Graphene Anti-Corrosion Coating via Electrophoretic Deposition

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Solution Overview

Problem

Structural materials in maritime environments, such as copper-beryllium and corrosion-resistant stainless steel, face significant corrosion due to high salt concentrations and electrical conductivity, leading to substantial economic losses in industries like shipping, with existing coatings failing to effectively control cathodic current density without compromising mechanical properties.

Innovation Solution

A corrosion-resistant surface treatment using electrophoretic deposition of uniformly overlapping micron-sized graphene flakes, which reduces cathodic current density and provides mechanical stability, scratch resistance, and self-cleaning properties, achieved through a process involving electrochemical exfoliation and rotation in an electrophoretic deposition cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coatings are applied to reduce corrosion, then corrosion resistance is improved, but mechanical properties are compromised

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmechanical properties

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies a thin film coating of exfoliated graphite flakes (0.5-5 micrometers thick) that forms a flexible, adherent layer on the metal substrate. This thin film structure provides corrosion protection while minimizing impact on the underlying metal's mechanical properties, resolving the contradiction between corrosion resistance and mechanical strength

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite material system combining metal substrate with exfoliated graphite flakes suspended in binder resin. This composite structure leverages the corrosion-resistant properties of graphite while maintaining the mechanical strength of the metal base, achieving both improved corrosion resistance and preserved mechanical properties

Inventive Principle:

Principle #40Composite materials

2Reliability

If thick coating layers are applied to enhance corrosion protection, then corrosion resistance is improved, but mechanical stability deteriorates

Engineering Contradiction:

Improvecorrosion protectionVSAvoidmechanical stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent specifies a controlled coating thickness of 0.5-5 micrometers, forming a thin film that provides adequate corrosion protection without creating a thick, brittle layer that would compromise mechanical stability. The thin film structure maintains flexibility and adhesion to the substrate

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent optimizes the coating thickness parameter within a specific range (0.5-5 micrometers) to achieve the optimal balance between corrosion protection and mechanical stability. This parameter control ensures the coating is thick enough to protect against corrosion but thin enough to maintain the substrate's mechanical properties

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If electrophoretic deposition is used to apply graphene coating, then uniform monolayer coverage is achieved, but process complexity increases

Engineering Contradiction:

Improveuniform coating coverageVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical coating application methods with electrophoretic deposition, which uses electrical fields to automatically suspend and deposit graphite flakes uniformly across the substrate surface. This electrical field-based approach achieves monolayer coverage more simply than mechanical means would require

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrophoretic deposition process allows the coating material (graphite flakes in binder resin) to self-organize and self-deposit uniformly on the substrate when an electrical field is applied. The system self-regulates the deposition process to achieve consistent monolayer coverage without requiring complex external control mechanisms

Inventive Principle:

Principle #25Self-service

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 graphene-reinforced composite coating significantly reduces corrosion rates by an order of magnitude compared to bare copper, as confirmed by Tafel analysis, while maintaining mechanical stability and offering enhanced resistance to electrochemical degradation.

Implementation Method 1

electrophoretic deposition of uniformly overlapping micron-sized graphene flakes

Methodology Applied

Scientific EffectElectrophoresis: Electrophoresis

Implementation Method 2

electrochemical exfoliation using at least one graphite rod immersed in a mixture of water and a suitable ionic liquid

Methodology Applied

Scientific EffectElectrochemical exfoliation: Electrolysis

Data Source

PatentUS9920447B2Graphene anti-corrosion coating and method of application thereof

Publication Date: 2018.03.20 LUMINIT INC

AI summary

A graphene composite coating on a metal surface with excellent corrosion resistance by electrophoretic or electrolytic deposition has been obtained. The composite coating was shown to significantly increase the resistance of the metal surface to electrochemical degradation.The graphene coating significantly reduces cathodic current, which is an indicator of the rate of corrosion at the interface between the cathodic material and the anodic material.