Improving surface characteristic and corrosion inhibition of coating on Mg alloy by trace stannous (II) chloride

• Published in: Corrosion science Vol. 123; pp. 147 - 157
• Main Authors: Gan, Rong, Wang, Dongmei, Xie, Zhi-Hui, He, Ling
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 15.07.2017; Elsevier BV
• Subjects: A. Alloy; A. Metal coatings; Alloys; Atomic force microscopy; B. AFM; B. EIS; B. XPS; C. Neutral inhibition; Chloride resistance; Corrosion inhibitors; Corrosion prevention; Corrosion resistance; Corrosion resistant alloys; Deposits; Electrochemical impedance spectroscopy; Magnesium base alloys; Nickel coatings; Photoelectron spectroscopy; Protective coatings; Scanning electron microscopy; Spectroscopic analysis; Spectrum analysis; Studies; Surface properties; B. XPS; A. Metal coatings; B. AFM; A. Alloy; B. EIS; C. Neutral inhibition
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2017.04.018

•An effective additive is demonstrated for preparing Ni coating on Mg alloy.•Trace stannous chloride (SnCl2) is helpful to obtain smoother coating surface.•Trace SnCl2 is powerful in enhancing coating corrosion resistance.•The coating is Sn-free but properties improved. Duplex Ni coatings consisting of Ni–P deposits as primer layer and Ni–Sn–P deposits as outer layer were prepared on Mg alloy. These coatings exhibit uniform surface and improved corrosion resistance after adding trace stannous (II) chloride (SnCl2) into the outer layer plating bath. X-ray photoelectron spectroscopy proved the non-existence of Sn in the coating. The coating surface was characterized by scanning electron microscopy and atomic force microscopy. X-ray diffractometer patterns show that SnCl2 is favourable for amorphisation of the coating. The corrosion protection of the coating was confirmed by potentiodynamic polarisation and electrochemical impedance spectroscopy measurement.