2. Metallic materials of the alnico type

2.1 Alni. Alnico

Initially, the alni alloy of the AlNiFe ₂ type, discovered in Japan in 1932 by Mishima, had the following composition by weight: 58Fe-30Ni-12Al. Its coercive field of around 3.45 × 10 ⁴ A · m ^{– 1} (430 Oe) was twice as high as that of the best tungsten steels then in use. In 1938, additions of cobalt, carried out to increase M _s and T _C , as well as additions of copper and titanium, led to the discovery of the beneficial effect of heat treatment under a magnetic field on the anisotropic magnetic properties of this family of materials. Known...