| LU Jie-qin,ZHANG Xiao-li,WEI Guo-ying,YU Yun-dan.Preparation and Corrosion Resistance of Electroless Plating Ni-W-P Alloy[J],45(4):83-88,104 |
| Preparation and Corrosion Resistance of Electroless Plating Ni-W-P Alloy |
| Received:November 13, 2015 Revised:April 20, 2016 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2016.04.014 |
| KeyWord:copper-zinc alloy substrates electroless Ni-W-P alloy surface morphology anti-corrosion polarization curve |
| Author | Institution |
| LU Jie-qin |
College of Material Science & Engineering,China Jiliang University, Hangzhou , China |
| ZHANG Xiao-li |
College of Material Science & Engineering,China Jiliang University, Hangzhou , China |
| WEI Guo-ying |
College of Material Science & Engineering,China Jiliang University, Hangzhou , China |
| YU Yun-dan |
College of Material Science & Engineering,China Jiliang University, Hangzhou , China |
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| Abstract: |
| Objective Ni-W-P coatings were prepared on copper-zinc alloy substrates by electroless deposition to study the anticorrosion performance. Methods Ni-W-P coatings were prepared by electroless deposition using hypophosphite as reducing agent and sodium citrate as complexing agent in the alkaline solution (pH = 11). The investigation was focused on the effects of chemical agents and reaction time on the performance of Ni-W-P coatings. The thickness, surface morphology and corrosion behavior of the coatings were analyzed by X-ray fluorescence analyzer, scanning electron microscopy (SEM) and electrochemical workstation, respectively. Results With the increasing concentrations of reducing agent (0. 1 ~ 0. 4 mol / L) and complexing agent (0. 18 ~ 0. 28 mol / L), the thickness of the coatings reached the maximum. Especially, Ni-W-P coatings with thickness of 0. 2975 μm and 0. 1978 μm could be obtained respectively in the conditions of 0. 2 mol / L reducing agent and 0. 26 mol / L complexing agent. With the increasing concentration of reducing agent, the surface density increased while the porosity decreased. When the concentration of hypophosphite was 0. 1 mol / L, coatings with smaller particles and porous surface could be obtained. However, dense and uniform coatings could be detected at the condition of 0. 4 mol / L hypophosphite. Corrosion current density reached the minimum when the reducing agent concentration was 0. 4 mol / L, and the complexing agent concentration was 0. 28 mol / L, which corresponded to 2. 38×10 -6 A / cm2 and 2. 23×10 -6 A / cm2 , respectively. With the increasing concentrations of reducing agent and complexing agent, more compact coatings could be prepared. Moreover, along with the increasing reaction time, coating thickness changed significantly and the corrosion current density decreased. The corrosion current density reached the minimum and Ni-W-P with a thickness of 4. 14 μm could be prepared when the reaction time was 4 hours. Conclusion The coatings with the best corrosion resistance were obtained with 0. 4 mol / L of reducing agent and 0. 28 mol / L of complexing agent. In addition, longer reaction time helped to optimize the corrosion resistance of the coatings. |
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