HYDROGEN PERMEATION DURING ZINC MANGANESE ALLOY-PLATING

Electrodeposition of metals from solution is usually accompanied by th e simultaneous discharge of hydrogen ions or water molecules. When hyd rogen is liberated at an iron/steel surface during electrodeposition, a portion of the hydrogen is absorbed by the metal surface and then di ffuses into the interior. The diffused hydrogen produces some detrimen tal effects, such as reduction in ductility and loss in mechanical str ength, leading to hydrogen embrittlement. The present paper reports in vestigations on hydrogen permeation measurements in zinc-manganese all oy deposition using a modified electrode clamp for easy removal and fi xing of the electrode. Hydrogen permeation studies indicate that the p orosity of the deposit increases in the following order: Zn-Mn(14.3%), Zn-Mn(2.4%), Zn-Mn(24.8%) and Zn-Mn(37.5%). This is in agreement with the corrosion data obtained which indicates that Zn-Mn alloy deposits with low manganese content show better performance than pure zinc dep osits.