Brake Disc Nickel-Free Steel Layer for Wear and Rust Resistance
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Solution Overview
Problem
Traditional brake discs made of gray cast iron or steel suffer from excessive wear and surface oxidation, leading to rust formation, and existing protective coatings are prone to flaking, causing the release of nickel particles.
Innovation Solution
A brake disc with a base layer of nickel-free steel, optionally with a surface protective coating of carbides, is manufactured using techniques like laser deposition or thermal spray, to reduce nickel particle release and enhance wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional protective coatings containing nickel are applied on brake discs, then wear resistance is improved, but nickel particles are released causing health concerns
Solution Approach 1:
The protective coating is segmented into multiple layers: a nickel-containing adhesive layer for bonding, a nickel-free intermediate layer to prevent nickel release, and a nickel-free wear-resistant top layer. This segmentation allows each layer to perform its specific function while eliminating nickel particle release to the environment.
Solution Approach 2:
A nickel-free intermediate layer is introduced as a mediator between the nickel-containing adhesive layer and the nickel-free wear-resistant top layer. This intermediate layer prevents nickel diffusion and particle release while maintaining the bonding and protective functions of the coating system.
2Object-generated harmful factors
If nickel-free steel is used for the brake disc, then nickel particle release is reduced, but wear resistance and mechanical strength deteriorate
Solution Approach 1:
The solution employs composite materials by applying a multi-layer protective coating system on the nickel-free steel substrate. The coating composite includes nickel-containing adhesive layer, nickel-free intermediate layer, and nickel-free wear-resistant top layer, combining the benefits of nickel-free base material with the protective properties of coated surfaces.
3Reliability
If protective coatings are applied to prevent surface oxidation, then corrosion resistance is improved, but coating flaking occurs leading to nickel release
Solution Approach 1:
The protective coating is segmented into multiple specialized layers, each performing a specific function: the adhesive layer provides bonding and initial corrosion protection, the intermediate layer prevents nickel release and enhances adhesion, and the top layer provides wear and corrosion resistance. This segmentation eliminates flaking by ensuring proper adhesion at each interface.
Solution Approach 2:
The coating system uses controlled parameter changes in nickel content across layers (nickel-containing adhesive layer → nickel-free intermediate layer → nickel-free top layer) to achieve both corrosion resistance and prevention of nickel particle release, while maintaining coating integrity and preventing flaking.
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 effectively reduces nickel particle release while maintaining adequate thermal and mechanical performance, improving wear resistance and mechanical strength, and reducing resource consumption.
Implementation Method 1
depositing a base layer (30) composed of nickel-free steel, in particular by a laser deposition technique
Implementation Method 2
depositing over said base layer (30) a surface protective coating (3) composed of carbides, in particular by a thermal spray technique
Data Source
AI summary
Provided is a brake disc for a disc brake having a braking band made of gray cast iron or steel, provided with two opposite braking surfaces, each of which defines at least partially one of two main faces of the brake disc. The brake disc is provided with a base layer composed of a totally nickel-free steel that covers at least one of the two opposite braking surfaces of the braking band. The totally nickel-free steel of the base layer is composed of 10% to 15% chromium (Cr), at most 1% silicon (Si), at most 4% manganese (Mn), 0.16% to 0.5% carbon, and iron (Fe) as a balance.