1、Designation: E159 10E159 17Standard Test Method forLoss of Mass in a Reducing Gas Atmosphere for Cobalt,Copper, Tungsten, and Iron Powders (Hydrogen Loss)1This standard is issued under the fixed designation E159; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript 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
3、 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 tungstenpowder in the range from 0.01 to 0.50 % oxygen.1.3 This test method does not measure the oxygen
4、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 testtemperatures.1.4 For total oxygen content, vacuum or inert gas fusion methods are available (see Test Methods
5、 E1019).1.5 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 responsibilityof the user of this standard to establish appropriate safety and health practices and determ
6、ine the applicability of regulatorylimitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations is
7、suedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE1
8、019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys byVarious Combustion and Fusion Techniques3. Terminology3.1 DefinitionsDefinitions of powder metallurgy terms can be found in Terminology B243.Additional descriptive informationon pow
9、der metallurgy is available in the Related Material section of Vol 02.05 of the Annual Book of ASTM Standards.4. Summary of Test Method4.1 This test method consists of subjecting a sample test portion of powder to the action of a hydrogen-containing gas understandard conditions of temperature and ti
10、me and measuring the resulting loss of mass.5. Significance and Use5.1 The oxygen content of a powder affects both its green and sintered properties.1 This test method is under the jurisdiction ofASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcom
11、mittee B09.02on Base Metal Powders.Current edition approved July 1, 2010April 1, 2017. Published August 2010April 2017. Originally approved in 1986. Last previous edition approved in 20062010 asE159 06.E159 10. DOI: 10.1520/E0159-10.10.1520/E0159-17.2 For referencedASTM standards, visit theASTM webs
12、ite, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicatio
13、n of what changes have been made to the previous version. Becauseit 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 versionof the standard as published by ASTM is to be consid
14、ered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 Hydrogen loss is a term widely used in the powder metallurgy industry even though the meas
15、urement represents anapproximate 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 measureof oxygen, reducible under the test conditions, if other interfering elements are absent.6. Interferences6.1 If carb
16、on or sulfur is present, or both, are present, they will be largely removed in the test. Their loss in mass is includedin 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,
17、lead, zinc, etc.), their effect isincluded 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 tothe total mass loss.7. Apparatus7.1 Furnace, capab
18、le 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 hydrogen.reducing gas.7.5 Combustion Boat, composed of alundum, quartz, or nickel, depending on the
19、test conditions. The boat shall be of suchdimensions, for example 75 mm long and 12 mm wide, that the thickness of powder, when uniformly distributed, does not exceed3 mm.7.6 Balance, suitable for determining mass to the nearest 0.0001 g.8. Reagents8.1 Purity of ReagentsReagent grade chemicals shall
20、 be used in all tests. Unless otherwise indicated, it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, wheresuch specifications are available.3 Other grades may be used, provided it is first ascertained that th
21、e reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.8.2 Dissociated Ammonia, having a dew point lower than 40 C. May be used interchangeably with the hydrogen specifiedin section 8.3.8.3 Hydrogen, having an oxygen content less than 20 ppm and
22、 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 SpecimenPortion9.1 Obtain the test specimenportion in accordance with the procedure described in Practices B215.9.2 The test specimenportion shall weigh approximately 5 g.10.
23、Procedure10.1 Spread the test specimenportion to a uniform depth in a combustion boat that has been preconditioned to a constant massand weighed to the nearest 0.0001 g. The depth of powder in the boat should be approximately 3 mm. Then weigh Weigh the boatand specimen to the nearest 0.0001 g.10.2 P
24、ass the nitrogen through the combustion tube for a period of at least 1 min before inserting the combustion boat at thecenter 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
25、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 of hydrogen reducing gas andstop the flow of nitrogen. Record the time when the hydrogen is introduced. reducing gas is introduced. The flow rate o
26、f thereducing gas should be 10 to 30 mL/min.3 Reagent Chemicals, American Chemical Society Specifications , American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed bythe American Chemical Society, see Reagent Chemicals and Standards, by Joseph Rosin, D. Van N
27、ostrand Co., Inc., New York, NY., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.E159 17210.4 Maintain a positive flow of hydrogen reducing gas through the system for the time of reduction during which thetemperature of the furnace
28、 shall be held within 615 C.615 C of the target reduction temperature.10.4.1 For cobalt, the time shall be 30 min.10.4.2 For copper, the time shall be 30 min.10.4.3 For iron, the time shall be 60 min.10.4.4 For tungsten, the time shall be 60 min.10.5 At the end of the prescribed time, discontinue th
29、e flow of hydrogen reducing gas and restart the flow of nitrogen into thetube.10.6 After nitrogen has been flowing through the combustion tube for at least 1 min, open the tube and withdraw the boat undernitrogen atmosphere to the cooler part of the combustion tube.10.7 Allow the specimen to cool in
30、 the nitrogen atmosphere for 15 to 30 min, then remove the specimen from the tube andpermit it to cool to room temperature in a desiccator.10.8 When the boat has cooled to room temperature, reweigh it to the nearest 0.0001 g.11. Calculation11.1 Calculate the mass loss as follows:Loss in mass,%5A2BA2
31、C 3100 (1)where:A = original mass of boat and powder specimen, g;B = mass of boat and powder specimen after reduction, g; andC = original mass of the boat, g.11.2 If the loss of mass value calculated in 11.1 is to be used as the oxygen content of the powder, correct the value obtainedin accordance w
32、ith 6.1 6.3.12. Report12.1 Results shall be reported as percent loss in mass to the nearest 0.01 %.13. Precision and Bias13.1 A statement of precision provides guidelines as to the kind of variability that can be expected between test results whenthe method is used in one or more reasonably competen
33、t laboratories.13.2 The precision of this test method has not been determined by a statistically valid interlaboratory test because of the limitednumber of participating laboratories (less than six).13.3 The following precision data were developed using the procedures contained in Test Method E159 f
34、rom an interlabortorytest conducted by four laboratories in 1994. The percent loss in mass in hydrogen was determined for four samples, a cobaltpowder, a copper powder, an iron powder, and a tungsten powder. Except for the use of only four laboratories, Practice E691 wasfollowed for the design and a
35、nalysis of the data. The details are given in an ASTM research report.13.4 The precision information given below is for the results. The results were obtained from the running of three replicates byeach lab on each sample.Cobalt Copper Iron TungstenAverage, % 0.45 0.15 0.22 0.47r, % 0.03 0.03 0.03 0
36、.09R, % 0.12 0.03 0.07 0.1113.5 Repeatability, r, is a measure of the variability between test results obtained within a single laboratory in the shortestpractical period of time by a single operator with a specific set of test apparatus using test specimens taken at random from a singlequantity of
37、homogeneous material.13.6 Reproducibility, R, is a measure of the variability between test results obtained in different laboratories using testspecimens taken at random from a single quantity of homogeneous material.13.7 Bias cannot be stated since there is no certified reference material.14. Keywo
38、rds14.1 chemical analysis; cobalt powder; copper powder; hydrogen loss; iron powder; metal powders; oxygen content; tungstenpowderE159 173SUMMARY OF CHANGESCommittee B09 has identified the location of selected changes to this standard since the last issue(E159 - 06E159 - 10) that may impact the use
39、of this standard. (July(April 1, 2010)2017)(1) Changed the title and replaced Replaced “hydrogen” with “a reducing gas atmosphere.”“ reducing gas” throughout thestandard.(2) SubsectionReplaced 1.5Deleted the reference to units in parentheses.“specimen” with “portion” throughout the standard.(3) Subs
40、ectionReplaced 7.6Changed the accuracy of the“sample” with “test portion” in 4.1balance required for weighing from0.001 g to 0.0001 g(4) Subsection 10.110.3Changed (two places) from weighing to the nearest 0.001 g to weighing to the nearest 0.0001 g.Addedreducing gas flow rate.(5) Subsection 10.310.
41、4Inserted verbiage concerning ensuring that pilot flames are lit at both ends of the tube furnace before thehydrogen is introduced.Clarified the furnace temperature.(6) Subsection 10.8Changed weighing to the nearest 0.001 g to weighing to the nearest 0.0001 g.(7) Subsection 10.9Deleted reference to
42、the alternative procedure.(Sections 10.9.1 through 10.9.6 removed).(8) Subsection 11.2Changed “hydrogen loss” to “loss of mass.”ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are
43、 expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not r
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