ISO 26824:2022
(Main)Particle characterization of particulate systems — Vocabulary
Particle characterization of particulate systems — Vocabulary
This document defines terms that are relevant to the characterization of particles and particulate systems. This document includes such fields as the representation of results of particle size analysis, the descriptive and quantitative representation of particle shape and morphology, sample preparation, specific surface area and porosity characterization and such measurement methods as sedimentation, classification, acoustic methods, laser diffraction, dynamic light scattering, single particle light interaction methods, differential electrical mobility analysis, image analysis and others in a size scale from nanometre to millimetre.
Caractérisation des particules dans les systèmes particulaires — Vocabulaire
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 26824
Second edition
2022-08
Particle characterization of particulate
systems — Vocabulary
Caractérisation des particules dans les systèmes particulaires —
Vocabulaire
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Terms related to representation of size and classification analysis data . 1
3.2 Terms related to representation of particle shape . 9
3.3 Terms related to pore size distribution, porosity and surface area analysis . 11
3.4 Terms related to gravity or centrifugal sedimentation methods . 17
3.5 Terms related to electrical sensing zone methods . 21
3.6 Terms related to laser diffraction methods . 21
3.7 Terms related to dynamic light scattering . 25
3.8 Terms related to image analysis methods . 26
3.9 Terms related to single particle light interaction methods .30
3.10 Terms related to small angle X-ray scattering . 32
3.11 Terms related to sample preparation and reference materials . 33
3.12 Terms related to electrical mobility and number concentration analysis for
aerosol particles . 35
3.13 Terms related to electrical charge conditioning .39
3.14 Terms related to acoustic methods . 41
3.15 Terms related to focused beam method .44
3.16 Terms related to characterisation of particle dispersion in liquids .44
3.17 Terms related to methods for zeta potential determination . 47
Bibliography .54
Index .55
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 24, Particle characterization including
sieving, Subcommittee SC 4, Particle characterization.
This second edition cancels and replaces the first edition (ISO 26824:2013), which has been technically
revised.
The main changes are as follows:
— All definition clauses have been rearranged as subclauses in Clause 3 and all terms and clauses have
been renumbered.
— Latest revisions and documents from ISO/TC 24/SC 4 have been incorporated, as well as
harmonization with ISO/TC 229 general definitions.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
Since the last revision of this document in 2013, about 24 ISO standards have been published by
ISO/TC 24/SC 4 and about 15 projects are currently under construction together with the 5-year
revision of the existing standards. Therefore, terms and definitions of each standard, which are relevant
for other standards should be collected and adjusted to a uniform nomenclature.
Especially the interdisciplinary application fields of particle and particulate systems characterization
- from mining and construction industry, pharmaceutical and food industry, medicine and life sciences,
chemical industry, microelectronics and nanotechnology - need transparency and unambiguous
terminology. The development of international trade not only of measurement devices for particle
characterization, but also of process equipment for the production and treatment of particulate systems
need the comparability of quality and performance parameters as well as international health, safety
and environmental protection regulations.
The structuring and presentation rules applied to the terminological entries are based on a clause
structure, which represents the methods of sample preparation, measurement results presentation and
the analysis methods, starting with more general terms in each clause.
The clause headlines address "Terms related to" technical fields, which are understood as a kind of
domain with validity of the definitions limited to the indicated field.
The following particle properties are covered in the clauses given in brackets:
— particle size (3.1, 3.4 to 3.10, 3.12 to 3.15)
— particle shape (3.2, 3.8)
— particle number concentration (3.5, 3.9 and 3.12)
— pore size, pore volume (3.3)
— surface area (3.3, 3.10)
— electrical charge in aerosols (3.13)
— zeta potential in liquid dispersion (3.17)
— particle dispersion in liquids (3.16).
Data uncertainty related definitions are given in 3.1 and 3.11
v
INTERNATIONAL STANDARD ISO 26824:2022(E)
Particle characterization of particulate systems —
Vocabulary
1 Scope
This document defines terms that are relevant to the characterization of particles and particulate
systems. This document includes such fields as the representation of results of particle size analysis,
the descriptive and quantitative representation of particle shape and morphology, sample preparation,
specific surface area and porosity characterization and such measurement methods as sedimentation,
classification, acoustic methods, laser diffraction, dynamic light scattering, single particle light
interaction methods, differential electrical mobility analysis, image analysis and others in a size scale
from nanometre to millimetre.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 Terms related to representation of size and classification analysis data
3.1.1
particle
minute piece of matter with defined physical boundaries
Note 1 to entry: A physical boundary can also be described as an interface.
Note 2 to entry: A particle can move as a unit.
Note 3 to entry: This general particle definition applies to nano-objects (3.1.7).
[SOURCE: ISO 26824:2013, 1.1]
3.1.2
agglomerate
collection of weakly or medium strongly bound particles (3.1.1) where the resulting external surface
area is similar to the sum of the surface areas of the individual components
Note 1 to entry: The forces holding an agglomerate together are weak forces, for example van der Waals forces or
simple physical entanglement.
Note 2 to entry: Agglomerates are also termed secondary particles and the original source particles are termed
primary particles (3.1.4).
[SOURCE: ISO 26824:2013, 1.2]
3.1.3
aggregate
particle (3.1.1) comprising strongly bonded or fused particles where the resulting external surface area
is significantly smaller than the sum of surface areas of the individual components
Note 1 to entry: The forces holding an aggregate together are strong forces, for example covalent bonds, or those
resulting from sintering or complex physical entanglement or otherwise combined former primary particles
(3.1.4).
Note 2 to entry: Aggregates are also termed secondary particles and the original source particles are termed
primary particles (3.1.4).
[SOURCE: ISO 26824:2013, 1.3]
3.1.4
primary particle
original source particle (3.1.1) of agglomerates (3.1.2) or aggregates (3.1.3) or mixtures of the two
Note 1 to entry: Constituent particles (3.1.5) of agglomerates (3.1.2) or aggregates (3.1.3) at a certain actual state
can be primary particles, but often the constituents are aggregates.
Note 2 to entry: Agglomerates (3.1.2) and aggregates (3.1.3) are also termed secondary particles.
[SOURCE: ISO 26824:2013, 1.4]
3.1.5
constituent particle
identifiable, integral component of a larger particle (3.1.1)
Note 1 to entry: The constituent particle structures may be primary particles (3.1.4) or aggregates (3.1.3).
Note 2 to entry: See Figure 1.
Note 3 to entry: Constituent particles are considered as the smallest dispersible units of a large particle.
Key
1 agglomerate - constituent particles are identical to primary particles
2 aggregate with covalent bond - constituent particles are identical to primary particles
3 aggregate, produced from initially formed, primary particles (of approximetly 10 or more times smaller size
than the widths of the aggregate) which coalesce during the pyrogenic process and sinter into long chains (the
visible large circle-like parts never existed as isolated particles before)
4 example of an agglomerate, formed from aggregates (key 3), which are the constituent particles-
Figure 1 — Examples for agglomerates and aggregates of constituent particles and primary
particles (not identifiable as such in all cases)
[SOURCE: ISO/TS 80004-2:2015, 3.3, modified — Figure 1 has been added, Note 1 has been modified,
Note 2 and 3 have been added]
3.1.6
nanoscale
length range approximately from 1 nm to 100 nm
Note 1 to entry: Properties that are not extrapolations from larger sizes are predominantly exhibited in this
length range.
[SOURCE: ISO/TS 80004-1:2015, 2.1]
3.1.7
nano-object
discrete piece of material with one, two or three external dimensions in the nanoscale (3.1.6)
Note 1 to
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