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 with regard to their sintering behaviour, phase composition, microwave dielectric properties and chemical compatibility with silver and/or aluminium electrodes. All the (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) ceramics could be sintered below 700 C with relative densities above 93%. The (KBi)1/2MoO4 ceramic could be sintered to a high density at around 630 C/2 h with a relative permittivity of about 37, a Qxf value of 4000 GHz and a temperature coefficient of resonant frequency (TCF) of about +117 ppm/C. From XRD analyses of the co-fired ceramics, (KBi)1/2MoO4 reacted with silver but not with aluminium at its densification temperature. The (ABi)1/2MoO4 (A = Li, Na, K, Rb, Ag) type ceramics can all be considered for the new field of ultra-low temperature co-firing dielectrics for multilayer applications.