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中南大学学报(自然科学版)

Journal of Central South University

第35卷    第4期    总第158期    2004年8月

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文章编号:1672-7207(2004)04-0527-05
纳米粉体大气环境团聚机理及
无团聚纳米粉体的制备
李国栋1,2,熊 翔1,黄伯云1

(1.中南大学粉末冶金国家重点实验室,湖南长沙,410083;
2.襄樊学院土木工程系,湖北襄樊,441003
)

摘 要: 分析了纳米粉体的表面结构与粉体间相互作用,研究了大气环境下纳米粉体的团聚机理及防止纳米粉体团聚的方法。研究结果表明:高的比表面积和表面能是纳米粉体团聚的强大动力,但常温下洁净粉体表面的本身结构调整不会导致纳米粉体团聚,只会导致其分散;外来物质(如空气、水等)在表面发生化学吸附与化学反应后,改变了表面结构和相互作用性质,在粉体表面生成具有羟基等新结构,导致粉体间相互吸引(如氢键间的作用力)与化学反应(如—OH基间聚合反应)等行为,是大多数纳米粉体团聚的真正原因。此外,还从原理上论述了真空状态、惰性气体保护及表面改性适合于无团聚纳米粉体的制备方法。

 

关键字: 纳米粉体;团聚机理;分散机理;表面结构;制造

Agglomerate mechanism of nanometer
powders in atmosphere and methods of preparation
of nan-agglomerate nanometer powders
LI Guo-dong1,2,XIONG Xiang1,HUANG Bo-yun1

1.State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China;
2.Department of Architectural Engineering, Xiangfan University, Xiangfan, 441003 China

Abstract:Agglomerate mechanism of nanometer powders was studied by analysing the surface structure and the interaction between powders in atmosphere. The results show that the adjustment of surface structure on the clean nanometer powders does not cause agglomeration but dispersion, although high specific area and surface energy are the main power of agglomeration. A new surface structure with hy-droxyls(-OH) is formed while chemical adsorption and chemical reaction occure due to outside substance such as air and water. The attraction between nanometer powders because of the action between the hydroxyls(—OH) and the chemical reaction of the hydroxyls are the principal reasons of serious agglomeration of nanometer powders in atmosphere. The methods and mechanisms of preparation of non-agglomerative nanometer powders are disscussed. Vacuum, inert gas treatment and surface modification are suitable for preparation of non-agglomerate nano-powders.

 

Key words: nanometer powder; agglomerate mechanism; disperse mechanism; surface structure;
Preparation

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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