Ferrofluids containing Ni-Fe alloy particles

Abstract

Abstract Metallic ferrofluids containing ferromagnetic Ni-Fe alloy small particles in mercury have been prepared by an electrodeposition method. The Curie temperature of the particles can be selected to be within the range 200-800°C by controlling their Ni-Fe content. The large variation of the magnetization with temperature as found at the Curie temperature is a necessary requirement for high efficiencies when the ferrofluid is used for energy conversion purposes. The facility of selecting the Curie temperature increases the versatility of the ferrofluid by extending the temperature range over which ferrofluids can be used.