ASTM_B_890_-_07_2012.pdf

Designation:B89007(Reapproved 2012)Standard Test Method forDetermination of Metallic Constituents of Tungsten Alloysand Tungsten Hardmetals by X-Ray FluorescenceSpectrometry1This standard is issued under the fixed designation B890;the number immediately following the designation indicates the year oforiginal adoption 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.Scope1.1 This test method describes a procedure for the determi-nation of the concentration,generally reported as mass percent,of the metallic constituents of tungsten-based alloys andhardmetals utilizing wavelength dispersive X-ray fluorescencespectrometry(XRF).This test method incorporates the prepa-ration of standards using reagent grade metallic oxides,lithium-borate compounds,and fusion techniques.This testmethod details techniques for preparing representative speci-mens of both powder and sintered tungsten-based material.This test method is accurate for a wide range of compositions,and can be used for acceptance of material to grade specifica-tions.1.2 This test method is applicable to mixtures of tungsten ortungsten carbide with additions of refractory metal carbidesand binder metals.Table 1 lists the most common elementalconstituents and their concentration range.Note that many ofthese occur as metallic carbides.1.3 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 applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE1361 Guide for Correction of Interelement Effects inX-Ray Spectrometric Analysis2.2 Handbook of Chemistry and Physics,367th ed3.Terminology3.1 For definitions of terms used in this test method,refer toTerminology E135.4.Summary of Test Method4.1 A suite of standards which closely match the chemicalcontent of the material to be analyzed are prepared usingreagent grade metallic oxides.Test samples are oxidized in ahigh-temperature furnace open to air.Fused glass specimensare prepared for these standards and for the test samples to beanalyzed.These specimens of oxidized tungsten or tungstencarbide alloys are irradiated with an energetic primary X-raybeam.The intensity of the resultant secondary X-rays,charac-teristic in energy,for each elemental constituent is measured bymeans of a suitable detector or combination of detectors afterdiffraction by a Bragg spectrometer.The concentration of eachconstituent element is calculated by comparison with standardsamples which closely match the chemical content of theanalyzed material.The calculation may be manual,incorporatea calibration curve,or be performed by a computer programwhich incorporates correction routines for X-ray absorptionand enhancement effects(see Guide E1361).5.Significance and Use5.1 This test method allows the determination of the chemi-cal composition of powdered and sintered tungsten-basedhardmetals.This test method is not applicable to materialwhich will not oxidize readily at high temperatures in air,suchas tungsten/copper or tungsten/silver alloys.5.2 This test method specified lithium-borate compoundsfor the glass fusion material.However,numerous other choicesare available.These include other lithium-borate compounds,sodium carbonate and borate mixtures,and others.The meth-odology specified here is still applicable as long as the samefusion mixture is used for both standards and specimens.1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Productsand is the direct responsibility of Subcommit-tee B09.06 on Cemented Carbides.Current edition approved October 1,2012.Published October 2012.Originallyapproved in 1998.Last previous edition approved in 2007 as B890 07.DOI:10.1520/B0890-07R12.2For referenced 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.3CRC Press,Boca Raton,FL,1987.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.Interferences6.1 Errors in XRF-determined compositional values may beencountered due to X-ray enhancement and absorption effectsdependent on the elements present and the X-ray line beingmeasured for a specific element.This effect can be reduced bydetermination of correction factors using appropriate standardsand interelement correction routines,manual or computerized.6.2 Accuracy and precision of the analytical results obtainedfrom molybdenum-containing samples may be rendered unre-liable due to the sublimation and