Porosity, microstructure and mechanical behavior of NiO–YSZ composite anode for solid oxide fuel cells

Abstract

In this study, NiO–yttria stabilized zirconia (YSZ) composite anodes were prepared by using ball-milling followed by a sintering process. For this purpose, two different weight percent ratios of NiO and YSZ powders (50 : 50 and 60 : 40) were mixed by the cost-effective ball-milling method. The morphology and particle size distribution of the mixed powders were investigated using scanning electron microscopy and dynamic light scattering methods, respectively. The powders were then uniaxially pressed to form pellets with a thickness and diameter of around 1 and 22 mm, respectively. Sintering of the pellets was conducted at 1 100 °C and the microstructure and porosity, as well as phase analysis of bulk composites, were then investigated using scanning electron microscopy and X-ray diffraction, respectively. More importantly, the microhardnesses of the prepared pellets were obtained and compared with literature values to evaluate the accuracy of the sintering process. The results showed that the open porosity of the samples varied between 30 to 40 percent, which makes them suitable for anode application in solid oxide fuel cells. The prepared NiO–YSZ composites with a uniform distribution of Ni particles showed a value of microhardness above 0.5 GPa, and these results were discussed in detail.

Fabrication of improved La0.8Sr0.2MnO3 cathode layer for solid oxide fuel cells using economical coating methods

“…A variety of forces were applied by automatic hydraulic press to have uniform and crack free substrates. Complete explanation of the composite substrates and their characterization was described elsewhere . The disks were fabricated by prepressing NiO‐YSZ; then YSZ powder was added on the prepressed disks and the multilayer powders were pressed at 657, 710, 763, 789, 815, and 842 MPa.…”

“…The porous NiO‐YSZ substrate and YSZ electrolyte were prepared by the uniaxial pressing method, using an automatic hydraulic press (Zwick/Roell, Ulm, Germany). The main substrate was prepressed by employing 250 MPa pressure and then the YSZ powder was added on top of it; 657‐842 MPa was applied to the powders to form them into the disks with the diameter and thickness of 22 mm and 1 mm, respectively.…”