Harder than diamonds
Diamonds are immensely useful in drilling and grinding. This is because they are the hardest substances known to us. Now, a new compound developed by scientists at the Institute of Superhard Materials, Ukraine, could give diamonds tough competition. The new material, cubic boron carbonitride, is almost as hard as synthetic diamond and may be cheaper to make. Cubic boron nitride, a similar compound, has been used in place of diamonds in certain applications since 1956. Boron carbonitrides are also well known but they exist in the softer forms, just like carbon exists as graphite as well as diamond. Scientists in Ukraine squeezed the soft boron carbonitrides at pressures that were ten times those needed to make synthetic diamond. The result was a new form of boron carbonitride in which the atoms are arranged in the same manner as diamond (Applied Physics Letters , Vol 78, p1385).