TEMPERATURE DEPENDENCE OF THE PHYSICAL PROPERTIES OF MAGNETIC FLUIDS.

This paper reports an experimental study of the temperature dependence of the viscosity and thermal conductivity of magnetic fluids based on kerosene, VM-1 vacuum pump oil and transformer oil. All the liquids contained colloidal particles of magnetite obtained under identical conditions by coprecipitation of bi- and trivalent iron salts in an excess of ammonia. Subsequently the magnetite was peptized in oleic acid to create a concentrate of magnetic fluid. These studies show that the temperature variations in the properties of magnetic fluids are associated with the concentration of the solid phase and that this must be taken into account in thermophysical calculations, particularly in the case of concentrated fluids.