Properties of /spl alpha/-Fe/Nd/sub 2/Fe/sub 14/B-type Nd-Fe-Co-V-B system bulk exchange-spring magnets prepared by spark plasma sintering
Properties of /spl alpha/-Fe/Nd/sub 2/Fe/sub 14/B-type Nd-Fe-Co-V-B system bulk exchange-spring magnets prepared by spark plasma sintering
复制标题
放电等离子烧结/spl α/-Fe/Nd/sub 2/Fe/sub 14/B型Nd-Fe-Co-V-B系块状交换弹簧磁体的性能
DOI：
10.1109/tmag.2003.812713
复制
发表时间：
2003
影响因子：
2.1
通讯作者：
M. Tani
中科院分区：
文献类型：
--
作者：
H. Ono;T. Tayu;N. Waki;T. Sugiyama;M. Shimada;M. Kanou;A. Fujiki;H. Yamamoto;M. Tani
我们对具有硬质 Nd/sub 2/Fe/sub 14/B 相和软质 /spl α/-Fe 相的 Nd/sub x/Fe/sub 85-x/Co/sub 8/V/sub 1/B/sub 6/ (x = 7-11) 块体交换弹簧磁体的微观结构、结晶过程、硬/软相体积比和磁性能进行了详细研究。大块交换弹簧磁体是通过将放电等离子烧结（SPS）方法应用于快速淬火含有非晶部件的带材而制成的。 SPS 方法是一种固体压缩烧结，可以在较低的温度和较短的保持时间下进行。获得的块体压块表现出优异的各向同性磁性能(BH)/sub max/大于130kJ/m/sup 3/，与快速淬火带的性能相同。在 SPS 致密化过程中，接近 Fe/sub 3/B 的化合物结晶后，硬质 Nd/sub 2/Fe/sub 14/B 相和软质 /spl α/-Fe 相几乎同时结晶。为了量化硬/软相比，必须考虑硬相的磁化状态。针对硬质相的饱和状态计算的相比与预测值非常吻合。块体磁体致密化，在起始带状粉末的颗粒之间没有任何晶粒生长，并且在带状粉末之间形成厚度约150-200nm的晶界区域。晶界区域没有成分偏析，其机械强度与粉粒内部相当。起始粉末内部出现小于50 nm的细晶粒，并且晶粒尺寸随着烧结过程中压缩压力的增加而减小。
We have made a detailed examination of the microstructure, crystallization process, volume ratio of hard/soft phases, and magnetic properties of Nd/sub x/Fe/sub 85-x/Co/sub 8/V/sub 1/B/sub 6/ (x = 7-11) bulk exchange-spring magnets having a hard Nd/sub 2/Fe/sub 14/B phase and a soft /spl alpha/-Fe phase. The bulk exchange-spring magnets were made by applying the spark plasma sintering (SPS) method to rapidly quenched ribbons containing amorphous parts. The SPS method is a type of solid compression sintering and can be performed at lower temperatures with a shorter hold time. The obtained bulk compacts showed excellent isotropic magnetic properties of (BH)/sub max/ greater than 130 kJ/m/sup 3/, equal to those of the rapidly quenched ribbons. In the densification process by SPS, crystallization of compounds close to Fe/sub 3/B was followed by nearly simultaneous crystallization of the hard Nd/sub 2/Fe/sub 14/B phase and the soft /spl alpha/-Fe phase. The magnetization state of the hard phase must be considered in order to quantify the hard/soft phase ratio. The phase ratio calculated for a saturation state of the hard phase agreed well with the predicted value. The bulk magnets densified without any crystal grain growth between the grains of the starting ribbon powders, and a grain boundary region of about 150-200 nm in thickness formed between the ribbon powders. There was no composition segregation in the grain boundary region, and its mechanical strength was equal to that of the interior of the powder grains. Fine crystal grains smaller than 50 nm occurred in the interior of the starting powders, and the grain size decreased with increasing compressive pressure during the sintering process.