Coercive Force of Precipitation Alloys

Cunico, Cunife, and the various types of Alnico are structurally analogous in that at the state of high coercive force the crystal structure of the precipitate is distorted from a cubic lattice to a tetragonal lattice. A single empirical relation has been derived from the data for these types of materials in which maximum coercive force is directly related to degree of tetragonality and saturation induction of the precipitate. On the basis of the fine particle theory this result suggests that not only shape anisotropy but also crystal anistropy, as affected by strain, contributes to the coercive force. This work represents the first successful attempt to correlate the coercive force of the various commercial permanent magnet alloys with more fundamental characteristics.