Silane Coating Method for Metal Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for applying silane-based coatings on metal surfaces are limited in forming thick, stable layers without the use of organic solvents, which are environmentally and toxicologically undesirable, and struggle to provide effective corrosion protection without paint.
Innovation Solution
Applying unhydrolyzed silanes to metal surfaces followed by in-situ hydrolysis and curing, reducing the need for pre-hydrolysis and organic solvents, and allowing for the formation of thick, self-healing silane layers that provide both barrier and active corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If pre-hydrolyzed silane solutions are used to form thick coatings, then coating thickness is improved, but solution stability deteriorates due to condensation and sedimentation
Solution Approach 1:
The silane is pre-hydrolyzed and applied to the substrate surface before complete condensation occurs. The coating is then cured in place on the substrate, which stabilizes the reaction products and prevents sedimentation that would occur in concentrated aqueous solutions.
Solution Approach 2:
The substrate surface acts as an intermediary that stabilizes the hydrolyzed silane species. By anchoring the silane to the substrate through surface bonding, the system prevents the condensation and sedimentation that would otherwise occur in concentrated aqueous solutions.
2Stability of the object's composition
If organic solvents are added to stabilize silane solutions, then solution stability is improved, but environmental and toxicological concerns worsen due to VOC emissions
Solution Approach 1:
The harmful organic solvents are extracted from the system and replaced with water as the sole solvent. The stabilization mechanism shifts from organic solvent-based to substrate-based, eliminating VOC emissions while maintaining solution stability during application.
Solution Approach 2:
The solvent system is changed from organic-based to water-based. This parameter change eliminates VOC emissions while the application method (in-place curing on substrate) compensates for the reduced stability of concentrated aqueous silane solutions.
3Quantity of substance
If unhydrolyzed silanes are applied and cured in place, then organic solvent usage is reduced, but the ability to form thick stable layers deteriorates
Solution Approach 1:
The silane is applied in unhydrolyzed or partially hydrolyzed form and then cured in place on the substrate. This preliminary application followed by in-situ curing allows thick coatings to be formed without requiring stable concentrated aqueous solutions, as the curing process stabilizes the coating after deposition.
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 method achieves superior blank corrosion resistance comparable to chrome-based coatings, with enhanced self-healing properties and reduced VOC usage, suitable for various metals and applications including aerospace and electrically conductive assemblies.
Implementation Method 1
the silanes are pre-hydrolyzed by mixing them with water to an according treatment solution first. At that, the —C—O—Si— groups are partially hydrolyzed to —C—OH and HO—Si— (silanol) groups
Implementation Method 2
When subsequently bringing the treatment solution into contact with the metal surface, the silanol groups may condense with metal hydroxide (HO—M-) groups on the metal surface, forming —Si—O—M- groups, i.e. the cross-links
Implementation Method 3
The silanol groups of different silane molecules may also react with each other to siloxane (—Si—O—Si—) groups forming dimers, trimers, oligomers and/or polymers
Data Source
AI summary
Described herein is an improved method for applying silane-based coatings to solid surfaces, in particular metal surfaces. Also described herein are a silane-containing composition, a solid surface, in particular a metal surface, including a silane-based coating, and a method of using the silane-based coating in the transportation industry or in electrically conductive assembling.