DETERMINATION OF THE DEGREE OF CRYSTALLITES ORIENTATION IN PERMANENT MAGNETS BY X-RAY SCATTERING AND MAGNETIC MEASUREMENTS

摘要

Permanent magnet compounds are basically ferromagnets with uniaxial anisotropy. In different cases, the magnets are elaborated by sintering of powders previously oriented and compressed under field. The value of the remanent induction Br is directly dependent on the degree of crystallites alignment, and we present in this paper two different quantitative methods to determine it. X-ray analysis involves the comparison of the intensities of Bragg reflections, for different values of the angle of a direction [hkl] with respect to the unique crystallographic axis of the compound. Magnetic analysis involves the comparison between experimental magnetization curves and calculated ones for different statistical distributions of crystallites orientations. Both methods were applied to NdFeB and SmCo5 magnets. They reveal that the misorientation of particles in these systems leads to a reduction of the remanent induction by about 10 %.