Low temperature sintering and microwave dielectric properties of LiMBO3 (M = Ca, Sr) ceramics

LiMBO3 (M=Ca, Sr) ceramics have been prepared by a traditional ceramic process. The microstructure and chemical compatibility with Ag were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Microwave dielectric properties were measured with a network analyzer. LiMBO3 (M=Ca, Sr) ceramics could be densified at 800 degrees C. Secondary phases appeared with the further increase hi sintering temperature due to the possible evaporation of boron. The Q x f values of LiMBO3 (M=Ca, Sr) strongly depended on sintering temperature, and decreased remarkably with the further increase in sintering temperature higher than 800 degrees C. Optimized microwave dielectric properties with epsilon(r) = 8.7, Q x f=75000 GHz, tau(f) = 150 ppm/degrees C and epsilon(r) = 8.6, Q x f= 60000 GHz, tau(f) = -39 ppm/degrees C could be obtained for LiCaBO3 and LiSrBO3, respectively, after sintering at the 800 degrees C for 2 h. LiMBO3 (M = Ca, Sr) ceramics could be chemically compatible with Ag after sintering at 800 degrees C/2 h. (C) 2016 Published by Elsevier Ltd and Techna Group S.r.l.