SIMULTANEOUS ANALYSIS OF NICKEL, COBALT AND IRON BASE ALLOYS USING THE FUNDAMENTAL PARAMETER METHOD

The method of analysis of nickel, cobalt, and iron base alloys by using the fundamental parameter method, covering the entire concentration range with a single calibration for each element is evaluated. The results obtained were satisfactory and demonstrated that the method can be applied to the analyses of both, major and trace elements using a multi-channel spectrometer. For example, 0.14wt% of accuracy was obtained for nickel within a concentration range of 0 to 100wt%. We found that tertiary excitation is significant in the analysis of chromium by contributing up to 2.4% of the total intensity; the accuracy was improved from 0.14wt% to 0.10wt% by incorporating tertiary excitation in the computation of theoretical intensities. The least squares fitting method for sensitivity calibration was studied; the method with a quadratic fit polynomial pinned to a fixed point gave the best result, covering a range from trace level to 100% with a single calibration line. The theoretical intensity overlapping correction method is effective when channels for overlapping lines are not available in a multi- channel spectrometer.