MORPHOLOGY AND MICROSTRUCTURE OF PULSED ELECTRODEPOSITED ZINC-IRON BINARY ALLOY

Zinc-iron electrodeposited sheet steels have been widely adopted for automobile bodies for their improvements in corrosion resistance and paintability. Deposits with various pulse off time have been electrodeposited from sulfate bath and examined by scanning microscopy and X-ray diffraction. All the deposits consist of the η- and Γ-phases. The deposit morphology consists of hexagonal columnar crystals and Γ-phases dispersively precipitated within the grain and grain boundary of the η-phase plates. For the 1.0 ms pulse off time deposit, of granular crystals form only on the (00·1)η of hexagonal columnar crystals. For the deposit more than 1.0 ms, the granular crystals from both on the (00·1)η and {10·0}η of hexagonal columnar crystals. The amount of granular crystals increases with the increase of off time.