Coated Fastener With Split Coatings for Conduction and Corrosion Control
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Solution Overview
Problem
Aerospace fasteners with conductive cores coated with dielectric materials experience insufficient conduction and high heat generation due to high current density when there is an inadequate connection between the fastener and the material it secures, leading to potential galvanic corrosion and friction issues.
Innovation Solution
A coated fastener design featuring a conductive core with a dielectric coating on a threaded portion and a conductive friction modifier material, such as graphite, on a non-threaded portion, which provides improved lubricity and electromagnetic protection, reducing current density and heat generation by applying the conductive friction modifier material using a specific coating method and apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the fastener is coated with dielectric material to prevent galvanic corrosion, then corrosion protection is improved, but electromagnetic conduction deteriorates due to insufficient conduction through the core material
Solution Approach 1:
The patent applies different coating materials to different portions of the fastener core body. The first portion (threaded portion) receives a dielectric coating for corrosion protection, while the second portion (non-threaded portion) receives a conductive friction modifier coating to maintain electromagnetic conduction. This local differentiation resolves the contradiction by providing both corrosion protection and conduction where needed.
Solution Approach 2:
The patent uses composite coating structures where different material properties are combined on different portions of the same component. The dielectric coating provides corrosion resistance while the conductive friction modifier coating provides electromagnetic conduction, creating a composite solution that addresses both requirements simultaneously.
2Reliability
If the fastener connection is insufficient leading to high current density, then electromagnetic conduction is maintained, but heat generation increases causing potential damage
Solution Approach 1:
The conductive friction modifier coating is applied specifically to the non-threaded portion of the fastener where heat generation from high current density is most problematic. This localized application reduces heat generation in the critical area while maintaining conduction properties where needed.
Solution Approach 2:
The patent converts the harmful effect of high current density and associated heat generation into a beneficial outcome by applying the conductive friction modifier coating. This coating improves electromagnetic conduction and reduces friction, thereby reducing heat generation and transforming the potential harm into improved performance.
3Ease of operation
If a coating is applied to the entire fastener to improve lubricity, then friction is reduced, but electromagnetic conduction deteriorates due to dielectric material blocking conduction
Solution Approach 1:
The conductive friction modifier coating is applied only to the non-threaded portion of the fastener where lubricity is needed, while the threaded portion receives a dielectric coating. This localized application provides lubricity where required while maintaining electromagnetic conduction in the threaded portion.
Solution Approach 2:
The patent uses composite coating materials with different properties applied to different portions of the fastener. The conductive friction modifier provides both lubricity and conduction, while the dielectric coating provides corrosion protection, creating a composite solution that balances lubricity and conduction requirements.
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 solution enhances the fastener's transition fit, lubricity, and electromagnetic protection, reducing heat generation and preventing galvanic corrosion, while ensuring reliable conduction and assembly efficiency.
Implementation Method 1
a second coating comprising a conductive friction modifier material and disposed on the second portion of the core body to provide the fastener with a desired transition hold fit, improved lubricity
Implementation Method 2
a second coating comprising a conductive friction modifier material and disposed on the second portion of the core body to provide the fastener with a desired transition hold fit, improved lubricity, and improved electromagnetic effects protection
Data Source
AI summary
A coated fastener includes a core body comprising conductive material and including a first portion and a second portion. The coated fastener also includes a first coating comprising dielectric material and disposed on the first portion of the core body. The coated fastener further includes a second coating comprising a conductive friction modifier material and disposed on the second portion of the core body to provide the fastener with a desired transition hold fit, improved lubricity, and improved electromagnetic effects protection.