Improvement the Corrosion Resistance of Cr / Ni Alloy ElectroplatingCoatings in 3.5% NaCl Solution With Chemical Activation of substrate

The overall objective of this study is selecting an optimal method for the production ofchromium/ nickel coatings to reduce the density and permeability of the surface cracksand provide good corrosion resistance. For this purpose, Cr and Ni electrodeposited fromCr(III) - Ni(II) bath on St-12 steel samples by using pulse current, according to theselective three methods. The microstructures of the coatings were studied by opticalmicroscopy (OM) and scanning electron microscopy (FESEM). The coating corrosionresistance has been compared through electrochemical polarization in a 3.5% NaClsolution. Despite the high corrosion resistance for all three types of coatings; It also looksat the use of pulse current: corrosion resistance of multilayer alloy coatings are higherthan double layer, and corrosion resistance of double layer alloy coatings are higher thanthe single layer At the same thickness

Keywords:

Electroplating , Chromium , Nickel , Corrosion , Crack