Naslov
Homogenization of the thermo-elastic properties of pristine and aged Ni-YSZ samples

Autori
Vešović, Toni ; Nakajo, Arata ; Greco, Fabio ; Burdet, Pierre ; Van Herle, Jan ; Barbir, Frano

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings 12th European SOFC and SOE Forum, EFCF 2016 / - Lausanne : European Fuel Cell Forum, 2016, A0913-A0913

Skup
12th European SOFC and SOE Forum, EFCF 2016

Mjesto i datum
Luzern, Švicarska, 05.07.2016. - 08.07.2016

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Thermo-elastic properties, Young modulus, aging, homogenization

Sažetak
Solid oxide fuel cell (SOFC) materials are exposed to varying types of mechanical loads and degradation processes during operation and the malfunction of a single cell can cause the end of service of the whole stack. The knowledge of the mechanical properties of the materials is essential to predict the lifetime of the SOFC stack. Several of the thin SOFC layers are heterogeneous materials. The measurement of their properties by mechanical testing is challenging. Methods based on 3-D imaging and computational homogenization are of interest to overcome these difficulties. This study is focused on the evolution of the thermo-elastic properties of nickel-yttria stabilized zirconia (Ni-YSZ) electrode upon SOFC operation. Focused ion beam-scanning electron microscopy (FIB-SEM) serial sectioning has been performed to obtain 3-D reconstructions of the anode material in the pristine state and after short stack operation for 4700 h. The coefficient of thermal expansion (CTE) and elastic constants have been computed using homogenization. The analysis started with the validation of the developed image processing and numerical procedure. A grid and volume independence study have been first performed to estimate the spatial resolution and minimum volume required for characterizing the investigated Ni-YSZ material. The computed thermo-elastic properties have been then compared to measurements of the pristine anode from dilatometry and four-point bending tests. After these validation steps, the changes in the properties caused by operation have been characterized and the relationship with the evolution of the metric and topological properties discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemijsko inženjerstvo, Strojarstvo

POVEZANOST RADA