The Correlation of Texture and Microstructure to the Corrosion Resistance of Tin Coatings

Abstract

The influence of current density and temperature on the macrotexture, the orientation and size of grains, and the corrosion resistance of tin deposits was studied. Tin coatings with two different textures, (100) and (301) fiber textures were produced by electrodeposition at 20°C by varying current density. At a lower current density of 100A/m2, (301) fibre was obtained. At the current densities of 100 and up to 400 A/m2, only (100) fibre texture was observed. An increase in current density leads to a decrease in grain size. At the same current density, the grain size of tin coatings increases with increased temperature. The influence of temperature (20, 40, 60 and 80 °C) on texture is relatively negligible. The corrosion resistance of tin coatings increases with a decrease in grain size. The corrosion resistance of tin coating with (301) fibre is higher than that of tin coating with (100) fibre texture. The results suggest that texture and microstructure play an important role in controlling corrosion rate of tin based coatings.