Properties of SiO₂/PTFE-Ni Composite Coatings Prepared by Jet Electrodepositon

Nickel-base composite coatings containing SiO2 and polytetrafluoroethylene (PTFE) were prepared by high-speed-jet electrodeposition on steel substrate.Surfactants were added in the electroplating solution for particle dispersion.Magnetic stirring was used to keep particles from sediment.The influences of PTFE and SiO2 contents and jet velocity on the microstructure and properties of the composite coatings were studied.The morphology and microstructure of the coatings were analyzed with scanning electron microscopy.The wear resistance tests were performed using a pin-on-disc tribometer.The corrosion rates of the coatings in the man-made seawater were investigated.It was showed that the surface morphology of the composite coatings were flatter than that of pure nickel coating,and became flatter and compacter with increase of jet speed and the contents of SiO2 or/and PTFE in the coatings.Compared with the value of wear rate of the nickel coatings,addition of PTFE or/and SiO2 in nickel coating significantly improved the characteristics of the anti-wearing of the coatings by more than 5 times.Ni-PTFE-SiO2 composite coatings demonstrated superior wear resistance to Ni-PTFE or Ni-SiO2 coatings under the same experimental conditions.Corrosion rates of the coatings decreased with the increase of the PTFE content in the coatings.