Novel zirconium nitride precursor: Synthesis, decomposition pathway, and pyrolysis of [(CH₃)₃Si]₂NH·ZrCl₄

The reaction of hexamethyldisilazane with zirconium tetrachioride furnishes an adduct, [(CH₃)₃Si]₂NH·ZrCl₄, which is soluble in dichloromethane. The decomposition of [(CH₃)₃Si]₂NH·ZrCl₄ proceeds with the elimination of trimethylchlorosilane and hydrogen chloride and is complete at 600°C. The resulting powder is amorphous zirconium nitride which is highly susceptible to hydrolysis and oxidation. The pyrolysis of the precursor in a dynamic vacuum or ammonia atmosphere at 600°C and subsequent sintering of the powder at 900°C furnishes crystalline zirconium nitride. Transmission electron microscopy of the powder shows that the particles are coated with a thin zirconium oxide layer. Crystalline zirconium nitride powder, free from zirconium oxide impurities, is obtained if the sintering is carried out at 1075°C.