Pu Sanxu, Li Lu, Ma Ji, Lu Fuliang, Li Jiangong
Institute of Materials Science &Engineering, Lanzhou University, Lanzhou 730000, China.
Sci Rep. 2015 Jul 13;5:11575. doi: 10.1038/srep11575.
Disperse fine equiaxed α-Al2O3 nanoparticles with narrow size distribution are important materials in nanotechnology and nanomaterials, but syntheses of disperse fine equiaxed α-Al2O3 nanoparticles usually result in fine γ-Al2O3 nanoparticles or large α-Al2O3 nanoparticles larger than 15 nm. α-Al2O3 has a higher surface energy than γ-Al2O3 and becomes thermodynamically not stable with respect to γ-Al2O3 at specific surface areas larger than 100 m(2)/g (at sizes smaller than 15 nm for spherical particles) at room temperature. So disperse fine equiaxed α-Al2O3 nanoparticles smaller than 15 nm with narrow size distribution are extremely difficult to synthesise. Here we show the successful synthesis of disperse fine equiaxed α-Al2O3 nanoparticles with average sizes below 10 nm and narrow size distribution by selective corrosion and refined fractionated coagulation separation. An almost fully dense nanocrystalline α-Al2O3 ceramic with a relative density of 99.5% and an average grain size of 60 nm can be sintered from disperse fine equiaxed α-Al2O3 nanoparticles with narrow size distribution.
尺寸分布窄的分散性良好的等轴α-Al2O3纳米颗粒是纳米技术和纳米材料中的重要材料，但合成尺寸分布窄的分散性良好的等轴α-Al2O3纳米颗粒通常会得到细小的γ-Al2O3纳米颗粒或尺寸大于15nm的大尺寸α-Al2O3纳米颗粒。α-Al2O3的表面能高于γ-Al2O3，在室温下，当比表面积大于100 m²/g（对于球形颗粒，尺寸小于15nm）时，相对于γ-Al2O3，α-Al2O3在热力学上变得不稳定。因此，合成尺寸小于15nm且尺寸分布窄的分散性良好的等轴α-Al2O3纳米颗粒极其困难。在此，我们展示了通过选择性腐蚀和精细分级凝聚分离成功合成平均尺寸低于10nm且尺寸分布窄的分散性良好的等轴α-Al2O3纳米颗粒。由尺寸分布窄的分散性良好的等轴α-Al2O3纳米颗粒可以烧结出相对密度为99.5%、平均晶粒尺寸为60nm的几乎完全致密的纳米晶α-Al2O3陶瓷。
