High-Performance Cold Spray Coating for Particle Emission Reduction of Gray Cast Iron Brake Discs

With a high-performance cold spray coating made with the Impact Cold Spray System EvoCSII, particle emissions can be reduced drastically by up to 90%. Cold spray coatings on brake discs passed even harshest crack formation tests with corrosion tests in between without any delamination or severe cracking behavior. The performance of the coating was evaluated in terms of corrosion resistance, wear resistance, and tensile bond strength between the coating and the brake disc. The cold gas sprayed composite coating of the cast iron brake disc showed a >95% reduction in wear in the SAE J2522 test. Supplementary, 720 h of salt spray chamber tests were successfully completed without any corrosion even after performing additional wear tests. The better performance of Cold Spayed coated brake discs compared to high-speed laser cladding (HPLC) led to the technical qualification at several automotive OEMs and is their preferred coating technology for brake discs. This choice is supported by a robust manufacturing (coating) process without any thermal stress to the brake discs, which avoids any kind of mechanical deformation.