ASTM E159-22

Standard Test Method for Loss of Mass in a Reducing Gas Atmosphere for Cobalt, Copper, Tungsten, and Iron Powders (Hydrogen Loss)

SIGNIFICANCE AND USE
5.1 The oxygen content of a powder affects both its green and sintered properties.  
5.2 Hydrogen loss is a term widely used in the powder metallurgy industry even though the measurement represents an approximate oxygen content of the powder.  
5.3 Oxygen is the most common hydrogen-reducible constituent of metal powders, and this procedure may be used as a measure of oxygen, reducible under the test conditions, if other interfering elements are absent.
SCOPE
1.1 This test method covers the determination of the mass of hydrogen-reducible constituents in the following metal powders: cobalt, copper, iron, and tungsten.  
1.2 This test method is useful for cobalt, copper, and iron powders in the range from 0.05 to 3.0 % oxygen, and for tungsten powder in the range from 0.01 to 0.50 % oxygen.  
1.3 This test method does not measure the oxygen contained in oxides such as silicon oxide (SiO2), aluminum oxide (Al2O3), magnesium oxide (MgO), calcium oxide (CaO), titanium dioxide (TiO2), etc. that are not reduced by hydrogen at the test temperatures.  
1.4 For total oxygen content, vacuum or inert gas fusion methods are available (see Test Methods E1019).  
1.5 Untis—The values stated in SI units are to be regarded as the standard.  
1.6 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.  
1.7 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: 31-Aug-2022
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.02 - Base Metal Powders

Relations

• 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 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 E1019-11 - Standard Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Fusion Techniques
• Effective Date: 15-Mar-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 B243-10 - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Jan-2010
• Refers: ASTM B243-09a - Standard Terminology of Powder Metallurgy
• Effective Date: 15-Dec-2009
• Refers: ASTM B243-09 - Standard Terminology of Powder Metallurgy
• Effective Date: 01-Jan-2009

Overview

ASTM E159-22: Standard Test Method for Loss of Mass in a Reducing Gas Atmosphere for Cobalt, Copper, Tungsten, and Iron Powders (Hydrogen Loss) defines a widely recognized procedure for determining the mass loss in metal powders caused by hydrogen-reducible constituents. This loss in mass is typically used as an approximate measure of the oxygen content within metal powders, a critical parameter in the powder metallurgy industry. The method is specifically applicable to cobalt, copper, iron, and tungsten powders within defined oxygen content ranges, helping manufacturers and laboratories ensure high material purity and desirable sintered or green properties.

The test involves exposing metal powder samples to a controlled reducing gas atmosphere, commonly hydrogen, at set temperatures, and measuring the resulting changes in mass. This standard is essential for quality control and material characterization in powder metallurgy and related fields.

Key Topics

• Hydrogen Loss Methodology: The procedure involves subjecting test portions of metal powders to a reducing gas (such as hydrogen) at specified temperatures and durations. The subsequent loss in mass corresponds to the removal of hydrogen-reducible compounds, primarily oxygen.

• Applicability and Limitations:

  • Suitable for the following oxygen content ranges:
    • Cobalt, copper, and iron powders: 0.05% to 3.0% oxygen
    • Tungsten powder: 0.01% to 0.50% oxygen
  • The method does not detect oxygen in oxides such as SiO₂, Al₂O₃, MgO, CaO, or TiO₂, which are not reduced by hydrogen at the testing temperature.

• Interferences: The mass loss can also reflect the removal or volatilization of other elements or compounds (e.g., carbon, sulfur, cadmium, lead, zinc). These must be accounted for to avoid overestimating the oxygen content.

• Precision and Reproducibility: The standard details guidance on repeatability and reproducibility, outlining expected variability both within and between laboratories.

• Reporting and Calculation: Results are reported as percent loss in mass to the nearest 0.01%, with calculated corrections to enhance accuracy.

Applications

• Quality Control in Powder Metallurgy: The hydrogen loss test is crucial for manufacturers to evaluate and control the oxygen content in metal powders, influencing properties such as compressibility, sinterability, and mechanical strength.

• Material Certification and Specification: ASTM E159-22 supports compliance with strict material requirements in high-performance industries, including aerospace, electronics, automotive, and tooling.

• Research and Development: Laboratories use this test method for developing new materials or processing techniques, where the control of oxygen and other reducible impurities is critical for property optimization.

• Routine Analysis: The method is widely adopted as a standard analysis tool in facilities that produce, process, or use cobalt, copper, iron, or tungsten powders.

Related Standards

• ASTM B215: Practices for Sampling Metal Powders
• ASTM B243: Terminology of Powder Metallurgy
• ASTM E177: Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E1019: Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Inert Gas Fusion Techniques

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Keywords: ASTM E159-22, hydrogen loss, metal powders, oxygen content, powder metallurgy, cobalt powder, copper powder, iron powder, tungsten powder, quality control, reducing gas atmosphere, material testing 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: E159 − 22
Standard Test Method for
Loss of Mass in a Reducing Gas Atmosphere for Cobalt,
Copper, Tungsten, and Iron Powders (Hydrogen Loss)
This standard is issued under the fixed designation E159; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* B243Terminology of Powder Metallurgy
E177Practice for Use of the Terms Precision and Bias in
1.1 Thistestmethodcoversthedeterminationofthemassof
ASTM Test Methods
hydrogen-reducible constituents in the following metal pow-
E691Practice for Conducting an Interlaboratory Study to
ders: cobalt, copper, iron, and tungsten.
Determine the Precision of a Test Method
1.2 This test method is useful for cobalt, copper, and iron
E1019Test Methods for Determination of Carbon, Sulfur,
powders in the range from 0.05 to 3.0% oxygen, and for
Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt
tungsten powder in the range from 0.01 to 0.50% oxygen.
Alloys by Various Combustion and Inert Gas Fusion
1.3 Thistestmethoddoesnotmeasuretheoxygencontained Techniques
in oxides such as silicon oxide (SiO ), aluminum oxide
3. Terminology
(Al O ), magnesium oxide (MgO), calcium oxide (CaO),
2 3
3.1 Definitions—Definitions of powder metallurgy terms
titanium dioxide (TiO ), etc. that are not reduced by hydrogen
can be found in Terminology B243. Additional descriptive
at the test temperatures.
information on powder metallurgy is available under “General
1.4 For total oxygen content, vacuum or inert gas fusion
Information on PM” on the ASTM B09 web page.
methods are available (see Test Methods E1019).
4. Summary of Test Method
1.5 Untis—The values stated in SI units are to be regarded
as the standard.
4.1 This test method consists of subjecting a test portion of
powder to the action of a hydrogen-containing gas under
1.6 This standard does not purport to address all of the
standardconditionsoftemperatureandtimeandmeasuringthe
safety concerns, if any, associated with its use. It is the
resulting loss of mass.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
5. Significance and Use
mine the applicability of regulatory limitations prior to use.
5.1 The oxygen content of a powder affects both its green
1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard- and sintered properties.
ization established in the Decision on Principles for the
5.2 Hydrogen loss is a term widely used in the powder
Development of International Standards, Guides and Recom-
metallurgy industry even though the measurement represents
mendations issued by the World Trade Organization Technical
an approximate oxygen content of the powder.
Barriers to Trade (TBT) Committee.
5.3 Oxygen is the most common hydrogen-reducible con-
stituent of metal powders, and this procedure may be used as a
2. Referenced Documents
measureofoxygen,reducibleunderthetestconditions,ifother
2.1 ASTM Standards:
interfering elements are absent.
B215Practices for Sampling Metal Powders
6. Interferences
6.1 If carbon or sulfur is present, or both are present, they
This test method is under the jurisdiction of ASTM Committee B09 on Metal
will be largely removed in the test. Their loss in mass is
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.02 on Base Metal Powders.
included in the total loss in mass measurement and must be
Current edition approved Sept. 1, 2022. Published September 2022. Originally
subtracted from the total mass loss.
approved in 1986. Last previous edition approved in 2017 as E159–17. DOI:
10.1520/E0159-22.
6.2 If metals or compounds are present that vaporize at the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
testtemperature(suchascadmium,lead,zinc,etc.),theireffect
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
is included in the loss of mass measurement and must be
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. subtracted from the total mass loss.
*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
E159 − 22
6.3 If some components are present that are oxidized or 10.2 Pass the nitrogen through the combustion tube for a
hydrided during the test, there is a gain in mass that must be period of at least 1min before inserting the combustion boat at
added to the total mass loss. the center of the zone of uniform temperature of the furnace.
10.2.1 For cobalt, the temperature is 875°C.
7. Apparatus
10.2.2 For copper, the temperature is 875°C.
10.2.3 For iron, the temperature is 1120°C.
7.1 Furnace, capable of operating at the prescribed tem-
10.2.4 For tungsten, the temperature is 1120°C.
perature.
10.3 Ensure that the pilot flames at both ends of the tube
7.2 Temperature Control, capable of maintaining tempera-
furnace are lit and then start the flow of reducing gas and stop
tures to 615°C.
the flow of nitrogen. Record the time when the reducing gas is
7.3 Gastight Ceramic or Metallic Combustion Tube.
introduced. The flow rate of the reducing gas should be 10 to
7.4 Flow Meter, to measure flow of reducing gas.
30mL⁄s.
7.5 Combustion Boat, composed of alundum, quartz, or 10.4 Maintain a positive flow of reducing gas through the
nickel, depending on the test conditions. The boat shall be of
system for the time of reduction during which the temperature
such dimensions, for example 75 mm long and 12 mm wide, of the furnace shall be held within 615°C of the target
that the thickness of powder, when uniformly distributed, does
reduction temperature.
not exceed 3mm. 10.4.1 For cobalt, the time shall be 30 min.
10.4.2 For copper, the time shall be 30 min.
7.6 Balance, readable to 0.0001g with a capacity of at least
10.4.3 For iron, the time shall be 60 min.
100g.
10.4.4 For tungsten, the time shall be 60 min.
8. Reagents
10.5 At the end of the prescribed time, discontinue the flow
of reducing gas and restart the flow of nitrogen into the tube.
8.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
10.6 After nitrogen has been flowing through the combus-
all reagents shall conform to the specifications of the Commit-
tion tube for at least 1 min, open the tube and withdraw the
tee onAnalytical Reagents of theAmerican Chemical Socie
...

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: E159 − 17 E159 − 22
Standard Test Method for
Loss of Mass in a Reducing Gas Atmosphere for Cobalt,
Copper, Tungsten, and Iron Powders (Hydrogen Loss)
This standard is issued under the fixed designation E159; 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 mass of hydrogen-reducible constituents in the following metal powders:
cobalt, copper, iron, and tungsten.
1.2 This test method is useful for cobalt, copper, and iron powders in the range from 0.05 to 3.0 % oxygen, and for tungsten
powder in the range from 0.01 to 0.50 % oxygen.
1.3 This test method does not measure the oxygen contained in oxides such as silicon oxide (SiO ), aluminum oxide (Al O ),
2 2 3
magnesium oxide (MgO), calcium oxide (CaO), titanium dioxide (TiO ), etc. that are not reduced by hydrogen at the test
temperatures.
1.4 For total oxygen content, vacuum or inert gas fusion methods are available (see Test Methods E1019).
1.5 Untis—The values stated in SI units are to be regarded as the standard.
1.6 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.
1.7 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
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
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by
Various Combustion and Inert Gas Fusion Techniques
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, 2017Sept. 1, 2022. Published April 2017September 2022. Originally approved in 1986. Last previous edition approved in 20102017 as
E159 – 10.E159 – 17. DOI: 10.1520/E0159-17.10.1520/E0159-22.
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.
*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
E159 − 22
3. Terminology
3.1 Definitions—Definitions of powder metallurgy terms can be found in Terminology B243. Additional descriptive information
on powder metallurgy is available in the Related Material section of Vol 02.05 of the under “General Information on PM” on the
Annual Book of ASTM Standards.ASTM B09 web page.
4. Summary of Test Method
4.1 This test method consists of subjecting a test portion of powder to the action of a hydrogen-containing gas under standard
conditions of temperature and time and measuring the resulting loss of mass.
5. Significance and Use
5.1 The oxygen content of a powder affects both its green and sintered properties.
5.2 Hydrogen loss is a term widely used in the powder metallurgy industry even though the measurement represents an
approximate oxygen content of the powder.
5.3 Oxygen is the most common hydrogen-reducible constituent of metal powders, and this procedure may be used as a measure
of oxygen, reducible under the test conditions, if other interfering elements are absent.
6. Interferences
6.1 If carbon or sulfur is present, or both,both are present, they will be largely removed in the test. Their loss in mass is included
in the total loss in mass measurement and must be subtracted from the total mass loss.
6.2 If metals or compounds are present that vaporize at the test temperature (such as cadmium, lead, zinc, etc.), their effect is
included in the loss of mass measurement and must be subtracted from the total mass loss.
6.3 If some components are present that are oxidized or hydrided during the test, there is a gain in mass that must be added to
the total mass loss.
7. Apparatus
7.1 Furnace, capable of operating at the prescribed temperature.
7.2 Temperature Control, capable of maintaining temperatures to 615 °C.
7.3 Gastight Ceramic or Metallic Combustion Tube.
7.4 Flow Meter, to measure flow of reducing gas.
7.5 Combustion Boat, composed of alundum, quartz, or nickel, depending on the test conditions. The boat shall be of such
dimensions, for example 75 mm long and 12 mm wide, that the thickness of powder, when uniformly distributed, does not exceed
3 mm.3 mm.
7.6 Balance, suitable for determining mass to the nearest 0.0001 g.readable to 0.0001 g with a capacity of at least 100 g.
8. Reagents
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, where
E159 − 22
such specifications are available. 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 Dissociated Ammonia, Dissociated Ammonia,having a dew point lower than − 40 °C. May be used interchangeably with the
hydrogen specified in section 8.3.
8.3 Hydrogen, having an oxygen content less than 20 ppm and a dew point lower than −40 °C.
8.4 Nitrogen, having an oxygen content less than 20 ppm and a dew point lower than −40 °C.
9. Test Portion
9.1 Obtain the test portion in accordance with the procedure described in Practices B215.
9.2 The test portion shall weigh approximately 5 g.5 g.
10. Procedure
10.1 Spread the test portion to a uniform depth in a combustion boat that has been preconditioned to a constant mass and weighed
record the mass to the nearest 0.0001 g. 0.0001 g. The depth of powder in the boat should be approximately 3 mm. Weigh the
Record the mass of the boat and specimen to the nearest 0.0001 g.0.0001 g.
10.2 Pass the nitrogen through the combustion tube for a period of at least 1 min 1 min before inserting the combustion boat at
the center of the zone of uniform temperature of the furnace.
10.2.1 For cobalt, the temperature is 875 °C.
10.2.2 For copper, the temperature is 875 °C.
10.2.3 For iron, the temperature is 1120 °C.
10.2.4 For tungsten, the temperature is 1120 °C.
10.3 Ensure that the pilot flames at both ends of the tube furnace are lit and then start the flow o
...