Morphology and tensile strength of titanium nitride whiskers

TiN whiskers were synthesized using K2TiF6 as a starting material and B2O3 as an additive. The largest amount of TiN whiskers was deposited when 1 mmol of B2O3 was placed in a graphite boat (1), a mixed powder containing K2TiF6 and B2O3 was placed in another boat (2), and then they were both heated at 1400 degrees C for 10 h. B2O3 evaporated was considered to accelerate the thermal decomposition of alumina tube, investigating the effect of addition of B2O3. Scanning electron microscopy and transmission electron microscopy of the obtained whiskers revealed that most of the whiskers were square prismoidal shaped and some were hexagonal or octagonal prismoidal shaped. The square and octagonal prismoidal whiskers grew in the [100] direction and the hexagonal prismoidal whiskers grew in the [111] direction. As in the case of whiskers synthesized from other materials, the tensile strength of the whiskers increased with decreasing cross-sectional area of the whiskers, indicating the size effect.