Synthesis of titanium nitride whiskers from hexafluorotitanates(IV)

Titanium nitride [TiN] whiskers were formed on the outer surface of the graphite tube by heating sodium fluorotitanate (N) (Na2TiF6) at 1300 degrees C or higher in a stream of nitrogen gas. The shape of whiskers was observed by SEM. The cross section of mostly whiskers was square. It was assumed that these whiskers grew in the [100] direction by Vapor-Solid (VS) mechanism. The lattice constant of TiN obtained in this work was determined by XRD as 0.4243-0.4246 nm, which was larger than 0.4242 nm for that of stoichiometric TIN. This fact showed that TiN obtained in this study contained a trace of carbon. A thermodynamic interpretation of the formation of TiN is considered. It is found that the existence of C, NaF and Al2O3 in a stream of N-2 gas is necessary for the formation of TiN from Na2TiF6.