Brake Disc Surface Layer Composition for Corrosion and Wear Resistance
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Solution Overview
Problem
Brake discs made of gray cast iron suffer from high corrosion tendency and wear, leading to early replacement, while ceramic materials offer long service life but are costly, and existing wear protection layers fail to provide lasting corrosion protection and are prone to nickel oxide formation, complicating layer thickness measurement.
Innovation Solution
A surface layer composed of a high-alloy austenitic steel matrix with embedded hard material particles, applied via thermal process, which reduces nickel content and maintains non-magnetic properties, allowing for magnetic inductive layer thickness measurement and effective wear protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wear protection layer with high nickel content is applied to gray cast iron brake discs, then corrosion resistance and wear protection are improved, but nickel oxide formation increases and layer thickness measurement becomes complicated
Solution Approach 1:
The patent changes the chemical composition parameters of the wear protection layer by limiting nickel content to a maximum of 1.5 wt.% and increasing chromium content to a minimum of 13 wt.%, thereby reducing nickel oxide formation while maintaining corrosion resistance through chromium enrichment
2Reliability
If a wear protection layer is applied to gray cast iron brake discs, then wear resistance is improved, but the cost increases significantly compared to pure cast iron
Solution Approach 1:
The patent applies wear protection locally only to the friction surfaces of the brake disc where it is most needed, rather than coating the entire component, thereby reducing material consumption and manufacturing cost while maintaining wear resistance at critical locations
Solution Approach 2:
The patent creates a composite structure combining gray cast iron base material with a optimized steel layer containing hard particles, achieving high wear resistance through material combination rather than using expensive ceramic materials throughout the entire brake disc
3Object-generated harmful factors
If existing corrosion protection coatings are applied to brake discs, then aesthetic appearance is improved, but wear protection is insufficient as coatings are worn away during braking operations
Solution Approach 1:
The patent merges corrosion protection and wear protection functions into a single integrated surface layer with optimized composition (low nickel, high chromium content) and embedded hard particles, eliminating the need for separate coating layers and ensuring both functions are provided simultaneously at the friction surface
4Reliability
If high-alloy chromium-nickel steel is used for the wear protection layer, then corrosion resistance is improved, but stress and vibration corrosion resistance deteriorates compared to chromium steel
Solution Approach 1:
The patent changes the alloy composition parameters by reducing nickel content to maximum 1.5 wt.% and increasing chromium content to minimum 13 wt.%, creating a chromium-enriched steel layer that provides both corrosion resistance and improved resistance to stress and vibration corrosion
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, durable wear protection layer that prevents corrosion and wear, enabling non-destructive layer thickness measurement and reducing nickel oxide formation, thus extending the service life of brake discs.
Implementation Method 1
a surface layer for a base body made of gray cast iron or ferritic steel, which can be applied to the base body by a thermal deposition process
Data Source
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AI summary
A surface layer (8) (8) for a base body (2, 102) made of gray cast iron or ferritic steel, which is applied or can be applied to the base body (2, 102) by a thermal deposition process, comprises a matrix of a high-alloy austenitic steel and hard particles (9, 109) (9) embedded in this matrix. The high-alloy austenitic steel of the matrix consists of at least 8 wt.% manganese, at least 13 wt.% chromium, a maximum of 5 wt.% other trace elements besides iron, wherein the proportion of nickel is limited to a maximum of 1.5 wt.%, and the remainder iron. Also specified are a base body (2, 102) (2) made of gray cast iron or ferritic steel, base bodies (2, 102) with such a surface layer (8) (8), and a method for manufacturing a brake body for a friction brake of a motor vehicle.