Thiol Sol-Gel Coating for Corrosion Resistance Without Blistering
Find Innovative SolutionsGenerate Solutions
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 is formed using a corrosion inhibitor salt with thiol moieties, an organosilane, an acid, and a metal alkoxide, solubilizing the inhibitor to prevent porosity and blistering, and maintaining adhesive properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional corrosion inhibitors are dispersed within the sol-gel network, then corrosion resistance is improved, but adhesive ability and anticorrosion ability decrease due to insoluble entrained particles causing osmotic blistering
Solution Approach 1:
The patent changes the chemical state of the corrosion inhibitor from insoluble dispersed particles to soluble salt form. By using soluble salts of corrosion inhibitors (such as zinc chloride, calcium chloride, or sodium chloride) instead of traditional insoluble inhibitors, the system eliminates osmotic blistering while maintaining corrosion resistance. The soluble salts remain dissolved in the sol-gel matrix, preventing the formation of insoluble entrained particles that cause blistering.
Solution Approach 2:
The patent creates a composite sol-gel coating system that integrates multiple components: soluble corrosion inhibitor salts, organosilane precursors, and other sol-gel forming agents. This composite approach allows the corrosion protection function to be achieved through soluble ionic species rather than insoluble particles, resolving the contradiction between corrosion resistance and blistering prevention.
2Strength
If sol-gel films are applied to metal surfaces, then adhesion between metal and primer is improved, but pores form within the film over time retaining water and promoting corrosion
Solution Approach 1:
The patent modifies the chemical composition of the sol-gel film by incorporating soluble corrosion inhibitor salts that remain dissolved in the matrix. This chemical modification allows the film to maintain its adhesive properties while simultaneously providing corrosion resistance through the soluble ionic species, eliminating the need for porous structures that would retain water.
3Reliability
If hexavalent chromium is used in primers for corrosion protection, then corrosion resistance is improved, but regulatory compliance deteriorates due to pressure to eliminate hexavalent chromium
Solution Approach 1:
The patent substitutes hexavalent chromium-based corrosion protection with a completely different chemical mechanism using soluble corrosion inhibitor salts (such as zinc chloride, calcium chloride, or sodium chloride) incorporated into the sol-gel coating. This parameter change in the chemical composition eliminates the need for regulated hexavalent chromium while maintaining effective corrosion protection through the soluble salt system.
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 system provides corrosion resistance and adhesion without blistering, ensuring effective protection and adherence to metal surfaces.
Implementation Method 1
a corrosion inhibitor having one or more thiol moieties
Implementation Method 2
an organosilane, an acid, and a metal alkoxide to form a coating system
Implementation Method 3
forming a solution comprising a corrosion inhibitor having one or more thiol moieties and a hydroxide
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.