what is wurtzite boron nitride?
Boron nitride is a highly versatile metal-oxide-like material with a variety of unique properties. Its uses range from thermal and chemical refractory to advanced ceramics. It is commonly found in crystal or white powder form and has the properties of good electrical resistance, high thermal conductivity, and chemical inertness.
Hexagonal boron nitride (hBN) and cubic boron nitride (cBN) are the most common forms of boron nitride. Both h-BN and c-BN have remarkable chemical and thermal stability, as well as exceptional hardness and toughness.
Cubic boron nitride has similar properties to hexagonal boron nitride, but has an unusual structure. In c-BN, the atoms of each boron and nitrogen atom are grouped into tetrahedra, and the angles between neighboring tetrahedra are different.
Wurtzitic boron nitride (w-BN) is a metastable phase of boron nitride at ordinary pressure and temperature, like hBN. It has a much lower density than h-BN, but the same mechanical properties.
It is a candidate material for diamond replacement and has many potential practical and scientific applications, such as ideal cutting/grinding/milling ferrous and carbide materials, and as an ideal dielectric substrate for optical, electronic, and 2-D graphene-based devices. It is a fascinating superhard material with a hardness next to diamond, and has a wide band gap and larger spontaneous polarization compared with GaN and AlN, which makes it an ideal candidate for III-V group wide-band-gap electronics.
The indentation strength of w-BN is 114 GPa, which is 18% stronger than diamond’s 97 GPa. The difference between the two is mainly due to bond-flipping, which occurs when a material’s atoms rearrange themselves to resist the applied pressure better, causing their atomic bonds to flip, resulting in stronger materials.