专利名称：Magnetic materials发明人：Yakov Bogatin申请号：US07/722730申请日：19910627公开号：US05180445A公开日：19930119
摘要：This invention relates to a process for producing a rare earth- containingpowder comprising crushing a rare earth-containing alloy in water, drying the crushedalloy material at a temperature below the phase transformation temperature of thematerial, and treating the crushed alloy material with a passivating gas at a temperaturefrom the ambient temperature to a temperature below the phase transformationtemperature of the material. Rare earth-containing alloys suitable for use in producingmagnets utilizing the powder metallurgy technique, such as Nd- Fe-B and Sm-Co alloys,can be used. The passivating gas can be nitrogen, carbon dioxide or a combination ofnitrogen and carbon dioxide. If nitrogen is used as the passivating gas, the resultantpowder has a nitrogen surface concentration of from about 0.4 to about 26.8 atomicpercent. Moreover, if carbon dioxide is used as the passivating gas, the resultant powderhas a carbon surface concentration of from about 0.02 to about 15 atomic percent. Thepresent invention further relates to the production of a permanent magnet comprisingthe above steps for producing the rare earth-containing powder, and then compactingthe powder, sintering the compacted material at a temperature of from about 900.degree. C. to about 1200° C., and heat treating the sintered material at a temperature offrom about 200° C. to about 1050. degree. C.
申请人：SPS TECHNOLOGIES, INC.
代理人：James D. Dee,Aaron Nerenberg
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