Study on Interfacial Phenomena of Magnetic Fluids

The interfacial phenomena of magnetic fluids subjected to a normal magnetic field are studied experimentally. To begin with, the effect of the shape and the dimension of the transparent containers on the interfacial phenomena is examined for two kinds of magnetic fluids, ferricolloid W-40 and ferricolloid HC-50. The cross-sectional shape of the container is made to be circular, square and hexagon. The dimension of the container is set to 55mm, 70mm and 85mm. The critical magnetic induction values B_c calculated on the basis of the present expriment are compared with those obtained from the theoretical analysis by Cowley & Rosensweig, where at these values of B_c the interfacial phenomena begin to be built up. Finally, on the hysteresis in generating the transition between three kinds of deformation modes on the interface, the present observation results are compared with those obtained from the analysis by A. Gailitis. It was concluded that the shape and the dimension of the containers had no effect on the interfacial phenomena, and the critical value B_c caluculated by measured data agreed with that of the theoretical analysis. And also, the mechanism of the hysteresis was clarified mathematically in the manner of the analysis by Gailits.