Low-temperature sintering and microwave dielectric properties of H₃BO₃-added 0.8BaSi₂O₅–0.2Ba₃(VO₄)₂ composite ceramics

In this study, 0.8BaSi₂O₅–0.2Ba₃(VO₄)₂ composite ceramics were successfully synthesized with the addition of H₃BO₃ (x = 2–6 wt%) at lower temperatures using a solid-state sintering process. The phase composition and crystal structure were analyzed by X-ray diffraction, which confirmed that the addition of H₃BO₃ did not change the phase structure of the ceramics. The composite ceramics still consisted of BaSi₂O₅ and Ba₃(VO₄)₂. The addition of H₃BO₃ effectively reduced the sintering temperature of the composite ceramics while maintaining the excellent microwave dielectric properties. The sintering temperature of the 0.8BaSi₂O₅–0.2Ba₃(VO₄)₂ ceramic was reduced from 1140 to 950 °C with the addition of 3 wt% H₃BO₃. The 0.8BaSi₂O₅–0.2Ba₃(VO₄)₂–3wt%H₃BO₃ composite ceramics, sintered at 950 °C for 4 h, exhibited the optimal microwave dielectric properties, with values of ε_r = 9.23, Q×f = 33,026 GHz, and τ_f = − 4.85 ppm/°C. XRD and EDS energy spectra revealed no chemical reaction between the composite ceramic and silver, highlighting its potential as a candidate for low-temperature co-fired ceramic (LTCC) applications in communications.