Combustion synthesis of Ni-Zn ferrite by using glycine and metal nitrates-investigations of precursor homogeneity, product reproducibility, and reaction mechanism

In this study, Ni-Zn ferrite with the chemical formula of Ni0.5Zn0.5Fe2O4 was synthesized in an amount of 100 g per batch by means of a modified combustion synthesis method using glycine and metal (Ni, Zn, and Fe) nitrates as reactants. By directly mixing and thoroughly dehydrating, a flammable precursor with good homogeneity can be obtained. Once ignited in the air at room temperature, it underwent a combustion process, and with a large amount of gas smoke, a voluminous loose product was yielded. The as-synthesized powders were characterized by X-ray diffraction (XRD) analysis, inductively coupled plasma-atomic emission spectrometer (ICP-AES), vibrating sample magnetometer (VSM) and surface area measurements. The results revealed that the nanocrystalline Ni-Zn ferrite powders were directly formed after combustion and that the products' properties showed good reproducibility. The thermal decomposition and combustion process of the precursor were investigated using thermalgravity (TG), differential scanning calorimetry (DSC), mass spectrometry (MS) techniques simultaneously. Based on the experimental results of thermal analysis and escaping gas analysis, a possible reaction mechanism as well as a suggestion for improving the method was thus proposed.