Sustainable, rapid, and low-cost recycling of waste C/C composites for the fabrication of C/C-SiC friction materials

To achieve high-value recycling of the waste C/C composites, this work adopted a rapid and low-cost molding-in-situ reaction method, using crushed C/C powder as the primary feedstock to fabricate C/C-SiC friction materials. The results indicated that the prepared C/C-SiC friction materials can be synthesized within merely 24 h, with key properties as follows: density of 2.020 ± 0.017 g/cm³ , flexural strength of 41.61 ± 1.24 MPa, compressive strength of 126.71 ± 1.48 MPa, friction coefficient of 0.507 ± 0.017, and wear rate of (1.60 ± 0.33) × 10⁻¹ ⁴m³N⁻¹m⁻¹ . Furthermore, the C/C-SiC friction materials demonstrated excellent wear resistance in braking tests. After 30 test cycles at a rotational speed of 2880 r/min, their COF and LWR were measured to be 0.416 and 2.147 μm/cycle, respectively. This work not only mitigates soil and water pollution caused by waste C/C composites landfilling, but also provides technical support for advancing the circular economy and building a resource-saving and environment-friendly society.