Synthesis and Pressure-Assisted Sintering of CaCu3Ti4O12 Dielectrics

Abstract

In this paper, we examined the dielectric properties of CaCu3Ti4O12 (CCTO) ceramics fabricated by various routes and discussed the most important conditions affecting their dielectric behavior. We prepared feedstock powder using a molten salt route and compared it with a commercial powder. Both powders were sintered using SPS. For some samples, annealing was applied after sintering. Other samples were obtained by high-pressure forming and conventional sintering, using both powders. Phase composition, porosity and microhardness were evaluated in comparison with the literature. The results showed that a sintering temperature just below or equal to 1000 °C should be set for the SPS process. However, the best dielectric characteristics were obtained in samples prepared by high-pressure forming and conventional sintering, which showed a relative permittivity of 22,000 and a loss tangent of 0.13 at 1 MHz.

Characterization of LaFeO3 Dielectric Ceramics Produced by Spark Plasma Sintering

“…And, finally, the relaxation of permittivity was the governing factor at high frequencies, like in all high-permittivity materials. However, similarly to CCTO ceramics [21], the LFO application prospective would mainly involve a material preserving its colossal permittivity up to at least 50 kHz, which is not the case of actual SPS-processed LFO.…”

Dielectric Properties of Compacts Sintered after High-Pressure Forming of Lithium Fluoride

“…With a motivation to produce high-quality LiF dielectrics, we applied high-pressure forming (HPF) [7] before conventional sintering. This approach enabled us to avoid the addition of a plasticizer before the green body formation.…”