Boron nitride is a chemically stable refractory material composed of one molecule each of boron and nitrogen. It is available in crystalline forms such as hexagonal boron nitride, cubic boron nitride, and wurtzite boron nitride.
Hexagonal boron nitride, also called h-BN is the most common crystalline form of boron nitride. It is soft and stable, and has been used for a wide range of industrial and commercial applications.
Cubic boron nitride, or c-BN, is another commonly applied crystalline form. It is similar to diamond and has superior thermal and chemical stability.
Wurtzite boron nitride, on the other hand, is an extremely rare crystalline form and is slightly softer than c-BN. It is known for its high heat-shock resistance and can withstand temperatures of up to 3,000 degrees Celsius without cracking.
Wurtzite boron nitride, a new superabrasive material, is produced through detonation of a mixture of boron nitride and chromium oxide. The combination of both materials creates a polycrystalline structure that provides a higher cutting rate and sharpens itself during cutting.
In a recent study, researchers found that wurtzite boron is more powerful than diamond under equal pressure conditions. They found that under a specific pressure of 152 GPa, wurtzite boron will be 57% stronger than lonsdaleite (hexagonal diamond) and 18% harder than diamond.
Moreover, wurtzite boron has a grain size of 20-30 nm, which is significantly lower than the micro-grains found in previous studies. This indicates that wurtzite boron may have been synthesized under lower pressure than previously thought.