Enhancement of coercivity in Al and Cu added Nd-Fe-B sintered magnets by high feld annealing
Enhancement of coercivity in Al and Cu added Nd-Fe-B sintered magnets by high feld annealing
复制标题
高场退火提高 Al 和 Cu 添加 Nd-Fe-B 烧结磁体的矫顽力
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
K. Koyama
中科院分区：
文献类型：
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作者：
T. Akiya;H. Kato;M. Sagawa;K. Koyama
为了提高烧结 Nd-Fe-B 磁体的矫顽力 (Hc)，我们研究了退火过程中施加高达 140 kOe 的高磁场的影响。我们系统地研究了 Hc 的退火温度 (Ta) 依赖性。仅当样品含有少量Al和Cu添加剂且退火温度在Ta=500℃或550℃附近时，才观察到磁性退火引起的矫顽力增强现象。 DSC 测量表明这些温度可以分别解释为 Nd70Cu30 和 Al17Cu83 相的共晶点。在高达 250°C 的温度下测量了矫顽力增强样品中 Hc 和最大磁能积 (BH)max 的温度依赖性。我们发现，20°C 时 Hc = 14.6 kOe 的样品在 125°C 时的 (BH)max 值是 20°C 时 Hc = 9.8 kOe 的样品的两倍。
For the purpose of enhancement of coercivity (Hc) in sintered Nd-Fe-B magnets, we study the effects of high magnetic felds of up to 140 kOe applied during the annealing. We investigated the annealing temperature (Ta) dependence of Hc systematically. Coercivity enhancement phenomena induced by the magnetic annealing were observed only when the sample contains a small amount of Al and Cu additives, and the annealing temperature is in the vicinity of Ta = 500°C or 550°C. DSC measurements suggest that these temperatures can be interpreted as the eutectic points of Nd70Cu30 and Al17Cu83 phase, respectively. Temperature dependence of Hc and maximum energy product (BH)max in the coercivity-enhanced samples were measured up to 250°C. We have found that a sample with Hc = 14.6 kOe at 20°C gives a twice larger (BH)max value at 125°C as compared with those in the sample with Hc = 9.8 kOe at 20°C.