Composite-Metal Joint Barrier Sealing Against Galvanic Corrosion
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Solution Overview
Problem
Joining dissimilar materials like composite and metal components in structures, such as aircraft, leads to corrosion issues due to electrical potential differences, especially when moisture is present, causing galvanic corrosion and degradation of mechanical properties.
Innovation Solution
A joining assembly that positions a composite component with a barrier and edge seal to isolate it from a metal component, creating sealed chambers to prevent moisture contact and electrical isolation, using materials like titanium or titanium alloys for the barrier and sealants like silicone-based polymers to inhibit corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If dissimilar materials (composite and metal) are joined directly, then structural properties of both materials are utilized, but galvanic corrosion occurs due to electrical potential difference when moisture is present
Solution Approach 1:
A barrier component made of corrosion-resistant material (e.g., titanium) is introduced between the composite and metal components. This intermediary barrier electrically isolates the dissimilar materials, preventing galvanic corrosion while allowing both materials to contribute their structural properties to the joint assembly.
Solution Approach 2:
The joint assembly is divided into distinct separated zones: a first chamber containing the composite component and a second chamber containing the metal component, with the barrier creating physical and electrical separation. This segmentation prevents direct contact between dissimilar materials while maintaining structural integrity.
2Adaptability or versatility
If moisture is allowed to remain in contact with joined components, then joint flexibility is maintained, but corrosion and degradation of mechanical properties occur
Solution Approach 1:
The joint assembly is segmented into separate sealed chambers - a first chamber for the composite component and a second chamber for the metal component. This segmentation allows each chamber to be sealed independently against moisture ingress while maintaining the overall flexibility and adaptability of the joint assembly.
Solution Approach 2:
The barrier and sealant system creates an inert, moisture-excluded environment within the sealed chambers. By preventing moisture contact through the barrier and edge seals, the chambers maintain a protective atmosphere that prevents corrosion and degradation of mechanical properties.
3Reliability
If barrier and sealant systems are added to prevent corrosion, then corrosion resistance is improved, but device complexity increases
Solution Approach 1:
The barrier component and edge sealant system are integrated into a unified joining assembly structure. The barrier is positioned between the components and the sealant covers the edges, merging these protective elements into a single coordinated system that prevents corrosion without requiring multiple separate complex components.
Solution Approach 2:
The sealant system uses flexible sealing materials that conform to the edges of the components and barrier. These thin film-like sealants provide effective moisture protection while adding minimal structural complexity to the joining assembly.
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
Effectively reduces corrosion of metal components by preventing moisture contact and electrical interaction, extending the service life of the joined components and reducing maintenance costs.
Implementation Method 1
When dissimilar materials are to be joined, such as a component made from a composite material joined to a component made from a metal such as, for example, aluminum, a large difference in electrical potential is created. Such differential in electrical potential can increase the probability of corrosion of, for example, aluminum, especially when oriented proximate to composite components having exposed carbon fibers edges.
Implementation Method 2
a large difference in electrical potential is created. Such differential in electrical potential can increase the probability of corrosion
Implementation Method 3
Any flaws in the edges or ends of the composite material or the sealant covering the edges or ends can exacerbate the collection of, or otherwise serve as sites to retain moisture that may build up within joints used to connect the components
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
Methods, systems and apparatuses are disclosed for joining assemblies, particularly joints and joining assemblies for co-joining composite components and metal components in a joining assembly, and inhibiting corrosion of metal components secured to composite component via a joining assembly.