Cold sintered (1-x)Na₂WO₄-xBN microwave dielectric ceramics with enhanced thermal conductivity

Boosting thermal conductivity in microwave dielectric ceramics is indispensable for cutting-edge applications, such as 5G/6G communication and electronic packaging. However, it remains a challenge to improve thermal conductivity while sustaining microwave dielectric properties. In this work, (1-x)Na₂WO₄-xBN, microwave dielectric ceramics with high thermal conductivity, are cold sintered at 150°C under a pressure of 220 MPa. The designed formulations fabricated using cold sintering process show high relative densities of >90%. Structural and microstructural analysis indicate that (1-x)Na₂WO₄-xBN composites are well sintered without any impurities under cold sintering conditions. The composite with 25% BN shows a thermal conductivity of 4.4 W m⁻¹ K⁻¹, 266% higher than that of pure Na₂WO₄, while exhibiting excellent temperature stability (TCF = −23 ppm/°C) and good microwave dielectric properties with ε_r = 5.1 and Q×f = 10,400 GHz. Current research provides an approach for the fabrication of low temperature sintered microwave dielectric ceramics with enhanced thermal conductivity.