A method of manufacturing a nano-structured aluminum oxide film. The first step involves degreasing an aluminum plate using a degreasing solution. The next step involves electropolishing the aluminum plate after degreasing with an electropolishing solution that is free of perchloric acid and chromic acid. The next step involves pre-anodizing the aluminum plate after electropolishing with an anodization acid solution for a first predetermined time period. The next step involves anodizing the aluminum plate after electropolishing with the anodization acid solution for a second predetermined time period to form an anodized membrane on the aluminum plate. The next step involves separating the anodized membrane from the aluminum plate with a solution free of chrome. The last step involves cleaning the anodized membrane.

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.

The present invention is directed to a chromatic effect light reflective unit (1; 1a-1g). The unit (1; 1a-1g) comprises a reflective layer (10) having at least one reflective surface (11), and a chromatic diffusion layer (20) having a first surface (21) proximal to the reflective surface (11) and a second surface (23), opposite and substantially parallel to the first, configured to be illuminated by incident light, wherein the chromatic diffusion layer (20) comprises a nano-pillar (70) or nano-pore (30) structure in a first material having a first refractive index (n1), immersed in a second material having a second refractive index (n2) other than the first (n1), in which the first and second materials are substantially non-absorbing or transparent to electromagnetic radiations with wavelength included in the visible spectrum, wherein the ratio (n.sub.M/n.sub.m) between a higher refractive index (n.sub.M) and a lower refractive index (n.sub.M) chosen between the first (n1) and the second (n2) refractive indexes is comprised between 1.05 and 3, wherein the nano- pillars (71) or nano-pores (31) have a development along a main direction not parallel to the first surface (21) and the second surface (23) of the chromatic diffusion layer and the nano- pillars (70) or nano-pores (30) structure is characterized by a plurality of geometric parameters comprising a pillar diameter or pore diameter (d.sub.p), a pillar length or pore length (1.sub.p) along said main development direction, and a surface density of nano-pillars or nano-pores (D.sub.p) and/or a structure (30,70) porosity (P.sub.p) and wherein the pillar diameter or pore diameter (d.sub.p) is comprised between 40 nm and 300 nm, the length (l.sub.p) along the main development direction is comprised between 300 nm and 40 .Math.m (300 nm < l.sub.p < 40 .Math.m) and at least one between the surface density of nano-pillars or nano-pores (D.sub.p) and the structure (30,70) porosity (P.sub.p) is configured to provide a higher regular reflectance for wavelengths of incident light comprised in the range of red with respect to wavelengths of incident light comprised in the range of blue and a higher diffuse reflectance for wavelengths of incident light comprised in the range of blue than wavelengths of incident light comprised in the range of red.

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.

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.

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.5y,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.5y,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.5y,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.5y,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.