Investigations on the gas-stabilized micro-spark method in different gas atmospheres used for the emission analysis of steel samples

Ferrous analysis

“…Different gas atomospheres were extensively investigated for use in stabilizing microspark discharge excitation of steels for the determination of a number of elements and argon in combination with graphite or carbon counter electrodes was found to be preferred as a result of this study (513). An in-depth study has also been performed to determine the rate of introduction of various elements from lowand mediumalloy steels into the discharge zone of a Grimm glow discharge lamp so that the optimum calibration graphs for a number of important elements in steel could be produced (349).…”

“…Parts per million of copper in iron ores and limestone samples have been determined after decomposition of the sample and ion exchange separation of the copper by atomic absorption spectrometry (346), in alloy steels by neutron activation analysis (44), and low-alloy steels by potentiometric stripping analysis (541). Copper has also been measured in steels and related products by emission spectroscopic procedures designed for multielement analysis as follows: in stainless steels by both porous and vacuum cup spectrographic excitation (431), in a gas-stabilized microspark discharge excitation method (513), by sequential atomic fluorescence spectrometry with a Grimm-glow type discharge lamp (54), by flame atomic fluorescence spectrometry with a direct current plasma (DCP) source (174), with a laser microanalyzer in a study of steel microhomogeniety in weld zones (163), in a direct determination in steels and ores by laser ablation sampling-DCP excitation (323), and with a computer-controlled monochromator in an ICP atomic emission spectrometer (590). Copper in pure iron has been determined at the trace level by precipitation of the copper with rubeanic acid and XRF measurement of the Cu Ka line in the separated precipitate (224) and in various iron-bearing materials by a pressed-powder XRF measurement (28).…”

“…As expected, because manganese plays such an important role in steelmaking, any description of an improved spectrographic method of analysis of steel is to be used as a quality control or production control tool must include manganese as one of the elements evaluated. Included in the papers that fit this criterion are two evaluations of laser-induced breakdown spectroscopy as applied to steel analysis (36, 82), the determination of the microheterogeneity of steel and weld zones with a laser microanalyzer equipped with a spectrograph (163), the use of a direct current plasma (DCP) as an excitation source for a flame fluorescence spectrometer (174), the use of a laser ablation DCP emission spectrometer for the analysis of steels and some ores (323), a study of two excitation techniques, namely, porous cup and vacuum cup excitation, for the spectrographic analysis of stainless steel (431), an investigation of gas-stabilized microspark excitation procedures in which different gases were evaluated for the emission spectrographic analysis of steels (513), the development of a sample preparation procedure that allowed the spectral analysis, with a unipolar spark source, of various steel foils, wires, and other small parts after dissolution in a mixed acid medium (415), and a patent for the preparation of steel samples for emission spectral analysis that includes shearing a fresh surface with subsequent shot-blasting to stabilize the surface prior to analysis (357).…”

“…In another publication, gas-stabilized microspark excitation of steel samples was studied in detail and the argon-stabilized system yielded higher precision and accuracy than the other gases tried. Relative error for the determination of molybdenum was <5% (513). Highspeed tool steels have been quantitatively analyzed for molybdenum content by ICP glow spectroscopy as described in another recent paper (19).…”

“…Another study focused on the use of either the porous cup or the vacuum cup for stainless steel excitation and analysis by emission spectroscopy and concluded that the vacuum cup was more accurate in performance (431). Different gaseous atmospheres were investigated for stabilizing microspark discharges used for the determination of nickel and other elements in steel; argon gas with carbon or graphite counter electrodes were favored (513). Atomic fluorescence spectrometry with a Grimm-type glow discharge lamp has been described for the determination of nickel and several other elements in steels and was found to compare to dispersive spectrometric techniques (54).…”