Showing 2 results for Galvanizing
A. Nasr-Esfahany and M.heydarzadeh Sohi,
Volume 23, Issue 2 (1-2005)
Abstract
Zinc-Nickel electrodeposits have been widely adopted for surface treatment of automobile steel sheet for high corrosion resistance. In this work the effect of pulse parameters on the Zn-Ni alloy electrodeposits was investigated. The hardness, thickness, corrosion resistance and composition of deposits thus produced were investigated. The surface topography of the deposits was also observed in SEM and results are reported. It has been shown that the thickness of the pulse electrodeposits
was almost even. The hardness in the pulse electrodeposits increased by increasing the on-time period and by decreasing the current density. It was also noticed that increasing the on-time period increases the nickel content of the deposit. Pulse electrodposits had fine structure and the structure become finer by reducung the on-time period and pulse frequency. The corrosion dehaviors of the deposits were then investigated. The results showed that the corrosion resistance of the DC electrodeposits improves in their nickel content increases. Pulse electodeposits show the same behavior, but deposits with about 13% nickel show maximum corrosion resistance.
A. Azimi Dastgerdi, F. Ashrafizadeh, M. R. Toroghinejad, F. Shahriari , H. Zahraei,
Volume 30, Issue 2 (12-2011)
Abstract
In this paper, bare spot defects in hot-dip galvanized sheets were studied in terms of the microstructure and their influence on the corrosion and mechanical properties. Surface characteristics and microstructural features were examined by scanning electron microscopy equipped with energy dispersive spectroscopy microanalysis system. The results showed that the major cause of the bare spots was the lack of wetability of the sheet surface due to contamination, improper heat treatment or chemical composition. Corrosion resistance was evaluated by standard salt spray test. Mechanical properties were examined by tensile testing. The time to red rust was much shorter on the bare spots as compared to other regions, but it appeared that bare spot defects had no significant effect on the mechanical properties of the galvanized steel sheets.
