particle size analysis (rus. гранулометрия otherwise гранулометрический анализ) — (from Latin granulum “grain”) set of methods for measuring and analysing the size distribution of isolated particles and instrumentally detected morphological fragments of solids (crystallites, aggregates, agglomerates, grains).

Description

The first instrumental method of grain size analysis was the sieve analysis, in which the analysed powder or slurry (suspension) was passed through a series of screens with progressively smaller mesh sizes. Thus, a mixture containing particles of various sizes can be divided into fractions, whose size limits are determined by the mesh size of two adjacent sieves. Then the factions are weighted to construct a diagram of the mass particle size distribution, in which the fraction size range is plotted on the horizontal axis, and its mass content in the powder sample on the vertical axis (see grain size distribution); the resulting graph is the fractional composition histogram. The histogram has become a traditional form of representing grain size distribution in this type of analysis and it continues to be used in other methods of grain size analysis. The sieve analysis is suitable only for particle sizes exceeding several tens of microns; smaller particles can be studied with use of sedimentation in the natural gravitational field or under the influence of centrifugal forces. Interaction between the particles and between the particles and the dispersion medium has great effect on the particle deposition rate, and, consequently, on the results of the grain size analysis with use of this method. These processes are studied by colloid chemistry.

The most common methods of grain size analysis of nanoparticles include dynamic light scattering techniques based on the dependence of the light scattering efficiency in a dispersion medium on the size of the optically opaque particles that make up this medium; and methods of electron and atomic force microscopy allowing to analyse not only the size distribution of powders, but also of bodies consisting of agglomerated grains, such as films and ceramics. The latter methods use statistical analysis to obtain reliable size distribution data on the basis of individual images. The particle size analysis also makes up an important section of metallography that usually applies optical microscopy to obtain necessary data, which limits the size of analysable objects to several hundreds of nanometres.

Author

  • Shlyakhtin Oleg A.

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