Performance of the analytical techniques employed in characterization and certification of stainless steel materials by Ingemar Gustavsson Analytical Chemistry Group Corrosion and Metals Research Institute Drottning Kristinas väg 48 SE Stockholm, Sweden

Definitions of RMs and CRMs according to ISO-Guides ____________________________ Reference Material (RM) A material, sufficiently homogeneous and stable with respect to one or more properties, which have been established to be fit for its intended use in a measurement process Certified Reference Material (CRM) An RM characterized by a metrologically valid procedure, accompanied by a certificate that states the value of the specified property, its associated uncertainty, and a statement of metrological traceability

Characteristic steel elements Concentrations given in % (m/m) C, Si, Mn, P, S, Cr, Mo, Ni, N, (Fe) C0,01 - 2Si0, Mn0,3 - 12P0, ,02 S0, ,2Cr0, Mo0, Ni0, N0, ,3Fe Low alloy steel C, Si, Mn, P, S, N High alloy steel C, Si, Mn, P, S, Cr, Mo, Ni, N (Stainless steel) Tool steelC, Si, Mn, P, S, Cr, Mo, Ni, N, W, V, Co Special steelC, Si, Mn, P, S, Cr, Mo, Ni, N plus e.g. Al, Si, Nb, Ti, Cu, Ce

Chemical analysis of stainless steel C and S Combustion - infrared detection (C - 0,003-4,5 %; S - 0, ,2 %) –Oxidation by oxygen gas at 2100 o C; formation of CO 2 and SO 2 –Calibration against BaCO 3 ; Na 2 CO 3 or sucrose –Calibration against K 2 SO 4 –(Calibration against CRMs)

Chemical analysis of stainless steel Si - Spectrophotometry (0,01-0,2%) –Dissolution by H 2 SO 4 /HNO 3 –Filtartion –Ignition of acid-insoluble Si with Na 2 O 2 –Add MnO solution - pink solution –Add MoO solution –Add ascorbic acid solution - formation of molybdosilicate complex (blue) –Measurement at 810 nm –Calibration against SiO 2 -solution Si - Gravimetry (0,1 - 5 %) –Oxidation by HClO 4 -fuming-formation of SiO 2 –Filtration –Addition of HF - formation of SiF 4 –Ignition –Weighing

Chemical analysis of stainless steel Mn - AAS - flame (0, %) –Dissolution by HCl/HNO 3 (HF) –Add HClO 4 - fuming –Filtration –Measurement at 279,5 nm –Calibration against matrix-matched Mn - solution

Chemical analysis of stainless steel P - Spectrophotometry (0, ,0 %) –Dissolution by HCl/HNO 3 (HF) –Add HClO 4 - fuming –Cr content > 0,1 % is removed by addition of HCl - formation of volatile CrO 2 Cl 2 –Add NaNO 2 - reduction of dichromate –Add H 3 BO 4 - formation of tertafluoroboric acid –Add metavanadate and heptamolybdate solutions- formation of phosphovanadomolybdate complex –Extraction with 4-methyl-2-pentanone –Measurement of organic solvent at 355 nm –Calibration against KH 2 PO 4 (orthophosphate) - solution

Chemical analysis of stainless steel Cr and V - Potentiometric titration Cr ( %); V (0, %) –Dissolution by HCl/HNO 3 /HF in aTeflon pressure vessel in micro-wave assisted system –Add H 3 PO 4 /H 2 SO 4 - oxidation to Cr(VI) and to V(V), respectively –Titration with Fe(II) giving Cr(III) and V(IV) –Oxidation with MnO 4 - -solution giving V(V) and not Cr(VI) –Excess of MnO 4 - is reduced by NO 2 - –Excess of NO 2 - is eliminated by urea –Standardisation using pure K 2 Cr 2 O 7

Chemical analysis of stainless steel N - Melt extraction - Thermal Conductivity (0, ,6 %) –Melt extraction at 2700 o C in graphite crucible and purging helium –Calibration against KNO 3 –(Calibration against CRMs)

Chemical analysis of stainless steel O - Melt extraction - Infrared detection (0, ,02 %) –Melt extraction at 2200 o C in graphite crucible and purging helium –Calibration against KNO 3 –Calibration against Dy 2 O 3 alt TeO 2 –(Calibration against CRMs)

Chemical analysis of stainless steel Trace elements (< 0,01 %) Li, Be, B...Ti…Nb, Mo…Sn, Sb… Ce, La…W…Pb, Bi, Th, U –Dissolution in HCl/HNO 3 /(HF) in a Teflon pressure vessel using a micro-wave assisted system –Dilution to suitable analytical volume –Addition of internal standard (usually 1- 3) of Y, Rh, In, Re, Ir, Tl –Calibration against matrix-matched elemental solutions

Round-Robin test. Concentrations of 30 elements in a high alloy steel - JK 37. n = number of participating laboratories; concentrations in g/g Major elementnCert.value Mn Micro elements Si P V Co Ce Pr Nd Trace elements B Al Ti Ga45 95 As Nb13 15 Sb Te W84 85 Pb (Cert.values (%) : Cr-26.72;Ni-30.82;Mo-3.55)

Cont`d Round-Robin test. Concentrations of ultra-trace elements in a high alloy steel - JK 37. n = number of participating laboratories; concentration in g/g Ultra-trace elementsnCert.value Be<0.14 Pd<12 Ag<0.44 Ba<14 Ta<0.25 Ir Pt<0.25 Tl<0.24 Bi Trace or ultra-trace elements ? Ca<124 Zn<52 Se<102

ICP-TOFMS - LECO Renaissance

Laser Ablation System CETAC LSX-200 plus

Instrument installation

ICP-TOFMS Flight tube

LECO - Renaissance Typical fly times for ten elements

ICP-TOFMS Analysis of wet-digested low alloy steel samples Concentrations given in µg/g (ppm)

*Figures in italics refer to earlier determinations carried out by five different laboratories ICP-TOFMS Analysis of wet-digested high alloy steel samples Concentrations given in µg/g (ppm)

Laser Ablation Copper scanning- spot size 200 µm

Laser Ablation Analysis of Copper Copper samples: BAM 381 BAM 383 BAM 382 BAM 385 All BAM samples above have been determined in a traditional wet chemical way by ICP-TOFMS LASER measurements: Calibration with BAM 381, 384 and 385 Internal standard Sn 118 or Ag 107 Determination of BAM 383

LA-ICP-TOFMS and ICP-TOMS Comparison of trace element determinations

Laser Ablation Analysis of Steel Steel Samples: JK 1CPure Iron ECRM 090-1Carbon Steel EZRM 179-2Tool Steel HOØ47 (Ovako)Ball Bearing Steel Calibration with: JK 1C, ECRM 090-1, EZRM Internal standards: Ga and Ni Samples analysed: HOØ47 (Ovako)

Laser Ablation Comparison of determinations

Laser Ablation Analysis of Zircaloy Zircaloy samples: 9 authentic samples Calibration with: Jaeri-Z11 and two in-door samples Internal standards:

Laser Ablation - Zircaloy samples Calibration for Cr 50 with internal standard

Laser Ablation - Zircaloy samples Calibration for Cr 50 with no internal standard

Laser Ablation - Zircaloy samples Comparison of trace element determinations

Laser Ablation Depth profiling analysis of Al Parameters:Al-layer content: (100 µm thickness) Spot size50 µmSi 7.4 ± 0.2 % Energy3.8 mJMn<0.01 % Frequency20 HzMg<0.01 % Integ. time102 msPb 0.01 % Data points1760 / isotopeTi<0.01 %

Laser Ablation Depth profiling graph for two Al-layers

Thickness of coating layers according to: - TiN1 µm - Al 2 O 3 4 µm - Ti (C, N)1 µm Three coating layers of a cutting tool

Laser Ablation - Transient signals of the elements Al, Co, Ti and W on a cutting tool

Laser Ablation - Depth profile curve for Hg of an old zinc coated steel sheet Thickness of Hg-layer µm

Laser Ablation - Depth profile curve for Hg of a scrap steel sample Thickness of Hg-layer µm

Conclusions LA-ICP-TOFMS vs ICP-TOFMS: - a fast method compared with wet chemical analysis - a fast method for depth profile analysis - a tool for trace element determinations in steel and metals - a promising tool for determination of inhomogenieties (inclusions) in steel and metals