ASTM_E_1938_-_13.pdf

Designation:E193813Standard Test Method forDetermination of Titanium in Nickel Alloys byDiantipyrylmethane Spectrophotometry1This standard is issued under the fixed designation E1938;the number immediately following the designation indicates the year oforiginal adoption or,in the 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%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 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 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 MaterialsE135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method2.2 ISO Standards:3ISO 5725:1986 Precision of Test MethodsDeterminationof 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 testmethod,refer to Terminology E135.4.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 withdiantipyrylmethane,and the absorbance is measured at390 nm.5.Significance and 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 laboratoryprocedures 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 E882.6.Apparatus6.1 Spectrophotometer,capable of measuring absorbance ata wavelength of 390 nm.6.2 Cells,to fit spectrophotometer,having an optical path of1 cm.NOTE1Cells 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 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 Materials and is the directresponsibility of Subcommittee E01.08 on Ni and Co and High TemperatureAlloys.Current edition approved Oct.1,2013.Published November 2013.Originallyapproved in 1997.Last previous edition approved in 2008 as E1938 08.DOI:10.1520/E1938-13.2For referenced ASTM standards,visit the ASTM 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(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 States1 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 SolutionDissolve 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(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 volumetric