ASTM B822-20

Standard Test Method for Particle Size Distribution of Metal Powders and Related Compounds by Light Scattering

SIGNIFICANCE AND USE
5.1 Reported particle size measurement is a function of both the actual particle dimension and shape factor as well as the particular physical or chemical properties being measured. Caution is required when comparing data from instruments operating on different physical or chemical parameters or with different particle size measurement ranges. Sample acquisition, handling, and preparation can also affect reported particle size results.  
5.1.1 It is important to recognize that the results obtained by this test method, or any other method for particle size determination using different physical principles, may disagree. The results are strongly influenced by the physical principles employed by each method of particle size analysis. The results of any particle sizing method should be used only in a relative sense; they should not be regarded as absolute when comparing results obtained by other methods.  
5.2 Light scattering theory has been available for many years for use in the determination of particle size. Several manufacturers of testing equipment now have units based on these principles. Although each type of testing equipment uses the same basic principles for light scattering as a function of particle size, different assumptions pertinent to application of the theory, and different models for converting light measurements to particle size, may lead to different results for each instrument. Therefore, the use of this test method cannot guarantee directly comparable results from different types of instruments.  
5.3 Knowledge of the particle size distribution of metal powders is useful in predicting the powder-processing behavior and ultimate performance of powder metallurgy parts. Particle size distribution is related closely to the flowability, moldability, compressibility, and die-filling characteristics of a powder, as well as to the final structure and properties of finished powder metallurgy (P/M) parts.  
5.4 This test method is useful to both suppli...
SCOPE
1.1 This test method covers the determination of the particle size distribution by light scattering, reported as volume percent, of particulate materials including metals and compounds.  
1.2 This test method applies to analyses with both aqueous and nonaqueous dispersions. In addition, analysis can be performed with a gaseous dispersion for materials that are hygroscopic or react with a liquid carrier.  
1.3 This test method is applicable to the measurement of particulate materials in the range of 0.4 to 2000 μm, or a subset of that range, as applicable to the particle size distribution being measured.  
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2020
• ICS: 13.300 - Protection against dangerous goods
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.02 - Base Metal Powders

Relations

• Refers: ASTM E1617-09(2024) - Standard Practice for Reporting Particle Size Characterization Data
• Effective Date: 01-Feb-2024
• Refers: ASTM E1617-09(2019) - Standard Practice for Reporting Particle Size Characterization Data
• Effective Date: 01-Apr-2019
• Refers: ASTM B243-18 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Oct-2018
• Refers: ASTM B243-16 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Jul-2016
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E1617-09(2014)e1 - Standard Practice for Reporting Particle Size Characterization Data
• Effective Date: 01-Apr-2014
• Refers: ASTM B243-13 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Nov-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM B243-12 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Jul-2012
• Refers: ASTM B243-11 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Nov-2011
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM B215-10 - Standard Practices for Sampling Metal Powders
• Effective Date: 01-Dec-2010
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM B821-10 - Standard Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size Analysis
• Effective Date: 01-Sep-2010

Overview

ASTM B822-20 is the internationally recognized standard for determining the particle size distribution of metal powders and related compounds using light scattering techniques, such as laser diffraction. Established by ASTM International, this standard method is essential for accurately characterizing the particle size distribution of particulate materials, with results typically reported as volume percent. ASTM B822-20 is applicable to a wide range of powdered metals and compounds and can accommodate analyses in both aqueous, nonaqueous, and gaseous dispersions, making it versatile for modern powder metallurgy and related industries.

Key Topics

• Light Scattering Theory: Utilizes theories such as Fraunhofer Diffraction and Mie Scattering to translate scattered light signals into particle size distributions, assuming particles as equivalent spheres.

• Measurement Range: Suitable for particles ranging from 0.4 to 2000 micrometers, accommodating most industrial and research needs for metal powders and related compounds.

• Sample Preparation: Emphasizes the importance of consistent sample acquisition, handling, and preparation. The procedures minimize errors related to agglomeration, contaminants, or improper dispersion, ensuring reliable results.

• Instrument Variation: Recognizes that different models and technologies of particle size analyzers may yield varying results due to differing application of light scattering principles. Data should be interpreted relatively rather than absolutely, especially when comparing across different methods or instruments.

• Reporting Requirements: Specifies key data to report, including instrument details, sample preparation techniques, refractive indices, volume mean diameter, and detailed size distribution curves.

• Precision and Bias: Provides guidelines for repeatability and outlines the importance of interlaboratory studies to establish consistent precision. Reproducibility can be affected by variations in sample dispersion techniques.

• Interferences and Limitations: Identifies potential sources of measurement errors, such as air bubbles, contaminants, and improper sample loading, stressing the need for careful procedural control.

Applications

ASTM B822-20 is widely applied in industries and research areas where particle size distribution impacts processability and final product performance. Key applications include:

• Powder Metallurgy: Enables manufacturers to predict powder flowability, moldability, compressibility, and die-filling characteristics, ensuring optimal production of metal parts.
• Quality Control: Used by both suppliers and users of powders for product specification development, lot-to-lot comparison, acceptance testing, and process optimization.
• Research and Development: Facilitates material development and research by providing precise particle size data vital to innovation in metallic compounds and advanced materials.
• Conformance and Regulatory Testing: Assures compliance with internal and external standards for particle size in powdered materials.

Related Standards

ASTM B822-20 references and aligns with several key standards in the field of metal powder analysis and particle size measurement:

• ASTM B215 - Practices for Sampling Metal Powders
• ASTM B243 - Terminology of Powder Metallurgy
• ASTM B821 - Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size Analysis
• ASTM E177 - Practice for Use of the Terms Precision and Bias
• ASTM E691 - Practice for Interlaboratory Studies
• ASTM E1617 - Practice for Reporting Particle Size Characterization Data
• ISO 13320-1 - Particle Size Analysis-Laser Diffraction Methods-General Principles

By adhering to ASTM B822-20, organizations ensure that their methods for determining the particle size distribution of metal powders are robust, scientifically sound, and internationally recognized. This supports product development, regulatory compliance, and consistent quality in critical industrial applications.

Keywords: ASTM B822-20, particle size distribution, metal powders, light scattering, laser diffraction, powder metallurgy, quality control, powder analysis, particle size measurement, industrial standards.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: B822 − 20
Standard Test Method for
Particle Size Distribution of Metal Powders and Related
Compounds by Light Scattering
This standard is issued under the fixed designation B822; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* B243 Terminology of Powder Metallurgy
B821 Guide for Liquid Dispersion of Metal Powders and
1.1 Thistestmethodcoversthedeterminationoftheparticle
Related Compounds for Particle Size Analysis
size distribution by light scattering, reported as volume
E177 Practice for Use of the Terms Precision and Bias in
percent, of particulate materials including metals and com-
ASTM Test Methods
pounds.
E691 Practice for Conducting an Interlaboratory Study to
1.2 This test method applies to analyses with both aqueous
Determine the Precision of a Test Method
and nonaqueous dispersions. In addition, analysis can be
E1617 Practice for Reporting Particle Size Characterization
performed with a gaseous dispersion for materials that are
Data
hygroscopic or react with a liquid carrier.
2.2 ISO Standard:
1.3 This test method is applicable to the measurement of ISO13320-1 Particle Size Analysis—Laser Diffraction
Methods—Part 1: General Principles
particulate materials in the range of 0.4 to 2000 µm, or a subset
of that range, as applicable to the particle size distribution
3. Terminology
being measured.
3.1 Definitions—Definitions of powder metallurgy terms
1.4 Units—The values stated in SI units are to be regarded
can be found in Terminology B243.
as standard. No other units of measurement are included in this
3.2 Definitions of Terms Specific to This Standard:
standard.
3.2.1 background, n—extraneous scattering of light by ele-
1.5 This standard does not purport to address all of the
ments other than the particles to be measured; includes
safety concerns, if any, associated with its use. It is the
scattering by contamination in the measurement path.
responsibility of the user of this standard to establish appro-
3.2.2 Fraunhofer Diffraction, n—the optical theory that
priate safety, health, and environmental practices and deter-
describes the low-angle scattering of light by particles that are
mine the applicability of regulatory limitations prior to use.
large compared to the wavelength of the incident light.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard- 3.2.3 Mie Scattering, n—the complex electromagnetic
theory that describes the scattering of light by spherical
ization established in the Decision on Principles for the
particles.
Development of International Standards, Guides and Recom-
3.2.3.1 Discussion—It is usually applied to particles with
mendations issued by the World Trade Organization Technical
diameters that are close to the wavelength of the incident light.
Barriers to Trade (TBT) Committee.
The real and imaginary indices of light refraction of the
2. Referenced Documents particles are needed.
3.2.4 multiple scattering, n—the rescattering of light by a
2.1 ASTM Standards:
particle in the path of light scattered by another particle.
B215 Practices for Sampling Metal Powders
3.2.4.1 Discussion—This usually occurs in heavy concen-
trations of a particle dispersion.
This test method is under the jurisdiction of ASTM Committee B09 on Metal
4. Summary of Test Method
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.02 on Base Metal Powders.
4.1 Aprepared sample of particulate material is dispersed in
Current edition approved Oct. 1, 2020. Published October 2020. Originally
water, or a compatible organic liquid, and circulated through
approved in 1992. Last previous edition approved in 2017 as B822 – 17. DOI:
10.1520/B0822-20.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM 4th Floor, New York, NY 10036, http://www.ansi.org.
Standards volume information, refer to the standard’s Document Summary page on Muly, E. C., Frock, H. N., “Industrial Particle Size Measurement Using Light
the ASTM website. Scattering,” Optical Engineering, Vol 19, No. 6, 1980, pp. 861–869.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B822 − 20
the path of a light beam or some other suitable light source.A 6. Interferences
dry sample may be aspirated through the light in a carrier gas.
6.1 Air bubbles entrained in the circulating fluid will scatter
The particles pass through the light beam and scatter it.
light and then be reported as particles. Circulating fluids may
Photodetectorarrayscollectthescatteredlightthatisconverted
not require degassing, but they should be bubble-free upon
to electrical signals, which are then analyzed in a micropro-
visual inspection.
cessor. The signal is converted to a size distribution using
6.2 Contaminants, such as nonaqueous solvents, oil, or
Fraunhofer Diffraction or Mie Scattering, or a combination of
other organic coatings on the sample, may emulsify in an
both. Scattering information is analyzed assuming a spherical
aqueouscarrier,scatterlight,andthusbereportedaspartofthe
model. Calculated particle sizes are therefore presented as
particle size distribution. Samples containing such contami-
equivalent spherical diameters.Additional information pertain-
nants may be analyzed in a nonaqueous carrier solvent to
ing to the general principles of particle size distribution
dissolve the contaminant, or they may be washed free of the
analysis by light scattering can be found in ISO Standard
contaminant with a compatible aqueous solvent.
13320-1.
6.3 The presence of oil, water, or foreign substances in a
gaseous dispersion will cause clogging or agglomeration or
5. Significance and Use
will bias the particle size results. The gas supplied should be
5.1 Reportedparticlesizemeasurementisafunctionofboth
free of these substances.
the actual particle dimension and shape factor as well as the
6.4 Reagglomeration or settling of particulates during
particular physical or chemical properties being measured.
analysis will cause erroneous results. Dispersions shall be
Caution is required when comparing data from instruments
prepared in accordance with Guide B821, and a stable disper-
operating on different physical or chemical parameters or with
sion shall be maintained throughout the analysis.
different particle sizemeasurementranges.Sampleacquisition,
handling, and preparation can also affect reported particle size
6.5 Insufficient sample loading may cause electrical noise
results.
interference and poor data repeatability. Excessive sample
5.1.1 Itisimportanttorecognizethattheresultsobtainedby loading may cause excessive light attenuation and multiple
this test method, or any other method for particle size deter- scattering, resulting in erroneous particle size distributions.
mination using different physical principles, may disagree.The
7. Apparatus
results are strongly influenced by the physical principles
employed by each method of particle size analysis. The results
7.1 Particle Size Analyzer, based on Fraunhofer Diffraction
of any particle sizing method should be used only in a relative
or Mie Scattering, or a combination of both light scattering
sense;theyshouldnotberegardedasabsolutewhencomparing
analysis techniques. Care must be taken to ensure that the
results obtained by other methods.
analyzer system or subsystem is optimum for the size range of
the powder being tested.
5.2 Light scattering theory has been available for many
years for use in the determination of particle size. Several
7.2 Liquid or Gaseous Sample Handling System.
manufacturers of testing equipment now have units based on
these principles.Although each type of testing equipment uses 8. Reagents and Materials
the same basic principles for light scattering as a function of
8.1 Purity of Reagents—Reagent grade chemicals shall be
particle size, different assumptions pertinent to application of
used in all tests. Unless otherwise indicated, it is intended that
the theory, and different models for converting light measure-
all reagents shall conform to the specifications of the Commit-
ments to particle size, may lead to different results for each
tee onAnalytical Reagents of theAmerican Chemical Society.
instrument. Therefore, the use of this test method cannot
Other grades may be used, provided it is first ascertained that
guarantee directly comparable results from different types of
the reagent is of sufficiently high purity to permit its use
instruments.
without lessening the accuracy of the determination.
5.3 Knowledge of the particle size distribution of metal
8.2 Appropriate Application-Specific Carrier, as determined
powdersisusefulinpredictingthepowder-processingbehavior
by Guide B821. The carrier shall meet the following condi-
and ultimate performance of powder metallurgy parts. Particle
tions:
size distribution is related closely to the flowability,
8.2.1 It shall be chemically compatible with the construc-
moldability, compressibility, and die-filling characteristics of a
tion material of the sample delivery system,
powder, as well as to the final structure and properties of
8.2.2 It shall not cause dissolution of the particles, and
finished powder metallurgy (P/M) parts.
8.2.3 It shall be sufficiently clean and non-absorbing to
achieve acceptable background levels.
5.4 This test method is useful to both suppliers and users of
powders in determining the particle size distributions for
product specifications, manufacturing control, development,
Reagent Chemicals, American Chemical Society Specifications, American
and research.
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
5.5 This test method may be used to obtain data for
Chemicals, BDH Ltd., Poole, Dorset, U.K., and
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B822 − 17 B822 − 20
Standard Test Method for
Particle Size Distribution of Metal Powders and Related
Compounds by Light Scattering
This standard is issued under the fixed designation B822; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This test method covers the determination of the particle size distribution by light scattering, reported as volume percent, of
particulate materials including metals and compounds.
1.2 This test method applies to analyses with both aqueous and nonaqueous dispersions. In addition, analysis can be performed
with a gaseous dispersion for materials that are hygroscopic or react with a liquid carrier.
1.3 This test method is applicable to the measurement of particulate materials in the range of 0.4 to 2000 μm, or a subset of that
range, as applicable to the particle size distribution being measured.
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this
standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
B215 Practices for Sampling Metal Powders
B243 Terminology of Powder Metallurgy
B821 Guide for Liquid Dispersion of Metal Powders and Related Compounds for Particle Size Analysis
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1617 Practice for Reporting Particle Size Characterization Data
2.2 ISO Standard:
ISO13320-1 Particle Size Analysis—Laser Diffraction Methods—Part 1: General Principles
This test method is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.02
on Base Metal Powders.
Current edition approved April 1, 2017Oct. 1, 2020. Published April 2017October 2020. Originally published asapproved in B822 – 92.1992. Last previous edition
approved in 20102017 as B822 –10. – 17. DOI: 10.1520/B0822-17.10.1520/B0822-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B822 − 20
3. Terminology
3.1 Definitions—Definitions of powder metallurgy terms can be found in Terminology B243.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 background—background, n—extraneous scattering of light by elements other than the particles to be measured; includes
scattering by contamination in the measurement path.
3.2.2 Fraunhofer Diffraction—Diffraction, n—the optical theory that describes the low-angle scattering of light by particles that
are large compared to the wavelength of the incident light.
3.2.3 Mie Scattering—Scattering, n—the complex electromagnetic theory that describes the scattering of light by spherical
particles. It is usually applied to particles with diameters that are close to the wavelength of the incident light. The real and
imaginary indices of light refraction of the particles are needed.
3.2.3.1 Discussion—
It is usually applied to particles with diameters that are close to the wavelength of the incident light. The real and imaginary indices
of light refraction of the particles are needed.
3.2.4 multiple scattering—scattering, n—the rescattering of light by a particle in the path of light scattered by another particle. This
usually occurs in heavy concentrations of a particle dispersion.
3.2.4.1 Discussion—
This usually occurs in heavy concentrations of a particle dispersion.
4. Summary of Test Method
4.1 A prepared sample of particulate material is dispersed in water, or a compatible organic liquid, and circulated through the path
of a light beam or some other suitable light source. A dry sample may be aspirated through the light in a carrier gas. The particles
pass through the light beam and scatter it. Photodetector arrays collect the scattered light that is converted to electrical signals,
which are then analyzed in a microprocessor. The signal is converted to a size distribution using Fraunhofer Diffraction or Mie
Scattering, or a combination of both. Scattering information is analyzed assuming a spherical model. Calculated particle sizes are
therefore presented as equivalent spherical diameters. Additional information pertaining to the general principles of particle size
distribution analysis by light scattering can be found in ISO Standard 13320-1.
5. Significance and Use
5.1 Reported particle size measurement is a function of both the actual particle dimension and shape factor as well as the particular
physical or chemical properties being measured. Caution is required when comparing data from instruments operating on different
physical or chemical parameters or with different particle size measurement ranges. Sample acquisition, handling, and preparation
can also affect reported particle size results.
5.1.1 It is important to recognize that the results obtained by this test method, or any other method for particle size determination
using different physical principles, may disagree. The results are strongly influenced by the physical principles employed by each
method of particle size analysis. The results of any particle sizing method should be used only in a relative sense; they should not
be regarded as absolute when comparing results obtained by other methods.
5.2 Light scattering theory has been available for many years for use in the determination of particle size. Several manufacturers
of testing equipment now have units based on these principles. Although each type of testing equipment uses the same basic
principles for light scattering as a function of particle size, different assumptions pertinent to application of the theory, and different
models for converting light measurements to particle size, may lead to different results for each instrument. Therefore, the use of
this test method cannot guarantee directly comparable results from different types of instruments.
5.3 Knowledge of the particle size distribution of metal powders is useful in predicting the powder-processing behavior and
Muly, E. C., Frock, H. N., “Industrial Particle Size Measurement Using Light Scattering,” Optical Engineering, Vol 19, NoNo. 6, 1980, pp. 861–869.
B822 − 20
ultimate performance of powder metallurgy parts. Particle size distribution is related closely to the flowability, moldability,
compressibility, and die-filling characteristics of a powder, as well as to the final structure and properties of finished powder
metallurgy (P/M) parts.
5.4 This test method is useful to both suppliers and users of powders in determining the particle size distributions for product
specifications, manufacturing control, development, and research.
5.5 This test method may be used to obtain data for comparison between lots of the same material or for establishing conformance,
as in acceptance testing.
6. Interferences
6.1 Air bubbles entrained in the circulating fluid will scatter light and then be reported as particles. Circulating fluids may not
require degassing, but they should be bubble-free upon visual inspection.
6.2 Contaminants, such as nonaqueous solvents, oil, or other organic coatings on the sample, may emulsify in an aqueous carrier,
scatter light, and thus be reported as part of the particle size distribution. Samples containing such contaminants may be analyzed
in a nonaqueous carrier solvent to dissolve the contaminant, or they may be washed free of the contaminant with a compatible
aqueous solvent.
6.3 The presence of oil, water, or foreign substances in a gaseous dispersion will cause clogging or agglomeration or will bias the
particle size results. The gas supplied should be free of these substances.
6.4 Reagglomeration or settling of particulates during analysis will cause erroneous results. Dispersions shall be prepared in
accordance with Guide B821, and a stable dispersion shall be maintained throughout the analysis.
6.5 Insufficient sample loading may cause electrical noise interference and poor data repeatability. Excessive sample loading may
cause excessive light attenuation and multiple scattering, resulting in erroneous particle size distributions.
7. Apparatus
7.1 Particle Size Analyzer, based on Fraunhofer Diffraction or Mie Scattering, or a combination of both light scattering analysis
techniques. Care must be taken to ensure that the analyzer system or subsystem is optimum for the size range of the powder being
tested.
7.2 Liquid or Gaseous Sample Handling System.
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society. Other
grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening
the accuracy of the determination.
8.2 Appropriate Application-Specific Carrier, as determined by Guide B821. The carrier shall meet the following conditions:
8.2.1 It shall be chemically compatible with the construction material of the sample delivery system,
8.2.2 It shall not cause dissolution of the particles, and
8.2.3 It shall be sufficiently clean and non-absorbing to achieve acceptable background levels.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. P
...