Corrosion-Protective Bushing Structure for Delamination Resistance

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Solution Overview

Problem

Existing maintenance-free bushings face challenges with corrosion resistance and delamination when exposed to environmental conditions, particularly when the load-bearing substrate is made of iron alloys, which affects their longevity and load capability.

Innovation Solution

A sliding article comprising a load-bearing substrate coated with a metal-containing corrosion protective layer, made of magnesium, aluminum, titanium, scandium, or zinc, and a sliding layer applied over the substrate, with specific thickness ratios and surface structures to enhance corrosion resistance and maintain high load-bearing capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a load bearing substrate made of iron alloys is used, then high load capability is achieved, but corrosion resistance deteriorates when exposed to environmental conditions

Engineering Contradiction:
Improveload capabilityVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The invention uses a composite structure consisting of a load-bearing substrate (iron alloy) combined with a corrosion-protective metal-containing layer. This composite material approach allows the substrate to provide high load capability while the overlaying metal-containing layer provides corrosion resistance, thus resolving the contradiction between strength and corrosion resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The metal-containing layer acts as an intermediary between the iron alloy substrate and the corrosive environment. It serves as a protective barrier that prevents direct contact between the substrate and environmental factors causing corrosion, while still allowing the substrate to fulfill its load-bearing function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If adhesive laminating is used to connect substrate and sliding layer, then maintenance free operation is achieved, but delamination resistance deteriorates under environmental exposure

Engineering Contradiction:
Improvemaintenance free operationVSAvoiddelamination resistance
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The invention changes the material parameters by introducing a metal-containing layer with specific thickness (at least 25 μm) and composition between the substrate and sliding layer. This parameter change enhances the overall stability and delamination resistance of the composite structure under environmental exposure while maintaining maintenance-free operation.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If corrosion protective coating is applied, then corrosion resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention applies a metal-containing layer with specific local properties (thickness of at least 25 μm, containing specific metals) only where corrosion protection is needed on the load-bearing substrate. This localized approach provides effective corrosion protection while avoiding unnecessary complexity in other areas of the component.

Inventive Principle:
Principle #3Local quality

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 solution significantly increases the corrosion resistance and maintenance-free lifetime of bushings, achieving a Corrosion Resistance Rating of at least 1000 hours and maintaining high tensile strength, while allowing for high load-bearing capacity and sizing capability.

Implementation Method 1

The metal containing layer is a corrosion protective layer and contains a metal selected from magnesium, aluminium, titanium, scandium, zinc, or any combination thereof

Methodology Applied
Scientific EffectGalvanic protection:

Data Source

PatentEP3779219B1Corrosion resistant bushing
Publication Date: 2023.06.07 SAINT GOBAIN PERFORMANCE PLASTICS PAMPUS GMBH
  • EP3779219B1 patent drawingFigure 1A~1D
  • EP3779219B1 patent drawingFigure 2A~2B
  • EP3779219B1 patent drawingFigure 3A~3B

AI summary

A sliding article comprising: a load bearing substrate, having a first major surface, a second major surface, and an edge, the load bearing having a thickness t1, an metal containing layer overlying and in direct contact with the first major surface, the metal containing layer having a thickness t2, wherein t2 is at least 10 microns, a sliding layer overlying the first or the second major surface, wherein a ratio of t2/tl is at least 1/10.