Top

Rare Metals

Published in:

21-06-2015

Corrosion prevention of sintered Nd–Fe–B magnet by a phosphate chemical conversion treatment

Authors: Xia Ding, Xiu-Chun Wang, Kai-Hong Ding, Sheng-Li Cui, Yong-Cong Sun, Mu-Sen Li

Published in: Rare Metals | Issue 1/2021

Activate our intelligent search to find suitable subject content or patents.

search-config

AI-assisted search

Off

Abstract

The corrosion-resistant coating formed on the surface of sintered Nd–Fe–B magnet by a phosphate chemical conversion (PCC) treatment was studied. The morphology, phase composition and thickness of the coating were investigated by field emission scanning electron microscopy (FE-SEM), energy-dispersive spectrometer (EDS), Fourier transform infrared (FTIR) spectrometer and coating thickness gauge. The corrosion behaviour of the phosphated magnet was evaluated by copper sulphate spot test, neutral salt spray test and electrochemical potentiodynamic polarization experiment. The magnetic properties of the phosphated magnet were also tested. The experimental results show that the phosphate coating has such characteristics as dense granular growth, uniform distribution and thickness range of 10–18 μm. The corrosion resistance of the magnet is significantly improved by phosphate coating without losing magnetic properties. Therefore, this highly efficient PCC was a good way for increasing the corrosion resistance of the sintered Nd–Fe–B magnets.

previous article Origin of low coercivity of high La–Ce-containing Nd–Fe–B sintered magnets

next article Mechanical properties and microstructure of in situ formed Ti2AlN/TiAl(WMS) composites

Dont have a licence yet? Then find out more about our products and how to get one now:

Springer Professional "Wirtschaft+Technik"

Online-Abonnement

Mit Springer Professional "Wirtschaft+Technik" erhalten Sie Zugriff auf:

über 102.000 Bücher
über 537 Zeitschriften

aus folgenden Fachgebieten:

Automobil + Motoren
Bauwesen + Immobilien
Business IT + Informatik
Elektrotechnik + Elektronik
Energie + Nachhaltigkeit
Finance + Banking
Management + Führung
Marketing + Vertrieb
Maschinenbau + Werkstoffe
Versicherung + Risiko

Jetzt Wissensvorsprung sichern!

inform now

Springer Professional "Technik"

Online-Abonnement

Mit Springer Professional "Technik" erhalten Sie Zugriff auf:

über 67.000 Bücher
über 390 Zeitschriften

aus folgenden Fachgebieten:

Automobil + Motoren
Bauwesen + Immobilien
Business IT + Informatik
Elektrotechnik + Elektronik
Energie + Nachhaltigkeit
Maschinenbau + Werkstoffe

Jetzt Wissensvorsprung sichern!

inform now

[1]

Sagawa M, Hirosawa S, Yamamoto H, Fujimura S, Matsuura Y. Nd–Fe–B permanent magnet materials. Jpn J Appl Phys. 1987;26(6):785.CrossRef

[2]

Schultz L, El-Aziz AM, Barkleit G, Mummert K. Corrosion behaviour of Nd–Fe–B permanent magnetic alloys. Mater Sci Eng A. 1999;267(2):307.CrossRef

[3]

Jiang CB, An SZ. Recent progress in high temperature permanent magnetic materials. Rare Met. 2013;32(5):431.CrossRef

[4]

Wu Q, Zhang PY, Pan MX, Li DY, Ge HL. Crystallization kinetics and magnetization behavior of RE_3.5Fe_66.5Co₁₀B₂₀ (RE = Pr, Nd) nanocomposite ribbons. Rare Met. 2014;33(6):681.CrossRef

[5]

Man HH, Man HC, Leung LK. Corrosion protection of NdFeB magnets by surface coatings—Part 2: electrochemical behaviour in various solutions. J Magn Magn Mater. 1996;152(1):47.CrossRef

[6]

Li WF, Ohkubo T, Hono K. Effect of post-sinter annealing on the coercivity and microstructure of Nd–Fe–B permanent magnets. Acta Mater. 2009;57(5):1337.CrossRef

[7]

Tsubokawa Y, Shimizu R, Hirosawa S, Sagawa M. Effect of heat treatment on grain-boundary microstructure in Nd–Fe–B sintered magnet. J Appl Phys. 1988;63(8):3319.CrossRef

[8]

Minowa T, Yoshikawa M, Honshima M. Improvement of the corrosion resistance on Nd–Fe–B magnet with nickel plating. IEEE Trans Magn. 1989;25(5):3776.CrossRef

[9]

Rieger G, Seeger M, Sun Li, Kronmuller H. Micromagnetic analysis applied to melt-spun NdFeB magnets with small additions of Ga and Mo. J Magn Magn Mater. 1995;151(1):193.CrossRef

[10]

Tokuhara K, Hirosawa S. Corrosion resistance of Nd–Fe–B sintered magnets. J Appl Phys. 1991;69(8):5521.CrossRef

[11]

Sagawa M, Tenaud P, Vial F, Hiraga K. High coercivity Nd–Fe–B sintered magnet containing vanadium with new microstructure. IEEE Trans Magn. 1990;26(5):1957.CrossRef

[12]

Hirosawa S, Mino S, Tomizawa H. Improved corrosion resistance and magnetic properties of Nd–Fe–B sintered magnets with Mo and Co. J Appl Phys. 1991;69(8):5844.CrossRef

[13]

Bala H, Pawlowska G, Szymura S, Rabinovich YM. Electrochemical corrosion characterisation of intermetallic phases occurring in Nd–Fe–B type magnets. Br Corros J. 1998;33(1):37.CrossRef

[14]

Pierri E, Tsamouras D, Dalas E. Ferric phosphate precipitation in aqueous media. J Cryst Growth. 2000;213(1):93.CrossRef

[15]

Costa I, Sayeg IJ, Faria RN. The corrosion protection of RE-iron-boron magnets by a phosphate treatment. IEEE Trans Magn. 1997;33(5):3907.CrossRef

[16]

Qin CD, Li ASK, Ng DHL. The protective coatings of NdFeB magnets by Al and Al (Fe). J Appl Phys. 1996;79(8):4854.CrossRef

[17]

Man HH, Man HC, Leung LK. Corrosion protection of NdFeB magnets by surface coatings—Part I: salt spray test. J Magn Magn Mater. 1996;152(1):40.CrossRef

[18]

Tamborim Takeuchi SM, Azambuja DS, Costa I. Cerium conversion layer for improving the corrosion resistance of phosphated NdFeB magnets. Surf Coat Tech. 2006;201(6):3670.

[19]

Hawthorne HM, Neville A, Troczynski T, Hu X, Thammachart M, Xie Y, Fu J, Yang Q. Characterization of chemically bonded composite sol–gel based alumina coatings on steel substrates. Surf Coat Tech. 2004;176(2):243.CrossRef

[20]

Fujioka E, Nishihara H, Aramaki K. The inhibition of passive film breakdown on iron in a borate buffer solution containing chloride ions by mixtures of hard and soft base inhibitors. Corros Sci. 1996;38(10):1915.CrossRef

Title: Corrosion prevention of sintered Nd–Fe–B magnet by a phosphate chemical conversion treatment
Authors: Xia Ding
Xiu-Chun Wang
Kai-Hong Ding
Sheng-Li Cui
Yong-Cong Sun
Mu-Sen Li
Publication date: 21-06-2015
Publisher: Nonferrous Metals Society of China
Published in: Rare Metals / Issue 1/2021
Print ISSN: 1001-0521
Electronic ISSN: 1867-7185
DOI: https://doi.org/10.1007/s12598-015-0533-2

Springer Professional

Abstract

Please log in to get access to your license.

Dont have a licence yet? Then find out more about our products and how to get one now:

Springer Professional "Wirtschaft+Technik"

Springer Professional "Technik"

Other articles of this Issue 1/2021

Origin of low coercivity of high La–Ce-containing Nd–Fe–B sintered magnets

Electrolytic properties and element migration in Ni–TiB2/Al2O3 composite cathode

Green, cheap and rechargeable Al–N2 battery with efficient N2 fixation

Realizing simultaneously enhanced energy and power density full-cell construction using mixed hard carbon/Li4Ti5O12 electrode

A comparative study of rhenium coatings prepared on graphite wafers by chemical vapor deposition and electrodeposition in molten salts

Aging resistance and mechanical properties of Sn3.0Ag0.5Cu solder bump joints with different bump shapes

Premium Partners