No abstract

The synthesis of the nickel oxide-gadolinium doped ceria (NiO-GDC with 65:35 wt.%) nanocomposite powders with a stoichiometry of Gd0.1Ce0.9O1.95 was performed via fast solution combustion technique; using three different mixing methods: (i) CM (metal cations in an aqueous solution), (ii) HM (hand mortar), and (iii) BM (ball milling). The nanocomposite powders were calcined at 700 °C for 2 h and characterized by Transmission Electron Microscopy (TEM), X-ray fluorescence (XRF), and X-ray Diffraction XRD. The TEM and XRD analyses evidenced the well-dispersed NiO and GDC crystallites with the absence of secondary phases, respectively. Later, the calcined powders (NiO-GDC nanocomposites) were compacted and sintered at 1500 °C for 2 h. The microhardness of the sintered nanocomposites varies in accordance with the synthesis approach: a higher microhardness of 6.04 GPa was obtained for nanocomposites synthesized through CM, while 5.94 and 5.41 GPa were obtained for ball-milling and hand-mortar approach, respectively. Furthermore, it was observed that regardless of the long time-consuming ball-milling process with respect to the hand mortar, there was no significant improvement in the electrical properties.

By this work, the viability of the spray coating as a cost‐effective and reliable technique for the coating of Ce0.9Gd0.1O1.95 (GDC) electrolyte layer on the mini‐tubular NiO–GDC anodes based a solid oxide fuel cell (SOFC) fabrication was assessed. The compatibility of the anode and electrolyte was analyzed by using XRD. The variation in thickness and morphology of the electrolyte film as a function of the coating cycles was discussed with optical and scanning electron microscopes. By similar formulation, the coating of La0.6Sr0.4Fe0.8Co0.2O3 –Ce0.9Gd0.1O2–δ (LSCF–GDC) was performed to achieve porous cathode. An individual micro‐tubular anode supported cell with configuration NiO–GDC/GDC/LSCF–GDC as anode/electrolyte/cathode was tested in the SOFC mode with humidified hydrogen as fuel and stationary air as oxidant. The fabricated mini‐SOFC prototype that generated a maximum power density of 0.510 W/cm2 at 600°C signifies the potential of this industrially scalable low‐cost coating technique.

Two contrasting feeds in terms of copper recovery from a Cu (Mo) porphyry deposit but with similar overall mineralogy have been characterized by X-ray diffraction for their <1 µm fraction illite crystallinity, Scherrer width and by atomic force microscopy for surface roughness. The unfavorable feed displayed slightly higher crystallinity, larger Scherrer width and surface roughness factors, than the feed with good Cu recovery. As Scherrer width is an easy and cheaply to determine parameter it is suggested as complementary information to particle size distribution analyses when dealing with feeds where illite may affect pulp viscosity or gangue adhesion to bubbles during flotation.