Move on mobiles

A new manufacturing technique devised at Warwick University means that scientists can now create high-tech ceramics to guard against dangerous microwaves from mobile phones, but without the risk of producing cancerous byproducts in the process.

Researchers in the university's process technology group have devised the technique for creating spun-fibre-based ceramics. It relies on spinning ceramics from solution, as opposed to using heat to form the fine fibres.

Spun, fine fibre ceramics, unlike bulk forms of ceramics, are strong and flexible and do not irritate the skin. They can be used in a host of applications, from forming the walls of high-temperature furnaces to acting as microwave shields for use with mobile phones.

However, ceramic fibres finer than one micron in diameter are suspected carcinogens, while those finer than three microns are respired in the lungs.

Traditional methods of fibre production, which involve pulling the fibre from a molten state, give fine fibres of varying diameters, and even the best current materials contain a large proportion of fibres which can be respired.

However, the Warwick team was keen to achieve the desirable properties of fine ceramic fibres in an absolutely safe product. They therefore turned their attentions to the Sol-Gel blow-spinning technique, which involves spinning fibres from an aqueous solution.

"Pulling fibres from the solution means we can produce strands with a much narrower diameter distribution," explains Ashok Bhattacharya, director of the group. "This enables us to make fibres which do not fall within the region harmful to the lungs. The technology also allows us to create fibre compositions unobtainable by other means."