For decades, hard chromium plating (HCP) has been the engineers’ choice for wear surfaces, tools and parts subject to harsh environments.

However, health-and-safety concerns and environmental constraints have led the Bury-based Wallwork Group (www.wallworkht.com) to advocate Nitron CA — a form of chromium nitride that is said to be safer and produces a harder film with heat and chemical resistance plus a bright silver finish.

Nitron CA is claimed to be twice as hard as HCP and forms a good bond to the substrate. Deposited as an even layer, it follows the contours of the part closely and maintains coverage on edges and corners.

Sharing many of the characteristics of HCP, it is chemically unreactive and therefore stable and corrosion-resistant; it is heat-resistant and smooth, and it can be applied in high thicknesses.

This makes it suitable for wear surfaces — such as medical devices subject to frequent harsh cleaning — and for tooling, including dies and punches.

Nitron CA is applied by physical vapour deposition (PVD) under vacuum conditions, creating an even film that can vary in thickness according to the application.

Wallwork says manufactures seeking to comply with the requirements of REACH regulations in the EU and OSHA legislation in the USA can be assured that its PVD processes are “environmentally acceptable”.

Only solid, non-toxic and fully recyclable source materials are used, along with inert process gases, and there are no toxic waste products from the PVD process.