Energy-efficient PEO process of aluminium alloys

The influence of pre-anodising in sulphuric and phosphoric acids on energy efficiency of voltage-controlled PEO process of three commercial wrought and cast aluminium alloys (AA1050, AA6082 and A356) has been investigated. The precursor anodic porous films enable up to 57% energy savings during PEO and produce ~35-40% increase of the coating microhardness compared with direct PEO. Total specific energy consumption values of 2.5-2.7 kW h m−2 µm−1 and 3.1-3.8 kW h m−2 µm−1 were achieved using phosphoric and sulphuric acid-formed precursors, respectively.