Accession Number:

AD0021995

Title:

PERMANENT MAGNET MATERIALS

Descriptive Note:

Quarterly progress rept. no. 8, 1 Oct-31 Dec 1952

Corporate Author:

FRANKLIN INST PHILADELPHIA PA LABS FOR RESEARCH AND DEVELOPMENT

Personal Author(s):

Report Date:

1952-12-31

Pagination or Media Count:

49.0

Abstract:

An experimental comparison was made of the particle sizes of single domain ferromagnetic powders by means of methods based on the electron microscope, the broadening of x-ray diffraction lines, and the measurement of surface areas with nitrogen adsorption. The powders studied included 5-u particle size GAF General Aniline and Film Corp HP, 2-micron GAF p-818, 600-A Fe-8, 400-A Fe-7, 400-A Hyflux, 250-A NOL-1, 200-A NOL-2, and 200-A Ugine. Reasonably good agreement was obtained between the x-ray diffraction method and the electron microscope method. However, the nitrogen adsorption sizes were always higher. The results indicated that the electron microscope can be used to determine reliable particle size distributions of metallic single-domain powders provided that sufficient care is taken to produce good dispersions. In the case of single-domain ferromagnetic particles, the dispersions may be obtained by magnetic means. The electron microscope distributions must be compared to the average sizes obtained from 1 or 2 independent methods.

Subject Categories:

  • Electricity and Magnetism
  • Recording and Playback Devices
  • Magnetic and Electric Field Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE