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

Abstract

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 NH₃ gas flow and subsequent pyrolysis of mixtures of ferrite and (Fe₃Ni)N powders under N₂ gas flow. (Ni-Fe)/Fe₃O₄ composite powder was prepared by heating the coprecipitated powder of NiC₂O₄/FeC₂Oa=0. 5-r2. 0 (molar ratio) at 350°C for 1h in NH₃ gas, followed by heating at 500°C for 1 h in N₂ gas. It was found that the thermal stability of (Ni-Fe)/Fe₃O₄ composite powder was affected by the composition of (Ni-Fe)alloy in the composite powder.