Erosion-Corrosion Behavior of Electroless Ni-P Coating on Copper-Nickel Alloy in 3.5 wt.% Sodium Chloride Solution
Abstract
The present investigation concerns electroless Ni-P coatings prepared onto the copper-nickel alloy (CuNi 90/10) to enhance the erosion-corrosion resistance. X-ray diffraction technique (XRD), scanning electron microscopy, and electrochemical methods were utilized to study the heat treatment effects on the erosion-corrosion resistance and the physical properties of the coatings. The results indicated that both the as-plated and coating with post-heat treatment (PHT) showed much higher self-passivation ability and much lower current densities than that of the copper-nickel alloy (CuNi 90/10). XRD results showed that both the as-plated and coating with PHT had amorphous structure and the effect of PHT at 190 °C on the structure of Ni-P coating was not significant. Compared with coating with PHT, the as-plated exhibited lower erosion-corrosion resistance due to some small pits and cracks. The coating with PHT demonstrated significant improvement of erosion-corrosion resistance in 3.5 wt.% NaCl solution, which was attributed to better protective film, lower porosity of coatings, and high micro-hardness compared with Ni-P coating without PHT.
- Publication:
-
Journal of Materials Engineering and Performance
- Pub Date:
- January 2014
- DOI:
- 10.1007/s11665-013-0763-0
- Bibcode:
- 2014JMEP...23..230J
- Keywords:
-
- copper-nickel alloy;
- electroless;
- erosion-corrosion resistance;
- heat treatment;
- passivity;
- plating