Patent ID: 8586196

Claim:
An aluminum plating film formed by electroplating using a plating bath which is constituted by alkylsulfone as a solvent and an anhydrous aluminum trichloride (III) (AlCl 3 ) as a solute, with a micro-Vickers hardness of 250 or higher, wherein oxygen, carbon, sulfur and chlorine are contained as impurities, with an oxygen concentration of greater than or equal to 1.2 wt. % and less than or equal to 3.0 wt. %, a carbon concentration of greater than or equal to 0.35 wt. % and less than or equal to 0.8 wt. %, a sulfur concentration of greater than or equal to 0.20 wt. % and less than or equal to 1.0 wt. %, a chlorine concentration of greater than or equal to 0.15 wt. % and less than or equal to 1.0 wt. %, and a mean sulfur composition in the aluminum plating film is 1.35 times±30% of a chlorine composition, on a basis of a ratio of atomic concentrations, in the aluminum plating film, wherein aluminum is the balance so that an aluminum concentration is 98 wt. % or lower, and a total concentration of the impurities is 2 wt. % or higher, and wherein the weight percentages are determined with respect to the total amounts of oxygen, carbon, sulfur, chlorine, and aluminum in the aluminum plating film.