Stable high thermal conductivities in BaTiO_3 ceramic composites utilizing core-shell Ag@BaTiO_3 particles

摘要

Ceramic/metal composites have drawn much attention in heat dissipations due to excellent performances, however, issues rise with the uncontrollable architecture and unstable properties resulting from metal-particle fusions at the high-temperature sintering. This study reports a BaTiO3 (BT) composite at a high Ag loading of 60 vol% with a stable composite architecture achieved by utilizing core-shell Ag@BT particles. Conformal-coated Ag@BT particles are prepared by simultaneous hydrolysis. The BT shell is vital in keeping Ag particles separately distributed and the shape well-retained in the BT matrix before and after the sintering to exhibit controllable structures. A high thermal conductivity of 84 W/mK is obtained in the composite at 25 degrees C, 35-fold enhanced compared with that of the BT ceramic of 2.4 W/mK. Low thermal barrier resistances as well as the nonpercolative behavior attributing to high thermal conductivities are owing to the unique composite architecture. The com-posite exhibits small fractures at Ag-BT interfaces while no macro fractures across the material are observed after the thermal cycling test. This study presents a BT/Ag@BT composite for various heat dissipation applications.