摘要
添加Nb元素会使(Nd,Pr)FeB/α-Fe纳米晶复合永磁合金的平均晶粒尺寸显著减小。用AFM观察快淬(Nd,Pr)10.5Fe81.5-xNbxCo2B6(x(at%,下同)=0.0,0.5,1.0,1.5,2.0,2.5,3.0)合金条带自由表面的显微结构,晶粒平均直径从不含Nb的(Nd,Pr)10.5Fe81.5Co2B6合金的175nm减小到含2at%Nb的(Nd,Pr)10.5Fe79.5Nb2Co2B6合金的68nm,晶粒平均直径细化了61%;当Nb超过2at%后,Nb含量的增加对晶粒的细化作用明显减弱,含3at%Nb的合金平均晶粒直径为63nm,比含2at%Nb仅细化了7.3%。含2at%Nb的(Nd,Pr)10.5Fe79.5Nb2Co2B6合金,粘结磁体磁性能达到最佳值,Br=0.665T,Hci=748kA·m-1,(BH)m=73kJ·m-3。Nb元素含量在2at%Nb以下时,合金晶粒粗大,磁性能较低;超过2at%后,富集在晶界处的富Nb晶间相加厚,晶粒间的交换作用和剩磁增强效应减弱,合金的内禀矫顽力虽然增加,但剩磁Br和最大磁能积(BH)m降低。
The average grain size of nanocrystalline （Nd, Pr）FeB/α-Fe alloys is significantly reduced by niobium addition. The microstructures of free surface for crystallized melt-spun ribbons are observed by means of atom force microscopy （AFM）. It is found that the average grain size is reduced by 61% from 175 nm of Nb-free （Nd, Pr）lo 5Fea1.5Co2B6 alloy to 68 nm of （Nd, Pr）10.5Fe79.5Nb2Co2B6, then by only 7.3% to 63 nm of （Nd, Pr）10.5Fe79.5Nb3Co2B6 if the Nb concentration over 2 at%, showing a weak effect on grains thining. The bonded magnet （with 3.25 wt% epoxy） of （Nd, Pr）10.5Fe79.5Nb2Co2B6 has the best combination of properties, i.e. Br=0.665 T, Hci=748 kA·m^-1, （BH）max=73 kJ·m^-3. The grains are coarse with low magnetic properties when the Nb concentration is below 2 at%. Above 2 at%, the intergranular phase rich in Nb turns thicker, so that the interaction of intergranular phases and the remanence enhancement are weakened, and the remanence Br and the maximum （BH）m, are decreased, even the intrinsic coercive force increasing for the alloy.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2007年第11期1987-1990,共4页
Rare Metal Materials and Engineering
基金
四川省自然科学基金重点资助项目(2004A110)
