An anomalous behaviour in the phase stability of the system Fe2O3 and NiO
An anomalous behaviour in the phase stability of the system Fe2O3 and NiO
复制标题
Fe2O3 和 NiO 体系相稳定性的反常行为
DOI：
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发表时间：
1994
影响因子：
4.5
通讯作者：
V. Rao
中科院分区：
文献类型：
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作者：
S. Rajendran;V. Rao
通过烧制相应的共沉淀水合氧化物制备了含有高达 50 mol% NiO 的铁镍混合氧化物；通过 X 射线衍射、红外光谱、磁化率、电导率和热电功率测量进行表征。当含有 20 mol% NiO 的样品在 1050°C 下烧结时，形成非化学计量铁素体相。该相的电导率比 Fe2O3 或化学计量铁氧体 (NiFe2O4) 高两到三倍。该相的热电势表明载流子在 350°C 附近从 n 型急剧转变为 p 型。这种非化学计量铁素体相仅在很小的温度范围内稳定，并在 1200°C 以上解离成 α-Fe2O3 和化学计量铁素体。当在 1050°C 下烧结时，含有 5 mol% 和 10 mol% NiO 的样品也含有少量这种非化学计量铁素体相。
Iron-nickel mixed oxides containing up to 50 mol% of NiO were prepared by firing the corresponding co-precipitated hydrous oxides; characterization was performed by X-ray diffraction, infrared spectroscopy, magnetic susceptibility, electrical conductivity and thermoelectric power measurements. A non-stoichiometric ferrite phase was formed when a sample containing 20 mol% NiO was sintered at 1050°C. This phase had two- to three-fold higher conductivity than either Fe2O3 or the stoichiometric ferrite (NiFe2O4). The thermoelectric power of this phase indicated a sharp change of charge carriers from n- to p-type near 350°C. This non-stoichiometric ferrite phase was stable only in a small temperature range and dissociated into α-Fe2O3 and stoichiometric ferrite above 1200°C. Samples containing 5 and 10 mol% NiO also had small fractions of this non-stoichiometric ferrite phase when sintered at 1050°C.