Serpentine Groove Coating Interlock for Gas Turbine Durability
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Solution Overview
Problem
Existing gas turbine engine components face challenges in achieving strong bonding between substrates and coatings, particularly under high-temperature and environmental stress conditions, which affects their durability and spallation resistance.
Innovation Solution
The introduction of a serpentine groove on the substrate surface, with specific geometric features such as uniform width and depth, multiple bends, and dimples or sine wave profiles, facilitates mechanical interlocking with a coating, enhancing bonding strength and spallation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional grit-blasting is used to pre-treat the substrate surface, then the surface is cleaned and roughened to enable coating bonding, but the bond strength and spallation resistance are insufficient under high-temperature and environmental stress conditions
Solution Approach 1:
The substrate surface is segmented into multiple serpentine grooves with bends, creating a patterned structure that increases surface area and provides mechanical interlocking sites for the coating. This segmentation transforms the flat surface into a complex topography that resists spallation better than traditional grit-blasted surfaces.
Solution Approach 2:
The invention transitions from a two-dimensional flat surface to a three-dimensional patterned surface by adding serpentine grooves with bends. This dimensional change creates mechanical interlocking features that significantly improve both bond strength and spallation resistance compared to traditional two-dimensional grit-blasted surfaces.
2Strength
If the serpentine groove is made with multiple bends and specific geometric features, then mechanical interlocking with coating is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The serpentine groove pattern is implemented as a periodic, repeating structure with consistent bends and geometric features. This periodicity allows the complex groove pattern to be manufactured using standardized processes, reducing overall manufacturing complexity while maintaining the mechanical interlocking benefits.
3Reliability
If the serpentine groove is designed with uniform width and depth, then coating adherence is improved through mechanical interlocking, but the manufacturing precision requirements increase
Solution Approach 1:
The invention specifies particular parameter ranges for groove width (10-200 micrometers) and depth ratios (2:1 or less) that optimize coating adherence while remaining manufacturable. These parameter changes balance performance requirements with manufacturing feasibility, avoiding excessive precision demands.
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 serpentine groove design significantly increases bond strength by up to twice and spallation resistance by three times compared to traditional grit-blasting methods, while maintaining isotropy and hydrophilicity for improved coating adherence and durability.
Implementation Method 1
a coating disposed on the surface and mechanically interlocking with the serpentine groove
Implementation Method 2
the pre-bond surface has a Young's contact angle θY of approximately 60° and a fraction of the pre-bond surface wetted versus unwetted is at least 0.7
Data Source
AI summary
A gas turbine engine article includes a substrate that has a pre-bond surface that includes a serpentine groove. A coating is disposed on the pre-bond surface and mechanically interlocks with the serpentine groove.