Boron Nitride crystallizes in a hexagonal unit cell with edge length 0.251 nm and height of the unit cell 0.699 nm. Calculate density.
Answers
Explanation:
Hexagonal Boron Nitride (hBN) is also known as ‘White Graphite', has similar (hexagonal) crystal structure as of Graphite. This crystal structure provides excellent lubricating properties. hBN is much superior to Graphite and has following characteristics:
Excellent Lubricating Properties due to low Coefficient of Friction at 0.15 to 0.70
Good Chemical Inertness
Electrical Insulator
Thermal Conductor (result: better heat dissipation)
High Temperature Stability, 1000o C in Air, 1400o C in Vacuum and 1800o C in Inert gas
Low Thermal Expansion
Low Dielectric Constant
High Load bearing properties
Non-Wetting: hBN is not wetted by Glasses, Salts and (most) metals, therefore it provides strong resistance to chemical attack Easy Machineability (in hot pressed state). Complex shapes can be machined from hot pressed structure.
hBN powders are available in following particle sizes: 70 nm, 150 nm, 0.5 micron, 1.5 micron, 5 microns to 30 microns