Gas-phase combustion synthesis (GCS) has become the industry standard for the production of high-volume powders like silicon dioxide, titanium dioxide and carbon black, but until recently could not produce nonagglomerated, non-oxide materials. Despite past limitations, LACER has demonstrated and commercialized a GCS process to produce ultrafine, nonagglomerated, non-oxide ceramic, metal and composite powders. The process couples a unique combustion system — consisting of a reactive metal (e.g., sodium) and one or more halide compounds — with a novel encapsulation technique. This approach represents an opportunity to produce large quantities of many technologically significant nanomaterials at a low cost.
The process was commercialized by a start-up company, AP Materials, which was subsequently acquired by Cabot Corp.
Called the sodium/halide flame and encapsulation (SFE) process, this process overcomes a number of barriers that have plagued other methods of synthesizing ultrafine metal and non-oxide ceramic powders. Specifically, to inhibit agglomeration and shield particles from contamination when handled in air, the particles are encapsulated in situ immediately following formation. Encapsulation is extremely important for air-sensitive materials in order to avoid subsequent contamination during air exposure. Encapsulation can also narrow the size distribution of core particles.
The onset of encapsulation is determined by reaction conditions, which can be manipulated to ensure that the particles are the correct size. The encapsulation material may be removed after subsequent handling (e.g., during consolidation), eliminating exposure to air.