Cold sintering co‐firing of (Ca,Bi)(Mo,V)O₄–PTFE composites in a single step

Abstract

Because of large differences in the processing temperature windows between ceramics and polymers, the single-step co-sintering of microwave dielectric ceramic-polymer substrates remains challenging. In this work, a dense (Ca 0.65 Bi 0.35 )(Mo 0.65 V 0.35 )O 4 (CBMVO) ceramic was first prepared through cold sintering at 150 • C, under a uniaxial pressure of 300 MPa for 60 min with Li 2 MoO 4 (LMO) as a transient low-temperature solvent. Cold-sintered CBMVO-5 wt% LMO ceramic shows excellent microwave dielectric properties: ε r ∼ 11.4, Q × f ∼ 7070 GHz, τ f ∼ −7.4 ppm/ • C. Moreover, the optimized cold sintering process enabled the preparation of a layered co-sintered (2-2 type) CBMVO-polytetrafluoroethylene composite, which maintained excellent microwave dielectric properties and showed a good heterogeneous interface bonding. The proposed cold sintering co-firing of ceramic-polymer composites in a single step shows great potential for application in the seamless integration between ceramics and polymer substrates.

Hybrid low‐temperature sintering processes of electro‐ceramics

“…28 Due to the ultralow sintering temperature, CSP is feasible to fabricate multi-material systems, such as ceramic-polymer, ceramic-2D material, and ceramicmetal composites. [29][30][31][32][33][34][35][36] Moreover, the low sintering temperature and short holding time can effectively inhibit the exaggerated grain growth, indicating that CSP has great application potential in the preparation of nanome-ter or submicron functional ceramics. At present, CSP has successfully applied in microwave dielectric, ferroelectric, piezoelectric, target material, lithium battery, thermoelectric, and optical material.…”

“…Compared with other sintering methods, it dramatically reduces the energy consumption, which is only 1/10–1/100 of that for TTS process 28 . Due to the ultralow sintering temperature, CSP is feasible to fabricate multi‐material systems, such as ceramic–polymer, ceramic‐2D material, and ceramic–metal composites 29–36 . Moreover, the low sintering temperature and short holding time can effectively inhibit the exaggerated grain growth, indicating that CSP has great application potential in the preparation of nanometer or submicron functional ceramics.…”

Sodium molybdate‐hexagonal boron nitride composites enabled by cold sintering for microwave dielectric substrates

“…A range of works have demonstrated that novel phases and materials, such as polymers (thermoplastics and thermosets), 15–20 2D materials, 21,22 and buckminsterfullerene, 23 can all be readily incorporated into the grain boundaries of a sintered ceramic material. Previously, a number of examples have been made of the cold sintering of low‐loss dielectrics with other fillers 24,25,26–35 .…”

“…Provided there is one phase that is the major volume fraction in the composite (the matrix) that can undergo sintering, other phases (the filler) can be integrated into the body and from the composite. [9][10][11][12][13][14] A range of works have demonstrated that novel phases and materials, such as polymers (thermoplastics and thermosets), [15][16][17][18][19][20] 2D materials, 21,22 and buckminsterfullerene, 23 can all be readily incorporated into the grain boundaries of a sintered ceramic material. Previously, a number of examples have been made of the cold sintering of low-loss dielectrics with other fillers.…”