Inorganic Passivation Material via Phosphate Ester Modification
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Solution Overview
Problem
Conventional organic-inorganic hybrid resins used for surface passivation of galvanized steel and aluminum alloys lack sufficient weather resistance and heat resistance, and the use of hexavalent chromium is restricted due to environmental concerns, necessitating an alternative that provides both corrosion and heat resistance while being environmentally friendly.
Innovation Solution
A method involving a sol-gel reaction between tetraalkoxysilane, trialkoxysilane, and a catalyst under acidic conditions to form an inorganic resin material, which is then modified with phosphate ester to create an inorganic passivation material with a high inorganic content, resulting in an inorganic passivation protective film with improved hardness, corrosion resistance, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic-inorganic hybrid resins are used for surface passivation, then film-forming ability is maintained, but weather resistance and heat resistance are insufficient
Solution Approach 1:
The patent uses a composite material system consisting of inorganic resin (formed from tetraalkoxysilane and trialkoxysilane) as the primary matrix combined with phosphate ester modifiers. This composite structure provides both film-forming ability and superior heat resistance, overcoming the limitations of conventional organic-inorganic hybrid resins that relied heavily on organic components.
Solution Approach 2:
The patent changes the chemical composition parameters by using specific ratios of tetraalkoxysilane (5-80 parts) to trialkoxysilane (10-80 parts) and controlling the phosphate ester content (0.1-10 parts per 100 parts inorganic resin). These parameter optimizations enable the material to achieve both good film-forming properties and enhanced heat resistance up to 500°C.
2Reliability
If hexavalent chromium is used for surface passivation, then corrosion resistance is achieved, but environmental compliance deteriorates
Solution Approach 1:
The patent extracts and eliminates hexavalent chromium from the passivation system entirely, replacing it with an inorganic resin-based system modified by phosphate ester. This removal of harmful Cr6+ ions achieves compliance with RoHS and WEEE directives while maintaining effective corrosion resistance through the inorganic phosphate ester modified resin coating.
3Object-affected harmful factors
If inorganic resin material is used without phosphate ester modification, then environmental friendliness is improved, but surface hardness and corrosion resistance are insufficient
Solution Approach 1:
The phosphate ester acts as an intermediary modifier that enhances the properties of the inorganic resin. It serves as a bridging component that improves surface hardness and corrosion resistance of the environmentally friendly inorganic resin system without requiring harmful Cr6+ ions. The phosphate ester modification creates a more durable and functional coating while maintaining environmental compliance.
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 inorganic passivation material achieves enhanced corrosion resistance, heat resistance, and surface hardness, exceeding 400 hours of salt spray resistance and maintaining integrity at 500°C for 1 minute, while being free of heavy metal ions like Cr6+, thus meeting environmental and performance requirements.
Implementation Method 1
mixing about 5 to 80 parts by weight of tetraalkoxysilane, about 10 to 80 parts by weight of trialkoxysilane, and about 1 to 30 parts by weight of catalyst to perform a reaction at pH of 0.05 to 4 to form an inorganic resin material
Implementation Method 2
The inorganic resin material is modified by phosphate ester to form an inorganic passivation material
Implementation Method 3
an inorganic passivation protective film formed by coating and curing the inorganic passivation material
Data Source
AI summary
A method for forming an inorganic passivation material is provided. The method includes mixing about 5 to 80 parts by weight of trialkoxysilane, about 10 to 80 parts by weight of tetraalkoxysilane, and about 1 to 30 parts by weight of catalyst to perform a reaction at pH of about 0.05 to 4 to form an inorganic resin material. The inorganic resin material is modified by phosphate ester to form an inorganic passivation material, wherein phosphate ester is about 0.1-10 parts by weight based on 100 parts by weight of the inorganic resin material. An inorganic passivation material and a passivation protective film produced therefrom are also provided.