EN ISO/ASTM 52928:2024

Additive manufacturing of metals - Feedstock materials - Powder life cycle management (ISO/ASTM 52928:2024)

This document specifies requirements and describes aspects for the lifecycle management of metal feedstock materials for powder based additive manufacturing processes. These aspects include but are not limited to:
—     powder properties;
—     powder lifecycle;
—     test methods;
—     powder quality assurance.
This document supplements ISO/ASTM 52907, which primarily focuses on requirements for virgin powder. This document covers on powder life cycle management, and therefore focuses on control of virgin and used powders.
This document can be used by manufacturers of metal powders, purchasers of powder feedstock for additive manufacturing, those responsible for the quality assurance of additively manufactured parts and suppliers of measurement and testing equipment for characterizing metal powders for use in powder-based additive manufacturing processes.

Additive Fertigung von Metallen - Ausgangsmaterialien - Steuerung des Lebenszyklus von Pulvern (ISO/ASTM 52928:2024)

Dieses Dokument legt Anforderungen fest und beschreibt Aspekte, die die Steuerung des Lebenszyklus von Metall-Ausgangsmaterialien für pulverbasierte additive Fertigungsprozesse betreffen. Diese Aspekte umfassen unter anderem:
   Pulvereigenschaften;
   Pulver-Lebenszyklus;
   Prüfverfahren;
   Pulver-Qualitätssicherung.
Dieses Dokument ergänzt ISO/ASTM 52907, das sich hauptsächlich mit den Anforderungen für neues Pulver befasst. Dieses Dokument deckt die Steuerung des Lebenszyklus von Pulver ab und beschäftigt sich daher mit der Kontrolle sowohl von neuen als auch gebrauchten/wiederverwendeten Pulvern.
Dieses Dokument kann von Herstellern von Metallpulvern, Einkäufern von Pulver-Ausgangsmaterial für die additive Fertigung, Verantwortlichen für die Qualitätssicherung additiv gefertigter Teile und Lieferanten von Mess- und Prüfeinrichtungen für die Charakterisierung von Metallpulvern, für den Gebrauch in pulverbasierten additiven Fertigungsprozessen verwendet werden.
Dieses Dokument legt Anforderungen fest und beschreibt Aspekte, die das Lebensdauermanagement von Metall-Ausgangsmaterialien für pulverbasierte additive Fertigungsprozesse betreffen. Diese Aspekte umfassen unter anderem:
   Pulvereigenschaften;
   Pulver-Lebensdauer;
   Prüfverfahren;
   Pulver-Qualitätssicherung.
Dieses Dokument ergänzt ISO/ASTM 52907, bei dem es hauptsächlich um Anforderungen für neues Pulver geht. Dieses Dokument deckt das Lebensdauermanagement von Pulver ab und beschäftigt sich daher mit der Kontrolle von neuen und gebrauchten Pulvern.
Dieses Dokument kann von Herstellern von Metallpulvern, Käufern von Pulver-Ausgangsmaterial für die additive Fertigung, Verantwortlichen für die Qualitätssicherung additiv gefertigter Teile und Lieferanten von Mess- und Prüfeinrichtungen für die Charakterisierung von Metallpulvern für den Gebrauch in pulverbasierten additiven Fertigungsprozessen verwendet werden.

Fabrication additive de métaux - Matières premières - Gestion du cycle de vie de la poudre (ISO/ASTM 52928:2024)

Le présent document spécifie les exigences et décrit les aspects concernant la gestion du cycle de vie des matières premières métalliques utilisées pour les procédés de fabrication additive à base de poudres. Ces aspects incluent, sans toutefois s’y limiter:
—     les propriétés de la poudre;
—     le cycle de vie de la poudre;
—     les méthodes d’essai;
—     l’assurance qualité de la poudre.
Le présent document complète l’ISO/ASTM 52907, qui se concentre principalement sur les exigences pour la poudre vierge. Le présent document couvre la gestion du cycle de vie de la poudre et se concentre ainsi sur le contrôle des poudres vierges et utilisées.
Le présent document peut être utilisé par les fabricants de poudres métalliques, les acheteurs de matières premières en poudre pour la fabrication additive, les personnes responsables de l’assurance qualité des pièces fabriquées additivement et les fournisseurs d’équipements de mesure et d’essai pour caractériser les poudres métalliques destinées à être utilisées dans des procédés de fabrication additive à base de poudres.

Dodajalna izdelava kovinskih izdelkov - Surovine - Obvladovanje življenjskega cikla prahu (ISO/ASTM 52928:2024)

Ta dokument določa zahteve in opisuje vidike za obvladovanje življenjskega cikla kovinskih surovin za procese dodajalne izdelave na osnovi prahu. Ti vidiki med drugim vključujejo:
– lastnosti prahu;
– življenjski cikel prahu;
– preskusne metode;
– zagotavljanje kakovosti prahu.
Ta dokument dopolnjuje standard ISO/ASTM 52907, ki se osredotoča predvsem na zahteve za neuporabljen prah.
Ta dokument obravnava obvladovanje življenjskega cikla prahu ter se tako osredotoča na nadzor neuporabljenega in uporabljenega prahu.
Ta dokument lahko uporabljajo proizvajalci kovinskega prahu, kupci praškastih surovin za dodajalno izdelavo, odgovorne osebe za zagotavljanje kakovosti dodajalno izdelanih delov ter dobavitelji merilne in preskusne opreme za karakterizacijo kovinskega prahu za uporabo v postopkih dodajalne izdelave na osnovi prahu.

General Information

• Status: Published
• Publication Date: 28-May-2024
• ICS: 25.030 - Additive manufacturing
• Technical Committee: CEN/TC 438 - Additive Manufacturing
• Drafting Committee: CEN/TC 438 - Additive Manufacturing
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 29-May-2024
• Due Date: 25-Oct-2023
• Completion Date: 29-May-2024
• Ref Project: SIST EN ISO/ASTM 52928:2025 - Additive manufacturing of metals - Feedstock materials - Powder life cycle management (ISO/ASTM 52928:2024)

Standards Content (Sample)

SLOVENSKI STANDARD
01-marec-2025
Dodajalna izdelava kovinskih izdelkov - Surovine - Obvladovanje življenjskega
cikla prahu (ISO/ASTM 52928:2024)
Additive manufacturing of metals - Feedstock materials - Powder life cycle management
(ISO/ASTM 52928:2024)
Additive Fertigung von Metallen - Ausgangsmaterialien - Steuerung des Lebenszyklus
von Pulvern (ISO/ASTM 52928:2024)
Fabrication additive de métaux - Matières premières - Gestion du cycle de vie de la
poudre (ISO/ASTM 52928:2024)
Ta slovenski standard je istoveten z: EN ISO/ASTM 52928:2024
ICS:
25.030 3D-tiskanje Additive manufacturing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO/ASTM 52928
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2024
EUROPÄISCHE NORM
ICS 25.030
English Version
Additive manufacturing of metals - Feedstock materials -
Powder life cycle management (ISO/ASTM 52928:2024)
Fabrication additive de métaux - Matières premières - Additive Fertigung von Metallen - Ausgangsmaterialien
Gestion du cycle de vie de la poudre (ISO/ASTM - Steuerung des Lebenszyklus von Pulvern (ISO/ASTM
52928:2024) 52928:2024)
This European Standard was approved by CEN on 17 May 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO/ASTM 52928:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO/ASTM 52928:2024) has been prepared by Technical Committee ISO/TC 261
"Additive manufacturing" in collaboration with Technical Committee CEN/TC 438 “Additive
Manufacturing” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2024, and conflicting national standards
shall be withdrawn at the latest by November 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/ASTM 52928:2024 has been approved by CEN as EN ISO/ASTM 52928:2024 without
any modification.
International
Standard
ISO/ASTM 52928
First edition
Additive manufacturing of metal —
2024-05
Feedstock materials — Powder life
cycle management
Fabrication additive de métaux — Matières premières — Gestion
du cycle de vie de la poudre
Reference number
ISO/ASTM 52928:2024(en) © ISO/ASTM International 2024

ISO/ASTM 52928:2024(en)
© ISO/ASTM International 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester. In the United States, such requests should be sent to ASTM International.
ISO copyright office ASTM International
CP 401 • Ch. de Blandonnet 8 100 Barr Harbor Drive, PO Box C700
CH-1214 Vernier, Geneva West Conshohocken, PA 19428-2959, USA
Phone: [phone] Phone: [phone]
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Email: [e-mail] Email: [e-mail]
Website: www.iso.org Website: www.astm.org
Published in Switzerland
© ISO/ASTM International 2024 – All rights reserved
ii
ISO/ASTM 52928:2024(en)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviations . 2
5 Powder properties . 3
5.1 General .3
5.2 Particle size distribution .3
5.2.1 General .3
5.2.2 Dynamic image analysis .4
5.2.3 Laser diffraction and light scattering .4
5.2.4 Dry sieving .5
5.2.5 Light or scanning electron microscopy (SEM) images .5
5.3 Chemical composition .5
5.3.1 General .5
5.3.2 Combustion methods.6
5.3.3 Flame AAS .7
5.3.4 X-ray fluorescence spectroscopy (XRF) .7
5.3.5 Inductively coupled plasma optical emission spectrometry (ICP-OES) .7
5.3.6 Energy-dispersive X-ray spectroscopy (EDX) .7
5.4 Characteristic densities .8
5.4.1 General .8
5.4.2 Apparent density .8
5.4.3 Tap density .8
5.4.4 Skeletal (true) density .8
5.4.5 Packing behaviour .8
5.5 Determination of powder density .9
5.5.1 Determination of the closed porosity of particles via indirect methods .9
5.5.2 Gas pycnometry.9
5.5.3 Metallographic section with porosity analysis .9
5.6 Shape and morphology .9
5.6.1 General .9
5.6.2 Image analysis .11
5.6.3 Scanning electron microscopy (SEM) images .11
5.6.4 Light microscopy images . 12
5.6.5 Determination of specific surface area . 12
5.7 Flowability . 12
5.7.1 General . 12
5.7.2 Determination of flow rate . 13
5.7.3 Measuring the angle of repose . 13
5.7.4 Ring shear test method . 13
5.7.5 Rotating drum with dynamic image analysis . 13
5.7.6 Powder rotational rheometer . 13
5.7.7 Hausner ratio (ratio of tapped to bulk density) . 13
5.8 Contamination .14
5.8.1 Moisture content .14
5.8.2 Impurities . 15
5.8.3 O/H content . 15
5.8.4 N content. 15
5.9 Absorption rate of the powder . 15
5.9.1 General . 15
5.9.2 Diffuse reflectance infrared Fourier transform (DRIFTS). 15

© ISO/ASTM International 2024 – All rights reserved
iii
ISO/ASTM 52928:2024(en)
6 Powder life cycle . .16
6.1 Batch requirement .16
6.1.1 General .16
6.1.2 Specification .16
6.1.3 Batch .16
6.1.4 Blend . .16
6.1.5 Powder mix .16
6.1.6 Combine .16
6.1.7 Reuse metric . .16
6.2 Traceability .17
6.2.1 General .17
6.2.2 Event history .17
6.2.3 Powder state . . .17
6.2.4 Labelling .17
6.3 Handling .18
6.3.1 General .18
6.3.2 Storage .18
6.3.3 Transfer .18
6.3.4 Repacking .19
6.4 Recycling/reuse of feedstock .19
6.5 Disposal . . .19
7 Powder quality assurance . .20
7.1 Documentation requirements . 20
7.2 Certificate of analysis (CoA) . 20
7.3 Sampling . 20
7.3.1 General remarks . 20
7.3.2 Characterization of virgin powder and powder blends .21
7.3.3 Characterization of used powder . 22
7.4 Powder analysis test methods . 22
7.5 Monitoring and control of the environment . 22
7.6 Test frequency . 23
Bibliography .24

© ISO/ASTM International 2024 – All rights reserved
iv
ISO/ASTM 52928:2024(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available
at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights. Any
trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 261, Additive manufacturing, in cooperation
with ASTM Committee F42, Additive Manufacturing Technologies, on the basis of a partnership agreement
between ISO and ASTM International with the aim to create a common set of ISO/ASTM standards on
additive manufacturing, and in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 438, Additive manufacturing, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
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.

© ISO/ASTM International 2024 – All rights reserved
v
ISO/ASTM 52928:2024(en)
Introduction
Metal powders represent the feedstock for numerous additive manufacturing processes. Specifications
and quality of metal powder feedstock are directly related to the quality and performance of components
fabricated by additive manufacturing (AM).
During their usage in additive manufacturing processes as well as during storage and handling, powders
can be subject to various quality-relevant influencing factors.
These may include:
— cross-contamination and impurities;
— changes in particle size distribution;
— reactions with ambient gases;
— changes in moisture content;
— changes in flow properties;
— changes of particle morphology;
— absorption of welding fumes and spatters;
— changes in chemical composition due to selective evaporation of individual alloying elements.
Quality assurance of the powder materials over the entire service life from receiving, over storage and
handling to reuse and disposal is therefore decisive for qualified additive manufacturing processes in any
relevant industry.
This document aims to raise awareness of powder quality issues and to describe measures and procedures
for quality assurance, batch identification and traceability of powder materials. The proposed measures
are derived from best practices in the processing industry with a main emphasis on how frequently and at
which stages of the process chain to document certain properties.
NOTE As the metal powder/feedstock is the main input of the AM process, its quality, both incoming and in
service, impacts the quality of the AM output. However, the control over the quality of the input is one possible strategy
to ensure the quality of the process output. Alternatively, the supplier/manufacturer is allowed to certify the quality
of the AM components through
a) validation and verification of the AM process, as per internal procedures, and
b) inspection of the CTQs (critical to quality) of the AM components, as per customer agreement.

© ISO/ASTM International 2024 – All rights reserved
vi
International Standard ISO/ASTM 52928:2024(en)
Additive manufacturing of metal — Feedstock materials —
Powder life cycle management
1 Scope
This document specifies requirements and describes aspects for the lifecycle management of metal feedstock
materials for powder based additive manufacturing processes. These aspects include but are not limited to:
— powder properties;
— powder lifecycle;
— test methods;
— powder quality assurance.
This document supplements ISO/ASTM 52907, which primarily focuses on requirements for virgin powder.
This document covers on powder life cycle management, and therefore focuses on control of virgin and used
powders.
This document can be used by manufacturers of metal powders, purchasers of powder feedstock for additive
manufacturing, those responsible for the quality assurance of additively manufactured parts and suppliers
of measurement and testing equipment for characterizing metal powders for use in powder-based additive
manufacturing processes.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 12154, Determination of density by volumetric displacement — Skeleton density by gas pycnometry
ISO/ASTM 52900, Additive manufacturing — General principles — Fundamentals and vocabulary
ISO/ASTM 52907, Additive manufacturing — Feedstock materials — Methods to characterize metal powders
ASTM B923, Standard Test Method for Metal Powder Skeletal Density by Helium or Nitrogen Pycnometry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/ASTM 52900 and the following apply.
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
split
action of physically or systematically splitting a batch into one or more smaller volumes of powder
Note 1 to entry: It is possible that such action is taken in order to differentiate between volumes of powder used for
individual machines but which originate from a single large batch.

© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
3.2
sub-batch
quantity of powder which has been split (3.1) from a larger batch
Note 1 to entry: A sub-batch can also be designated as a new single batch (e.g. with a sub-name or suffix).
3.3
combine
merge two or more powder batches of the same nominal specification in the same container or AM system
without active blending
EXAMPLE An AM machine feedstock hopper is topped up with powder whilst an existing volume of powder
remains in the hopper.
3.4
reuse metric
quantitative measure of the exposure or use of a powder batch in an AM process
Note 1 to entry: This may be expressed iteratively, for example a number of builds or exposures, or with a continuous
scale such as total laser exposure time (laser-on time) or total incident energy.
4 Symbols and abbreviations
The following symbols and abbreviations are used throughout this document.
Table 1 — Symbols
Symbol Designation Unit
D 10 % quantile of particle size based on the sample volume μm
V10
D 50 % quantile of particle size based on the sample volume µm
V50
D 90 % quantile of particle size based on the sample volume µm
V90
H Hausner ratio —
I Inter-particle porosity —
e
V bulk volume inside the drum ml
drum
V tapped volume ml
tap
ρ bulk density g/ml
b
ρ tapped density g/ml
tap
© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
Table 2 — Abbreviations
Abbreviation Designation
AAS Atom absorption spectrometry
CoA Certificate of analysis
DRIFTS Diffuse reflectance infrared Fourier transform spectroscopy
EDX Energy-dispersive X-ray spectroscopy
ELI Extra low interstitial
ETAAS Electrothermal atom absorption spectrometry
FAAS Flame atom absorption spectrometry
GFAAS Graphite furnace atom absorption spectrometry
ICP-OES Inductively coupled plasma optical emission spectrometry
IoT Internet of things
ppm Parts per million
SEM Scanning electron microscopy
XFA X-ray fluorescence analysis
XRF X-ray fluorescence spectroscopy
5 Powder properties
5.1 General
Powder properties are critical to the manufacturing process and the quality of the formed material in the
final product. To help with the repeatability of the process and the quality and consistency of the products
produced, certain powder properties require measurement and monitoring on receipt and re-use of the
feedstock.
The following subclauses provide further information on these properties and the effects they have on the
AM process and final product. Measurement techniques for each property are provided in each subclause.
For the process-influencing parameters discussed in the following subclauses, properties shall be
determined by examining a representative sample of the powder, ensuring homogeneity when split. Refer to
7.3 for detailed information on sampling methods.
Procedures should be included for equipment cleanliness prior to sampling to prevent cross contamination
of powder.
5.2 Particle size distribution
5.2.1 General
The particle size distribution of a powder is a set of characteristic values or a mathematical function that
describes the relative amount of particles (typically by mass or number) of a certain size class or category.
During processing in additive manufacturing machines, the particle size distribution typically shifts to
higher (coarser) values as small particles tend to be carried away by the inert gas flow and collected in ultra-
fine filters. Particles melt together to form larger particles, and reactions with ambient gases lead to surface
layers on the particles, which increases their volume and mass.
The processing behaviour (e.g. flowability, packing behaviour) of a certain powder is particularly influenced
by the width, the median and the lower and upper limits of the particle size distribution. Engineered powder
lots can contain unimodal, bi-modal or multi-modal distributions (see Figure 1) with significant changes
based on deviations from as-designed particle size distributions.

© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
a)  Uni-modal b)  Bi-modal
Key
X particle size, in μm
Y relative proportion of particles, in %
Figure 1 — Particle size distribution charts
Particle size distribution has a direct effect on the processability of the powder. A shift in distribution which
increases the proportion of fine or coarse particles has an impact on the flow characteristics and coating
capacity of powder, for example in a beam melting machine. Particle size distribution also affects the density
of the powder bed and thus its energy absorption and distribution behaviour.
The following methods may be used to determine the particle size distribution in the metal powder. The
latter methods mostly require greater analytical effort.
NOTE The results obtained from the different methods are in general not directly comparable.
5.2.2 Dynamic image analysis
Dynamic image analysis, in accordance with ISO 13322-2, is a method of characterizing particles by optically
analysing their shadow projections. By capturing an image of the particle, it is possible to calculate various
particle size and shape parameters such as diameter, maximum length, circularity, or minimum width.
During analysis, each separate measurement is assigned to a measuring class according to its size. The
upper and lower limit of the measuring range are determined by the camera resolution and magnification.
NOTE 1 The results of dynamic image analysis largely depend on the measurement parameters and settings of the
evaluation algorithms. Consequently, significantly different results can be obtained from measurement systems made
by different manufacturers.
It shall be observed that the results may be presented by volume or number.
NOTE 2 With these types of analytical systems, it is often possible to analyse particle size distribution and particle
morphology simultaneously, allowing correlations to be made between morphology and particle size.
5.2.3 Laser diffraction and light scattering
Laser diffraction and light scattering in accordance with ISO 13320 or ASTM B822 calculates the particle
size by measuring the light scatter produced (angle, intensity) as a laser beam passes through a dispersed
powder sample. With laser diffraction, it shall be observed that the particle size distribution can be reported
as volume- or number-based data. This method is used for particle sizes ranging from 0,1 μm to 3 mm and
is highly suitable for comparative measurements. With irregularly shaped powder particles, for example,

© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
the particle size distribution obtained corresponds to the light scattering behaviour of a volume of spherical
powder. Consequently, the results can differ from those obtained by dry sieving or sedimentation.
NOTE The results of laser diffraction largely depend on the measurement parameters and settings of the
evaluation algorithms. Consequently, significantly different results can be obtained from measurement systems made
by different manufacturers.
5.2.4 Dry sieving
Dry sieving in accordance with ISO 2591-1, ISO 4497 or ASTM B214 is only suitable for dry powders that
contain no binders or auxiliary materials. ISO 4497 does not recommend the use of dry sieving for irregular
powder particles or powders in which all or most of the particles have a grain size less than 45 μm.
5.2.5 Light or scanning electron microscopy (SEM) images
This method is already used in industry and research and can be applied synergistically to particle
morphology analysis (see 5.6).
NOTE The number of particles captured and subsequently analysed by image processing software is limited and
it is possible that it is not representative of the entire powder sample.
5.3 Chemical composition
5.3.1 General
The chemical composition relates to the relative amount of elements that constitute a powder or bulk
material. Values are given either in atomic percent (at%) or mass percent (m%). Material properties are
directly related to the chemical composition.
In manufacturing practice, the chemical composition of metal powder feedstock is subject to variation due
to process-related phenomena, such as selective evaporation of individual alloying elements, reactions with
ambient gases (e.g. oxygen, nitrogen) and/or absorption of fumes and spatters (see example for powder bed
fusion in Figure 2).
© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
Key
1 laser beam
2 shielding gas flow (direction is indicative only and can be in other directions, relative to beam travel)
3 powder bed
4 solid
5 melt pool
6 spatter
a
Spatter reacts with O and N , forming O- and N-rich particles which deposit into the powder bed.
2 2
b
O- and N-rich particles.
c
O and N in protective gas atmosphere react with melt pool surface.
2 2
Figure 2 — Impact of spatter during build and effect on chemical composition
The additive manufacturer shall ensure that the chemical composition meets the powder specification limits.
NOTE 1 The powder specification can include chemical composition requirements that differ from those in the
consolidated material specification to compensate for loss or gain of elements during the additive manufacturing
process (e.g. over alloying).
The methods of 5.3.2 to 5.3.6 may be used to determine the chemical composition of the powder samples.
NOTE 2 Refer to ISO/ASTM 52907:2019, Table 2 for further details of suitable test methods.
5.3.2 Combustion methods
Combustion analysis is currently the best available method for analysing the chemical elements C, H, N, and
S. After initial weighing, the sample is catalytically combusted with pure oxygen at high temperatures (up
to 1 800 °C in an exothermic reaction). The combustion gases produced are then transported in a carrier
gas (usually pure helium) through a copper or tungsten contact which is heated to approximately 600 °C to
900 °C. Nitrogen oxides (NOx) contained in the gas stream are completely reduced to molecular nitrogen

© ISO/ASTM International 2024 – All rights reserved
ISO/ASTM 52928:2024(en)
(N ). Then the defined combustion gases (CO , H O, SO , N ) are separated in specific separation columns or
2 2 2 2 2
by gas chromatography and successively fed to a thermal conductivity detector where they are quantified.
With this measurement method, the peaks in the measurement signal can be clearly assigned to the elements
under investigation. Analysis of the peak areas permits a quantitative determination of the individual
elements. Using the known initial mass, the respective mass fraction (in percent or ppm) of the elements C,
H, N, and S in the analysed sample can be precisely calculated.
The carrier-gas heat extraction process is also a combustion method.
5.3.3 Flame AAS
Atom absorption spectrometry (AAS) is an analytical technique that measures the absorption of radiation
(light) by free atoms in the gaseous phase.
The oldest method is flame AAS (FAAS). The sample solution is aspirated into a burner, atomized and
vaporized in the flame. Graphite furnace AAS (GFAAS), also known as electrothermal AAS (ETAAS), is a
similar method in which the sample is atomized in a glowing graphite tube. Both processes are universally
applicable.
5.3.4 X-ray fluorescence spectroscopy (XRF)
XRF, which is also referred to as X-ray fluorescence analysis (XFA) is one of the most widely used methods
for the quantitative and qualitative analysis of the elements in a sample because it is non-destructive and
does not require solutions or dilutions. The limit of detection is approximately one microgram per gram (i.e.
1)
1 ppm ).
5.3.5 Inductively coupled plasma optical emission spectrometry (ICP-OES)
This technique is used for the quantitative and qualitative elemental analysis of solid, liquid, and gaseous
samples. It is based on the principle that excited atoms emit electromagnetic radiation at wavelengths
characteristic for a specific chemical element, thus providing information about the composition of the
sample. The atoms are excited by an inductively coupled plasma (ICP) and the conversion into the plasma
state. With this technique, it is possible to analyse multiple elements simultaneously. Up to 70 elements are
currently achievable.
5.3.6 Energy-dispersive X-ray spectroscopy (EDX)
With energy-dispersive X-ray spectroscopy (EDX) as per test method ASTM F1375, the atoms in the sample
are excited by an electron beam, which causes them to emit X-rays that are characteristic for each element in
the sample. This radiation allows the elemental composition of the sample to be measured.
It is important to note that this analysis yields only limited quantitative findings, which in some
circumstances can produce results that are not sufficiently precise.
NOTE 1 EDX analysis is often used in conjunction with scanning electron microscopy (SEM, see 5.2.5).
NOTE 2 Quantitative analysis can be heavily influenced by the oxide layer on the surface and possibly do not
accurately reflect the entire powder particle.
With this method, only part of a powder particle is analysed rather than
...