Variable Ceramic Coating Thickness for Turbine Blade Heat Protection
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Solution Overview
Problem
Current ceramic coating processes for turbomachinery components, such as EBPVD, fail to optimize thermal resistance due to uniform thickness application, leading to issues like thermal spallation and CMAS attack, which are dominated by interface and surface temperatures, respectively.
Innovation Solution
A method involving variable rotation rates during coating application to achieve different thicknesses of ceramic layers on different parts of turbomachinery components, particularly the suction and pressure sides of blades and vanes, using materials like YSZ and GZO to enhance durability and thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If uniform thickness coating is applied to all parts of the component, then manufacturing simplicity is maintained, but thermal resistance optimization is prevented due to varying thermal requirements on different surfaces
Solution Approach 1:
The patent applies different coating thicknesses to different regions of the component based on local thermal requirements. The suction side receives a first coating thickness optimized for its thermal conditions, while the pressure side receives a second coating thickness optimized for its different thermal conditions. This local quality approach allows thermal resistance optimization without requiring complex multi-step coating processes, as the variable thickness is achieved through a single controlled coating application.
2Object-affected harmful factors
If thicker coating is applied to the pressure side, then CMAS attack resistance is improved, but thermal spallation resistance deteriorates due to excessive thickness increasing interface temperature
Solution Approach 1:
The patent applies a thicker coating specifically to the pressure side where CMAS attack occurs, while maintaining a thinner coating on the suction side where thermal spallation is the primary concern. This localized thickness variation allows the pressure side to benefit from enhanced CMAS resistance through increased coating thickness, while the suction side maintains lower interface temperatures to prevent thermal spallation.
Solution Approach 2:
The patent creates an asymmetric coating thickness distribution across the component surfaces, with the pressure side having a different coating thickness than the suction side. This asymmetry is driven by the different damage mechanisms affecting each surface: the pressure side requires thicker coating for CMAS protection, while the suction side requires thinner coating for thermal spallation prevention.
3Strength
If thinner coating is applied to the suction side, then thermal spallation resistance is improved by reducing interface temperature, but CMAS attack protection deteriorates if deposits occur on this surface
Solution Approach 1:
The patent applies a thinner coating thickness specifically to the suction side to reduce the interface temperature and prevent thermal spallation, while applying a thicker coating to the pressure side for CMAS protection. This localized thickness optimization ensures each surface has the coating thickness appropriate for its primary damage mechanism.
4Manufacturing precision
If variable rotation rates are used during coating application, then coating thickness precision is improved for different surfaces, but manufacturing complexity increases
Solution Approach 1:
The patent employs dynamic variation of the rotation rate during the coating application process. The rotation rate is adjusted based on which surface is currently being coated: a first rotation rate is used when the suction side faces the coating source, and a second rotation rate is used when the pressure side faces the source. This dynamic control enables precise thickness variation on different surfaces while maintaining a relatively simple single-step coating process.
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
This approach mitigates rapid distress from CMAS attack and thermal spallation by controlling surface and interface temperatures, enhancing the durability and thermal resistance of coatings, thereby improving the operational efficiency and lifespan of gas turbine engines.
Implementation Method 1
EBPVD (electron beam physical vapor deposition) processing
Implementation Method 2
EBPVD (electron beam physical vapor deposition) processing
Implementation Method 3
electron beam physical vapor deposition processing
Data Source
AI summary
A method for coating a part includes the steps of mounting a part for rotation relative to a source of coating material; and rotating the part relative to the source of coating material at variable rates of rotation within a single rotation, whereby different portions of the part are coated at a different thickness.