Cold sintered LiMgPO4 based composites for low temperature co‐fired ceramic (LTCC) applications

Cold sintered, Li2MoO4‐based ceramics have recently been touted as candidates for electronic packaging and low temperature co‐fired ceramic (LTCC) technology but MoO3 is an expensive and endangered raw material, not suited for large scale commercialisation. Here, we present cold sintered temperature‐stable composites based on LiMgPO4 (LMP) in which the Mo (and Li) concentration has been reduced, thereby significantly decreasing raw material costs. Optimum compositions, 0.5LMP‐0.1CaTiO3‐0.4K2MoO4 (LMP‐CTO‐KMO), achieved 97% density at <300 °C and 600 MPa for 60 mins. Raman spectroscopy, X‐ray diffraction, scanning electron microscopy and energy dispersive X‐ray mapping confirmed the coexistence of end‐members, LMP, CTO and KMO, with no interdiffusion and parasitic phases. Composites exhibited temperature coefficient of resonant frequency ~ –6 ppm/°C, relative permittivity ~ 9.1 and Q×f values ~ 8,500 GHz, properties suitable for LTCC technology and competitive with commercial incumbents.