Hard work for ion implantation

AEA Technology has developed a high-tech solution to the problem of wear in mechanical components. Use of this technology, ion implantation, hardens metal surfaces and could extend the life of equipment used in the rubber, pharmaceutical, plastics and food industries.

Ion implantation was developed by AEA, and is about to make its debut in the process sector thanks to a deal with JBL FeedScrews, a specialist manufacturer of moulding and extrusion screws, barrels and dies for use across the process sectors.

The process involves directing a stream of high-energy ions at a component, generally which could be made of a variety of materials including stainless steel, glass, polymer. The ions' energy, which is in the kilovolt range, embeds them in the component's surface to a depth of about 10 microns, which changes its physical properties. For example, explains Jim Hey of AEA, nitrogen ions will make a surface harder, while carbon will reduce friction. It is preferable to adding specialised coatings to strengthen a surface, explains Hey, because it cannot chip, flake or fail.

'Trial results with ion implantation show a wear pattern that meets or exceeds anything currently on the market,' adds JBL managing director John Leask.

'Ion implantation started out in the semiconductor field and at the high-tech end of the engineering market it's still used to harden engine components for racing cars,' says Hey, 'but now we feel that we can bring its advantages to the process sector.' And the advantages are striking. Using nitride molecules, the near-surface hardness of a sample is almost doubled, says Hey; component lifetime can be extended four to five times, he adds.