Conversion Coating Dye for UV Inspection

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Solution Overview

Problem

Trivalent chromium or chromium-free conversion coatings are colorless and difficult to visually inspect for flaws, as they are not visible under electromagnetic radiation within the human visual spectrum, making it challenging to assess their integrity without additional additives.

Innovation Solution

Incorporating a dye compound that interacts with electromagnetic radiation outside the human visual spectrum, such as ultraviolet or infrared radiation, to produce observable emissions, allowing for inspection of the coating integrity using appropriate instrumentation or the naked eye without altering the coating's appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If trivalent chromium or chromium-free conversion coatings are used to replace hexavalent chromium conversion coatings, then corrosion protection and environmental safety are improved, but visual inspection capability deteriorates because the coatings become colorless and invisible under electromagnetic radiation within the human visual spectrum

Engineering Contradiction:

Improvecorrosion protectionVSAvoidvisual inspection capability

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies the color changes principle by incorporating dye compounds into the conversion coating formulation. These dye compounds absorb electromagnetic radiation within the human visual spectrum and re-emit it at different wavelengths, causing the colorless conversion coating to exhibit visible coloration. This allows inspectors to visually assess coating uniformity, coverage, and defects while maintaining the underlying corrosion protection functionality of the trivalent chromium or chromium-free conversion coating.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent employs the intermediary principle by introducing dye compounds as mediator substances between the invisible conversion coating and the human visual inspection system. The dye compound serves as an intermediary that converts the invisible coating into a visually detectable form without altering the fundamental corrosion protection mechanism. The dye absorbs visible light and transforms it into observable coloration, enabling quality control while the conversion coating maintains its corrosion inhibiting properties.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If hexavalent chromium conversion coatings are used, then visual inspection is easy due to yellow coloration, but environmental safety and health hazards worsen due to toxicity and regulatory phase-out

Engineering Contradiction:

Improvevisual inspection easeVSAvoidtoxicity and environmental hazard

Core Design Contradiction:

Difficulty of detecting and measuringVSObject-affected harmful factors

Solution Approach 1:

The patent applies color changes by adding dye compounds to the trivalent chromium or chromium-free conversion coating. This enables the coating to display visible coloration similar to hexavalent chromium coatings, restoring visual inspection capability. The dye compounds absorb and re-emit light in the visible spectrum, providing yellow or other colored appearance that facilitates quality control while eliminating the use of toxic hexavalent chromium.

Inventive Principle:

Principle #32Color changes

Solution Approach 2:

The patent converts the harm of colorless coatings (invisibility) into a benefit by introducing dye compounds that provide visible coloration. The very property that made trivalent chromium coatings problematic for inspection (being colorless) is transformed into an advantage through the addition of dyes that enhance visibility without compromising corrosion protection. This allows the industry to benefit from both the environmental safety of non-hexavalent coatings and the inspection ease previously provided only by hexavalent coatings.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Enables effective visualization of the coating's uniformity and detection of defects, ensuring quality control and maintenance of corrosion protection properties without altering the coating's properties or appearance.

Implementation Method 1

a dye compound that interacts with electromagnetic radiation outside the human visual spectrum to produce an observable emission

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS11807779B2Additive for quality determination of conversion coatings

Publication Date: 2023.11.07 HAMILTON SUNDSTRAND CORP

AI summary

A method of applying a trivalent chromium or chromium-free conversion coating to a metallic substrate including mixing a dye compound that interacts with electromagnetic radiation outside the human visual spectrum but not electromagnetic radiation that is within the human visual spectrum to produce an observable emission into the trivalent chromium or chromium-free conversion coating mixture to allow for inspection of the coating after applied with a correlating electromagnetic radiation source.