AN ARC MELTING SYSTEM WITH A NON-CONTACT IGNITION

Abstract

Arc melting is a widely used method in materials physics, in general in materials science, as well as in metallurgy, to synthesize new materials starting from high purity constituents. As the high temperature of the technological process is easily attainable, typically arc melting is used to synthesize new materials from metals, and even oxides, with high melting points. In the melting methods usually used the arc is ignited by briefly touching the electrode to the crucible and quickly withdrawing it to a short distance. The contact ignition, however, can contaminate the tip of the tungsten electrode and consequently can reduce the purity of the obtained ingot as compared to the initial components. In order to avoid the contact procedure and thus the purity reduction, an arc non-contact ignition system for melting is proposed in this paper. The arc melting system, the furnace design, the ready for use arc furnace, and the melting procedure, are presented and discussed. Additionally, an arc furnace with a suction attachment to prepare ingots as rods is presented. The clean crystal structures, known from literature, were determined for a number of the compounds synthesized by the non-contact arc method. This quality of crystal structures results mainly from the maintained materials purity during synthesis.