1、Designation: E159 10Standard 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 or, in
2、 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 ofhydrogen-reducible constit
3、uents in the following metal pow-ders: cobalt, copper, iron, and tungsten.1.2 This test method is useful for cobalt, copper, and ironpowders in the range from 0.05 to 3.0 % oxygen, and fortungsten powder in the range from 0.01 to 0.50 % oxygen.1.3 This test method does not measure the oxygen contain
4、edin oxides such as silicon oxide (SiO2), aluminum oxide(Al2O3), magnesium oxide (MgO), calcium oxide (CaO),titanium dioxide (TiO2), etc. that are not reduced by hydrogenat the test temperatures.1.4 For total oxygen content, vacuum or inert gas fusionmethods are available (see Test Methods E1019).1.
5、5 The values stated in SI units are to be regarded as thestandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the app
6、lica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE1019 Test Methods for Determina
7、tion of Carbon, Sulfur,Nitrogen, and Oxygen in Steel, Iron, Nickel, and CobaltAlloys by Various Combustion and Fusion Techniques3. Terminology3.1 DefinitionsDefinitions of powder metallurgy termscan be found in Terminology B243. Additional descriptiveinformation on powder metallurgy is available in
8、the RelatedMaterial section of Vol 02.05 of the Annual Book of ASTMStandards.4. Summary of Test Method4.1 This test method consists of subjecting a sample ofpowder to the action of a hydrogen-containing gas understandard conditions of temperature and time and measuring theresulting loss of mass.5. S
9、ignificance and Use5.1 The oxygen content of a powder affects both its greenand sintered properties.5.2 Hydrogen loss is a term widely used in the powdermetallurgy industry even though the measurement representsan approximate oxygen content of the powder.5.3 Oxygen is the most common hydrogen-reduci
10、ble con-stituent of metal powders, and this procedure may be used as ameasure of oxygen, reducible under the test conditions, if otherinterfering elements are absent.6. Interferences6.1 If carbon or sulfur is present, or both, are present, theywill be largely removed in the test. Their loss in mass
11、isincluded in the total loss in mass measurement and must besubtracted from the total mass loss.6.2 If metals or compounds are present that vaporize at thetest temperature (such as cadmium, lead, zinc, etc.), their effectis included in the loss of mass measurement and must besubtracted from the tota
12、l mass loss.6.3 If some components are present that are oxidized orhydrided during the test, there is a gain in mass that must beadded to the total mass loss.7. Apparatus7.1 Furnace, capable of operating at the prescribed tem-perature.1This test method is under the jurisdiction of ASTM Committee B09
13、 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base Metal Powders.Current edition approved July 1, 2010. Published August 2010. Originallyapproved in 1986. Last previous edition approved in 2006 as E159 06. DOI:10.1520/E0159-10.2For referenced
14、ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright
15、ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 Temperature Control, capable of maintaining tempera-tures to 615 C.7.3 Gastight Ceramic or Metallic Combustion Tube.7.4 Flow Meter, to measure flow of hydrogen.7.5 Combustion Boat, composed of
16、 alundum, quartz, ornickel, depending on the test conditions. The boat shall be ofsuch dimensions, for example 75 mm long and 12 mm wide,that the thickness of powder, when uniformly distributed, doesnot exceed 3 mm.7.6 Balance, suitable for determining mass to the nearest0.0001 g.8. Reagents8.1 Puri
17、ty of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused,
18、 provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Dissociated Ammonia, having a dew point lowerthan 40 C. May be used interchangeably with the hydrogenspecified in section 8.3.8.3 Hydrogen, having
19、 an oxygen content less than 20 ppmand a dew point lower than 40 C.8.4 Nitrogen, having an oxygen content less than 20 ppmand a dew point lower than 40 C.9. Test Specimen9.1 Obtain the test specimen in accordance with the proce-dure described in Practices B215.9.2 The test specimen shall weigh appro
20、ximately 5 g.10. Procedure10.1 Spread the test specimen to a uniform depth in acombustion boat that has been preconditioned to a constantmass and weighed to the nearest 0.0001 g.The depth of powderin the boat should be approximately 3 mm. Then weigh theboat and specimen to the nearest 0.0001 g.10.2
21、Pass the nitrogen through the combustion tube for aperiod of at least 1 min before inserting the combustion boat atthe 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
22、1120 C.10.2.4 For tungsten, the temperature is 1120 C.10.3 Ensure that the pilot flames at both ends of the tubefurnace are lit and then start the flow of hydrogen and stop theflow of nitrogen. Record the time when the hydrogen isintroduced.10.4 Maintain a positive flow of hydrogen through thesystem
23、 for the time of reduction during which the temperatureof the furnace shall be held within 615 C.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 pres
24、cribed time, discontinue the flowof hydrogen and restart the flow of nitrogen into the tube.10.6 After nitrogen has been flowing through the combus-tion tube for at least 1 min, open the tube and withdraw theboat under nitrogen atmosphere to the cooler part of thecombustion tube.10.7 Allow the speci
25、men to cool in the nitrogen atmospherefor 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, re-weigh it to the nearest 0.0001 g.11. Calculation11.1 Calculate the mass loss as follows:Loss i
26、n mass, % 5A BA C3 100 (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 usedas the oxygen content of the powder, correct the value obtainedi
27、n accordance with 6.1-6.3.12. Report12.1 Results shall be reported as percent loss in mass to thenearest 0.01 %.13. Precision and Bias13.1 A statement of precision provides guidelines as to thekind of variability that can be expected between test resultswhen the method is used in one or more reasona
28、bly competentlaboratories.13.2 The precision of this test method has not been deter-mined by a statistically valid interlaboratory test because of thelimited number of participating laboratories (less than six).13.3 The following precision data were developed using theprocedures contained in Test Me
29、thod E159 from an interlabor-tory test conducted by four laboratories in 1994. The percentloss in mass in hydrogen was determined for four samples, acobalt powder, a copper powder, an iron powder, and atungsten powder. Except for the use of only four laboratories,Practice E691 was followed for the d
30、esign and analysis of thedata. The details are given in an ASTM research report.3Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by theAmerican Chemical Society, see Reagent Chemicals and Sta
31、ndards,byJoseph Rosin, D. Van Nostrand Co., Inc., New York, NY., and the United StatesPharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc.(USPC), Rockville, MD.E159 10213.4 The precision information given below is for theresults. The results were obtained from the running of thre
32、ereplicates by each lab on each sample.Cobalt Copper Iron TungstenAverage, % 0.45 0.15 0.22 0.47r, % 0.03 0.03 0.03 0.09R, % 0.12 0.03 0.07 0.1113.5 Repeatability, r, is a measure of the variability betweentest results obtained within a single laboratory in the shortestpractical period of time by a
33、single operator with a specific setof test apparatus using test specimens taken at random from asingle quantity of homogeneous material.13.6 Reproducibility, R, is a measure of the variabilitybetween test results obtained in different laboratories using testspecimens taken at random from a single qu
34、antity of homoge-neous material.13.7 Bias cannot be stated since there is no certifiedreference material.14. Keywords14.1 chemical analysis; cobalt powder; copper powder;hydrogen loss; iron powder; metal powders; oxygen content;tungsten powderSUMMARY OF CHANGESCommittee B09 has identified the locati
35、on of selected changes to this standard since the last issue (E159 - 06)that may impact the use of this standard. (July 1, 2010)(1) Changed the title and replaced “hydrogen” with “a reduc-ing gas atmosphere.”(2) Subsection 1.5Deleted the reference to units in paren-theses.(3) Subsection 7.6Changed t
36、he accuracy of the balancerequired for weighing from 0.001 g to 0.0001 g.(4) Subsection 10.1Changed (two places) from weighing tothe nearest 0.001 g to weighing to the nearest 0.0001 g.(5) Subsection 10.3Inserted verbiage concerning ensuringthat pilot flames are lit at both ends of the tube furnace
37、beforethe hydrogen is introduced.(6) Subsection 10.8Changed weighing to the nearest 0.001 gto weighing to the nearest 0.0001 g.(7) Subsection 10.9Deleted reference to the alternative pro-cedure.(Sections 10.9.1 through 10.9.6 removed).(8) Subsection 11.2Changed “hydrogen loss” to “loss ofmass.”ASTM
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