Control of surface quality of sub-millimeter cylindrical gold targets

The morphology, composition and causes of defects are analyzed to reduce defects on the gold layer prepared by electrochemical deposition from sulfite solution, and to improve the surface quality of sub-millimeter cylindrical gold targets, by means of SEM and EDS. The effects of current density, metallic impurity, organic pollution, pre-deposition parameters and mandrel quality on the quality of the gold plating are discussed, along with their mechanisms. The result indicates that the current density must be controlled strictly. The optimal current density ranges from 2.4 to 3.2 mA/cm2 when the concentration of gold ranges from 13 to 22 g/L, and from 2.0 to 2.6 mA/cm2 when the concentration of gold ranges from 5 to 13 g/L. The parameters of predeposition must be optim