Influence of B source materials on the synthesis of TiB_2-Al_2O_3 nanocomposite powders by mechanica

• 作 者: Majid Abdellahi Javad Heidari Rahman Sabouhi
• 机 构: Materials Engineering Department,Islamic Azad University,
• 出 处: International Journal of Minerals Metallurgy and Materials
• 发表日期: 2013年12期
• 关键词: powders milling alloying lubricant boron completed monitored crystallite attract

An Al2O3-TiB2 nanocomposite was successfully synthesized by ball milling of Al,TiO2 and two B source materials of B2O3(system(1))and H3BO3(system(2)).Phase identification of the milled samples was examined by Xray di?raction.The morphology and microstructure of the milled powders were monitored by scanning electron microscopy and transmission electron microscopy.It was found that the formation of this composite was completed after 15 and 30 h of milling time in systems(1)and(2),respectively.More milling energy was required for the formation of this composite in system(2)due to the lubricant properties of H3BO3 and also its decomposition to HBO2 and B2O3 during milling.On the basis of X-ray di?raction patterns and thermodynamic calculations,this composite was formed by highly exothermic mechanically induced self-sustaining reactions(MSR)in both systems.The MSR mode took place around 9 h and 25 h of milling in systems(1)and(2),respectively.At the end of milling(15 h for system(1)and 30 h for system(2))the grain size of about 35-50 nm was obtained in both systems.

An Al2O3-TiB2 nanocomposite was synthesized by ball milling of Al, TiO2 and two B source materials of B2O3 (system (1)) and H3BO3 (system (2)). Phase identification of the milled samples was examined by Xray di? Raction The morphology and microstructure of the milled powders were monitored by scanning electron microscopy and transmission electron microscopy. It was found that the formation of this composite was completed after 15 and 30 h of milling time in systems (1) and (2), respectively .More milling energy was required for the formation of this composite in system (2) due to the lubricant properties of H3BO3 and also its decomposition to HBO2 and B2O3 during milling. On the basis of X-ray di? Patterns and thermodynamic calculations, this composite was formed by highly exothermic mechanically induced self-sustaining reactions (MSR) in both systems. MSR mode took place around 9 h and 25 h of milling in systems (1) and (2), respectively. At the end of milling (15 h for system (1) and 30 h for system (2)) the grain size of about 35-50 nm was obtained in both systems.