1、Designation: E 1938 08Standard Test Method forDetermination of Titanium in Nickel Alloys byDiantipyrylmethane Molecular Absorption Spectrometry1This standard is issued under the fixed designation E 1938; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of titanium innickel alloys in the range 0.
3、3 % to 5.0 %. With appropriatereference materials, the test method may be extended down to0.05 %.1.2 Molybdenum, if present, may cause a high bias to theextent of 0.001 % titanium for every 1 % molybdenum.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement
4、are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations
5、 prior to use. For specific hazardsassociated with the use of this test method, see Practices E50.2. Referenced Documents2.1 ASTM Standards:2E50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated MaterialsE 135 Terminology Relating to Anal
6、ytical Chemistry forMetals, Ores, and Related MaterialsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method2.2 ISO Standards:3ISO 5725:1986 Precision of Test Met
7、hodsDeterminationof Repeatability and Reproducibility for a Standard TestMethod by Inter-Laboratory TestsISO 11433:1993(E) Nickel AlloysDetermination of Tita-nium ContentDiantipyrylmethane Molecular Absorp-tion Spectrometric Method3. Terminology3.1 DefinitionsFor definitions of terms used in this te
8、stmethod, refer to Terminology E 135.4. Summary of Test Method4.1 This test sample is dissolved in a mixture of HCl andHNO3. The solution is evaporated to fumes of H2SO4toremove the HCl and HNO3. Color is developed with dian-tipyrylmethane, and the absorbance is measured at 390 nm.5. Significance an
9、d Use5.1 This test method is used for the determination oftitanium in nickel alloy samples by molecular absorptionspectrometry to check compliance with compositional specifi-cations. It is assumed that all who use the procedure will betrained analysts capable of performing common laboratoryprocedure
10、s skillfully and safely. It is expected that the workwill be performed in a properly equipped laboratory and thatproper waste disposal procedures will be followed.Appropriatequality control practices must be followed such as thosedescribed in Guide E 882.6. Apparatus6.1 Spectrophotometer, capable of
11、 measuring absorbance ata wavelength of 390 nm.6.2 Cells, to fit spectrophotometer, having an optical path of1 cm.NOTE 1Cells having other dimensions can be used, provided suitableadjustments can be made in the amount of sample and reagents used.7. Reagents7.1 Purity and Concentration of ReagentsThe
12、 purity andconcentration of common chemical reagents and water shallconform to Practices E50. The reagents should be free of orcontain only minimal amounts ( 0.1 g/g) of titanium.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals, Ores, and Related Ma
13、terials and is the directresponsibility of Subcommittee E01.08 on Ni and Co and High Temperature Alloys.Current edition approved Dec. 15, 2008. Published January 2009. Originallyapproved in 1997. Last previous edition approved in 2002 as E 1938 02.2For referenced ASTM standards, visit the ASTM websi
14、te, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:
15、/www.ansi.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 Potassium Hydrogen Sulfate (KHSO4).7.3 Ascorbic Acid SolutionDissolve 20 g of ascorbic acid(C6H8O6) in water, dilute to 200 mL, and mix.7.4 Oxalic Acid SolutionDissolv
16、e 10 g of oxalic aciddihydrate (COOH)22H2O in water, dilute to 200 mL, andmix.7.5 Diantipyrylmethane SolutionDissolve 4 g of dian-tipyrylmethane monohydrate (C23H24N4O2H2O) in water con-taining 25 mL HCl (1 + 1). Dilute to 200 mL and mix.7.6 Sodium Chloride SolutionDissolve 117 g of sodiumchloride (
17、NaCl) in water, dilute to 500 mL, and mix.7.7 Titanium Stock Calibration Solution (200 g/mL Ti)Dissolve 0.739 g of potassium titanyl oxalate dihydrateK2TiO(C2O4)22H2O in water. Add 50 mL of H2SO4(1+1)and evaporate to dense fumes. Cool, dilute, and transfer theroom temperature solution to a 500-mL vo
18、lumetric flask.Dilute to the mark and mix.7.7.1 Alternative Preparation:Transfer 0.1000 g of titaniummetal (purity: 99.9 % minimum) weighed to within 6 0.2 mgto a 500-mL glass volumetric flask. Add 50 mL ofH2SO4(1 + 3) and dissolve over low heat. Oxidize the titaniumby adding HNO3dropwise until the
19、blue color is just dis-charged (avoid excess HNO3which will cause the titanium toprecipitate). Cool to room temperature and dilute to volumewith H2SO4(1 + 9).7.8 Titanium Calibration Solution (25 g/mL Ti)Transfer25.0 mL of the titanium stock calibration solution to a 200-mLvolumetric flask. Add 20 m
20、L of H2SO4(1 + 1). Cool thesolution to room temperature, dilute to the mark, and mix.8. Sampling and Sample Preparation8.1 Sampling shall be done by normal procedures agreedupon between the parties, or in the event of a dispute,according to the relevant standard, if one is available.8.2 The laborato
21、ry sample is normally in the form ofmillings or drillings and no further preparation of the sample isnecessary.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, orot
22、her appropriate solvent, and drying in air.8.4 If the sample contains particles or pieces of widelyvarying sizes, the test sample should be obtained by riffling.9. Procedure9.1 Preparation of Test Solution:9.1.1 Test PortionWeigh the test portion of the sample inaccordance with Table 1.9.1.2 Dissolu
23、tion of Test PortionTransfer the test portionto a 125-mLErlenmeyer flask and add 10 mLof HC1 and 3 mLof HNO3. Apply sufficient heat to initiate and maintain thereaction until dissolution is complete. If the alloy resistsdissolution, some adjustment in the acid mixture may berequired.Add HC1 in 1-mL
24、increments and continue heating todissolve the test portion.9.1.3 Preparation of Final Test Solution:9.1.3.1 Add 7 mL of H2SO4(1 + 1) and evaporate thesolution until dense white fumes appear. Cool the contents andproceed as directed in 9.1.3.2 or 9.1.3.3, depending on whethertantalum is present in t
25、he sample or not.9.1.3.2 In the absence of tantalum, add 20 mL of oxalic acidsolution and heat to dissolve the salts. Cool the solution and, intungsten free alloys, proceed as directed in 9.1.4. If the alloycontains tungsten, add sufficient ammonium hydroxide to makethe solution alkaline. Boil the s
26、olution until the tungstic acid isdissolved. Cool the solution and re-acidify by adding 20 mL ofHC1. 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 solutionthrough a tightly packed filte
27、r pulp pad. Wash the precipitatewith warm water. Retain the filtrate. Transfer the pad andprecipitate to a platinum crucible, ignite at 800 C, and cool.Add 1 g of potassium pyrosulfate, cover the crucible with aplatinum lid and fuse carefully over a flame. Cool and transferthe crucible to a 150-mL b
28、eaker containing 20 mL of the oxalicacid solution. Heat carefully until the melt is dissolved. Washand 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 % TitaniumTransfer thetest s
29、olution (see 9.1.3.2 or 9.1.3.3) to a 100-mL volumetricflask, dilute to the mark, and mix.9.1.4.2 Dilution for 1 % to 5 % TitaniumTransfer the testsolution (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 aliq
30、uots of the testsolution to each of two 50-mL volumetric flasks.9.2.2 Add 5.0 mL of HC1 (1 + 1), 5.0 mL of ascorbic acidsolution and 20.0 mL of NaCl solution to both volumetricflasks. Mix the solutions and allow to stand for a few minutes.9.2.3 Add 10.0 mL of diantipyrylmethane solution to one ofthe
31、 volumetric flasks.9.2.4 Dilute both flasks to the mark, mix, and allow to standfor 40 min.9.3 Spectrophotometric Measurement:9.3.1 Using a 1-cm cell, measure the absorbance of bothsolutions against water as the reference at a wavelength of390 nm with the spectrophotometer.9.3.2 Subtract the backgro
32、und absorbance of the test solu-tion from the absorbance of the test solution containing thediantipyrylmethane complex.9.4 Blank TestPerform a blank test in parallel with thedetermination following the same procedure and using thesame quantities of reagents.9.5 Calibration:9.5.1 Using a microburette
33、, transfer (0, 1.0, 2.0, 3.0, 4.0 and5.0) mL of the titanium calibration solution to a series of50-mL volumetric flasks.TABLE 1 Weight of Sample to be TakenExpected Ti Content,%Weight of Test Portion,g0.3 to 3.0 0.19 to 0.213.0 to 5.0 0.09 to 0.11E19380829.5.2 Add HC1 (1 + 1), ascorbic acid and NaCl
34、 solution toeach of the volumetric flasks. Mix the solutions and allow tostand for a few minutes.9.5.3 Add 10.0 mL of diantipyrylemethane solution to eachof the solutions, dilute to the marks, and mix. Allow to standfor 40 min. This series corresponds to (0, 0.5, 1.0, 1.5, 2, and2.5) g titanium per
35、millilitre.9.5.4 Measure the absorbance of the calibration solutions asdescribed in 9.3. Subtract the measured absorbance of the0 g/mL calibration solution from the absorbance values of theremaining calibration solutions.9.5.5 Plot the corrected absorbance values against the re-spective concentratio
36、ns of titanium, in micrograms per millili-tre, in the calibration solutions.9.6 Number of DeterminationsPerform the determina-tions at least in duplicate.9.7 Check Test, The performance of the test method may bechecked by analyzing, in parallel with the determinations andfollowing the same procedure
37、, one or more samples of thesame type alloy whose titanium content is known.10. Calculation10.1 Determine the concentration of the titanium in the testsolutions and the blank by means of the calibration graph.10.2 Calculate the titanium content CTi, expressed as apercentage by weight of the test por
38、tion using the formula:CTi5 A2B!C1024!/5D (1)where:A = the titanium concentration in g/mL of the test solu-tion,B = the titanium concentration in g/mL of the blank testsolution,C = the final dilution volume in mL of the test solution, andD = the sample weight in g.11. Precision and Bias411.1 Precisi
39、onEleven laboratories in four countries par-ticipated in testing this method under the auspices of ISO/TC155/SC4 in the late 1980s and published asISO 11433:1993(E). Four samples of nominal compositiongiven in Table 2 were tested to obtain the statistical informa-tion, as evaluated by ISO 5725:1986
40、and equivalent to PracticeE 1601, summarized in Table 3. Precision may be judged byexamination of these data.11.2 BiasNo information on the accuracy of this testmethod is known because accepted reference standards werenot used in the interlaboratory study. The user of this testmethod is encouraged t
41、o use accepted reference materials, ifavailable, to determine the accuracy of this test method as itapplies in a specific laboratory.12. Keywords12.1 molecular absorption spectrometry; nickel alloy; spec-trophotometric; titanium content4Supporting data have been filed at ASTM International Headquart
42、ers and maybe obtained by requesting Research Report RR: E01-1025.TABLE 2 Nominal Composition of Test Samples (in %)TestMaterialAl Co Cr Fe Hf Mo Nb Ta Ti W NiRE-2 0.5 0.5 20 18 3 5 1.0 BalanceRE-1 5.5 10 9 1.6 2.6 1.5 10 BalanceRE-3 1.9 19 22 1 1.4 3.7 2 BalanceRE-4 3.0 10 14 4 5.0 4 BalanceTABLE 3
43、 Results of Statistical AnalysisTitaniumTestMaterialAMean%Repeatability Index,r (Practice E 1601)Reproducibility Index,R (Practice E 1601)RE-2 0.37 0.019 0.038RE-1 1.49 0.041 0.084RE-3 3.69 0.050 0.088RE-4 5.09 0.063 0.139AMaterial compositions are summarized in Table 2.E1938083ASTM International ta
44、kes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own r
45、esponsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addre
46、ssed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at t
47、he address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E1938084
