Study of the structural and magnetic properties of

Authors: Diana Marcela Osorio Ospina Irvin Jadway Castro Navas German Antonio Pérez Alcázar Jesus Anselmo Tabares

Publish Date: 2011/11/23

Volume: 207, Issue: 1-3, Pages: 1-5

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Abstract

Magnetorheological MR fluids are new ironbased materials whose applications include brakes dampers clutches shock absorbers systems and polishing of optical surfaces lens and mirrors They are dependent on the size and shape of particles as the magnetic properties Interested in the possibility of using ironrich powders commonly used in nondestructive testing ranging in size from a few μm to about 200 μm and lower cost than those commercially used for MR fluids a study of the structural and magnetic properties of ironrich metallic particles by Xray diffraction XRD and Mössbauer spectroscopy MS at room temperature has been done Powders as received were separated into particle sizes smaller than 20 μm sample A and in the range of 20–38 μm sample B because these are the sizes generally required for applications in MR fluids The particles whose sizes exceed the above values were ground in a high energy planetary mill for 3 h using different values of rotational speed/time 200 rpm for one hour a pause of 10 s 140 rpm for one hour pause 10 s and then 175 rpm during the last hour These powders were sieved to obtain particles smaller than 20 μm sample C According XRD results in all samples only αFe lattice parameter a = 28672 Å and Fe2O3 lattice parameter a = 50371 Å and c = 137558 Å were present The Mössbauer spectra were fitted with two sextets The hyperfine parameters values allowed us to assign the highest relative area spectrum sextet corresponding to αFe and the second one to Fe2O3 in accord to the XRD results Thus the preparation method using mechanical milling for diminishing the size of the metallic particles allowed us to get particles with size and magnetic properties that could lead to potentially MR fluids applications

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