Brake Disk Coating Stack for Wear Resistance Without Cracking
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Solution Overview
Problem
Friction brakes in motor vehicles experience wear and corrosion due to the frictional contact between the brake pad and brake disk, leading to the generation of brake dust, and existing antiwear layers and intermediate layers do not adequately address adhesion, cracking resistance, and corrosion issues.
Innovation Solution
A metallic intermediate layer, preferably a nickel-, cobalt-, or iron-based alloy with a two-phase microstructure, is applied by laser buildup welding to the main element, providing improved adhesion and cracking resistance, and an antiwear layer is applied on top using thermal spraying or laser buildup welding, incorporating ceramic coatings or iron-based alloys with embedded hard material particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an antiwear layer is applied to the brake disk, then wear resistance is improved, but adhesion between layers and resistance to cracking deteriorate
Solution Approach 1:
The patent applies a composite layer system consisting of an antiwear layer (ceramic or metal matrix with hard particles) on top of a metallic intermediate layer (nickel-, cobalt-, or iron-based alloy) on the gray cast iron main element. This composite structure combines the wear resistance of hard materials with the ductility and adhesion of metallic materials, resolving the contradiction between wear resistance and cracking resistance.
Solution Approach 2:
The metallic intermediate layer serves as an intermediary between the brittle antiwear layer and the gray cast iron main element. It provides a transition zone that improves adhesion, reduces thermal stress, and prevents cracking from propagating into the main element, thereby maintaining reliability while enabling the use of hard antiwear coatings.
2Ease of manufacture
If conventional application methods are used for antiwear layers, then manufacturing simplicity is maintained, but layer adhesion and bonding strength deteriorate
Solution Approach 1:
The patent replaces conventional mechanical application methods (such as manual coating or simple spraying) with laser buildup welding for applying the metallic intermediate layer. This thermal processing method ensures strong metallurgical bonding and controlled microstructure, significantly improving layer adhesion while maintaining manufacturing efficiency through automation.
Solution Approach 2:
The patent controls the microstructure of the metallic intermediate layer by adjusting laser processing parameters (power, speed, pulse duration) to achieve a two-phase microstructure with specific phases making up at least 5% by volume each. This parameter optimization ensures both strong adhesion and desired mechanical properties without compromising ease of manufacture.
3Device complexity
If the intermediate layer is made with simple microstructure, then manufacturing complexity is reduced, but fracture toughness and cracking resistance deteriorate
Solution Approach 1:
The patent achieves a two-phase microstructure in the metallic intermediate layer by controlling laser processing parameters, ensuring that each phase constitutes at least 5% by volume. This controlled microstructural complexity significantly improves fracture toughness and cracking resistance compared to simple single-phase structures, while remaining manufacturable through standardized laser processes.
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 enhances the adhesion and corrosion resistance of the friction brake element, inhibits crack propagation, and provides effective protection against wear and corrosion, resulting in a more durable and long-lasting brake system.
Implementation Method 1
the metallic intermediate layer is applied by laser buildup welding to the main element
Implementation Method 2
the antiwear layer is applied by thermal spraying or laser buildup welding to the intermediate layer
Data Source
AI summary
The disclosure relates to a frictional brake element for a friction brake of a motor vehicle, in particular brake disk, having a main element which is manufactured in particular from grey cast iron and which has at least one wear protection layer applied to the main element and at least one intermediate layer situated between the wear protection layer and the main element. It is provided that the intermediate layer is a metallic intermediate layer applied by laser deposition welding.