GRAIN BOUNDARY ENGINEERING OF SINTERED MAGNETIC ALLOYS AND THE COMPOSITIONS DERIVED THEREFROM

• Main Author: ZAKOTNIK, Miha
• Format: Patent
• Language: English
• Published: 14.02.2019
• Subjects: BASIC ELECTRIC ELEMENTS; CASTING; ELECTRICITY; INDUCTANCES; MAGNETS; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; PERFORMING OPERATIONS; POWDER METALLURGY; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS; TRANSPORTING; WORKING METALLIC POWDER

The present disclosure is directed at methods of preparing rare earth-based permanent magnets having improved coercivity and remanence, the method comprising one or more steps comprising: (a) homogenizing a first population of particles of a first GBM alloy with a second population of particles of a second core alloy to form a composite alloy preform, the first GBM alloy being substantially represented by the formula: ACbRxCoyCudMz, the second core alloy being substantially represented by the formula G2Fe14B, where AC, R, M, G, b, x, y, and z are defined; (b) heating the composite alloy preform particles to form a population of mixed alloy particles; (c) compressing the mixed alloy particles, under a magnetic field of a suitable strength to align the magnetic particles with a common direction of magnetization and inert atmosphere, to form a green body; (d) sintering the green body; and (e) annealing the sintered body. Particular embodiments include magnets comprising neodymium-iron-boron core alloys, including Nd2Fe14B.