ALD Multilayer Coating for Compressor Casing Wear Reduction
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Solution Overview
Problem
Casing structures in gas turbine engines, particularly those with complex geometries and non-line-of-sight surfaces like slots, face challenges in applying protective coatings due to difficulty in coating application methods.
Innovation Solution
A multi-layer coating system is applied using atomic layer deposition (ALD) with an innermost layer having high load-carrying capacity and an outermost layer with low friction, tailored to protect complex geometries and minimize wear and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods are used on complex geometries with non-line-of-sight surfaces, then coating application is difficult and incomplete, but the substrate still requires protective coating to reduce wear and friction
Solution Approach 1:
The coating is divided into multiple functional layers: an innermost layer with high load-carrying capacity for structural support, intermediate layers for transition and adhesion, and an outermost layer with low coefficient of friction for wear resistance. This segmentation allows each layer to be optimized for its specific function and enables complete coverage of complex geometries through systematic deposition
Solution Approach 2:
The patent applies atomic layer deposition (ALD) to change the deposition parameters and achieve uniform coating on non-line-of-sight surfaces. ALD enables precise control of coating thickness and composition at the atomic level, ensuring complete coverage of complex geometries including slots and recesses that are difficult to reach with conventional coating methods
2Ease of operation
If a single-layer coating is applied to provide both load-bearing and low friction properties, then coating simplicity is maintained, but the conflicting requirements of high load-carrying capacity and low friction cannot be simultaneously satisfied
Solution Approach 1:
Different regions of the coating system have different properties: the innermost layer is designed for high load-carrying capacity and structural integrity, while the outermost layer is designed for low friction and wear resistance. This local differentiation of material properties allows both conflicting requirements to be satisfied simultaneously in their respective locations within the coating system
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 coating system enhances the wear resistance and reliability of casing structures by providing uniform protection on non-line-of-sight surfaces, reducing friction and extending the lifetime of components.
Implementation Method 1
depositing an innermost layer on a substrate and depositing an outermost layer on the innermost layer by atomic layer deposition
Implementation Method 2
the innermost layer is deposited by electrodeposition or chemical vapor deposition
Implementation Method 3
the innermost layer is deposited by electrodeposition or chemical vapor deposition
Data Source
AI summary
A wear-reducing coating system for a substrate includes an innermost layer disposed on a substrate and an outermost layer disposed on the innermost layer. The innermost layer has higher load-carrying capacity than the outermost layer and the outermost layer has a lower coefficient of friction than the innermost layer. A method of applying a wear-reducing coating to a substrate and a method of applying a coating to a split ring casing for a high pressure compressor are also disclosed.