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Characteristics and corrosion behavior of nickel‐phosphorus coatings deposited by a simplified bath
Author(s) -
Guo S. Q.,
Hou L. F.,
Guo C. L.,
Wei Y. H.
Publication year - 2017
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.201609155
Subject(s) - materials science , coating , dielectric spectroscopy , scanning electron microscope , gravimetric analysis , microstructure , polyvinylpyrrolidone , corrosion , amorphous solid , metallurgy , chemical engineering , alloy , electrochemistry , nickel , deposition (geology) , composite material , chemistry , polymer chemistry , paleontology , organic chemistry , electrode , sediment , engineering , biology
An economical formulation is introduced for electroless Ni‐P coating on AZ31B Mg alloy, and the multifunctional additive polyvinylpyrrolidone as the only additive is used for the electroless bath. The effect of PVP concentration on electroless Ni‐P coating is researched in detail. The total deposition rate of the Ni‐P coating is estimated by the gravimetric method. It is shown that with the increases of PVP concentration in electroless solution, the total deposition rate for Ni‐P coatings decreases. The microstructure and surface morphologies of Ni‐P coatings are characterized by X‐ray diffraction and scanning electron microscopy. Moreover, electrochemical impedance spectroscopy and polarization measurement are used to evaluate the anticorrosion property of the Ni‐P coatings in 3.5% NaCl solution. The results show that a mixture of crystalline and amorphous Ni‐P coating with medium phosphorus content is successfully deposited on the AZ31B Mg alloy. Furthermore, the Ni‐P coating displays preferable properties in both micro‐hardness and corrosion resistance when the concentration of PVP is 10 g/L.