Inorganic Coating Adhesion to Composite Substrates
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Solution Overview
Problem
Inorganic thermal control coatings have poor adhesion to composite materials, limiting their application to aluminum substrates, and there is a need for improved composite materials and methods to adhere these coatings to thermoplastic or thermoset substrates.
Innovation Solution
A composite structure with an inorganic coating adhered to an epoxy-based substrate using an adhesion promoting agent containing a urea moiety and an alkoxysilane moiety, which promotes tight adhesion through chemical bonding, eliminating the need for surface roughening or acid/base treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic coating materials are applied to composite materials, then thermal control capability is improved, but adhesion to the substrate deteriorates
Solution Approach 1:
The patent applies an adhesion promoter layer between the inorganic thermal control coating and the composite substrate. This intermediary layer contains silane coupling agents that chemically bond to both the inorganic coating oxides and the organic resin matrix, creating a strong interface that resolves the adhesion problem while preserving thermal control functionality.
Solution Approach 2:
The patent uses composite adhesion promoters containing both inorganic silane groups and organic functional groups. This composite molecular structure enables simultaneous bonding to inorganic coating materials and organic composite substrates, bridging the incompatibility between the two material types.
2Ease of manufacture
If traditional coating methods are used on composite materials, then application process is simplified, but coating adhesion deteriorates
Solution Approach 1:
The patent incorporates adhesion promoters into the resin matrix before composite fabrication, or applies them as a preliminary surface treatment before coating deposition. This preliminary action ensures adhesion capability is established before the coating process, eliminating the need for complex surface roughening or acid etching steps.
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 adhesion promoting agent ensures a strong, durable bond between the inorganic coating and the substrate, as demonstrated by peel tests showing less than 5% coating removal, suitable for thermal control applications in spacecraft and other structures.
Implementation Method 1
an adhesion promoting agent comprising a molecule having a urea moiety at one end of the molecule and an alkoxysilane moiety at the other end of the molecule
Implementation Method 2
The use of adhesion promoting agent having a urea moiety and an alkoxysilane moiety promotes tight adhesion of the inorganic coating to the substrate
Data Source
AI summary
The present disclosure provides a composite structure and associated method for preparing a composite substrate comprising an inorganic coating that is adhered to an organic-based substrate via an adhesion promoting agent comprising a molecule having a urea moiety at one end of the molecule and an alkoxysilane moiety at the other end of the molecule. The use of adhesion promoting agent having at least one of an amine or imine moiety and an alkoxysilane moiety promotes tight adhesion of the inorganic coating to the substrate.