B₂O₃ as an effective additive for cold sintering of MgTiO₃

In the present study, B₂O₃ has been introduced as an effective additive for the cold sintering of MgTiO₃ as a microwave dielectric ceramic. Furthermore, the effects of various cold sintering parameters, including cold sintering temperature, post-annealing temperature, sintering process time, and B₂O₃ quantity have been investigated. The results proved that high-quality samples with a relative density of more than 96% can be obtained by using 15 wt% B₂O₃ and cold sintering at 200 °C under an applied pressure of 250 MPa for 1 h and post annealing at 1100 °C. X-ray diffraction (XRD) analysis confirmed the absence of any reaction between the two phases. Moreover, the MgTiO₃- 15 wt% B₂O₃ ceramics show excellent microwave dielectric properties, including a low relative permittivity (ε_r) of 14.5, a high-quality factor (Q×f) of 39,000 GHz, and a temperature coefficient of frequency (TCF) value of −54.36 ppm/°C.