ESTUDO DA DISTRIBUIÇÃO DE FASES Fe-Zn EM REVESTIMENTOS GALVANNEALED UTILIZANDO A TÉCNICA GDOES

Galvannealed (GA) coatings are composed of Fe-Zn phases, being its quality greatly affected by the phase’s distribution, making it important to be characterized. Glow Discharge Optical Emission Spectroscopy (GDOES) technique allows a quick and accurate evaluation of the chemical composition profile along the coating thickness. In this study, GA coatings were produced varying the temperature (530°C, 550°C, 580°C) and times (0 s, 5 s, 15 s, 60 s) of galvannealing treatment, in order to change the Fe-Zn phases distribution. The coatings were characterized by SEM and XRD. GDOES analyses were performed to identify the distributions of Fe and Al and correlate them with the η, ζ, δ and Γ phases. It was found that variations in temperature and treatment time influenced the distribution of Fe and Al. For short times, Fe and Al were concentrated near the coating/substrate interface and as the time increase concentrations became more uniform along the coating. The characterization of GA coatings from the Fe and Al distribution were effective for checking the distribution of Zn-Fe phases