Synthesis of faceted crystal grains of titanium nitride using titanium oxides, boron nitride, and sodium

Agglomerates of faceted single crystal grains of titanium nitride (TiN) with a size of 1–100 µm were synthesized by heating TiO2, FeTiO3, or TiO and Na in a boron nitride (BN) crucible at 1000–1100 °C under an argon atmosphere. Water soluble sodium borates were also produced as a melt phase during the heating. The yield of TiN prepared from TiO2 at 1100 °C was 77%. Wavelength-dispersive X-ray analysis of the TiN single crystal grains revealed that the composition was almost stoichiometric, and the oxygen content was less than 1.2 at %. The TiN formation could be regarded as a sort of metathesis reaction, in which the oxygen of TiO2 and the nitrogen of BN were exchanged.