热变形工艺对各向异性NdFeB永磁体显微结构和磁性能的影响
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摘要
采用热压-热变形法制备各向异性NdFeB磁体,通过正交实验研究了热变形温度、变形量以及变形速率对磁体磁性能及显微结构的影响。结果表明,随变形温度、变形量、变形速率的增高增大,磁体剩磁Br及最大磁能积(BH)max增高,当变形温度升高至700℃、变形量增大到65%、以0.045mm/s的速率变形时,磁体获得最佳磁性能,(BH)max达360kJ/m3(45MGOe),同时主相NdFeB晶粒由最初的球状晶、沿垂直于压力方向长大转变为片状晶,晶粒取向度增高;当变形温度、变形量过高或变形速率过低时,磁体中将会出现异常长大晶粒,使磁性能恶化。
Anisotropic NdFeB magnets have been prepared by hot-pressing/hot-deforming.Orthogonal experimental method was utilized to investigate the effect of temperature,degree and rate of deformation on the microstructure and magnetic properties of the magnets.The result shows that with increasing hot deforming temperature,degree rate,the magnets’ Brand(BH)maximprove.At deforming temperature of 700℃,rate of 0.045mm/s and degree of 65%,the hot deformed magnet was prepared with optimal(BH)maxof 360kJ/m3(45MGOe).The morphology of main phase grains transform from sphere to flake,and the alignment degree of enhances.For too high deforming temperature,degree or too low deforming rate,abnormal growth of the grain occurs,resulting in deterioration of magnetic properties.
Anisotropic NdFeB magnets have been prepared by hot-pressing/hot-deforming.Orthogonal experimental method was utilized to investigate the effect of temperature,degree and rate of deformation on the microstructure and magnetic properties of the magnets.The result shows that with increasing hot deforming temperature,degree rate,the magnets’ Brand(BH)maximprove.At deforming temperature of 700℃,rate of 0.045mm/s and degree of 65%,the hot deformed magnet was prepared with optimal(BH)maxof 360kJ/m3(45MGOe).The morphology of main phase grains transform from sphere to flake,and the alignment degree of enhances.For too high deforming temperature,degree or too low deforming rate,abnormal growth of the grain occurs,resulting in deterioration of magnetic properties.
引文
[1]刘湘涟,周寿增.Nd-Fe-B磁体烧结过程晶粒长大行为的研究[J].中国稀土学报,2006,24(5):580-585.
[2]Uestuener K,Katter M,Rodewald W,et al.Dependenceof the mean grain size and coercivity of sintered Nd-Fe-Bmagnets on the initial powder particle size[J].IEEETrans Magn,2006,42(10):2897-2899.
[3]李卫,朱明刚.各向异性热压稀土永磁体的热变形机制及微磁结构研究[J].中国工程学报,2011,13(10):4-12.
[4]王公平,岳明,张久兴.放电等离子烧结制备高性能NdFeB永磁材料[J].中国有色金属学报,2006,16(3):459-463.
[5]高汝伟,李华,周寿增,等.取向磁场对烧结Nd-Fe-B永磁体性能的影响[J].科学通报,1994,39(4):312-315.
[6]Lee R W.Hot pressed neodymium iron boron magnets[J].Appl Phys Lett,1985,46(8):790-791.
[7]Brown D N,Smith B,Ma B M,et al.The dependence ofmagnetic properties and hot workability of rareearh-iron-boride magnets upon composition[J].IEEETrans Magn,2004,40(4):2895-2897.
[8]Yue M,Tian M,Zhang J X,et al.Microstructure andmagnetic properties of anisotropic Nd-Fe-B magnetsproduced by spark plasma sintering technique[J].MaterScie&Engi B,2006,131(1-3):18-21.
[9]易鹏鹏,林旻,王会杰,等.热压过程对热变形钕铁硼磁体磁性能影响的研究[J].稀有金属材料与工程,2009,38(1):576-578.
[10]Hu Z H,Liu Y,Li J,et al.Enhanced magnetic propertiesin Nd-Fe-B magnets prepared by spark plasma sinteringvia die-upsetting process[J].J Rare Earths,2011,29(7):660-663.
[11]刘世强,李东,黄美清,等.各向异性纳米晶复合稀土磁体的研制[J].磁性材料及器件,2007,38(4):1-10.
[12]张成军,纪朝辉,董广强.实验设计与数据处理及其应用[M].哈尔滨:哈尔滨工业大学出版社,2000:92-137.
[13]Ma Y L,Liu Y,Li J,et al.The microstructure andmagnetic properties of bulk magnets Nd14-xFe76+xCo3Zr1B6(x=0,0.5,1)prepared by spark plasma sintering[J].JRare Earths,2009,27(6):1023-1026.
[14]Mishra R K,Brewer E G..Grain growth and alignment inhot deformed Nd-Fe-B magnets[J].J Appl Phys,1988,63(8):3528-3530.
[15]Yoshida Y,Kasai Y,Watanabe T,et al.Hot workability ofmeltspun NdFeCoB magnets[J].J Appl Phys,1991,69(8):5841-5843.
[2]Uestuener K,Katter M,Rodewald W,et al.Dependenceof the mean grain size and coercivity of sintered Nd-Fe-Bmagnets on the initial powder particle size[J].IEEETrans Magn,2006,42(10):2897-2899.
[3]李卫,朱明刚.各向异性热压稀土永磁体的热变形机制及微磁结构研究[J].中国工程学报,2011,13(10):4-12.
[4]王公平,岳明,张久兴.放电等离子烧结制备高性能NdFeB永磁材料[J].中国有色金属学报,2006,16(3):459-463.
[5]高汝伟,李华,周寿增,等.取向磁场对烧结Nd-Fe-B永磁体性能的影响[J].科学通报,1994,39(4):312-315.
[6]Lee R W.Hot pressed neodymium iron boron magnets[J].Appl Phys Lett,1985,46(8):790-791.
[7]Brown D N,Smith B,Ma B M,et al.The dependence ofmagnetic properties and hot workability of rareearh-iron-boride magnets upon composition[J].IEEETrans Magn,2004,40(4):2895-2897.
[8]Yue M,Tian M,Zhang J X,et al.Microstructure andmagnetic properties of anisotropic Nd-Fe-B magnetsproduced by spark plasma sintering technique[J].MaterScie&Engi B,2006,131(1-3):18-21.
[9]易鹏鹏,林旻,王会杰,等.热压过程对热变形钕铁硼磁体磁性能影响的研究[J].稀有金属材料与工程,2009,38(1):576-578.
[10]Hu Z H,Liu Y,Li J,et al.Enhanced magnetic propertiesin Nd-Fe-B magnets prepared by spark plasma sinteringvia die-upsetting process[J].J Rare Earths,2011,29(7):660-663.
[11]刘世强,李东,黄美清,等.各向异性纳米晶复合稀土磁体的研制[J].磁性材料及器件,2007,38(4):1-10.
[12]张成军,纪朝辉,董广强.实验设计与数据处理及其应用[M].哈尔滨:哈尔滨工业大学出版社,2000:92-137.
[13]Ma Y L,Liu Y,Li J,et al.The microstructure andmagnetic properties of bulk magnets Nd14-xFe76+xCo3Zr1B6(x=0,0.5,1)prepared by spark plasma sintering[J].JRare Earths,2009,27(6):1023-1026.
[14]Mishra R K,Brewer E G..Grain growth and alignment inhot deformed Nd-Fe-B magnets[J].J Appl Phys,1988,63(8):3528-3530.
[15]Yoshida Y,Kasai Y,Watanabe T,et al.Hot workability ofmeltspun NdFeCoB magnets[J].J Appl Phys,1991,69(8):5841-5843.