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Effects of anion and synthesis route on the structure of (La0.9 Sr0.1) (Cr0.85 Fe0.05 Co0.05 Ni0.05)O3−δ perovskite and removal of impurity phases

“…6 for NY and AY, were also similar to the cell volume versus route plots of NY and AY, respectively. The volume contraction of NY and AY relative to LaCrO 3 is similar to those observed earlier for several LaCrO 3 based doped and co-doped systems [2,11,12,[14][15][16][17] as well as [30,31]. The volume contraction phenomenon was successfully explained using the concept of valence states of cations, which has been discussed below for the present system.…”

“…For an excellent review on the subject, go through the references, [1][2][3][4]. In efforts to achieve high air sinterability and electrical conductivity with highly surface reactive, ultrafine powders, several LaCrO 3 perovskites doped with cations into La-and/or Cr-sites have been synthesized by various methods-these include solid state reaction [5][6][7][8], combustion [9][10][11], polymeric gel [12,13], Pechini [14,15], and drippyrolysis [16][17][18]. Substitution of La 3+ by 0.1-0.2 mole of Sr 2+ is found to be the most suitable approach in terms of a combined effect of sintering, electrical, thermal and mechanical properties in oxidizing and reducing atmospheres [2][3][4]6].…”

“…Doping of a cationic species, e.g. Fe 2+ , Co 2+ , and Ni 2+ with a concentration of 0.05-0.2 mole in the Cr-site largely improved the conductivity and bulk density of La 1 − x Sr x CrO 3 (x = 0-0.15 mole) [2][3][4]8,11,14,15]. It was observed that Co 2+ -and Ni 2+ -doping slightly increased and decreased the CTE of La 0.85 Sr 0.15 CrO 3 , respectively [8].…”

“…Pure LaCrO 3 exhibits orthorhombic symmetry at room temperature and transforms to rhombohedral symmetry at ∼255°C [2,5]. However, doping of a metal cation in La-and/or Cr-sites of LaCrO 3 arrests either of orthorhombic and rhombohedral structures, or both at room temperature depending on the dopant, doping concentration, preparative method, and sintering temperature [2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Impurity phases, namely SrCrO 4 , La 2 O 3 , La 2 CrO 6 , etc., also exist along with the perovskite phase [6,9,10,[13][14][15][16][17][18].…”

Cromito de lantânio: material para interconectores de células a combustível de óxido sólido - uma revisão

“…Toda a água do sistema é evaporada, em baixa temperatura (110 °C) até o ponto de gel, onde é então submetido à calcinação [115], este método de obtenção é muito semelhante ao método da hidrazina, diferindo, porém nos reagentes empregados [116]. O cromito de lantânio pode ainda ser obtido por spray pirólise [117].…”