抄録
The anodic coatings on aluminum in 5wt% oxalic acid solution were investigated by pulse current with a negative current component, including the effects of such variables as temperature, voltage and negative current density.
It was found that thick coatings could not be obtained under conditions of increasing negative current, thick coatings could only be obtained by controling negative current. The hardness of the coatings increased with decreasing temperature and anodizing time, and with increasing current density. Coatings with a hardness of more than Hv 600 were obtained when anodizing conditions were of 10°C, 4A/dm2 were maintained for 30min. In coatings formed by pulse current with a negative current component, cell size was uniform, and the pores were divided into branches.
