Composite Brake Body Coating for Wear and Corrosion Resistance

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Solution Overview

Problem

Brake bodies made of gray cast iron suffer from high weight, corrosion, and wear, leading to premature damage and increased particulate emissions, with existing coatings facing issues with adhesion and cracking under thermomechanical loads.

Innovation Solution

A brake body with a composite coating of an iron alloy matrix containing embedded tungsten carbide particles, applied using energy beams to achieve a strong metallurgical bond, with specific layer thicknesses and material compositions for enhanced wear resistance and corrosion protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gray cast iron is used for brake bodies, then high volumetric heat capacity and thermal shock resistance are achieved, but high weight, corrosion tendency, and wear increase

Engineering Contradiction:
Improvethermal shock resistanceVSAvoidbrake body weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The brake body uses a composite structure combining gray cast iron substrate with metallurgically bonded ceramic coatings (alumina, zirconia, or silicon carbide). This composite approach maintains the thermal properties of the cast iron while adding corrosion and wear resistance, and potentially reducing weight compared to solid ceramic alternatives.

Inventive Principle:
Principle #40Composite materials

2Reliability

If surface roughening by blasting is applied before thermal spraying, then coating adhesion is improved through mechanical clamping, but the process complexity increases

Engineering Contradiction:
Improvecoating adhesionVSAvoidsurface treatment process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the surface roughening step with the thermal heating step into a single integrated process sequence. The substrate is heated and simultaneously or subsequently coated, allowing the thermal energy to serve dual purposes: preparing the surface and enabling metallurgical bonding, thereby reducing overall process complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If complete substitution with ceramic materials is used, then corrosion resistance and wear protection are improved, but cost and manufacturing complexity increase

Engineering Contradiction:
Improvecorrosion and wear resistanceVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of making the entire brake body from expensive ceramic materials, the patent applies ceramic coatings only to the friction surfaces where wear and corrosion protection is most needed. This local application of quality maintains performance while significantly reducing material costs and manufacturing complexity compared to full ceramic substitution.

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 provides a cost-effective brake body with improved wear resistance, reduced corrosion, and lower particulate emissions, while maintaining good friction values and preventing cracking, thus extending the lifespan of the brake body.

Implementation Method 1

at least one energy beam is directed onto a surface of a planar base body of the brake body in order to melt the coating material and in this way to coat the surface side of the flat base body with a first build-up layer

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

a significantly stronger bond is possible through metallurgical bonding, which requires the use of thermal energy to enable the atomic diffusion process at the interface between the substrate and the coating

Methodology Applied
Scientific EffectAtomic diffusion: Diffusion

Data Source

PatentEP4459150A1Brake body for a motor vehicle and method for producing a brake body
Publication Date: 2024.11.06 VOLKSWAGEN AG
  • EP4459150A1 patent drawingFigure 1
  • EP4459150A1 patent drawingFigure 2
  • EP4459150A1 patent drawingFigure 3

AI summary

The invention relates to a brake body (1) for a motor vehicle, comprising a base body (G) that is at least partially planar, on whose surface faces (Fa) at least two superstructure layers (B1, B2) are applied, at least partially. The superstructure layers (B1, B2) form a surface which, when the brake body (1) is mounted on the motor vehicle, serves as a friction surface (12) for a brake pad. A bonding zone (A) exists in which both a material of the base body (G) and a material of a superstructure layer (B1) adjacent to it are present. The second superstructure layer (B2) consists of a composite of an iron alloy matrix (E) with embedded tungsten carbide particles (W). According to the invention, the volume of the embedded tungsten carbide particles (W) relative to the volume of the iron alloy matrix (E) is in the range of 1% to 19%. Furthermore, a method for manufacturing a brake body is proposed.