Characterization of plasma processed ultra-fine Ni–Al powder

Abstract

Thermal plasma processing utilizes the exotic properties of the plasma medium to effect physical, chemical or metallurgical changes/reactions in materials. Commercially available nickel and aluminium powders were mixed in the appropriate amount, ball milled and fed into a dc plasma jet produced by an atmospheric plasma torch. The particles are molten and leave the flame and falls through the atmospheric air inside a plasma reaction chamber. The particles are quenched, solidified and collected in a collection chamber. During in-flight if the particles are overheated, depending on the size, may be partially or fully vaporize. The smaller particles fly in all directions and get deposited on the walls of the reaction chamber. Vapors also condense on the cooled walls. The particles are collected. During in-flight the exothermic reaction to form nickel aluminide may also take place. The particles on the walls of the reaction chamber were collected and characterized using XRD, SEM with EDX and TG\DTA analysis. The results are reported and discussed.