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烧结Nd-Fe-B永磁材料显微结构优化与性能研究
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摘要
烧结Nd-Fe-B磁体是具有高磁性能和高性价比的新一代稀土永磁材料,广泛应用于各种高新技术领域。然而,矫顽力低、温度稳定性差和易腐蚀的缺点严重限制了其进一步发展和在各种重要领域的应用。烧结Nd-Fe-B材料的性能除与磁体成分直接相关外,显微结构也是一个重要的影响因素。因此,如何通过调整磁体显微结构来提高其综合性能是一个兼具重要理论和实际意义的科学问题。
     从调整和改善烧结Nd-Fe-B材料的显微结构出发,本文系统研究了晶界改性对材料磁性能、耐腐蚀性能和温度稳定性的影响,建立了纳米添加物在磁粉表面的理想分布模型,结合热力学计算,揭示了不同纳米添加物对主相Nd_2Fe_(14)B晶粒尺寸、分布形态及主相-富Nd相的界面结构的影响机制及其对磁体性能的作用机理;同时,通过气流磨过程中回收超细磁粉的晶界添加,明确了磁体性能和显微结构随添加量的变化规律,为降低磁体成本提供理论依据;此外,在研究磁体温度系数随其内禀性能和结构因素变化规律的基础上,掌握了高温度稳定性烧结Nd-Fe-B磁体的设计原则,并成功制备出低温度系数磁体。
     本文的主要研究结果如下:
     纳米添加物的晶界改性能够同时提高烧结Nd-Fe-B磁体的磁性能和耐腐蚀性能。研究发现,各种纳米粉的添加都能够提高磁体的矫顽力H_(cj),其中纳米Cu、SiO_2、ZnO和AlN的晶界添加能够有效细化主相晶粒,并使其分布更加均匀,有效增大了反磁化畴的形核场;纳米Cu、Zn、SiO_2和ZnO的晶界添加还能改善晶界富Nd相的性质,使其在主相周围分布更加均匀,减弱了晶粒间的磁交换耦合作用;而Dy_2O_3纳米粉的晶界添加,能够使主相晶粒表面磁硬化。纳米Cu、Zn、SiO_2和ZnO的晶界添加促进磁体的烧结致密化,能够有效提高密度,从而提高磁体的剩磁B_r和磁能积(BH)_(max);而纳米Dy_2O_3和AlN的作用则恰恰相反。此外,纳米Cu、Zn、SiO_2、ZnO和AlN的晶界添加能够提高晶界相的电极电位和优化显微结构,从而抑制磁体的晶间腐蚀,提高了磁体的耐腐蚀性能。
     根据热力学分析,阐述了各种纳米粉的添加对晶界富Nd相组成和性质的影响机制。研究发现,添加的金属Cu纳米粉和Zn纳米粉,在烧结过程中主要与晶界富Nd相发生化学反应,形成新的晶界相或溶入富Nd相中,而并没有进入主相。热力学计算表明,在晶界中添加的SiO_2和ZnO氧化物纳米粉与Nd在烧结温度下反应生成稳定的Nd_2O_3颗粒,以及元素Si或Zn;Nd_2O_3颗粒抑制了晶粒长大,Si和Zn改善了富Nd相的性质,进而优化了磁体显微结构。根据规则熔体Miedema理论模型计算,晶界添加的Dy_2O_3纳米粉与富Nd相反应还原生成的Dy易于扩散进入主相晶粒表面生成磁晶各向异性场更大的Dy_2Fe_(14)B,起到表面磁硬化的作用。
     采用气流磨过程中回收的超细磁粉的晶界添加制备了高性能低成本烧结Nd-Fe-B磁体,并揭示了超细磁粉添加量对磁体性能和显微结构的作用机制。研究表明,气流磨过程中回收超细磁粉的成分以稀土元素Nd、Pr和Dy为主,在晶界中添加能够提高磁体磁性能,尤其是矫顽力H_(cj)。超细磁粉的晶界添加能够减缓磁体液相烧结过程中溶质的扩散传质速度,抑制主相晶粒长大,细化了主相晶粒,提高了反磁化畴的形核场;同时有助于在主相晶粒表面形成高磁晶各向异性场的Dy_2Fe_(14)B和Pr_2Fe_(14)B,能够起到表面磁硬化的作用,从而显著提高磁体的矫顽力H_(cj);在添加量低于5 wt%时,也能提高磁体的磁能积(BH)_(max)。此外,超细粉的晶界添加还能有效降低磁体的矫顽力温度系数β和磁通不可逆损失h_(irr),提高了烧结Nd-Fe-B磁体的温度稳定性。
     建立了烧结Nd-Fe-B磁体温度系数与内禀性能和显微结构参量的定量关系,为设计低温度系数磁体提供了理论指导,并制备出高温度稳定性烧结Nd-Fe-B磁体。通过理论分析建立了矫顽力可逆温度系数β与磁晶各向异性场H_A和显微结构参量c/N_(eff)的定量关系,发现H_A越高、c/N_(eff)越大,β就越小。在此基础上,通过成分设计和磁体显微结构优化,成功制备了低温度系数的烧结Nd-Fe-B磁体,在20~150℃温度区间,β仅为-0.385%/℃;且在220℃时,磁体的矫顽力H_(cj)仍有557 kA/m,表明该磁体具有很高的温度稳定性。此外,根据磁体的最高工作温度与β的理论关系阐述了烧结Nd-Fe-B磁体矫顽力温度系数对其最高工作温度的影响规律。在相同的H_(cj)下,最高工作温度随β的降低而显著升高,表明降低β是制备高温度稳定性磁体行之有效的方法。
Sintered Nd-Fe-B magnet is a new generation of rare earth permanent magnetic material with outstanding magnetic properties and high cost performance,and has been applied widely in various hi-tech fields.However,the disadvantages of low coercivity,poor thermal stability,and easy corrosion seriously restrict its further development and application.In addition to the magnet composition,microstructure is also an important factor influencing the properties of sintered Nd-Fe-B magnets.Therefore,how to improve its overall properties through adjusting microstructure of the magnet is of both theoretical and practical significance.
     In this dissertation,aiming to adjust and modify the microstructure of sintered Nd-Fe-B materials,the effects of intergranular phase modification on the magnetic properties,corrosion resistance and thermal stability were systematically investigated.An ideal distribution model of nano-sized additives on the surface of magnetic powders was proposed.Several possible influencing mechanisms of different nano-sized additives on grain size and distribution of the main phase Nd_2Fe_(14)B,on the interface structure of main phase/Nd-rich phase,and on the properties of magnet were revealed on the basis of thermodynamic calculation.Meanwhile,the variation law of the properties and microstructure of magnet with additive content of ultrafine powders were made clear by intergranular addition.Furthermore,through investigating the variation of temperature coefficient with intrinsic property and microstructral parameter,the design principle of sintered Nd-Fe-B magnets with high thermal stability was suggested,and the magnet with low temperature coefficient was successfully prepared.
     The main results are as follows:
     Both the magnetic properties and corrosion resistance of sintered Nd-Fe-B magnets can be improved simultaneously by the intergranular phase modification of nano-sized additives.The results show that the additions of various nanopowders can all improve the coercivity H_(cj) of magnets.The intergranular additions of Cu,SiO_2,ZnO and AIN nanopowders can refine the grains of main phase effectively and make them distribute more homogeneously,increasing the nucleation field of reversed domain.The intergranular additions of Cu,Zn,SiO_2 and ZnO nanopowders can also improve the characteristics of Nd-rich phase,and make it distribute more homogeneously around the main phase,weakening the magnetic exchange coupling interaction.
     The intergranular additions of Dy_2O_3 nanopowders can harden the grain surface of the main phase.The intergranular additions of Cu,Zn,SiO_2 and ZnO nanopowders can promote the sintering densification of magnets,increasing the magnet density effectively,thereby improving the remanence B_r and magnetic energy product(BH)_(max);whereas the additives of Dy_2O_3 and AlN nanopowders played an opposite role.Furthermore,all the intergranular additions of Cu, Zn,SiO_2,ZnO and AlN nanopowders can increase the electrode potential of the intergranular phase and optimize the microstructure,consequently inhibiting intergranular corrosion and thus improving the corrosion resistance of magnet.
     On the basis of thermodynamic analysis,the influencing mechanism of various nanopowders addition on the composition and the physico-chemical characteristics of the intergranular Nd-rich phase have been described.It is found that the added Cu and Zn nanopowders reacted mainly with the intergranular Nd-rich phase to form new grain boundary phase or dissolved into the Nd-rich phase during sintering.Both of them do not enter the main phase.Thermodynamic calculations show that SiO_2 and ZnO nanopowders added into grain boundaries react with Nd-rich phase and form Nd_2O_3 particles,as well as the elements Si or Zn at the sintering temperature.These Nd_2O_3 particles can inhibit the grain growth of the main phase,while Si and Zn can improve the physico-chemical characteristics of the Nd-rich phase, consequently optimizing the microstructure.According to the Miedema theoretical models for the regular melt,Dy formed through reduction reaction between Dy_2O_3 and the Nd-rich phase can easily diffuse into the main phase grain surface to form Dy_2Fe_(14)B with higher magnetocrystalline anisotropy field,playing a role of surface magnetic hardening.
     The high performance,low cost sintered Nd-Fe-B magnet has been prepared through intergranular addition of ultrafine powders recycled during jet-milling process.The influencing mechanism of additive content of ultrafine powders on the properties and microstructure is also revealed.The results show that the composition of ultrafine powders consists mainly of rare earth elements of Nd,Pr and Dy.The intergranular addition can improve the magnetic properties, especially the coercivity H_(cj).The intergranular addition of ultrafine powders can decrease the diffusion mass transfer rate of solute during sintering,hindering the grain growth of the main phase,and thus improving the nucleation field of reversed domain.The intergranular addition of ultrafine powders is helpful to the formation of Dy_2Fe_(14)B and Pr_2Fe_(14)B with higher magnetocrystalline anisotropy field on the grain surface of the main phase,playing a role of surface magnetic hardening,consequently improving the coercivity H_(cj) of magnet significantly. When the additive content is below 5 wt%,the magnetic energy product(BH)_(max) can also be improved.Moreover,the intergranular addition of ultrafine powders also results in the decrease of the temperature coefficient of coercivityβand the irreversible flux loss h_(irr),which improves the thermal stability of sintered Nd-Fe-B magnets.
     The quantitative relationship between temperature coefficient and intrinsic property and microstructral parameter has been established,which provide a theoretical guidance for designing low temperature coefficient magnet.Sintered Nd-Fe-B magnet with high thermal stability has also been prepared.The relationship between temperature coefficient of coercivityβand magnetocrystalline anisotropy field H_A and microstructral parameter c/N_(eff) have been established through theoretical analysis,it is found that the higher H_A is and the bigger c/N_(eff) is, the smallerβis.Based on this,the sintered Nd-Fe-B magnet with low temperature coefficient have been successfully prepared through composition design and microstructure optimization,βis only -0.385%/℃at the temperature interval of 20~150℃.Its coercivity H_(cj) can reach 557 kA/m at 220℃,indicating that the magnet possesses very high thermal stability.Furthermore, according to the theoretical relationship between highest operating temperature andβ,the influence of temperature coefficient of coercivity for sintered Nd-Fe-B magnets on the highest operating temperature is described.At the same H_(cj),the highest operating temperature increases significantly with the decrease ofβ,suggesting that decreasingβis an effective method to prepare magnet with high thermal stability.
引文
[1]D.Jiles.Introduction to magnetism and magnetic materials.CRC press,1998.
    [2]J.M.D.Coey.Rare-earth magnets.Endeavour,1995,19(4):146-151.
    [3]K.Stnart,G.Hoffer,J.Olson,W.Ostertag,J.J.Becker.A Family of new cobalt-base permanent magnet materials.J.Appl.Phys.,1967,38(3):1001-1002.
    [4]K.H.J.Buschow,W.Liuten,P.A.Naastepad,O.F.F.Westendorp.Magnet material with a(BH)_(max) of 18.5million gaussorested.Philips Tech.Rev.,1968,29:336-337.
    [5]D.K.Das.Twenty million energy product samarium-cobalt magnet.IEEE Trans.Magn.,1969,5(3):214-216.
    [6]D.K.Das.Influence of sintering temperature on magnetic properties of samarium-cobalt magnets.IEEE Trans.Magn.,1971,7(3):432-435.
    [7]K.S.V.L.Narasimhan,W.E.Wallace.Magnetic anisotropy of substituted R_2Co_(17)compounds(R=Nd,Sm,Er and Yb).IEEE Trans.Magn.,1977,13(5):1333-1335.
    [8]T.Ojima,S.Tomizawa,T.Yoneyama,T.Hori.Magnetic properties of a new type of rare-earth cobalt magnets Sm_2(Co,Cu,Fe,M)_(17).IEEE Trans.Magn.,1977,13(5):1317-1319.
    [9]J.J.Croat,J.F.Herbst,R.W.Lee,F.E.Pinkerton.Pr-Fe and Nd-Fe based materials:A new class of high-performance permanent magnets.J.Appl.Phys.,1984,55(6):2078-2082.
    [10]N.C.Koon,B.N.Das.Crystallization of FeB alloys with rare earths to produce hard magnetic materials (invited).J.Appl.Phys.,1984,55(6):2063-2066.
    [11]G.C.Hadjipanayis,R.C.Hazelton,K.R.Lawless.Cobalt-free permanent magnet materials bascd on iron-rare-earth alloys(invited).J.Appl.Phys.,1984,55(6):2073-2077.
    [12]M.Sagawa,S.Fujimura,M.Togawa,H.Yamamoto,Y.Matsuura.New material for permanent magnets on a base of Nd and Fe.J.Appl.Phys.,1984,55(6):2083-2087.
    [13]S.Hirosawa,Y.Matsuura,H.Yamamoto,S.Fujimura,M.Sagawa,H.Yamauchi.Magnetization and magnetic anisotropy of R_2Fe_(14)B measured on single crystals.J.Appl.Phys.,1986,59(3):873-879.
    [14]D.Goll,H.Kronm(u|¨)ller.High-performance permanent magnets.Naturwissenschaften,2000,87(10):423-438.
    [15]全国稀土永磁协作网.中国稀土永磁产业的回顾与发展.磁性材料及器件,2001,32(2):18-22.
    [16]周寿增,董清飞.超强永磁体-稀土铁系永磁材料.北京:冶金工业出版社,2004.
    [17]Y.Matsuura.Recent development of NdFeB sintered magnets and their applications.J.Magn.Magn.Mater.,2006,303(2):344-347.
    [18]金瑞湘.高性能烧结Nd-Fe-B磁体生产的一些新技术.电工合金.1999.3:1-7.
    [19]罗阳.全球NdFeB磁体产业变化与发展的25年.磁性材料及器件,2008,39(6):9-18.
    [20]D.Brown,B.M.Ma,Z.M.Chen.Developments in the processing and properties of NdFeb-type permanent magnets.J.Magn.Magn,Mater.,2002,248(3):432-440.
    [21]J.Fidler,K.G.Knoch.Electron microscopy of Nd-Fe-B based magnets.J.Magn.Magn.Mater.,1989,80(1):48-56..
    [22]王建平.钕铁硼稀土永磁材料及其研究进展.材料工翟,1996,(3):47-49.
    [23]J.Fidler.On the role of the ND-rich phases in sintered ND-FE-B magnets.IEEE Trans.Magn.,1987,23(5):2106-2108.
    [24]J.Fidler.Analytical microscope studies of sintered Nd-Fe-B magnets.IEEE Trans.Magn.,1985,21(5):1955-1957.
    [25]J.F.Herbst,J.J.Croat,F.E.Pinkerton,W.B.Yelon.Relationships between crystal structure and magnetic properties in Nd_2Fe_(14)B.Phys.Rev.B,1984,29(7):4176-4178.
    [26]D.Givord,H.S.Li,J.M.Moreau.Magnetic properties and crystal structure of Nd_2Fe_(14)B.Solid State Commun.,1984,50(6):497-499.
    [27]K.Hiraga,M.Hirabayashi,M.Sagawa,Y.Matsuura.A study of microstructures of grain boundaries in sintered Fe_(77)Nd_(15)B_8 permanent magnet by high-resolution electron microscopy.Jpn.J.Appl.Phys.,1985,24(6):699-703.
    [28]W.Z.Tang,S.Z.Zhou,R.Wang,C.D.Graham.An investigation of the Nd-rich phases in the Nd-Fe-B system.J.Appl.Phys.,1988,64(10):5516-5518.
    [29]N.A.El-Masry,H.H.Stadelmaier.Nanometer particles in the intergranular microstructure of Fe-Nd-B permanent magnets.Mater.Lett,1985,3(9-10):405-408.
    [30]R.Ramesh,J.K.Chen,G.Thomas.On the grain-boundary phase in iron rare-earth boron magnets.J.Appl.Phys.,1987,61(8):2993-2998.
    [31]Y.Shinba,T.J.Konno,K.lshikawa,K.Hiraga.Transmission electron microscopy study on Nd-rich phase and grain boundary structure of Nd-Fe-B sintered magnets.J.Appl.Phys.,2005,97(5):053504-1-8.
    [32]A.Bezinge,H.F.Braun,J.Muller,K.Yvon.Tetragonal rare earth(R) iron borides,R_(1+ε)Fe_4B_4(ε≌0.1),with incommensurate rare earth and iron substructures.Solid State Commun.,1985.55(2):131-135.
    [33]D.Givord,J.M.Moreau,P.Tenaud.Nd_5Fe_(18)B_(18)(Nd_(1.11)Fe_4B_4),a new nowotny-like phase,structural and magnetic properties.Solid State Commun.,1985,55(4):303-306.
    [34]Z.B.Zhao,S.K.Xia,C.R.Wang,R.Z.Ma.Nd_(1+ε)Fe_4B_4,a novel system of infinitely adaptive structures.J.Phys.:Condens.Matter,1989,1(41):7513-7520.
    [35]H.R.Kirchmayr.Permanent magnets and hard magnetic materials.J.Phys.D:Appl.Phys.,1996,29(11):2763-2778.
    [36]W.Rodewald,M.Katter,B.Wall,R.Blank,G.W.Reppel,H.D.Zilg.Dependence of the coercivity H_(cj) of high energy Nd-Fe-B magnets on the alignment coefficient.IEEE,Trans.Magn.,2000,36(5):3279-3281.
    [37]R.W.Gao,D.H.Zhang,H.Li,J.C.Zhang.Effects of the degree of grain alignment on the hard magnetic properties of sintered NdFeB magnets.Appl.Phys.A,1998,67(3):353-356.
    [38]H.Kronmuller,K.D.Durst,M.Sagawa.Analysis of magnetic hardening mechanism in RE-Fe-B permanent magnets,J.Magn.Magn.Mater.,1988,74(3):291-302.
    [39]D.Li and K.J.Strnat.Domain behavior in sintered Nd-Fe-B magnets during field-induced and thermal magnetization change.J.Appl.Phys.,1985,57(8):4143-4145.
    [40]R.W.Gao,D.H.Zhang,H.Li,S.T.Jiang,S.Z.Zhou,F.B.Li,L.D.Zhang.Coercivity and its dependence on the strength of alignment magnetic field in Nd-Fe-B sintered magnets.J.Appl.Phys.,1995,78(2):1156-1159.
    [41]D.Givord,Q.Lu,M.F.Rossignol,P.Tenaud,T.Viadieu.Experimental approach to coercivity analysis in hard magnetic materials.J.Magn.Magn.Mater.,1990,83(1-3):183-188.
    [42]J.Fidler,T.Schrefl,S.Hoefinger,M.Hajduga.Recent developments in hard magnetic bulk materials.J.Phys.:Condens.Matter,2004,16(5):S455-S470.
    [43]Y.Kaneko,F.Kuniyoshi,N.Ishigaki.Proven technologies on high-performance Nd-Fe-B sintered magnets.J.Alloys Compd.,2006,408-412:1344-1349.
    [44]高汝伟,王标,刘汉强.韩广兵,白岗,孙艳,刘涛.高性能烧结钕铁硼磁体的研究与开发(一).磁性材料及嚣件,2004,35(6):1-5.
    [45]J.Bernardi,J.Fidler,M.Sagawa,Y.Hirose.Microstructural analysis of strip cast Nd-Fe-B alloys for high(BH)_(max) magnets.J.Appl.Phys.,1998,83(11):6396-6398.
    [46]P.J.McGuiness,E.Devlin,I.R.Harris,E.Rozendaal,J.Ormerod.A study of Nd-Fe-B magnets produced using a combination of hydrogen decrepitation and jet milling.J.Mater.Sci.,1989,24(7):2541-2548.
    [47]M.Verdier,J.Morros,D.Pere,I.R.Harris.Hydrogen absorption behaviours of some Nd-Fe-B-type alloys.IEEE Trans.Magn.,1994,30(2):660-662.
    [48]M.Sagawa,H.Nagata.Novel processing technology for permanent magnets.IEEE Trans.Magn.,1993,29(6):2747-2751.
    [49]H.Nagata,M.Sagawa.Toward an process for the NdFeB sintered magnets.Proc.17th Inter.Workshop on Rare Earth Magnets and Their Applications,Newark Delare,USA,2002.
    [50]Y.Kaneko.Highest performance of Nd-Fe-B magnet over 55 MGOe.IEEE Trans.Magn.,2000,36(5):3275-3278.
    [51]E.Otsuki,T.Otusuka,T.Imai.Processing and magnetic properties of sintered Nd-Fe-B magnets.Proc.11th Int.Workshop on Rare-Earth Magnets and Their Applications,Pittsburgh,1990,1:328-340.
    [52]M.Honshima,K.Ohashi.High-energy NdFeB magnets and their applications.J.Mater.Eng.Perform,1994,3(2):218-222.
    [53]W.Rodewald,B.Wall,M.Katter,K.Uestuener.Top Nd-Fe-B magnets with greater than 56 MGOe energy density and 9.8 kOe coercivity.IEEE Trans.Magn.,2002,38(5):2955-2957.
    [54]K.Hirota,H.Nakamura,T.Minowa,M.Honshima.Coercivity Enhancement by the Grain Boundary Diffusion Process to Nd-Fe-B Sintered Magnets.IEEE Trans.Magn.,2006,42(10):2909-2911.
    [55]M.Takahashi,K.Uchida,F.Taniguchi,T.Mikamoto.High performance Nd-Fe-B sintered magnets made by the wet process.J.Appl.Phys.,1998,83(11):6402-6404.
    [56]J.Fidler,T.Schrefl.Overview of Nd-Fe-B magnets and coercivity(invited).J.Appl.Phys.,1996,79(8):5029-5034.
    [57]O.M.Ragg,I.R.Harris.A study of the effects of the addition of various amounts of Cu to sintered Nd-Fe-B magnets.J.Alloys Compd,1997,256(1-2):252-257.
    [58]S.Pandian,V.Chandrasekaran,G.Markandeyulu,K.J.L.Iyer,K.V.S.Rama Rao.Effect of Co,Dy and Ga on the magnetic properties and the microstructure of powder metallurgically processed Nd-Fe-B magnets.J.Alloys Compd.,2004,364(1-2):295-303.
    [59]L.Q.Yu,Y.H.Wen,M.Yan.Effects of Dy and Nb on the magnetic properties and corrosion resistance of sintered NdFeB.J.Magn.Magn.Mater.,2004,283(2-3):353-356.
    [60]G.Bai,R.W.Gao,Y.Sun,G.B.Han,B.Wang.Study of high-coercivity sintered NdFeB magnets.J.Magn.Magn.Mater.,2007,308(1):20-23.
    [61]石永金,张小立,易毅刚.铽含量对耐热钕铁硼永磁材料的磁性能的影响.稀有金属材料与工程, 1999,28(4):236-239.
    [62]D.Li,E.D.Xu,J.L.Liu,Y.X.Du.The 2-17 type Sm_(2-x)HRE_xCo_(10)Cu_(1.5)Fe_(3.2)Zr_(0.2)(HRE=Gd,Tb,Dy,Ho,Er) magnets with low temperature coefficient.IEEE Trans.Magn.,1980,16(5):988-990.
    [63]B.M.Ma;K.S.V.L.Narasimhan,J.C.Hurt.NdFeB magnets with zero temperature coefficient of induction.IEEE Trans.Magn.,1986,22(5):1081-1083.
    [64]Z.H.Hu,F.Z.Lian,M.G.Zhu,W.Li.Effect of Tb on the intrinsic coercivity and impact toughness of sintered Nd-Dy-Fe-B magnets.J.Magn.Magn.Mater.,2008,320(11):1735-1738.
    [65]C.Lin,Z.X.Liu,X.F.Xu.Magnetic properties of Nd2(Fe_(1-x)Co_x)_(14)4B and Y_2(Fe_(1-x)CO_x)_(14)B.IEEE Trans.Magn.,1987,23(5):2296-2298.
    [66]Y.Matsuura,S.Hirosawa,H.Yamamoto,S.Fujimura,M.Sagawa.Magnetic properties of the Nd_2(Fe_(1-x)Co_x)_(14)B system.Appl.Phys.Lett,1985,46(3):308-310.
    [67]G.Asti,F.Bolzoni,L.Pareti.Magnetic anisotropy of RE-magnets.IEEE Trans.Magn.,1987,23(5):2521-2526.
    [68]M.Sagawa,S.Fujimura,H.Yamamoto,Y.Matsuura,K.Hiraga.Permanent magnet materials based on the rare earth-iron-boron tetragonal compounds(invited).IEEE Trans.Magn.,1984,20(5):1584-1589.
    [69]周寿增,郭灿杰,呼琴,李春和.高磁能积低温度系数的铁基永磁合金的磁性能与组织结构.北京钢铁学院学报,1988,10(3):317-322.
    [70]S.Hirosawa,Y.Yamaguchi,K.Tokuhara,H.Yamamoto,S.Fujimura,M.Sagawa.Magnetic properties of Nd_2(Fe_(1-x)M_x)14B measured on single crystals(M=Al,Cr,Mn and Co).IEEE Trans.Magn.,1987,23(5):2120-2122.
    [71]B.M.Ma,W.L.Liu,Y.L.Liang,D.W.Scott,C.O.Bounds.Comparison of the improvement of thermal stability of NdFeB sintered magnets:intrinsic and/or microstructurai.J.Appl.Phys.,1994,75(10):6628-6630.
    [72]T.Mizoguchi,I.Sakai,H.Niu,K.Inomata.Magnetic properties of Nd-Fe-B magnets with both Co and AI addition.IEEE Trans.Magn.,1987,23(5):2281-2283.
    [73]H.Yamamoto,S.Hirosawa,S.Fujimura,K.Tokuhara,H.Nagata,M.Sagawa.Metallographic study on Nd-Fe-B sintered magnets.IEEE Trans.Magn.,1987,23(5):2100-2103.
    [74]S.Dai,A.H.Morrish,X.Z.Zhou,B.P.Hu,S.G.Zhang.M(o|¨)ssbauer study of the permanent-magnet material Nd_2(Fe_(1-x)Ni_x)_(14)B.J.Appl.Phys.,1988,63(8):3722-3724.
    [75]O.Moze,L.Pareti,M.Solzi,F.Bolzoni,W.I.F.David,W.T.A.Harrison,A.W.Hewat.Magnetic structure and preferential site occupation in manganese- and chromium-substituted Y_2Fe_(14)B compounds,J.Less Common Met.1988,136(2):375-383.
    [76]C.D Fuerst,G.P Meisner,F.E Pinkerton,W.B Yelon.Site occupancy in erbium-iron-manganese-boron alloys.J.Less Common Met.1987,133(2):255-261.
    [77]W.Rodewald,W.Fernengel.Properties of sintered Nd-Fe-TM-B magnets.IEEE Trans.Magn.,1988,24(2):1638-1643.
    [78]E.Rozendaal.Coercivity dependence of sintered NdFeB magnets on Al content and the alloying route.IEEE Trans.Magn.,1990,26(5):2631-2633.
    [79]K.G.Knoch,G.Schneider,J.Fidler,E.T.Henig,H.Kronm(u|¨)ller.Al-doped Nd-Fe-B permanent magnets:wetting and microstructural investigations.IEEE Trans.Magn.,1989,25(5):3426-3428.
    [80]S.Szymura,H.Bala,Y.M.Rabinovich,J.Wiechula.Properties of sintered Al substituted NdFeB magnets.Mod.Phys.Lett.B,1998,12(6&7):257-263.
    [81]S.Pandian,V.Chandrasekaran,G.Markandeyulu,K.J.L.Iyer,K.V.S.Rama Rao.Effect of Al,Cu,Ga,and Nb additions on the magnetic properties and microstructural features of sintered NdFeB.J.Appl.Phys.,2002,92(10):6082-6086.
    [82]S.Pandian,V.Chandrasekaran,K.J.L Iyer,K.V.S.Rama Rao.Investigations on the metallurgical features and magnetic properties of Nd_(16.8)Fe_(75.7-x)Al_xB_(7.5),0≤x≤6.IEEE Trans.Magn.,2001,37(4):2489-2492.
    [83]Y.C.Yang,D.E.Tharp,G.J.Long,O.A.Pringle,W.J.James.A M(o|¨)ssbauer effect study of the structural and magnetic properties of Y_2(Fe_(1-x)Al_x)_(14)B.J.Appl.Phys.,1987,61(8):4343-4345.
    [84]J.Strzeszewski,G.C.Hadjipanayis,A.S.Kim.The effect of Al substitution on the coercivity of Nd-Fe-B magnets.J.Appl.Phys.,1988,64(10):5568-5570.
    [85]J.F.Hu,Z.X.Wang,Y.Z.Wang,J.G.Zhao,X.L.Rao,N.N.Zhang.Study of the coercivity for Nd-Fe-B-Ga sintered magnets.IEEE Trans.Magn.,1989,25(5):3429-3430.
    [86]K.G.Knoch,B.Grieb,E.T.Henig,H.Kronm(u|¨)ller,G.Petzow.Upgraded Nd-Fe-B-AD(AD=Al,Ga)magnets:wettability and microstructure.IEEE Trans.Magn.,1990,26(5):1951-1953.
    [87]X.C.Kou,F.R.de Boer,H.Kronm(u|¨)ller.Coercivity of sintered Nd(Fe_(0.92-x)Ga_xB_(0.08))_(5.5) permanent magnets.J.Appl.Phys.,1998,83(11):6408-6410.
    [88]M.Endoh,M.Tokunaga,H.Harada.Magnetic properties and thermal stabilities of Ga substituted Nd-Fe-Co-B magnets.IEEE Trans.Magn.,1987,23(5):2290-2292.
    [89]M.Tokunaga,H.Kogure,M.Endoh,H.Harada.Improvement of thermal stability of Nd-Dy-Fe-Co-B sintered magnets by additions or Al,Nb and Ga.IEEE Trans.Magn.,1987,23(5):2287-2289.
    [90]J.F.Hu,Y.Z.Wang,X.W.Li,L.Yin,M.Y.Feng,D.Y.Dai,T.Wang,J.G.Zhao,Z.X.Wang.The effects of addition of Nb,Mo and Ga on the magnetic properties of Nd-Fe-B alloys.J.Phys.Colloques,1988,49(12):601-602.
    [91]C.R.Quan,J.G.Zhao,Y.Z.Wang,L.Yin,B.G.Shen,Z.X.Cheng,Y.E Cheng,S.W.Niu.Neutron diffraction and M(o|¨)ssbauer studies of Ga site preference in Nd_2Fe_(14)B and Fe internal-field assignments.Phys.Rev.B,1990,42(10):6697-6699.
    [92]A.T.Pedziwiatr,S.G.Sankar,W.E.Wallace.The effect of Ga substitution on the magnetic properties of Nd_2Fe_(14)B,Pr_2Fe_(14)B,and PrCo_5.J.Appl.Phys.,1988,63(8):3710-3712.
    [93]S.K.Chen,J.G.Duh,H.C.Ku.Structural and magnetic properties of pseudoternary Nd_2(Fe_(1-x)Cu_x)14B compounds.J.Appl.Phys.,1988,63(8):2739-2741.
    [94]C.H.Lin,C.J.Chen,C.D.Wu,W.C.Chang,S.K.Chen,T.S.Chin.Magnetic properties of sintered permanent magnets R-Fe-Cu-B(R=Pr,Nd).IEEE Trans.Magn.,1990,26(5):2607-2609.
    [95]A.Kianvash,I.R.Harris.Magnetic properties of the sintered magnets produced from a Nd-Fe-B-Cu-type materials.J.Appl.Phys.,1991,70(10):6453-6455.
    [96]K.G.Knoch,A.Kianvash,I.R.Harris.Nd-Fe-B-Cu HD-processed sintered magnets:properties and microstructure.IEEE Trans.Magn.,1992,28(5):2142-2144.
    [97]O.M.Ragg,I.R.Harris.A study of the effects of Cu-addition on the annealing behaviour and microstructures of Nd-Fe-B type sintered magnets.IEEE Trans.Magn.,1993,29(6):2758-2760.
    [98]K.Ohmori,L.Li,C.D.Graham.Effect of added Cu on the Nd-rich phase in hot-deformed NdFeB magnets.IEEE Trans.Magn.,1992,28(5):2139-2141.
    [99]A.Kianvash,I.R.Harris.The effect of heat treatment on the microstructure and magnetic properties of sintered magnets produced from Nd-Fe-B based alloys with and without Cu substitution.J.Alloys Compd.,1992,178(1-2):325-341.
    [100]马宝钿,宋晓平,张湃,王笑天.Zn对NdFeB基稀土永磁体磁性能和显微组织的影响.稀的金属材料与工程,1992,21(3):33-36.
    [101]C.H.Lin,S.K.Chen,K.D.Lin,W.C.Chang,T.S.Chin.Magnetic properties and microstructure of magnesium-doped Nd-Fe-B magnets.J.Appl.Phys.,1988,64(10):5513-5515.
    [102]M.M.Raja,A.Narayanasamy,V.Ravichandran.~(57)Fe M(o|¨)ssbauer effect and X-ray studies of Nd-Fe-Sn-B permanent magnetic materials.J.Magn.Magn.Mater.,1996,159(3):345-351.
    [103]P.Schrey,M.Velicescu.Influence of Sn additions on the magnetic and microstructural properties of Nd-Dy-Fe-B magnets.J.Magn.Magn.Mater.,1991,101(1-3):417-418.
    [104]M.Rosenberg,R.J.Zhou,M.Velicescu,P.Schrey,G.Filoti.Metamagnetism and spin arrangement in Nd_6Fe_(13)Sn.J.Appl.Phys,,1994,75(10):6586-6588.
    [105]张正富,黄伯云,付应生,陈彪,敬安晋,张明.Sn对烧结钕铁硼合金磁性能的影响.中南工业大学学报,2000,31(2):156-159.
    [106]张正富,黄伯云,周科朝,左铁镛.Sn对烧结钕铁硼合金高温磁性能的影响及机制分析.材料科学与工艺,2000,8(2):65-69.
    [107]S.F.H.Parker,P.J.Grundy,J.Fidler.Electron microscope study of precipitation in a niobium-containing (Nd,Dy)-Fe-B sintered magnet.J.Magn.Magn,Mater.,1987,66(1):74-78.
    [108]T.Ishikawa,Y.Hamada,K.Ohmori.Domain wall pinning by fine precipitates.IEEE Trans.Magn.,1989,25(5):3434-3436.
    [109]W.H.Cheng,W.Li,C.J.Li,X.M.Li.The role of Nb addition in Nd-Fe-B sintered magnets with high performance.J.Alloys Compd.,2001,319(1-2):280-282.
    [110]M.Tokunaga,H.Harada,S.R.Trout.Effect of Nb additions on the irreversible losses of Nd-Fe-B type magnets.IEEE Trans.Magn.,1987,23(5):2284-2286.
    [111]P.J.Pollard,P.J.Grundy,S.F.H.Parker,D.G.Lord.Effect of Zr additions on the microstructural and magnetic properties of NdFeB based magnets.IEEE Trans.Magn,,1988,24(2):1626-1628.
    [112]A.Fujita,I.R.Harris.Magnetic anisotropy in arc-cast Nd-Fe-B-Zr alloys.IEEE Trans.Magn.,1993,29(6):2803-2805.
    [113]A.Shaaban.Effects of Zr substitution in NdFeB permanent magnets.AIP Conf.Proc.,2007,909(1):63-67.
    [114]Y.Kitano,J.Shimomura,M.Shimotomai.Analytical electron microscopy of Ti-doped Nd-TM-B magnets,J.Appl.Phys.,1991,69(8):6055-6057.
    [115]T.S.Chin,C.H.Lin,Y.H.Huang,J.M.Yau.Enhanced thermal stability of sintered(Nd,Dy)(Fe,Co)B magnets by the addition of Ta or Ti.IEEE Trans.Magn.,1993,29(6):2788-2790.
    [116]M.Leonowicz.Magnetic properties and microstructure of Nd_(16)Fe_(76-x)M_xB_8 magnets(M=Ga,Cr,Nb,Bi,Sn,Zr,W,V,Mo,Mn).J.Magn.Magn.Mater.,1990,83(1-3):211-213.
    [117]X.F.Shen,Y.Q.Wang,Z.T.Diao,X.F.Liu.The effect of molybdenum on the magnetic properties of the Nd-Fe-Co-B system.J.Appl.Phys.,1987,61(8):3433-3435.
    [118]S.Hirosawa,S.Mino,H.Tomizawa.Improved corrosion resistance and magnetic properties of Nd-Fe-B-type sintered magnets with Mo and Co.J.Appl.Phys.,1991,69(8):5844-5846.
    [119]W.Rodewald,P.Schrey.Structural and magnetic properties of sintered Nd_(14.4)Fe_(67.0-x)Co_(11.8)Mo_xB_(6.8)Magnets.IEEE Trans.Magn.,1989,25(5):3770-3772.
    [120]E.Adler,W.Rodewald,B.Wall.Temperature stability and corrosion behavior of sintered Nd-Dy-Fe-Co-TM-B,TM:V,Mo.J.Appl.Phys.,1991,70(10):6637-6639.
    [121]S.Hirosawa,H.Tomizawa,S.Mino,A.Hamamura.High-coercivity Nd-Fe-B-type permanent magnets with less dysprosium.IEEE Trans.Magn.,1990,26(5):1960-1962.
    [122]P.Tenaud,F.Vial,M.Sagawa.Improved corrosion and temperature behaviour of modified Nd-Fe-B magnets.IEEE Trans.Magn.,1990,26(5):1930-1932.
    [123]M.Sagawa,P.Tenaud,F.Vial,K.Hiraga.High coercivity Nd-Fe-B sintered magnet containing vanadium with new microstructure.IEEE Trans.Magn.,1990,26(5):1957-1959.
    [124]M.Verdier,J.Morros,D.Pere,N.Shell,I.R.Harris.Stability of Nd-Fe-B powders obtained by hydrogen decrepitation.IEEE Trans.Magn.,1994,30(2):657-659.
    [125]W.L.Liu,Y.L.Liang,B.M.Ma,C.O.Mounds.Effects of alloy composition and/or casting method on the amount Fe-precipitation in NdFeB alloys.Magnetics Conference,1992.Digests of Intermag '92.,International,1992:25-25.
    [126]J.Bernardi,J.Fidler,F.F(o|¨)dermayr.The effect of V or W additives to microstructure and coercivity of Nd-Fe-B based magnets.IEEE Trans.Magn.,1992,28(5):2127-2129.
    [127]C.H.Lin,T.S.Chin,Y.H.Huang,J.M.You,K.H.Cheng,T.Y.Chu.Magnetic hardening of Cr-/W-added NdDyFeCoB sintered magnets.IEEE Trans.Magn,,1993,29(6):2785-2787.
    [128]T.Y.Chu,T.S.Chin,C.H.Lin,J.M.Yao.Evidence of domain-wall pinning in W-doped(NdDy)(FeCo)B sintered magnets.J.Appl.Phys.,1994,76(10):6834-6836.
    [129]A.S.Kim,F.E.Camp.Effect of minor grain boundry additives on the magnetic properties of NdFeB magnets.IEEE Trans.Magn,,1995,31(6):3620-3622.
    [130]A.S.Kim,F.E.Camp.High performance NdFeB magnets(invited).J.Appl.Phys.,1996,79(8):5035-5039.
    [131]R.S.Mottram,A.J.Williams,I.R.Harris.The effects of blending additions of copper and cobalt to Nd_(16)Fe_(76)B_8 milled powder to produce sintered magnets.J.Magn.Magn.Mater.,2001,234(1):80-89.
    [132]A.Yah,X.P.Song,X.T.Wang.Effect of minor intergranular additives on microstructure and magnetic properties of Nd-Fe-B based magnets.J.Magn.Magn.Mater.,1997,169(1-2):193-198.
    [133]S.Yang,X.P.Song,X.H.Wang,Z.B.Sun,J.Sun.Effect of Al and Al/Mo addition on microstructure and magnetic properties of sintered Nd_(22)Fe_(71)B_7 magnets.Trans.Nonferrous Met Soc.China,2000,10(5):606-609.
    [134]R.S.Mottram,A.J.Williams,I.R.Harris.Blending additions of aluminium and cobalt to Nd_(16)Fe_(76)B_8milled powder to produce sintered magnets.J.Magn.Magn.Mater.,2000,222(3):305-313.
    [135]R.S.Mottram,A.J.Williams,I.R.Harris.Blending additions of cobalt to Nd_(16)Fe)(76)B_8 milled powder to produce sintered magnets.J.Magn.Magn.Mater.,2000,217(1-3):27-34.
    [136]W.H.Cheng,W.Li,C.J.Li,S.Z.Dong.The magnetic properties,thermal stability and microstructure of Nd-Fe-B/Ga sintered magnets prepared by blending method.J.Magn.Magn.Mater.,2001,234(2):274-278.
    [137]A.Yan,Z.M.Chen,X.P.Song,X.T.Wang.Effect of MgO additive on coercivity,thermal stability and microstructure of Nd-Fe-B magnets.J.Alloys Compd.,1996,239(2):172-174.
    [138]T.S.Zhao,Y.B.Kim,W.Y.Jeung.Magnetic properties and microstructure of NdFeB sintered magnets by the addition of Ag powder.IEEE Trans.Magn.,2000,36(5):3318-3320.
    [139]A.Yan,X.P.Song,M.D.Song,X.T.Wang.Magnetic and microstructural properties of sintered FeNdB-based magnets with W,Mo and Nb additions.J.Alloys Compd.,1997,257(1-2):273-277.
    [140]A.Yan,X.P.Song,X.T.Wang.Segregation of W in Nd-Fe-B magnets and its effects on coercivity.IEEE Trans.Magn.,2000,36(4):2033-2036.
    [141]J.Q.Zhou,M.G.Zhang.The effect of Mo addition on coercivity ofNdFeB sintered magnet prepared by blending method.Acta Metallurgica Sinica,2005,18(4):557-560.
    [142]J.F.Hu,Y.L.Liu,M.L.Yin,Y.Z.Wang,B.P.Hu,Z.X.Wang.Investigation of simultaneous enhancement of remanence and coercivity in Nd-Fe-B/Nb mixed-powder sintered magnets.J.Alloys Compd.,1999,288(1-2):226-228.
    [143]X.P.Song,S.Yang,X.H.Wang,Z.B.Sun,J.Sun.Effect of Copper and Titanium addition on microstructures and magnetic properties of Nd_(22)Fe_(71)B_7 based magnets.J.Rare Earths,2001,19(1):21-24.
    [144]A.Yan,X.P.Song,Z.M.Chen,X.T.Wang.Characterization of microstructure and coercivity of Nd-Fe-B magnets with Ti and Al or Cu addition.J.Magn.Magn.Mater.,1998,185(3):369-374.
    [145]M.H.Ghandehari.Reactivity of Dy_2O_3 and Tb_4O_7 with Nd_(15)Fe_(77)B_8 powder and the coercivity of the sintered magnets.J.Appl.Phys.,1986,48(8):548-550.
    [146]M.Doser,G.Keeier.Long-term stability of Fe-B-Nd-Dy alloys made by Dy_2O_3 additions.J.Appl.Phys.,1988,64(10):5311-5313.
    [147]L.Y.Li,J.H.Yi,Y.D.Peng,B.Y.Huang.The effect of compound addition Dy_2O_3 and Sn on the structure and properties of NdFeNbB magnets.J.Magn.Magn.Mater.,2007,308(1):80-84.
    [148]C.H.de Groot,K.H.J.Buschow,F.R.de Boer.Two-powder Nd_2Fe_(14)B magnets with DyGa addition.J.Appl.Phys.,1998,83(1):388-393.
    [149]T.S.Zhao,Y.B.Kim,W.Y.Jeung.Effect of FeGa_3 powder addition on the magnetic properties of NdFeB sintered magnets.IEEE Trans.Magn.,1999,35(5):3301-3303.
    [150]Z.M.Chen,A.Yan,X.T.Wang.Effects of intergranular additions of oxides on the coercivity,thermal stability and microstructure of Nd-Fe-B magnets.J.Magn.Magn.Mater.,1996,162(2-3):307-313.
    [151]A.Yan,Z.M.Chen,X.P.Song,X.T.Wang.The influence of MgO/Mg and Al_2O_3/Al additives on coercivity,thermal stability,and microstructure of Nd-Fe-B magnets.Mater.Res.Bull.,1996,31(10):1171-1177.
    [152]Z.M.Chen,A.Yan,X.T.Wang,G.C.Hadjipanayis.Improvement of magnetic properties and intergranular microstructure of Nd-Fe-B magnets by intergranular addition of MgO oxide.J.Appl.Phys.,1997,81(8):4456-4458.
    [153]W.J.Mo,L.T.Zhang,A.D.Shan,L.J.Cao,J.S.Wu,M.Komuro.Improvement of magnetic properties and corrosion resistance of NdFeB magnets by intergranular addition of MgO.J.Allays Compd.,2008,461(1-2):351-354.
    [154]W.J.Mo,L.T.Zhang,Q.Z.Liu,A.D.Shan,J.S.Wu,M.Komuro,L.P.Shen.Microstructure and corrosion resistance of sintered NdFeB magnet modified by intergranular additions of MgO and ZnO.J.Rare Earths,2008,26(2):268-273.
    [155]S.K.Chen,T.S.Chin,S.J.Heh,K.D.Lin.Coercivity enhancement of boron nitride doped Nd_(15)Fe_(77)B_8permanent magnets.IEEE Trans.Magn.,1990,26(5):2634-2636.
    [156]S.J.Heh,K.D.Lin,Y.M.Jein,F.D.King,F.L.Lee,T.S.Chin.Effects of nitride additions on the magnetic properties of R-Fe-B magnets(R=rare earths).IEEE Trans.Magn.,1990,26(5):2637-2639.
    [157]莫文剑,张澜庭,陈亮,单爱党,吴建生.添加Si_3N_4对烧结NdFeB的磁性能及抗腐蚀性能的影响.中国稀土学报,2007,25(5):588-591.
    [158]赵国仙,宋晓平,陈钟敏,阎阿儒,王笑天.WC对Nd-Fe-B烧结磁体的显微组织和磁性能的影响. 金属学报,1996,32(4):413-416.
    [159]H.Bala,S.Szymura,J.J.Wyslocki.Electrochemical corrosion resistance of Fe-Nd-B permanent magnets.J.Mater.Sci.,1990,25(1):571-574.
    [160]K.Turek,P.Liszkowski,H.Figiel.The kinetics of oxidation of Nd-Fe-B powders.IEEE Trans.Magn.,1993,29(6):2782-2784.
    [161]谢发勤,郜涛,邹光荣.NdFeB磁体组成相的电化学腐蚀行为.腐蚀科学与防护技术,2002,14(5):260-262.
    [162]L.Schultz,A.M.El-Aziz,G.Barkleit,K.Mummert.Corrosion behaviour of Nd-Fe-B Permanent magnetic alloys.Mater.Sci.Eng.A,1999,267(2):307-313.
    [163]刘卫强,岳明,张久兴,王公平,李涛.富钕相对烧结NdFeB磁体耐腐蚀性的影响.稀有金属材料与工程,2007,36(6):1066-1069.
    [164]D.W.Sott,B.M.Ma,Y.L.Liang,C.O.Bounds.The effects of average grain size on the magnetic properties and corrosion resistance of NdFeB sintered magnets.J.Appl.Phys.,1996,79(8):5501-5504.
    [165]H.Bala,S.Szymura,E.Owczarek,W.N.Wiechula.Corrosion behaviour of sintered Nd-(Fe,Al)-B magnets.Intermetallics,1997,5(7):493-495.
    [166]W.Fernengel,W.Rodewald,R.Blank,P.Schrey,M.Katter,B.Wall.The influence of Co on the corrosion resistance of sintered Nd-Fe-B magnets.J.Magn.Magn.Mater.,1999,196/197:288-290.
    [167]S Steyaert,J.M.L.Breton,J Teillet.Microstructure and corrosion resistance of Nd-Fe-B magnets containing additives.J.Phys.D,1998,31(13):1534-1547.
    [168]A.S.Kim,High Performance,Temperature Stable and Corrosion Resistant Nd-Fe-B Magnets,Proc.3rd.Int.Syrup on Physics of Magnetic Materials(ISPMM95 ) Seoul,Korea,1995,646-650.
    [169]B.Grieb.New corrosion resistant materials based on neodymium-iron-boron.IEEE Trans.Magn.,1997,33(5):3904-3906.
    [170]A.S.Kim,F.E.Camp,E.J.Dulls.Effect of oxygen,carbon,and nitrogen contents on the corrosion resistance of Nd-Fe-B magnets.IEEE Trans.Magn.,1990,26(5):1936-1938.
    [171]D.J.Blackwood,B.Balakrisnan,Y.Z.Huang,C.K.Tan,Influence of the chemical composition of the plating solution on the ability of nickel coating to protect Nd_2Fe_(14)B magnets against corrosion,J.Magn.Magn.Mater.,2001,223(2):103-111.
    [172]Z.Chen,A.Ng,J.Z.Yi,X.F.Chen.Multi-layered electroless Ni-P coatings on powder-sintered Nd-Fe-B permanent magnet.J.Magn.Magn.Mater.,2006,302(1):216-222.
    [173]谢发勤,马宗跃.离子镀铝的Nd-Fe-B永磁体性能研究.磁性材料及器件,1995,26(1):7-8.
    [174]F.T.Cheng,H.C.Man,W.M.Chan,C.W.Cheng,W.O.Chan.Corrosion protection of Nd-Fe-B magnets by bismaleimide coating,J.Appl.Phys.,1999,85(8):5690-5692.
    [175]高令远,范桂荣.永磁材料NdFeB有机涂层的研究.材料保护,1996,29(2):9-10.
    [176]龚捷,杨仕清,彭斌,张万里,王豪才.NdFeB稀土永磁材料双层镀NiP/Cr.材料工程,2000,2:28-30.
    [177]林万舟,宋来州,李向阳.烧结NdFeB永磁体表面Ni-P/TiO_2复合膜的耐腐蚀性能.材料保护,2008,41(11):53-57.
    [178]J.M.Cadogan,J.M.D.Coey.Hydrogen absorption and desorption in Nd_2Fe_(14)B.Appl,Phys.Lett.,1986,48(6):442-444.
    [179]何水校.稀土永磁制粉设备--气流磨闭环系统.磁性材料及器件,1990,21(4):48-51.
    [180]X.L.Liu,S.Z.Zhou.Grain growth behavior in sintered Nd-Fe-B magnets,J.Rare Earths,2007,25(3):329-335.
    [181]闫宝珠.质量与密度测量不确定度评定.北京:中国计量出版社,2002.
    [182]孙秋霞,材料腐蚀与防护.北京:冶金工业出版社,2001.
    [183]王吉会,郑俊萍,刘家臣,黄定海.材料力学性能.天津:天津大学出版社,2006.
    [184]王成国,丁洪太,侯绪荣.材料测试方法.上海:上海交通大学出版社,1994.
    [185]范雄.金属X射线学.北京:机械工业出版社.1996.
    [186]S.Hirosawa,S.J.Mino,H.Tomizawa.Improved corrosion resistance and magnetic properties of Nd-Fe-B-type sintered magnets with Mo and Co.J.Appl.Phys.,1991,69(8):5844-5846.
    [187]D.Brown,B.M.Ma,Z.M.Chen.Developments in the processing and properties of Nd-Fe-B-type permanent magnets,at.Magn.Magn.Mater.,2002,248(3):432-440.
    [188]李正,何叶青,胡伯平,王震西.烧结Nd-Fe-B中的热力学影响.物理学报,2005,54(11):5400-5404.
    [189]E.McCafferty.Validation of corrosion rates measured by the Tafel extrapolation method.Corr.Sci.,2005,47(12):3202-3215.
    [190]A.A.El-moneim,A.Gebert.Electrochemical characterization of galvanically coupled single phases and nanocrystalline NdFeB-based magnets in NaCl solutions.J.Appl.Electrochem.,2003,33(9):795-805.
    [191]I.Gurappa.Corrosion characteristics of permanent magnets in acidic environments.J.Alloys Compd.,2003,360(1-2):236-242.
    [192]G.W.Warren,G.Gao,O.Li.Corrosion of NdFeB permanent magnet materials.J.Appl.Phys.,1991,70(10):6609-6611.
    [193]黄建中,左禹.材料的耐蚀性和腐蚀数据.北京:化学工业出版社,2003.
    [194]G.L.Yan,A.J.Williams,J.P.G.Farr,I.R.Harris.The effect of density on the corrosion of NdFeB magnets.J.Alloys Compd.,1999,2920-2):266-274.
    [195]D.W.Scott,B.M.Ma,Y.L.Liang,C.O.Bounds.The effects of average grain size on the magnetic properties and corrosion resistance of NdFeB sintered magnets.J.Appl.Phys.,1996,79(8):5501-5504.
    [196]H.T.Kim,Y.B.Kim,J.W.Jeon,I.H.Jang,G.A.Kapustin,H.S.Kim.High-performance nanocrystalline NdFeB magnets by CAPA process.J.Magn.Magn.Mater.,2006,304(1 ):e240-e242.
    [197]Y.Hu,I.P.Jones,M.Windows,I.R.Harris.Zn diffusion induced precipitation along grain boundaries in Zn-coated NdFeB magnets.J.Magn.Magn.Mater.,2003,2610-2):13-20.
    [198]周寿增,唐伟忠,王润.烧结NdFeB永磁合金的边界显微结构与磁硬化.金属学报,1990,26(4):B290-B294.
    [199]K.Tokuhara,S.Hirosawa.Corrosion resistance of Nd-Fe-B sintered magnets.J.Appl.Phys.,1991,69(8):5521-5523.
    [200]J.Jacobson,A.Kim.Oxidation behavior of Nd-Fe-B magnets.J.Appl.Phys.,1987,81(8):3763-3765.
    [201]A.S.Kim,F.E.Camp,T.Lizzi.Hydrogen induced corrosion mechanism in NdFeB magnets,J.Appl.Phys.,1996,79(8):4840-4843.
    [202]M.Katter,L.Zapf,R.Bland,W.Fernengel,W.Rodewald.Corrosion mechanism of RE-Fe-Co-Cu-Ga-Al-B magnets.IEEE Trans.Magn.,2001,37(4):2474-2476.
    [203]G.L.Yan,P.McGuiness,J.P.G.Farr,I.R.Harris.Environmental Degradation of NdFeB Magnets.J.Alloys & Compds.,in press.
    [204]D.F.Cygan,M.J.McNallan.Corrosion of NdFeB permanent magnets in humid environments at temperatures up to 150℃.J.Magn.Magn.Mater.,1995,139(1-2):131-138.
    [205]A.S.Kim,F.E.Camp.The role of oxygen for improving magnetic properties and thermal stability of sintered(Nd,Dy)(Fe,Co)B magnets.1995,31(6):3656-3658.
    [206]S.Besenicar,B.Saje,G.Drazic,J.Holc.The influence of ZrO_2 addition on the microstructure and the magnetic properties of Nd-Dy-Fe-B magnets.J.Magn.Magn.Mater.,1992,104-107(2):1175-1178.
    [207]I.Barin,G.Platzki,Thermochemical Data of Pure Substances.Weinheim:VCH,1995.
    [208]金义范.金玳.庄允迪.物理化学.北京:高等教育出版社,1997.
    [209]X.K.Sun,G.F.Zhou,Y.C.Chuang,R.Gr(o|¨)ssinger,H.R.Kirchmayr.Microstructure and coercivity of (Nd,Dy)-(Fe,Co)-B sintered permanent magnets containing a small addition of niobium and silicon.J.Magn,Magn.Mater.,1991,96(1-3):197-205.
    [210]谢发勤,郜涛,马宗耀,邹光荣.NdFeB永磁合金电化学腐蚀行为研究.腐蚀与防护,2001,22(9):381-383.
    [211]M.Komuro,Y.Satsu,Y.Enomoto,H.Koharagi.High electrical resistance hot-pressed NdFeB magnet for low loss motors.Appl.Phys.Lett.,2007,91(10):102503-1-3.
    [212]F.R.Boer,D.G.Perrifor.Cohesion in metals.Netherlands:Elsevier Science Publisher,1988.
    [213]B.S.Murty,S.Ranganathan,R.M.Mohan.Solid state amorphization in binary Ti-Ni,Ti-Cu and ternary Ti-Ni-Cu system by mechanical alloying.Mater Sci Eng A,1992,149(2):231-240.
    [214]A.Takeuchi,A.Inoue.Classification of bulk metallic glasses by atomic size difference,heat of mixing and period of constituent elements and its application to characterization of the main alloying element.Mater.Trans.,2005,46(12):2817-2829.
    [215]傅献彩,沈文霞,姚天扬.物理化学.北京:高等教育出版社,1990.
    [216]周寿增,张瑾,马德青,高茂林.添加Dy和Dy_2O_3的烧结NdFeB系永磁体的显微结构与磁硬化.金属学报,1992,28(3):B115-B120.
    [217]胡祖炽,林源渠.数值分析.北京:高等教育出版社,2001.
    [218]M.R.Corfield,I.R.Harris,A.J.Williams.Influence of oxygen content on grain growth in Pr-Fe-B/Nd-Fe-B sintered magnets.J.Alloys Compd.,2008,463(1-2):180-188.
    [219]C.Zener.Grains,phases,and interfaces:an interpretation of microstructure.Trans.Am.Inst.Min.Metall.Eng.,1948,175:15-51.
    [220]R.Ramesh,K.Srikrishna.Magnetization reversal in nucleation controlled magnets.I.Theory.J.Appl.Phys.,1988,64(11):6406-6415.
    [221]王占勇.烧结NdFeB的显微组织分析及高矫顽力烧结NdFeB的研制[硕士学位论文].天津:河北工业大学,2002,34-35.
    [222]R.W.Armstrong.The influence of polycrystal grain size on several mechanical properties of materials.Metall.Trans.,1970,1(5):1169-1176.
    [223]M.Okada,S.Sugimoto,C.Ishizaka,T.Tanaka,M.Homma.Didymium-Fe-B sintered permanent magnets.J.Appl.Phys.,1985,57(1):4146-4148.
    [224]W.Z.Tang,S.Z.Zhou,R.Wang.Preparation and microstructure of La-containing R-Fe-B permanent magnets.J.Appl.Phys.,1989,65(8):3142-3145.
    [225]K.W.Lay.Grain Growth in UO_2-Al_2O_3 in the Presence of a Liquid Phase.J.Am.Ceram.Soc.,1968,51(7):373-376.
    [226]朱明刚,潘伟,李卫.Dy与Co对HDDR粘结磁体的温度稳定性与磁性能的影响.物理学报,2002,51(7):1608-1611.
    [227]R.Ramesh.A microstructure based magnetization reversal model in sintered Fe-Nd-B magnets.I.J.Appl.Phys.,1990,68(11):5767-5771.
    [228]A.Fukuno,K.Hirose,T.Yoneyama.Coercivity mechanism of sintered NdFeB magnets having high coercivities.J.Appl.Phys.,1990,67(9):4750-4752.
    [229]W.Gong,Q.S.Li,L.Yin.Temperature feature of NdDyFeB magnets with ultrahigh coercivity.J.Appl.Phys.,1991,69(8):5512-5514.
    [230]张绍英.关于Nd-Fe-B型磁体热稳定性的研究现状与动态.1991,12(3):53-60.
    [231]K.H.J.Buschow.New Developmnets in Hard Magnetic Materials.Rep.Prog.Phys.,1991,54(9):1123-1213.
    [232]A.S.Kim.Design of high temperature permanent magnets.J.Appl.Phys.,1997,81(8):5609-5611.

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