Composite Thermal Barrier Coating Impact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thermal barrier coatings (TBCs) used in gas turbine engines are susceptible to impact spallation and erosion, leading to reduced component life and engine performance, despite previous advancements in dispersion-hardening techniques.
Innovation Solution
A composite thermal barrier coating is developed, featuring ceramic reinforcement particles with a yield strength greater than the ceramic matrix material, dispersed throughout the coating to provide crack blunting and deflection, and deposited using physical vapor deposition or plasma spraying, with particles larger than five micrometers in size to enhance impact and erosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If YSZ TBC is used for thermal insulation, then thermal barrier performance is improved, but impact and erosion resistance deteriorates
Solution Approach 1:
The patent applies composite materials by combining YSZ matrix material with dispersed ceramic particles (alumina, silica, or titania) having different mechanical properties. The ceramic particles act as reinforcement phase while YSZ provides thermal insulation, creating a composite structure that simultaneously achieves thermal barrier performance and improved impact/erosion resistance through particle dispersion and crack deflection mechanisms
2Strength
If fine precipitates or particles (up to five micrometers) are dispersed in TBC, then dispersion hardening effect is achieved, but impact spallation resistance remains insufficient
Solution Approach 1:
The patent changes the particle size parameter from fine precipitates (up to 5 micrometers) to larger ceramic particles (5-50 micrometers). This parameter change transforms the reinforcement mechanism from dispersion hardening to crack deflection and blunting, where larger particles more effectively intercept and deflect cracks, thereby improving impact spallation resistance while maintaining dispersion strengthening benefits
3Productivity
If TBC is deposited by plasma spraying with molten splats, then deposition efficiency is improved, but microstructure homogeneity deteriorates
Solution Approach 1:
The patent utilizes the inherent porosity and splat structure from plasma spraying but controls and optimizes it by dispersing ceramic particles throughout the matrix. The particles are incorporated during the splat formation process, creating a composite microstructure where the porosity provides thermal insulation while the dispersed particles maintain compositional homogeneity and prevent excessive grain coarsening
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composite TBC exhibits significant improvements in impact spallation resistance and erosion resistance, with results showing up to 100% improvement in impact spallation resistance and comparable erosion resistance to control specimens, through the use of larger ceramic reinforcement particles.
Implementation Method 1
Improved impact and erosion resistance is believed to be attributable at least in part to the particles providing crack blunting and crack deflection that inhibit crack propagation through the ceramic matrix material
Implementation Method 2
deposited using physical vapor deposition or plasma spraying
Implementation Method 3
deposited using physical vapor deposition or plasma spraying
Data Source
AI summary
A thermal barrier coating (TBC) for a component intended for use in a hostile environment, such as a component of a gas turbine engine. The TBC exhibits improved impact and erosion resistance as a result of being a composite material consisting essentially of particles of a ceramic reinforcement material dispersed in a ceramic matrix material. The ceramic reinforcement material has a yield strength greater than the ceramic matrix material at about 1100° C., and the particles of the ceramic reinforcement material have an average maximum dimension of greater than five micrometers.