ASTM E1938 - 13 (2018)

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Designation: E1938 −13 (Reapproved 2018)
Standard Test Method for
Determination of Titanium in Nickel Alloys by
Diantipyrylmethane Spectrophotometry
1
This standard is issued under the ﬁxed designation E1938; 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 covers the determination of titanium in
nickel alloys in the range 0.3 % to 5.0 %. With appropriate
reference materials, the test method may be extended down to
0.05 %.
1.2 Molybdenum, if present, may cause a high bias to the
extent of 0.001 % titanium for every 1 % molybdenum.
1.3 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
standard.
1.4 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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
For speciﬁc hazards associated with the use of this test method,
see Practices E50.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
E29 Practice for Using Signiﬁcant Digits in Test Data to
Determine Conformance with Speciﬁcations
E50 Practices for Apparatus, Reagents, and Safety Consid-
erations for Chemical Analysis of Metals, Ores, and
Related Materials
E135 Terminology Relating to Analytical Chemistry for
Metals, Ores, and Related Materials
E882 Guide for Accountability and Quality Control in the
Chemical Analysis Laboratory
E1601 Practice for Conducting an Interlaboratory Study to
Evaluate the Performance of an Analytical Method
2.2 ISO Standards:
3
ISO 5725:1986 Precision of Test Methods—Determination
of Repeatability and Reproducibility for a Standard Test
Method by Inter-Laboratory Tests
ISO 11433:1993(E) Nickel Alloys—Determination of Tita-
nium Content—Diantipyrylmethane Molecular Absorp-
tion Spectrometric Method
3. Terminology
3.1 Deﬁnitions—For deﬁnitions of terms used in this test
method, refer to Terminology E135.
4. Summary of Test Method
4.1 This test sample is dissolved in a mixture of HCl and
HNO
3
. The solution is evaporated to fumes of H
2
SO
4
to
remove the HCl and HNO
3
. Color is developed with
diantipyrylmethane, and the absorbance is measured at
390 nm.
5. Signiﬁcance and Use
5.1 This test method is used for the determination of
titanium in nickel alloy samples by molecular absorption
spectrometry to check compliance with compositional speciﬁ-
cations. It is assumed that all who use the procedure will be
trained analysts capable of performing common laboratory
procedures skillfully and safely. It is expected that the work
will be performed in a properly equipped laboratory and that
proper waste disposal procedures will be followed. Appropriate
quality control practices must be followed such as those
described in Guide E882.
6. Apparatus
6.1 Spectrophotometer, capable of measuring absorbance at
a wavelength of 390 nm.
1
This test method is under the jurisdiction of ASTM Committee E01 on
Analytical Chemistry for Metals, Ores, and Related Materials and is the direct
responsibility of Subcommittee E01.08 on Ni and Co and High Temperature Alloys.
Current edition approved Oct. 1, 2018. Published November 2018. Originally
approved in 1997. Last previous edition approved in 2013 as E1938 – 13. DOI:
10.1520/E1938-13R18.
2
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.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
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
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.
1
 

6.2 Cells, to ﬁt spectrophotometer, having an optical path of

1 cm.

NOTE 1—Cells having other dimensions can be used, provided suitable

adjustments can be made in the amount of sample and reagents used.

7. Reagents

7.1 Purity and Concentration of Reagents—The purity and

concentration of common chemical reagents and water shall

conform to Practices E50. The reagents should be free of or

contain only minimal amounts (< 0.1 µg ⁄g) of titanium.

7.2 Potassium Hydrogen Sulfate (KHSO

7.3 Ascorbic Acid Solution—Dissolve 20 g of ascorbic acid

) in water, dilute to 200 mL, and mix.

7.4 Oxalic Acid Solution—Dissolve 10 g of oxalic acid

dihydrate [(COOH)

O] in water, dilute to 200 mL, and

mix.

7.5 Diantipyrylmethane Solution—Dissolve 4 g of dian-

tipyrylmethane monohydrate (C

O) in water con-

taining 25 mL HCl (1 + 1). Dilute to 200 mL and mix.

7.6 Sodium Chloride Solution—Dissolve 117 g of sodium

chloride (NaCl) in water, dilute to 500 mL, and mix.

7.7 Titanium Stock Calibration Solution (200 µg ⁄mL Ti)—

Dissolve 0.739 g of potassium titanyl oxalate dihydrate

TiO(C

)

O] in water. Add 50 mL of H

(1+1)

and evaporate to dense fumes. Cool, dilute, and transfer the

room temperature solution to a 500-mL volumetric ﬂask.

Dilute to the mark and mix.

7.7.1 Alternative Preparation:Transfer 0.1000 g of titanium

metal (purity: 99.9 % minimum) weighed to within 60.2 mg

to a 500-mL glass volumetric ﬂask. Add 50 mL of

(1 + 3) and dissolve over low heat. Oxidize the titanium

by adding HNO

dropwise until the blue color is just dis-

charged (avoid excess HNO

which will cause the titanium to

precipitate). Cool to room temperature and dilute to volume

with H

(1 + 9).

7.8 Titanium Calibration Solution (25 µg ⁄mL Ti)—Transfer

25.0 mL of the titanium stock calibration solution to a 200-mL

volumetric ﬂask. Add 20 mL of H

(1 + 1). Cool the

solution to room temperature, dilute to the mark, and mix.

8. Sampling and Sample Preparation

8.1 Sampling shall be done by normal procedures agreed

upon between the parties, or in the event of a dispute,

according to the relevant standard, if one is available.

8.2 The laboratory sample is normally in the form of

millings or drillings and no further preparation of the sample is

necessary.

8.3 If it is suspected that the laboratory sample is contami-

nated with oil or grease from the milling or drilling operation,

it shall be cleaned by washing it with high purity acetone, or

other appropriate solvent, and drying in air.

8.4 If the sample contains particles or pieces of widely

varying sizes, the test sample should be obtained by riffling.

9. Procedure

9.1 Preparation of Test Solution:

9.1.1 Test Portion—Weigh the test portion of the sample in

accordance with Table 1.

9.1.2 Dissolution of Test Portion—Transfer the test portion

to a 125-mL Erlenmeyer ﬂask and add 10 mL of HC1 and 3 mL

of HNO

. Apply sufficient heat to initiate and maintain the

reaction until dissolution is complete. If the alloy resists

dissolution, some adjustment in the acid mixture may be

required. Add HC1 in 1-mL increments and continue heating to

dissolve the test portion.

9.1.3 Preparation of Final Test Solution:

9.1.3.1 Add 7 mL of H

(1 + 1) and evaporate the

solution until dense white fumes appear. Cool the contents and

proceed as directed in 9.1.3.2 or 9.1.3.3, depending on whether

tantalum is present in the sample or not.

9.1.3.2 In the absence of tantalum, add 20 mL of oxalic acid

solution and heat to dissolve the salts. Cool the solution and, in

tungsten free alloys, proceed as directed in 9.1.4. If the alloy

contains tungsten, add sufficient ammonium hydroxide to make

the solution alkaline. Boil the solution until the tungstic acid is

dissolved. Cool the solution and re-acidify by adding 20 mL of

HC1. Cool the solution and proceed as directed in 9.1.4.

9.1.3.3 In the presence of tantalum, add 30 mL of water,

heat to dissolve the salts and cool again. Filter the solution

through a tightly packed ﬁlter pulp pad. Wash the precipitate

with warm water. Retain the ﬁltrate. Transfer the pad and

precipitate to a platinum crucible, ignite at 800 °C, and cool.

Add 1 g of potassium pyrosulfate, cover the crucible with a

platinum lid and fuse carefully over a ﬂame. Cool and transfer

the crucible to a 150-mL beaker containing 20 mL of the oxalic

acid solution. Heat carefully until the melt is dissolved. Wash

and remove the platinum crucible. Combine the oxalate solu-

tion with the original ﬁltrate and proceed as directed in 9.1.4.

9.1.4 Dilutions:

9.1.4.1 Dilution for Less Than 1 % Titanium—Transfer the

test solution (see 9.1.3.2 or 9.1.3.3) to a 100-mL volumetric

ﬂask, dilute to the mark, and mix.

9.1.4.2 Dilution for 1 % to 5 % Titanium—Transfer the test

solution (see 9.1.3.2 or 9.1.3.3) to a 250-mL volumetric ﬂask,

dilute to the mark, and mix.

9.2 Color Development:

9.2.1 With a pipet, transfer 5.0-mL aliquots of the test

solution to each of two 50-mL volumetric ﬂasks.

9.2.2 Add 5.0 mL of HC1 (1 + 1), 5.0 mL of ascorbic acid

solution and 20.0 mL of NaCl solution to both volumetric

ﬂasks. Mix the solutions and allow to stand for a few minutes.

9.2.3 Add 10.0 mL of diantipyrylmethane solution to one of

the volumetric ﬂasks.

9.2.4 Dilute both ﬂasks to the mark, mix, and allow to stand

for 40 min.

TABLE 1 Mass of Sample to be Taken

Expected Ti Content,

Mass of Test Portion,

0.3 to 3.0 0.19 to 0.21

3.0 to 5.0 0.09 to 0.11

E1938 − 13 (2018)

9.3 Spectrophotometric Measurement:

9.3.1 Using a 1-cm cell, measure the absorbance of both

solutions against water as the reference at a wavelength of

390 nm with the spectrophotometer.

9.3.2 Subtract the background absorbance of the test solu-

tion from the absorbance of the test solution containing the

diantipyrylmethane complex.

9.4 Blank Test—Perform a blank test in parallel with the

determination following the same procedure and using the

same quantities of reagents.

9.5 Calibration:

9.5.1 Using a microburette, transfer (0, 1.0, 2.0, 3.0, 4.0 and

5.0) mL of the titanium calibration solution to a series of

50-mL volumetric ﬂasks.

9.5.2 Add HC1 (1 + 1), ascorbic acid and NaCl solution to

each of the volumetric ﬂasks. Mix the solutions and allow to

stand for a few minutes.

9.5.3 Add 10.0 mL of diantipyrylemethane solution to each

of the solutions, dilute to the marks, and mix. Allow to stand

for 40 min. This series corresponds to (0, 0.5, 1.0, 1.5, 2, and

2.5) µg titanium per millilitre.

9.5.4 Measure the absorbance of the calibration solutions as

described in 9.3. Subtract the measured absorbance of the

0 µg ⁄mL calibration solution from the absorbance values of the

remaining calibration solutions.

9.5.5 Plot the corrected absorbance values against the re-

spective concentrations of titanium, in micrograms per

millilitre, in the calibration solutions.

9.6 Number of Determinations—Perform the determinations

at least in duplicate.

9.7 Check Test, The performance of the test method may be

checked by analyzing, in parallel with the determinations and

following the same procedure, one or more samples of the

same type alloy whose titanium content is known.

10. Calculation

10.1 Determine the concentration of the titanium in the test

solutions and the blank by means of the calibration graph.

10.2 Calculate the titanium content C

, expressed as a

percentage by mass of the test portion using the formula:

A2B

/5D(1)

where:

A= the titanium concentration in µg/mL of the test solution,

B= the titanium concentration in µg/mL of the blank test

solution,

C= the ﬁnal dilution volume in mL of the test solution, and

D= the sample mass in g.

10.3 Rounding of test results obtained using this test method

shall be performed as directed in Practice E29, Rounding

Method, unless an alternative rounding method is speciﬁed by

the customer or applicable material speciﬁcations.

11. Precision and Bias

11.1 Precision—Eleven laboratories in four countries par-

ticipated in testing this method under the auspices of ISO/

TC155/SC4 in the late 1980s and published as

ISO 11433:1993(E). Four samples of nominal composition

given in Table 2 were tested to obtain the statistical

information, as evaluated by ISO 5725:1986 and equivalent to

Practice E1601, summarized in Table 3. Precision may be

judged by examination of these data.

11.2 Bias—No information on the accuracy of this test

method is known because accepted reference standards were

not used in the interlaboratory study. The user of this test

method is encouraged to use accepted reference materials, if

available, to determine the accuracy of this test method as it

applies in a speciﬁc laboratory.

12. Keywords

12.1 molecular absorption spectrometry; nickel alloy; spec-

trophotometric; titanium content

Supporting data have been ﬁled at ASTM International Headquarters and may

be obtained by requesting Research Report RR:E01-1025.

TABLE 2 Nominal Composition of Test Samples (in %)

Test

Material

Al Co Cr Fe Hf Mo Nb Ta Ti W Ni

RE-2 0.5 0.5 20 18 3 5 1.0 Balance

RE-1 5.5 10 9 1.6 2.6 1.5 10 Balance

RE-3 1.9 19 22 1 1.4 3.7 2 Balance

RE-4 3.0 10 14 4 5.0 4 Balance

E1938 − 13 (2018)

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摘要：

获取关于 ASTM E1938 - 13 (2018) 标准规范的最新权威解读，该标准全称为《金属材料热电功率测定的试验方法》。本文件详细规定了如何通过测量材料两端温差所产生的热电动势（即塞贝克效应）来评估金属与合金的微观结构变化、相变过程及材料退化程度。该测试方法尤其适用于在核工业、电力行业及材料科学研究中，对铁素体、马氏体及奥氏体不锈钢等材料进行非破坏性的快速筛选与老化状态监测。标准版本 E1938-13 (2018) 整合并确认了原有的技术要点，确保了在不同实验室条件下测试结果的可重复性与

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