Friction mechanism analysis of copper-based composites reinforced with ball-milled and modified composite ceramic powders

• Published in: Wear 2023-09, Vol.528-529, p.204959, Article 204959
• Main Authors: Wu, Jiaqi, Li, Zhuan, Wen, Guoyuan, Gao, Zonglong, Li, Ye, Zhao, Yibo
• Format: Article
• Language: English
• Subjects: Ball milling; C/C–SiC; Composite ceramic powder; Tribo-film
• ISSN: 0043-1648; 1873-2577
• DOI: 10.1016/j.wear.2023.204959

To achieve brake pads with high-temperature resistance and low-wear, copper-matrix composites reinforced by composite ceramic powder (after high-energy ball milling) are prepared. The results reveal that the SB4 brake-pad reinforced with 10% B4C–SiC powder has an excellent friction coefficient and friction stability coefficient. This improvement can be attributed to the formation of a tribo-film (80–100 nm) with high hardness and a large range. A higher content of composite ceramic powder results in an abnormal increase in the mechanical properties of SB4, which should have decreased due to weakened interface bonding. This phenomenon can be attributed to the generation of a sufficient number of new bonds during the ball milling process, combined with the high activity of the composite ceramic powder, promotes the sintering process of the copper-matrix composite material, resulting in increased densification of the brake pad. Consequently, the incompatibility between the improvements in the mechanical properties and friction properties is reduced, and the proportion of ceramic particles in the brake pad is increased, which significantly affects the improvement in the high-temperature stability of the friction properties. The copper-matrix composites reinforced with 10% B4C–SiC powder has an excellent friction stability coefficient. A high content of composite ceramic powder results in an abnormal rebound phenomenon in the mechanical properties, which should diminish owing to the weakening of interface bonding. This is because the new bond produced during ball milling may promote sintering, thus increasing the compactness. [Display omitted] •The friction behavior of composite ceramic powder on Cu-based PM was investigated.•The new bond produced in ball milling promotes the sintering densification of Cu-based PM brake pads.•There is a rebound phenomenon for the mechanical properties of SB4 that should have declined.•The tribo-film is composed of B2O3, FeO or Fe2O3, little graphite and SiC.•The relationship between formation of tribo-film and wear mechanism was explored.