Multi-Stabilizer Thermal Barrier Coatings for Turbine Engines
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Solution Overview
Problem
Conventional thermal barrier coatings for turbine engine components face limitations in high-temperature applications due to low fracture toughness and high thermal conductivity, which affect their cyclic life, erosion resistance, and corrosion resistance.
Innovation Solution
A thermal barrier coating composed of a tantala-zirconia mixture stabilized with two or more stabilizers, such as yttria, ytterbia, and gadolinia, is developed to enhance fracture toughness, thermal insulation, and corrosion resistance, using physical vapor deposition or plasma spray techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If advanced ceramic TBCs such as lanthanide-base oxides (Gd2Zr2O7, Nd2Zr2O7) or fully-stabilized cubic zirconia (20YSZ) are used to reduce thermal conductivity and improve thermal insulation, then thermal insulation performance is improved, but fracture toughness significantly decreases
Solution Approach 1:
The patent applies composite materials by combining multiple oxide components (lanthanide-base oxides A2B2O7, zirconia ZrO2, and yttria Y2O3) to create a multi-phase ceramic coating. This composite structure allows the coating to simultaneously achieve low thermal conductivity from the lanthanide phases and adequate fracture toughness from the zirconia and yttria phases, resolving the contradiction between thermal insulation and mechanical strength.
Solution Approach 2:
The patent changes the chemical composition parameters by specifying precise mole percentage ranges for each oxide component (A2B2O7: 20-40%, ZrO2: 30-50%, Y2O3: 10-30%). By optimizing these compositional parameters, the coating achieves a balance between thermal insulation (low thermal conductivity) and fracture toughness, allowing operation at temperatures up to 2200°F while maintaining structural integrity.
2Strength
If conventional TBCs such as 7YSZ are used to maintain adequate fracture toughness, then mechanical strength is preserved, but thermal conductivity increases reducing thermal insulation effectiveness
Solution Approach 1:
The patent replaces conventional single-phase 7YSZ material with a multi-phase composite containing lanthanide-base oxides (A2B2O7), zirconia (ZrO2), and yttria (Y2O3). The lanthanide phases provide low thermal conductivity for superior thermal insulation, while the zirconia and yttria phases contribute to fracture toughness, achieving both low thermal conductivity and adequate mechanical strength simultaneously.
Solution Approach 2:
The patent fundamentally changes the material composition from conventional 7YSZ (6-8 wt% yttria-stabilized zirconia) to a multi-component oxide system with controlled mole percentages. This compositional transformation enables the coating to achieve thermal conductivity suitable for high-temperature applications (up to 2200°F) while maintaining fracture toughness through the synergistic effect of multiple phases.
3Duration of action of stationary object
If TBC cyclic life and erosion resistance are improved by using 7YSZ with adequate fracture toughness, then durability is enhanced, but thermal insulation performance is insufficient for higher temperature ranges
Solution Approach 1:
The patent uses a composite ceramic coating system comprising lanthanide-base oxides (A2B2O7), zirconia (ZrO2), and yttria (Y2O3) to achieve both improved thermal insulation for high-temperature operation (up to 2200°F) and adequate fracture toughness for enhanced cyclic life and erosion resistance. The multi-phase structure provides synergistic properties that single-phase materials cannot achieve alone.
4Use of energy by moving object
If the operating temperature of turbine components is increased to improve fuel efficiency, then energy efficiency is improved, but oxidation and corrosion resistance decreases due to material degradation
Solution Approach 1:
The patent applies a composite ceramic thermal barrier coating (A2B2O7-ZrO2-Y2O3) over the metallic turbine component to provide a protective barrier against oxidation and corrosion at elevated operating temperatures (up to 2200°F). This coating system enables the turbine to operate at higher temperatures for improved fuel efficiency while the coating protects the underlying metal from oxidative and corrosive degradation.
Solution Approach 2:
The thermal barrier coating acts as an intermediary protective layer between the hot combustion gases and the turbine component. This coating barrier shields the metal substrate from direct exposure to corrosive and oxidizing combustion environments, enabling high-temperature operation for improved fuel efficiency while maintaining material reliability and preventing degradation.
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 multi-stabilizer thermal barrier coating achieves improved thermal insulation, fracture toughness, and corrosion resistance, enabling operation at extreme temperatures while maintaining structural stability and reducing thermal conductivity compared to conventional coatings.
Implementation Method 1
These more advanced ceramic TBCs have lower thermal conductivity and, therefore, may provide better thermal insulation as compared to 7YSZ
Implementation Method 2
a layer of 6-8 weight percent yttria-stabilized zirconia (7YSZ) deposited by an electron beam physical vapor deposition (EB-PVD) process
Implementation Method 3
a layer of 6-8 weight percent yttria-stabilized zirconia (7YSZ) deposited by an electron beam physical vapor deposition (EB-PVD) process or by plasma spray
Data Source
AI summary
Thermal barrier coatings consist of a tantala-zirconia mixture that is stabilized with two or more stabilizers. An exemplary thermal barrier coating consists of, by mole percent: about 8% to about 30% YO1.5; about 8% to about 30% YbO1.5 or GdO1.5 or combination thereof; about 8% to about 30% TaO2.5; about 0% to about 10% HfO2; and a balance of ZrO2.