Metastable-stable phase diagrams in the zirconia-containing systems utilized in solid-oxide fuel cell application

Yashima, Masatomo; Kakihana, Masato; Yoshimura, Masahiro

doi:10.1016/0167-2738(96)00386-4

Cited by 333 publications

(224 citation statements)

References 91 publications

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“…Yashima et al, 45 on the other hand, took a closer look at the low-yttria content region (up to around 20 mol% Y 2 O 3 ). They found it impossible to reach thermodynamic equilibrium below 1200…”

Section: -6mentioning

confidence: 99%

From zirconia to yttria: Sampling the YSZ phase diagram using sputter-deposited thin films

et al. 2016

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Yttria-stabilized zirconia (YSZ) thin films with varying composition between 3 mol% and 40 mol% have been prepared by direct-current ion beam sputtering at a substrate temperature of 300 °C, with ideal transfer of the stoichiometry from the target to the thin film and a high degree of homogeneity, as determined by X-ray photoelectron and energy-dispersive X-ray spectroscopy. The films were analyzed using transmission electron microscopy, revealing that, while the films with 8 mol% and 20 mol% yttria retain their crystal structure from the bulk compound (tetragonal and cubic, respectively), those with 3 mol% and 40 mol% Y2O3 undergo a phase transition upon sputtering (from a tetragonal/monoclinic mixture to purely tetragonal YSZ, and from a rhombohedral structure to a cubic one, respectively). Selected area electron diffraction shows a strong texturing for the three samples with lower yttria-content, while the one with 40 mol% Y2O3 is fully disordered, owing to the phase transition. Additionally, AFM topology images show somewhat similar structures up to 20 mol% yttria, while the specimen with the highest amount of dopant features a lower roughness. In order to facilitate the discussion of the phases present for each sample, a thorough review of previously published phase diagrams is presented.

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Section: -6mentioning

confidence: 99%

From zirconia to yttria: Sampling the YSZ phase diagram using sputter-deposited thin films

et al. 2016

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“…The 11.1 YSZ bulk structure falls within the metastable, kinetically-stablized, non-transformable t ' region of the ZrO2 − YO1.5 phase diagram (Yashima, 1996). The most favorable atomic model of this phase has a P-4m2 tetragonal structure with pairs of Y ions substituted in a tetrahedral arrangement in the Zr sublattice of the ZrO2 P42/nmc phase and 1 O vacancy formed for each doped Y pair in the next nearest O neighbor position (Eichler, 2001).…”

Section: /79mentioning

confidence: 99%

Experimental Demonstration of Advanced Palladium Membrane Separators for Central High Purity Hydrogen Production

Emerson¹,

Magdefrau²,

Opalka³

et al. 2010

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“…Nesta Figura todos os picos apresentaram predominantes picos da fase cúbica, tipo fluorita, indexados pelo padrão JCPDS # 82-1246. É importante frisar que há autores [19][20] que atribuem estes picos identificados a uma pseudofase cúbica, que é formada de uma fase metaestável tetragonal, cuja identificação por DRX não seria possível, mas sua condutividade elétrica é menor que do sistema cúbico [17][18][19][20]. Através do calculo da razão dos parâmetros de rede c/a pelo programa FULLPROF verificou-se que os mesmos tendem para a unidade, o que corrobora com os dados da literatura [17][18][19][20], reforçando a suposição de que a rede está tendendo à estabilização total na forma cúbica.…”

Section: Caracterização Estruturalunclassified

Deposição de filmes de ZEI 8% em mol por sistema de spray pirólise modificado

Toniato

2008

Matéria (Rio J.)

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RESUMONeste trabalho, foram produzidos filmes de zircônia estabilizada com ítria com 8 % em mol (ZEI), que podem aplicados como eletrólitos para pilhas a combustível de óxido sólido (PaCOS), abrasivos e proteção anti-corrosiva, depositados em substrato de quartzo pela técnica de spray pirólise e tratados termicamente a 1000ºC. Para obtenção dos filmes, foi utilizado um sistema de deposição por spray-pirólise modificado segundo patente depositada no INPI, que se comparado ao sistema tradicional onde o bico atomizador fica estático durante o processo de deposição, resulta na produção de filmes de melhor homogeneidade, rugosidade e na redução dos defeitos morfológicos, como as trincas e fissuras. As melhorias no aparelho de deposição forneceram, também, melhor controle sobre os parâmetros de deposição quando comparado ao sistema tradicional, como a taxa e temperatura de deposição. A estrutura do filme foi analisada através de difração de raios X, que se apresentaram policristalinos e de acordo com a identificação realizada com o padrão JCPDS # 821246, os filmes de YSZ estão arranjados em uma estrutura cúbica de face centrada do tipo fluorita, e com orientação preferencial dos grãos no plano (111). A morfologia dos filmes foi analisada por imagens de microscopia ótica e microscopia de força atômica, sendo comparada às trincas, a rugosidade e distribuição de grãos, para os filmes após o tratamento térmico. Os melhores resultados foram obtidos para os filmes depositados pelo método de spray pirólise modificado quando comparado ao sistema tradicional. Palavras-chaves: ZEI, eletrólitos, PaCOS e MESP®. Deposition of YSZ 8 mol% films by modified spray pyrolysis system ABSTRACTIn this work zirconia stabilized with itria films 8 mol% (8YSZ) had been produced, applied as electrolytes for solid oxide fuel cell (SOFC), deposited in quartz substrate spray-pyrolysis technique and treated at 1000ºC. For attainment of films a system deposition for spray-pyrolysis modified according to patent deposited in INPI was used, that if compared with traditional system where atomized is static during deposition process, results in production of films more homogeneous, roughness and reduction of morphologic defects, at cracks. The improvements in deposition apparatus had also supplied better control of deposition parameters when compared with traditional system, with solution flow rate and temperature of deposition. The structure of films had been analyzed through X-ray diffractometry (XRD) results indicated that polycrystals films, structure cubical centered face of fluorite type with preferential orientation of grains in plan (111) identification through of standard JCPDS # 821246. The films morphology was analyzed by optical microscopy and atomic force microscopy, being compared cracks, roughness and distribution of grains, for films after thermal treatment. The results indicate that the use deposited in modified method of spray-pyrolysis (MESP®) appropriate deposited films the deposited were dense, crack-free and well adhered to the subs...

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Metastable-stable phase diagrams in the zirconia-containing systems utilized in solid-oxide fuel cell application

Cited by 333 publications

References 91 publications

From zirconia to yttria: Sampling the YSZ phase diagram using sputter-deposited thin films

From zirconia to yttria: Sampling the YSZ phase diagram using sputter-deposited thin films

Experimental Demonstration of Advanced Palladium Membrane Separators for Central High Purity Hydrogen Production

Deposição de filmes de ZEI 8% em mol por sistema de spray pirólise modificado

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