Influence of Sn4+ substitution for Si4+ on the microwave dielectric properties of Mg2Al4Si5−xSnxO18 ceramics

The Mg 2 Al 4 Formula: see textSn x Formula: see text (Formula: see text) ceramics were successfully synthesized via the solid-state reaction method. The XRD results show that the main phase of the ceramics is Mg 2 Al 4 Si 5 Formula: see text. When Formula: see text, there is a second phase of Al 2 SiO 5 . With the increase of x, the content of Formula: see text gradually increased, the Al 2 SiO 5 phase disappeared, and the SnO 2 and MgAl 2 O 4 phases appeared. In addition, the cell volume of the ceramic changes with the increase of x, which indicates that partial Formula: see text successfully enters the lattice with ion substitution and lattice distortion. The relative density and Formula: see text are highly correlated. The quality factor (Qf) is not only affected by the relative density but also by the symmetry of the Si 4 Al 2 ring. The bond strength as an evaluation of the stability of the crystal structure determines the magnitude of Formula: see text. Good microwave dielectric properties were achieved for samples at Formula: see text with sintering at 1400 ∘ C: Formula: see text, Formula: see textFormula: see textGHz and Formula: see textFormula: see textppm/ ∘ C, demonstrating that Mg 2 Al 4 Formula: see textFormula: see textFormula: see text ceramics are an ideal candidate for microwave electronics.