Original Article | 2007, Vol.29, No.4, pp. 1029-1038
Sealing of thermally-sprayed stainless steel coatings against corrosion using nickel electroplating technique
Hathaipat Koiprasert and Panadda Niranatlumpong
pp. 1029 - 1038
Abstract
Electric arc spraying (EAS) is one of the thermal spray techniques used for restoration and to provide corrosion resistance. It can be utilized to build up coatings to thicknesses of several millimeters, It is easy to use on-site. Most importantly, the cost of this technique is lower than other thermal spraying techniques that may be suitable for part restoration. A major disadvantage associated with the electric arc sprayed coating is its high porosity, which can be as high as 3-8% making it not appropriate for use in immersion condition. This work was carried out around the idea of using electroplating to seal off the pore of the EAS coating, with an aim to improve the corrosion resistance of the coating in immersion condition. This research compared the corrosion behavior of a stainless steel 316 electric arc sprayed coating in 2M NaOH solution at 25°C. It was found that the Ni plating used as sealant can improve the corrosion resistance of the EAS coating. Furthermore, the smoothened and plated stainless steel 316 coating has a better corrosion resistance than the plated EAS coating that was not ground to smoothen the surface before plating.
