SPS Outer Layer for Thermal Barrier Coating Impact Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engine components face durability issues due to particulate debris impacts, which can reduce the effectiveness and lifespan of thermal barrier coatings (TBCs) by causing abrasion or fracture.
Innovation Solution
A suspension plasma sprayed (SPS) outer layer with varying composition and structure is applied over the TBC, designed to deform, crush, or liberate upon impact, acting as an energy-absorbing sacrificial layer to prevent damage to the underlying TBC, using materials like zirconia-based ceramics or hafnia, and applied using multiple coating passes with different parameters and compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal barrier coating is applied to protect components from thermal fatigue, then the component can operate at higher temperatures, but the TBC becomes vulnerable to particulate debris impact causing abrasion or fracture
Solution Approach 1:
A suspension plasma sprayed outer layer is applied over the thermal barrier coating before impact events occur. This outer layer is designed to deform, crush, or liberate upon impact, acting as a sacrificial cushion that absorbs impact energy and prevents damage to the underlying TBC, thereby resolving the contradiction between maintaining high temperature operation and ensuring impact durability.
2Reliability
If the outer layer is designed to deform and crush upon impact to absorb energy, then impact resistance is improved, but the outer layer material is consumed or liberated
Solution Approach 1:
The outer layer is designed as a sacrificial, disposable element that is intended to be consumed during impact events. By using a suspension plasma sprayed outer layer with controlled composition and structure, the system accepts that some material will be liberated upon impact, but this loss is acceptable because it protects the more critical underlying TBC. The outer layer can be replenished through maintenance coating applications.
Solution Approach 2:
The outer layer is designed with specific material parameters (composition, porosity, toughness) that enable it to deform and crush in a controlled manner upon impact. By adjusting these parameters, the outer layer absorbs impact energy through deliberate material transformation, accepting controlled material loss while protecting the underlying structure.
3Reliability
If suspension plasma spray technique is used to apply the outer layer with varied composition, then impact energy absorption is improved, but the coating process complexity increases
Solution Approach 1:
The suspension plasma spray technique enables precise control of material parameters during the coating process. By varying suspension composition, spray parameters, and deposition conditions, the outer layer is built with controlled variations in porosity, density, and composition that optimize impact energy absorption. This parameter control is achieved through the plasma spray process itself, which naturally creates a splat-based microstructure with inherent porosity and bonding characteristics.
Solution Approach 2:
The outer layer is applied as a composite structure with varied composition and microstructure throughout its thickness. The suspension plasma spray technique deposits multiple splats with different orientations, porosities, and material compositions, creating a composite material system that optimizes impact resistance. This composite structure absorbs impact energy through multiple mechanisms including crack deflection, pore collapse, and material deformation.
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 SPS outer layer effectively absorbs and dissipates impact energy, preventing crack initiation and chip formation in the TBC, enhancing the component's resistance to both high and low energy impact events and extending its lifespan.
Implementation Method 1
The outer layer can be deposited over the TBC using any suitable technique, including, but not limited to, a suspension plasma spray (SPS) technique
Implementation Method 2
The material of the outer layer is lower density material such that the outer layer is deformed in response to an impact event between the particulate debris and the outer layer
Data Source
Figure 1
Figure 2~4
AI summary
A component according to an exemplary aspect of the present disclosure includes, among other things, a substrate, a thermal barrier coating deposited on at least a portion of the substrate, and an outer layer deposited on at least a portion of the thermal barrier coating. The outer layer includes a material that absorbs energy in response to an impact event along at least a portion of the outer layer.