磷酸电解液中铝阳极氧化过程中孔隙成核与重排动力学的控制OA

Anodic aluminium oxide(AAO)porous films with an interpore distance of several hundred nanometers are of great interest due to their unique interaction with visible and near-infrared light,and high thermal stability up to 1500 ℃.These porous films are prepared by aluminium anodizing at high voltages in weak acids,leading to a slow kinetics of initial stages of porous structure formation.Here,we propose an approach to accelerate AAO formation in electrolytes based on weak acids such as phosphoric acid.Aluminium foils,pre-patterned using first anodizing under different conditions and subse-quent selective dissolution of a sacrificial AAO layer,were utilized as substrates.The morphology of the aluminium surface,including surface roughness and height of pyramidal spikes,plays a crucial role in the pore nucleation and rearrangement process during the second anodizing.In particular,by first anodizing in strong acid electrolytes at low voltages(such as 0.3 mol·L-1 sulfuric acid at 25 V),it is possible to double the rate of pore nucleation and subsequent reach of the steady-state regime during second anodizing in phosphoric acid.As a result,about 2 hours can be saved during the two-step anodizing process in phosphoric acid if a strong acid electrolyte is used for the first anodizing to pre-pattern aluminium surface.