Multifunctional Thermal-Environmental Barrier Coatings for High Temperature Composites

The specific requirement listed in sub-topic C58-25a targets the need for advanced multifunctional thermal- environmental barrier coatings (T/EBC) on ceramic matrix composites in an advanced hydrogen gas turbine environment. ReliaCoat Technologies and the team proposes a multifaceted development and potential technology transition strategies for: (a) Strategic material selection via insights based on experience and analytical solutions to simultaneously meet the functional, thermal, chemical, and structural integrity requirements with input/feedback from our industrial partners (b) model-guided design of appropriate functional multilayer architecture, incorporating location specific as well as thermomechanical and thermochemical compatibility (c) Novel layered manufacturing methods taking advantage of unique attributes of thermal spray processes while mitigating some of the challenges ensuring manufacturing reliability considerations at each step (d) novel approaches to controlled water vapor content furnace cycle (Oak Ridge National Laboratory) simulated burner rig testing in a high heat flux thermal gradient.(e) Iterative optimization of design, materials and manufacturing based on performance assessment. ReliaCoat Technologies proposes: (1) Replacement of silicon bond coat through either direct deposition of EBCs or via the use of novel silicide bond coats of similar thermal expansion. ReliaCoat has preliminary experience in this area.; (2) Multicomponent rare-earth silicates, which have recently been shown by our collaborator Dr. Padture to serve both as an EBC and a TBC through intrinsically low thermal conductivities. We have partnered with Oerlikon Metco to produce specialized chemistries of silicate oxides.; (3) Functional grading, layering and optimal microstructure as appropriate to address any thermal stress issues as well as surface protection needs. Here novel processing approaches are envisaged.; (4) High temperature simulated H2 atmosphere furnace cycle tests conducted in conjunction with Dr. Mackenize Ridley and Dr. Bruce Pint at Oak Ridge National Lab with future burner rig developments at ReliaCoat Technologies.; and (5) Novel H2-O2 high heat flux burner rig capability being brought online by RCT will provide ability to rapidly screen coatings and insights into realistic performance in combustion environments. Commercial applications and other benefits include transferring the resulting thermal/environmental barrier coatings solution to engine and coatings manufacturers for implementation in future highly efficient gas-turbine engines as well as spill off opportunities in aviation engines.