Scientists develop an ultra-hard glass made using alumina

Scientists in Japan have developed an ultra-hard glass made using alumina. The new material is thin as well as hard and is made using alumina, an oxide of aluminium.

If successfully commercialised, it could increase the durability of glass used in the windows of buildings, cars and in smartphone displays.

The team from the University of Tokyo and Japan's Synchrotron Radiation Research Institute have published their findings in Scientific Reports journal.

The material belongs to a category known as oxide glasses, which mainly consist of silicon dioxide - but with their strength boosted by alumina.

However, attempts to increase the amount of alumina have faltered in the past because it would cause the mixture to crystallise when it came into contact with the sides of its container, preventing a useful glass from being formed.

Atsunobu Masuno from the Institute of Industrial Science at the University of Tokyo and colleagues used oxygen gas to push the ingredients into the air and then used lasers to melt them.

The resultant glass was colourless, transparent and extremely hard. A property called Young's modulus, which is an indicator of stiffness, was greater than that of some metals, and on its way to values associated with steel.

Another mechanical property, called Vickers hardness, was comparable with the highest values previously reported for oxide glasses.

"We will establish a way to mass-produce the new material shortly," Dr Masuno told the Asahi Shinbun newspaper. "We are looking to commercialise the technique within five years."