International Journal of Self-Propagating High-Temperature Synthesis. Vol. 30, No. 3, Pages 170-174, 2021

V. D. Zhuravlev^a^, *, A. V. Dmitriev^a, E. V. Vladimirova^a, I. M. Giniyatullin^a, D. I. Pereverzev^a, and E. A. Sherstobitova^b

^aInstitute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, Yekaterinburg, 620990 Russia

^bMikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences, Yekaterinburg, 620108 Russia

Abstract—Solution-combustion synthesis of Ni_xCo_3 – xO₄ (x < 1) spinels from aqueous solutions of nickel and cobalt nitrates using citric acid–glycine mixtures as a dual fuel was investigated by XRD and SEM. A decrease in combustion temperature at minimal amounts of glycine (φ_gl = 0.5) and citric acid (φ_citr = 0.2–0.3) afforded for the synthesis of NiCo₂O₄ spinel after heat treatment of as-synthesized powders at 400°C for 20 h. An increase in the fuel content of starting solutions (for Σφ = φ_gl + φ_gl > 0.9) led to an increase in reaction temperature and the formation (after annealing at 400°C) of non-stoichiometric spinels Ni_xCo_3 – xO₄ (x < 1) with an admixture of double oxides Ni_yCo_1 – yO (y = 0.71–0.77).

Keywords: SHS, solution-combustion synthesis, glycine–citric acid as a fuel, Ni_xCo_3 – xO₄ (x < 1) spinels

Off-Stoichiometric NixCo3 – xO4 (x < 1) Spinels by Solution-Combustion Synthesis Using Citric Acid–Glycine Mixtures as a Dual Fuel

Off-Stoichiometric Ni_xCo_{3 –} _xO₄ (x < 1) Spinels by Solution-Combustion Synthesis Using Citric Acid–Glycine Mixtures as a Dual Fuel