Enhancement of structural and microwave properties of Zn2+ ion-substituted Li2MgSiO4 ceramics for LTCC applications

In this study, Zn²⁺-substituted Li₂MgSiO₄ ceramics (Li₂(Mg_1-xZn_x)SiO₄, x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized using a traditional solid-state method. A fixed amount of LiF sintering aid (1.5 wt%) was added to the ceramics for decreasing the sintering temperature and adjusting their microwave dielectric properties. X-ray diffraction (XRD) results revealed no secondary phases, and scanning electron microscopy (SEM) data suggest that the Zn²⁺ ion substitution increased the size and uniformity of the grains, thereby affecting the densification of the prepared ceramics. The maximum bulk density (2.94 g/cm³) was found in a Zn²⁺ ion-substituted ceramic with x = 0.10 at a relative density of 94.2% (compared with the XRD theoretical density). Excellent microwave dielectric properties (ε_r = 6.28, Q × f = 50400 GHz, and τ_f = ?145 ppm/°C) can also be obtained at this zirconium content. We believe that the developed ceramics are promising for use as antenna substrates or transmit/receive modules in low-temperature co-firing ceramic applications.