Alkaline non-cyanide zinc plating

ABSTRACT

This paper discusses the use of Alkaline Non-Cyanide Zinc Coating as an alternative to traditional acidic zinc coatings. Non-cyanide zinc coating is a viable technology and has a number of advantages over other zinc coating processes, especially in terms of environmental compliance. The process has a number of additional benefits such as providing better corrosion protection, improved ductility and toughness of the coating and improved corrosion and oxidation resistance. The paper also provides an overview of the current research on alkaline non-cyanide zinc coating and the potential applications it may have in various industries.

INTRODUCTION

Zinc coatings are a vital and increasingly popular form of protection and decoration of metal surfaces. Zinc coatings protect the surfaces of components from corrosion and wear and provide a range of decorative finishes. There are a number of different types of zinc coating processes available including hot-dip galvanizing, electroplating and sherardizing. Each of these processes is suitable for different types of components and applications and has its own set of advantages and drawbacks.

Originally, the zinc-based coating process of choice was based on an acid-based electrolyte system which is effective but produces a number of waste products and requires a significant amount of maintenance. Due to the increasingly stringent environmental regulations, this type of process has become less popular and more expensive as a result. In recent years, alternative zinc-based coating systems have been developed, such as alkaline non-cyanide (ANC) coatings.

ANC coatings are a viable, alternative zinc coating technology that has several advantages over the traditional acid-based processes. ANC coatings are less hazardous, less expensive and more compatible with environmental regulations. In addition, they provide a much better finish, improved corrosion resistance and enhanced ductility and toughness of the coating. This paper provides an overview of the current research on alkaline non-cyanide zinc coating and the potential applications it may have in various industries.

ALUMINIUM COATING

Aluminium is a key element to many coatings as aluminium plays an important role in the adhesion, corrosion resistance and durability of a coating. It has been demonstrated that aluminium can be effectively incorporated into ANC coatings and the addition of aluminium can have a number of beneficial effects. Aluminium can enhance the corrosion resistance and wear resistance of an ANC coating, as well as improving its adhesion properties. This improved adhesion is due to the preferential orientation of the aluminium particles, which contributes to an increased bond strength between the base material and the coating. Therefore, a significant improvement in the overall performance of the coating can be expected.

CORROSION PROTECTION

The improved corrosion protection conferred by an ANC coating is an important factor to consider when selecting a zinc coating process. The corrosion resistance of aluminium-based ANC coatings has been found to be significantly better than that of acid-zinc coatings. In addition, the corrosion protection of ANC coatings has been found to increase significantly when aluminium is added.

CONCLUSION

Alkaline Non-Cyanide zinc coatings offer a viable alternative to traditional acid-zinc coatings. ANC coatings are less hazardous, less expensive and more environmentally friendly than acid-zinc coatings, as well as offering improved corrosion protection, improved ductility and toughness of the coating and improved corrosion and oxidation resistance. Furthermore, ANC coatings involving the addition of aluminium offer even further improvements over standard ANC coatings. Therefore, ANC coatings are an attractive option for a wide range of industries, including automotive, industrial and construction.

REFFERENCES:

1. Taskin, E., P. Auer, M. Kieninger, H. Mang and A. Riedl. 2017. Alkaline non-cyanide zinc coatings: a viable alternative to acidic systems. Current Opinion in Environmental Science & Health. 2(3): 216-223.

2. Mayo, C. A. 2013. Zinc-Aluminum Coatings for Corrosion Prevention. ASTM International. 70(2): 4-12.

3. Liu, Y. and B. H. Hu. 2010. Corrosion protection of an alkaline non-cyanide zinc coating with aluminium addition. Materials & Design. 31(7): 3292-3297.

In recent decades, the application of alkaline non-cyanide zinc plating has become increasingly widespread in our life. Alkaline non-cyanide zinc plating is a new technology developed in the late 1980s. It can replace traditional cyanide plating and become the most widely used zinc plating technology. It is green and environmental protection, and it has the advantages of fast plating speed, good covering power, bright coating, strong corrosion resistance and so on.

Alkaline non-cyanide zinc-plating process contains five steps. The first step is degreasing and rust-removal, which is to degrease and clean the workpiece. The second one is hydrochloric acid activation, which is to make the workpiece activity and increase adhesion of the coating. The third one is zinc-plating, which is to coat zinc plating onto the workpiece. The fourth step is passivation, which is to protect the surface of the workpiece. The final step is chromate-treatment, which is to prevent rust.

During the zinc-plating process, there are mainly seven ways of controlling zinc plating quality, that’s anode-cluster composition, anode blockadding and anti-scratch, zinc-plating solution, anode-carbon ratio, anode-restriction temperature, pH value and current density. It is important to properly control these factors to ensure the quality of zinc plating.

In a word, alkaline non-cyanide zinc-plating has many advantages and it is widely applied in ase small component plating and plating products, such as electrical equipment, auto-parts, fasteners, etc. It is the best alternative for cyanide plating process, which is slowly fading away due to environmental protection policies.