Factors affecting the sintering and the electrical properties of Sr-doped LaCrO3

Duvigneaud, Paul-Henri; Pilate, P.; Cambier, F.

doi:10.1016/0955-2219(94)90073-6

Cited by 20 publications

(12 citation statements)

References 7 publications

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“…The unit cell parameters of the LSC phase were determined using a least square refinement program. The typical refined unit cell parameters are: a = 5.441 (3) Å, b = 7.692 (7) Å, c = 5.451 (6) Å and V = 228.2 (3) Å 3 , which are in good agreement with the reported values of LSC [6,7].…”

Section: Sample Preparationsupporting

confidence: 74%

Structural investigations of La0.8Sr0.2CrO3 by X-ray and neutron scattering

Patra

Nair

Sastry

et al. 2009

Journal of Alloys and Compounds

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Section: Sample Preparationsupporting

confidence: 74%

Structural investigations of La0.8Sr0.2CrO3 by X-ray and neutron scattering

Patra

Nair

Sastry

et al. 2009

Journal of Alloys and Compounds

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“…19,30 The Sr 2 CrO 4 -rich phase presence in the as prepared materials was confirmed in samples with higher Sr content (x = 0.15, 0.20 and 0.25), which at higher temperatures first turns to SrCrO 4 and later forms a liquid phase to promote perovskite sintering. 20 With noticeable grain growth, the slightly decreased shape factor Y indicates that grains become diverse to ideal spheres, as already observed in the case of combustion-derived LSCM ceramics. 21 …”

Section: Resultsmentioning

confidence: 73%

“…Several routes are possible to prepare complex oxide powders, including solid-state reaction, 14 the chelating method, 15 gel casting, 16 and co-precipitation 17 . Among the various preparation techniques, combustion synthesis [18][19][20][21] enables the preparation of ultrafine soft agglomerated metal oxide powder. The secondary phase present after synthesis can be controlled by subsequent calcination.…”

Section: Introductionmentioning

confidence: 99%

Novel materials based on La0.75SrxA0.25-xCr0.5Mn0.5O3 (A=Ba, Ca, Mg) as full-ceramics anodes in high-temperature fuel cells

Skalar¹,

Marinšek²,

Zupan³

2018

Mater. Tehnol.

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Among alternative anode materials for high-temperature fuel cells, the complex ceramic oxide La0,75Sr0,25Mn0,5Cr0,5O3 (LSCM) has recently shown good catalytic activity regarding fuel oxidation and sufficient stability in reductive environments at relatively low steam-to-carbon ratios. However, the electrical and ionic conductivities of LSCM are lower compared to some other perovskite materials. One of the possibilities to improve the conductivity of LSCM is in its composition variations, i.e., altering the Sr-content, doping on the A-site of the perovskite with other ions (Ba, Ca and Mg), and varying the Mn-to-Cr ratio on the B-site of the perovskite. In this paper, systems with the general formula La0.75SrxA0.25-xCr0.5Mn0.5O3 (A = Ba, Ca, Mg, x varies between 0 and 0.25) are described. Within the investigated system, prepared materials after synthesis contain the perovskite structure as a main crystallographic phase with relatively low additions of secondary phases. Any secondary phases are undesired, because they may substantially influence the electrical properties of the final materials. In samples with relatively high Sr-additions, a secondary Sr-rich phase Sr2CrO4 is also identified. Ca-doping may result in traces of CaCr2O4 phase in as-synthesized samples, while Ba-doping may lead to BaCrO4 or BaCO3 phases with higher Ba-additions. The quantity of the secondary phases may be controlled by calcination program or sintering conditions. Secondary phases, which may form additional grains or liquid phase, also influence the development of microstructures during sintering. Within the investigated compositions, the most promising materials are La0.75SrxCa0.25-xCr0.5Mn0.5O3 (x = 0.05-0.15), because they exhibit single-phase microstructure with fine grains after sintering at 1200°C. Materials with Ba-or Mg-additions form precipitates of secondary phases at 1200°C, which also remain present after sintering at higher temperatures. Keywords: combustion synthesis, perovskite, thermal analysis, x-ray powder diffraction, quantitative microstructure analysis La0,75Sr0,25Mn0,5Cr0,5O3 (LSCM) je med alternativnimi anodnimi materiali za visokotemperaturne gorivne celice pokazal dobro katalitsko aktivnost za oksidacijo goriva ter zadovoljivo stabilnost v reduktivnih okoljih z relativno nizkim razmerjem med vodno paro in ogljikom. Vendar pa ima LSCM v primerjavi z nekaterimi drugimi perovskiti nekoliko ni`jo elektri~no in ionsko prevodnost. Ena od mo`nosti za izbolj{anje njegove prevodnosti je v variacijah sestave, npr. sprememba koncentracije Sr, dopiranje na A mestu v perovskitu z drugimi ioni (Ba, Ca in Mg), variiranje razmerja med Mn in Cr na B mestu v perovskitu. V prispevku obravnavamo sistem s splo{no formulo La0.75SrxA0.25-xCr0.5Mn0.5O3 (A = Ba, Ca, Mg, x variira med 0 in 0,25). Materiali v preiskovanem sistemu po sintezi kot glavno fazo vsebujejo perovskit z relativno nizko vsebnostjo sekundarnih faz. Kakr{nekoli sekundarne faze so neza`elene, ker lahko bistveno vplivajo na elektri~ne lastnosti kon~nih materialov. V ...

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“…At a lower Sr concentration, SrCrO 4 (according to phase diagram SrO-Cr 2 O 3 ) forms a liquid phase due to eutectic and peritectic reactions 21 that promote sintering. 22 In principle, a higher Sr-content increases the amount of SrCrO 4 phase which reacts to the liquid phase and secondary solid phase through a peritectic transformation. This secondary solid phase hinders sintering.…”

Section: Resultsmentioning

confidence: 99%

Phase and microstructure development of LSCM perovskite materials for SOFC anodes prepared by the carbonate-coprecipitation method

Zupan¹,

Marinšek²,

Skalar³

2016

Mater. Tehnol.

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Most SOFC development has been based on nickel yttria-stabilized zirconia anodes. Such materials have excellent catalytic properties for fuel oxidation, high electrical conductivity, good mechanical strength and an appropriate thermal expansion coefficient compatible with other cell components. Unfortunately, cermet anodes based on doped zirconia exhibit some disadvantages, e.g., the catalysing side reaction of carbon deposition during hydro-carbon fuel oxidation and a susceptibility to sulphur poisoning. Perovskite-type compounds based on lanthanum-strontium-manganese-chromium oxide (LSCM) can serve as an alternative material. Since the optimal perovskite composition is still not known, La1-xSrxMnyCr1.yO3±d (x from 0 to 0.3 and y from 0.4 to 0.6) ceramics were prepared with the co-precipitation method. Crystalline phase formation was followed by X-ray powder diffraction and Rietveld refinement. Quantitative microstructure analysis of the samples sintered at various temperatures was performed on SEM micrographs using Axiovision 4.8 software. Keywords: co-precipitation, oxide LSCM anode, phase development, microstructure Ve~ina razvoja visokotemperaturnih gorivnih celic je temeljila na anodnih materialih na osnovi niklja in cirkonijevega dioksida, stabiliziranega z itrijem. Ta ima odli~ne katalitske lastnosti pri reakciji oksidacije goriva, visoko elektri~no prevodnost, dobro mehansko trdnost in temperaturni razteznostni koeficient, skladen z ostalimi komponentami celice. @al so ti materiali med delovanjem podvr`eni ne`elenim reakcijam izlo~anja ogljika in zastrupljanja z`veplom, zato jih posku{amo nadomestiti z oksidnimi spojinami perovskitnega tipa, z lantan-stroncij-mangan-krom oksidom (LSCM). Optimalna sestava teh materialov {e ni znana, zato smo z metodo soobarjanja pripravili keramiko La1-xSrxMnyCr1.yO3± d (x od 0 do 0,3 in y od 0,4 do 0,6). Z rentgensko pra{kovno analizo in Rietveldovim prilagajanjem smo spremljali razvoj kristalnih faz. Z analizo SEM posnetkov vzorcev po sintranju pri razli~nih temperaturah smo mikrostrukture pripravljenih materialov kvantitativno ovrednotili z uporabo programa Axiovision 4.8.

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Factors affecting the sintering and the electrical properties of Sr-doped LaCrO3

Cited by 20 publications

References 7 publications

Structural investigations of La0.8Sr0.2CrO3 by X-ray and neutron scattering

Structural investigations of La0.8Sr0.2CrO3 by X-ray and neutron scattering

Novel materials based on La0.75SrxA0.25-xCr0.5Mn0.5O3 (A=Ba, Ca, Mg) as full-ceramics anodes in high-temperature fuel cells

Phase and microstructure development of LSCM perovskite materials for SOFC anodes prepared by the carbonate-coprecipitation method

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