Aggregate Morphology Evolution by Sintering: Number & Diameter of Primary Particles.
Aggregate Morphology Evolution by Sintering: Number & Diameter of Primary Particles.
复制标题
DOI：
10.1016/j.jaerosci.2011.11.005
复制
发表时间：
2012-04
影响因子：
4.5
通讯作者：
Pratsinis, Sotiris E.
中科院分区：
文献类型：
--
作者：
Eggersdorfer, Max L.;Kadau, Dirk;Herrmann, Hans J.;Pratsinis, Sotiris E.
分形团聚体（物理结合）和团聚体（化学或烧结结合）的结构在气溶胶合成纳米颗粒以及监测燃烧排放和大气颗粒中很重要。它还影响粒子的迁移率、散射，并最终影响纳米复合材料、悬浮液和由这些粒子制成的设备的性能。在这里，研究了非晶材料（二氧化硅，聚合物）的粘性流动和结晶陶瓷（二氧化钛，氧化铝）或金属（Ni, Fe， Ag等）的晶界扩散的聚集体烧结。在烧结过程中，平均骨料投影面积和组成初级颗粒的等效数量之间存在标度规律：从分形团块到聚集体，最后是致密颗粒（如球体）。这本质上是一种独立于时间、材料性质和烧结机制的关系。它是用来估计等效初级颗粒直径和数量的团聚体。用有效分形维数（Df）和质量迁移率指数（Dfm）及其相应的前因子来量化聚集体形态或结构的演化。在烧结过程中Dfm单调增加，对于致密颗粒趋近于3。因此，Dfm及其预因子可以用来衡量由已知碰撞机制形成的团聚体的烧结程度或程度。通过与在电炉中不同温度下烧结纳米银颗粒的实验对比，验证了上述分析结果。
The structure of fractal-like agglomerates (physically-bonded) and aggregates (chemically- or sinter-bonded) is important in aerosol synthesis of nanoparticles, and in monitoring combustion emissions and atmospheric particles. It influences also particle mobility, scattering, and eventually performance of nanocomposites, suspensions and devices made with such particles. Here, aggregate sintering by viscous flow of amorphous materials (silica, polymers) and grain boundary diffusion of crystalline ceramics (titania, alumina) or metals (Ni, Fe, Ag etc.) is investigated. A scaling law is found between average aggregate projected area and equivalent number of constituent primary particles during sintering: from fractal-like agglomerates to aggregates and eventually compact particles (e.g. spheres). This is essentially a relation independent of time, material properties and sintering mechanisms. It is used to estimate the equivalent primary particle diameter and number in aggregates. The evolution of aggregate morphology or structure is quantified by the effective fractal dimension (Df) and mass-mobility exponent (Dfm) and the corresponding prefactors. The Dfm increases monotonically during sintering converging to 3 for a compact particle. Therefore Dfm and its prefactor could be used to gauge the degree or extent of sintering of agglomerates made by a known collision mechanism. This analysis is exemplified by comparison to experiments of silver nanoparticle aggregates sintered at different temperatures in an electric tube furnace.
登录
查看更多内容
影响因子：
3.7
作者：
HASMY, A;FORET, M;JULLIEN, R
通讯作者：
JULLIEN, R
影响因子：
3.7
作者：
Buesser, B.;Groehn, A. J.;Pratsinis, S. E.
通讯作者：
Pratsinis, S. E.
DOI：
10.1111/j.1151-2916.1958.tb13519.x
发表时间：
1958-01-01
影响因子：
3.9
作者：
COBLE, RL
通讯作者：
COBLE, RL
影响因子：
5.2
作者：
Heinson, W. R.;Sorensen, C. M.;Chakrabarti, A.
通讯作者：
Chakrabarti, A.
影响因子：
2.7
作者：
Cazals, Frederic;Kanhere, Harshad;Loriot, Sebastien
通讯作者：
Loriot, Sebastien