BISMANOL PERMANENT MAGNETS, EVALUATION AND PROCESSING
NAVAL ORDNANCE LAB WHITE OAK MD
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Bismanol permanent magnets were evaluated for stability under various operating conditions. The magnets, after low-temperature stabilization, exhibited a magnetic flux constancy over a wide temperature range with some loss in original energy. The magnets were stable magnetically to shock, vibration, centrifugal force and stray magnetic fields. The application of a protective coating was recommended to prevent corrosion in atmospheres of high RH. The processing techniques for bismanol magnets were improved by eliminating magnetic separation. Excess bismuth is separated from the melt by hot-pressing prior to pulverization. Bismanol magnets were made with maximum energy products up to 5.3 x 10 to the power of 6 gauss-oersteds. Present maximum value for the coercive force is 3650 oersteds and 4800 gauss for the residual flux density. Various types of pulverizing equipment were also evaluated with respect to the magnetic properties of the resulting compacts. Methods are discussed for determining percentage purity Mn-Bi content, alignment, and effective particle size in bismanol magnets.
- Electricity and Magnetism