Anticorrosive and Hydrophobic Ni-Co Coatings Produced Using Simple Pulse Electrodeposition

Abstract

Ni-Co alloy coatings exhibit well-known properties, including mechanical, wear, and anticorrosive resistances, high magnetic performance, thermal stability at high temperatures, and good adhesion. However, these coatings exhibit hydrophilic characteristics, which hinder their applications under high-humidity conditions (e.g., in solar panels or anti-freeze systems). Many studies have focused on the production of hydrophobic Ni-Co coatings to enhance their performance in humid environments. In the present study, hydrophobic Ni-Co coatings were deposited on carbon steel from sodium tartrate baths in a one-pot process using simple pulsed current (SPC) electrodeposition. An anomalous deposition process was observed regardless of the duty cycle ( γ ) and frequency ( F ) used to produce these coatings. The morphology of the SPC-produced coatings changed from granular to needle-like grains as γ and F increased, leading to increased roughness ( R q ) and contact angle ( CA ), as well as enhanced charge transfer resistance ( R ct ). Based on the present results, F = 2000 Hz and γ = 50% were the most suitable conditions for producing improved hydrophobic and anticorrosive Ni-Co coatings, exhibiting R q  = 1.244 μm, CA = 109.72°, and R ct  = 3001 Ω cm 2 .