Sheffield retains cutting edge

A CERAMIC coating one molecule thick would increase the life of kitchen knives and other blades by up to 10 times, scientists at Sheffield University estimate, writes Nuala Moran.

They have embarked on a three-year project to carry the city's knife-making traditions into the next century. The aim of the pounds 1m project is to develop a process for applying these life-extending coatings that is cheap enough to use for mass- market knives.

Apart from being more heat-resistant, ceramic materials are stronger and more corrosion-resistant than metals. Ceramic coatings on knives make the blades stiffer and prevent metal fatigue in the underlying stainless steel.

The work is supported by Richardson Sheffield, Europe's leading knife manufacturer. The company achieved fame with its Laser knives, which are guaranteed never to need sharpening.

The patents on Laser knives will run out by 2000 and Gordon Bridges, managing director, says that Richardson needs to find an equally ground- breaking successor.

Richardson already sells a Laser knife coated with a ceramic material developed at Sheffield University, but it is a top-of-the-range niche product. The existing coating method uses sputtering techniques, which are wasteful and can only be done as a batch rather than a production-line process.

Frank Jones, of the the University's Department of Engineering Materials, intends to use plasma technology, in which an electric current is passed through a gas, causing the coating molecules to be deposited on the knife's surface.

'Using plasma technology will give very fine control over what we are depositing on the surface, probably down to a molecule-by-molecule level,' he says. The aim is to develop a process that will reduce the cost of applying the coating to a few pence per knife.

Professor Jones says the tie- up with Richardson will also advance science. 'Surface engineering is an important area, and one in which the UK is currently lagging.'