Electrochemical Characteristics of an Optimized Ni-P-Zn Electroless Composite Coating

An optimized electroless solution was used to deposit the Ni-P-Zn composite coating. Potentiodynamic polarization test, salt spray technique and electrochemical impedance spectroscopy were utilized to study electrochemical characteristics of the as-deposited coating. All results demonstrate an excellent corrosion resistance of the as-deposited layer. Corrosion current density of the coating was compared to some similar coatings reported in other papers to study reasons of its high corrosion resistance. It was proved that the high corrosion protection of the coating is due to the optimization of P and Zn contents in the coating composition.