R(Fe,M)_(12)(R=Y,Nd,Sm,Gd,Tb,Dy,Ho,Er;M=Ti,V)金属间化合物结构及磁性的研究

STRUCTURE AND MAGNETIC PROPERTIES OF R(Fe, M)n (R = Y,Nd,Sm,Gd,Tb,Dy,Ho,Er;M = Ti,V) INTERMETALLIC COMPOUNDS

本文用X射线、金相显微镜、扫描电镜、能谱、振动样品磁强计和磁称等方法,研究了R(Fe,M)_12(R为稀土元素,M为Ti,V)的晶体结构、微观组织和磁性。发现RFe_(10)Ti(除Nd外)的铸态合金不经长时间固溶就能形成ThMn_(12)型四方结构。确定出当Sm:Fe:Ti=1:10.5:1(原子比)时,Sm-Fe-Ti系铸态合金形成单相ThMn_(12)型四方结构。研究了Sm-Fe-Ti系合金粉末烧结体的微观组织及其成分。发现其微观组织中出现双晶界,双晶界的成分是富Fe的Fe-Ti化合物,经过适当的热处理工艺,可以消除这种双晶界。在Sm-Fe-Ti系合金的粉末烧结体中,存在着严重的稀土元素的偏聚,后续热处理工艺很难消除这种偏聚。

Crystal structure, microstructure and magnetic properties of R(Fe, M)12(R = Y, Nd, Sm, Gd, Tb, Dy, Ho, Er, M = Ti, V) compounds were studied by x-ray diffraction analysis, vibrating sample magnetometer ( VSM ), magnetic balance, optical microscopy and scanning electron microscopy ( SEM ). It was found that the cast alloys of RFenTi ( except Nd) before heat treatment were ThMn12-type structure and the single phase ThMn12-type stucture was obtained for Sm-Fe-Ti cast alloys when Sm: Ti, Fe=1: 1: 10.5 (atom ratio). A Kind of binary grainboundary of Fe-Ti (rich in Fe) compound was found in the powder-sintered Sm-Fe-Ti alloys. The segregation of Sm is serious in these alloys and it is hard to be eliminated by following heat-treatment.