Hot-pressing sintered AlN-BN ceramics with high thermal conductivity and low dielectric loss

In this paper, AlN-BN ceramics with high thermal conductivity and low tan δ were prepared by hot-pressing sintering for 2 h using YF₃ as sintering aids. Effect of sintering temperature and YF₃ content on microstructure and properties of samples were investigated. The results show that the apparent porosity of AlN-BN ceramics with 3 wt% YF₃ reached 0.453‰, and the thermal conductivity of AlN-BN ceramics reached up to 112 W m⁻¹ K^{− 1}. And the flexural strength and fracture toughness of the sample were 286 ± 9 MPa and 4 ± 0.1 MPa m^1/2, respectively. The dielectric constant of AlN-BN ceramics increased and the tan δ decreased firstly and then increased with the increase of YF₃. The dielectric loss of AlN-BN with 3 wt% YF₃ reached 5.04 × 10⁻⁴, and the dielectric constant was 7.82 at 1 MHz.