Effect of electric field on the sintering of ceria

As one of the alternative to conventional sintering, the application of electrical fields during sintering has aroused interest since decades, aiming at reducing the sintering time as well as improving the targeted material properties. Field assisted sintering (FAST) has undergone rapid development in the last years, as it provides a platform for manufacturing materials which are difficult or even impossible to be produced by conventional sintering [1]. More recently, strong focus is put on ‘flash sintering’ in the academia, where the densification completes within seconds [2]. However, the governing principles behind the field assisted sintering are still unveiled. In this work, the sintering of yttria-doped ceria samples (10 mol % yttrium doped ceria, 10YDC,and 0.1 mol % yttrium doped ceria, 01YDC) was studied under alternating electrical fields with a frequency of 50 Hz and field strengths significantly weaker than those required for the ‘flash regime’. For the first time, the dependence of sintering parameters on the applied electrical fields was investigatedwith constant sample temperatures, which was ensured by direct temperature measurement inside the sample and by thermo-electric finite element simulations. This excluded the macroscopic Joule heating and allowed to investigate the occurring mechanisms. In addition, the symmetric behavior under compressive and tensile loading could be experimentally verified for the first time. This part of study was done during a research stay in National Institute for Materials Science (NIMS), Japan. [...