Tue, 18 October, 2022
Growing pressure in the automotive industry on the reduction of particulate emissions requires urgent solutions to align to upcoming Euro 7 regulations. After considering the engine, brake discs and pads are the second most impactful system in the car. Where discs are replaced multiple times within the life of a vehicle and each disc wears up to 4 mm per face, with all of that matter (plus the worn pad material), being released into the environment. New braking surfaces are required, which can match the performance demands such as wear resistance, as well as the manufacturing demands and associated production volumes.
TWI along with Wall Colmonoy, Meritor and ASCO has launched an Innovate UK project Coated Disc – Manufacture and coating of high-performance rotors using EHLA technology (1019441) aiming to bring revolution to the brake discs with coatings applied by the latest Extreme High-speed Laser Application (EHLA) coating technology in combination with novel coating materials to tackle particulate emission challenges. In this innovative project, Wall Colmonoy will investigate and develop ‘green’ materials which are free from potentially hazardous elements. TWI will optimise the coating process. ASCO will conduct surface grinding development of the coated disc along with assess the adoption and industrialisation of the entire coating process. And finally, Meritor will conduct specialist and rigorous testing to assess the discs performance and emissions impact.
Fig 1. Consortium of Coated Disc project
The EHLA process is chosen for the coating of the brake discs because: 1) it can provide a stronger metallic bonding compared to thermal spray coating processes, 2) EHLA can provide greater economics via a high coverage rate (up to 5m2/hr) , high material efficiency (up to 90% in-process) and minimised coating thickness (down to 20µm) , 3) multi-material and dis-similar materials can be deposited using EHLA due the low dilution (as low as 5µm). An early demonstration of coated disc (ø =434 mm) is shown below with a coating thickness of 50 μm with 35 seconds processing time/side.
Fig 2. Demonstration of coated disc
The expected outcomes of the project will include:
- Novel 'green' powder formulation(s) suitable for EHLA processing
- List of requirements and strategies suitable for coated brake discs
- Optimised and robust EHLA coating and finishing procedures for new 'green' powder, generating a suitable and economically viable coating for brake discs
- Coating characterisation and emission property data of the coating
- Investigated processing and manufactring chain of EHLA coating for brake discs
The Coated Disc project has received funding from Innovate UK under No 1019441