Characterization of Spark Erosion of Metal Alloys.
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
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A new spectroscopic emission technique, inductively coupled plasma ICP optical emission spectroscopy, in conjunction with spark erosion or conductive solids nebulization CSN, was used in obtaining rapid elemental analysis of metal alloys. Enthalpies of vaporization were shown not be the determining factor in the amount of material eroded in medium-voltage sparks. The melting behavior of the alloys seems to have a more significant effect on the amount of material eroded. Perhaps, instead of direct vaporization, the mechanism of erosion involves the mechanical sputtering of molten metal into the aerosol. However, in a standard spark source, for which both erosion and excitation occur simultaneously, the sample eventually must be vaporized to give an atomic emission signal. While it might be expected that melting would comparative measurements of iron emission signals from iron-nickel and iron-chromium alloys, using a standard spark system, yield results simular to those observed in this work the chromium alloys show much less iron intensity than nickel alloys with the same iron concentration. The important factor may be the amount of material present in the discharge gap, where vaporization and excitation take place. The sputtering of material into the gap, and thus a melting behavior, would then be important even in a standard spark stand. Keywords Physical chemistry, Inorganic chemistry, Metallurgy and metallography metal alloys, Spark erosion, Spark emission analysis, Conductive solids nebulization CSN, Inductively coupled plasma ICP optical emission spectroscopy.
- Properties of Metals and Alloys