TWI Frequently asked questions

What is the Keronite ® process?

by Dave Harvey and Suman Shrestha

Keronite process in action
Keronite process in action
Keronite is a new, electrolytic surface treatment for aluminium, magnesium and titanium alloys. It transforms the metal surface to a hard, dense and adherent metal oxide ceramic layer.

The process involves electrolytic oxidation of the surface of components (immersed in an aqueous, phosphate-based solution) which produces a hard, dense and adherent layer of metal oxide ceramic, typically 5 to 200µm thick.

The process enhances the wear, tribological and corrosion properties of a component surface and may be applied to surfaces of complex geometry and restricted access. Keronite is a patented process developed originally in the former Soviet Union and is now available commercially through Keronite Ltd, located at Granta Park near Cambridge, UK.

(left)
Keronite coating structure
(courtesy Keronite Ltd) 		(right)
Keronite coated components

Keronite is applied at temperatures below 100°C and, consequently, has no impact on the microstructure of the substrate material. A uniform coating thickness is applied over geometrically complex and restricted access surfaces, such as inner surfaces and holes.

A further advantage is that Keronite coated parts can be repaired easily by re-application, since Keronite is applied preferentially in areas where the coating is thinnest, and without the need to remove the remaining, un-damaged coating.

Keronite offers a commercially and technically competitive alternative to a number of widely used processes including hard anodising, electroplated hard chrome and thermally sprayed coatings. While many successful applications have been demonstrated for these more-established processes, there is a strong need to identify new coating processes that can meet the requirements of recent environmental legislation and the continual drive for better coating performance. In particular, Keronite is an environmentally clean process, using a solution that requires no significant treatment prior to disposal.

Further information

FAQ: What are the principal characteristics, properties and applications for the Keronite process?

Group Sponsored Project on Keronite. 13946: Validation of KERONITE ® - A novel hard coating for light metal alloys Copyright © 2003 TWI Ltd

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