Thick and macroporous anodic alumina membranes for self-lubricating surface composites

The additive (including organic carboxylic acid and Ce salt) in the phosphate-base electrolyte plays an important role on the increase of film thickness. In this compound electrolyte, the pore diameter of the anodic alumina membranes is about 100 nm in average, pore density is 18 pores μm−2 and porosity 14%. The thickness can exceed 20 μm with appropriate anodizing time and temperature.