Microstructure and Corrosion Resistance of Ni-Co/SiC Nanocomposite Coating for Marine Machinery

作者：Li Baosong^*; Zhang Wen; Huan Yuxing; Zhang Weiwei

来源：Rare Metal Materials and Engineering, 2018, 47(5): 1509-1516.

• electrodeposition
• SiC
• Ni-Co/SiC alloys
• corrosion resistance
• nano composite coatings

The effects of SiC nanoparticles on the structure and morphology of Ni-Co coating were investigated by scanning electron microscopy (SEM), energy spectrum analysis (EDS) and X-ray diffraction (XRD). The influences of SiC nanoparticles on Ni-Co composite electrodeposition process and the electrochemical corrosion properties of Ni-Co/SiC composite coatings were studied by EIS and Tafel methods. The results show that the addition of Co2+ ions refines the grains of the Ni coating, reduces the porosity, transforms some structure to amorphous and improves the corrosion resistance. SiC nanoparticles can promote the nucleation and growth of Ni-Co alloy and improve the hardness of the alloys. Compared with Ni-Co alloys, Ni-Co/SiC coatings have excellent corrosion and wear resistance, which have more positive E-corr, lower i(cor), and larger R-c. The Ni-Co/SiC composite coatings have the better stability of service performance, while the corrosion resistance of Ni-Co alloy decreases fast in 3.5 wt% NaCl solution. The process of corrosion experiences three stages, namely a wetting stage, a diffusion control stage in which electrolyte transports in the coating and an electrochemical control stage in which diffusion rate is larger than the electrochemical rate after electrolytes reach the substrate surface. Ni-Co/SiC alloys can provide long-term protection of marine engineering machinery under the influence of multifactors interaction in seawater environment.

• 出版日期2018-5
• 单位河海大学