Browsing by Author "Mason, Ryan"

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Carbide Derived Carbon Production at MSU
(Montana State University, 2017-04) Mason, Ryan
Carbide Derived Carbons (CDCs), are unique materials in that their porosity can be carefully tuned based upon the precursor carbide from which they are derived. CDCs have many potential applications in the fields of material science and engineering including, but not limited to: separations; fuel cells; supercapacitors; gas storage; and tribology. CDCs are commonly produced using halogenation (chlorine being the most commonly utilized halogen) at high temperature, in which the halogen reacts with non-carbon elements in the carbides to form volatile halide species. The reactive vaporization of non-carbon elements accounts for the regular porosity, which can be controlled by altering parameters such as initial carbide, reaction temperature, and halogen species. This poster reports efforts to synthesize and characterize CDCs using both conventional and novel synthesis approaches, with the aim of understanding relationships among CDC processing, structure, properties and performance, along with assessing commercial-scale production.
High-Temperature (550-700 degrees C) Chlorosilane Interactions with Iron
(2016-08) Aller, Josh; Mason, Ryan; Walls, Kelly; Tatar, Greg; Jacobson, Nathan; Gannon, Paul
Chlorosilane species are commonly used at high temperatures in the manufacture and refinement of ultra-high purity silicon and silicon materials. The chlorosilane species are often highly corrosive in these processes, necessitating the use of expensive, corrosion resistant alloys for the construction of reactors, pipes, and vessels required to handle and produce them. In this study, iron, the primary alloying component of low cost metals, was exposed to a silicon tetrachloride-hydrogen vapor stream at industrially-relevant times (0-100 hours), temperatures (550-700 degrees C), and vapor stream compositions. Post exposure analyses including FE-SEM, EDS, XRD, and gravimetric analysis revealed formation and growth of stratified iron silicide surface layers, which vary as a function of time and temperature. The most common stratification after exposure was a thin FeSi layer on the surface followed by a thick stoichiometric Fe3Si layer, a silicon activity gradient in an iron lattice, and finally, unreacted iron. Speculated mechanisms to explain these observations were supported by thermodynamic equilibrium simulations of experimental conditions. This study furthers the understanding of metals in chlorosilane environments, which is critically important for manufacturing the high purity silicon required for silicon-based electronic and photovoltaic devices.