β-CaSiO3 ceramics with Si3N4 addition were prepared by pressureless-sintering.
Si3N4 had great effect on the mechanical properties of the β-CaSiO3 ceramics.
β-CaSiO3 ceramics with 3 wt% Si3N4 revealed a flexural strength of 157.2 MPa.
Si3N4 can be used as sintering additive by being oxidized to form SiO2.