Cold-Sprayed Brake Disc Coating to Prevent Wear and Warping
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Solution Overview
Problem
Brake discs used in disc brakes face issues with high wear, corrosion susceptibility, and heat generation, leading to inefficiencies and material degradation.
Innovation Solution
A method involving cold gas spraying of a particle mixture comprising 25-75% metal matrix materials (such as iron-based, nickel-based, or titanium alloys) and 75-25% carbide materials (like tungsten carbide or titanium carbide) onto the brake disc base body or intermediate layers, enhancing wear resistance, corrosion resistance, and reducing heat-induced warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional spraying processes are used, then coating application is achieved, but heat input causes base body distortion
Solution Approach 1:
The patent replaces thermal-based coating processes with a mechanics-based cold gas spraying process. Instead of relying on thermal energy to melt and deposit coating material, the process uses mechanically accelerated particles delivered at supersonic speeds. The kinetic energy of the particles provides the bonding mechanism, substituting thermal fields with mechanical fields and eliminating heat-induced base body distortion while maintaining effective coating application.
2Weight of moving object
If lightweight materials are used for brake disc base body, then weight is reduced, but wear resistance and heat resistance of friction surface are insufficient
Solution Approach 1:
The patent uses composite materials in the friction surface layer combining metal matrix with carbide particles to provide exceptional wear resistance and heat resistance. This allows lightweight base body materials to be used while the composite coating compensates for the lower inherent durability of lightweight materials through the hard carbide components embedded in the metal matrix structure.
Solution Approach 2:
The patent applies local quality by creating a friction surface layer with specifically engineered properties only where needed - on the friction surfaces of the brake disc. The base body can be made of lightweight material with different properties, while the localized friction surface layer provides the necessary wear resistance, heat resistance, and durability through the composite particle structure, allowing each region to have optimized properties for its specific function.
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 significantly reduces wear by up to 99% and improves corrosion resistance, allowing for lighter, cost-effective production of brake discs with minimized risk of delamination and warping, while avoiding environmentally hazardous materials.
Implementation Method 1
One such process is cold gas spraying (also called kinetic coating, cold gas spraying, cold spray, kinetic metallization, or kinetic fusion). In cold gas spraying, the coating material is in powder form and is applied to the substrate at very high speed, in particular supersonic speed. A process gas is used for this purpose, which is fed to a spray gun under high pressure and heated to temperatures of up to approximately 1200°C. The subsequent expansion of the gas in a convergent-divergent nozzle (Laval nozzle) causes the process gas to accelerate to supersonic speeds and cool down significantly in the process. The spray powder injected into the nozzle is also accelerated to supersonic speeds and, due to its high kinetic energy, bonds firmly to the substrate.
Implementation Method 2
The spray powder injected into the nozzle is also accelerated to supersonic speeds and, due to its high kinetic energy, bonds firmly to the substrate.
Implementation Method 3
The spray powder injected into the nozzle is also accelerated to supersonic speeds and, due to its high kinetic energy, bonds firmly to the substrate.
Data Source
Figure 1
Figure 2~3
AI summary
In a process for manufacturing a brake disc (1), a friction surface layer (10a, 10b) is sprayed onto the base body (2) or onto an intermediate layer (12a, 12b) applied to the base body (2) by cold gas spraying of a particle mixture consisting of 25 to 75 wt.% of a metal matrix material and 75 to 25 wt.% of a carbide material. The metal matrix material consists of an iron-based alloy, a nickel-based alloy, titanium, or a titanium alloy. The carbide material consists of tungsten, titanium, iron, silicon, chromium, or niobium carbide.