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

A hydrazide sol-gel (HSG) process was developed for synthesising 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 about 80% of the isopropoxy groups are replaced by hydrazine. The role of acetonitrile, used as a solvent in the formation of titanium alkoxy hydrazide, was studied using TG and mass spectrometry analyses combined with chemical analysis and FTIR spectroscopy techniques. Crystalline TiN was obtained after heating at temperatures above 800 C in ultrahigh purity nitrogen (UHP-N2) and UHP-Ar atmospheres. TEM and specific surface area analyses revealed that the TiN powder obtained after pyrolysis in UHP-N2 at 1200 C consists of nanocrystalline (about 10-20 nm) particles exhibiting a high specific surface area (about 252 m2/g). 50 refs.