The Synthesizion Of Nickel-chrome Nanocomposite Coatings And Investigation Of The Corrosion Behavior

Ni-Cr nanocomposite coating which can resist corrosion has a great application prospect.The amount of nano particles in deposits is one of the key factor that determines corrosion resistance of the nanocomposite coatings. How to increase the Cr content in composite coatings has become a current research focus. The Ni-Cr nanocomposite coatings were prepared by using dispersant, conventional electroplating(CEP), sediment co-deposition(SED).The properties of the resulting composite were investigated. The following are the salient conclusions of the present study:Anionic surfactants, cationic surfactant, natural polymer surfactant have been used in the pretreatment of Cr nano-particles. The investigation into the variation of Zeta potential, the deposition rules and the variation of the nano-particle contents in the deposit coatings depicted that the nano particles modified by the arabic gum can suspend the longest time during the deposition experiment and enjoy the highest nano Cr particle contents in the coatings, indicating that the modification of arabic gum is an important factor to increase the zeta potential of nano particles in water and to improve the suspension stability accordingly.When the Cr content in bath solution is low, the Cr content is much higher in the Ni-Cr nanocomposite coatings prepared by SCD technique than that in the coating by CEP technique. The processing parameters affecting the Cr contents in composite coatings were investigated and the optimum processing parameters were chosen: Cr concentration in plating solution 20g/l; current density 3A/dm~2; stirring rate 170rpm; solution pH 5.5. The SCD coating is more compact, smoother and more corrosion resistant than the CEP coating with the same Cr content.The effect of Cr particle size and content on the morphology and corrosion resistance of the composite coatings were depicted by SEM and a series of electrochemical measurements.The result show that the smaller Cr particle size and the higher content of Cr particles in the Ni-Cr nanocomposite coatings led to a compact and smooth surface with good corrosion resistance.