Inert anode composed of Ni–Cr alloy substrate, intermediate oxide film and α-Al2O3/Au (Au–Pt, Au–Pd, Au–Rh) surface composite coating for aluminium electrolysis

An inert anode composed of alloy substrate, intermediate oxide film and surface composite coating for aluminium electrolysis has been fabricated. The intermediate oxide film (ZrO2/Y2O3) provides good adhesion and mutual diffusion resistance between the substrate and the surface coating which consists of α-Al2O3 particles embedded in Au (Au–Pt, Au–Pd, Au–Rh) matrix. The results of electrolysis test revealed that aluminium with high purity (>99.999%) can be produced. It is demonstrated that the inert anode exhibits superior erosion and corrosion resistance during aluminium electrolysis, especially in low-temperature (800 °C) electrolytes.

Research highlights
► Inert anode consists of alloy substrate, intermediate film and surface coating.
► Surface composite coating exhibits excellent erosion and corrosion resistance.
► Intermediate oxide film provides good adhesion and mutual diffusion resistance.
► High purity aluminium (>99.999%) is produced in low-temperature electrolysis.
► The cost of noble metals and the corrosion rate of the inert anode are both low.