ASTM E2626-08
(Guide)Standard Guide for Spectrometric Analysis of Reactive and Refractory Metals
Standard Guide for Spectrometric Analysis of Reactive and Refractory Metals
SIGNIFICANCE AND USE
Test methods for chemical analysis of reactive and refractory metals are primarily intended to test such materials for compliance with compositional specifications. It is assumed that all who use this guide will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory under appropriate quality control practices such as those described in Guide E 882 and Practice E 2437, as well as in ISO 17025 and ISO Guide 32.
This guide is intended to aid analytical chemistry laboratories in the analysis of reactive and refractory metals and their alloys when no specific standard test methods are available. The principles incorporated in this practice can also be applied in laboratories that wish to validate and document non-standard test methods.
The analysis of reactive and refractory materials is typically performed by only a small number of laboratories. Few of these laboratories have analytical instrumentation in common for use in interlaboratory proficiency testing programs. This requires the use of within-laboratory developed test methods that vary between laboratories. It is intended that this practice will give general guidance to experienced personnel that will assist them in the development of a procedure that will meet their analytical objectives.
Practice E 2438 provides guidance for the development and documentation of an In-House Standard Operating Procedure (SOP).
SCOPE
1.1 This guide covers a variety of analytical techniques that have proven to be acceptable for the analysis of the reactive and refractory metals titanium, zirconium, niobium, hafnium, tantalum, molybdenum, tungsten, and vanadium.
1.2 The principles and techniques in this guide can be used by ISO 17025 compliant laboratories that need to implement other performance-based test methods or need to document and validate extensions of standard test methods, or non-standard test methods.
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.
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Designation:E2626–08
Standard Guide for
Spectrometric Analysis of Reactive and Refractory Metals
This standard is issued under the fixed designation E2626; 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 E1479 Practice for Describing and Specifying Inductively-
Coupled Plasma Atomic Emission Spectrometers
1.1 This guide covers a variety of analytical techniques that
E1552 Test Method for Determining Hafnium in Zirconium
have proven to be acceptable for the analysis of the reactive
and ZirconiumAlloys By Direct Current Plasma—Atomic
and refractory metals titanium, zirconium, niobium, hafnium,
Emission Spectrometry
tantalum, molybdenum, tungsten, and vanadium.
E1601 Practice for Conducting an Interlaboratory Study to
1.2 The principles and techniques in this guide can be used
Evaluate the Performance of an Analytical Method
by ISO 17025 compliant laboratories that need to implement
E1621 Guide for X-Ray Emission Spectrometric Analysis
otherperformance-basedtestmethodsorneedtodocumentand
E1770 Practice for Optimization of Electrothermal Atomic
validate extensions of standard test methods, or non-standard
Absorption Spectrometric Equipment
test methods.
E2371 Test Method for Analysis of Titanium and Titanium
1.3 The values stated in SI units are to be regarded as
Alloys by Atomic Emission Plasma Spectrometry
standard. No other units of measurement are included in this
E2437 Practice for Designing and Validating Performance-
standard.
Based Test Methods for the Analysis of Metals, Ores, and
1.4 This standard does not purport to address all of the
Related Materials
safety concerns, if any, associated with its use. It is the
E2438 Practice for Implementing Standard Performance
responsibility of the user of this standard to establish appro-
Based Test Methods for the Analysis of Metals, Ores, and
priate safety and health practices and determine the applica-
Related Materials
bility of regulatory limitations prior to use.
2.2 ISO Standards:
2. Referenced Documents ISO 17025 General Requirements for the Competence of
Testing and Calibration Laboratories
2.1 ASTM Standards:
ISO Guide 32 Calibration in Analytical Chemistry and Use
D1193 Specification for Reagent Water
of Certified Reference Materials
E50 Practices for Apparatus, Reagents, and Safety Consid-
erations for Chemical Analysis of Metals, Ores, and
3. Terminology
Related Materials
3.1 Definitions—For definitions of terms used in this guide,
E135 Terminology Relating to Analytical Chemistry for
refer to Terminology E135.
Metals, Ores, and Related Materials
3.2 Definitions of Terms Specific to This Standard:
E539 Test Method for X-Ray Fluorescence Spectrometric
3.2.1 reactive metal, n—a metal, such as titanium or zirco-
Analysis of 6Al-4V Titanium Alloy
nium, that readily reacts with the environment. It has a strong
E882 Guide for Accountability and Quality Control in the
affinity for oxygen and nitrogen and forms very stable com-
Chemical Analysis Laboratory
pounds that passivate in thin layers. When the reactive coating
E1097 Guide for Direct Current Plasma-Atomic Emission
is damaged, it self heals by reaction with the atmosphere.
Spectrometry Analysis
3.2.2 refractory metal, n—a metal, such as hafnium, molyb-
E1184 Practice for Electrothermal (Graphite Furnace)
denum, niobium, tantalum, vanadium, or tungsten, character-
Atomic Absorption Analysis
ized by very high melting points, above about 1900 °C, that
oxidizes at temperatures far below its melting point.
This guide is under the jurisdiction of ASTM Committee E01 on Analytical 4. Significance and Use
Chemistry for Metals, Ores and Related Materials and is the direct responsibility of
4.1 Test methods for chemical analysis of reactive and
Subcommittee E01.06 on Ti, Zr, W, Mo, Ta, Nb, Hf, Re.
refractory metals are primarily intended to test such materials
Current edition approved June 15, 2008. Published July 2008. DOI: 10.1520/
E2626-08.
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 Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2626–08
forcompliancewithcompositionalspecifications.Itisassumed 6.2 Atomic Emission Spectrometry (AES)—This technique
that all who use this guide will be trained analysts capable of has historically been the main means of analysis for these
performing common laboratory procedures skillfully and metals. Analysis by the techniques described in this section is
safely. It is expected that work will be performed in a properly based upon the fact that each vaporized element, when suitably
equippedlaboratoryunderappropriatequalitycontrolpractices
excited by an arc, spark, plasma, or other means, is made to
such as those described in Guide E882 and Practice E2437,as emit its characteristic spectrum. The radiation thus emitted
well as in ISO 17025 and ISO Guide 32.
passes into a spectrometer where it is resolved into its
4.2 This guide is intended to aid analytical chemistry component wavelengths and recorded by various means as a
laboratories in the analysis of reactive and refractory metals
definite pattern. The position of the spectral information
and their alloys when no specific standard test methods are indicates QUALITATIVELY which elements are present. The
available. The principles incorporated in this practice can also
intensity determines QUANTITATIVELY the amount of each
be applied in laboratories that wish to validate and document
element in the sample when compared to intensities obtained
non-standard test methods.
by using calibration materials. Calibration materials can be
4.3 The analysis of reactive and refractory materials is
reference materials or industry acceptable analyzed specimens.
typically performed by only a small number of laboratories.
6.2.1 Arc/Spark Spectrometry (AS-AES)—Instruments uti-
Few of these laboratories have analytical instrumentation in
lizing photographic film or plates were the mainstay for many
common for use in interlaboratory proficiency testing pro-
years until parts and supplies became very difficult, if not
grams. This requires the use of within-laboratory developed
impossible,toobtain.Electronicread-outarc/sparkinstruments
test methods that vary between laboratories. It is intended that
arestillusedbyanumberoflaboratories.Theprimaryproblem
this practice will give general guidance to experienced person-
with arc/spark is the unavailability of solid reference materials
nel that will assist them in the development of a procedure that
for calibration. Metallurgical history and surface grain size
will meet their analytical objectives.
effects can become an issue. However, if proper calibration
4.4 Practice E2438 provides guidance for the development
materials were available, the majority of the necessary ele-
and documentation of an In-House Standard Operating Proce-
ments in a typical material specification could be analyzed.
dure (SOP).
6.2.2 Direct Current Plasma Atomic Emission Spectrometry
(DCP-AES)—Since DCP-AES analysis, like atomic absorp-
5. Hazards
tion, Inductively Coupled PlasmaAtomic Emission Spectrom-
5.1 The dissolution of these metals usually requires the use
etry (ICP-AES) (see 6.2.3), and Inductively Coupled Plasma-
of hydrofluoric acid. Read and follow label precautions and
Mass Spectrometry (ICP-MS) (see 6.2.4), relies on sample
mandatory safety data sheet (MSDS) information, and refer to
dissolution, the major difficulties with reference materials for
Practices E50.
calibration with can be overcome by the techniques discussed
5.2 Fine turnings, chips, or powder require more water to
in 9.4. One of the main positive attributes of this technique is
moderate the reaction rate. If the metal is solid chunks rather
the high resolution available due to the Echelle grating. The
than finely divided, the dissolution will be much slower and
highly complex spectra of reactive and refractory metals
require less water. It will also require additional acid to
require an instrument with good spectral resolving power in
complete the dissolution. See Specification D1193 for reagent
order to find interference-free wavelengths.The DCP-AES has
water specifications.
a rugged sample introduction system that lends itself well to
5.3 Fine turnings or powder of hafnium, titanium, and
the analysis of materials that have been dissolved in acids such
zirconium are pyrophoric. Observe the proper precautions.
as hydrofluoric, nitric, and hydrochloric acids. In most cases,
6. Test Methods
due to the nature of the source design, the DCP-AES does not
achieve the detection limits or the precision of an Inductively
6.1 AtomicAbsorption Spectrometry (AAS)—Thistechnique
Coupled Plasma (ICP) source. In some cases, however, its
isapplicabletoelementsthatcanbedissolvedandplacedinthe
significantly superior resolving power may allow it to out-
vapor state (flame or flameless) as ground state atoms. Radia-
perform an ICP that utilizes a conventional ruled grating. The
tion from a hollow cathode light source emits the spectrum of
corrosion resistant nature of the sample introduction system
theelementtobeanalyzed,whichisthenpassedthroughvapor
and jet materials on DCP-AES has allowed it to be very
containing the element to be analyzed, and into a monochro-
capable for the analysis of silicon in a hydrofluoric acid
matorsetforradiationcharacteristicoftheelement.Thedegree
solution. DCP-AES is unable to achieve the necessary detec-
of absorption is measured, and is proportional to the amount of
tion limits for elements such as boron and cadmium in a
theparticularelementpresent.Analysisismadebycomparison
zirconium sample at the levels required by most specifications.
to reference materials. Lists of elements that can be deter-
Test Method E1552 gives details for the analysis of hafnium in
mined,sensitivities,wavelengths,andoperatingparametersare
zirconium and zirconium alloys using the DCP-AES technique
provided by the instrument manufacturers. Due to the require-
and Test Method E2371 describes the analysis of titanium and
ments of the materials specifications, theAAS detection limits
titanium alloys. Guide E1097 discusses the technique in more
for many elements will not be low enough for the use of this
general terms.
technique. AAS has been utilized for the analysis of iron,
chromium, nickel, and tin in zirconium alloys and for the 6.2.3 Inductively Coupled Plasma Atomic Emission Spec-
determination of iron and zirconium in hafnium. Practices trometry (ICP-AES)—Practice E1479 describes the compo-
E1184 and E1770 provide further details. nents of an ICP-AES that are basic to its operation and to the
E2626–08
qualityofitsperformance.ICP-AESandICP-MSrepresentthe set of homogeneous, solid reference materials limits the use of
instruments most commonly used for the analysis of reactive this technique. The low detection limit requirements for many
and refractory metals. These solution-based techniques of the required elements in these materials will not be achieved
complement each other to provide a reliable means of analysis by this technique. The analysis of iron, chromium, nickel, and
of reactive and refractory metals. Care must always be taken to tin in zirconium alloys and zirconium in hafnium have been
avoid serious spectral interferences due to the line-rich nature demonstrated to work well by X-ray. Test Method E539 and
of reactive and refractory metals. The advent of solid-state Guide E1621 give valuable guidance.
detectors has provided much flexibility in the selection of
wavelengths. Section 8.3 gives guidance in wavelength selec- 7. Calibration
tion. Test Method E2371 gives details for the analysis of
7.1 Setuptheinstrumentforcalibrationasrecommendedby
titanium and titanium alloys, while Practice E1479 discusses
the manufacturer. The publications listed in Section 2, as well
the techniques in more general terms.
as in texts, the analytical literature, and other standards
6.2.4 Inductively Coupled Plasma-Mass Spectrometry (ICP-
organizations, will also provide valuable guidance.
MS)—This technique is distinguished from ICP-AES by the
detection system used to analyze the species excited by a 8. Interferences
plasma. A mass spectrometer is utilized in this case. Much of
8.1 Guide E1097, Practice E1184, Practice E1479, Guide
the information in Practice E1479 is applicable to ICP-MS.
E1621, and Practice E1770 describe some of the interferences
Thistechniqueiscapableofanalyzingthemajorityofthemetal
encountered during analysis. The user is responsible for
elements necessary to satisfy the material specifications for
ensuring the absence of, or compensating for interferences that
reactive and refractory metals. The high sensitivity of ICP-MS
may bias test results obtained using their standard operating
may require significant dilution of the sample solution in order
procedures.
to analyze elements at concentrations above 0.1 %, by mass.
8.2 The physical interferences resulting from variations in
6.3 Glow Discharge Spectrometry—The issue mentioned
sample and calibration solution aerosol transport rates may be
above in securing solid reference materials is a concern that
compensated for by the use of an internal standard in some
must be addressed with this technique. Glow Discharge instru-
techniques.
mentation is normally divided into two types of instrumenta-
8.3 Table 1 lists wavelengths that have been used to analyze
tion.
thelistedelementsinthegivenmetalsandaresuggestedforthe
6.3.1 Glow Discharge-Mass Spectrometry (GD-MS)—In userofatomicemissionspectrometers.Duetotheresolutionof
this technique, the surface of a solid sample is sputtered with individual instruments, confirmation of these suggestions will
be required. Depending on the specific spectrometer, other
argongas.Ionizedspeciesarethensubjectedtohigh-resolution
mass spectrometric analysis.This results in the high sensitivity wavelengths will be found to be applicable.
analysis of all elements in the periodic table, except hydrogen
at the trace level. GD-MS has been used for the multi-element 9. Reference Materials
survey analysis for these metals included in the scope of this
9.1 Standard Reference Material (SR
...
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