烧结钕铁硼磁体生产中碳杂质来源分析

Analysis on the source of C impurity in sintered Nd-Fe-B magnets

用常规生产工艺制备烧结钕铁硼磁体,应用碳硫含量分析仪进行碳元素检测,分析了生产过程中包括原材料、熔炼、氢爆碎、气流磨制粉(抗氧化剂)、成型机烧结等各工序环节引入的碳杂质。结果表明,相对于原材料中仅80～100 ppm的碳杂质,熔炼过程会引入约100 ppm的碳;气流磨过程引入碳含量约150 ppm;抗氧化剂引入约280 ppm碳;等静压引入的碳约40 ppm。这打破了人们对于烧结钕铁硼中碳杂质主要来自于抗氧化剂的认识。研究结果为减小磁体C含量,从而制备高性能磁体提供指导。

Sintered Nd-Fe-B magnet was produced by conventional processes.The content of C impurities introduced in various production stages in sintered NdFeB is studied with carbon/sulfur analyzer.It turns out that the stage of strip casting would introduce about 100 ppm carbon impurities against the content of 80-100 ppm in raw materials,jet milling adds about another 150 ppm C,antioxidant contributes about 280 ppm;CIP increases C by about 40 ppm.This discovery is contrary to the common knowledge that most of carbon impurities in sintered Nd-Fe-B magnets are derived from antioxidants.The study is of guidance for decreasing C impurity to produce high performance Nd-Fe-B magnets.