Study of intermetallic phases growth in a hot-dip galvanizing process by SEM

P.R. SERÉ; J.D. CULCASI; C.I. ELSNER; A.R. DI SARLI

SCANNING

JOHN WILEY & SONS INC

Lugar: New York; Año: 1997 vol. 19 p. 244 - 245

0161-0457

Affected by the electrochemical activity as well as by the diffusion and subsequent cooling processes, the complex structure of layers comprising a galvanized coating differs substantially not only in chemical composition but also in physical and mechanical properties. Furthermore, small differences in coating composition, bath temperature, immersion time, cooling rate, and substrate characteristics give rise to significant changes in the coating appearance and properties. An Al-rich layer is formed when a steel plate is brought into contact with a zinc bath containing >0.1%Al. This layer is thought to hinder the alloying between the steel sheet and molten zinc, and is therefore referred to as the inhibition layer, since it inhibits the formation of Fe-Zn phases (?Gamma?, ?Delta? and ?Psi?). The aim of the present work was to analyze the influence of both the cooling rate and the base steel roughness on the Al-rich phase growth.