1、Designation: E 1938 02Standard Test Method forDetermination of Titanium in Nickel Alloys by theDiantipyrylmethane Molecular Absorption SpectrometricMethod1This standard is issued under the fixed designation E 1938; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of titanium innickel alloys in
3、the 0.3 through 5.0 % range. 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 % Ti for every 1 % Mo.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wit
4、h 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 prior to use. For specific hazardsassociated with the use of this test method see Practices E50.2. Referenced Documents2.1
5、ASTM Standards:2E50 Practices for Apparatus, Reagents, and Safety Precau-tions for Chemical Analysis of MetalsE 882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE 1452 Practice for Preparation of Calibration Solutions forSpectrophotometric and for Spectroscopic Atom
6、ic Analy-sisE 1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method2.2 ISO Standards:ISO 5725:1986 - Precision of Test Methods Determina-tion of Repeatability and Reproducibility for a StandardTest Method by Inter-Laboratory Tests3ISO 11433:1993(E)
7、- Nickel Alloys - Determination ofTitanium Content - Diantipyrylmethane Molecular Ab-sorption Spectrometric Method33. Summary of Test Method3.1 This sample is dissolved in a mixture of hydrochloricand nitric acid. The solution is evaporated to sulfuric acidfumes to remove the hydrochloric and nitric
8、 acids. Color isdeveloped with diantipyrylmethane, and the absorbance ismeasured at 390 nm.4. Significance and Use4.1 This practice is used for the analysis of nickel and nickelbase alloy samples by molecular absorption spectrometry tocheck compliance with compositional specifications. It isassumed
9、that all who use the procedure will be trained analystscapable of performing common laboratory procedures skill-fully and safely. It is expected that the work will be performedin a properly equipped laboratory and that proper wastedisposal procedures will be followed. Appropriate qualitycontrol prac
10、tices must be followed such as those described inGuide E 882.5. Apparatus5.1 Spectrophotometer, capable of measuring absorbance ata wavelength of 390 nm.5.2 Cells, to fit spectrophotometer, having an optical path of1 cm.NOTE 1Cells having other dimensions can be used, provided suitableadjustments ca
11、n be made in the amount of sample and reagents used.6. Reagents6.1 Purity and Concentration of ReagentsThe purity andconcentration of common chemical reagents shall conform toPractices E50. The reagents should be free of or contain onlyminimal amounts ( 0.1 g/g) of titanium. Calibration solu-tions s
12、hall be prepared in accordance with Practice E 1452.6.2 Potassium Hydrogen Sulfate (KHSO4).6.3 Ascorbic Acid SolutionDissolve 20 g ascorbic acid(C6H8O6) in water, dilute to 200 mL and mix.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry of Metals, Ores and Rel
13、ated Materials, and is the directresponsibility of Subcommittee E01.08 on Nickel, Cobalt and High TemperatureAlloys.Current edition approved Oct 10, 2002. Published June 2003. Originallyapproved in 1997. Last previous edition approved in 1997 as E 193897.2For referenced ASTM standards, visit the AST
14、M website, 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, 11 West 42nd Street,New York, NY 10036.1Copyright A
15、STM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.4 Oxalic Acid SolutionDissolve 10 g of oxalic aciddihydrate (COOH)22H2O in water and dilute to 200 mL andmix.6.5 Diantipyrylmethane SolutionDissolve4gofdian-tipyrylmethane monohydrate (C23H24N4O2
16、H2O) in water con-taining 25 mL hydrochloric acid (1+1). Dilute with water to200 mL to mix.6.6 Sodium Chloride SolutionDissolve 117 g of sodiumchloride (NaCl) in water and dilute to 500 mL and mix.6.7 Titanium Stock Calibration SolutionDissolve 0.739 gof potassium titanyl oxalate dihydrate K2TiO(C2O
17、4)22H2O inwater.Add 50 mL of sulfuric acid (1+1) and evaporate to densefumes. Cool and dilute with water. Cool and transfer the roomtemperature solution to a 500 mL volumetric flask. Dilute tothe mark with water and mix.Alternative Preparation:Transfer 0.1000 g of titanium metal(purity: 99.9% min.)
18、weighed to within 6 0.2 mg to a 500-mLglass volumetric flask. Add 50 mL of H2SO4 (1+3) anddissolve over low heat. Oxidize the titanium by adding HNO3dropwise until the blue color is just discharged (avoid excessHNO3 which will cause the titanium to precipitate). Cool toroom temperature and dilute to
19、 volume with H2SO4 (1+9).6.8 Titanium Calibration Solution (25g/mL)Transfer25.0 mL of the titanium stock calibration solution (see 6.7)toa 200 mL volumetric flask. Add 20 mL of sulfuric acid (1+1).Cool the solution to room temperature, dilute to the mark withwater and mix.7. Sampling and Sample Prep
20、aration7.1 The sampling shall be carried out by normal proceduresagreed upon between the parties, or in the event of a dispute,according to the relevant standard, if one is available.7.2 The laboratory sample is normally in the form ofmillings or drillings and no further preparation of the sample is
21、necessary.7.3 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 anddrying in air.7.4 If the sample contains particles or pieces of widelyvarying sizes, the test sample sh
22、ould be obtained by riffling.8. Interlaboratory Studies (ILS)8.1 This test method was evaluated by a subcommitteewithin ISO Technical Committee 155 (ISO/TC 155/SC 4) onanalysis of nickel alloys, in accordance with ISO Standard5725. It was published as ISO Standard 11433. ILS test datawere not availa
23、ble for recalculation.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 Dissolution of Test PortionTransfer the test portionto a 125-mLErlenmeyer flask and add 10 mLof HC1 and 3 mLof HNO3. Apply sufficient heat to init
24、iate and maintain thereaction until dissolution is complete. If the alloy resistsdissolution, some adjustment in the acid mixture may berequired.Add HC1 in 1-mL increments and continue heating todissolve the test portion.9.1.3 Preparation of Final Test Solution9.1.3.1 Add 7 mL H2SO4(1+1) and evapora
25、te the solutionuntil dense white fumes appear. Cool the contents and proceedas directed in 9.1.3.2 or 9.1.3.3, depending on whether tanta-lum is present in the sample or not.9.1.3.2 In the absence of tantalum, add 20 mL oxalic acidsolution and heat to dissolve the salts. Cool the solution and, intun
26、gsten free alloys, proceed as directed in 9.1.4. If the alloycontains tungsten, add sufficient ammonium hydroxide to makethe solution alkaline. Boil the solution until the tungstic acid isdissolved. Cool the solution and reacidify by adding 20 mL ofHC1. Cool the solution and proceed as directed in 9
27、.1.4.9.1.3.3 In the presence of tantalum add 30 mL of water, heatto dissolve the salts and cool again. Filter the solution througha tightly packed filter pulp pad. Wash the precipitate with warmwater. Retain the filtrate. Transfer the pad and precipitate to aplatinum crucible, ignite at 800C, and co
28、ol. Add1gofpotassium pyrosulfate, cover the crucible with a platinum lidand fuse carefully over a flame. Cool and transfer the crucibleto a 150-mL beaker containing 20 mL of the oxalic acidsolution. Heat carefully until the melt is dissolved. Wash andremove the platinum crucible. Combine the oxalate
29、 solutionwith 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 solution (see 9.1.3.1 or 9.1.3.2) to a 100-mL volumetricflask, dilute to the mark with water and mix.9.1.4.2 Dilution for 1 to 5 % TitaniumTransfer the tes
30、tsolution (see 9.1.3.1 or 9.1.3.2 ) to a 250-mL volumetric flask,dilute to the mark with water and mix.9.2 Color Development:9.2.1 With a pipet, transfer 5.0-mL aliquots of the testsolution (see 9.1.4.1 or 9.1.4.2) to each of two 50-mL volu-metric flasks.9.2.2 Add 5.0 mL of HC1 (1+1), 5.0 mL of asco
31、rbic acidsolution (see 6.3) and 20.0 mL sodium chloride solution (see6.6) to both volumetric flasks. Mix the solutions and allow tostand for a few minutes.9.2.3 Add 10.0 mL diantipyrylmethane solution (see 6.5)toone of the volumetric flasks.9.2.4 Dilute both flasks (see 6.2.2 and 6.2.3) to the markw
32、ith water, mix and allow to stand for 40 min.9.3 Spectrophotometric Measurement:9.3.1 Using a 1-cm cell, measure the absorbance of bothsolutions (see 9.2.4) against water as the reference at awavelength of 390 nm with the spectrophotometer (see 5.1).9.3.2 Subtract the background absorbance of the te
33、st solu-tion from the absorbance of the test solution containing thediantipyrylmethane complex.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 0.11E19380229.4 Blank TestCarry out a blank test in parallel with thedetermination
34、 following the same procedure and using thesame quantities of reagents.9.5 Calibration:9.5.1 Using a microburette, transfer 0, 1.0, 3.0, 4.0 and5.0-mL of the titanium calibration solution to a series of 50 mLvolumetric flasks.9.5.2 Add HC1 (1+1), ascorbic acid and sodium chloridesolution to each of
35、the volumetric flasks as described in 9.2.2.9.5.3 Add 10.0 mL of diantipyrylemethane solution (see6.5) to the solutions, dilute to the marks and mix. Allow tostand for 40 min. This series corresponds to 0, 0.5, 1.0, 1.5, 2,and 2.5 g titanium per millilitre.9.5.4 Measure the absorbance of the calibra
36、tion solutions asdescribed in 9.3. Subtract the measured absorbance of the 0g/mL calibration solution from the absorbance values of theremaining calibration solutions.9.5.5 Plot the corrected absorbance values against the re-spective concentrations of titanium, in micrograms per millili-tre, in the
37、calibration solutions.9.6 Number of DeterminationsCarry out 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, one or more samples of thesame type alloy whose ti
38、tanium content is known.10. Calculation10.1 Determine the concentration of the titanium in the testsolutions and the blank by means of the calibration graph (see9.5.5) using the absorbance readings obtained in 9.3.2 and 9.4.10.2 Calculate the titanium content CTi, expressed as apercentage by weight
39、of the test portion using the formula:CTi5 A2B!C1024!/5D (1)where:A = the titanium concentration in g/mL of the test solution(see 10.1),B = the titanium concentration in g/mL of the blank testsolution (see 10.1),C = the final dilution volume in mL of the test solution (see9.1.4.1 or 9.1.4.2), andD =
40、 the sample weight in g.11. Precision and Bias411.1 PrecisionEleven laboratories cooperated in the test-ing of this test method and obtained the statistical informationsummarized in Table 2 and Table 3.11.2 BiasNo information on the accuracy of this testmethod is known because accepted reference sta
41、ndards werenot used in the ILS. The user of this test method is encouragedto employ accepted reference materials, if available, to deter-mine the accuracy of this test method as it applies in a specificlaboratory.12. Keywords12.1 colorimetric; molecular absorption; nickel; spectropho-tometric; titan
42、ium content4Supporting data are available from ASTM International Headquarters, RequestRR:E01-1025.TABLE 2 Nominal Composition of Test Samples (in %)TestMaterialAl Co Cr Fe Hf Mo Nb Ta Ti W NiRE-1 5.5 10 9 1.6 2.6 1.5 10 BalanceRE-2 0.5 0.5 20 18 3 5 1.0 BalanceRE-3 1.9 19 22 1 1.4 3.7 2 BalanceRE-4
43、 3.0 10 14 4 5.0 4 BalanceTABLE 3 Results of Statistical AnalysisTitaniumTestMaterialAMean%Repeatability SD(Sr, ISO 5725)BReproducibility SD(SR, ISO 5725)CReproducibility(R, ISO 5725)DRrel %RE-2 0.37 0.007 0.012 0.038 10RE-1 1.49 0.015 0.026 0.084 5.6RE-3 3.69 0.018 0.026 0.088 1.3RE-4 5.09 0.022 0.
44、044 0.139 1.2AMaterial compositions are summarized in Table 2.BEquivalent to minimum standard deviation, SM, (see Practice E 1601).CEquivalent to reproducibility standard deviation, SR, (See Practice E 1601).DEquivalent to reproducibility index, R, (See Practice E 1601).E1938023ASTM International ta
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47、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
48、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).E1938024
