ASTM E1938-97
(Test Method)Standard Test Method for Determination of Titanium in Nickel Alloys by Diantipyrylmethane Molecular Absorption Spectrometric Method
Standard Test Method for Determination of Titanium in Nickel Alloys by Diantipyrylmethane Molecular Absorption Spectrometric Method
SCOPE
1.1 This test method covers the determination of titanium in nickel alloys in the 0.3 through 5.0% range. With appropriate reference materials the test method may be extended down to 0.05%.
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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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Designation: E 1938 – 97
Standard Test Method for
Determination of Titanium in Nickel Alloys by
Diantipyrylmethane Molecular Absorption Spectrometric
Method
This standard is issued under the fixed designation E 1938; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope Titanium Content - Diantipyrylmethane Molecular Ab-
sorption Spectrometric Method
1.1 This test method covers the determination of titanium in
nickel alloys in the 0.3 through 5.0 % range. With appropriate
3. Summary of Test Method
reference materials the test method may be extended down to
3.1 This sample is dissolved in a mixture of hydrochloric
0.05 %.
and nitric acid. The solution is evaporated to sulfuric acid
1.2 Molybdenum, if present, may cause a high bias to the
fumes to remove the hydrochloric and nitric acids. Color is
extent of 0.001 % Ti for every 1 % Mo.
developed with diantipyrylmethane, and the absorbance is
1.3 This standard does not purport to address all of the
measured at 390 nm.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Significance and Use
priate safety and health practices and determine the applica-
4.1 This practice is used for the analysis of nickel and nickel
bility of regulatory limitations prior to use. For specific hazards
base alloy samples by molecular absorption spectrometry to
associated with the use of this test method see Practices E 50.
check compliance with compositional specifications. It is
2. Referenced Documents assumed that all who use the procedure will be trained analysts
capable of performing common laboratory procedures skill-
2.1 ASTM Standards:
fully and safely. It is expected that the work will be performed
E 50 Practices for Apparatus, Reagents, and Safety Precau-
2 in a properly equipped laboratory and that proper waste
tions for Chemical Analysis of Metals
disposal procedures will be followed. Appropriate quality
E 882 Guide for Accountability and Quality Control in the
3 control practices must be followed such as those described in
Chemical Analysis Laboratory
Guide E 882.
E 1452 Practice for Preparation of Calibration Solutions for
Spectrophotometric and for Spectroscopic Atomic Analy-
5. Apparatus
sis
5.1 Spectrophotometer, capable of measuring absorbance at
E 1601 Practice for Conducting an Interlaboratory Study to
3 a wavelength of 390 nm.
Evaluate the Performance of an Analytical Method
5.2 Cells, to fit spectrophotometer, having an optical path of
2.2 ISO Standards:
1 cm.
ISO 5725:1986 - Precision of Test Methods – Determina-
tion of Repeatability and Reproducibility for a Standard
NOTE 1—Cells having other dimensions can be used, provided suitable
adjustments can be made in the amount of sample and reagents used.
Test Method by Inter-Laboratory Tests
ISO 11433:1993(E) - Nickel Alloys - Determination of
6. Reagents
6.1 Purity and Concentration of Reagents—The purity and
This test method is under the jurisdiction of ASTM Committee E-1 on
concentration of common chemical reagents shall conform to
Analytical Chemistry of Metals, Ores and Related Materials, and is the direct
Practices E 50. The reagents should be free of or contain only
responsibility of Subcommittee E01.08 on Nickel, Cobalt and High Temperature
minimal amounts (< 0.1 μg/g) of titanium. Calibration solu-
Alloys.
Current edition approved Dec. 10, 1997. Published August 1998.
tions shall be prepared in accordance with Practice E 1452.
Annual Book of ASTM Standards, Vol 03.05.
6.2 Potassium Hydrogen Sulfate (KHSO ).
Annual Book of ASTM Standards, Vol 03.06.
4 6.3 Ascorbic Acid Solution—Dissolve 20 g ascorbic acid
Available from American National Standards Institute, 11 West 42nd Street,
(C H O ) in water, dilute to 200 mL and mix.
New York, NY 10036.
6 8 6
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E1938–97
6.4 Oxalic Acid Solution—Dissolve 10 g of oxalic acid required. Add HC1 in 1-mL increments and continue heating to
dihydrate [(COOH) 2H O] in water and dilute to 200 mL and dissolve the test portion.
2 2
mix.
9.1.3 Preparation of Final Test Solution
6.5 Diantipyrylmethane Solution—Dissolve4gof dian-
9.1.3.1 Add 7 mL H SO (1+1) and evaporate the solution
2 4
tipyrylmethane monohydrate (C H N O H O) in water con-
until dense white fumes appear. Cool the contents and proceed
23 24 4 2 2
taining 25 mL hydrochloric acid (1+1). Dilute with water to
as directed in 9.1.3.2 or 9.1.3.3, depending on whether tanta-
200 mL to mix.
lum is present in the sample or not.
6.6 Sodium Chloride Solution—Dissolve 117 g of sodium
9.1.3.2 In the absence of tantalum, add 20 mL oxalic acid
chloride (NaCl) in water and dilute to 500 mL and mix.
solution and heat to dissolve the salts. Cool the solution and, in
6.7 Titanium Stock Calibration Solution—Dissolve 0.739 g
tungsten free alloys, proceed as directed in 9.1.4. If the alloy
of potassium titanyl oxalate dihydrate [K TiO(C O ) 2H O] in
2 2 4 2 2 contains tungsten, add sufficient ammonium hydroxide to make
water. Add 50 mL of sulfuric acid (1+1) and evaporate to dense
the solution alkaline. Boil the solution until the tungstic acid is
fumes. Cool and dilute with water. Cool and transfer the room
dissolved. Cool the solution and reacidify by adding 20 mL of
temperature solution to a 500 mL volumetric flask. Dilute to
HC1. Cool the solution and proceed as directed in 9.1.4.
the mark with water and mix.
9.1.3.3 In the presence of tantalum add 30 mL of water, heat
6.8 Titanium Calibration Solution—Transfer 25.0 mL of the
to dissolve the salts and cool again. Filter the solution through
titanium stock calibration solution (see 6.7) to a 200 mL
a tightly packed filter pulp pad. Wash the precipitate with warm
volumetric flask. Add 20 mL of sulfuric acid (1+1). Cool the
water. Retain the filtrate. Transfer the pad and precipitate to a
solution to room temperature, dilute to the mark with water and
platinum crucible, ignite at 800°C, and cool. Add1gof
mix.
potassium pyrosulfate, cover the crucible with a platinum lid
and fuse carefully over a flame. Cool and transfer the crucible
7. Sampling and Sample Preparation
to a 150-mL beaker containing 20 mL of the oxalic acid
solution. Heat carefully until the melt is dissolved. Wash and
7.1 The sampling shall be carried out by normal procedures
remove the platinum crucible. Combine the oxalate solution
agreed upon between the parties, or in the event of a dispute,
with the original filtrate and proceed as directed in 9.1.4.
according to the relevant standard, if one is available.
7.2 The laboratory sample is normally in the form of 9.1.4 Dilutions:
millings or drillings and no further preparation of the sample is 9.1.4.1 Dilution for Less Than 1 % Titanium—Transfer the
necessary. test solution (see 9.1.3.1 or 9.1.3.2) to a 100-mL volumetric
7.3 If it is suspected that the laborat
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