Abstract
A protective Al coating was achieved on the sintered NdFeB magnet by cold spray. The sprayed Al particles generate plastic deformation and hang together. The thickness of the coating is about 170 μm. The corrosion currents of Al coating and NdFeB without immersion tested by potentiodynamic polarization in 3.5 wt.% NaCl solutions are 1.350 × 10−6 and 4.361 × 10−6 A/cm2, respectively. X-ray photoelectron spectrometry results confirm that the oxide film is Al2O3 and the corrosion process can be derived into two different stages. The Al coating can provide long-term protection for NdFeB effectively.
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M. Sagawa, S. Fujimura, N. Togawa, H. Yamamoto, and Y. Matsuura, New Material for Permanent Magnets on a Base of Nd and Fe, J. Appl. Phys., 1984, 55, p 2083-2087
Y.W. Song, H. Zhang, H.X. Yang, and Z.L. Song, A Comparative Study on the Corrosion Behavior of NdFeB Magnets in Different Electrolyte Solutions, Mater. Corros., 2008, 59, p 794-801
M. Rada, A. Gebert, I. Mazilu, K. Khlopkov, O. Gutfleisch, L. Schultz, and W. Rodewald, Corrosion Studies on Highly Textured Nd-Fe-B Sintered Magnets, J. Alloys Compd., 2006, 415, p 111-120
H. Bala, G. Pawlowska, S. Azymura, V.V. Sergeev, and Y.M. Rabinovich, Corrosion Characteristics of NdFeB Sintered Magnets Containing Various Alloying Elements, J. Magn. Magn. Mater., 1990, 87, p L225-L259
S. Sunada, K. Majima, Y. Akasofu, and Y. Kaneko, Corrosion Assessment of Nd-Fe-B Alloy with Co Addition Through Impedance Measurements, J. Alloy Compd., 2006, 408-412, p 1373-1376
P. Mitchell, Corrosion Protection of NdFeB Magnets, IEEE Trans. Magn., 1990, 26, p 1933-1935
Z. Chen, A. Ng, J.Z. Yi, and X.F. Chen, Multi-Layered Electroless Ni-P Coatings on Powder-Sintered Nd-Fe-B Permanent Magnet, J. Magn. Magn. Mater., 2006, 302, p 216-222
T. Minowa, M. Yoshikawa, and M. Honshima, Improvement of the Corrosion Resistance on Nd-Fe-B Magnet with Nickel Plating, IEEE Trans. Magn., 1989, 25, p 3776-3778
A.S. Kim and F.E. Camp, A High Performance Nd-Fe-B Magnet with Improved Corrosion Resistance, IEEE Trans. Magn., 1992, 28, p 2151-2153
W. Fernenge, W. Rodewald, R. Blank, P. Schrey, M. Katter, and B. Wall, The Influence of Co on the Corrosion Resistance of Sintered Nd-Fe-B Magnets, J. Magn. Magn. Mater., 1999, 196, p 288-290
L.Q. Yu, Y.H. Wen, and M. Yan, Effects of Dy and Nb on the Magnetic Properties and Corrosion Resistance of Sintered NdFeB, J. Magn. Magn. Mater., 2004, 283, p 353-356
X.K. Yang, Q. Li, S.Y. Zhang, X.K. Zhong, Y. Dai, and F. Guo, Electrochemical Corrosion Behaviors and Protective Properties of Ni-Co-TiO2 Composite Coating Prepared on Sintered NdFeB Magnet, Mater. Corros., 2010, 61, p 618-625
H.Z. Rao, G.H. Li, and P.L. Wang, Protective Coating for NdFeB Permanent Magnet Materials, Chin. Rare Earths, 1999, 20, p 40-43
K.O. Legg, M. Graham, P. Chang, F. Rastagar, A. Gonzales, and B. Sartwell, The Replacement of Electroplating, Surf. Coat. Technol., 1996, 81, p 99-105
J.K. Chang, S.Y. Chen, W.T. Tsai, M.J. Deng, and I.W. Sun, Electrodeposition of Aluminum on Magnesium Alloy in Aluminum Chloride (AlCl3)-1-ethyl-3-methylimidazolium Chloride (EMIC) Ionic Liquid and Its Corrosion Behavior, Electrochem. Commun., 2007, 9, p 1602-1606
N.C. Ku, C.D. Qin, C.C. Yu, and D.H.L. Ng, Corrosion Resistance of NdFeB Magnets Coated by Al, IEEE Trans. Magn., 1996, 32, p 4407-4409
D.P. Monaghan, D.G. Teer, P.A. Logan, K.C. Laing, R.I. Bates, and R.D. Arnell, An Improved Method for the Deposition of Corrosion-resistant Aluminium Coatings for Aerospace Applications, Surf. Coat. Technol. 1993, 60, p 592-596
A.P. Alkhimov, V.F. Kosarev, and A.N. Papyrin, Gas-Dynamic Spraying: An Experimental Study of the Spraying Process, J. Appl. Mech. Tech. Phys., 1998, 39, p 318-323
V.K. Champagne, D.J. Helfritch, and P.F. Leyman, Magnesium Repair by Cold Spray, Plat. Surf. Finish., 2008, 95, p 19-28
Y.S. Tao, T.Y. Xiong, C. Sun, H. Jin, H. Du, and T.F. Li, Effect of α-Al2O3 on the Properties of Cold Sprayed Al/α-Al2O3 Composite Coatings on AZ91D Magnesium Alloy, Appl. Surf. Sci., 2009, 256, p 261-266
S.Z. Mao, H.X. Yang, J.L. Li, H.G. Ying, and Z.L. Song, The Properties of Aluminium Coating on Sintered NdFeB by DC Magnetron Sputtering, Vacuum, 2011, 85, p 772-775
S.D. Mao, H.X. Yang, Z.L. Song, J.L. Li, H.G. Ying, and K.F. Sun, Corrosion Behavior of Sintered NdFeB Deposited with an Aluminium Coating, Corros. Sci., 2011, 53, p 1887-1894
S.Z. Song and Z.L. Tang, An Electrochemical Impedance Analysis on Aluminum in 3.5% NaCl Solution, J. Chin. Soc. Corros. Prot., 1996, 16, p 127-132
S.D. Mao, H.X. Yang, J.L. Li, F. Huang, and Z.L. Song, Corrosion Properties of Aluminium Coatings Deposited on Sintered NdFeB by Ion-Beam-Assisted Deposition, Appl. Surf. Sci., 2011, 57, p 5581-5585
M. Yue, J.X. Zhang, W.Q. Liu, and G.P. Wang, Corrosion Kinetics of Spark Plasma Sintering Nd-Fe-B Magnets in Different Electrolytes, IEEE Tran. Magn., 2005, 41, p 3892-3894
Y.S. Huang, X.T. Zeng, X.F. Hu, and F.M. Liu, Corrosion Resistance Properties of Electroless Nickel Composite Coatings, Electrochim. Acta, 2004, 49, p 4313-4319
E. Barsoulkov, and J.R. Macdonald, Impedance Spectroscopy Theory, Experiment, and Application, 2nd ed., Wiley, Hoboken, NJ, 2005.
J.B. Bessone, D.R. Salinas, C.E. Mayer, M. Ebert, and W.J. Lorenz, An EIS Study of Aluminium Barrier-Type Oxide Films Formed in Different Media, Electrochim. Acta, 1992, 37, p 2283-2290
J.F. Zhang, W. Zhang, C.W. Yan, K.Q. Du, and F.H. Wang, Corrosion Behaviors of Zn-Al-Mn Alloy Composite Coatings Deposited on Magnesium Alloy AZ31B (Mg-Al-Zn), Electrochim. Acta, 2009, 55, p 560-571
H. Zhang, Y.L. Zhao, and Z.D. Jiang, Effects of Temperature on the Corrosion Behavior of 13Cr Martensitic Stainless Steel During Exposure to CO2 and Cl− Environment, Mater. Lett., 2005, 59, p 3370-3374
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This work was supported by a grant from the National High Technology Research and Development Program of China under the contract of 2012BAE02B01.
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Ma, C., Liu, X. & Zhou, C. Cold-Sprayed Al Coating for Corrosion Protection of Sintered NdFeB. J Therm Spray Tech 23, 456–462 (2014). https://doi.org/10.1007/s11666-013-9994-8
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DOI: https://doi.org/10.1007/s11666-013-9994-8