Josh Aller PhD Comp Exam presentation
- Wednesday, October 14, 2015 at 10:00am
- Roberts Hall, Room 219 - view map
High Temperature Chlorosilane Corrosion of Iron, Nickel, Chromium, and their Alloys
Chlorosilane gas streams are used at high temperatures (>500°C) throughout the semiconductor, polycrystalline silicon, and fumed silica industries, primarily as a way to refine, deposit, and produce silicon and silicon containing materials. The presence of both chlorine and silicon in chlorosilane species creates a unique corrosion environment due to the ability of many metals to form both metal-chloride and metal-silicides. The predominance of metal-chloride or metal-silicide formation is important to understand in both applied and fundamental settings. The immediate, direct application of this research is within the polycrystalline silicon industry where metallic structural components and pressure vessels must withstand the corrosion from chlorosilane gas streams. Fundamentally, there is interest in understanding the competitive formation of chloride and silicide species in these environments. The objective of this proposal is to investigate the conditions that promote metal-chloride or metal-silicide formation of structural metals in chlorosilane service using both experimental results and thermodynamic predictions. A better understanding of corrosion in chlorosilane environments will directly reduce the cost of producing polycrystalline silicon, which will help make silicon based photovoltaics more cost competitive with traditional forms of energy.