nanopowder (rus. нанопорошок) — today, this term may be defined in several ways: 1) as defined by the International Standardisation Organisation (ISO), nanopowder is a solid powder-like substance of artificial origin that contains nanoobjects, aggregates or agglomerates of nanoobjects or a combination thereof; 2) an assembly of nanoparticles; 3) a powder, all particles of which are smaller than 100 nm.

Description

Nanoscale grains are contained, to a certain extent, in most submicron powders, but their content is usually very insignificant. The presence of these nanodisperse particles does not mean that the entire volume of such powders may be referred to as “nanopowders”. In certain types of nanopowders, submicron agglomerates are made up of nanoscale crystallites and/or blocks, but they may break down into separate nanoparticles under certain physical effects (e.g., ultrasonic disintegration, mechanical activation, etc.).

Nanopowders are characterised by:

-mean size of particles and size distribution of particles;

-mean size of crystallites and size distribution of crystallites;

-rate of agglomeration of particles (in case of weak agglomeration, particles hold together due to Van der Waals type of interactions, while strong aggregation is characterised by strong bonding of particles);

-specific area of the surface;

-chemical composition of a bulk of particles;

-sectional composition for core-shell particles;

-morphology of particles;

-chemical composition of the surface;

-crystalline structure of nanoparticles;

-content of moisture and other adsorbates;

-looseness (flow properties);

-packed density;

-colour.

Authors

  • Gusev Alexander I.
  • Ivanov Victor V.

Source

  1. NanoDictionary // Nanotechnology Perceptions. 2005. №1. P. 147–160.

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