Comparison of Corrosion Performance of Zn and Zn/Al 85/15 Coatings Produced by TWEA

Abstract

Zn and Zn/Al 85/15 coatings are produced at optimum conditions by twin wire electric arc (TWEA) spraying technique and are used in various industrial applications to improve corrosion protection. As an alternative for Zn coating, Zn/Al 85/15 alloys coating show very good corrosion resistances and can protect substrate materials against harsh corrosive environments. The weight ratio of 85 Zn and 15 Al is regarded as optimum value. The forms of coating material are wires with different diameters. The aim of this study is comparison of anticorrosion performance of Zn and Zn/Al 85/15 coatings on ductile iron pipe surfaces as protective coatings against corrosion. Test samples were prepared from Zn and Zn/Al 85/15 coated ductile iron pipes. Coatings were investigated by optical microscopy, scanning electron microscopy (SEM) and have been analyzed by energy dispersive Xray spectroscopy (EDS) and X-ray diffraction (XRD). They were compared according to protection performance against corrosion in salt spraying test according to ASTM B117. As a result of this study, Zn/Al 85/15 coating showed clear anticorrosion protection capacity against Zn coatings.