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Stability of rare‐earth‐doped spherical yttria‐stabilized zirconia synthesized by ultrasonic spray pyrolysis
Author(s) -
Nafsin Nazia,
Li Hui,
Leib Elisabeth W.,
Vossmeyer Tobias,
Stroeve Pieter,
Castro Ricardo H. R.
Publication year - 2017
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/jace.14971
Subject(s) - materials science , yttria stabilized zirconia , dopant , sintering , cubic zirconia , grain growth , thermal barrier coating , doping , thermal stability , chemical engineering , grain size , ceramic , phase (matter) , composite material , thermal conductivity , crystallite , metallurgy , optoelectronics , chemistry , organic chemistry , engineering
Phase stability is one of the crucial requirements for any material that can be used at elevated temperature applications such as thermal barrier coating ( TBC ). The most traditional TBC material, partially stabilized zirconia, limits the operating temperature due to its phase transformation. Conversely, the low thermal conductivity of fully stabilized zirconia ( YSZ ) may enable effective reduction in the surface temperature on the coated component, while avoiding deleterious phase transitions, although still being subjected to sintering and grain growth. It has been reported that addition of rare‐earths as dopants to YSZ can significantly increase resistance to grain growth at high temperature. Keeping this under consideration, this work investigates the role of rare‐earths (lanthanum and gadolinium) in increasing thermal stability of YSZ microspheres, the building blocks for high‐temperature photonics for reflective TBC . The spheres were produced by ultrasonic spray pyrolysis, and the doping led to significant improvement of stability by significant inhibition of grain growth. While the individual dopants showed significant growth and sintering inhibition up to 900°C, co‐doping with 4% (in mol) of each (Gd and La) led to coarsening resistance up to 1000°C for 3 hours, when particles retained reasonable spherical features with nanometric crystallite sizes.