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

Abstract

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 commercialization. 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 minutes. 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 ~8500 GHz, properties suitable for LTCC technology and competitive with commercial incumbents.

Dynamics of the Chemically Driven Densification of Barium Titanate Using Molten Hydroxides

“…This approach represents a major breakthrough in sintering science and can be extended to several other inorganic materials as a cost-and energy-efficient process. 9,27,28 which also enables the fabrication of high-performance functional devices at record low temperatures. 29−31 In spite of widespread use of molten salts for synthesis and crystal growth in both open or closed systems (as hydrothermal molten salt (HyMoS) 32 or hydroflux 33 when mixed with approximately 30−40 wt % water), fundamental knowledge of chemical mechanisms is still limited as the use of in situ structural characterization techniques in this environment is still a challenge.…”

Direct ink writing of bismuth molybdate microwave dielectric ceramics

“…In Figure 4d, the existing grains have assumed an elongated/columnar structure, consistent with the remarks above. Such behaviour is expected to have a significant impact on microwave performance of the resulting parts, since porosity will effectively reduce εr and increase in tanδ [12,40]. tanδ is greatly influenced by the presence of moisture within the ceramic bodies [41] which resides on the surface of internal pores.…”

“…LTCCs can be densified at temperatures well below 1000°C and allow co-sintering with low cost electrode materials, such as silver, copper or gold [8][9][10][11]. This will benefit electronics manufacture by reducing the associated carbon footprint, since lower processing temperatures would require less energy consumption and CO2 emissions [12].…”

Sintering Characteristic, Structure, Microwave Dielectric Properties and Compatibility with Ag of Novel 3MgO-B2O3-xwt% Ba(CuB2)O5-ywt% H3BO3 Ceramics

“…In particular, with the emergence of 5G largescale antenna (Massive MIMO) technology, the number of antennas will increase exponentially. The demand of lters for signal frequency selection and processing will grow with the passage of time, thus the demand for low-temperature co-red ceramics (LTCC) will also increase signi cantly [8][9][10][11][12][13]. LTCC technology requires the dielectrics co re with high conductivity material electrodes.…”