In Situ Growth of a Novel Nanoscaled Rock Salt Titanium Zirconium Nitride Phase in a Silicon Nitride Matrix

Abstract

The first demonstration of a nanoscaled titanium zirconium nitride (TiZrN2) single-phase isolated during the formation of precursor-derived silicon nitride (Si3N4) matrix nanocomposites is highlighted in the present paper. We employed polymethylsilazane (PMSZ) as a Si3N4 precursor, which was chemically modified with Zr[N(CH2CH3)2]4 and Ti[N(CH3)2]4, ammonolyzed and pyrolyzed under ammonia (1000 °C) then annealed in flowing nitrogen (1500 °C). The TiZrN2 phase grew in the temperature range 1000-1500 °C and was isolated - because of its confinement into a Si3N4matrix - as a nanoscaled rock salt structure after annealing at 1500 °C as shown by X-ray diffraction. HRTEM investigations confirmed the unique nanostructural feature of the nanocomposites made of TiZrN2 nanocrystals with a size as low as 9 nm distributed in a- and b-Si3N4 phases.