ASTM B890-07(2012)
(Test Method)Standard Test Method for Determination of Metallic Constituents of Tungsten Alloys and Tungsten Hardmetals by X-Ray Fluorescence Spectrometry
Standard Test Method for Determination of Metallic Constituents of Tungsten Alloys and Tungsten Hardmetals by X-Ray Fluorescence Spectrometry
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/silver 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.
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. 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
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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: B890 − 07 (Reapproved 2012)
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 2.2 Handbook of Chemistry and Physics, 67th ed
1.1 This test method describes a procedure for the determi-
nationoftheconcentration,generallyreportedasmasspercent,
3. Terminology
of the metallic constituents of tungsten-based alloys and
3.1 For definitions of terms used in this test method, refer to
hardmetals utilizing wavelength dispersive X-ray fluorescence
Terminology E135.
spectrometry (XRF). This test method incorporates the prepa-
ration of standards using reagent grade metallic oxides,
4. Summary of Test Method
lithium-borate compounds, and fusion techniques. This test
4.1 A suite of standards which closely match the chemical
method details techniques for preparing representative speci-
mens of both powder and sintered tungsten-based material. content of the material to be analyzed are prepared using
reagent grade metallic oxides. Test samples are oxidized in a
This test method is accurate for a wide range of compositions,
and can be used for acceptance of material to grade specifica- high-temperature furnace open to air. Fused glass specimens
are prepared for these standards and for the test samples to be
tions.
analyzed. These specimens of oxidized tungsten or tungsten
1.2 This test method is applicable to mixtures of tungsten or
carbide alloys are irradiated with an energetic primary X-ray
tungsten carbide with additions of refractory metal carbides
beam. The intensity of the resultant secondary X-rays, charac-
and binder metals. Table 1 lists the most common elemental
teristicinenergy,foreachelementalconstituentismeasuredby
constituents and their concentration range. Note that many of
means of a suitable detector or combination of detectors after
these occur as metallic carbides.
diffraction by a Bragg spectrometer. The concentration of each
1.3 This standard does not purport to address all of the
constituent element is calculated by comparison with standard
safety concerns, if any, associated with its use. It is the
samples which closely match the chemical content of the
responsibility of the user of this standard to establish appro-
analyzed material.The calculation may be manual, incorporate
priate safety and health practices and determine the applica-
a calibration curve, or be performed by a computer program
bility of regulatory limitations prior to use.
which incorporates correction routines for X-ray absorption
and enhancement effects (see Guide E1361).
2. Referenced Documents
5. Significance and Use
2.1 ASTM Standards:
E135 Terminology Relating to Analytical Chemistry for
5.1 This test method allows the determination of the chemi-
Metals, Ores, and Related Materials
cal composition of powdered and sintered tungsten-based
E1361 Guide for Correction of Interelement Effects in
hardmetals. This test method is not applicable to material
X-Ray Spectrometric Analysis
which will not oxidize readily at high temperatures in air, such
as tungsten/copper or tungsten/silver alloys.
5.2 This test method specified lithium-borate compounds
This test method is under the jurisdiction of ASTM Committee B09 on Metal
for the glass fusion material. However, numerous other choices
Powders and Metal Powder Productsand is the direct responsibility of Subcommit-
are available. These include other lithium-borate compounds,
tee B09.06 on Cemented Carbides.
Current edition approved October 1, 2012. Published October 2012. Originally sodium carbonate and borate mixtures, and others. The meth-
approved in 1998. Last previous edition approved in 2007 as B890 – 07. DOI:
odology specified here is still applicable as long as the same
10.1520/B0890-07R12.
fusion mixture is used for both standards and specimens.
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. CRC Press, Boca Raton, FL, 1987.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B890 − 07 (2012)
TABLE 1 Elemental Constituents and Concentration Range
7.14 High-Temperature marking pen
Element Concentration, Mass %
7.15 Ceramic Mortar and Pestle
(minimum - maximum)
7.16 Tungsten Carbide Mortar and Pestle
Chromium (Cr) 0.05 - 5.0
Cobalt (Co) 0.05 - 40
7.17 Miniature Mixer, optional
Hafnium (Hf) 0.05 - 2.0
Iron (Fe) 0.05 - 2.0
Molybdenum (Mo) 0.05 - 5.0
8. Reagents and Materials
Nickel (Ni) 0.05 - 30
Niobium (Nb) 0.05 - 15 8.1 Purity of Reagents—Reagent grade chemicals shall be
Tantalum (Ta) 0.05 - 30
used in all tests. Unless otherwise indicated, it is intended that
Titanium (Ti) 0.05 - 30
all reagents conform to the specification of the Committee on
Vanadium (V) 0.05 - 2.0
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
6. Interferences
the determination.
6.1 Errors in XRF-determined compositional values may be
8.2 Di-lithiumtetraborate (Li B O ):Lithiummetaborate
encountered due to X-ray enhancement and absorption effects 2 4 7
(LiBO ), 66 + 34.
dependent on the elements present and the X-ray line being 2
measured for a specific element. This effect can be reduced by
8.3 Lithium Bromide (LiBr).
determination of correction factors using appropriate standards
8.4 Metallic Oxide Powder, highest oxidation state for
and interelement correction routines, manual or computerized.
elements of interest; that is Co O,Cr O,Fe O , HfO ,
3 4 2 3 3 4 2
6.2 Accuracyandprecisionoftheanalyticalresultsobtained
MoO,Nb O , NiO, Ta O,TiO,V O , and WO
3 2 5 2 5 2 2 5 3
from molybdenum-containing samples may be rendered unre-
Warning—Several of the metallic oxides used in this test
liable due to the sublimation and evaporation of molybdenum
method are highly toxic and possibly carcinogenic, such as
from the material during the oxidation step in specimen
Cr O , NiO, or V O . Extreme care should be used at all times
2 3 2 5
preparation.
when handling this material (especially V O ). All mixing of
2 5
standards should be performed in a fume hood. All of the
6.3 Incorporation of the fusion method of specimen prepa-
lithium compounds are water-soluble and therefore able to be
ration will:
absorbed into the body by inhalation and possibly by absorp-
6.3.1 Reduce the deleterious influence of particle size ef-
tion through the skin. This material should be weighed in a
fects experienced when analyzing powder materials by varying
fume hood.
particle size.
6.3.2 Reduce inhomogenieties within a sample.
8.5 Citric Acid (HO·C(COOH)(CH ·COOH) .
2 2
6.3.3 Improve penetration of X rays.
8.6 Silicic Acid (SiO ·xH 0).
2 2
6.3.4 Reduce interelement interferences by tungsten on all
other elements.
9. Specimen Preparation
9.1 Prepare specimens of the material to be analyzed by
7. Apparatus
oxidizing, weighing, and fusing starting powders, chips, or
7.1 X-Ray Fluorescence Wavelength Dispersive Spectrom-
crushed sintered hard metal samples.
eter
9.2 Place 3 to5gof powdered specimen in a labeled
7.2 Fluxer—An automated high-temperature mixing device
ceramic combustion boat. If a sintered sample is to be
capable of melting, mixing, and pouring a molten liquid
analyzed, then the sample must be crushed or pulverized into
specimen into a proper casting dish, is highly preferred
small pieces or chips must be produced by machining prior to
7.3 Analytical Balance, readability of 0.00001 g
placement in the combustion boat. To crush or pulverize a
sample, a tungsten carbide mortar and pestle should be used to
7.4 Toploading Balance, readability of 0.001 g
reduce the incidence of contamination.
7.5 Ordinary Laboratory Apparatus .
9.3 Oxidize the specimen in the heat zone of a high-
7.6 One Pt - 5 % Au Casting Dish (minimum)
temperature tube or muffle furnace open to the atmosphere at
7.7 One Pt - 5 % Au Crucible (minimum)
825 6 25°C. All specimens must be oxidized.
7.8 Platinum Tipped Tongs
9.4 When the specimen has been completely oxidized (4 to
6 h), remove from the furnace and allow to cool.
7.9 Weighing Paper
7.10 Chemical Spoon and Scoopula
Reagent Chemicals, American Chemical Society Specification, American
7.11 Ceramic Combustion Boat
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
7.12 High Temperature Tube or Muffle Furnace, open to the listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd,. Poole, Dorset, U.K., and the United States Pharmacopeia
atmosphere
and National Formulatory, U.S. Pharmaceutical Convention, Inc. (USPC),
7.13 Self-adhering Stickers, ⁄4 by 1 in. Rockvale, MD.
B890 − 07 (2012)
NOTE 1—Complete oxidation of a sintered magnetic tungsten hard
fromtheplatinumcastingdishwithverylighttapping,dissolve
metal sample can be checked by testing the cool oxidized chips with a
the specimen from the dish using a warm 2-volume percent
magnet.Ifanyofthechipsarestillmagnetic,recrushthesampleandplace
citricacidsolution.Prepareanewspecimeninaccordancewith
back in the furnace for further oxidation.
9.7-9.10.
9.5 Pour the specimen onto a clean sheet of paper or into a
Caution—Excessive prying or tapping of the crystallized
clean mortar and gently crush with a pestle.
specimen while it is in the dish will damage the platinum ware.
9.6 Transfer the specimen to a labeled specimen vial.
10. Standardization of Spectromete
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