Synthesis and Sintering of Aluminium Nitride Nano-particles

Aluminum nitride (AlN) nano-particles were synthesized from aluminum chloride by sodium reduction in liquid ammonia. A liquid solution of sodium dissolved in ammonia was employed as a reduction-nitridation agent, which enabled direct nitridation of aluminum chloride at -45 degrees C. The synthesized particles were heat-treated at 1000 degrees C in vacuum, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy ( _LEM) and BET surface area measurement. The results indicated that the products were hexagonal wurtzite AN particles, with a specific surface area of 262 m(2)g(-1). Spark plasma sintering (SPS) process was used to consolidate the as-prepared AN nanoparticles, and dense AN ceramic (>98.5%) with average grain size of 200-400 nm was obtained at 1600 degrees C without the use of sintering additives.