Patent Publication Number: US-2009225427-A1

Title: Optically modified three-dimensional object

Description:
FIELD OF THE INVENTION 
     The invention relates to optical coatings for three-dimensional objects. 
     BACKGROUND OF THE INVENTION 
     Optical coatings are known in the art and may be used on various substrates. For example, optical coatings may be used on glass or semiconductor substrates to create photonic band gap materials that may be used for telecommunication systems at specific electromagnetic wavelengths. Similarly, optical coatings for multilayer dielectric mirrors positioned on a glass substrate may be used to create mirror structures having high reflectivity at various wavelengths. 
     These optical components may be created by depositing optical layers using various procedures including chemical vapor deposition, physical vapor deposition, metal organic chemical vapor deposition, arc vapor deposition, and other procedures. These processes are designed to typically apply layers on a flat substrate. The processes do not lend themselves to application on a three-dimensional object such that a thin coating may be uniformly and accurately positioned on the entire surface of the three-dimensional object. There is therefore a need in the art for an optical coating that may be applied to a three-dimensional object to optically modify the three-dimensional object. Additionally, there is a need in the art for an optically modified three-dimensional object that has a metal substrate such that a coating may be applied to the three-dimensional object such that a visual property of the substrate material in combination with a visible light spectrum can be modified to create a desired visual appearance. 
     Various three-dimensional objects may have applied thereon a surface coating of a decorative material to enhance the visual appearance of the object. One such coating known in the art is a chrome coating that may be applied to a metal surface to create an aesthetically pleasing appearance. Chrome is typically electroplated onto a metal surface using a hexavalent chromium electroplating bath. There are environmental and health and safety reasons to minimize or eliminate the use of hexavalent chromium which is a known carcinogen. Additionally, various social policies and concerns are in place to lower the amount of chromium used to produce various consumer goods. Therefore, there is a need in the art for an optically modified three-dimensional object that mimics the appearance of a highly reflective chromium surface without the use of hexavalent chromium during the manufacturing process. There is also a need in the art for creating decorative finishes on a three dimensional object using an optically modifying coating. 
     SUMMARY OF THE INVENTION 
     In one aspect, there is disclosed an optically modified three-dimensional object that includes a metal substrate material. At least one dielectric material is on the metal substrate material. A visual property of the substrate material and visible light reflected by the at least one dielectric material create a desired visual appearance of the three-dimensional object. 
     In another aspect, there is disclosed an optically modified three-dimensional object that includes a metal substrate material. At least one dielectric material is on the metal substrate material. The three-dimensional object has a chrome-like appearance without the use of chromium. 
     In another aspect, an optically modified three-dimensional object includes a metal substrate material. A plurality of alternating layers of low and high refractive index materials is on the metal substrate material. A visual property of the substrate material and visible light reflected by the plurality of alternating layers of low and high refractive index materials creates a desired visual appearance of the three-dimensional object. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a graphical depiction of a portion of a three-dimensional object detailing the substrate and the at least one dielectric material; 
         FIG. 2  is a graphical depiction of a portion of a three-dimensional object detailing the substrate and alternating layers of high and low refractive index; 
         FIG. 3  is a graphical depiction of a portion of a three-dimensional object detailing substrate, a protective layer and alternating layers of high and low refractive index; 
         FIG. 4  is a graphical depiction of a portion of a three-dimensional object detailing the substrate, alternating layers of high and low refractive index and a top layer of zirconium oxide; 
         FIG. 5  is a graphical depiction of a portion of a three-dimensional object detailing the substrate, a protective layer, alternating layers of high and low refractive index, and a top layer of zirconium oxide; 
         FIG. 6  is a plot of the reflectance versus wavelength at 7° of angle of incidence before and after deposition for an embodiment detailed in Example 1; 
         FIG. 7  is a TEM cross-sectional image of a sample of the embodiment of  FIG. 6 ; 
         FIG. 8  is a plot of the reflectance versus wavelength at various angles of incidence before and after deposition for an embodiment detailed in Example 2. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the figures, there are shown portions of an optically modified three-dimensional object  5  that includes a metal substrate material  10 . At least one dielectric material  15  is on the metal substrate material  10 . The visual property of the substrate material  10  and visible light reflected by the at least one dielectric material  15  create a desired visual appearance of the three-dimensional object  5 . The combination of the metal substrate material  10  and at least one dielectric material  15  creates an optical interference coating  20  that may be used to create a desired color appearance on the surface of the three-dimensional object  5 . Manipulating the reflectance of light in the visible range to which the human eye is sensitive allows for various desired reflective colors to be viewed on a surface of the optically modified three-dimensional object  5 . In one aspect, the optical interference coating  20  may provide a color-correcting property to mimic other metals and create specific color appearances. The optical interference coating  20  is a combination of the color of the underlying substrate material  10  and the reflected visible light coming off the surface of the at least one dielectric material  15  applied to the three-dimensional object  5 . 
     In one aspect, the at least one dielectric material  15  may include a plurality of alternating layers  25  of high and low refractive index materials defining a dielectric stack  30 . The dielectric stack  30  may have a total thickness of from 0.4 to 620 nanometers. The dielectric stack  30  total thickness should not exceed 1200 nanometers as light is reflected in the visible range and thicknesses greater than that would affect the visible spectrum. In one aspect, the high and low refractive index materials may have a refractive index of from 1.45 to 2.7 as measured at the wavelength of 600 nanometers. 
     Additionally, the thickness of each layer  25  of the dielectric stack  30  may be different or the same as other layers  25  within the stack  30 . Manipulation of the thicknesses of the various layers  25  in the dielectric stack  30  may be utilized to provide a desired appearance. In one aspect, the thickness of each layer may vary from 0.4 to 250 nanometers. 
     The metallic substrate material  10  should have a surface that is relatively free from surface roughness as marks and blemishes may create scatter of the visible spectrum at the surface. In one aspect, the reflectance at the surface of the optically modified three-dimensional object  5  should be relatively high, such as above 60% and even more preferably above 70%. However, various total reflectance properties may be adjusted and modified to mimic a specific surface appearance such that the three-dimensional object  5  can be tailored to have a desired appearance. 
     In another aspect, the appearance or reflected color of the three-dimensional object  5  may change with the viewing angle relative to the object. Alternatively, the appearance or reflected color of the object may remain constant with the viewing angle of the object. Various thicknesses and types of dielectric materials  15  may be selected. Thus, the appearance can be tailored to either change with the viewing angle or remain constant. 
     Various dielectric materials  15  may be utilized for the optical interference coating  20  applied to the three-dimensional object  5 . Dielectric materials  15  may include aluminum oxide, titanium oxide, silicon dioxide, tantalum oxide, niobium oxide, zirconium oxide, hafnium oxide, tin oxide, lanthanum oxide, yttrium oxide, cesium oxide, aluminum nitride, tantalum nitride, niobium nitride, titanium nitride, molybdenum nitride zirconium nitride, hafnium nitride, gallium nitride, titanium aluminum nitride, aluminum titanium oxide, indium doped tin oxide (ITO) and antimony doped tin oxide (ATO). The various dielectric materials  15  may have varying thicknesses when applied as layers  25  in a dielectric stack  30  and may be positioned at various strata within the layered structure to produce a desired appearance on the three-dimensional object  5 . As stated above, the dielectric stack may include various dielectric materials and in one aspect includes more than two different materials positioned within the stack. Various layer structures and thicknesses may be utilized with several exemplary embodiments detailed in the example section below. 
     In one aspect, the modified three-dimensional object  5  may include a layer of zirconium oxide  35  positioned on top of the at least one dielectric material  15 . The zirconium oxide layer  35  positioned as a top layer of a multilayer dielectric stack  30  may provide good chemical resistance to both acids and bases. The zirconium oxide layer  35  provides good chemical resistance to basic chemicals as well as provides a color correction or appearance modifying property. 
     The substrate material  10  may be selected from various metals including brass, nickel, steel, or combinations thereof. Additionally, the metal substrate  10  may further include a protective layer  40  applied to a surface of the metal substrate  10 . One example of a metal substrate material  10  having a protective layer  40  is a 70/30 brass object having a nickel coating applied thereto. Such a substrate material  10  may be used on a three-dimensional object that is potentially exposed to water to prevent the galvanic corrosion of the three-dimensional object. In this manner, if the multilayer dielectric stack  30  is compromised or damaged the galvanic corrosion resistance of the substrate material  10  will prevent further damage to the three-dimensional object  5 . 
     Again as stated above, the optical property of the substrate material  10  in combination with the at least one dielectric material  15  modifies the appearance of the three-dimensional object  5 . In one aspect, the appearance of the object may be designed to appear to be bright chrome without the use of chromium. Further details of exemplary coatings allowing for the appearance of an object to mimic bright chrome, as well as other appearances will be detailed in the example section below. 
     EXAMPLES 
     Example 1 
     Chromelike Appearance with Eleven Layer Stack of SiO2/TiO2/Al2O3 on Brass Substrate 
     Samples were prepared in the form of panels (size of 3 inch×8 inch with thickness of 0.032 inch) of 70/30 brass. The samples were polished using conventional polishing mops and compounds. They were placed in a conventional ultrasonic alkaline cleaner bath. The ultrasonic cleaner bath had a pH of 8.9-9.2, was maintained at a temperature of about 160-180 F, and contained the conventional and well known soaps, detergents, defloculants and the like. After the ultrasonic cleaning the samples were rinsed and dried. 
     The samples were placed in the Atomic Layer Deposition (ALD) reaction chamber. The process conditions, including pressure and temperature were adjusted to meet the requirements of the process chemistry and the substrate materials. A multi-layer coating of dielectric oxides shown in the Table 1 as shown below was deposited on the samples. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Example 1. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 SiO2 
                 40 
               
               
                 2 
                 TiO2 
                 40 
               
               
                 3 
                 SiO2 
                 59 
               
               
                 4 
                 TiO2 
                 53 
               
               
                 5 
                 SiO2 
                 18 
               
               
                 6 
                 TiO2 
                 39 
               
               
                 7 
                 Al2O3 
                 79 
               
               
                 8 
                 TiO2 
                 16 
               
               
                 9 
                 Al2O3 
                 25 
               
               
                 10 
                 TiO2 
                 59 
               
               
                 11 
                 Al2O3 
                 48 
               
               
                   
               
               
                 Total layer thickness = 476 nm. 
               
            
           
         
       
     
     Atomic Layer Deposition is a film deposition technique that is based on sequential, self-limiting gas-solid reactions. For the growth of a film, a pulse of a first precursor was vaporized from the external source and introduced into the reaction chamber. The vapor contacted the surface of the samples and reacted with the surface species. After an appropriate interval, the excess of the vapor and any volatile reaction products were evacuated with a purge gas such as N2. Subsequently, a second precursor vapor was introduced into the chamber and reacted with the surface of samples. Then the excess of the vapor and any volatile reaction products were evacuated with the purge gas again. Thus one cycle of a film growth was completed and the cycle was as follows: introducing a pulse of a first precursor vapor, keeping the precursor in the reaction chamber, exhausting the precursor vapor and any volatile reaction products by a purge gas, introducing a pulse of a second precursor vapor, keeping the precursor in the reaction chamber, and exhausting the precursor vapor and any volatile reaction products again by a purge gas. This cycle was repeated until achieving desirable thickness. For the growth of the TiO2 layer, possible precursors include the titanium halides, e.g. titanium tetrachloride (TiCl4) and H2O or the titanium alkoxides, e.g. titanium butoxide and H2O. The growth of ZrO2 and Al2O3 followed the same process except different precursors were used. The possible precursors can be found in the literatures. 
     The reflectance of the sample before and after deposition was measured at 7 degree of angle of incidence using Cary 500E Uv-Vis-NIR spectrophotometer. The reflectance of sample in the visible wavelength region changed after deposition of the multilayer coating as shown in the  FIG. 6 . This reflectance change resulted in the change of color of samples, which is clearly shown in Table 7. This sample has the reflectivity and appearance almost identical to that of a bright electroplated chrome surface. 
     The actual film thickness was measured from the cross sectional Transmission Electron Microscopy (TEM) image  FIG. 7 . The thickness of each layer in the sample was quite uniform and the coating is conformal. 
     Example 2 
     Chromelike Appearance with Nine Layer Stack of TiO2/SiO2/Al2O3/ZrO2 on Nickel Leveled Brass Having Good Chemical and Corrosion Resistance 
     Samples were prepared in the form of panels (size of 3 inch×8 inch with thickness of 0.032 inch) of 70/30 brass. The samples were polished using conventional polishing mops and compounds. They were placed in a conventional ultrasonic alkaline cleaner bath. The ultrasonic cleaner bath had a pH of 8.9-9.2, was maintained at a temperature of about 160-180 F, and contained the conventional and well known soaps, detergents, defloculants and the like. After the ultrasonic cleaning the samples were rinsed and placed in a conventional alkaline electro cleaner bath. The electro cleaner bath was maintained at a temperature of about 140-180 F, a pH of about 10.5-11.5, and contained standard and conventional detergents. The samples were then rinsed twice and placed in a conventional acid activator bath. The acid activator bath had a pH of about 2.0-3.0, was at an ambient temperature, and contained a sodium fluoride based acid salt. The samples were then rinsed twice and placed in a bright nickel plating bath. The bright nickel bath was generally a conventional bath which was maintained at a temperature of 130-150 F, a pH of about 4.0, contained NiSO4, NiCl2, boric acid, and brighters. A bright nickel layer was deposited on the sample surface. The nickel plated samples were rinsed three times and dried. 
     Similar to Example 1, the samples were placed in the ALD reaction chamber and a multi-layer coating of dielectric oxides as shown in Table 2 below was deposited on the samples. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Examples 2 and 4. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
               
                 1 
                 TiO2 
                 96 
               
               
                 2 
                 SiO2 
                 68 
               
               
                 3 
                 TiO2 
                 68 
               
               
                 4 
                 SiO2 
                 29 
               
               
                 5 
                 TiO2 
                 21 
               
               
                 6 
                 Al2O3 
                 81 
               
               
                 7 
                 TiO2 
                 55 
               
               
                 8 
                 Al2O3 
                 42 
               
               
                 9 
                 ZrO2 
                 20 
               
               
                   
               
               
                 Total layer thickness = 480 nm. 
               
            
           
         
       
     
     Example 3 
     Pink/Green Appearance at Different Angle of Incidence with Eight Layer TiO2/SiO2/Al2O3 Stack on Nickel Leveled Brass 
     As in the Example 2, the samples were cleaned and electroplated with a nickel layer. Similar to Example 2, the nickel plated samples were deposited with a multi-layer coating of dielectric oxides shown in the Table 3 using the Atomic Layer Deposition process described above. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Examples 3 and 5. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
               
                 1 
                 TiO2 
                 96 
               
               
                 2 
                 SiO2 
                 68 
               
               
                 3 
                 TiO2 
                 68 
               
               
                 4 
                 SiO2 
                 29 
               
               
                 5 
                 TiO2 
                 21 
               
               
                 6 
                 Al2O3 
                 81 
               
               
                 7 
                 TiO2 
                 55 
               
               
                 8 
                 Al2O3 
                 42 
               
               
                   
               
               
                 Total layer thickness = 460 nm. 
               
            
           
         
       
     
     Example 4 
     Yellowish Appearance with Nine Layer Stack of TiO2/SiO2/Al2O3/ZrO2 on Brass Having Good Chemical Resistance 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in Table 2 (see Example 2) above using Atomic Layer Deposition. 
     Example 5 
     Yellowing Appearance with Eight Layer TiO2/SiO2/Al2O3 Stack on Brass 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in Table 3 (see Example 3) using Atomic Layer Deposition process similar to the Example 1. 
     Example 6 
     Chromelike Appearance with Ten Layer SiO2/Al2O3/TiO2 on Brass 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in the Table 4 below using Atomic Layer Deposition process similar to the Example 1. 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Example 6. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 SiO2 
                 34 
               
               
                 2 
                 Al2O3 
                 18 
               
               
                 3 
                 TiO2 
                 31 
               
               
                 4 
                 Al2O3 
                 85 
               
               
                 5 
                 TiO2 
                 30 
               
               
                 6 
                 Al2O3 
                 178 
               
               
                 7 
                 TiO2 
                 6 
               
               
                 8 
                 Al2O3 
                 13 
               
               
                 9 
                 TiO2 
                 40 
               
               
                 10 
                 Al2O3 
                 86 
               
               
                   
               
               
                 Total layer thickness = 521 nm. 
               
            
           
         
       
     
     Example 7 
     Pink Color on Brass 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in the Table 5 using Atomic Layer Deposition process similar to the Example 1. 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Examples 7 and 9. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 TiO2 
                 23 
               
               
                 2 
                 SiO2 
                 91 
               
               
                 3 
                 TiO2 
                 47 
               
               
                 4 
                 SiO2 
                 50 
               
               
                 5 
                 TiO2 
                 56 
               
               
                 6 
                 SiO2 
                 118 
               
               
                   
               
               
                 Total layer thickness = 385 nm. 
               
            
           
         
       
     
     Example 8 
     Ten Layer TiO2/Al2O3 with Lower Processing Temperature 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in the Table 6 below using Atomic Layer Deposition process. The process was similar to the Example 1 except that the chamber was heated to a lower temperature than the temperature used in the example 1. 
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in the Example 8. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 TiO2 
                 20 
               
               
                 2 
                 Al2O3 
                 98 
               
               
                 3 
                 TiO2 
                 38 
               
               
                 4 
                 Al2O3 
                 83 
               
               
                 5 
                 TiO2 
                 51 
               
               
                 6 
                 Al2O3 
                 78 
               
               
                 7 
                 TiO2 
                 20 
               
               
                 8 
                 Al2O3 
                 70 
               
               
                 9 
                 TiO2 
                 62 
               
               
                 10 
                 Al2O3 
                 96 
               
               
                   
               
               
                 Total layer thickness = 616 nm. 
               
            
           
         
       
     
     Example 9 
     Pink Color on Brass Using E-Beam Deposition 
     As in the Example 1, the samples were subjected to ultrasonic alkaline cleaning, rinsing and drying. The samples were then deposited with a multi-layer coating of dielectric oxides shown in the Table 5 (see Example 7) using Electron Beam Physical Vapor Deposition. 
     Color Measurement Results for Examples 
     The color of the samples before and after deposition was measured using MinoLTA CR-200 calorimeter under D65 illumination. A specific color is defined by the combination of three specific parameters in which “L” is a measure of the lightness of an object, “a” is a measure of the redness or greenness, and “b” is a measure of yellowness or blueness. The color measurement results are shown in Table 7. It is clear that a multi-layer coating of dielectric oxides could color correct the reflectance of metals to create new colors. Specifically, the samples with the coating in the Example 2 could have the color almost identical to conventional chrome finish. 
     Chemical and Corrosion Test Results for Examples 
     Chemical tests were performed per the procedure as follows. Droplets (50 μl) of each chemical were placed on the samples and allowed to sit at ambient conditions for 16 hours. Visual observations were made after removing the droplets with a DI water rinse. The corrosion tests were performed per ASTM standard B-368 and visual observations were made after removing the samples out of the corrosion test chamber. The test results are shown in the Table 8. Chemical resistance especially base resistance is significantly improved by having ZrO2 as the outmost layer. Plated nickel layer provides good corrosion resistance in addition to dielectric oxides coating on the brass metal. The samples in the Example 2 having ZrO2 and nickel layers show the best chemical and corrosion resistance. 
     Example 10 
     Chromelike Appearance with 9 Layer SiO2/TiO2/Al2O3 on Steel 
     An optical design using 9 layers of SiO2/TiO2/Al2O3 was created to produce chromelike appearance on a steel substrate as shown in Table 9 below. 
     
       
         
           
               
             
               
                 TABLE 9 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in Example 10. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 SiO2 
                 61 
               
               
                 2 
                 TiO2 
                 50 
               
               
                 3 
                 SiO2 
                 91 
               
               
                 4 
                 TiO2 
                 42 
               
               
                 5 
                 SiO2 
                 21 
               
               
                 6 
                 TiO2 
                 18 
               
               
                 7 
                 Al2O3 
                 120 
               
               
                 8 
                 TiO2 
                 77 
               
               
                 9 
                 Al2O3 
                 66 
               
               
                   
               
               
                 Total layer thickness = 546 nm. 
               
            
           
         
       
     
     Example 11 
     Cyan or Blue Color on Nickel 
     An optical design using 13 layers of TiO2/Al2O3/SiO2/Ta2O5 was created to produce a blue color on a nickel substrate as shown in Table 10 below. 
     
       
         
           
               
             
               
                 TABLE 10 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in Example 11. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 TiO2 
                 65 
               
               
                 2 
                 Al2O3 
                 2 
               
               
                 3 
                 SiO2 
                 29 
               
               
                 4 
                 Al2O3 
                 13 
               
               
                 5 
                 TiO2 
                 120 
               
               
                 6 
                 Al2O3 
                 49 
               
               
                 7 
                 Ta2O5 
                 17 
               
               
                 8 
                 TiO2 
                 74 
               
               
                 9 
                 Ta2O5 
                 1 
               
               
                 10 
                 Al2O3 
                 28 
               
               
                 11 
                 Ta2O5 
                 30 
               
               
                 12 
                 TiO2 
                 48 
               
               
                 13 
                 SiO2 
                 124 
               
               
                   
               
               
                 Total layer thickness = 600 nm. 
               
            
           
         
       
     
     Example 12 
     Cyan or Blue Color on Nickel 
     A single layer of TiO2, 57 nm thick, deposited by ALD is used to create a blue color on a nickel substrate. 
     Example 13 
     Green Color on Nickel 
     An optical design using 15 layers of TiO2/Al2O3/SiO2/Ta2O5 is used to create a green color on a nickel substrate as shown in Table 11 below. 
     
       
         
           
               
             
               
                 TABLE 11 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in Example 13. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 TiO2 
                 46 
               
               
                 2 
                 Al2O3 
                 6 
               
               
                 3 
                 SiO2 
                 18 
               
               
                 4 
                 Al2O3 
                 6 
               
               
                 5 
                 TiO2 
                 71 
               
               
                 6 
                 Ta2O5 
                 3 
               
               
                 7 
                 TiO2 
                 79 
               
               
                 8 
                 Al2O3 
                 29 
               
               
                 9 
                 Ta2O5 
                 6 
               
               
                 10 
                 TiO2 
                 100 
               
               
                 11 
                 SiO2 
                 20 
               
               
                 12 
                 Al2O3 
                 24 
               
               
                 13 
                 Ta2O5 
                 29 
               
               
                 14 
                 TiO2 
                 45 
               
               
                 15 
                 SiO2 
                 94 
               
               
                   
               
               
                 Total layer thickness = 576 nm. 
               
            
           
         
       
     
     Example 14 
     Green Color on Nickel 
     A single layer of TiO2, 210.9 nm thick, deposited by ALD is used to create a green color on a nickel substrate. 
     Example 15 
     Purple Color on Nickel 
     An optical design using 9 layers of TiO2/SiO2/Al2O3/Ta2O5 is used to create a purple color on a nickel substrate as shown in Table 12 below. 
     
       
         
           
               
             
               
                 TABLE 12 
               
             
            
               
                   
               
               
                 The multi-layer coating of dielectric oxides in Example 15. 
               
            
           
           
               
               
               
            
               
                 Layer 
                 Material 
                 Thickness (nm) 
               
               
                   
               
            
           
           
               
               
               
            
               
                 1 
                 TiO2 
                 42 
               
               
                 2 
                 SiO2 
                 86 
               
               
                 3 
                 Al2O3 
                 10 
               
               
                 4 
                 SiO2 
                 42 
               
               
                 5 
                 TiO2 
                 59 
               
               
                 6 
                 Ta2O5 
                 20 
               
               
                 7 
                 Al2O3 
                 16 
               
               
                 8 
                 Ta2O5 
                 9 
               
               
                 9 
                 TiO2 
                 28 
               
               
                   
               
               
                 Total layer thickness = 312 nm. 
               
            
           
         
       
     
     Example 16 
     Purple Color on Nickel 
     A single layer of TiO2, 45.6 nm thick, deposited by ALD is used to create a purple color on a nickel substrate. 
     Example 17 
     Inventive Coating on Three Dimensional Faucet Part 
     An optical interference coating was deposited on to a faucet handle by atomic layer deposition. The optical interference stack, 9 layer TiO2/SiO2/Al2O3/ZrO2 stack, was the optical interference coating that was used as shown in Table 2 (see Example 2). The optical effect of a chromelike appearance with the multilayer stack was maintained around the entire part, thus proving the manufacturability of this process. 
     
       
         
           
               
             
               
                 TABLE 7 
               
             
            
               
                   
               
               
                 Color space of various samples. 
               
            
           
           
               
               
               
               
               
            
               
                   
                   
                 Nickel 
                   
                   
               
               
                 Color 
                   
                 Plated 
                 Conventional 
                 Examples 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Space 
                 Brass 
                 Brass 
                 Chrome Finish 
                 1 
                 2 
                 3 
                 4 
                 5 
                 6 
                 7 
                 8 
                 9 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
               
               
            
               
                 L 
                 72.6 
                 67.1 
                 68.5 
                 74.8 
                 67.1 
                 67.7 
                 76.7 
                 75.7 
                 75.6 
                 66.3 
                 67.3 
                 65.4 
               
               
                 a 
                 −2.2 
                 0.5 
                 −0.5 
                 −1.0 
                 1.9 
                 17.1 
                 −5.7 
                 2.0 
                 −0.3 
                 24.8 
                 18.7 
                 30.8 
               
               
                 b 
                 26.2 
                 4.8 
                 −1.7 
                 2.2 
                 −1.7 
                 −9.1 
                 23.9 
                 14.3 
                 5.5 
                 −9.7 
                 2.9 
                 −13.7 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 8 
               
             
            
               
                   
               
               
                 Chemical and corrosion tests of samples. 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Example 2 
                 Example 3 
                 Example 4 
                 Example 5 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 NaOH 6N 
                 No visual effect 
                 Coating totally lost 
                 Very slight haze 
                 Coating totally lost 
               
               
                 Phosphoric acid 
                 No visual effect 
                 Discoloration 
                 Slight discoloration 
                 Slight discoloration 
               
               
                 42.5% 
               
               
                 HCl 6N 
                 Slight haze 
                 Discoloration 
                 Discoloration 
                 Discoloration 
               
               
                 Methanol 100% 
                 No visual effect 
                 No visual effect 
                 No visual effect 
                 No visual effect 
               
               
                 Triton X-100 
                 No visual effect 
                 No visual effect 
                 No visual effect 
                 Very slight haze 
               
               
                 100% 
               
               
                 Corrosion test 
                 No visual effect 
                 A few tiny spots with 
                 Significant corrosion 
                 Significant corrosion 
               
               
                 96 hours 
                   
                 coating peeling 
                 and coating peeling 
                 and coating peeling