Ammonolysis Products of the Dialkylamides of Titanium, Zirconium, and Niobium as Precursors to Metal Nitrides

The dialkylamides of titanium(IV), zirconium(IV), and niobium(V) react with liquid ammonia to produce solid products of high metal content. Infrared spectroscopy and elemental analysis indicate that these ammonolysis products are nitridoor imido‐bridged polymers. Based on metal content, pyrolysis at <800°C converts these materials quantitatively to the corresponding nitride or carbonitride. The only products trapped following vacuum pyrolysis are ammonia and dialkylamine. Temperature‐programmed pyrolysis with analysis of the evolved gases by mass spectroscopy shows that the composition of the gaseous products depends on whether helium or hydrogen is used as the carrier gas. The presence of a hydrogen atmosphere compared to a helium environment or a dynamic vacuum results in a lower carbon content of the titanium and niobium products. A general reaction scheme for conversion of the precursor compounds to refractory materials is formulated from the results of the various pyrolytic experiments.