Corrosion-Resistant Sol-Gel Coating for Adhesion Without Blistering
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Solution Overview
Problem
Existing sol-gel films used on aircraft surfaces suffer from porosity issues that lead to water retention, osmotic pressure buildup, and corrosion, while traditional corrosion inhibitors reduce adhesive properties and cause blistering.
Innovation Solution
A coating system comprising a salt of a corrosion inhibitor with thiol moieties, an organosilane, an acid, and a metal alkoxide is formed, solubilizing the corrosion inhibitor to prevent porosity and blistering, and ensuring adhesion and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primer is coated on the metal surface to prevent corrosion, then corrosion resistance is improved, but adhesion to the metal surface deteriorates
Solution Approach 1:
The patent introduces a sol-gel adhesive coating as an intermediary layer between the metal surface and the primer. This intermediate sol-gel layer provides both adhesion to the metal surface and a suitable interface for primer coating, resolving the contradiction between corrosion resistance and adhesion by mediating the interface between metal and primer
Solution Approach 2:
The patent creates a composite coating system consisting of multiple layers: metal surface, sol-gel adhesive layer, and primer layer. This composite structure combines the advantages of each material - the metal provides substrate strength, the sol-gel provides adhesion and corrosion resistance, and the primer provides additional corrosion protection
2Strength
If a sol-gel film is applied to the metal surface, then adhesion is improved, but porosity increases leading to water retention and corrosion
Solution Approach 1:
The patent modifies the sol-gel film parameters by incorporating specific inorganic components (such as zirconium, zinc, or calcium compounds) and controlling the sol-gel process conditions to reduce porosity. This parameter change allows the sol-gel film to maintain its adhesive properties while reducing water retention and improving corrosion resistance
3Reliability
If corrosion inhibitors are added to sol-gel films, then corrosion resistance is improved, but adhesive properties decrease and blistering occurs
Solution Approach 1:
The patent changes the chemical parameters of the corrosion inhibitors by selecting specific compounds (such as zirconium, zinc, or calcium-based inhibitors) and controlling their concentration and distribution within the sol-gel matrix. This parameter optimization allows corrosion protection without compromising adhesion or causing blistering
Solution Approach 2:
The patent utilizes the controlled porous structure of the sol-gel film to accommodate corrosion inhibitors within the pore network. The inhibitors are incorporated during the sol-gel processing, allowing them to be distributed throughout the film without creating surface defects or reducing adhesion
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 coating system effectively prevents corrosion and blistering, maintaining adhesive properties by solubilizing the corrosion inhibitor, forming a stable sol-gel film with improved durability and adhesion.
Implementation Method 1
a corrosion inhibitor having one or more thiol moieties
Implementation Method 2
adhesive sol-gel films
Implementation Method 3
an organosilane, an acid, and a metal alkoxide
Implementation Method 4
reaction product of a salt of a corrosion inhibitor
Data Source
AI summary
Aspects described herein generally relate to a method of coating a metallic surface. The method includes forming a solution including a corrosion inhibitor having one or more thiol moieties and a hydroxide. The metallic surface is coated with the solution to form a treated metallic surface. The treated metallic surface is further coated with an organosilane, an acid, and a metal alkoxide to form a coating system.