Optimisation of a hot-dip galvanising process: minimising zinc consumption with silver additions

Abstract

The addition of silver to the bath of molten zinc in the hot-dip galvanisation process, affects the morphology and the microstructure of the resulted coatings on the surface of the given steel. The effectiveness of the obtained coatings was controlled by physical and chemical parameters of technical procedure: 1 bath temperature 2 immersion time 3 withdrawal speed 4 addition of silver. Our results showed that there is a serious opportunity to optimise the galvanising process at a minimum thickness playing on the physical parameters and silver addition. It was found that galvanisation of reactive steel with molten zinc and silver produces coatings having four phases (Gamma, Delta, zeta and eta) and characterised by: bright and smooth surface with numerous visible, and small sized spangles.