Abstract：Zinc-Cobalt (Zn-Co) alloy coating was deposited on sintered NdFeB magnet by eletroplating method in the chloride eletrolyte, and the electroplating parameters were optimized. The microstructure, corrosion resistance and mechanical properties of the samples were studied by neutral salt spray test (NSS) and scanning electron microscopy (SEM), potentiodynamic polarization curves and adhesion test. The results showed that the optimized parameters for preparing Zn-Co alloy coated NdFeB magnets are additive agent concentration of 15 ml/L, PH value of 4, electroplating temperature of 25℃ and current density of 1 A/dm-2. The NSS time of passivated Zn-Co NdFeB magnets can reach 120 h. The structure alloy coating is dense, and fills the inherent defects of NdFeB magnets effectively, laying a good foundation for the formation of dense passivation film. Surface of the passivated Zn-Co alloy coating is smooth and bright, and the corrosion current density is one order of magnitude lower than that of Zn coating, which means the better corrosion resistance of the Zn-Co alloy coating.
[1]Sagawa M.Fujimura S,Togawa N.,Yamamoto H.,Matsuura Y.,New material for permanent magnets on a base of Nd and Fe (invited)[J].Journal of Applied Physics, 1984, 55(6):2083-2087
[2] 罗阳.全球NdFeB磁体产业变化与发展的25年[J].磁性材料及器件, 2008, 39(6):9-18
[3]Luo Yang.Twenty Five Years Development of Global NdFeB Magnet Industry[J].Journal of Magnetic Materials and Devices, 2008, 39(6):9-18
[4] Hu Boping.[J].Journal of Magnetic Materials and Devices, 2012, 43(6):1-19
[5] Huang Youlin, Liu Zhongwu, Zhong XC, Yu HY,. Diffusion of Nd-rich phase in the spark plasma sintered and hot deformed nanocrystalline NdFeB magnets[J].Journal of Applied Physics, 2012, 111(3):033913-033913-4
[6] Constantinescu C, Patroi E, Codescu M, Dinescue M,. Effect of nitrogen environment on Nd-Fe-B thin films grown by radio frequency plasma beam assisted pulsed laser deposition[J].Materials Science & Engineering B, 2013, 178(4):267-271
[7] Song YW, Zhang H, Yang HX, Song ZL,. A comparative study on the corrosion behavior of NdFeB magnets in different electrolyte solutions[J].Materials & Corrosion, 2008, 59(10):794-801
[8] Wang Y, Deng Y, Ma Y, Gao F,. Improving adhesion of electroless Ni-P coating on sintered NdFeB magnet[J].Surface and Coatings Technology, 2011, 206(6):1203-1210
[9]李金龙，冒守栋，孙科沸，宋振纶.氮分压对 表面直流磁控溅射沉积防护涂层结构和性能的影响[J].中国表面工程, 2010, 23(3):80-83
[10]Li Jinlong, Mao Shoudong, Sun Kefei, Song Zhenlun,. Effect of Nitrogen Partial Pressure on Structure and Properties of AlN/Al Protective Coatings on NdFeB by DC Magnetron Sputtering[J].China Surface Engineering, 2010, 23(3):80-83
[11] 杨哲龙，李秀云，李文良.Zn- Co合金镀层耐蚀性研究[J].材料保护, 1994, 27(5):7-9
[12]Yang Zhelong, Li Xiuyun, Li Wenliang, .Research on the anti-corrosion performance of Zn-Co alloy coatings[J].Materials Protection, 1994, 27(5):7-9
[13] 李拨，王成彪，王向东，陈小平，彭楠.烧结钕铁硼电镀锌铁合金工艺与耐蚀性能[J].稀有金属材料与工程, 2015, 44(1):174-178
[14]Li Ba, Wang Chengbiao, Wang Xiangdong, Chen Xiaoping, Peng Nan, .Technology and Corrosion Resistance of Electrodeposited Zn-Fe Alloys onto Nd-Fe-B Sintered Magnets[J].Rare Metal Materials and Engineering, 2015, 44(1):174-178
[15] Cao R, Zhu L, Liu H, Yang W, Li W.The effect of silica sols on electrodeposited zinc coatings for sintered NdFeB[J].Rsc Advances, 2015, 5(126):104375-104385
[16]Song LZ, Wang YN, Lin WZ, Liu Q.Primary investigation of corrosion resistance of Ni-PTiO2,composite film on sintered NdFeB permanent magnet[J].Surface and Coatings Technology, 2008, 202(21):5146-5150
[17] 李光玉，牛丽媛，张苧心.锌钴合金防腐蚀镀层的研究与应用[J].化工新型材料, 2002, 30(10):39-42
[18]Li Guangyu, Liu Liyuan, Zhang Ningxin.Research and application of zinc-cobalt alloy plating film for anticorrosion[J].New Chemical Materials, 2002, 30(10):39-42
[19]Wang Y, Deng Y, Ma Y, Gao F.Improving adhesion of electroless Ni-P coating on sintered NdFeB magnet[J].Surface and Coatings Technology, 2011, 206(6):1203-1210
[20]Zhang PJ, Liu JQ, Xu GQ, Yi XF, Chen JW, Wu YC.Anticorrosive property of Al coatings on sintered NdFeB substrates via plasma assisted physical vapor deposition method[J].Surface and Coatings Technology, 2015, 282(1):86-93
[21]彭楠.NdFeB永磁体表面电镀Zn-Fe合金工艺的研究[J].昆明理工大学, 2013, :-
[22]Peng Nan.Research on the electroplating technology of Zn-Fe alloy on the surface of NdFeB magnets[J].Kunming University of Science and Technology, 2013, :-
[23] Zhang PJ, Xu GQ, Liu JQ, Yi XF, Wu YC, Chen JW.Effect of pretreating technologies on the adhesive strength and anticorrosion property of Zn coated NdFeB specimens[J].Applied Surface Science, 2016, 363(1):499-506
[24]Wang N, Cheng KQ, Wu H, Wang CQ, Wang C, Wang FH.Effect of nano-sized mesoporous silica MCM-41 and MMT on corrosion properties of epoxy coating[J].Progress in Organic Coatings, 2012, 75(4):386-391
[25]张鹏杰，吴玉程，曹玉杰，徐光青，刘家琴，衣晓飞，陈静武.前处理工艺对表面真空蒸镀薄膜结构及性能的影响[J].中国表面工程, 2016, 29(4):49-59
[26]Zhang PJ, Wu YC, Cao YJ, Xu GQ, Liu JQ, Yi XF, Chen JW.Effects of Pretreatment Technologies on Structure and Properties of Al Coatings on Sintered NdFeB Substrates via Vacuum Evaporation[J].China Surface Engineering, 2016, 29(4):49-59
[27]Yang H, Mao S, Song Z.The effect of absorbed hydrogen on the corrosion behavior of sintered NdFeB magnet[J].Materials and Corrosion, 2015, 63(4):292-296
[28] Xu JL, Zhong ZC, Huang ZX, Luo JM.Corrosion resistance of the titania particles enhanced acrylic resin composite coatings on sintered NdFeB permanent magnets[J]. Journal of Alloys and Compounds, 2013, 570(1):28-33
2020, Vol. 27 