Co-precipitation reduction diffusion process for preparing neodymium-boron permanent-magnet alloy

• Main Authors: YONGQIA ZHOU, PANWEN SHEN, XUYING HU
• Format: Patent
• Language: English
• Published: 25.02.1998
• Edition: 6
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CASTING; CHEMISTRY; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; INDUCTANCES; MAGNETS; MAKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; METALLURGY; PERFORMING OPERATIONS; POWDER METALLURGY; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES; TRANSFORMERS; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING METALLIC POWDER

The present invention relates to technological process of preparing neodymium-iron-boron permanent magnet alloy. In the process ammonium hydroxide and ammonium carbonate is used as precipitant and neodymium salt, ferrous salt and soluble boron compound, including leftover or waste material, are used as raw material. The process includes coprecipitation, hydrogen pre-reduction, calcium reduction and diffusion, rinse, drying to produce powder and other steps. Without using noble RE metals, the process has obvious reduced cost compared with available technology. The process leads nonmetal element boron directly into alloy, solves the problem of solid phase side reaction in hydrogen pre-reduction and avoids the loss and oxidation of neodymium in rinse so that it can produce alloy with purity higher than 99% with calcium content of 0.01-0.05 wt%.