Thermochemical studies on SrFe12O19(s)

摘要: Abstract The citrate–nitrate gel combustion route was used to prepare SrFe12O19(s) powder sample and the compound characterized by X-ray diffraction analysis. A solid-state electrochemical cell of type: (−)Pt, O2(g)/{CaO(s) + CaF2(s)}//CaF2(s)//{SrFe12O19(s) + SrF2(s) + Fe2O3(s)}/O2(g), Pt(+) for measurement emf as a function temperature from 984 1151 K. standard molar Gibbs energy formation calculated data is given by: Δ f G m ∘ (SrFe12O19, s, T)/kJ mol−1 (±1.3) = −5453.5 + 1.5267 × (T/K). Standard heat capacity determined in two different ranges 130–325 K 310–820 K using flux type differential scanning calorimeter (DSC). anomaly observed at 732 K, which has been attributed magnetic order–disorder transition ferrimagnetic state paramagnetic state. enthalpy formation, H (298.15 K) entropy, S were second law method values are −5545.2 kJ mol−1 633.1 J K−1 mol−1, respectively.