Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y, X.sub.y)SO.sub.2CX.sub.3, where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y, X.sub.y)SO.sub.2CX.sub.3), and (d) AlF.sub.3-organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm.sup.2.

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y, X.sub.y)SO.sub.2CX.sub.3, where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y, X.sub.y)SO.sub.2CX.sub.3), and (d) AlF.sub.3-organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm.sup.2.

A tungsten wire according to an embodiment is a tungsten wire made of a W alloy containing rhenium, and includes a mixture on at least a part of a surface thereof, the mixture contains W, C, and O as constituent elements, and taking a radial cross-sectional thickness of the mixture as A mm and a diameter of the tungsten wire as B mm, an average value of a ratio A/B of A to B is 0.3% to 0.8%.

A tungsten wire according to an embodiment is a tungsten wire made of a W alloy containing rhenium, and includes a mixture on at least a part of a surface thereof, the mixture contains W, C, and O as constituent elements, and taking a radial cross-sectional thickness of the mixture as A mm and a diameter of the tungsten wire as B mm, an average value of a ratio A/B of A to B is 0.3% to 0.8%.

A method of manufacturing a waveguide device including the following steps: additive manufacturing of a core provided with an opening; additive manufacturing of at least a portion of an anode through the opening; immersion of the core in a metal ion bath; and electrodeposition of a conductive metal layer on the walls of the opening, by applying an electric current between the anode and a cathode.

A method of manufacturing a waveguide device including the following steps: additive manufacturing of a core provided with an opening; additive manufacturing of at least a portion of an anode through the opening; immersion of the core in a metal ion bath; and electrodeposition of a conductive metal layer on the walls of the opening, by applying an electric current between the anode and a cathode.

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y,X.sub.y)SO.sub.2CX.sub.3, where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y,X.sub.y)SO.sub.2CX.sub.3), and (d) AlF.sub.3-organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm.sup.2.

Methods for electropolishing and coating aluminum on a surface of an air and/or moisture sensitive substrate, including: in a vessel, submerging the substrate in a first molten salt bath and applying an anodizing current to the substrate at a first temperature to electropolish the surface of the substrate; wherein the first molten salt bath includes one of a first organic salt bath and first inorganic salt bath; wherein, when used, the first organic salt bath includes one of (a) aluminum halide and ionic liquid, (b) a combination of an aluminum halide and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y,X.sub.y)SO.sub.2CX.sub.3, where y is a number from 0-5), (c) a combination of an aluminum halide, an ionic liquid, and halogenatedmethylphenylsulfone (C.sub.6(H.sub.5-y,X.sub.y)SO.sub.2CX.sub.3), and (d) AlF.sub.3-organofluoride-hydrofluoric acid adduct; wherein, when used, the first inorganic salt bath includes aluminum halide and alkali metal halide; and wherein the anodizing current is 10-30 mA/cm.sup.2.

An electrochemical method includes performing anodic halogenation of Cu foils, performing subsequent oxide-formation in a KHCO.sub.3 electrolyte, and performing an electroreduction in neutral KHCO.sub.3 to generate a copper catalyst.

An electrochemical method includes performing anodic halogenation of Cu foils, performing subsequent oxide-formation in a KHCO.sub.3 electrolyte, and performing an electroreduction in neutral KHCO.sub.3 to generate a copper catalyst.