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Perovskite‐Type Strontium Zirconate as a New Material for Thermal Barrier Coatings
Author(s) -
Ma Wen,
Mack Daniel E.,
Vaßen Robert,
Stöver Detlev
Publication year - 2008
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.1551-2916.2008.02472.x
Subject(s) - materials science , thermal barrier coating , yttria stabilized zirconia , temperature cycling , composite material , coating , zirconate , thermal expansion , cubic zirconia , tetragonal crystal system , phase (matter) , ceramic , thermal , chemistry , titanate , physics , organic chemistry , meteorology
Perovskite‐type SrZrO 3 was investigated as an alternative to yttria‐stabilized zirconia (YSZ) material for thermal barrier coating (TBC) applications. Three phase transformations (orthorhombic↔pseudo‐tetragonal↔tetragonal↔cubic) were found only by heat capacity measurement, whereas the phase transformation from orthorhombic to pseudo‐tetragonal was found in thermal expansion measurements. The thermal expansion coefficients (TECs) of SrZrO 3 coatings were at least 4.5% larger than YSZ coatings up to 1200°C. Mechanical properties (Young's modulus, hardness, and fracture toughness) of dense SrZrO 3 showed lower Young's modulus, hardness, and comparable fracture toughness with respect to YSZ. The “steady‐state” sintering rate of a SrZrO 3 coating at 1200°C was 1.04 × 10 −9 s −1 , which was less than half that of YSZ coating at 1200°C. Plasma‐sprayed coatings were produced and characterized. Thermal cycling with a gas burner showed that at operating temperatures ∼1250°C the cycling lifetime of SrZrO 3 /YSZ double‐layer coating (DLC) was more than twice as long as SrZrO 3 coating and comparable to YSZ coating. However, at operating temperatures >1300°C, the cycling lifetime of SrZrO 3 /YSZ DLC was comparable to the optimized YSZ coating, indicating SrZrO 3 might be a promising material for TBC applications at higher temperatures compared with YSZ.