High-Temperature Amorphous Coating for CMCs for Protection against Oxygen Embrittlement

This Phase II.5 effort will further develop and mature the sealing technology relevant to JSF exhaust ceramic matrix composite (CMC) nozzle components. Significant concerns related to the poor durability of the CMC in the engine environment remain and this sealing technology, under Phase II, has demonstrated excellent capability to protect SiC-based CMCs in harsh environments. Under the Phase II.5 effort, extensive testing in close collaboration with the prime contractor and development of suitable sealing processes to accommodate the geometry and size of the full-scale nozzle component will be pursued. The primary outcome of Phase II.5 will be the implementation of Phase III program for the eventual transition of the sealing process for production. The sealing product will also enhance the reliability of the component in service which is a critical issue for the deployment of CMCs. In addition, the extended lifetime/durability provided by Cerablak™ sealing will yield notably lower lifecycle costs. In a broader perspective, this sealing technology represents a major breakthrough toward the use of these CMCs for aeroengine applications, and the Phase II.5 will progress this technology toward qualification for engine hardware.