Microplasma Synthesis of Metal Feedstock for Additive Manufacturing

Abstract

By expanding the boundaries of microplasma synthesis of metal feedstock beyond noble metals, this work shows that microplasmas are an excellent tool for the synthesis of a variety of transition metals and alloys. With this expansion into various alloys, microplasma synthesis can become a useful fabrication technique for producing metal feedstock for additive manufacturing due to the traditional methods being energy inefficient processes. In this work, we present results on microparticle formation of select transition metals, bimetallic alloys, such as Invar, and both austenitic and ferritic stainless steel produced through an atmospheric microplasma synthesis with a liquid electrode. We explore the production rates under different plasma parameters and at different electrolytic concentrations to help ensure efficient production of metal feedstock microparticles. During processing, the microplasma was monitored with a Langmuir probe; this assisted in determining that an aqueous solution of cobalt ions provided the best results for stainless-steel particle formation due to their higher kinetic energy in the plasma. With the ability to not only produce elemental transition metal microparticles but also complex metal alloys, such as stainless steel, microplasma synthesis, due to its energy efficiency, is ideal for creating metal feedstock for additive manufacturing.