Friction lining, method for its preparation and its use

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Solution Overview

Problem

The use of zinc and zinc alloys in friction linings for corrosion protection is environmentally harmful and leads to issues like foam formation, swelling, and complex production processes, necessitating a zinc-free alternative that provides sufficient corrosion protection.

Innovation Solution

Incorporating aluminum alloys with metals like magnesium (Mg) or titanium (Ti) into friction linings, which are less reactive than zinc alloys, forming a sacrificial anode to prevent rust and using these alloys in powder form to ensure uniform distribution and reduce adhesive corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If zinc or zinc alloys are used in friction linings for corrosion protection, then effective corrosion protection is achieved, but environmental harm and health risks increase due to heavy metal contamination

Engineering Contradiction:
Improvecorrosion protectionVSAvoidenvironmental harm
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter by replacing zinc-based corrosion protection agents with aluminum-based alternatives (such as Al, Al-Si, Al-Mg alloys), fundamentally altering the material system to eliminate heavy metal contamination while maintaining protective functionality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs aluminum powder as a sacrificial anode that is consumed during service, providing continuous corrosion protection through controlled oxidation of the aluminum rather than zinc, thereby eliminating environmental harm associated with zinc disposal

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If zinc alloys like AlZn5 are used in friction linings, then corrosion protection is provided, but foam formation and aluminum oxide flakes appear on the lining surface

Engineering Contradiction:
Improvecorrosion protectionVSAvoidfoam formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent modifies the alloy composition by using pure aluminum or aluminum alloys with specific element combinations (Al-Si, Al-Mg) instead of Al-Zn systems, changing the chemical reactivity parameters to prevent foam formation while maintaining corrosion protection

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the harmful zinc element from the alloy system, using aluminum-based materials alone or in combination with other non-harmful elements, thereby eliminating the source of foam formation and surface defects

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If zinc alloys are used in friction linings, then corrosion protection is achieved, but the friction lining swells depending on the alloy concentration

Engineering Contradiction:
Improvecorrosion protectionVSAvoiddimensional stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the compositional parameters by replacing zinc alloys with aluminum-based materials that have different thermal and mechanical expansion characteristics, thereby maintaining dimensional stability while providing corrosion protection

Inventive Principle:
Principle #35Parameter changes

4Object-affected harmful factors

If zinc-free alternatives are used in friction linings, then environmental harm is reduced, but sufficient corrosion protection must be maintained

Engineering Contradiction:
Improveenvironmental harmVSAvoidcorrosion protection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs aluminum powder as a self-sacrificing corrosion protection agent that automatically protects the friction lining through galvanic corrosion mechanisms, eliminating the need for external corrosion protection systems while maintaining environmental compatibility

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses composite material systems combining aluminum-based corrosion protection agents with friction lining materials, creating a multi-functional composite that provides both corrosion protection and friction characteristics without heavy metals

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 aluminum alloys offer effective corrosion protection, maintaining performance comparable to zinc-containing mixtures while avoiding environmental hazards, with the added benefit of reducing adhesive corrosion and allowing for continuous renewal as the friction lining wears.

Implementation Method 1

The aluminum alloys offer effective corrosion protection, maintaining performance comparable to zinc-containing mixtures

Methodology Applied
Scientific EffectGalvanic corrosion: Crevice Corrosion

Implementation Method 2

the use of an aluminium alloy which is less reactive than, for example, AlZn5 or another zinc alloy, but which still offers sufficient corrosion protection

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP3715666B1Friction lining, method for its preparation and its use
Publication Date: 2023.10.11 TMD FRICTION SERVICES GMBH

AI summary

AI alloys, especially Al-magnesium or aluminum-titanium alloys, are suitable as corrosion inhibitors in friction linings for brakes and clutches and serve as a replacement for zinc-metal or zinc compounds in such linings.