Ferrite ceramics produce one of the strongest types of magnetics. Ferrites are ferromagnetic ceramic materials, composed primarily of iron, boron and barium, or strontium and molybdenum. A ferrite material has a high magnetic permeability, which allows it to store stronger magnetic fields than iron, and are known as ceramic magnets.
Specimen preparation of friable or brittle materials such as ferrites offer a microstructural preparation challenge. Proper microstructural preparation of these materials must maintain the structure of the Ni-Fe ferrite structure. This is accomplished by first mounting the ferrite in a castable mouunting compound such as epoxy. Initial grinding with a 320 grit or finer SiC paper is required to prevent pulling out the ferrite particles, especially the smaller particles. Rough polishing is accomplished on low napped polishing cloths using diamond, with final polishing for a very short time on a high napped cloth using an alumina suspension.
SECTIONING
Diamond wafer cutting with medium grit / low concentration diamond blades
MOUNTING
Castable mounting acrylics or epoxies
POLISHING
Abrasive/surface |
Lubricant |
Force/ sample |
Time |
320 grit SiC paper |
Water |
5 lbs |
Until plane |
1 um DIAMAT diamond on ATLANTIS polsihing pad |
SIAMAT Colloidal Silica |
10 lbs |
5 minutes |
0.05 um Nanometer alumina on NAPPAD polishing pad |
|
5 lbs |
1 minutes |
 |
Ni-Zn ferrite, 400X (B.F.), as polished condition |