Friction materials inspired by characteristics of bio-based silica and its hardening process

Designing and developing composites with excellent mechanical, friction, and durability properties at low cost has long been highly desirable for the applications of friction materials. Herein, we employed a cost-effective method to obtain bio-based silica (RHC-SiO2) from gasified rice husk carbon (RHC). Subsequently, inspired by the characteristics of RHC-SiO2 and its hardening process, we report a simple and efficient so-called “hybrid pressing and sintering molding” method for manufacturing copper-based friction materials (CFMs). The CFM-R4 (CFM with 4% RHC-SiO2) possesses a unique combination of high hardness (55.50 H V), low density (0.62 g/cm3), low wear rate (0.081%), suitable friction coefficient (0.26), and good durability. Based on the cost-effective method, the increased and decreased stages of RHC-SiO2 yield were determined mainly by reaction rate and compatibility, respectively. Compared with CFM-0 (CFM without SiO2), the CFM with RHC-SiO2 possesses better mechanical and friction properties. In view of high-performance and eco-friendly, such CFM with RHC-SiO2 would hold a promising application in friction fields such as transmission, differential, and synchronizer.