Mechanical strength and sound absorption performance of porous B ₄ C ceramic

Abstract Porous B 4 C ceramics with varying densities and porosities were synthesized by a rapid hot‐press sintering method at different temperatures and pressures. Their sound absorption performance and mechanical properties were investigated, showing that the mechanical strength and sound absorption coefficient can be tuned simultaneously by controlling the sintering parameters. The sound absorption coefficient of porous B 4 C ceramics was found to be closely dependent on porosity, density, pore size, airflow resistance, and thickness. Furthermore, the sound absorption coefficient of B 4 C ceramics can be fine‐tuned to a wider range of frequencies (500–6400 Hz) by combining them with aluminum foam and an air gap, which can result in an average absorption coefficient (AAC) of 0.49 and a maximum sound absorption coefficient of 0.997 within the frequency range of 500 to 6400 Hz, approaching 1. The porous B 4 C ceramics also exhibit excellent compressive strength, reaching up to 745.30 MPa, the fracture toughness was 0.86 MPa m 1/2 , and with the load increased, the failure displacement of the ceramic reached 0.28 mm. The stress transition from compressive stress to tensile stress in the lattice, and the crystal structure from crystalline to a disordered structure caused by the variation of the pressures at 1700°C.