Effect of Crystal Orientation on the Anodic Polarization and Passivity of Zinc

Potentiostatic polarization measurements on exposed (0001), (101¯0), and (112¯0) faces of single crystals and on polycrystalline zinc were made in aqueous solutions of sodium hydroxide. Crystal orientation was observed to have a well defined effect on anodic polarization with overvoltages for active dissolution increasing with increasing density of crystal planar packing. Potentials for passivation were equal for (0001) and (101¯0) crystal specimens, which were both noble to potentials for (112¯0) specimens.