1、Designation: E 1569 03Standard Test Method forDetermination of Oxygen in Tantalum Powder1This standard is issued under the fixed designation E 1569; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of oxygen intantalum powder in concentrations from 0.05 to 0.50 %.1.2 This standard does not purp
3、ort to address all of thesafety problems, 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 applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:E 29
4、 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2E 50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of Metals3E 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method23. Summary
5、 of Test Method3.1 This test method is intended for use with automated,commercially available inert gas fusion analyzers.3.2 The sample, plus flux, is fused in a graphite crucibleunder a flowing inert gas stream at a temperature sufficient torelease oxygen. The released oxygen combines with carbonfr
6、om the crucible to form CO that is swept by the inert gasstream into either an infrared or thermal conductivity detector.The detector output is compared to that of calibration referencematerials and the result is displayed as percent oxygen.3.3 In an instrument whose detection is based upon thermalc
7、onductivity (see Fig. 1), the sample gases are passed throughheated rare earth copper oxide that converts CO to CO2. Thewater produced during fusion is absorbed onto magnesiumperchlorate and the remaining nitrogen and carbon dioxide areseparated chromatographically. The nitrogen elutes first andcan
8、be measured (on a dual capability instrument) or disre-garded. The oxygen, as CO2, enters the measuring cell last andthe thermistor bridge output is integrated and processed todisplay percent oxygen.3.4 In a typical instrument based on infrared detection (seeFig. 2), the sample is fused in a stream
9、of argon and passeddirectly into an infrared cell through which infrared energy istransmitted. The CO in the sample gases absorbs some of thetransmitted infrared energy and the decrease in energy reachingthe detector is processed and displayed directly as percentoxygen.4. Significance and Use4.1 Thi
10、s test method is primarily intended as a test forcompliance with compositional specifications. It is assumedthat all who use this method will be trained analysts capable ofperforming common laboratory procedures skillfully andsafely. It is expected that the work will be performed in aproperly equipp
11、ed laboratory.5. Interferences5.1 The elements usually present in this material do notinterfere but there is some evidence to suggest that low-purityflux can act as a getter of the released oxygen.6. Apparatus6.1 Fusion and Measurement Apparatus The generalfeatures of the instrument used in developi
12、ng this test methodare shown in Figs. 1 and 2.6.2 CapsulesThe capsules must be made of high-puritytin.6.3 CruciblesThe crucibles must be made of high-puritygraphite and be of the dimensions recommended by themanufacturer.6.4 FluxThe foil or baskets must be made of high-puritynickel and in the case o
13、f the baskets, the dimensions must meetthe requirements of the automatic sample drop, if present onthe instrument.6.5 TweezersSolvent and acid-resistant plastic.7. Reagents7.1 Acetic AcidReagent grade.7.2 AcetoneResidue after evaporation must be less than0.0005 %.1This test method is under the juris
14、diction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.06 on Ti, Zr, W, Mo, Ta, Nb, Hf.Current edition approved June 10, 2003. Published August 2003. Last previousedition approved in 1998 as E 156993 (1998).2An
15、nual Book of ASTM Standards, Vol 14.02.3Annual Book of ASTM Standards, Vol 03.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.AInert Gas Supply ISample Holding ChamberBPressure Regulator JElectrode FurnaceCHeated Copper KDust Filt
16、erDSodium Hydroxide Impregnated Clay LHeated Rare Earth Copper OxideEMagnesium Perchlorate MMagnesium PerchlorateFFlow Control NSilica ColumnGFlow Manifold OThermal Conductivity Detector/ReadoutHOptional Gas Doser PFlow RotameterManifold Porting1to4Crucible Degas Flow $ 5to23to61to6Fusion Flow $ 5to
17、43and2offFIG. 1 Apparatus for the Determination of Oxygen by the Inert Gas FusionThermal Conductivity MethodE1569032AInert Gas Supply JFlow ManifoldBPressure Regulator 2 Stage KSample Holding ChamberCSodium Hydroxide Impregnated Clay LElectrode FurnaceDMagnesium Perchlorate MDust FilterEFlow Restric
18、tor NHeated Rare Earth Copper OxideFFlow Meter OFlow ControlGPressure Regulator PIR Detector/ReadoutHNeedle ValveIOptional Gas DoserManifold Porting2to4Crucible Degas Flow $ 5to31to61to4Fusion Flow $ 5to62and3offFIG. 2 Apparatus for the Determination of Oxygen by the Inert Gas FusionInfrared Absorpt
19、ion MethodE15690337.3 Inert GasUse the purity and type specified by theinstrument manufacturer.7.4 Magnesium Perchlorate, Anhydrous4Mg(ClO4)22Used in the instrument to absorb water. Use the purity specifiedby the instrument manufacturer.7.5 Nickel Flux Cleaning Solution Prepare a fresh solu-tion of
20、nickel cleaning solution by combining 75 mL of aceticacid, 25 mL of HNO3, and 2 mL of HCl. Discard after use.7.6 Sodium Hydroxide on Clay5Reagent used to absorbCO2. Use a purity specified by the instrument manufacturer.8. Preparation of Apparatus8.1 Assemble the apparatus as recommended by the manu-
21、facturer. Make the required power, gas, and water connections.Turn on the instrument and allow sufficient time to stabilize theequipment.8.2 Change the chemical traps and filters as required. Testthe furnace and analyzer to ensure the absence of leaks. Makea minimum of two test runs using a sample a
22、s directed in 12.3and 12.4 to condition the newly changed filters before attempt-ing to calibrate the system or to determine the value of theblank.9. Flux Preparation9.1 Immerse the flux in nickel flux cleaning solution (see7.5) for 50 to 60 s, then rinse in running water for 2 to 3 min.Pour flux on
23、to paper towels to remove excess water.9.2 Place flux in sealable glass container, rinse with acetone,and decant. Replace with fresh acetone and store flux underacetone until used (see Notes 1 and 2).NOTE 1Nickel is necessary to flux the tantalum fusion reaction but itmust be cleaned because signifi
24、cant oxidation can be present on thesurface of the baskets or foil to interfere with the analysis.NOTE 2The fluxing agent must be of proper size to be introducedthrough the sample drop mechanism and into the graphite crucible.10. Sample Preparation10.1 During the weighing and introduction of the sam
25、plepowder into the tin capsule and nickel basket or foil the entireoperation must be accomplished using clean tweezers only.Never touch the flux/sample package with the fingers.11. Calibration11.1 Selection of reference materials is currently limited tosolid steel pins with oxygen content ranging fr
26、om approxi-mately 0.01 to 0.05 %. The analyst must be aware that thecomposition of the reference materials is not that of theunknowns.11.2 Gas DosingAutomatic and manual gas dosing, rec-ommended by some manufacturers, can be used to set up theinstrument, but instrument response must be verified with
27、standards because of the fusion characteristics of the furnace/sample combination.11.3 Initial Adjustment of Measurement SystemWeigh asteel pin reference material to the nearest milligram andtransfer it to an outgassed graphite crucible (some instrumentsallow for the use of an automatic sample drop
28、port). Proceed asdirected in 12.3 and 12.4. Repeat 12.3 and 12.4 until anabsence of drift is indicated. Using the last three analyses,adjust the instrument signal to provide a reading within therange of the certified value of the reference material. (Outgas-sing is accomplished automatically either
29、as part of thecontinuous analysis cycle, used with the automatic sampledrop, or as the first step in a two-stage cycle associated with themanual addition of the sample to the crucible.)11.4 Determination of Flux and Crucible BlankProceedas directed in 12.3 and 12.4 for the determination of the entir
30、ereagent blank which consists of the type of crucibles, flux, andcapsules which will be used in all subsequent analyses. Thecapsule is folded and the excess air is squeezed out. Thecapsule is placed within the nickel basket and the package isweighed to the nearest 1 mg. If nickel foil is used, the w
31、eightof the foil must be the same as that used for the specimenanalysis and the foil is wrapped around the capsule beforeweighing. Determine the average blank of three individual runsestablishing that the blank is low, less than 3 g of oxygen, andconsistent. Enter this value into the appropriate mec
32、hanism ofthe analyzer. Problems with inconsistent or high blank values,generally indicative of reagent depletion, must be correctedbefore the analysis can be continued. If the unit does not havethis provision for automatic blank compensation, then theblank value must be manually subtracted from the
33、total resultprior to any other calculation.11.5 CalibrationFollow the calibration procedure recom-mended by the manufacturer using a steel pin referencematerial of a concentration different from that of 11.3. Analyzespecimens until the maximum range between readings is0.001 %. Confirm the calibratio
34、n by analyzing an additionalspecimen after the calibration procedure is complete. Theresults should fall within the maximum allowable limit of thereference material. If not, refer to the manufacturers instruc-tions for checking linearity.12. Procedure12.1 Assemble the apparatus, calibrate it, and te
35、st theperformance as directed in Sections 8 and 11.12.2 Transfer 0.08 to 0.15 g of sample powder (the weightof nickel must exceed the weight of the sample by at least afactor of ten) to a tin capsule. Fold the capsule over, squeezingthe excess air out, and insert into a nickel basket, or wrap innick
36、el foil.12.3 Place the specimen into the automatic sample drop portor into an outgassed crucible.12.4 Place the crucible on the furnace pedestal, raise themechanism, and start the analysis cycle. Refer to the specificinstructions for your instrument regarding operation, entry ofsample weight, and bl
37、ank value.13. Calculation13.1 Refer to the manufacturers instructions to ensure thatall essential variables in the analyses have been accounted for.The output of most modern fusion equipment is given directlyin percent oxygen so that post-analysis calculations are nor-mally not required.4Known comme
38、rcially as Anhydrone.5Known commercially as Ascarite II.E156903414. Precision and Bias614.1 PrecisionTen laboratories cooperated in testing fourdifferent samples, and the data obtained are presented in Table1. The testing and statistical analyses were performed inaccordance with the provisions of Pr
39、actice E 691.14.2 BiasNo bias can be evaluated, since the samplesused for the round robin had no established values assigned tothem.15. Keywords15.1 oxygen content; tantalum; tantalum powderASTM International takes no position respecting the validity of any patent rights asserted in connection with
40、any item mentionedin this standard. Users of this standard are 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 technic
41、al committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration
42、 at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbo
43、r Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).6Supporting data have been filed at ASTM Headquarters. Request RR:E01-1008.TABLE 1 Statistical InformationOxygen in Tantalum PowderTest MaterialOxygen Found,ppmRepeatability, r Reproducibility, RA 1420 81 83B 2079 78 136C 2490 89 151D 2990 118 144E1569035
