Insights Into the Microstructure and Dielectric Properties of Cold Sintered NaCa2Mg2V3O12 Based Composites

Abstract

Cold sintering process (CSP) was successfully employed to fabricate (1 − x) NaCa2Mg2V3O12-xNaCl [abbreviated as (1 − x) NCMVO-xNaCl] microwave dielectric ceramics. (1 − x)NCMVO-xNaCl ceramics prepared at 200°C and at a pressure of 450 MPa had a high relative density of 80–94%. X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and Raman spectroscopy showed that both NCMVO and NaCl phases co-exist in all composite ceramics without forming any secondary phase. Further, dependence of microstructure and dielectric properties on cold sintering temperature and duration were investigated in detail and their optimized values to obtain maximum density of ceramic composites were 200°C and 50 min, respectively. (1 − x)NCMVO-xNaCl (x = 0.4–0.7) composites have relative permittivity (εr) in the range of 6.9–7.4, and a reasonably high microwave quality factor (Q × f) of 5,000 to 13,830 GHz.

Influence of sintering characteristics and structural properties on the microwave dielectric properties of non-stoichiometric Ca3Mn2+xGe3O12+δ (x = 0–0.2) ceramics

“…Specifically, the Raman peaks of CM 2.1 G at 804.5 cm −1 are caused by the antisymmetric stretching mode, A 1g , of Ge–O in the tetrahedron. 29–31…”

“…Specifically, the Raman peaks of CM 2.1 G at 804.5 cm À1 are caused by the antisymmetric stretching mode, A 1g , of Ge-O in the tetrahedron. [29][30][31] The intrinsic effect of the microstructure on the dielectric properties can be investigated using the A 1g Raman modes. These internal modes represent tensile vibrational modes with the highest Raman intensities, which are related to intrinsic dielectric losses.…”

Cold sintering co‐firing of (Ca,Bi)(Mo,V)O4–PTFE composites in a single step

“…The preparation of dense ceramics by cold sintering depends on the solubility of the powder in water and on many external factors, including the amount of water added, and the applied pressure, temperature, and holding time. [25][26][27][28][29][30] The effect of external factors on densification was investigated to obtain an optimized process. The influence of water addition on ceramic cold sintering was studied.…”