Machinable Ceramic

This rectangular sample of tough white ceramic looks like plastic, but its weight and the glassy chink sound it makes when two pieces are tapped together, give away that it is not. However this is not your ordinary, china-mug-type ceramic. One of the distinctive features of traditional ceramics is that it cannot be worked or shaped once it has been fired, but this material can be machined with ordinary metal cutting tools. The kind of ceramic you would have in your kitchen is obviously very brittle – imagine trying to cut that with an electric saw! This material is a special engineered glass-ceramic, produced in two stages by first casting glass, and then heating that glass with additives that control the way it crystallises. This causes it to have some of the properties of a ceramic, and some of a glass. Although it might seem counter-intuitive, this combination of materials makes the final material much tougher and more shatter-proof than either a standard glass or ceramic, as well as yielding interesting properties like biocompatibility (glass ceramics can be used as scaffolding for tissue engineering). Because glass-ceramics can withstand very high temperatures and are resistant to chemical attack, this material can be used to make very tough parts for tasks that metals and polymers cannot manage.