A novel solid solution (K1-xNax)2Mo2O7 (0.0 ≤ x ≤ 0.3) ceramics with ultra-low sintering temperatures

The (K1-xNax)2Mo2O7 (0.0 ≤ x ≤ 0.3) ceramics with ultra-low sintering temperatures were prepared by a modified solid-state reaction method. Polyvinyl ethanol (PVA) binder was replaced by ethanol and isostatic pressing technology was used, which improved the density of the ceramics effectively and avoided the side effect of the residual PVA. When x ≤ 0.3, the (K1-xNax)2Mo2O7 ceramics are with a triclinic phase and all components can be sintered well at 450 °C. The substitution of Na+ at the K-site modified the dielectric properties of K2Mo2O7 ceramic and in particular increased the Q × f value. Among all the components, the (K0.8Na0.2)2Mo2O7 ceramic exhibited the best microwave dielectric properties with a permittivity of 8.7, a Q × f value of 50 300 GHz and a temperature coefficient of −64 ppm/°C. The (K1-xNax)2Mo2O7 (0.0 ≤ x ≤ 0.3) ceramics are very potential candidates for ultra-LTCC devices and the modified solid-state reaction method is an excellent substitution for the conventional solid-state method.