Black Coating Film on Zinc Plated Components
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Solution Overview
Problem
Black chromate treatments using trivalent chromium struggle to achieve both high corrosion resistance and a dark black appearance on zinc plated components, often requiring multiple top coating processes and increasing costs due to limitations in black pigment content.
Innovation Solution
A method involving a zinc plated substrate treated with a trivalent black chromate solution followed by a single application of a coating film-forming resin containing a high amount of black pigment and an alkoxysilane oligomer, which is then heat-cured to achieve both corrosion resistance and a dark black appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the amount of black pigment in the coating film-forming resin is increased to achieve dark black appearance, then the blackness degree is improved, but the corrosion resistance deteriorates
Solution Approach 1:
An alkoxysilane oligomer is introduced as an intermediary substance between the black pigment and the corrosion protection system. The oligomer forms a protective network that allows high pigment content (25-65% by weight) to achieve dark black appearance (L value 28 or less) while maintaining corrosion resistance through the silane-based protective matrix
Solution Approach 2:
The coating composition creates a composite material system combining black pigment, alkoxysilane oligomer, and other coating components. This composite structure enables the coating to simultaneously achieve dark black color and high corrosion resistance, resolving the contradiction between appearance and protection
2Illumination intensity
If multiple top coating processes are performed to achieve dark black appearance, then the blackness degree is improved, but the process complexity and cost increase
Solution Approach 1:
The invention merges the coloration function and corrosion protection function into a single coating composition. By incorporating alkoxysilane oligomer and high amounts of black pigment, the coating achieves both dark black appearance and corrosion resistance in one application, eliminating the need for multiple coating processes
3Illumination intensity
If the amount of sulfur in the chemical conversion film is increased to achieve dark black appearance, then the blackness degree is improved, but the corrosion resistance deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the coating film by incorporating alkoxysilane oligomer. This parameter change allows the system to achieve dark black appearance through pigment concentration rather than sulfur content, thereby maintaining corrosion resistance while improving blackness degree
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 allows for a simple process to achieve a black coating film with high corrosion resistance and a dark black appearance in a single operation, enhancing economic efficiency and simplifying the manufacturing process.
Implementation Method 1
an alkoxysilane oligomer
Implementation Method 2
an alkoxysilane oligomer
Implementation Method 3
a black pigment in an amount of from 25 to 65% by weight
Implementation Method 4
heat-curing the black coating composition thus coated
Data Source
AI summary
An object is to provide a technique capable of forming a film having a dark black appearance and high corrosion resistance on a zinc plated component in a simple process, and a black coating film-forming vehicle component and/or fastening component that is obtained by: treating a surface of a zinc plated metal substrate with a black chemical conversion treatment agent containing trivalent chromium as an active ingredient, to form a black chemical conversion treatment film having an L value (brightness) of from 33 to 30; coating a black coating composition containing a black pigment in an amount of from 25 to 65% by weight in a thermosetting film-forming component and an alkoxysilane oligomer, on the black chemical conversion treatment film; and heat-curing the black coating composition thus coated.