• Maksimovic, Miodrag
• Tomic, Milorad
• Pavlovic, Miomir
• Bajat, Jelena B.

Abstract

<jats:p>The electrochemical deposition by pulse current of Zn-Co alloy coatings onsteel was examined, with the aim to find out whether pulse plating couldproduce alloys that could offer a better corrosion protection. The influenceof on-time and the average current density on the cathodic currentefficiency, coating morphology, surface roughness and corrosion stability in3% NaCl was examined. At the same Ton/Toff ratio the current efficiency wasinsignificantly smaller for deposition at higher average current density. Itwas shown that, depending on the on-time, pulse plating could produce morehomogenous alloy coatings with finer morphology, as compared to depositsobtained by direct current. The surface roughness was the greatest for Zn-Coalloy coatings deposited with direct current, as compared with alloy coatingsdeposited with pulse current, for both examined average current densities. Itwas also shown that Zn-Co alloy coatings deposited by pulse current couldincrease the corrosion stability of Zn-Co alloy coatings on steel. Namely,alloy coatings deposited with pulse current showed higher corrosionstability, as compared with alloy coatings deposited with direct current, foralmost all examined cathodic times, Ton. Alloy coatings deposited at higheraverage current density showed greater corrosion stability as compared withcoatings deposited by pulse current at smaller average current density. Itwas shown that deposits obtained with pulse current and cathodic time of 10ms had the poorest corrosion stability, for both investigated averagedeposition current density. Among all investigated alloy coatings the highestcorrosion stability was obtained for Zn-Co alloy coatings deposited withpulsed current at higher average current density (jav = 4 A dm-2).</jats:p>

Topics

• Deposition
• density
• morphology
• surface
• corrosion
• steel
• current density