METHOD FOR FORMING SOLID ALLOY HAVING UNIFORM FINE PARTICLE MICROSTRUCTURE BY RAPID TEMPERING OF MOLTEN ALLOY

摘要

PURPOSE: To form a solid ferromagnetic alloy in a form of uniform fine grains in a high yield by allowing a molten alloy precursor to collide against a rapidly- moving-type cooling surface and to scatter under a nonreactive atmosphere of a subatmospheric pressure and graduating the resultant alloy grains according to magnetic properties. CONSTITUTION: A molten alloy precursor is formed in a tank. Besides, a nonreactive atmosphere of He, Ar, N2 etc., at a subatmospheric pressure of =about 600 mmHg absolute pressure is made in the state that it is adjacent to the tank and also surrounds a rapidly-moving-type cooling surface. The molten alloy is made to flow from the tank to the cooling surface through the above atmosphere and discharged. By this procedure, a jet of the molten alloy is collided against the cooling surface under the above atmosphere to be quenched rapidly and passed as a discontinuous stream of solid alloy grains through the above atmosphere and scattered. By this method, the solid alloy in the form of fine grains having practically a narrow crystal size distribution, is produced. Then, the resultant alloy grains are graduated according to their magnetic properties to obtain a granular solid ferromagnetic alloy.