Oxygen Plasma Treatment for Silicate Thermal Coating Adhesion
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Solution Overview
Problem
Silicate-based thermal control coatings face challenges in adhesion to substrates due to interlaminar stress and thermal expansion mismatches, limiting their application to rigid substrates and requiring precise thickness control to avoid debonding and particle contamination, especially on complex hardware configurations.
Innovation Solution
A method involving a primer layer with an epoxy binder and silica filler, treated with oxygen plasma to increase surface area and adhesion, allowing silicate coatings to be applied on flexible substrates and thicker coatings without compromising structural integrity, using techniques like spraying or roll coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If coating thickness is increased to achieve greater solar reflectance, then optical performance is improved, but interlaminar stress increases causing debonding and particle contamination
Solution Approach 1:
The substrate surface is treated with oxygen plasma before applying the silicate coating to create a more adherent surface. This preliminary treatment modifies the substrate surface energy and morphology, enabling better bonding of thicker coatings before they are applied, thus preventing debonding even when increased thickness is required for optical performance
Solution Approach 2:
The invention changes the physical and chemical parameters of the substrate surface through plasma treatment, including surface energy, roughness, and chemical composition. These parameter changes enable the substrate to support thicker silicate coatings by improving the fundamental adhesion properties, allowing the coating to achieve greater solar reflectance without compromising reliability
2Illumination intensity
If coating thickness is increased beyond 0.005 inch, then solar reflectance is improved, but structural sturdiness is compromised by excessive interlaminar stresses
Solution Approach 1:
Oxygen plasma treatment is applied to the substrate surface before coating to pre-condition the surface for enhanced adhesion. This preliminary action creates surface characteristics that can withstand the interlaminar stresses generated by thicker coatings, maintaining structural sturdiness even when thickness exceeds conventional limits for improved solar reflectance
Solution Approach 2:
The oxygen plasma-treated surface acts as an intermediary layer between the substrate and the silicate coating. This treated surface provides improved bonding characteristics that mediate the stress transfer, allowing thicker coatings to maintain structural integrity by distributing interlaminar stresses more effectively across the interface
3Reliability
If epoxy binder is used to enable adhesion of silicate coatings, then adhesion to substrates is improved, but adhesion strength is still insufficient for thicker coatings on complex hardware configurations
Solution Approach 1:
The substrate surface undergoes oxygen plasma treatment before applying the epoxy binder and silicate coating. This preliminary surface modification enhances the effectiveness of the epoxy binder by creating a higher energy, more reactive surface that improves wetting and bonding, providing sufficient adhesion strength even for thicker coatings on complex hardware configurations with varying surface geometries
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 oxygen plasma treatment enhances adhesion strength by over 40%, enabling silicate coatings to be used on flexible substrates and increasing the safe application thickness, reducing debonding risks and improving heat rejection performance.
Implementation Method 1
treating the exposed surface with an oxygen plasma to oxidize the exposed surface
Implementation Method 2
The treatment with oxygen plasma can increase a surface area of the exposed surface
Implementation Method 3
applying a silicate-based thermal control coating material to the treated surface under conditions such that the silicate-based thermal control coating material chemically bonds to the treated surface
Data Source
AI summary
A method of making a thermal control coating is provided. A primer layer can be applied to a substrate to form an exposed surface. The primer layer can include an epoxy binder and a silica filler. The exposed surface can be treated with an oxygen plasma to form a treated surface. A silicate-based thermal control coating can be applied to the treated surface, for example, by spraying, to form a thermal control coating on the substrate. Spacecraft and spacecraft hardware components coated with the thermal control coating, are also provided.