Fabricating high-performance boron carbide ceramics with silicon cutting waste as a sintering aid: Insights into densification mechanism and property enhancement

This study proposes a novel approach for fabricating high-performance B 4 C ceramics using crystalline silicon cutting waste as a sintering aid. The influence of the content and composition of the cutting waste on the sintering behavior and properties of B 4 C ceramics is systematically investigated, and the densification mechanism, the strengthening and toughening mechanism are studied. Results indicate that the B 4 C ceramic with an 8 wt% addition of raw crystalline silicon cutting waste achieves a relative density of 98.77%, a hardness of 31.63 GPa, a flexural strength of 339.62 MPa, and a fracture toughness of 3.406 MPa m 1 / 2 . At the same addition level, using deoxidized cutting waste further enhanced the properties, yielding a relative density of 98.83%, a hardness of 33.02 GPa, a flexural strength of 344.37 MPa, and a fracture toughness of 3.847 MPa m 1 / 2 . Si within the cutting waste reacts to form SiC during sintering, contributing to improve densification and mechanical properties. SiO 2 within the cutting waste reacts to form gaseous products, leading to pore formation and consequent degradation of the performance. Appropriate addition of cutting waste can enhance the densification, and can strengthen and toughen the ceramics by changing the fracture mode, consuming more tearing energy and inducing the crack deflection and branching. This work not only provides an environmentally friendly and economically viable high-valued pathway for recycling crystalline silicon cutting waste but also offers a novel strategy for fabricating high-performance B 4 C ceramics.