Processing of alnico permanent magnets by advanced directional solidification methods

Thick-film permanent magnets by membrane electrodeposition

Thick films of nearly equiatomic Co–Pt produced by electrodeposition into nanoporous membranes exhibit an isotropic magnetic phase with square hysteresis loops sMr /Ms=0.95d and coercivity of up to 1.3 T. The initial magnetization curve is characteristic of pinning-type magnets. The coercivity can be controlled by the choice of annealing temperature or alloy composition, which depends on the ch...

Method of making permanent magnets

Cellular instabilities in directional solidification

2014 We have studied the morphology of the solid-liquid interface during the directional solidification of thin (5-150 03BCm) samples of a dilute binary mixture (CBr4/~ 0.1 % Br2) . Above a critical pulling speed, for a given temperature gradient and solute concentration, the interface, initially planar, breaks down into a periodic cellular pattern. The bifurcation from a planar to a cellular s...

Onset of sidebranching in directional solidification.

We use a computationally efficient phase-field formulation [B. Echebarria, Phys. Rev. E 70, 061604 (2004)] to investigate the origin and dynamics of sidebranching in directional solidification for realistic parameters of a dilute alloy previously studied experimentally [M. Gorgelin and A. Pocheau, Phys. Rev. E 57, 3189 (1998)]. Sidebranching is found to result either from noise amplification or...

Nonlinear Numerical Simulation of Permanent Magnets

Rare earth permanent magnet models are commonly used in the design of undulators and wigglers. Normally the operating point of the magnet in the B vs. H diagram corresponds to a linear reversible characteristic. The region of linearity is strongly dependent on the temperature. The operation of part of the magnet blocks in the region of non-linearity is responsible for the so-called irreversible...