Preparation And Properties Of Spinel Ferrite, Manganese Material

In this paper, MnFe2O4 was prepared by co-precipitation phase inversion method and the sol-gel self-propagating combustion method, On the basis of co-precipitation phase inversion method, composite MnFe2O4 was prepared by doping and changing the molar ratio of iron and manganese ions. XRD, Thermal Analysis Technology, FT-IR, Uv-Vis, TEM and Differential Scanning Calorimetry measurement(DSC)were employed to characterize the sample.For the MnFe2O4 prepared by co-precipitation method, first we compared the precipitation calcination method and phase inversion bath in MnFe2O4 preparation. We focus on phase inversion of the water bath method, discussed the water bath temperature, aging time, reaction pH, titration methods and other factors, Then we analyzed the crystal type, particle size, temperature resistance, infrared absorption properties, ultraviolet and visible light absorption properties, catalytic properties and transformation mechanism of MnFe2O4; In sol-gel self-propagating combustion method, the preparation conditions of pH value, molar ratios of citric acid to total metals ion, and reaction time were studied. We foucued on analyzing a series of chemical reactions of self-propagating combustion products, which took place in a muffle furnace system at high temperature calcination, calcination temperature and calcination time were discussed, we analyzed the products of crystal, temperature, infrared absorption properties and catalytic performance on ammonium perchlorate(AP).The results show that the precipitation calcination method's product was the mixture of MnFe2O4, Mn2O3 and Fe2O3, while the single crystal phase MnFe2O4 could be prepared by phase inversion bath method. Through sol-gel self-propagating combustion method we could parpare MnFe2O4 particles with homogeneous distribution and about 20nm of average particle size. MnFe2O4 prepared by those two methods have same thermal stability, without significant change in the infrared absorption properties. However, the Uv-Vis absorption properties was different, the MnFe2O4 prepared by co-precipitation method have deeper dark color, samples prepaered by both of this two methods show good catalytic toward AP, but MnFe2O4 prepared by sol-gel self-propagating combustion method have better catalytic performance.By comparing co-precipitation phase inversion method and self-propagating combustion method, we knew that the products prepared by co-precipitation phase inversion have better crystallinity, we used Fe2+ replace Mn2+ and excess Mn2+ to prepare the composite MnFe2O4 materials through co-precipitation phase inversion method, We investigated the impact of Fe2+ replacing Mn2+ and excess Mn2+ to MnFe2O4 on crystal structure, temperature resistance, infrared absorption properties and Uv-Vis absorption properties. The results show that: composite MnFe2O4 still have spinel crystal structure, the lattice constant and particle size have changed, thermal stability and infrared absorption properties haven't changed, Uv-Vis absorption properties changed notably, the composite MnFe2O4 materials' color turn into deeper dark.