Green tea provides a more effective and environmentally-friendly method of preparing computer hard disks, say US scientists.Inside a hard drive a component known as a read-write head is used to magnetically impart and retrieve information from a spinning disk. The point of this head must be extremely smooth as it travels on a microscopically thin layer of air above the disk’s fast-moving surface.In fact, imperfections larger than 10 angstroms (a billionth of a metre) may interfere with the normal operation of the head.So manufacturing a new read-write head involves smoothing it using a diamond instrument before using abrasive chemicals to remove any particles that still cling to the newly polishing surface.But John Lombardi, at Ventana Research based in Tuscon, Arizona in the US, suspected that green tea might also provide be an effective compound for polishing magnetic read-write heads. This was because tannin, a chemical that gives tea and coffee a bitter taste, binds to certain ceramic and metal materials. It is this quality that causes it to stain teapots and mugs.
