Hydrazide sol–gel synthesis of nanostructured titanium nitride: precursor chemistry and phase evolution

Abstract

A hydrazide sol–gel (HSG) process has been developed for synthesizing nanostructured titanium nitride. The process consists of reacting titanium isopropoxide with anhydrous hydrazine in the presence of anhydrous acetonitrile to yield a solid titanium alkoxy hydrazide precursor. Gas chromatography supported by chemical analysis shows that ∼80% of the isopropoxy groups are replaced by hydrazine. The role of acetonitrile, used as a solvent in the formation of titanium alkoxy hydrazide, has been studied using thermogravimetric and mass spectrometry analyses combined with chemical analysis and Fourier transform infrared spectroscopy techniques. Crystalline TiN has been obtained after heat-treatment at temperatures above 800 °C in ultra high purity nitrogen (UHP-N₂) and UHP-Ar atmospheres. Transmission electron microscopy and specific surface area analyses revealed that the TiN powder obtained after pyrolysis in UHP-N₂ at 1200 °C consists of nanocrystalline (∼10–20 nm) particles exhibiting a high specific surface area (∼252 m² g⁻¹).