L. Dzib‐Pérez, J. González‐Sánchez, T. Pérez, A. Juárez and P. Bartolo‐Pérez
To study the corrosion resistance of the novel alloy Al‐12.6La (wt%) manufactured using directional solidification.
Abstract
Purpose
To study the corrosion resistance of the novel alloy Al‐12.6La (wt%) manufactured using directional solidification.
Design/methodology/approach
Samples fabricated using the Bridgman growth technique at three different withdrawal velocities were subjected to total immersion tests in distilled water and in 3.5 per cent NaCl solution and to DC polarisation tests in distilled water. XPS analyses conducted on samples after polarisation indicated the presence of an La compound in the non passive corrosion products film formed.
Findings
Anodic polarisation induced dissolution of the alloy with the formation of a non passive corrosion product film. During potentiodynamic polarisation, a sudden current increment occurred at a potential value that was more positive for samples solidified at higher rates. The corrosion resistance of this Al‐12.6%La alloy decreased as the solidification rate increased.
Originality/value
The results presented in this work are an insight to the understanding of the corrosion resistance and electrochemical behaviour of this alloy for future engineering applications and development.
Details
Keywords
Simbarashe Fashu and Rajwali Khan
Thin coatings are of great importance to minimize corrosion attack of steel in different environments. A review of recent work on electrodeposition and corrosion performance of…
Abstract
Purpose
Thin coatings are of great importance to minimize corrosion attack of steel in different environments. A review of recent work on electrodeposition and corrosion performance of Zn-Ni-based alloys for sacrificial corrosion protection of ferrous substrates is presented. The purpose of this study is to provide a systematic comparison of the corrosion resistances of Zn-Ni alloy coatings. The review contains key and outstanding comparisons of references for the period from 2007 to 2017. Binary and ternary Zn-Ni-based alloys were compared and contrasted to provide a good knowledge basis for selection of best coating system to steel substrates.
Design/methodology/approach
This article is a review article.
Findings
Zn-Ni-(X) alloys show great potential for replacing Cd metal in corrosion protection of steel substrates.
Practical implications
The research on plating of binary Zn-Ni alloys from aqueous electrolytes is now well advanced and these alloys show improved corrosion resistance compared to pure Zn. Pulse plated and compositionally modulated multilayer Zn-Ni alloy coatings showed enhanced corrosion properties compared to direct plated Zn-Ni coatings of similar composition.
Originality/value
The work on electrodeposition of Zn-Ni based alloys from ionic liquids is still scarce, yet these liquids show great promise in improving corrosion resistance and reducing coating thickness when compared to aqueous electrolytes. Advanced plating techniques in ionic liquids such as electromagnetic, compositionally modulated multilayer, pulse plating, ternary alloys and composites should be considered as these electrolytes avoid water chemistry and associated defects.