Microstructure and conductivity of blacklight‐sintered TiO₂, YSZ, and Li_0.33La_0.57TiO₃

Abstract

Rapid densification of ceramics has been realized and its merits were demonstrated through multiple approaches out of which UHS and flash sintering attract recent attention. So far, however, scalability remains difficult. A rise in throughput and scalability is enabled by the introduction of blacklight sintering powered by novel light source technology. Intense illumination with photon energy above the bandgap (blacklight) allows high absorption efficiency and, hence, very rapid, contactless heating for all ceramics. While heating the ceramic directly with light without any furnace promises scalability, it simultaneously offers highly accurate process control. For the technology transfer to industry, attainable material quality needs to be assured. Here, we demonstrate the excellent microstructure quality of blacklight-sintered ceramics observed with ultrahigh voltage electron microscopy revealing an option to tune nanoporosity. Moreover, we confirm that electronic, electron, oxygen, and lithium-ion conductivities are equal to conventionally sintered ceramics. This gives the prospect of transmitting the merits of rapid densification to the scale of industrial kilns.

A Perspective on Emerging and Future Sintering Technologies of Ceramic Materials

“…[95] Blacklight sintering is the latest invention in the field of photonic sintering. [96,97] This process uses blue wavelengths to maximize the optical absorption of the light in the ceramic powder for optimal heating. As light source, Xe flash lamps or blue lasers can be used.…”

“…The electric properties are in the range of those for conventional sintering. [97] Blacklight sintering turns out to be very versatile: very homogeneous microstructures can be achieved, but depending on the parameters and sample support, density gradients and surface textures are possible as well. While this process is naturally most efficient for planar geometries, it is a very flexible sintering process that allows a free design of heating schedule, atmosphere, and sample size.…”

Elektronenmikroskopische Untersuchung des Einflusses elektrischer Felder auf das Sinterverhalten von Oxidkeramiken

“…Eine deutliche Schrumpfung der ZnO-Grünkörperproben, die ohne Bindemittel hergestellt wurden, wurde sowohl während der Heizexperimente, als auch während der Heiz-/Strom-Experimente im TEM und SEM beobachtet, obwohl eine Veränderung der Kornstruktur nicht festgestellt wurde (Abbildung 4.6). Die relative Probendichte konnte nicht eindeutig bestimmt werden, sodass nicht klar ist, ob die Schrumpfung vorwiegend auf Materialverlust zurückzuführen ist oder auch den Verlust von Porosität einschließt, wie es für Sinterverfahren in Literaturstudien diskutiert wird [82,[318][319][320].…”