Sintered neodymium (NdFeB) magnet material is highly vulnerable to corrosion. To solve this problem, three kinds of structures (dark nickel, bright nickel, and multilayered nickel) were produced efficiently and quickly by using jet electrodeposition technology. The structure and microstructure of the coatings were analysed by X-ray diffraction and field-emission scanning electron microscopy, respectively. The corrosion resistance of the samples was evaluated by potentiodynamic polarisation (Tafel). By comparing the corrosion behaviours of different structures, we found that the corrosion resistance of multilayered structure nickel coating was much higher than that of single layered nickel and the surface quality was significantly improved compared with dark nickel, which can better protect the NdFeB material.
SongZ-LLiW. Protection technology of NdFeB magnet materials: characteristics, applications and problems. J Magn Mater Devices. 2008; 39 (01): 1–6.
2.
RenC-DJinW-YZhouH-B. Key preparation techniques for sintered Nd-Fe-B magnets of high-performance. Chinese J Rare Metals. 2008; 37 (02): 249–254.
3.
JiangL-QXiaQ-PZhengJ. Corrosion and protection of sintered Nd-Fe-B magnets. Mater Protect. 2007; 40 (12): 48–52. +97.
4.
ZhangTChenFugangZhengYan. Hot-deformed Nd-Fe-B magnets fabricated by dynamic loading with a high maximum energy product. Intermetallics. 2016; 73: 67–71. doi: 10.1016/j.intermet.2016.04.001
5.
MaBSunAizhiLuZhenwen. Effects of surface modification of Nd-Fe-B powders using parylene C by CVDP method on the properties of anisotropic bonded Nd–Fe–B magnets. J Magn Magn Mater. 2016; 416: 150–154. doi: 10.1016/j.jmmm.2016.05.013
6.
PopovAGGavikoVSShchegolevaNN. Effect of addition of esters of fatty acids on the microstructure and properties of sintered Nd–Fe–B magnets produced by PLP. J Magn Magn Mater. 2015; 386: 134–140. doi: 10.1016/j.jmmm.2015.03.069
7.
ZhangS-MZhouY-Q. Corrosion prevention of NdFeB magnet. Mater Protect. 1999; 32 (09): 28–30.
8.
ZhangJ-XZhangT-JCuiK. Mechanism and prevention of NdFeB magnet corrosion. Dev Appl Mater. 2001; 16 (4): 38–41.
9.
YangH. Protection of NdFeB magnets by corrosion resistance phytic acid conversion film. Appl Surf Sci. 2015; 355: 1215–1221. doi: 10.1016/j.apsusc.2015.07.053
10.
CaoXChenLingGuoShuai. Impact of TbF3 diffusion on coercivity and microstructure in sintered Nd–Fe–B magnets by electrophoretic deposition. Scr Mater. 2016; 116: 40–43. doi: 10.1016/j.scriptamat.2016.01.034
11.
SadullahoğluGAltuncevahirBAddemirO. Effect of Al and Cu additions on microstructure and magnetic properties of NdTb-FeCo-B magnets. Acta Phys Pol A. 2014; 125: 1172–1175. doi: 10.12693/APhysPolA.125.1172
12.
NiJZhouSJiaZ. Improvement of corrosion resistance in Nd–Fe–B sintered magnets by intergranular additions of Sn. J Alloy Compd. 2014; 588: 558–561. doi: 10.1016/j.jallcom.2013.11.006
AlperMKockarHSafakM. Comparison of Ni–Cu alloy films electrodeposited at low and high pH levels. J Alloy Compd. 2008; 453: 15–19. doi: 10.1016/j.jallcom.2006.11.066
15.
PellicerEVareaAPanéS. Nanocrystalline electroplated Cu–Ni: metallic thin films with enhanced mechanical properties and tunable magnetic behavior. Adv Funct Mater. 2010; 20: 983–991. doi: 10.1002/adfm.200901732
16.
ZhangLJingC. New technics of NdFeB surface treatment. Electronics Process Tech. 2009; 30 (04): 230–232.
RampinIBisagliaFDabalàM. Corrosion properties of NdFeB magnets coated by a Ni/Cu/Ni layer in chloride and sulfide environments. J Mater Eng Perform. 2010; 19: 970–975. doi: 10.1007/s11665-009-9568-6
19.
TorabinejadVAliofkhazraeiMSabour RouhaghdamA. Tribological properties of Ni-Fe-Co multilayer coatings fabricated by pulse electrodeposition. Tribol Int. 2017; 106: 34–40. doi: 10.1016/j.triboint.2016.10.025
20.
EtminanfarMrHeydarzadeh SohiM. Corrosion resistance of multilayer coatings of nanolayered Cr/Ni electrodeposited from Cr(III)–Ni(II) bath. Thin Solid Films. 2012; 520: 5322–5327. doi: 10.1016/j.tsf.2012.03.127
21.
ZhangHLiuLBaiJ. Corrosion behavior and microstructure of electrodeposited nano-layered Ni–Cr coatings. Thin Solid Films. 2015; 595: 36–40. doi: 10.1016/j.tsf.2015.10.046
22.
YogeshaSChitharanjan HegdeA. Optimization of deposition conditions for development of high corrosion resistant Zn–Fe multilayer coatings. J Mater Process Technol. 2011; 211: 1409–1415. doi: 10.1016/j.jmatprotec.2011.03.010
23.
LiuWHouJ. Production status and prospect of NdFeB magnet electroplating. Plating Finish. 2012; 34 (04): 20–25.
24.
LiJZhouYChengX-H. Comparison of anticorrosion properties of nickel coating on sintered Nd-Fe-B[J]. Chinese Rare Earths. 2011; 32 (03): 19–23.
25.
ChenX-PWangX-DJiangD-M. Micro/nano-structure and mechanism of anti-sticky thin film on copper substrate. Mater Protect. 2005; 38 (07): 14–17+69-70.
