Low-Temperature Sintering and Microwave Dielectric Properties of CaWO₄-Mg₂SiO₄Ceramics

Abstract

The effect of V2O5addition on the microstructures and the microwave dielectric properties of 0.9CaWO4-0.1Mg2SiO4(9CWMS) ceramics prepared by conventional solid-state routes have been investigated. The V2O5were selected as liquid phase sintering aids to lower the sintering temperature of 9CWMS ceramics. A small amount of V2O5(0.25~1 wt%) were used for sintering aid and led to high densification at 1050°C. The dielectric properties of 9CWMS ceramics with V2O5additions are strongly dependent on the densification, the microstructure. As the amount of V2O5additives increased from 0.25 to 1.0 wt%, the dielectric constantsεrdecreased following the trend with density. The quality valuesQdecreased with the increase of V2O5amount for all sintering temperatures. The 0.25 wt% V2O5-doped 0.9CaWO4-0.1Mg2SiO4ceramicssintered at 1080°C for 2 h had the optimum dielectric properties: εr= 5.7;Q×f= 73000 (at 14 GHz).

Effect of nano aluminum nitride filler on mechanical, thermal, and dielectric properties of the glass/mullite composites for low‐temperature co‐fired ceramic applications

“…The optimum densification temperatures were 825 • C for the M55 (2.63 g/cm 3 , AP = 0.19% and WA = 0.17%), 800 • C for the M55-1 (2.61 g/cm 3 , AP = 0% and WA = 0%), 800 • C for the M55-2.5 (2.57 g/cm 3 , AP = 0.27% and WA = 0.09 %), 825 • C for the M55-5 (2.53 g/cm 3 , AP = 0.12% and WA = 0.04%), and 825 • C for the M55-10 (2.48 g/cm 3 , AP = 0.72% and WA = 0.28%). Also, relative densities were found by dividing the bulk densities of the compositions by their theoretical densities as determined by the logarithmic mixture equation, 25 using the theoretical densities of 3.13 g/cm 3 for mullite, 26 2.43 g/cm 3 for glass, 24 and 3.26 g/cm 3 for AlN. 12 The relative densities of the M55, M55-1, M55-2.5, M55-5, and M55-10 were 99.2%, 99.0%, 97.3%, 95.4%, and 92.9%, respectively, which indicates that AlN addition decreases the relative densities.…”

Novel Low‐Permittivity (Mg1−xCux)2SiO4 Microwave Dielectric Ceramics

“…Figure 5 showed the dielectric constant, quality factor, and τ f of the (Mg 0.95 Cu 0.5 ) 2 SiO 4 with 12% B 2 O 3 -LiF ceramics sintered at various temperatures for 4 h, respectively. e ε r is mainly dominated by the structural characteristics, dielectric polarizability, and relative density of the ceramics [11][12][13]. It can be seen from Figure 5(a) that the variation trend of ε r with sintering temperatures was not in agreement with that of relative density.…”