High Temperature Coating for Carbon-Carbon Composite Substrates
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Solution Overview
Problem
Carbon-carbon composite components in space vehicles are susceptible to high temperatures, leading to oxidation and degradation of physio-mechanical properties, and lack sufficient thermal radiation due to low emissivity, which can result in overheating and failure during space travel.
Innovation Solution
A high-temperature coating comprising a crystallized metal carbide undercoat and a high emissivity overcoat layer, including a complex oxide, is applied to the carbon-carbon composite substrates to enhance radiative cooling and protect against oxidation, with the overcoat layer having a higher emissivity than the undercoat to improve thermal radiation and maintain component temperatures below failure thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a carbon-carbon composite substrate is used for high temperature applications, then it can withstand high temperatures structurally, but it is susceptible to oxidation and degradation of physio-mechanical properties
Solution Approach 1:
The patent applies a multi-layer composite coating system on carbon-carbon composite substrates. The first layer includes a porous ceramic material (such as silicon carbide or silicon oxide) that provides oxidation protection, while the second layer includes a metal carbide (such as titanium carbide, zirconium carbide, or hafnium carbide) that provides thermal barrier protection. This composite coating structure allows the substrate to withstand high temperatures while preventing oxidation and degradation of the carbon-carbon composite material.
2Loss of energy
If the carbon-carbon composite component relies on conduction or convection for heat transfer, then it can manage thermal energy in atmospheric conditions, but it is ineffective in space due to lack of atmosphere
Solution Approach 1:
The patent modifies the thermal radiation parameters of the carbon-carbon composite component by applying specialized coatings with controlled emissivity properties. The coating system is designed to enhance radiative heat transfer by optimizing the emissivity in the infrared spectrum, allowing the component to effectively dissipate thermal energy through radiation in the vacuum of space where conduction and convection are unavailable.
3Reliability
If the component surface has low emissivity, then it maintains structural integrity, but it lacks sufficient thermal radiation capability leading to overheating
Solution Approach 1:
The patent employs a composite coating structure where the first layer (porous ceramic material) maintains structural integrity and protection against oxidation, while the second layer (metal carbide) is specifically designed to enhance thermal radiation capability. This composite approach allows the component to simultaneously maintain structural integrity and achieve sufficient thermal radiation for effective heat dissipation in space.
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 effectively withstands hundreds of temperature cycles, providing enhanced thermal energy dissipation, abrasion resistance, and maintaining component integrity for repeated use in extreme space environments.
Implementation Method 1
The high temperature coating also includes an overcoat which includes a high emissivity layer, which may advantageously improve radiative cooling from the component relative to an uncoated carbon-carbon composite component or a C/C component coated with only the undercoat layer. Thus, the component may be radiatively cooled during space travel.
Data Source
AI summary
A space vehicle including a structural component defining a carbon-carbon composite substrate. A high temperature coating on a surface of the carbon-carbon composite substrate. The high temperature coating includes a crystallized metal carbide undercoat on and an overcoat on a surface of the undercoat. The overcoat includes a high emissivity layer. The high emissivity layer has a higher emissivity than the crystallized metal carbide undercoat, and the high emissivity layer includes a complex oxide.