Corrosion behavior of electrodeposited Ni-Co alloy coatings under the presence of NaCl deposit at 800 °C

It is studied with XRD, SEM/EDX and thermogravimetric analysis under NaCl deposit at 800 °C in air for the corrosion behavior of electrodeposit Ni-Co alloy coatings prepared by direct current, single pulse current and double pulse current, respectively. The result shows that accelerated corrosion is observed on the three types of coatings under NaCl deposit and loose corrosion product layer with worse adhesion to matrix forms. Relatively, the resistance to corrosion for Ni-Co alloy coatings prepared by double pulse current is the highest, and that by direct current is the worst, which is attributed to the denser crystal coating for the samples prepared by double pulse current. The corrosion mechanism and the reasons for NaCl accelerated the corrosion of Ni-Co alloy coatings are discussed under the environment.