KERONITE - Revolutionary Alloy Surface Treatment Offers Breakthrough For A Wide Range of Industries

KERONITE is new surface treatment that can make light metal alloys many times harder than using conventional methods, enabling alloys to be used in applications in which only heavy steels have traditionally been appropriate.

Ceramic layers produced on Aluminium, Magnesium and Titanium by KERONITE technology: a novel Plasma Electrolytic Oxidation process, offer an attractive alternative to hard anodising and plasma or themal spraying, in wear and corrosion resistant applications as well as thermal insulation.

KERONITE is patented world-wide. The technology is being commercialised under licence by Poeton Industries Ltd & Crompton Technology Ltd in the UK, Micron Srl in Italy, Metronic GmbH in Germany and Meta Technologies Ltd in Ireland.

KERONITE surface treatment involves creating a high energy plasma discharge around a component immersed in an electrolyte that produces a ceramic surface as well as possibilities for elemental co- deposition. Electrolyte composition and process parameters can be adjusted to tailor layer hardness and roughness. The process is said to be robust and comparable with hard anodising in terms of total running costs. The electrolytes are cheaper than those for conventional anodising and, unlike many anodising solutions, contain no environmentally damaging components. They can therefore be disposed of via mains drainage systems without further treatment.

In wear-resistant applications, KERONITE surface treatment can be used at thicknesses typically between 30 to 80 µm on Aluminium alloys, and about between 20 to 40 µm on Magnesium alloys. The process produces a predictable uniform layer to be formed on complicated shapes without cracking; little surface preparation is required. Worn or damaged parts can be recoated without stripping the damaged coating. KERONITE improves the wear-resistance of bare Magnesium by 20 times and also reduces galling. KERONITE coatings can also be applied to the specialised Al-Be (AlBeMet type) alloys that are increasingly being used to save weight in aerospace and high performance automotive applications. Micro-hardness of up to 2,000 HV has been achieved on 2000 series aluminium alloys.

Because the coating is formed through a reaction that involves the substrate, adhesion is excellent. Secondary treatments include coating with PTFE to reduce friction, polymer sealants to increase corrosion resistance, and impregnation with nickel, chromium, copper, or carbides such as Cr3C2.

Ball on disc tests have shown that the adhesive wear resistance of KERONITE on Aluminium alloys, particularly 2024, is superior to that of hard chromium layers. Coated 6082 Aluminium alloy has survived over 2,000 hours in salt spray tests. The layers exhibit good thermal resistance: coatings can withstand short exposures up to 2,000ºC. KERONITE layers also provide suitable substrates for mounting electrical components.

KERONITE ceramic coatings can be effectively used for hardening Al, Mg and Ti, their alloys and inter-metallides in various areas of manufacturing, including,

Automotive - pistons, cylinder blocks, sliding bearings, fuel pumps

Aerospace - bearings and wheels, landing gear components

Textile - shuttles, spin rotors, gripping devices, thread guides, bobbins

Marine Equipment - propellers, capstan winches, guide rails

Oil, Gas & Chemical Engineering - valves, pumps, submerged oil pumps

Cookware - frying pans, saucepans, knife sharpeners

Medicine - bone prosthesis, medical mixers

Printing, Packaging & Tobacco - packaging line parts, anilox and other rolls

Robotics - pneumatic drive components, pumps and hydraulic systems