Two-step flash sintering of (Mg1/3Ta2/3)0.01Ti0.99O2 giant dielectric ceramics

Purpose The purpose of this paper on the one hand is to reduce the sintering temperature, shorten the sintering time and improve the electrical properties of the sample through the two-step flash sintering method and on the other hand is to study the effect of electric field on the phase structure, microstructure and electrical properties of the flash sintering sample. Design/methodology/approach In this paper, (Mg1/3Ta2/3)0.01Ti0.99O2 giant dielectric ceramics were prepared by conventional sintering and two-step flash sintering, respectively. Further, the effect of electric field (600–750 V/cm) on the electrical properties of (Mg1/3Ta2/3)0.01Ti0.99O2 giant dielectric ceramics was studied. Findings The results show that compared with the conventional sintering, the sintering temperature of the two-step flash sintering can be reduced by 200°C and the sintering time can be shortened by 12 times. All sintered samples were single rutile TiO2 structure. Compared with conventional sintering, two-step flash sintering samples have finer grain size. The two-step flash sintered sample has similar dielectric properties to the conventional sintered sample. The dielectric constant of flash sintered samples decreases with the increase of electric field. When the electric field is 700 V/cm, the ceramic sample has the optimal dielectric properties, where the dielectric constant is approximately 5.5 × 103 and the dielectric loss is about 0.18 at 1 kHz. Impedance spectroscopy analysis shows that the excellent dielectric properties are attributed to the internal barrier layer capacitance model. Originality/value This paper not only provides a new method for the preparation of co-doped TiO2 giant dielectric ceramics but also has great potential in greatly improving efficiency and saving energy.