Study on the Growth and Corrosion Resistance of Manganese Phosphate Coatings on 25Cr2Ni4WA Alloy Steel

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Abstract:

The growth process and corrosion resistance of the phosphate coating on 25Cr2Ni4WA alloy steel fabricated by a high temperature manganese phosphating were investigated by XRD, SEM, EDS and electrochemical polarization method, respectively. It is found that the phosphate coating consists of lots of close packed lump crystallites and mainly composed of (Mn,Fe)5H2(PO4)4·4H2O. The coating weight increased rapidly, and then the increase rate slowed down when phosphating process was carried for about 5 min. The corrosion potentials of the phosphated steel shifted positively about 250 mV than the bare steel, indicating that the phosphating can improve the corrosion resistance of the 25Cr2Ni4WA alloy steel.

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Solid State Phenomena (Volume 185)

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73-76

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February 2012

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© 2012 Trans Tech Publications Ltd. All Rights Reserved

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