Determination of Cu, Zn, As, Cd, In, Sn, Pb, and Bi in nickel-based superalloys after multi-matrix separation

摘要

A procedure has been developed for the determination of critical elements such as Cu, Zn, As, Cd, In, Sn, Pb, and Bi present at trace/ultra-trace levels in different types of Ni-based superalloys. These elements were quantitatively separated from a multicomponent superalloy (nearly 10 major constituents) by a solvent extraction method using 1M KI + 2M H2SO4 medium, then extracted into MIBK (Methyl Isobutyl Ketone), and determined by Inductively Coupled Plasma Quadrupole Mass Spectrometry (ICP-QMS). Significant separation of all the major matrix elements (Al, Ti, V, Cr, Co, Nb, Mo, Hf, Ta, W, Ni, and Re) has been achieved. Recoveries of > 95% were achieved for the elements Cu, Zn, Cd, In, Sn, Pb, and Bi, and 85% for As. Good agreement was observed for these results with the certified values of British Chemical Standard (BCS 346) and with the values obtained from the direct analysis by Glow Discharge Quadrupole Mass Spectrometry (GD-QMS). Reproducibility of the procedure is 20% RSD and the accuracy is within +/- 25% for the elements at trace levels. The procedure provides detection limits of 0.7 mu g kg(-1) (Bi) and 0.07 mg kg(-1) (Zn).