Control of Texture and Microstruture of Electrogalvanized Zn in Acid Sulfate Solution
임영복Young Bok Yim, 황선근Sun Keun Hwang
Abstract
Crystallographic texture and microstructure characteristics of electrogalvanized zinc on carbon steel in zinc sulfate solution was studied in terms of chloride concentration in the electrolyte and the current density. The chloride addition strengthened the basal texture of the electroplated layer by increasing the conductivity of electrolyte and lowering the cathod overvoltage. On the other hand, increasing the current density weakened the basal texture by increasing the cathode overvoltage. Chloride addition also promoted a ridge type surface topographical feature parallel to the substrate surface, and a granular cross-sectional grain size decreased with the chloride content. Increasing the current density resulted in a ridge type structure inclined to the substrate surface and a columnar cross-sectional microstructure. Increased current density also reduced the cross-sectional grain size due to accelerated nucleation rate. Hardness of the electrogalvanized layer increased with the reduced grain size or adsorbed chloride.