Multi-Layered Ceramic Barrier Coating with Columnar Microstructure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming multi-layered ceramic barrier coatings for gas turbine engine components fail to effectively manage the severe conditions of high temperatures and corrosiveness, particularly in achieving optimal microstructural properties for thermal and environmental resistance.
Innovation Solution
A method involving electron beam physical vapor deposition (EB-PVD) is used to form a multi-layered ceramic barrier coating by modulating electron beam power and focus to produce specific evaporating energies and microstructures, with low-dopant and high-dopant ceramic materials being deposited in columnar and branched columnar microstructures respectively, under controlled chamber pressures and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-layer ceramic barrier coatings are used, then the coating process is simple, but the coating cannot provide sufficient thermal and environmental resistance under severe high-temperature conditions
Solution Approach 1:
The coating system is divided into multiple distinct layers: a first ceramic barrier coating layer with columnar microstructure and a second ceramic barrier coating layer with branched columnar microstructure. Each layer provides specific protective functions, with the first layer offering baseline thermal barrier properties and the second layer enhancing environmental resistance and strain tolerance through its branched microstructure.
Solution Approach 2:
The invention uses composite ceramic materials with different dopant concentrations - a first ceramic material with a first dopant concentration for the first layer and a second ceramic material with a second dopant concentration for the second layer. This composite approach allows optimization of each layer's properties for specific functional requirements under severe service conditions.
2Strength
If electron beam power is increased to improve coating density and adhesion, then coating strength improves, but excessive power causes material degradation and loss of microstructural control
Solution Approach 1:
The electron beam parameters are dynamically adjusted during the deposition process - beam current, beam voltage, and scanning speed are varied to optimize both coating density and microstructural formation. This dynamic control allows the process to achieve high adhesion and density while maintaining precise control over the columnar and branched columnar microstructures.
Solution Approach 2:
Different electron beam parameters are used for depositing the first and second ceramic layers. The beam current, voltage, and scanning patterns are specifically tuned to produce the desired columnar microstructure in the first layer and branched columnar microstructure in the second layer, while maintaining optimal coating density and adhesion without material degradation.
3Reliability
If dopant concentration is increased to improve coating stability and corrosion resistance, then environmental resistance improves, but the coating becomes more susceptible to strain and microstructure degradation
Solution Approach 1:
Different dopant concentrations are applied locally to different layers based on their specific functional requirements. The first ceramic layer uses a first dopant concentration optimized for providing baseline stability and corrosion resistance, while the second ceramic layer uses a second dopant concentration optimized for enhancing strain resistance and environmental durability. This local optimization resolves the contradiction between corrosion resistance and strain resistance.
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 results in a coating with enhanced thermal and environmental resistance, strength, and strain resistance, providing a more effective barrier against high-temperature corrosive conditions by optimizing the microstructural properties of the ceramic layers.
Implementation Method 1
evaporating a ceramic material to deposit the ceramic material on the substrate
Implementation Method 2
electron beam physical vapor deposition (EB-PVD) is used to form a multi-layered ceramic barrier coating
Implementation Method 3
modulating a first percentage of an electron beam power that is on a pool of the low-dopant ceramic material to produce the first input evaporating energy
Data Source
Figure 1~3B
Figure 4
Figure 5~7
AI summary
A method includes forming a multi-layered ceramic barrier coating (64) under a chamber pressure of greater than 1 Pascals. In the method, low- and high-dopant ceramic materials are evaporated using input evaporating energies that fall, respectively, above and below a threshold for depositing the materials in a columnar microstructure (70) (low-dopant) and in a branched columnar microstructure (72) (high-dopant).