Preparation of a Nickel-Nickel Oxide Composite by Hot Isostatic Pressing and Its Application for Anodes Used in Electrolytic Production of Nitrogen Trifluoride

Abstract

The nickel-nickel oxide composites prepared from a mixture of Ni and or NiO powders at 900°C under 2000 atm for 2 h by hot isostatic pressing were employed as the anode for electrolytic production of In electrolysis of a molten with and without LiF at 100°C and at 25 mA/cm2, the anode gas generated at the composite anode was composed of and and its composition was almost the same as that at the Ni sheet anode. The current efficiency for formation on the Ni-NiO composite anode from mixture of NiO and Ni powders was high compared with that on the composite anode from the mixture of and Ni powders. The best current efficiency for formation was ca. 53% on the Ni 5 mol % NiO composite anode, and it was almost the same as that of the Ni sheet anode. The addition of LiF in a molten increased it, presumably because of deposition of on the anode. On the other hand, the anode consumption of the Ni-NiO composite was much smaller compared with that of the Ni sheet electrode. Also, the oxygen content in the oxidized layer formed on the Ni-NiO composite anode was high compared with that on the Ni sheet anode. The scanning electron microscope observation revealed that the surface of the Ni-NiO composite anode was covered with the compact film having some defects. From these results, it is concluded that the Ni-NiO composite anode is favorable for electrolytic production of and that the oxidized layer on the anode has a high resistance to corrosion, because of the compact film containing a higher content of oxygen formed on the anode. © 2003 The Electrochemical Society. All rights reserved.