In this paper, we present a method to create a highly sensitive piezoelectric quasi 1–3 composite using a thermoplastic material filled with a piezoelectric powder. An up-scalable high-temperature dielectrophoresis (DEP) process is used to manufacture the quasi 1–3 piezoelectric polymer-ceramic composites. For this work, thermoplastic cyclic butylene terephthalate (CBT) is used as a polymer matrix and PZT (lead zirconium titanate) ceramic powder is chosen as the piezoelectric active filler material. At high temperatures, the polymer is melted to provide a liquid medium to align the piezoelectric particles using the DEP process inside the molten matrix. The resulting distribution of aligned particles is frozen upon cooling the composite down to room temperature in as little as 10 min. A maximum piezoelectric voltage sensitivity (g₃₃) value of 54 ± 4 mV·m/N is reported for the composite with 10 vol% PZT, which is twice the value calculated for PZT based ceramics.

Highly flexible lead free composite film having random distribution of ceramic filler was synthesized using Barium Titanate (BT) as a filler and inexpensive Thermoplastic Polyurethane (TPU) as a matrix. The results show that the 30 vol% BT-TPU composite has a dielectric constant of ~31 which is comparable to the expensive and difficult to produce PVDF based composites. With a breakdown field of 150 kV/mm, an energy density value of ~3 J/cm³ was estimated. These lead-free TPU based composites provide an alternative to PVDF based composites for energy storage applications.

Piezoelectric composites made from soft and hard lead zirconium titanate (PZT) particles as filler and an epoxy as the matrix were prepared by dielectrophoresis and studied for their piezoelectric properties. It was found that the dielectric constant of the piezoelectric filler plays a significant role in determining the final piezoelectric properties of the composites. Composites with lower dielectric constant for the PZT filler material showed better piezoelectric properties compared to the composites with high dielectric constant filler. This can be ascribed to a more efficient poling of the piezoelectric filler particles. The aging behaviour of these composites was compared to that reported for monolithic ceramics.

A Ca₅Ni₄(VO₄)₆ low loss microwave dielectric ceramic with A site deficient garnet structure was prepared via the conventional solid state reaction method. Ca₅Ni₄(VO₄)₆ sintered at 980°C for 4h to a relative density of 96.2% exhibits favorable microwave dielectric properties such as a permittivity of 10.9, a Q×f value of 96,500GHz, and a τ _f value of -63.6ppm/°C. Its large negative τ _f could be compensated by forming a solid solution with LiCa₂Mg₂V₃O₁₂, that led to improved properties with a near-zero τ _f =-3.7ppm/°C, ε _r =10.2, Q×f=59,300GHz for 0.8Ca₅Ni₄(VO₄)₆-0.2LiCa₂Mg₂V₃O₁₂ after sintering at 955°C for 4h. Further on, 0.8Ca₅Ni₄(VO₄)₆-0.2LiCa₂Mg₂V₃O₁₂ proved to be chemically compatible with Ag electrodes, so it might be a possible candidate for LTCC applications.

A Li₄WO₅ ceramic with rock salt structure was prepared by the solid-state reaction method and its microwave dielectric properties was demonstrated for the first time. It could be well densified at relatively low sintering temperature (~890°C). XRD and DTA analysis revealed a phase transformation from cubic to orthorhombic occured at 700°C. Excellent microwave dielectric properties with a near-zero temperature coefficient of resonant frequency ~-2.6ppm/°C, a relative permittivity ~8.6 and a quality factor ~23,100GHz (at 11.0GHz) was obtained. Li₄WO₅ was found to be chemically compatible with silver powders when sintered at 890°C. All the results indicate that the Li₄WO₅ ceramic is a promising candidate as a base material in low temperature cofired ceramic technology.