Technology meets sustainability – Nickel-free Coatings for Luxury Goods

COVENTYA has a strong dedication for developing sustainable processes and for avoiding hazardous and polluting substances as shown in the last issues of this article series. Now, while talking about sustainable and green chemistry, it is important not to forget about the humans as part of nature. While in many of our applications it is mostly the global impact of coatings and process chemistry which is in the focus of sustainable development, there are also some applications where a coating has direct long-term contact with the human body. These coatings need to fulfil strict requirements for the resistance against chemical and physical influences (e.g. sweat and abrasion) without becoming harmful to the end consumer and preserving their decorative appearance at the same timeIn precious metal applications for coatings as underlayers for gold the avoidance of copper diffusion and the potential of nickel leaching are the two main requirements. With nickel allergy prevalent it is less and less accepted to have any nickel in the coating sequence for jewellery or luxury consumer goods. COVENTYA developed several processes to replace nickel in decorative precious metal coating sequences by maintaining or exceeding the performance of the conventional coatings. Most notable is a patent pending quaternary bronze process “AURALLOY SHILED” which possesses an impressive resistance against aggressive media and can even withstand exposure to concentrated nitric acid without discoloration. The cost of the coating is meanwhile significantly lower than a coating sequence containing a Palladium barrier (the easy but expensive nickel replacement). Another patent pending solution for the replacement of nickel is the smart combination of bronze layers, which utilizes a thermodynamic phenomenon found by our researchers in an elaborate scientific study. For example, with nickel leaching standards like EN ISO 1811 being applied for more and more applications beyond jewellery (e.g. automotive decorative coatings) there is further technological development to come and COVENTYA is ready to tackle the challenges by utilizing our expertise which is already now carried around by the men and women with finer taste.