Surface morphology and corrosion resistance of electrodeposited composite coatings containing polyethylene or polythiophene in Ni-Mo base

Abstract

Ni-Mo + PE_Ni and Ni-Mo + PTh composite coatings have been prepared by nickel-molybdenum deposition from a bath containing a suspension of PE_Ni or Th. These coatings were obtained at galvanostatic conditions, at a current density of j _dep = − 0.100 A cm⁻² and temperature of 293 K. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS. Electrochemical corrosion resistance investigations were carried out in 5 M KOH, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found, that the composite coatings containing thiophene are more corrosion resistant in alkaline solution than the Ni-Mo + PE_Ni coatings. This is caused by presence of the polymer on the coatings surface and decrease of corrosion active surface area of the coatings.