Structure and high-temperature oxidation behaviour of Cu-Ni-Fe alloys prepared by high-energy ball milling for application as inert anodes in aluminium electrolysis

摘要

Cu_xNi_(85-x)Fe_(15) (0≤ x≤85 wt.%) compounds were prepared by mechanical alloying. Monophased face centered cubic (fcc) Cu-Ni-Fe alloys were obtained after 10 h of milling for x varying from 0 to 50, whereas bi-phased compounds fee Cu-Ni-Fe + body centered cubic (bec) Fe were formed with richer-Cu compounds. Their oxidation kinetics in air at 750 ℃ is parabolic for all compositions and increases drastically for x>～30. A stable anode for aluminium electrolysis in low-temperature (700 ℃) KF-AlF_3 electrolyte was obtained for 65≤x≤ 85. However, a substantial increase of the Cu contamination in produced aluminium was observed for x > 70.