Microwave dielectric properties of (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) type ceramics with ultra-low firing temperatures

A series of (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) compositions were studied in regard to the sintering behavior, phase composition, microwave dielectric properties and chemical compatibility with silver and/or aluminum for electrodes. All the (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) ceramics could be sintered below 700 °C with relative densities above 93%. Whereas the (KBi)1/2MoO4 ceramic can be sintered to a high density at around 630 °C/2 hrs with a relative permittivity ∼37, a Qf value of 4000 GHz and a temperature coefficient of resonant frequency (TCF) ∼ +117 ppm/°C. Furthermore, from the XRD analysis of co-fired ceramics, the (KBi)1/2MoO4 ceramic reacts with silver but not with aluminum at its densification temperature. The (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) type ceramics can all be considered into the new field of ultra-low temperature co-firing dielectrics for multilayer applications.