Preparation and modification of nano-sized Al_2O_3 powders through addition of oxide

• 作 者: 陈勇 吴玉程 宋振亚 王文芳
• 机 构: School of Materials Science and Engineering Hefei University of Technology Hefei 230009 China,Schoo
• 出 处: Transactions of Nonferrous Metals Society of China
• 发表日期: 2005年S3期
• 关键词: sized powders dispersed adding amorphous appearance hasbeen dried gathering dist

Ammonium aluminum carbonate hydroxide(AACH), the precursor of α-Al_2O_3, was fabricated with NH_4Al(SO_4)_2 and NH_4HCO_3 via a precipitation method. During the heat treatment AACH undergoes such a phase transformation process: amorphous(350℃)→γ(700℃)→γ+θ(1050℃)→θ+α (1100℃)→α (1200℃). Oxides, such as TiO_2 sol and MgO sol were introduced into the precursor. Then both the α transformation temperature and the particle sizes of α-Al_2O_3 are decreased. The microstructures and its surface electronic properties of the powders are modified, and its dispersion property is improved. Doping TiO_2 sol grains, AACH completes α phase transformation nearly at 1100℃, its first-order diameter is about 120nm. Doping with MgO sol grains, α phase transformation completes after being sintered at 1100℃.

Ammonium aluminum carbonate hydroxide (AACH), the precursor of α-Al_2O_3, was fabricated with NH_4Al (SO_4) _2 and NH_4HCO_3 via a precipitation transformation. AACH undergoes such a phase transformation process: amorphous (350 ° C) → γ (700 ℃) → γ + θ (1050 ℃) → θ + α (1100 ℃) → α (1200 ℃). Oxides, such as TiO_2 sol and MgO sol were introduced into the precursor. Then both the α transformation temperature and the particle sizes of α-Al 2 O 3 are decreased. The microstructures and its surface electronic properties of the powders are modified, and its dispersion property is improved. Doping TiO 2 sol grains, AACH completes α phase transformation at 1100 ℃, its first-order diameter is about 120nm. Doping with MgO sol grains, α phase transformation completes after being sintered at 1100 ℃.