Iranian Research Organization for Science and Technology Journal of Particle Science and Technology 2423-4087 4 1 2018 06 25 Effects of Fe2O3 addition and mechanical activation on thermochemical heat storage properties of the Co3O4/CoO system 13 22 677 10.22104/jpst.2018.2799.1116 EN Nariman Nekokar Department of Metallurgy and Materials Engineering, Hamadan University of Technology, Hamadan, Iran Mehdi Pourabdoli Department of Metallurgy and Materials Engineering, Hamadan University of Technology, Hamadan, Iran Ahmad Ghaderi Hamidi Department of Metallurgy and Materials Engineering, Hamadan University of Technology, Hamadan, Iran Journal Article 2018 02 26 Effects of Fe₂O₃ addition (2-20 wt%) with 1 h mechanical activation on redox reactions of Co₃O₄ were studied by TG/DSC, SEM, and XRD analyses. The results showed that a Fe₂O₃ addition from 2 to 15 wt% increases the oxygen release from 1.4 to 3.4 wt% and decreases the reduction onset temperature from 1030 to 960 °C, while it increases the oxygen uptake value and re-oxidation onset temperature respectively from 1.5 to 3.3 wt% and from 930 to 1010 °C. The increase in iron oxide to 20 wt% resulted in loss of heat storage properties due to significant reduction in oxygen release and uptake. Moreover, TG/DSC analyses revealed that reduction enthalpy of as-received Co₃O₄, 1 h ball milled Co₃O₄, and 1 h ball milled Co₃O₄-15% Fe₂O₃ are 622, 496, and 895 kJ/kg, respectively. Phase identification and TG experiments under argon atmosphere demonstrated that Fe₂O₃ participates in the reduction process. Furthermore, adding 15 wt% of iron oxide to cobalt oxide and 1 h mechanical activation improved the redox cyclability of cobalt oxide. https://jpst.irost.ir/article_677_71a3cb155f8dc89bf3d0365288219936.pdf