ASTM B890-20

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: B890 − 07 (Reapproved 2012) B890 − 20
Standard Test Method for
Determination of Metallic Constituents of Tungsten Alloys
and Tungsten Hardmetals by X-Ray Fluorescence
Spectrometry
This standard is issued under the fixed designation B890; 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 describes a procedure for the determination of the concentration, generally reported as mass percent, of the
metallic constituents of tungsten-based alloys and hardmetals utilizing wavelength dispersive X-ray fluorescence spectrometry
(XRF). This test method incorporates the preparation of standards using reagent grade metallic oxides, lithium-borate compounds,
and fusion techniques. This test method details techniques for preparing representative specimens 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 specifications.
1.2 This test method is applicable to mixtures of tungsten or tungsten carbide with additions of refractory metal carbides and
binder metals. Table 1 lists the most common elemental constituents and their concentration range. Note that many of these occur
as metallic carbides.
1.3 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.
1.4 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:
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E1361 Guide for Correction of Interelement Effects in X-Ray Spectrometric Analysis
2.2 Handbook of Chemistry and Physics, 67th ed
3. Terminology
3.1 For definitions of terms used in this test method, refer to Terminology E135.
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 B09.06
on Cemented Carbides.
Current edition approved October 1, 2012Oct. 1, 2020. Published October 2012November 2020. Originally approved in 1998. Last previous edition approved in 20072012
as B890 – 07.B890 – 07(2012). DOI: 10.1520/B0890-07R12.10.1520/B0890-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B890 − 20
TABLE 1 Elemental Constituents and Concentration Range
Element Concentration, Mass %
(minimum - maximum)
Chromium (Cr) 0.05 - 5.0
Cobalt (Co) 0.05 - 40
Hafnium (Hf) 0.05 - 2.0
Iron (Fe) 0.05 - 2.0
Molybdenum (Mo) 0.05 - 5.0
Nickel (Ni) 0.05 - 30
Niobium (Nb) 0.05 - 15
Tantalum (Ta) 0.05 - 30
Titanium (Ti) 0.05 - 30
Vanadium (V) 0.05 - 2.0
4. Summary of Test Method
4.1 A suite of standards which closely match the chemical content of the material to be analyzed are prepared using reagent grade
metallic oxides. Test samples are oxidized in a high-temperature furnace open to air. Fused glass specimens are prepared for these
standards and for the test samples to be analyzed. These specimens of oxidized tungsten or tungsten carbide alloys are irradiated
with an energetic primary X-ray beam. The intensity of the resultant secondary X-rays, characteristic in energy, for each elemental
constituent is measured by means of a suitable detector or combination of detectors after diffraction by a Bragg spectrometer. The
concentration of each constituent element is calculated by comparison with standard samples which closely match the chemical
content of the analyzed material. The calculation may be manual, incorporate a calibration curve, or be performed by a computer
program which incorporates correction routines for X-ray absorption and enhancement effects (see Guide E1361).
5. Significance and Use
5.1 This test method allows the determination of the chemical composition of powdered and sintered tungsten-based hardmetals.
This test method is not applicable to material which will not oxidize readily at high temperatures in air, such as tungsten/copper
or tungsten/silvertungsten/copper, tungsten/silver alloys, or tungsten/cobalt-ruthenium alloys.
5.2 This test method specified lithium-borate compounds for the glass fusion material. However, numerous other choices are
available. These include other lithium-borate compounds, sodium carbonate and borate mixtures, and others. The methodology
specified here is still applicable as long as the same fusion mixture is used for both standards and specimens.
6. Interferences
6.1 Errors in XRF-determined compositional values may be encountered due to X-ray enhancement and absorption effects
dependent on the elements present and the X-ray line being measured for a specific element. This effect can be reduced by
determination of correction factors using appropriate standards and interelement correction routines, manual or computerized.
6.2 Accuracy and precision of the analytical results obtained from molybdenum-containing samples may be rendered unreliable
due to the sublimation and evaporation of molybdenum from the material during the oxidation step in specimen preparation.
6.3 Incorporation of the fusion method of specimen preparation will:
6.3.1 Reduce the deleterious influence of particle size effects experienced when analyzing powder materials by varying particle
size.
6.3.2 Reduce inhomogenieties within a sample.
6.3.3 Improve penetration of X rays.
6.3.4 Reduce interelement interferences by tungsten on all other elements.interferences.
7. Apparatus
7.1 X-Ray Fluorescence Wavelength Dispersive SpectrometerSpectrometer.
B890 − 20
7.2 Fluxer—An automated high-temperature mixing device capable of melting, mixing, and pouring a molten liquid specimen into
a proper casting dish, is highly preferredpreferred.
7.3 Analytical Balance, readability of 0.00001 g0.0001 g.
7.4 Toploading Balance, readability of 0.001 gg.
7.5 Ordinary Laboratory Apparatus . Apparatus.
7.6 One Pt - 5 % Au Casting Dish (minimum)(minimum).
7.7 One Pt - 5 % Au Crucible (minimum)(minimum).
7.8 Platinum Tipped TongsTongs.
7.9 Weighing PaperPaper.
7.10 Chemical Spoon and ScoopulaScoopula.
7.11 Ceramic or Quartz Combustion BoatBoat.
7.12 High Temperature Tube or Muffle Furnace, open to the atmosphereatmosphere.
7.13 Self-adhering Stickers, ⁄4 by 1 in.
7.14 High-Temperature marking pen
7.14 Ceramic Mortar and PestlePestle.
7.15 Tungsten Carbide Mortar and PestlePestle.
7.16 Miniature Mixer, optionaloptional.
8. Reagents and Materials
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specification of the Committee on Analytical Reagents of the American Chemical Society where 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 Di-lithiumtetraborate (Li B O ):Lithiummetaborate (LiBO ), 66 + 34.34 by mass percentage.
2 4 7 2
8.3 Lithium Bromide (LiBr).
8.4 Metallic Oxide Powder, highest oxidation state for elements of interest; that is Co O , Cr O , Fe O , HfO , MoO , Nb O ,
3 4 2 3 3 4 2 3 2 5
NiO, Ta O , TiO , V O , and WO
2 5 2 2 5 3
Reagent Chemicals, American Chemical Society Specification, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the
American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd,. Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulatory,
U.S. Pharmaceutical Convention, Inc. (USPC), Rockvale, MD.
B890 − 20
Warning—Several of the metallic oxides used in this test method are highly toxic and possibly carcinogenic, such as Cr O ,
2 3
NiO, or V O . Extreme care should be used at all times when handling this material (especially V O ). All mixing of standards
2 5 2 5
should be performed in a fume hood. All of the lithium compounds are water-soluble and therefore able to be absorbed into the
body by inhalation and possibly by absorption through the skin. This material should be weighed in a fume hood.
8.5 Citric Acid (HO·C(COOH)(CH ·COOH) ., used for cleaning purposes only.
2 2
8.6 Silicic Acid (SiO ·xH 0).
2 2
9. Specimen Preparation
9.1 Prepare specimens of the material to be analyzed by oxidizing, weighing, and fusing starting powders, chips, or crushed
sintered hard metal samples.
9.2 Place 3 to 5 g of powdered specimen in a labeled ceramic combustion boat. If a sintered sample is to be analyzed, then the
sample must be crushed or pulverized into small pieces or chips must be produced by machining prior to placement in the
combustion boat. To crush or pulverize a sample, a tungsten carbide mortar and pestle should be used to reduce the incidence of
contamination.
9.3 Oxidize the specimen in the heat zone of a high-temperature tube or muffle furnace open to the atmosphere at 825 6
25°C.25 °C. All specimens must be fully oxidized.
9.4 When the specimen has been completely oxidized (4 to 6 h), remove from the furnace and allow to cool.
NOTE 1—Complete oxidation of a sintered magnetic tungsten hard metal sample can be checked by testing the cool oxidized chips with a magnet. If any
of the chips aresample is still magnetic, recrush the sample and place back in the furnace for further oxidation.
9.5 Pour the specimen onto a clean sheet of paper or into a clean mortar and gently crush with a pestle.
9.6 Transfer the specimen to a labeled specimen vial.
9.7 In a fume hood, weigh out 15.000 6 0.001 g of the dilithium tetraborate: lithiummetaborate mixture, 1.5 6 0.001 g of the
silicic acid, and 0.200 6 0.001 g of LiBr and transfer to a clean sample vial. This mixture will be referred to as the “fusion
...