Solution Combustion Synthesis and Kinetic Measurements in Ni(NO3)2–C6H8O7 System. Preparation of Nickel Powder

Solution combustion synthesis (SCS) is a widely used method to prepare nanomaterials tailored for specific applications, with a primary focus on understanding the influence of precursors on material properties and microstructure evolution. There is also a lack of systematic studies to understand the kinetics of SCS reactions. This work reports on the preparation of pure nickel by the combustion of Ni(NO₃)₂ + citric acid (C₆H₈O₇) solution and the investigation of SCS reaction mechanism by thermal analysis technique. The lower and upper combustion limits were determined depending on the citric acid to Ni(NO₃)₂ ratio. The optimal composition of the initial mixture was revealed to prepare nickel powder without using an additional post–synthesis reduction of metal oxides. Ozawa’s method was employed to calculate the effective activation energy (∼101 ± 5 kJ mol^–1) of the nickel formation reaction based on the TGA data. The magnetization of the nickel powder agglomerates with ∼80–200-nm nanoscale particles was measured to be 55.1 Am² kg^–1.