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Hydrophobicity on steel-based metallic surfaces provides an advantage in limiting corrosion and debris buildup on the surface, thereby, improving the substrate performance. An experimental investigation was conducted on the development of zinc stearate and silicon dioxide coatings on the surface of hot-dipped galvanised zinc-coated steel substrates, which could be used to induce superhydrophobicity. Under optimal formulation and processing conditions, a contact angle of 146° could be produced within a 120-min processing window. This represents a reduction in processing time of 67% over previous literature using similar chemistry. In addition, we proved that costly nano silicon dioxide can be replaced by lower cost micro silicon dioxide without decreasing the performance of the coating contact angle. Under standard accelerated exposure tests, the coating was shown to reduce oxide build up by a factor of 3 compared to uncoated galvanized steel.

Changes in legislation have led to Cr (VI) being removed from manufacturing processes, something that has an effect on the production of chromium coated steel products, such as Electro Chromium Coated Steel (ECCS). Previous work has shown that a novel substrate, produced using Cr(III) in the electroplating process, requires optimisation and development to give equivalent performance to the ECCS substrate for lacquered packaging applications. The passivation and pre-treatment of stainless steel has been widely investigated through both nitric acid and citric acid, showing that citric acid is a viable alternative for promoting the dissolution of anodic surface contaminant. As part of the development of a Cr(III) plated steel substrate, shown here is work investigating the use of citric acid as a pre-treatment for the developmental substrate, to improve adhesion performance of a lacquer through the sterilisation process. Through optimising the conditions by which pre-treatment in citric acid is conducted, the adhesion quality of an organic lacquer can be substantially improved, owed to the changed in chemical and physical surface characteristics induced by the process.

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