Tailoring the microstructure by a proper electric current control in flash sintering: The case of barium titanate

Particle size effect on the microstructure and the aging process of flash-sintered barium titanate from micro and nanopowders

“…9 In a previous work, we found that a homogeneous microstructure is obtained for flash-sintered BTO from micropowder and that the main electrical parameter affecting grain growth is the electric current, while the electric field does not seem to have a discernible effect. 17 This result is replicated in this experiment and recorded in Fig. 1f–h.…”

“…It has been demonstrated that applying a slow current ramp during the incubation stage helps achieve better densification and microstructure homogeneity, although there is no consensus on the microscopic origin of these enhancements. 3,30–33 In a previous work, 17 the influence of the current density profile during flash sintering over the microstructure and functional properties of BTO obtained from micropowder was widely discussed. It was reported that improved densification and enhanced functional properties were observed for initially low electric current slopes and current rates, which hints that defect dynamics play an important role during flash sintering.…”

“…15,16 Both undoped and doped BTO were recently proven to be achievable via flash sintering, 9,10 and fine microstructure tuning has been proven to be obtained by a proper electric current control. 17…”

Flash and Breakdown: Thermal Runaway and Dielectric Breakdown as Competing Mechanisms During Flash Sintering of Barium Titanate

“…In the case of barium titanate, the initial study utilizing conventional flash sintering has already reached a high density of the samples, while a recent study utilizing the novel controlled current ramping method has achieved great homogeneity and grain-size control. [9,11] These results are in strong contrast to studies conducted on shorter samples with a bigger cross-section (5 Â 5 mm) reporting far lower densities and damage to the samples and concluding that conventional flash sintering should be avoided for barium titanate. [8,12] In a previous study, we investigated samples of different sizes using in situ infrared imaging and observed a strong decrease in temperature differences for thinner samples.…”