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.
Effects of Ball Milling Processing Conditions and Alloy Components on the Synthesis of Cu-Nb and Cu-Mo Alloys