Our study aimed to comprehend how variations in flash sintering parameters affect the evolution of microstructure and electrical properties of yttria-stabilised zirconia. For this purpose, cylindrical samples were sintered via a classic flash method (voltage-current control), with controlled increase in the current ramp, employing thermal insulation, and combining current ramp control with thermal insulation. The results demonstrated that the combination of current ramp control and thermal insulation yielded higher densification compared to other variations. Microstructural analysis revealed finer grain sizes and lower grain-boundary tensions on employing current ramp control, particularly when combined with thermal insulation. For all flash-sintering methods, greater electrical conductivity of grain boundaries was observed compared to conventional sintering, suggesting an enhancement in ionic conduction. This study underscores the potential of customised FS techniques in optimising sintering processes and enhancing material properties. © 2024 Elsevier Ltd

This work was supported by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001, the Sao Paulo Research Foundation (FAPESP) [2015/07319-8 and 2019/14677-9] . We also acknowledge financial support from the project PID2021-123308OB-I00, funded by MCIN/AEI/10.13039/501100011033 and "ERDF A way of making Europe" by the European Union.

Peer reviewed