Microwave Dielectric Properties and Low Temperature Sintering of Sm_2Si_2O_7 Ceramic for Substrate Applications

摘要

The Sm_2Si2O_7 ceramics were synthesized by solid-state ceramic route. The calcination and sintering temperature of Sm_2Si_2O_7 were optimized for the best properties. The crystal structure and microstructure of the ceramic were studied by X-ray diffraction and scanning electron microscopic methods. The low frequency dielectric properties were studied at 1 MHz. The dielectric properties of the ceramic were measured in the microwave frequency range by the cavity perturbation method. Sm_2Si_2O_7 has ε_r. = 12.5, tan 5 = 8 × 10~-4 , and T_ε = +63 ppm/℃ at 1 MHz and a relative permittivity of 10 and tan 8 of 6 × 10~3 in the microwave frequency range. The effect of addition of various low loss glasses such as 50ZnO-50B2O3 (ZB), 60ZnO-30B_2O_3-10SiO_2 (ZBS), 27B_2O_3-35Bi_2O_3-6SiO_2-32ZnO (BBSZ), 22.2MgO-22.2Al_2O_3-55.5SiO_2 (MAS), 35.1Li_2O-31.7B_2O_3-33.2SiO_2 (LBS) and 20Li_2O-20MgO-20ZnO-20B_2O_3-20SiO_2 (LMZBS) on the microwave dielectric properties of Sm_2Si_2O_7 was also investigated. It was found that the addition of 15 wt% LBS glass reduced the sintering temperature from 1375℃ to 975℃ with ε_r = 9.89 and tan S = 0.024. Fifteen weight percent LMZBS glass ceramic decreased the sintering temperature to 950℃ with ε_r = 9.09 and tan 8 = 0.009. The results show that Sm_2Si_2O_7 mixed with suitable amounts of selected glasses is a promising material for microwave substrate applications.