Considering the surface of aluminum alloy disk substrate is locally concentrated and symmetrical after chemical mechanical polishing（CMP） with tiny concave defects in range of 1～3 μm

scanning electron microscope（SEM）

focused ion beam microscope（FIB） and surface profile were utilized to analyze the microstructure and cross section of specimens. Combined with the production process of aluminum substrate and electroless nickel-plating process

the evolution of surface morphology in various processes as well as the mechanism was investigated. The results indicate that serious corrosion occurs around the intermetallic compound（IMC） area on the surface of the aluminum substrate during the cleaning process

due to the uneven concentration distribution of the detergent

whereas low-concentration inhibitor is highly corrosive

resulting in a large number of pits. After electroless nickel plating

concaves are generated on the pit location of the nickel layer

which can not be completely removed during the polishing process

and finally leads to pitting defects on the surface of the product. By adding the automatic overflow stirring device

the heterogeneous distribution of cleaning agent concentration is eliminated

effectively avoiding the abnormal uneven corrosion.