Barrier Layer with Gettering Particles for Oxidation Protection
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Solution Overview
Problem
Gas turbine engine components face challenges in withstanding high temperatures, corrosive, and oxidative conditions, leading to degradation and reduced lifespan due to inadequate thermal and oxidative stability.
Innovation Solution
A barrier layer comprising a silicon dioxide matrix with diffusive and gettering particles, where the gettering particles are a reaction product of SiwOxCyNz + ξO2 = wSiO2 + yCO + zN2, providing enhanced thermal and environmental protection by limiting oxygen and moisture diffusion and preventing substrate oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective barrier coating is applied to improve thermal and oxidative stability, then the component's resistance to high temperatures and corrosive conditions is improved, but the coating complexity and manufacturing difficulty increase
Solution Approach 1:
The barrier coating is designed as a composite material system consisting of multiple functional layers: a bond coat layer containing gettering particles (SiC, Si3N4, SiOC) that react with oxygen and moisture, and a ceramic top coat layer (alumina, silica, mullite) that provides physical barrier protection. This composite structure achieves superior thermal and oxidative stability by combining the chemical reactivity of the bond coat with the protective barrier properties of the ceramic top coat.
Solution Approach 2:
The coating system utilizes controlled chemical reactions by changing parameters such as temperature and atmosphere during application and service. The bond coat particles are designed to undergo oxidation reactions at specific temperatures to form protective scales, while the ceramic top coat is applied in a controlled manner to create a stable barrier. These parameter-controlled reactions enable the coating to adapt to varying thermal and oxidative conditions.
2Reliability
If the barrier coating is designed with multiple functional layers and particles, then the protection against oxygen and moisture diffusion is improved, but the manufacturing precision and coating application difficulty increase
Solution Approach 1:
The protective coating is segmented into distinct functional layers: a bond coat layer with gettering particles that chemically react with oxidants, and a separate ceramic top coat layer that provides physical barrier protection. This segmentation allows each layer to be optimized for its specific function and applied using appropriate processes, reducing the overall manufacturing precision requirements compared to a single complex layer.
Solution Approach 2:
The bond coat acts as an intermediary layer between the substrate and the ceramic top coat. It contains gettering particles that chemically interact with oxygen and moisture, converting harmful oxidants into stable compounds. This intermediary function reduces the burden on the ceramic top coat to provide complete protection, thereby reducing the precision requirements for the top coat application.
3Reliability
If gettering particles are used to react with oxygen and moisture, then the substrate protection is improved, but the coating composition and material selection complexity increase
Solution Approach 1:
Different regions of the coating system have different compositions optimized for their local functions: the bond coat contains gettering particles (SiC, Si3N4, SiOC) specifically for chemical reaction with oxidants, while the ceramic top coat contains alumina, silica, or mullite for physical barrier protection. This local quality differentiation allows each material to be selected and applied based on its specific protective mechanism, managing overall composition complexity.
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 barrier layer effectively protects the substrate from environmental and thermal stresses, extending the component's lifespan and enabling higher operating temperatures with improved thermal efficiency.
Implementation Method 1
The composition of the gettering particles is a reaction product of the chemical reaction of Equation 1 defined by Equation 2: SiwOxCyNz + ξO2 = wSiO2 + yCO + zN2
Implementation Method 2
gettering particles disposed in the matrix... providing enhanced thermal and environmental protection by limiting oxygen and moisture diffusion and preventing substrate oxidation
Implementation Method 3
limiting oxygen and moisture diffusion
Data Source
AI summary
A barrier layer for an article according to an exemplary embodiment of this disclosure, among other possible things includes a bond coat comprising a matrix, diffusive particles disposed in the matrix, and gettering particles disposed in the matrix. The composition of the gettering particles is a reaction product of the chemical reaction of Equation 1 defined by Equation 2:SiwOxCyNz+ξO2=wSi O2+yCO+z2N2Equation 1ξ=2w+y-x2Equation 2A barrier layer is also disclosed.