Milling Duration Influence on Strontium Hexaferrite Technological Characteristics

Abstract:

Fine powders of strontium hexaferrite are widely used in powder metallurgy for the production of permanent magnets resistant to atmospheric oxygen and high working temperatures. Obtaining powders with predefined technological characteristics in minimal time and with minimal energy consumption is an actual problem of powder metallurgy. The paper provides the results of experimental studies of technological characteristics of strontium hexaferrite powder (SrFe₁₂O₁₉) during milling in a beater mill. Mechanical milling of coarse strontium hexaferrite was carried out in the mill with the system of rotating beaters for 120 minutes without and with the creation of a pseudo fluidized bed. The fluidization was formed by a perpendicular constant and alternating magnetic field with induction gradients of 150 and 210 mT/m. Average particle size and powder bulk density dependencies from milling time were studied. Experimental data show that milling with the formation of a magneto fluidized bed allows intensifying the process. Beginning from 70 minutes, the dependencies of average particle size and bulk density come to almost asymptotic behavior making further milling rather ineffective. Carried out research allows choosing optimal milling duration for obtaining the required average particle size.

• Periodical: Defect and Diffusion Forum (Volume 410)
• Pages: 730-734
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.410.730
• Online since: August 2021
• Authors: Ivan N. Egorov*, Nikolay Ya. Egorov, Svetlana I. Egorova
• Keywords: Beater Mill, Bulk Density, Grain Size Distribution, Magneto Fluidized Bed, Mechanical Milling, Strontium Hexaferrite

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