真空热处理提高烧结钕铁硼镀Cu层结合力的研究  

Improvement of Adhesive Strength of Cu Film on Nd-Fe-B by Vacuum Annealing

作　　者：肖松 杨杰 张青科 杨丽景 宋振纶 李谋成[1] XIAO Song;YANG Jie;ZHANG Qing-ke;YANG Li-jing;SONG Zhen-lun;LI Mou-cheng(School of Materials Science and Engineering,Shanghai University,Shanghai 200072,China;Key laboratory of Magnetic Materials and Devices,Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences,Ningbo 315201,China)

机构地区：[1]上海大学材料科学与工程学院,上海200072 [2]中国科学院宁波材料技术与工程研究所中国科学院磁性材料与器件重点实验室,浙江宁波315201

出　　处：《表面技术》2019年第10期276-284,共9页Surface Technology

摘　　要：目的提高烧结钕铁硼表面镀Cu膜层结合力,改善可焊性,进一步制备生物友好的强耐蚀性防护薄膜。方法采用磁控溅射技术在钕铁硼表面制备约7μm厚的Cu膜,研究热处理温度和时间对Cu/NdFeB界面组织、膜基结合力和样品磁性能的影响,选取最优化热处理样品电镀约2μm厚的Sn膜,再于280℃在其表面焊接Au片,评估其可焊性。结果500℃热处理样品的Cu膜与基体间发生了明显扩散,扩散深度及结合力随时间延长而增加。热处理2 h样品的膜基结合力由处理前的11.0 MPa提高至31.5 MPa,膜基分离位置发生在磁体亚表面层,矫顽力、剩磁和最大磁能积等磁性能无显著下降。进一步镀Sn后,在其表面焊接的Au层与Cu膜层基体冶金结合良好,耐腐蚀性能优异。700℃热处理样品的Cu膜与基体间扩散过快,易造成Cu膜消失及钕铁硼基体表面损伤。结论真空热处理温度和时间对Cu/钕铁硼界面组织有根本性影响,通过适宜的热处理可大幅提高磁控溅射的Cu膜与烧结钕铁硼之间的膜基结合力,同时不明显降低磁性能,可采用焊接方法在热处理后的Cu膜表面制备结合力高、长效耐蚀且生物友好的防护薄膜。The work aims to increase the adhesive strength of Cu film on sintered NdFeB magnet substrate,improve the solderability of magnet and further prepare the bio-friendly protective film with strong anti-corrosion property.A Cu film with a thickness of about 7μm was prepared on the NdFeB by magnetron sputtering.The effect of annealing temperature and time on the interfacial structure and adhesive strength of Cu/NdFeB and the magnetic properties of the samples were investigated.The optimized annealed sample was selected to deposit a 2μm Sn layer by electrodeposition and then an Au flake was soldered to the surface at 280℃to evaluate the solderability.Significant diffusion occurred between the Cu film and the NdFeB substrate when the sample was annealed at 500℃and the diffusion depth and adhesive strength increased as the annealing time extended。The Cu/NdFeB adhesive strength of the sample annealed for 2 h increased to 31.5 MPa from 11.0 MPa,the separation occurred in the subsurface layer of the magnet,and the magnetic properties such as coercivity,remanence and maximum magnetic energy product did not decrease significantly.After Sn was deposited,the soldered Au had good metallurgical bonding with the Cu film and excellent anticorrosion property.For the sample annealed at 700℃,the quick diffusion between Cu film and substrate could easily cause the disappearance of Cu film and damage of the NdFeB substrate.The vacuum annealing temperature and time have fundamental effect on the interfacial structure of Cu/NdFeB and suitable annealing can greatly improve the adhesive strength between the magnetron-sputtered Cu film and the sintered NdFeB.At the same time,the magnetic properties have no significant decrease.A high adhesive,long-lasting anti-corrosive and bio-friendly protective film can be prepared on the surface of the heat-treated Cu film by soldering.

关 键 词：烧结钕铁硼 磁控溅射 CU膜 扩散焊接 结合力 耐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]