Ceramic Hollow Microsphere Barrier Coating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ceramic thermal barrier coatings are not well-suited for ceramic components due to mismatched coefficients of thermal expansion and high thermal conductivity, which can lead to spallation and microcracking when exposed to high-temperature gases.
Innovation Solution
A thermal and environmental barrier coating composed of ceramic hollow microspheres with a high void volume fraction and closed porosity, sintered together with a binder or embedded in a matrix, providing low thermal conductivity and matching the coefficient of thermal expansion of the ceramic substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ceramic thermal barrier coatings are applied to ceramic substrates, then thermal protection is provided, but thermal stresses cause spallation and microcracking due to mismatched coefficients of thermal expansion
Solution Approach 1:
The patent changes the physical and chemical parameters of the coating material by incorporating hollow microspheres, which fundamentally alters the coefficient of thermal expansion to match the ceramic substrate. This parameter change eliminates the thermal stress mismatch that causes spallation and microcracking in traditional coatings.
Solution Approach 2:
The patent uses composite materials by combining hollow microspheres with binder materials to create a coating with tailored thermal expansion properties. The composite structure allows the coating to match the substrate's coefficient of thermal expansion while maintaining thermal barrier functionality.
2Temperature
If traditional ceramic thermal barrier coatings are used, then thermal protection is achieved, but thermal conductivity remains high leading to heat flow into the metal component
Solution Approach 1:
The patent employs porous materials by incorporating hollow microspheres with high void volume fractions (60-95%) into the coating. The air-filled hollow spaces act as thermal insulators, dramatically reducing thermal conductivity and minimizing heat flow to the underlying substrate.
Solution Approach 2:
The patent changes the thermal conductivity parameter by introducing hollow microspheres with low thermal conductivity into the coating matrix. This fundamentally alters the heat transfer properties, reducing thermal conductivity from typical values of 0.8-1.6 W/mK to significantly lower values.
3Temperature
If hollow microspheres with high void volume fraction are used to reduce thermal conductivity, then thermal insulation is improved, but coating density decreases
Solution Approach 1:
The patent intentionally uses porous materials with high void volume fractions (60-95%) to achieve superior thermal insulation. The hollow microspheres create a lightweight, low-density structure that maximizes thermal resistance while maintaining coating integrity through the binder material.
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 coating achieves significantly reduced thermal conductivity and improved cyclic durability by minimizing thermal stresses and matching the thermal expansion of the ceramic substrate, while maintaining high temperature capability and resistance to water vapor corrosion.
Implementation Method 1
The thermal and environmental barrier coating may have low conductivity as a result of including the hollow microspheres
Implementation Method 2
with a low coefficient of thermal expansion similar to the ceramic substrate
Implementation Method 3
the microspheres are sintered together with a powder of another material that acts as a binder
Data Source
Figure 1A~1E
Figure 2A~2C
Figure 3A~3C
AI summary
A thermal and environmental barrier coating composed of ceramic hollow microspheres sintered together. In one embodiment the microspheres are sintered together with a powder of another material that acts as a binder, or with a powder of a material that may be the same as the material of the hollow microspheres, forming a matrix in which the hollow microspheres are embedded. The hollow microspheres may be composed of a material with a high temperature capability, and with a low coefficient of thermal expansion.