Magnetic Properties of CoFeSiB Powders, Suspensions, and in Rigid Matrix

The aim of this study is to investigate the magnetic properties of micrometric soft magnetic CoFeSiB particles as powders, in suspensions and embedded in a rigid polymer matrix. The CoFeSiB particles were obtained by milling in a planetary ball mill amorphous magnetic microwires prepared by an in-rotating-water quenching technique. The milled powder was sieved by means of a sieve shaker using a series of micrometric mesh sieves. A series of powders with particles in the following dimensional ranges were obtained: 40-63, 63-80, and 80-100 micrometers. The particles were imaged by mean of SEM that revealed that the particles had irregular shapes. Also, magnetic measurements were performed for all the powders. The powders were further used to prepare suspensions of magnetic particles in a viscous liquid carrier which are known as magnetorheological (MR) fluids. Magnetic measurements made on magnetorheological suspensions reveal that particles mobility and structuring result in increased susceptibility. Finally, we prepared samples of magnetic CoFeSiB particles embedded in a polymer rigid matrix. The particles were in the same concentration as in the case of the MR fluids. The magnetic measurements on the material thus prepared indicated that the magnetic saturation is closed to the magnetic saturation of the MR fluid but no changes in the susceptibility compared to powders were observed.