【作者】 呼努斯图；

【导师】 李国栋；

【作者基本信息】 内蒙古大学 ， 凝聚态物理， 2005， 硕士

【摘要】 双相纳米晶永磁材料以其优异的性能（如其理论磁性能可达1090kJ/m³,高于任何一种单相永磁材料）引起广泛关注。其中如何制备具有高性能且廉价的该种永磁材料是目前研究的热点之一。影响磁性能的主要因素有材料的成分、结构、组织（包括各相的晶粒形状、大小、数量及分布）等。而采用不同的制备方法及热处理工艺会得到不同的相结构及组织状态,也即得到不同的性能。本文采用快淬并退火晶化的方法制备双相纳米晶永磁材料,围绕改变退火工艺参数及添加不同种类的稀土元素Tb、Dy和过渡族元素Co、Ga等合金元素的方法,研究了各种影响因素与磁性能之间的关系。 采用溶体快淬工艺制备Nd_4.5Fe_77.5-xTb_xB₁₈（X=0;1）合金,分析退火温度、退火时间及添加元素Tb与磁性能的关系。发现对于Nd_4.5Fe_77.5B₁₈和Nd_4.5Fe_76.5Tb₁B₁₈合金来说,获得最佳磁性能的关键是晶化完整的前提下尽量减小晶粒的尺寸。退火时间不变、退火温度过低或过高;退火温度不变、退火时间过长或过短都不利于充分晶化和控制晶粒的大小;对低Nd高B的Nd_4.5Fe_77.5B₁₈合金,在高真空状态下,喷嘴口径为0.6mm、喷嘴与辊面距离为5mm、喷嘴压力为0.09MPa、辊轮速率为22m/s的条件下甩出来的非晶薄带在550℃下晶化热处理10min后磁性能达到最佳。添加1%的Tb元素,显著提高合金的矫顽力。但对合金的晶化温度及晶化时间影响不明显。 利用CDR-4P差热分析仪、X射线衍射、WK型振动样品磁强计（VSM）测试并分析了退火工艺参数对Nd₄Fe_78-xGa_xB₁₈（X=0;1）合金磁性能的影响,发现添加1%Ga元素对Nd₂Fe₁₄B/Fe₃B双相纳米永磁材料的晶化行为有很大的影响。两个样品的第一个放热峰温度差别不大,但是第二个放热峰温度随成分的变化很大。当在合金中添加元素Ga时增加了合金的黏度,所以在结晶过程中,原子在合金中的扩散比较困难,使得Nd₂Fe₁₄B和Fe₃B相的结晶在温度上滞后,从而提高了它们的析出温度。 分析了退火工艺对Nd₅Fe_77-xCo_xDy₁B₁₇（X=0;3）合金磁性能的影响,发现添加Co的合金随着退火时间的延长,磁性能保持下降趋势,但下降的速度很慢。两种情况（固定时间,改变退火温度;固定温度,改变退火时间）下合金Nd₅Fe₇₄Co₃Dy₁B₁₇的剩磁和矫顽力都高于合金Nd₅Fe₇₇B₁₈的剩磁和矫顽力。添加Dy所形成的Dy₂Fe₁₄B的各向异性场H_A比Nd₂Fe₁₄的各向异性场大,其次添加Dy后改善了合金的显微组织,细化了晶粒。更多还原

【Abstract】 Double-phase nanocomposite permanent magnet materials cause wide attention due to excellent magnetic properties. (For example (BH)_max can get 1090 kJ/m3 theoretically, which exceeds any simple-phase permanent magnet materials.). How to produce permanent magnets with high properties and cheapness is one of the hot points at present. The factors, such as component, structure of phase, organization which include grain shape, grain size, amount and distribution of every phase etc, influence magnetic properties, while permanent magnets that are produced by different methods and annealing process have different organizations, in other words they have different magnetic properties. Double-phase nanocomposite permanent magnetic materials were produced by the single roller rapid quenching and annealing in this dissertation, Relationship between all influent factors and magnetic properties was researched by changing annealing process and adding elements, including different kinds of rare-earth elements Tb and Dy and transitional elements Co and Ga etc.Nd4.5Fe77.5-xTbxB18 (x=0; 1) alloys were prepared by the single roller rapid quenching method and then analyzing relationship between annealing temperature, annealing time, addition element Tb and magnetic properties. To Nd4.5Fe77.5B18 and Nd4.5Fe76.5Tb1B18 alloys, it is critical to decrease crystalline size as possible under the precondition of crystallization integrated in order to get optimal magnetic properties annealing time unchangeable. The annealing temperature is passed through lowly either is overtopped. The annealing temperature is unchangeable, annealing time passes through to develop either passes through brief not benefiting sufficient crystalline substanceization and control crystalline grain size. To the compound metal that lets drop the tall B of Nd, Be living below the tall vacuum condition, spray head caliber is 0.6mm, the spray head against the roll is 5mm, spray head pressure is 0.09MPa, the rate of the roll is 22m/s, rolled Non-slight girdle of crystalline substance’s magnetic properties are optimal underthe condition of 550°C and annealing time lOmin. By doping 1 percent Tb, coercive of compound metal is improved obviously, but crystalline substance temperature and crystalline substance time effect to the compound metal unobvious.The effect of annealing process parameter on magnetic properties of Nd4.5Fe77.5-xGaxBi8 (x=0; 1) alloys was tested by a differential thermal analysis instrument, X-ray Diffractometer and a vibrating sample magnetometer (VSM). The results show that doping 1% Ga influenced crystalline substance action of double-phase nanocomposite permanent magnetic materials. There isn’t almost disparity between the first exothermic top temperature of two kind of samples, but the second exothermic top temperature changes bigly as component of samples changes. When Ga is doped in the alloys, viscosity is increased, so atom’s divergency is difficult in the alloys in the crystallization process, which crystallizing temperature of Nd2Fej4B phase and Fe3B phase is lagged, hence separation temperature is increased.Analying the effect of annealing process on the magnetic properties of Nd4.5Fe76.5-xCoxDyiBi8 (x=0, 3), we found that the magnetic effect of alloy doped Co maintain degradution tendency, however, the velocity of degradution is slow. The remanence and coercivity of Nd5Fe74Co3DyiBi7 is more than Nd5Fe77Big’s under two kinds of conditions (fixing annealing time, changing annealing temperature; fixing annealing temperature, changing annealing time). Nonisotropic field of Dy2Fei4B because of doping Dy is more than Nd2Fei4B’s, secondly microstructure of alloys is developed and crystalline grain is diminished after doping Dy.更多还原