J.Q. Zhou
,
M.G. Zhang
金属学报(英文版)
Alloy modification, accompanying with proper heat treatment, is commonly used to improve the thermal stability of NdFeB magnet. Traditional alloy modification is performed through melting process with alloy elements to form the multi-alloy. In doing so, these alloy elements not only are introduced into the inter-granular boundaries, but partly into the main phase, thus decreasing to some extent the magnetism of the main phase. In this paper, the blending method is used to prepare the Nd22Fe71B7/Mo sintered magnet, and its magnetic properties and microstructures are investigated. The results show that by adding 1.5% (mass fraction) Mo, the intrinsic coercivity iHc of the magnet reaches the maximum value of 1719.36KA/m,while continually increasing the amount of Mo has a less effect on iHc. Microstructures analysis indicates that Mo-free Nd-Fe-B magnet has not uniform grains in size, while that with Mo element has uniform grains in size and smooth grain boundaries. Experiments show that after the NdFeB magnet is sintered at 1273K and annealed at 873K, the added Mo element could prevent the equilibrium transformation between the main phase and Nd-rich phase, thus resulting in the precipitation of fine second main phase (Nd2Fe14-xMoxB) from the main phase boundaries, preventing the nucleation and expansion of anti-magnetic domain, and enhancing the coercivity.
关键词:
Nd-Fe-B magnet
,
null
,
null
HUANG Gangxiang XU Qingzhen GAO Huimin YU Shanfu HUA Hongci WANG Geya Shanghai Iron and Steel Research Institute
,
Shanghai
,
200940
,
China.Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
200050
,
China.
材料科学技术（英文）
The microstructures of melt-spun Nd_135- Fe_81.74B4.76 ribbons have been investigated by means of X-ray diffraction,Mossbauer spectroscopy and HREM.Experimental results show that optimal magnetic properties of the bond- ed magnet can be obtained by melt-spun alloys at wheel velocity of 24m/s,the microstructure of which was single phase Nd_2Fe_(14)B crystallites,and no other phases,such as Nd-rich,B-rich or x-Fe phase,were present.It is considered that the high intrinsic coercivity ~iH_c can be attributed to the sin- gle-domain behaviour of Nd_2Fe_(14)B crystallite phase.
关键词:
coercivity
,
null
陈金清
,
段敏
,
吴美浩
,
黎龙贵
,
黄亚祥
,
黄彬
,
黄超
有色金属工程
doi:10.3969/j.issn.2095-1744.2016.06.001
研究了在磁体制备过程中添加Al2O3粉体对(PrNd)31(AlCoCuGaZr)1.55 B0.98 Fe合金磁体密度、微观结构和磁性能的影响.结果表明,随着Al2O3粉末添加量的增加,磁体密度和矫顽力都呈先上升后下降趋势,剩磁与最大磁能积缓慢下降.Al2O3粉末添加量为0.1％时,磁体密度提升0.01 g/cm3,继续添加,磁体密度开始下降;当Al2O3添加量为0.2％时,磁体矫顽力显著提升(提高5％),综合磁性能最佳.显微组织分析结果表明,适量添加Al203可使磁体晶粒平均尺寸减小,能改善磁体显微组织,促进磁体致密化.此外,分布在晶界中的Al2O3/RE2O3能够钉扎晶界,细化晶粒,使晶粒尺寸均匀,提高磁体磁性能.
关键词:
Al2O3
,
烧结钕铁硼磁体
,
矫顽力
,
微观组织
,
磁性能
罗阳
,
张宁
金属学报
<正> 为揭示快淬热压磁体热应变织构产生的根源,我们对合金机械性能随温度的变化进行了系统研究。前文报道了Nd-Fe-B磁体的热膨胀和硬度随温度的变化,本文则着重报道在室温到800℃温区内,Nd-Fe-B磁体的杨氏模量随温度的变化,以展示晶体刚度各向异性和塑性流变特性对热应变织构形成的可能贡献。 一般而言,合金的杨氏模量是结构不敏感的参量,即它与合金内部显微组织以及合金成分的微调无关。它主要反映合金内部原子之间的键合,故具
关键词:
钕铁硼磁体
,
Young's modulus
,
thermal strain
