Methods for electropolishing and coating aluminum on air and/or moisture sensitive substrates

A method for electropolishing a surface of an air and/or moisture sensitive substrate, the method comprising:

• in a vessel, submerging the substrate in a first molten salt bath at a first temperature and applying an anodic current to the substrate to electropolish the surface of the substrate;
• wherein the first molten salt bath comprises a first inorganic salt bath;
• wherein, when used, the first inorganic salt bath comprises aluminum halide and alkali metal halide;
• and wherein, when used, the first inorganic salt bath comprises 82 wt % AlCl3, 11 wt % NaCl, and 7 wt % KCl;
• and
• wherein the anodic current density is 10-30 mA/cm2 applied using one of a reverse bias from a power supply coupled to the first molten salt bath and by swapping working and auxiliary electrode leads coupled to the first molten salt bath.

A method for coating aluminum on a surface of an air and/or moisture sensitive substrate, the method comprising:

• in a vessel, submerging the substrate in a molten salt bath with a temperature of 95 degrees C. to 250 degrees C., wherein the molten salt bath comprises an inorganic salt bath comprising 76-100 wt % AlI3, 0-15 wt % NaI, and 0-9 wt % KI;
• applying an anodic current to the substrate to electropolish the surface of the substrate;
• and
• coating the electropolished surface of the substrate with aluminum by one of submerging the substrate in a molten pool of aluminum, discontinuing the anodic current and allowing the electropolished substrate to dwell in the molten salt bath at a temperature of 95 degrees C. to 250 degrees C. such that the electropolished surface of the substrate is electrolessly coated with aluminum, and applying a reducing current to the electropolished substrate to electroplate the surface of the electropolished substrate with aluminum derived from the molten salt bath, wherein the reducing current is no more than 7 mA/cm2;
• wherein the molten salt bath comprises aluminum halide and alkali metal halide.