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Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula BN. ... Its hardness is 46 GPa, slightly ...
boron: 9.3-9.5 [3] 4900-5800 [4] 6: C: carbon (graphite) 0.5: 6: C: carbon (diamond) 10.0: 11: Na: ... Mohs scale of mineral hardness; Mohs hardness of materials ...
Some solid substances that are not minerals have been assigned a hardness on the Mohs scale. Hardness may be difficult to determine, or may be misleading or meaningless, if a material is a mixture of two or more substances; for example, some sources have assigned a Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals ...
The intrinsic group includes diamond, cubic boron nitride (c-BN), carbon nitrides, and ternary compounds such as B-N-C, which possess an innate hardness. Conversely, extrinsic materials are those that have superhardness and other mechanical properties that are determined by their microstructure rather than composition.
Its color ranges from black to brown and gold, depending on the chemical bond. It is one of the hardest known materials, along with various forms of diamond and other kinds of boron nitride. Borazon is a crystal created by heating equal quantities of boron and nitrogen at temperatures greater than 1800 °C (3300 °F) at 7 GPa (1 million lbf/in 2).
In one test, the lowest tested load of 0.49 N yielded the average hardness of 48 ± 5.6 GPa and a maximum hardness of 55.5 GPa, which is comparable to the hardness of cubic boron nitride (c-BN) under an equivalent load. [5] Such phenomenon of inverse relationship between the applied load and hardness is known as the indentation size effect. [5]
A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific comparison table for steels .
Monolayer boron nitride has an average Young's modulus of 0.865 TPa and fracture strength of 70.5 GPa. In contrast to graphene, whose strength decreases dramatically with increased thickness, few-layer boron nitride sheets have a strength similar to that of monolayer boron nitride. [12] Thermal conductivity.