wt% Yttria‐Stabilized Zirconia Thermal Barrier Coatings
Author(s) -
Lughi Vanni,
Clarke David R.
Publication year - 2005
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00452.x
Subject(s) - monoclinic crystal system , tetragonal crystal system , materials science , cubic zirconia , yttria stabilized zirconia , thermal barrier coating , raman spectroscopy , annealing (glass) , electron diffraction , analytical chemistry (journal) , crystallography , diffraction , chemistry , crystal structure , metallurgy , ceramic , optics , physics , chromatography
Yttria‐stabilized (8.6 mol% YO 1.5 ) zirconia thermal barrier coatings evolve at high temperatures from the “non‐transformable,” metastable tetragonal‐prime phase in their as‐deposited condition to a mixture of the tetragonal and cubic phases. The kinetics of the transformation at 1200° and 1425°C are reported based on X‐ray diffraction measurements. Complementary Raman spectroscopy measurements indicate a sharpening of the tetragonal bands at 263 and 465 cm −1 that is attributed to a systematic decrease in disorder of the Y 3+ and oxygen vacancies with annealing. No transformation to the monoclinic form of zirconia is observed immediately after high‐temperature treatment. However, partial transformation to monoclinic occurs after a prolonged time (months) at room temperature in those samples treated at 1425°C, indicating the development of isothermal martensite.