Researchers develop hard nanomaterial to rival diamonds
Diamonds are not only a girl's best friend: as the hardest known natural material, they are also coveted by industry for use in applications such as mining and drilling. Now, French and German researchers have come up with a non-carbon material, which they claim is almost as hard as a diamond. The material, which is made out of thermodynamically stable boron nitride, is also much more resistant to fractures and wear than a polycrystalline diamond. The team, composed of researchers from Universities of Heidelberg, Bayreuth, Paris and Grenoble, developed the new material by reducing the size of boron nitride grains from micron to nanoscale. Using a 5,000 tonne scientific press, the boron nitride was then synthesised at a range of high pressures and temperatures. Several boron nitride materials with different-sized grains were tested by the researchers, using high-resolution transmission electron microscopy to characterise the structure of the nanomaterial. This is not the first time that crystalline cubic boron nitride has been considered for uses similar to those of diamonds. Not only can it withstand high temperatures- up to 1,650 kelvin (K) compared to just 950K for diamonds - it is also a super abrasive. As early as the 1950s, the material was used in industrial applications similar to those of diamonds, such as processing various kinds of hard and tough steels. However, crystalline cubic boron nitride has never been able to replace diamonds completely because its hardness is half that of a diamond (50 GPa compared to 100 GPa). Although the hardness of new material developed by the French and German team is still lower than that of a diamond (85GPa), the researchers believe that the discovery will lead to the development of even harder, tougher and more thermally stable materials that could one day rival the diamond.
Countries
Germany, France