Synthesis of laminated composites of alumina and nickel oxides by AC anodization and electrodeposition

Laminated composites of alumina and nickel oxide were fabricated by the oxidation of an aluminium sheet in an oxalic acid solution using alternating current (AC) and the electrodeposition of Ni2 +, respectively. Laminated alumina with 120 nm thick layers was first obtained by AC anodization. Subsequently, Ni2 + was deposited in the alumina interlayer by AC electrodeposition. During electrodeposition, Ni2 + moved into the laminated alumina, and nanoparticles were formed in the interlayers of each alumina layer, according to the results obtained from the SQUID and XRD measurements. The particles were confirmed to be NiO. The formation of NiO particles improved the mechanical properties, as measured by nanoindentation. In particular, the indentation hardness of the laminated composite film increased three times compared to the laminated alumina film.