Abstract

This work studies the densification of ceramic powders via ultrafast sintering, a technique that could optimize the fabrication of components for energy conversion systems, such as solid oxide fuel cells (SOFCs). Using citrate-nitrate synthesis combined with mechanical milling, samples with nominal composition LaSrAl0.95xMgxNa0.05O4-delta (x = 0.1 and 0.3) were synthesized. These powders were sintered within 1 min by ultrafast hightemperature sintering (UHS) at 1400 degrees C. The crystallographic characterization was carried out by X-ray diffraction with multiphase Rietveld refinement for volumetric quantification of impurities. The microstructure, analyzed by scanning electron microscopy, revealed high grain cohesion for an Mg content of x = 0.1 but low densification. The electrical properties were evaluated by impedance spectroscopy. We demonstrate that the ultrafast sintering process does not affect the functional properties of the solid oxide electrolyte. This is a highly advantageous result, as it shows that sintering time can be reduced from several hours to just 1 min while preserving comparable electrochemical performance, significantly improving the efficiency and sustainability of the fabrication process. The conductivity of the doped samples increased by three orders of magnitude, from 0.016 mS/m to 13.3 mS/m for Mg content x = 0.3, achieving a 99.84% reduction in sintering time. New strategies should be explored for microstructure improvement, impurity segregation, and densification.