Conversion Coating Composition for Corrosion-Resistant Metal Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chemical conversion coatings using chromium-free zinc phosphate face challenges in corrosion resistance and environmental impact due to high reactivity and sludge generation, necessitating improved coatings with enhanced adhesiveness and corrosion resistance.
Innovation Solution
A chemical conversion coating agent comprising zirconium, titanium, or hafnium, fluorine, and an allylamine-diallylamine copolymer, with specific content ratios and molecular weights, forms a film that enhances corrosion resistance and adhesiveness on metal surfaces, using a pH-controlled process and optional silane coupling agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical conversion coating using zinc phosphate is applied, then coating film adhesiveness is improved, but environmental burden increases and corrosion resistance is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the conversion coating agent by replacing zinc phosphate with a combination of zirconium/titanium/hafnium, fluorine, and allylamine-diallylamine copolymer. This parameter change eliminates phosphorus-containing waste and reduces environmental burden while improving corrosion resistance through the synergistic effect of the new component combination.
Solution Approach 2:
The patent creates a composite conversion coating system by combining multiple components (zirconium/titanium/hafnium, fluorine, and allylamine-diallylamine copolymer) that work synergistically. This composite approach provides both environmental benefits by eliminating zinc phosphate and performance benefits through enhanced corrosion resistance and coating adhesiveness.
2Reliability
If chromium-free zinc phosphate is used for chemical conversion coating, then environmental burden is reduced, but corrosion resistance after cationic electrodeposition or powder coating is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing zirconium/titanium/hafnium and fluorine in specific concentrations (zirconium: 10-10,000 ppm, fluorine: 10-12,500 ppm) combined with allylamine-diallylamine copolymer. These parameter changes create a conversion coating that provides sufficient corrosion resistance for subsequent cationic electrodeposition or powder coating applications.
Solution Approach 2:
The allylamine-diallylamine copolymer acts as an intermediary substance that facilitates the formation of a conversion coating with appropriate properties. It mediates between the metal substrate and the subsequent coating layers, providing both corrosion protection and good adhesiveness for cationic electrodeposition or powder coating.
3Reliability
If zirconium, titanium, or hafnium with fluorine and allylamine-diallylamine copolymer is used, then corrosion resistance is improved, but coating agent composition complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for each component (zirconium/titanium/hafnium: 10-10,000 ppm, fluorine: 10-12,500 ppm, copolymer: 25-5,000 ppm) to optimize corrosion resistance. While the composition is complex, the clearly defined parameters simplify formulation and manufacturing control, making the complexity manageable.
Solution Approach 2:
The patent employs a composite coating agent system where multiple components work synergistically. The complexity is justified by the superior corrosion resistance achieved, and the use of commercially available copolymers with defined molecular weights (500-500,000) helps manage the complexity through standardized materials.
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 provides improved corrosion resistance and adhesiveness, suitable for various coatings like cationic electrodeposition, powder, and solvent coatings, reducing environmental burden by minimizing phosphate use and sludge formation.
Implementation Method 1
chemical conversion coating has been previously applied to a metal substrate surface
Implementation Method 2
chemical conversion coating agents composed of at least one selected from a group consisting of zirconium, titanium, and hafnium, as well as fluorine
Implementation Method 3
an allylamine-diallylamine copolymer (C), in which the content of the metal component (A) is 10 to 10,000 ppm by mass in terms of elemental metal relative to the total mass of the chemical conversion coating agent
Data Source
AI summary
A chemical conversion coating agent that enables chemical conversion coating by which favorable corrosion resistance is obtained after coating. A chemical conversion coating agent which contains (A) at least one metal component that is selected from the group consisting of zirconium, titanium and hafnium, (B) fluorine and (C) an allylamine-diallylamine copolymer, wherein the content of the metal component (A) is 10 to 10,000 ppm by mass in terms of elemental metal relative to the total mass of the chemical conversion coating agent; the content ratio of a diallylamine segment derived from diallylamine in the allylamine-diallylamine copolymer (C) is 52% to 98% by mole relative to the total of an allylamine segment derived from allylamine and the diallylamine segment; the weight average molecular weight of the allylamine-diallylamine copolymer (C) is 500 to 500,000; and the content of the allylamine-diallylamine copolymer (C) is 25 to 5,000 ppm by mass in terms of the resin solid content concentration relative to the total mass of the chemical conversion coating agent.