Abstract:
Ca
1+xSm
1−xAl
1−xZr
xO
4 (
x=0.1, 0.2, 0.3, 0.4) microwave ceramics in the lamellar perovskite structure were fabricated by the traditional solid-phase synthesis method. The effect of the Ca/Zr co-substitution on the crystal structure, microstructure, and dielectric characteristics of the microwave ceramics were investigated by X-ray diffraction (XRD), Raman spectra, electron backscatter diffraction (EBSD), energy dispersive spectroscopy (EDS), and vector network analysis (VNA). In the results, the cell parameters (
a,
c), cell volume (
Vcell), and theoretical polarizability (
αtheo) increase with the increase of
x, leading to the increase of the dielectric constant (
εr) and resonant frequency temperature coefficient (
τf); meanwhile, a moderate amount of CaO secondary phases can improve the quality factor (
Q×f). Ca
1.2Sm
0.8Al
0.8Zr
0.2O
4 (
x=0.2) ceramics show the excellent microwave performance as
εr=20.16,
Q×
f=72489, and
τf = −3.46×10
−6·℃
−1.