Cadmium Replacement Using Pulse Plating And Ionic Liquids (CRUPPAIL)

Cadmium coatings have long been the preferred method for protecting components from corrosion in many critical applications across many strategically important industry sectors. Unfortunately, cadmium is toxic and, in recent years, there has been increasing legislation introduced to proscribe its use in many applications. Consequently, protective metal coatings suppliers have developed replacement processes that use less hazardous materials, and which aim to provide similar levels of protection. Of these replacement coatings, zinc-nickel alloys have been reasonably successful, but they are expensive and their performance is still inferior to cadmium in many applications. These alloy coatings are formed via an electroplating process using water-based solutions and the application of a direct current. In this project, the coatings will be deposited from novel, low cost, environmentally friendly materials known as ionic liquids. The project team has already shown that metal coatings deposited from ionic liquids can have superior properties to those deposited from aqueous solutions. In addition, instead of using conventional direct current electroplating, advanced digital (pulse plating) current control will be used, as this technique is also known to provide improved coating qualities. The partners have experience of using both ionic liquids and pulse plating to develop advanced coatings and, in this project, the two approaches will be synergistically combined in a new, reduced cost,high performance zinc-nickel plating process that will directly replace cadmium and offer competitive benefits to UK industry.