Gas phase sodium flame synthesis of non-oxide metallic powders

A. Abid, G. Smith, M. Krause, A. Yin, C. Sungail
GAM,
United States

Keywords: non-oxide, high-purity, refractories, flame synthesis, nanopowders, high surface area

Summary:

Demand for new high surface area non-oxide materials is growing to support the diverse market such as energy storage, catalysts, electronic materials etc. Tight control of powder purity and flow properties are important parameters for high performing components. In particular oxygen impurities can adversely affect part physical properties of high value metals such as titanium and tantalum. Here we describe a novel materials synthesis process for producing non-oxide metals, alloys, ceramics, intermetallics and metal matrix composites. Sodium vapor reacts hypergolically with metal chlorides to form high surface area powder with primary particle size less than 30 nm. These powders are salt encapsulated, of very high purity and sinter active. Tight control of powder size distribution and morphology (from spherical to open aggregate structures) can be achieved by adjusting process temperature profiles and mixing rates. The flame process is continuous and inherently scalable. Salt removal can be achieved by washing or vacuum sublimation. Potential uses for flame synthesized feed powders for AM application are also reviewed.