Search

This work examines the impact of sintering thermal history on kinetics of grain growth for 1264 ppm (0.1 wt%) MgO‐doped alumina. Results suggest that sintering with a high heating rate in the order of ∼103°C min−1 retards grain growth rate. By contrast, a slow heating rate of 5°C min−1 resulted in an increase in grain growth constant by a factor of ∼4. The segregation of Mg to grain boundaries, favored by short sintering duration, is considered to be one of the possible factors contributing to the retarded grain growth rate for the rapidly heated compacts. Furthermore, it is proposed that the simultaneous combination of retarded grain boundary migration rate and limited surface‐diffusion‐driven grain coarsening, promoted by rapid heating, enables pressure‐less fabrication of translucent alumina without a need for vacuum or hydrogen atmosphere. In fact, it is demonstrated that weakly translucent alumina can be produced at relatively low temperatures of 1475–1550°C by sintering with a high heating rate (herein, ∼103°C min−1) in ambient atmosphere. [ABSTRACT FROM AUTHOR]

Lithium aluminum germanium phosphate solid electrolyte is a promising candidate for all‐solid‐state batteries. The currently available processing techniques based on melting‐quenching require a rather lengthy crystallization step lasting up to 8 hours. In this work, the newly emerged ultra‐fast high‐temperature sintering (UHS) was proposed to achieve in a single step reactive consolidation of powder mixture (GeO2, Al(PO3)3, LiPO3) and crystallization of the electrolyte within 16 minutes. Samples produced using UHS had a better phase purity, reduced Li loss, and improved ionic conductivity when compared to the counterparts prepared using conventional crystallization at 850°C for 6 h. In fact, specimens prepared by UHS achieved a crystallinity of 90% and ionic conductivity as high as 1.31 × 10−4 S cm−1. [ABSTRACT FROM AUTHOR]

Water‐Assisted cold isostatic Pressing (WAP) enabled pressure‐less sintering of fine grained (0.6 μm) and nearly full dense (99.3%) weakly translucent alumina ceramics. As a term of comparison, Dry Pressed (DP) samples, prepared under identical processing conditions, maintained an opaque appearance, and their relative density did not exceed 97.7%. The enhanced compaction of WAP allowed to lower the sintering temperature down to 1350°C, which is approximately 100–150°C lower than that of DP powder. WAP samples resulted in an apparent activation energy for sintering (640 kJ/mol) matching literature values, confirming that the enhanced sinterability was attributed to an improved green density rather than a change in sintering mechanisms. [ABSTRACT FROM AUTHOR]

We report on a novel consolidation technique based on the combination of a liquid (cold sintering) and electricity (flash sintering). The evolution of hydrogen from electrolysis of the solvent triggered the Flash Cold Sintering (FCS) event without need for external heating. Electrochemical effects became pronounced in the presence of acetic acid solution as the electrolyte had an increased conductivity compared to pure water. By adjusting the acetic acid molar concentration to 0.5 M and by inverting the polarity during FCS a 5 mm diameter 0.8 mm thick Nb2O5 sample was evenly sintered up to 99% in 100 s at a temperature as low as 350°C. Conventional sintered counterparts achieved a 95% relative density when dwelled for 240 min at 1400°C. The inherent complexity of the proposed FCS approach resulted in enhanced densification and weakly translucent samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] Powders of Mo and Si according to MoSi2 stoichiometry were mechanically alloyed. [•] The as milled powder mixture was sintered using spark plasma sintering. [•] We investigated the microstructure and mechanical properties of samples. [ABSTRACT FROM AUTHOR]