Characterization of the Atomic Emission in Inconel 718 Alloy Metal Vapor Arcs

摘要

Visible and uv emission spectroscopy was used to identify and study various atomic species in the plasma of a vacuum arc furnace during a remelt of Inconel 718. The studies were carried out at a base pressure of 10 mtorr, and with the furnace backfilled with CO to a total pressure of 100 mtorr. Various emitting species were identified, and the internal energy distributions of a number of these species were mapped out using Boltzmann plots. Internal temperatures of 6000 to 7000 deg K were measured for the neutral atomic species in the low pressure arc, while a value of 11,600 deg K was obtained for the ion temperature. In addition, the density of the highly volatile element Mn in the interelectrode region was found to be greatly enhanced compared to its relative abundance in the bulk alloy, indicating the importance of vaporization in determining the atomic composition of the arc plasma. Increasing the furnace pressure resulted in an increase in the temperature of the neutral species of 1500 to 4000 deg K, and an apparent suppression of the Mn vaporization rate. (ERA citation 11:040982)