Numerical Simulation of Rapid-Heating-Enhanced Densification and Grain Growth during Electric Current Assisted Sintering of Oxide Ceramics

von Shufan Wang

157 Seiten, Taschenbuch

Kurzbeschreibung des Verlags

Electric current assisted sintering (ECAS) is a field-assisted powder consolidation technique that enables rapid densification through high heating rates and short processing times. It has attracted growing interest as an efficient route for processing advanced ceramics, but the mechanisms responsible for the enhanced densification are still under debate. This dissertation investigates the thermal and non-thermal (electric field) effects in ECAS by comparing two different sintering routes: flash sintering, in which the sample is heated directly by electric current passing through it, and ultrafast high-temperature sintering, in which the sample is heated indirectly through a conductive tool. The study focuses on two oxide ceramics: 8 mol.% Y₂O₃-stabilized ZrO₂ (8YSZ) and strontium titanate (SrTiO₃). By combining systematic experiments with numerical simulation, the dissertation clarifies the roles of thermal and non-thermal effects during rapid sintering. A central finding is that the ultra-high heating rate is the dominant factor responsible for the accelerated densification observed in both investigated material systems. In addition, the finite element method (FEM), combined with a newly developed constitutive model, was employed to predict temperature distribution, densification, and grain growth in the samples. Electrical polarity-induced microstructural asymmetry was observed in 8YSZ and successfully reproduced by modeling. For SrTiO₃, the modeling further shows how rapid heating affects pore evolution and thereby enhances densification. To describe this behavior, the Skorohod-Olevsky Viscous Sintering model was modified to account for pore-structure effects and validated against experimental results from both conventional sintering and ultrafast high-temperature sintering. Overall, this dissertation provides new insight into the underlying mechanisms of ECAS through modeling and contributes to the design and optimization of efficient fast-sintering routes for advanced oxide ceramics.

• Reihe: Werkstoffanwendungen im Maschinenbau
• Themen: Technologie, Ingenieurswissenschaft, Landwirtschaft, Industrieprozesse Maschinenbau und Werkstoffe
• ISBN: 9783819107788
• Sprache: Englisch
• Erscheinungsdatum: 07.08.2026
• Größe: 21 x 14.8 cm
• Verlag: Shaker