Thermal Barrier Coating Reduces Thermal Conductivity
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Solution Overview
Problem
Conventional thermal barrier coatings for high-temperature applications, such as gas turbines and jet engines, face challenges in achieving superior thermal insulation without increasing film thickness, which can lead to cracking and peeling due to high thermal conductivity and phase transitions.
Innovation Solution
Development of thermal barrier coating materials represented by compounds like Ln1-xTaxO1.5+x and Ln1-xNbO1.5+x, where Ln represents Sc, Y, and lanthanoid elements, with specific ion radius and composition ranges, that exhibit lower thermal conductivity through increased phonon scattering from oxygen defects, preventing phase transitions and maintaining mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of the thermal barrier coating is increased to enhance thermal barrier properties, then the thermal insulation performance is improved, but the film becomes more susceptible to cracking and peeling
Solution Approach 1:
The invention changes the material composition parameters by incorporating specific ratios of Ta2O5 (0.1-0.25 mol) and Nb2O5 (0.1-0.25 mol) into the rare earth stabilized zirconia base material. This compositional parameter change reduces thermal conductivity to approximately half that of conventional YSZ, enabling superior thermal barrier performance at reduced film thickness and preventing cracking/peeling issues
Solution Approach 2:
The invention creates a composite thermal barrier coating material combining rare earth stabilized zirconia with tantalum oxide and niobium oxide in specific proportions. This composite structure achieves both low thermal conductivity and high mechanical stability, resolving the contradiction between thermal insulation performance and crack resistance
2Loss of energy
If conventional rare earth stabilized zirconia is used as thermal barrier coating, then the material has good phase stability and toughness, but the thermal conductivity is too high (2.2 W/mK) to achieve superior thermal barrier properties without increasing thickness
Solution Approach 1:
The invention modifies the chemical composition parameters of the thermal barrier coating by adding specific amounts of Ta2O5 (0.1-0.25 mol) and Nb2O5 (0.1-0.25 mol) to the rare earth stabilized zirconia base material. This compositional adjustment reduces thermal conductivity to approximately 1.1 W/mK (half of conventional YSZ) while maintaining phase stability through the controlled composition ranges
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
These materials provide superior thermal barrier properties with reduced thermal conductivity, preventing cracking and peeling, even at rapid temperature changes, thus enhancing the durability of metal components in high-temperature environments without the need for increased film thickness.
Implementation Method 1
exhibits a low thermal conductivity... increased phonon scattering from oxygen defects
Implementation Method 2
preventing phase transitions and maintaining mechanical stability
Implementation Method 3
a thermal barrier coating (TBC) is applied to the surface of the components... the multitude of the above types of pores that exist inside the material help maintain the thermal insulation performance
Data Source
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AI summary
A thermal barrier coating material having a lower thermal conductivity than rare earth stabilized zirconia materials. A thermal barrier coating material comprising mainly a compound represented by composition formula (1): Ln1-xTaxO1.5+x wherein 0.13≤x≤0.24, and Ln represents one or more elements selected from the group consisting of Sc, Y and the lanthanoid elements. Also, a thermal barrier coating material comprising mainly a compound represented by composition formula (2): Ln1-xNbxO1.5+x wherein 0.13≤x≤0.24, and Ln represents one or more elements selected from the group consisting of Sc, Y and the lanthanoid elements. Also, a thermal barrier coating material comprising mainly a cubic compound having a fluorite structure represented by composition formula (3): Ln3NbO7 wherein Ln represents one or more elements selected from the group consisting of Sc, Y and the lanthanoid elements.