Nd-Fe-B永磁材料氢脆机理与阻氢涂层研究  

Hydrogen Embrittlement Mechanism and Hydrogen Resistance Coatings of Nd-Fe-B Magnet

作　　者：蒋洪川[1] 杨仕清[1] 张万里[1] 彭斌[1] 张文旭[1] 王豪才[1] 

机构地区：[1]电子科技大学信息材料工程学院,四川成都610054

出　　处：《稀土》2002年第1期27-31,共5页Chinese Rare Earths

基　　金：国防预研项目资助 (项目编号 :12 .4.2 .2 )

摘　　要：本文利用三维 Mobius反演变换得到了金属 Nd原子间的相互作用势和 H原子间的相互作用势 ,利用组合规则得到了 Nd- H原子间的相互作用势 ,进而利用正则系统分子动力学算法研究了在一定加载应力强度因子下氢在 Nd晶体中的行为 ,模拟结果表明 ,H在 Nd晶体裂尖富集成许多氢原子团簇或氢气团簇 ,这在一定程度上解释了 Nd- Fe- B磁体中的氢爆现象 ,进而为 Nd- Fe- B阻氢涂层工艺提供理论参考 ,达到在原子分子水平上设计新型阻氢涂层的目的。对 Nd- Fe- B阻氢涂层的制备进行了实验研究 ,利用厚膜烧结方法在 Nd- Fe- B磁体表面涂覆银及高分子聚合物涂层 ,高压充氢实验结果表明 ,在 10 MPa、2 5℃的氢环境中 ,磁体充氢 178分钟未粉碎 ,最长可达2 88分钟 ,充氢后的磁体磁性能没有变化。另外 ,对 γ-辐照前后涂覆涂层的磁体进行了磁性能、充氢及尺寸测试 ,实验结果表明 ,涂覆涂层的磁体 γ-辐照前后磁性能。In this paper,for hydrogen resistance of Nd Fe B magnet,theoretically,the 3-D Mobius inversion method is used to get the pair-potentials of Nd atoms and H atoms and combination rules are used to get the potential between Nd and H atoms. The motion of hydrogen in the Nd crystal is studied by canonical ensemble molecular dynamics under certain stress.The results show that the H atoms come together around the crack tip.H atoms or H 2 molecular clusters with different sizes are formed.Therefore,the hydrogen embrittlement observed in the Nd Fe B magnet can be partly explained.So this results can be used for theoretical reference of Nd Fe B hydrogen resistance coating fabrication,and then new hydrogen resistance coatings can be designed on the base of atoms and molecular level.Experimentally,the fabrication of Nd Fe B hydrogen resistance coatings is studied.The thick-coating method is used to spread Ag and polymer on Nd Fe B magnet surface.The results of high hydrogen pressure experiments show that the magnet can stand 10MPa hydrogen pressure (25℃)within 178-288 minutes without magnet embrittlement,and the performances of Nd Fe B magnet do not change.In addition,the performances,hydrogen resistance and sizes of magnet are measured before and after γ-irradiation.The results show that the performances,hydrogen resistance and sizes of magnet with coatings do not change before and after γ-irradiation.

关 键 词：分子动力学 阻氢涂层 氢脆 Γ-辐照 ND-FE-B永磁材料 钕铁硼永磁材料 磁性能 

分 类 号：TM273[一般工业技术—材料科学与工程]