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Ta 2 O 5 /Nb 2 O 5 and Y 2 O 3 Co‐doped Zirconias for Thermal Barrier Coatings
Author(s) -
Raghavan Srinivasan,
Wang Hsin,
Dinwiddie Ralph B.,
Porter Wallace D.,
Vaβen Robert,
Stöver Detlev,
Mayo Merrilea J.
Publication year - 2004
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.1551-2916.2004.00431.x
Subject(s) - thermal barrier coating , materials science , thermal conductivity , thermal expansion , cubic zirconia , tetragonal crystal system , yttria stabilized zirconia , thermal stability , analytical chemistry (journal) , phase (matter) , doping , mineralogy , coating , composite material , chemical engineering , chemistry , ceramic , optoelectronics , organic chemistry , chromatography , engineering
Zirconia doped with 3.2–4.2 mol% (6–8 wt%) yttria (3–4YSZ) is currently the material of choice for thermal barrier coating topcoats. The present study examines the ZrO 2 ‐Y 2 O 3 ‐Ta 2 O 5 /Nb 2 O 5 systems for potential alternative chemistries that would overcome the limitations of the 3–4YSZ. A rationale for choosing specific compositions based on the effect of defect chemistry on the thermal conductivity and phase stability in zirconia‐based systems is presented. The results show that it is possible to produce stable (for up to 200 h at 1000°–1500°C), single (tetragonal) or dual (tetragonal + cubic) phase chemistries that have thermal conductivity that is as low (1.8–2.8W/m K) as the 3–4YSZ, a wide range of elastic moduli (150–232 GPa), and a similar mean coefficient of thermal expansion at 1000°C. The chemistries can be plasma sprayed without change in composition or deleterious effects to phase stability. Preliminary burner rig testing results on one of the compositions are also presented.