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Improved Braking Performance of Cu-Based Brake Pads by Utilizing Cu-Coated SiO2 Powder

Abstract The braking performance of copper-based brake pads containing Cu-coated SiO2 and uncoated SiO2 was tested on a reduced-scale dynamometer. Results showed that both the stability of the friction coefficient and the wear resistance are improved and the fade phenomenon of the friction coefficient is effectively alleviated during continuous emergency braking (350 km/h, 0.48 MPa) by introducing Cu-coated SiO2 into the copper-based brake pad. The better braking performance is closely related to the improved interfacial bonding and the firm pinning of SiO2 particles on the friction surface. The copper coating on SiO2 reduces the spalling of SiO2 particles from the copper matrix during the braking process. Therefore, for the sample containing Cu-coated SiO2, the SiO2 particles pinned on the friction surface act as trapping sites for wear debris, promoting the formation of secondary plateaus. As a result, the existence of stable primary and secondary plateaus in the braking process promotes the stability of the friction coefficient.