Pre-Applied Curable Sealant for Galvanic Corrosion Sealing

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Solution Overview

Problem

Sealants used in applications involving different metal compositions or a metal and a non-metallic electrically conductive material often face limitations due to galvanic corrosion when exposed to water, as they can only maintain flow characteristics for a short period, necessitating immediate application and assembly, which is not always feasible.

Innovation Solution

A method of storing curable sealants under conditions that inhibit curing, such as reduced temperature, oxygen-free, or moisture-free environments, to maintain them in an at least partially uncured state, allowing for delayed application and assembly while ensuring the sealant remains flowable for compression and subsequent curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealant is applied immediately before assembly, then the sealant maintains flow characteristics for adequate sealing, but the timeframe for application and assembly is severely limited

Engineering Contradiction:
Improvesealing qualityVSAvoidapplication timeframe
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The sealant is applied to the fastener in advance during manufacturing, before the actual assembly operation. The fastener with pre-applied sealant is then stored in controlled conditions (refrigeration at 2-8°C or freezing at -18°C or lower) to maintain the sealant in an uncured, flowable state. This allows the sealant to be ready for application without requiring immediate use, thus extending the timeframe while ensuring sealing quality when assembly occurs.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If curable sealant is stored at ambient temperature, then the sealant is readily available, but the sealant cures prematurely losing flow characteristics

Engineering Contradiction:
Improvesealant availabilityVSAvoidsealant flow characteristics
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The storage temperature parameter is changed from ambient temperature to refrigeration temperatures (2-8°C) or freezing temperatures (-18°C or lower). This parameter change slows down or stops the curing reaction of the sealant, maintaining its flow characteristics and uncured state. The sealant remains stable and available for use when needed, resolving the contradiction between availability and compositional stability.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If different metal compositions are joined without sealant, then the assembly process is simpler, but galvanic corrosion occurs due to electrochemical reactions

Engineering Contradiction:
Improveassembly processVSAvoidgalvanic corrosion
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

A curable sealant is introduced as an intermediary material between dissimilar metal components (e.g., aluminum and stainless steel). The sealant acts as a barrier that prevents direct contact between the metals and excludes water and electrolytes from the interface, thereby preventing galvanic corrosion. The sealant is applied in advance to the fastener, stored under controlled conditions to remain uncured, and then compressed during assembly to form an effective protective barrier.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This approach allows for the application of sealants at a later time, ensuring a tight seal and protection against galvanic corrosion by maintaining the sealant in a flowable state until assembly, thereby extending the timeframe for effective sealing and reducing the risk of premature curing.

Implementation Method 1

storing the curable sealant in a storage environment under conditions to maintain the curable sealant in an at least partially uncured state

Methodology Applied
Scientific EffectTemperature control: Cooling

Implementation Method 2

conditions to maintain the curable sealant in an at least partially uncured state

Methodology Applied
Scientific EffectOxygen exclusion:

Implementation Method 3

conditions to maintain the curable sealant in an at least partially uncured state

Methodology Applied
Scientific EffectMoisture exclusion:

Implementation Method 4

a sealant between the articles of different electrode potential can be used to help protect against galvanic corrosion by resisting penetration of water between the articles

Methodology Applied
Scientific EffectGalvanic corrosion resistance:

Implementation Method 5

compression of the sealant between the articles being sealed in order to provide a tight contiguous seal bond

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3203093B1Sealant articles and method of applying sealant
Publication Date: 2021.08.25 HAMILTON SUNDSTRAND CORP
  • EP3203093B1 patent drawingFigure 1~2
  • EP3203093B1 patent drawingFigure 3
  • EP3203093B1 patent drawingFigure 4

AI summary

A method of making an assembly is disclosed. According to the method, a curable sealant (12') is applied to a metal surface of a first article (10) , and the curable sealant (12') and first article (10) are stored under conditions to maintain the curable sealant (12') in an at least partially uncured state. The method further includes contacting the curable sealant (12') on the first article (10) metal surface with an electrically conductive surface of a second article (20,22), and curing the curable sealant (12').