CMAS-Resistant Protective Layer for Turbine Stability
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Solution Overview
Problem
Existing CMAS-resistant protective layers in aerospace turbines are not stable in the long term and allow infiltration of CMAS at high temperatures, leading to thermal instability and frequent layer degradation.
Innovation Solution
A protective layer composed of iron oxide, yttrium oxide, and silicon oxide, with specific atomic percentage ranges, that forms a crystalline layer preventing CMAS infiltration and maintaining adhesion to thermal insulation layers, applied using various coating methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing CMAS-resistant protective layers are used, then CMAS infiltration is slowed down through chemical reaction, but the protective layer degrades and requires frequent renewal
Solution Approach 1:
The invention changes the chemical composition parameters of the protective layer by incorporating specific rare earth metals (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, or lutetium) in controlled amounts (0.1-10 wt%). This compositional parameter change enables the layer to form stable crystalline phases that resist CMAS infiltration without undergoing degradation, thus extending the service life while maintaining CMAS resistance
Solution Approach 2:
The invention creates a composite protective layer structure combining rare earth metal oxides with traditional TBC materials (such as yttria-stabilized zirconia). This composite approach leverages the high melting point and chemical stability of rare earth oxides to prevent CMAS infiltration, while the underlying TBC structure provides thermal insulation. The composite material system achieves both long-term stability and effective CMAS resistance without the degradation issues of previous single-material systems
2Object-affected harmful factors
If protective layers react with CMAS to form higher melting temperature products, then infiltration is slowed, but the protective layer degrades
Solution Approach 1:
The invention applies preliminary anti-action by pre-forming a protective surface layer with rare earth metal oxides that have inherently high chemical stability and high melting points. This pre-configured protective barrier prevents CMAS from reacting with and degrading the underlying TBC structure. The rare earth oxides serve as a stable front line that resists CMAS infiltration through physical barrier properties rather than reactive consumption, thus preventing both infiltration and degradation simultaneously
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 protective layer effectively prevents CMAS infiltration into porous structures at temperatures above 1200°C, ensuring long-term thermal stability and adhesion, reducing the need for frequent layer renewal.
Implementation Method 1
The protective layer effectively prevents CMAS infiltration into porous structures at temperatures above 1200°C
Implementation Method 2
applied using various coating methods
Data Source
AI summary
The present invention relates to a protective layer against CMAS, to a CMAS-resistant article comprising the protective layer according to the invention, and to a process for preparing a corresponding article.