Blue Origin

Optimizing Pack Cementation for Next-Gen Reusable Heat Shields

Blue Origin utilizes Carbon/Carbon (C/C) composites for flight-critical components because the material tolerates extreme temperatures in inert gas and vacuum, but it remains vulnerable to oxidation during atmospheric ascent, descent, and re-entry. To support lower-cost production of oxidation-resistant coatings, this project focused on improving understanding of the pack cementation process used to form a protective silicon carbide layer on C/C surfaces. This work builds on foundational experimental and analytical research by Prof. Mueller at the University of Washington, who developed earlier versions of these oxidation-resistant coating systems. The coating process embedded parts in a powder mixture of silicon, silicon carbide, alumina, and fumed silica inside a graphite retort, then heated the assembly above 1600°C to drive reactions that converted the surface to silicon carbide. As an initial phase, the project proposed thermogravimetric analysis with mass spectrometry to characterize mass change during heating, identify gaseous species released through the firing cycle, and determine critical temperatures associated with the underlying reactions. The student team worked to provide the thermodynamic and kinetic insight needed to better control and optimize the coating process.