Brake Disk Hybrid Coating Metallurgical Bonding
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Solution Overview
Problem
Current brake disk manufacturing methods fail to produce durable, corrosion-resistant, and wear-resistant brake disks, especially for gray cast iron, due to issues with surface rust, wear, and corrosion, as well as health concerns related to nickel dust from certain coatings, and the limitations of existing coatings under high thermal stress.
Innovation Solution
A method involving the formation of a metal coating, such as FeCrBSi, combined with an enamel coating on the brake disk surface, where the metal coating acts as both antiwear and anticorrosion, and the enamel coating provides additional corrosion protection, using a hybrid coating process that includes roughening, applying an enamel slip, drying, and heating to achieve metallurgical bonding, thereby preventing rust and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxidic enamel coating is applied to the brake disk surface, then corrosion resistance is improved, but thermal resistance deteriorates due to glass transition at approximately 650°C causing coating creep and flow under high surface pressure
Solution Approach 1:
The patent applies a composite coating system consisting of two distinct layers: a metallurgical metal coating layer (FeCrBSi) providing thermal stability and wear resistance, and an oxidic enamel coating layer providing corrosion resistance. This composite structure allows each layer to perform its specialized function without the limitations of a single-material coating, resolving the contradiction between corrosion protection and thermal resistance.
2Strength
If thermal spraying is used to apply protective material to the brake disk surface, then wear resistance is improved, but bond durability deteriorates because only moderate roughening is possible which does not lead to a durable mechanical bond
Solution Approach 1:
The patent fundamentally changes the bonding mechanism parameter from mechanical (roughening-based) to metallurgical (diffusion-based). By heating the substrate to 1040-1060°C during coating application, the FeCrBSi coating forms a metallurgical bond through phase formation and diffusion, creating adhesion strengths exceeding 70 MPa. This parameter change enables both high wear resistance and durable bonding simultaneously.
3Reliability
If nickel-containing coatings are applied to prevent rust, then corrosion resistance is improved, but health safety deteriorates due to nickel dust release during braking
Solution Approach 1:
The patent extracts and eliminates the harmful nickel component from the coating system while retaining the beneficial corrosion protection function. The FeCrBSi metallurgical coating provides rust prevention through chromium oxide formation and the subsequent oxidic enamel layer provides additional corrosion resistance, achieving the same protective function without nickel dust release during braking operations.
4Ease of manufacture
If gray cast iron is used for brake disk production, then manufacturing cost is reduced, but surface quality deteriorates due to surface rust formation
Solution Approach 1:
The patent maintains the cost-effective gray cast iron substrate while applying a dual-layer composite coating system. The FeCrBSi metallurgical coating layer prevents rust through chromium oxide formation and provides wear resistance, while the oxidic enamel coating layer provides additional corrosion protection and surface quality. This composite approach preserves the economic advantages of cast iron while eliminating its surface rust deficiency.
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 hybrid coating method results in brake disks with significantly improved adhesion and durability, preventing separation and flaking, and extending service life to over 240,000 km without rust or noise issues, while avoiding health concerns related to nickel dust.
Implementation Method 1
a purely mechanical bond (e.g., without fusion of the surface of the main body) is formed
Implementation Method 2
the enamel coating is baked into the base material of the brake disk in order to achieve a metallurgical bond through phase formation
Implementation Method 3
The sintering of the mixture which is brought about in this way can be accomplished either in a furnace or by open flaming or by means of induction coils
Data Source
AI summary
The disclosure relates to a brake disk and a method for producing a brake disk. The method may include roughening at least some area(s) of a surface of the main body, forming a metal coating on at least some area(s) of the roughened region of the surface of the main body, applying an enamel slip to at least some area(s) of the surface of the main body, drying the applied enamel slip, and heating the main body to form the enamel coating and to join the metal coating metallurgically to the main body. The brake disk may include a main body having an enamel coating arranged at least in some area(s). A metal coating may additionally be formed on the surface of the main body, at least in some area(s), wherein the metal coating is joined metallurgically to the main body.