High-Temperature Photonic Structures. Thermal Barrier Coatings, Infrared Sources and Other Applications

Shklover, Valery; Braginsky, Leonid; Witz, G.; Mishrikey, Matthew; Hafner, Christian

doi:10.1166/jctn.2008.2532

Cited by 50 publications

(41 citation statements)

References 4 publications

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“…While further research is required to assess their long-term performance, these particles constitute promising building blocks for the development of novel photonic coatings considered for energy systems and heat management, such as emitters/absorbers used in thermophotovoltaics [ 7 ] and refl ective TBCs. [4][5][6] …”

Section: Resultsmentioning

confidence: 99%

“…) [ 5,14 ] and Gd 2 Zr 2 O 7 (10.4 × 10 −6 K −1 ), [ 26,38 ] in contrast to La 2 Zr 2 O 7 (9.1-9.7 × 10 −6 K −1 ) [ 14 ] which has a greater deviation. Grain sizes of the Gd-doped samples are represented in Figure 5 b.…”

Section: Stability Of Gd-doped Microparticlesmentioning

confidence: 90%

“…This fi nding can possibly be attributed to a mismatch in thermal expansion coeffi cient between La 2 Zr 2 O 7 (9.1-9.7 × 10 −6 K −1 ) and ZrO 2 /YSZ (10.3 × 10 −6 K −1 , 10.5-11.5 × 10 −6 K −1 ). [ 5,14 ] After further heating to 1500 °C, all samples displayed texturing of the monoclinic phase with respect to the (002) refl ex. Additionally, the pyrochlore phase was no longer observed for samples La2.0 and La3.0.…”

Section: Stability Of La-doped Microparticlesmentioning

confidence: 99%

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High‐Temperature Stable Zirconia Particles Doped with Yttrium, Lanthanum, and Gadolinium

Leib

Pasquarelli

Blankenburg

et al. 2016

Part. Part. Syst. Charact.

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645wileyonlinelibrary.com www.particle-journal.com www. MaterialsViews.com Zirconia microspheres synthesized by a wet-chemical sol-gel process are promising building blocks for various photonic applications considered for heat management and energy systems, including highly effi cient refl ective thermal barrier coatings and absorbers/emitters used in thermophotovoltaic systems. As previously shown, pure zirconia microparticles deteriorate at working temperatures of ≥1000 °C. While the addition of yttrium as a dopant has been shown to improve their phase stability, pronounced grain growth at temperatures of ≥1000 °C compromises the photonic structure of the assembled microspheres. Here, a new approach for the fabrication of highly stable ceramic microparticles by doping with lanthanum, gadolinium, and a combination of those with yttrium is introduced. The morphological changes of the particles are monitored by scanning electron microscopy, ex situ X-ray diffraction (XRD), and in situ high-energy XRD as a function of dopant concentration up to 1500 °C. While the addition of lanthanum or gadolinium has a strong grain growth attenuating effect, it alone is insuffi cient to avoid a destructive tetragonal-to-monoclinic phase transformation occurring after heating to >850 °C. However, combining lanthanum or gadolinium with yttrium leads to particles with both effi cient phase stabilization and attenuated grain growth. Thus, ceramic microspheres are yielded that remain extremely stable after heating to 1200 °C.

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Section: Resultsmentioning

confidence: 99%

Section: Stability Of Gd-doped Microparticlesmentioning

confidence: 90%

Section: Stability Of La-doped Microparticlesmentioning

confidence: 99%

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High‐Temperature Stable Zirconia Particles Doped with Yttrium, Lanthanum, and Gadolinium

Leib

Pasquarelli

Blankenburg

et al. 2016

Part. Part. Syst. Charact.

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“…Zirconia microspheres have been recently proposed as base materials for thermal barrier coatings (TBCs) as they combine low thermal conductivity and an associated reflection of thermal radiation [1][2][3]. This reflection results from the resonant behavior of the spheres that creates discrete light states where every sphere acts as a meta-atom for light [3].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of porous yttria-stabilized zirconia microspheres by ultrasonic spray pyrolysis

et al. 2017

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A B S T R A C THigh yield synthesis of yttria-stabilized zirconia (YSZ) porous microspheres can enable application in advanced thermal barrier coatings, exploiting reflective properties originated from high temperature photonics. The complexity of typical wet-chemistry processes utilized in microspheres manufacturing limits yield and can hardly deliver stable porous structures. Here, ultrasonic spray pyrolysis was utilized to produce high quantities of porous YSZ. Droplets of an aqueous precursor solution were dragged with continuous air flow into a furnace kept at temperatures varying from 700 to 1200°C. Spherical fully cubic zirconia particles were obtained in all processing conditions, and the sizes of the spheres decreased as a function of the processing temperature, ranging from 484 to 373 nm (average diameters), while their crystallite sizes had an inverse trend, ranging from 4.9 to 25.2 nm. This was attributed to higher temperatures activating coarsening of the spheres.

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“…Practical applications for photonic crystals (PhCs) are vast [1,2]. The optical response of PhCs can be effectively controlled via structural design.…”

Section: Introductionmentioning

confidence: 99%

Potential of glassy carbon and silicon carbide photonic structures as electromagnetic radiation shields for atmospheric re-entry

et al. 2012

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During high-velocity atmospheric entries, space vehicles can be exposed to strong electromagnetic radiation from ionized gas in the shock layer. Glassy carbon (GC) and silicon carbide (SiC) are candidate thermal protection materials due to their high melting point and also their good thermal and mechanical properties. Based on data from shock tube experiments, a significant fraction of radiation at hypersonic entry conditions is in the frequency range from 215 to 415 THz. We propose and analyze SiC and GC photonic structures to increase the reflection of radiation in that range. For this purpose, we performed numerical optimizations of various structures using an evolutionary strategy. Among the considered structures are layered, porous, woodpile, inverse opal and guided-mode resonance structures. In order to estimate the impact of fabrication inaccuracies, the sensitivity of the reflectivity to structural imperfections is analyzed. We estimate that the reflectivity of GC photonic structures is limited to 38% in the aforementioned range, due to material absorption. However, GC material can be effective for photonic reflection of individual, strong spectral line. SiC on the other hand can be used to design a good reflector for the entire frequency range.

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High-Temperature Photonic Structures. Thermal Barrier Coatings, Infrared Sources and Other Applications

Cited by 50 publications

References 4 publications

High‐Temperature Stable Zirconia Particles Doped with Yttrium, Lanthanum, and Gadolinium

High‐Temperature Stable Zirconia Particles Doped with Yttrium, Lanthanum, and Gadolinium

Synthesis of porous yttria-stabilized zirconia microspheres by ultrasonic spray pyrolysis

Potential of glassy carbon and silicon carbide photonic structures as electromagnetic radiation shields for atmospheric re-entry

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