Preparation and characterization of Si3N4-TiN nanocomposite via in situ co-deposition in liquid ammonia
A new method of TiN/Si3N4 nanocomposite synthesis was described and tested. Titanium tetrachloride (TiCl4) and silicon tetrachloride (SiCl4) used as the starting materials and sodium as the reduction agent were conducted in liquid ammonia respectively. Titanium chloride and silicon chloride were reduced simultaneously and titanium nitride/silicon nitride nanocomposite powders were obtained by in-situ co-deposition at temperatures around -45℃. X-ray diffraction patterns indicate that the product was amorphous and the by-product was sodium chloride. The product powders were heated up to 1600℃ and crystallization to TiN and β-Si3N4 happened. Due to presence of TiN, the crystallization of silicon nitride in the mixture was later than that of pure silicon nitride. Transmission electron microscopy (TEM) images show the average size of powders range from 10nm to 40nm and scanning electron microscopy (SEM) images conformed that Ti and Si elements were dispersed uniformly. A green bulk nitride composite containing 20vol％TiN with the mean grain size of 100-300nm and fracture toughness of 10.1±1.1MPa.m1/2 , was obtained by spark plasma sintering (SPS) at 1500-1600℃.The effect of TiN additive on microstructure and mechanical properties of composite bulk was discussed.
titanium nitride silicon nitride nanopowders liquid ammonia in situ co-deposition
杨梅 吕明利 朱鸿民
北京科技大学冶金与生态工程学院
国际会议
成都
英文
2007-11-19（万方平台首次上网日期，不代表论文的发表时间）