Dielectric Properties of Na<sub>2</sub>O Doped Cao-B<sub>2</sub>O<sub>3</sub>-SiO<sub>2</sub> System Glass-Ceramics

The behavior of dielectric and microwave properties against sintering temperature was been carried out on CaO-B 2 O 3 -SiO 2 glass-ceramics with Na 2 O addition by XRD and SEM. The results show that 0.5 wt.% Na 2 O addition is advantageous to improve the dielectric and microwave properties due to increasing the major crystalline CaSiO 3 . With further increasing Na 2 O content, α-SiO 2 is the predominant crystalline phase instead of CaSiO 3 . The CBS glass-ceramics with 0.5 wt.% Na 2 O sintered at 875°C has a bulk density of 2.51g·cm -3 , and which possesses good dielectric properties: ε r =6.2, tanδ =1.9×10 -3 (10 MHz) and low dielectric constant below 2×10 -3 over a wide frequency range. The proposed dielectrics can find applications in microwave devices, which require low dielectric loss and low dielectric constant.