VISCOSITY, RESISTIVITY AND SURFACE-TENSION MEASUREMENTS OF FE3O4 FERROFLUID

The viscosity eta of Fe3O4 ferrofluid at volume concentrations in the range epsilon = 0.0-0.013 are measured. The corresponding range of values of eta is 1.6-1.8 cp. A linear relationship exists between the relative viscosity and the concentration of the fluid. Measurements of relative resistivity of Fe3O4 ferrofluid at various concentrations (epsilon = 0.00526-0.0526) are also reported. The relative resistivity is taken with respect to the resistivity of the highest value of concentration available (epsilon = 0.0526) which is 2.05 X 10(6) OMEGA-m. The results show that the relative resistivity is inversely proportional to the concentration of the fluid. The variation of the resistivity with applied magnetic field is also presented. Measurements of the surface tension of Fe3O4 ferrofluid show a continuous increase with increasing concentration and have values ranging from 25.0 to 26.63 dyn/cm in the concentration range epsilon = 0.0-0.0526.