Silica-Forming Articles With Engineered Surface Ridges
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Solution Overview
Problem
High-temperature turbine engine components with silicon-containing materials face degradation due to creep displacement of thermally grown silica layers under shear loading, leading to severe damage and loss of protective coating effectiveness.
Innovation Solution
Interlocking the silicon-containing region with engineered surface features, such as ridges, to inhibit creep displacement of the environmental barrier coating system, promoting structural integrity and protection in high-temperature applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective coating system is applied to silicon-containing materials in high-temperature environments, then environmental protection is improved, but creep displacement under shear loading increases due to low viscosity of thermally grown silica
Solution Approach 1:
The invention applies preliminary action by forming engineered surface features (ridges, grooves, or dimples) on the silicon-containing material surface before applying the environmental barrier coating. These pre-formed features create an interlocking mechanism that prevents creep displacement of the thermally grown silica layer, thereby resolving the contradiction between maintaining environmental protection and preventing creep-related strength degradation.
Solution Approach 2:
The invention creates a composite structure combining the silicon-containing substrate, engineered surface features, and environmental barrier coating system. This composite approach integrates multiple functional elements: the substrate provides structural basis, the engineered features provide mechanical interlocking to resist creep, and the coating provides environmental protection, thereby simultaneously achieving both reliability and strength.
2Reliability
If thermally grown silica layer forms on silicon-containing bondcoat, then oxygen permeability is reduced, but creep rate increases under shear loading due to low viscosity
Solution Approach 1:
The engineered surface features are formed on the silicon-containing bondcoat before thermal oxidation occurs. This preliminary action ensures that when the silica layer thermally grows, it conforms to the engineered surface topology, creating an interlocking structure that prevents creep displacement while maintaining the dense, low-permeability characteristics of the thermally grown oxide.
Solution Approach 2:
The invention applies local quality by creating non-uniform surface features (ridges, grooves, or dimples) at specific locations on the bondcoat surface. These localized engineered features create areas of increased mechanical interlocking precisely where needed to prevent creep displacement, while allowing the bulk of the silica layer to maintain its protective low-permeability characteristics.
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 solution effectively reduces creep displacement and maintains the protective barrier of the environmental barrier coating system over extended high-temperature service periods, ensuring the structural integrity and longevity of turbine engine components.
Implementation Method 1
The silicon content of a silicon-containing bondcoat reacts with oxygen at high temperatures to form predominantly an amorphous silica (Si02) scale
Implementation Method 2
The amorphous silica product that forms on a silicon-containing bondcoat in service has a relatively low viscosity and consequently a high creep rate under shear loading
Data Source
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AI summary
An article includes a silicon-containing region; at least one outer layer overlying a surface of the silicon-containing region; and a constituent layer on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer, the constituent layer being formed by constituents of the silicon-containing region and being susceptible to creep within an operating environment of the article, wherein the silicon-containing region defines a pluarality of channels and a plurality of ridges that interlock within the plurality of channels are formed in the silicon-containing region to physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.