Preparation of Metal/Ferrite Composite Powder by the Pyrolysis of Ferrous Oxalate and Nickel Oxalate Powders Derived from Coprecipitation

摘要

A new technique for preparing metal/ferrite composite powder by the pyrolysis of ferrous oxalate and nickel oxalate powders derived from coprecipitation has been proposed. The technique was carried out as follows pyrolysis of the coprecipitated powder under NH_3 gas flow and subsequent pyrolysis of mixtures of ferrite and (Fe_3Ni)N powders under N_2 gas flow. (Ni-Fe)/Fe_3O_4 composite powder was prepared by heating the coprecipitated powder of NiC_2O_4/FeC_2O_4=0.5 approx 2.0 (molar ratio) at 350 deg C for 1h in NH_3 gas, followed by heating at 500 deg C for 1h in N_2 gas. It was found that the thermal stability of (Ni-Fe)/Fe_3O_4 composite powder was affected by the composition of (Ni-Fe)alloy in the composite powder.