Solvent-Free SiC Slurry for Ceramic Brake Friction Layers

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Solution Overview

Problem

Existing methods for producing and repairing friction layers on ceramic supporting bodies, such as brake discs, are complex, costly, and require solvents, binders, and multiple processing steps.

Innovation Solution

A procedure involving a solvent-free slicker based on water, containing silicon carbide (SIC) and carbon particles, is applied to the ceramic surface, followed by drying and high-temperature treatment with liquid silicon to form a carbon-free SISIC friction layer with at least 70% volume SIC content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional methods using solvents, binders, and preceramic polymers are used to produce friction layers, then the friction layer can be formed on the supporting body, but the process becomes complex, costly, and time-consuming with multiple processing steps

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidprocessing steps complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts and removes unnecessary components from the conventional slurry composition, specifically eliminating solvents, binders, and preceramic polymers. The simplified slurry contains only silicon carbide particles, carbon particles, and water, reducing the formulation to essential components only while maintaining effective friction layer formation

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention enables continuous production by eliminating intermediate steps such as binder crosslinking and pyrolysis. The slurry can be applied and directly fired to form the friction layer in a continuous process flow, improving manufacturing efficiency and reducing process complexity

Inventive Principle:
Principle #20Continuity of useful action

2Productivity

If multiple processing steps including binder crosslinking and pyrolysis are used, then the friction layer achieves proper structure, but the production time and cost increase significantly

Engineering Contradiction:
Improveproduction speedVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The invention extracts and eliminates time-consuming processing steps, specifically removing the binder crosslinking and pyrolysis stages from the manufacturing process. The simplified process applies slurry directly to the supporting body and proceeds to firing, reducing total processing time while maintaining product quality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention skips intermediate processing steps that are traditionally required, such as binder crosslinking and pyrolysis. By using a slurry formulation without organic binders, the process jumps directly from slurry application to firing, significantly accelerating production

Inventive Principle:
Principle #21Skipping (Rushing through)

3Ease of manufacture

If solvents and binders are used in the slurry formulation, then the slurry has proper flow and adhesion properties, but the process requires additional crosslinking and pyrolysis steps

Engineering Contradiction:
Improveslurry application simplicityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention extracts and removes solvents and binders from the slurry formulation, replacing them with a simplified composition of silicon carbide particles, carbon particles, and water. This elimination of organic components removes the need for crosslinking and pyrolysis steps, improving manufacturing efficiency

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the fundamental parameters of the slurry formulation by eliminating organic binders and solvents. The slurry relies on the physical properties of inorganic particles and water for application, fundamentally altering the formulation approach while simplifying the overall manufacturing process

Inventive Principle:
Principle #35Parameter changes

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

This method enables simple, quick, and cost-effective restoration of worn or defective friction layers, achieving high wear resistance and excellent thermal conductivity, thus extending the lifespan of ceramic components.

Implementation Method 1

followed by drying and high-temperature treatment

Methodology Applied
Scientific EffectDrying: Evaporation

Implementation Method 2

high-temperature treatment with liquid silicon to form a carbon-free SISIC friction layer

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

achieving high wear resistance and excellent thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4368852B1Method for manufacturing friction units
Publication Date: 2025.04.16 REBRAKE CERAMIC BRAKE SERVICE GMBH
  • EP4368852B1 patent drawingFigure 1~2C

AI summary

A method for producing friction units by coating a support body with a C/SiC material, wherein the support body is first cleaned on its surface to be coated, then a water-based slurry containing particles of SiC and carbon is applied to the support body, the coated support body is subjected to drying in order to remove the water from the slurry and create an open porosity, and subsequently the support body with the dried, open-porous and crack-free coating is subjected to a high-temperature treatment with the introduction of liquid silicon into the open porosity until a carbon-free friction layer consisting exclusively of SiC and silicon is formed, wherein the composition of the slurry is selected such that the SiC content in the friction layer is at least 70 vol.%.