Applications - Coatings / Thin films
Chemical Vapor Infiltration/Deposition (CVI/CVD) is easier and safer with Starfire CVI/CVD precursors. The conventional approach to CVI/CVD uses a chemical compound such as methyltrichorosilane (MTS) or trimethylsilane (TMS) mixed with a reactive carrier gas such as hydrogen. It is then introduced into a chamber containing a heated substrate, usually a fiber preform, where it thermally decomposes to form silicon carbide and by-products such as hydrogen chloride gas (HCl). CVI/CVD has been the preferred process for fabricating fiber reinforced composite ceramics and for producing high purity SiC for electronic applications. But the process is very slow due to low ceramic yields and deposition rates, requiring weeks to complete a part. The starting materials are typically corrosive, hazardous liquids or flammable gases. The effluents (HCl) are highly corrosive, resulting in frequent equipment maintenance and significant downtime (loss of production). In addition, the equipment required for CVI/CVD is expensive ($200,000 - $300,000). There are also problems with coating uniformity and density gradients in thick parts. Typically, part thickness is limited to less than ½ inch and uniformity in large size parts is difficult to achieve. Starfire technology offers unique environmental advantages that avoid hazardous liquids and corrosive materials, producing products and by-products that are non-toxic.