Stability of α-Alumina Photonic Structures Formed at Low Temperatures Utilizing Chromia-Seeding

Start Page
177
End Page
186
Citation
Ceramic for Energy Conversion, Storage, and Distribution Systems (256): 177-186 (2016-05-31)
Publisher DOI
10.1002/9781119234593.ch18
Scopus ID
2-s2.0-85019623913
Emerging applications of ordered, macroporous oxide photonic structures for thermal barrier coatings, structural coloration, and thermophotovoltaics requires the stability of these features at operating temperatures. However, in high-temperature environments (>1000 °C), these structures can exhibit significant undesired microstructural changes (phase changes, sintering, grain growth, etc.) that result in a loss of the desired properties. An approach for lowering the formation temperature of α-alumina in such structures was demonstrated by seeding with chromia by secondary infiltration from precursor solutions. Seeds of α-chromia, which formed at 500 °C, successfully lowered the α-alumina formation temperature from 1200 to 800 °C by heterogeneous nucleation. Upon heating to 1200 °C, these chromia-seeds went into solid-solution with the alumina structure. However, in contrast to unseeded structures, the resulting microstructures were prone to grain growth and loss of photonic properties upon heating at 1400 °C.
Subjects
Heterogeneous nucleation
Photonic properties
Photonic structures
Precursor solutions
α-alumina
α-chromia