Molded CMC Coating Using Flexible Molds for Surface Smoothing
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Solution Overview
Problem
Existing methods for applying coatings to ceramic matrix composite (CMC) components in gas turbine engines fail to effectively smooth the rough surfaces of CMCs, leading to negligible smoothing effects and maintaining surface roughness, which affects aerodynamic performance.
Innovation Solution
A coating system using a flexible silicone mold with a defined mold cavity and coating gap to apply a molding slurry that smooths the CMC surface by filling and solidifying within the gap, followed by consolidation to form a final coating with reduced roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a coating is deposited over the as-formed surface of a CMC component, then the coating serves to somewhat smooth over the roughness, but the smoothing effect is negligible and the coating mostly conforms to the underlying rough surface
Solution Approach 1:
The patent applies preliminary action by preparing the CMC component surface through blasting or etching before coating application. This pre-treatment creates a controlled rough surface that enhances coating adhesion and allows for better smoothing effects during the subsequent coating process, thereby improving manufacturing precision while maintaining ease of manufacture.
Solution Approach 2:
The patent introduces an intermediary layer or intermediate treatment between the rough CMC surface and the final coating. This intermediary step, such as a primer or surface modification layer, acts as a mediator that fills in the roughness valleys and provides a more uniform base for the coating, achieving better surface smoothness without complicating the overall manufacturing process.
2Manufacturing precision
If existing coating methods are used on CMC components, then the coating can be applied, but the surface roughness is maintained and aerodynamic performance is affected
Solution Approach 1:
The patent applies parameter changes by modifying the coating application parameters, such as controlling the coating thickness, application speed, and curing conditions. These parameter adjustments enable the coating to effectively smooth the surface while maintaining structural integrity and aerodynamic performance, thereby improving both manufacturing precision and reliability simultaneously.
Solution Approach 2:
The patent replaces traditional mechanical coating methods with alternative approaches such as centrifugal casting or controlled deposition techniques. These substituted methods provide better control over coating uniformity and surface smoothness, improving aerodynamic performance while maintaining reliable coating application.
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 method achieves a final coating with surface roughness less than 200 Ra, significantly reducing the reproduction of underlying roughness and enhancing aerodynamic performance.
Implementation Method 1
The flexible wall is compressed to a degree that facilitates removal of the mold from the component
Implementation Method 2
Either a molding slurry or a solidified molding slurry fills the coating gap
Data Source
AI summary
A coating system includes a mold having a flexible wall defining a mold cavity, a component disposed in the mold cavity, there being a coating gap defined between the component and the flexible wall of the mold cavity, and either a molding slurry or a solidified molding slurry filling the coating gap.