Low Temperature Corrosion Coating for Aircraft

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Solution Overview

Problem

Conventional corrosion inhibition coatings for aircraft components, especially those using hexavalent chromium compounds, pose environmental hazards and require high curing temperatures that interfere with cold working processes, lacking sufficient corrosion inhibition properties at lower temperatures.

Innovation Solution

A chromium-free corrosion inhibition coating comprising a silicate matrix with aluminum or aluminum alloys and inhibitors such as zinc molybdate, cerium citrate, and magnesium metasilicate, curable at low temperatures (20°C to 190°C), allowing compatibility with cold working processes and maintaining or exceeding the corrosion inhibition properties of hexavalent chromium-containing compounds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hexavalent chromium-containing coatings are used for corrosion protection, then corrosion inhibition properties are improved, but environmental hazards increase

Engineering Contradiction:

Improvecorrosion inhibition propertiesVSAvoidenvironmental hazards

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces hexavalent chromium compounds with alternative corrosion inhibitors (such as zinc molybdate, cerium compounds, or tungsten-based inhibitors) and modifies the coating composition to achieve effective corrosion protection without environmental hazards. This parameter change in chemical composition resolves the contradiction between corrosion performance and environmental safety.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If high curing temperatures (190°C or greater) are used for standard industry coatings, then coating performance is improved, but compatibility with cold working processes deteriorates

Engineering Contradiction:

Improvecoating performanceVSAvoidcompatibility with cold working processes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent develops low-temperature curing coatings that achieve full performance at curing temperatures below 190°C (preferably 50-150°C). This parameter change in curing temperature enables compatibility with cold working processes like shot peening, which require subsequent low-temperature operations, while maintaining adequate coating performance.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If chromium-free compounds are used to eliminate environmental hazards, then environmental safety is improved, but corrosion inhibition properties deteriorate

Engineering Contradiction:

Improveenvironmental safetyVSAvoidcorrosion inhibition properties

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs composite coating formulations combining multiple chromium-free corrosion inhibitors (such as zinc molybdate, cerium citrate, magnesium metasilicate, and metal phosphate silicates) with aluminum particles in a silicate matrix. This composite approach achieves corrosion inhibition properties equal to or better than hexavalent chromium-containing compounds while maintaining environmental safety.

Inventive Principle:

Principle #40Composite materials

4Adaptability or versatility

If low curing temperatures are used to enable cold working processes, then compatibility with cold working processes is improved, but corrosion inhibition properties deteriorate

Engineering Contradiction:

Improvecompatibility with cold working processesVSAvoidcorrosion inhibition properties

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses composite formulations with aluminum particles dispersed in a silicate matrix containing multiple corrosion inhibitors. This composite structure provides sufficient corrosion protection even at low curing temperatures (50-150°C), resolving the contradiction between low-temperature curing compatibility and corrosion inhibition effectiveness.

Inventive Principle:

Principle #40Composite 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 effective corrosion protection for aircraft components, extending their lifespan while being environmentally friendly and compatible with cold working processes, achieving equal or better corrosion inhibition than conventional hexavalent chromium-based coatings at lower curing temperatures.

Implementation Method 1

a corrosion inhibition coating, comprising: a base comprising a silicate matrix, wherein aluminum, an aluminum alloy, or a combination thereof, is present within the silicate matrix; and an inhibitor comprising: zinc molybdate, cerium citrate, magnesium metasilicate, a metal phosphate silicate, or a combination thereof

Methodology Applied

Scientific EffectCorrosion inhibition:

Implementation Method 2

wherein a curing temperature of the corrosion inhibition coating is about 20°C to about 190°C, preferably about 20°C to about 120°C

Methodology Applied

Scientific EffectCuring:

Data Source

PatentEP3722374B1Low temperature-cured corrosion inhibition coating

Publication Date: 2024.09.04 HAMILTON SUNDSTRAND CORP

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Figure 2

AI summary

Disclosed is a corrosion inhibition coating, comprising: a base comprising a silicate matrix, wherein aluminum, an aluminum alloy, or a combination thereof, is present within the silicate matrix; and an inhibitor comprising: zinc molybdate, cerium citrate, magnesium metasilicate, a metal phosphate silicate, or a combination thereof, wherein a curing temperature of the corrosion inhibition coating is about 20°C to about 190°C, preferably about 20°C to about 120°C. Also disclosed is a substrate coated with the corrosion inhibition coating, wherein the substrate is a peened part.