Application of the MS7 solid source mass spectrometer to the analysis of iron and low-alloy steel.
Standard samples of high-purity iron and low-alloy steel have been examined systematically on the AEI MS7 mass spectrometer with a view to determining the general levels of accuracy and reproducibility obtainable for impurities in the range 0.001 % to 0.1 %. Twenty-four elements have been determined in different samples by direct examination on the spectrometer and, with a few exceptions, the mean results were found to be in reasonable agreement with the nominal figures. Many elements gave coefficients of variation between 15% and 35% but certain elements such as sulphur, phosphorus, arsenic and lead showed larger deviations. Use of argon ion bombardment to clean the electrodes to reduce the inherent carbon blank and also to determine gas levels has been investigated. Results of the correct magnitude were obtained for nitrogen and carbon although with poor reproducibility. Blank values were not reduced sufficiently to permit any useful values for oxygen to be obtained.
Keene
B J
BJ
National Physical Laboratory, Teddington, Middlesex, U.K.