Electrolytic production of NF{sub}3 with a LiNiO{sub}2 coated nickel sheet anode prepared by atmospheric plasma spraying technique

摘要

A nickel sheet coated with LiNiO{sub}2 powder having average particle sizes of 40 and 50 μm in diameter by atmospheric plasma spraying technique was employed as the anode for electrolytic production of NF{sub}3. In electrolysis of a molten NH{sub}4F·2HF at 100℃ and 25 mA cm{sup}(-2), the anode gas generated at the LiNiO{sub}2 coated Ni sheet anode was composed of N{sub}2, O{sub}2, NF{sub}3, N{sub}2F{sub}2, N{sub}2F{sub}4, and N{sub}20, and its composition was almost the same as that at the Ni sheet anode. The current efficiency for the NF{sub}3 formation on the LiNiO{sub}2 coated Ni sheet anode was increased to reach the constant value of ca. 55% during electrolysis for 100 h, and it was almost the same as that on the Ni sheet anode. The anode consumption of the LiNiO{sub}2 coated Ni sheet was small compared with that of the Ni sheet. Also, the oxygen content in the oxidized layer formed on the LiNiO{sub}2 coated Ni sheet anode was high compared with that on the Ni sheet anode, and the surface of the LiNiO{sub}2 coated Ni sheet anode was covered with a compact and adhesive film having some defects. Although the bottom of the hollow was covered with a thinner layer, no pore penetrated through the oxidized layer. Hence, the LiNiO{sub}2 coated Ni sheet anode is favorable for the electrolytic production of NF{sub}3, and the oxidized layer on the LiNiO{sub}2 coated Ni sheet anode has the higher resistance to corrosion, because of the compact and adhesive film containing the higher content of oxygen formed on the anode.