WO2011063310A2

WO2011063310A2 - Physical vapor deposition (pvd) and cold anodization metal coloring

Info

Publication number: WO2011063310A2
Application number: PCT/US2010/057537
Authority: WO
Inventors: Rui Zhao; Reed John Niederkorn; Kan ZHENG; Jun Wang; Xianqiu Liu
Original assignee: Laird Technologies, Inc.
Priority date: 2009-11-20
Filing date: 2010-11-20
Publication date: 2011-05-26
Also published as: WO2011063310A3; CN102071448A

Abstract

Exemplary embodiments of the present disclosure include colored metallic articles, which may include cold anodized, niobium-coated metallic substrates. Also disclosed herein are exemplary embodiments of methods relating to and/or for providing colored metallic articles, which may include cold anodized, niobium-coated metallic substrates. In an example embodiment, an article generally includes an anodized, niobium-coated metallic substrate having a hardness equal to or greater than about 350 HV (the Vickers Diamond Pyramid Hardness Number). An exemplary embodiment of a method generally includes anodizing a niobium-coated metallic substrate, such as to a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number) and/or at a temperature within a temperature range from about 0 degrees Celsius to about 5 degrees Celsius and with an electrical current within an electrical current range not exceeding about 1.5 Amps.

Description

Attorney Docket No. 90621-000007/WO/POA

PHYSICAL VAPOR DEPOSITION (PVD) AND

COLD ANODIZATION METAL COLORING

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a PCT International Application of (and claims priority to) Chinese Patent Application Number 200910224612.8 filed November 20, 2009. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure generally relates to colored metallic articles and methods relating to and/or for providing colored metallic articles.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Portable terminals {e.g., cellular phones, etc.) are popular modes of communication. And, the portable terminal's aesthetic appearance, such as its color, is usually an important factor to a customer when selecting and purchasing a portable terminal. Another important factor is oftentimes the durability of the portable terminal.

SUMMARY

[0005] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0006] Exemplary embodiments of the present disclosure include colored metallic articles, which may include cold anodized, niobium-coated metallic substrates. Also disclosed herein are exemplary embodiments of methods relating to and/or for providing colored metallic articles, which may include cold anodized, niobium-coated metallic substrates.

[0007] In an example embodiment, an article generally includes an anodized, niobium-coated metallic substrate having a hardness equal to or greater than about 350 HV (the Vickers Diamond Pyramid Hardness Number).

[0008] An exemplary embodiment of a method generally includes anodizing a niobium-coated metallic substrate to a hardness equal to or greater Attorney Docket No. 90621-000007/WO/POA than about 350 HV (Vickers Diamond Pyramid Hardness Number), with an electrical current within an electrical current range and at a temperature within a temperature range conducive for increasing hardness of the niobium-coated metallic substrate.

[0009] Another exemplary embodiment of a method generally includes anodizing a niobium-coated metallic substrate at a temperature within a temperature range from about 0 degrees Celsius to about 5 degrees Celsius and with an electrical current within an electrical current range not exceeding about 1 .5 Amps.

[0010] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0011] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0012] FIG. 1 illustrates an exemplary embodiment of an article that includes or comprises a cold anodized, niobium-coated stainless steel substrate;

[0013] FIG. 2 is a process flow diagram illustrating an exemplary embodiment of a method relating to and/or for providing a colored metallic article which includes a cold anodized, niobium-coated metallic substrate;

[0014] FIG. 3 is a circuit diagram representing an exemplary circuit that may be used for controlling electrical current while cold anodizing an niobium- coated metallic substrate; and

[0015] FIG. 4 is a process flow diagram of another exemplary embodiment of a method relating to and/or for providing a colored metallic article which includes a cold anodized, niobium-coated metallic substrate.

DETAILED DESCRIPTION

[0016] Example embodiments will now be described more fully with reference to the accompanying drawings. Attorney Docket No. 90621-000007/WO/POA

[0017] Exemplary embodiments of the present disclosure include colored metallic articles, which may include cold anodized, niobium-coated metallic substrates. Also disclosed herein are exemplary embodiments of methods relating to and/or for providing colored metallic articles, which may include cold anodized, niobium-coated metallic substrates.

[0018] In an example embodiment, an article includes an anodized, niobium-coated metallic substrate having a hardness equal to or greater than about 350 HV (the Vickers Diamond Pyramid Hardness Number). The anodized, niobium-coated metallic substrate may include a metallic substrate {e.g., stainless steel substrate, titanium substrate, substrate made from another metal or alloy, etc.) having a hardness less than 350 HV and one or more niobium coatings. By way of example only, the metallic substrate may be made of titanium or stainless steel having a initial hardness of about 200 HV. In some examples, the metallic substrate may comprise a substrate {e.g., a substrate formed of metal, alloy, plastic, etc.) with one more layers or coatings {e.g., titanium layer or coating, one or more coatings or layers formed from other metals, alloys, etc.). In one particular example embodiment, the metallic substrate comprises stainless steel with a titanium layer that is more than 1 micrometer thick, such that the titanium thus formed an intervening layer between the stainless steel and niobium.

[0019] To increase the hardness, the niobium-coated metallic substrate may be cold anodized {e.g., at a temperature within a temperature range of 0 degrees Celsius to about 5 degrees Celsius, etc.) until the hardness is at least about 350HV or more. Increasing the hardness may improve scratch resistance, durability, wear characteristics, etc. By way of example, only, an anodized, niobium-coated metallic substrate may have a hardness equal to about 350 HV in some embodiments, or a hardness from about 400 HV to about 800 HV in other embodiments, or hardness equal to about 400 HV in other embodiments, or a hardness equal to about 800 HV in other embodiments. In some embodiments, the hardness may be tailored in accordance with the end-user or customer Attorney Docket No. 90621-000007/WO/POA requirements, such as by changing the thickness of the niobium coating(s) and/or changing one or more parameters {e.g., duration, etc.) of the anodizing process.

[0020] In some embodiments, niobium is deposited on a substrate via physical vapor deposition (PVD). Exemplary PVD processes that may be used for depositing niobium include magnet control sputtering, arc evaporation, evaporation, and/or iron sputtering. In addition, some embodiments may include more than one niobium coating or deposition. For example, some exemplary embodiments include first and second physical vapor depositions of niobium. In addition, some exemplary embodiments may include one or more intervening material layers or coatings (e.g., titanium layer or coating, chromium carbide layer or coating, chromium nitride layer or coating, titanium carbide, layer or coating, titanium nitride layer or coating, one or more coatings or layers formed from other metals, alloys, etc.) between the niobium and the base material(s) of the substrate (e.g., stainless steel, titanium substrate, other metals, alloys, non- metals, plastic, other base materials, etc.). In one particular example embodiment, the metallic substrate comprises stainless steel with a titanium layer or coating that is more than 1 micrometer thick. In such example embodiment, the niobium would be deposited on the titanium.

[0021] In various exemplary embodiments, the metallic substrate includes upper and lower sides or planar surfaces coated with niobium. Each of the upper and lower sides of the metallic substrate may include at least one niobium coating having a thickness of between about .1 micrometer and about 3 micrometers {e.g., .1 micrometer thickness, 1 micrometer thickness, 2 micrometer thickness, 3 micrometer thickness, etc.). Alternative embodiments may include a metallic substrate with only one of the upper and lower sides with a niobium coating that is about .1 micrometer to about 3 micrometers thick. Other embodiments may include edges of the metallic substrate being coated with niobium. Still further embodiments may include one or more niobium coatings having a thickness that doesn't fall within the range of .1 micrometer to 3 micrometers, such as a thickness greater than 3 micrometers. Attorney Docket No. 90621-000007/WO/POA

[0022] As noted above, the niobium-coated metallic substrate may be cold anodized to increase hardness. In addition to increased hardness, the cold anodizing also allows for selective coloring or color selection. During the anodizing process, the anodizing voltage determines the thickness of the oxide layer. In turn, the thickness of the oxide layer determines what color is produced. The color formed is dependent on the thickness of the oxide layer and is caused by the interference of light reflecting off the oxide surface with light traveling through it and reflecting off the underlying metal surface. Therefore, the color may be selected by controlling the anodizing voltage. In some exemplary embodiments, the anodizing voltage may fall within a range of about 20 volts to about 120 volts depending, for example, at least partially on the color choice.

[0023] With the exemplary processes and methods disclosed herein, exemplary embodiments of the present disclosure are capable of obtaining rich, uniform, and/or stable coloring across two-dimensional and three-dimensional surfaces. The coloring may be selected, adjusted, and/or tailored to meet certain end-user or customer requirements. This selective coloring may allow for customization, personalization, part identification via color schemes, improved aesthetic appearance, and/or enhanced customer appeal for products including selectively colored metallic articles, such as a housing, battery cover, or other exterior feature of an electronic device {e.g., laptop computer, computer gaming console, etc.) or portable terminal {e.g., cellular phone, etc.).

In addition, the coloring in various exemplary embodiments may also be reproducible, such as to specification of less than one percent. The anodizing process can generate a wide array of different colors including white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet.

[0024] Some exemplary embodiments include at least one resin coating {e.g., polyurethane resin, ultraviolet cured resin, other suitable polymers, etc.) on at least a portion {e.g., on top of, etc.) of the anodized, niobium-coated metallic substrate. The resin coating may provide anti-fingerprint protection to the article. And, the inventors hereof have recognized that the resin coating also Attorney Docket No. 90621-000007/WO/POA provides the unexpected result of increased durability. In turn, the increased durability may increase the longevity or lifespan and improve wear characteristics for the article {e.g., battery cover, electronic device exterior housing, handset or portable terminal exterior components, etc.) or product that includes the article, such as a cellular phone or other portable terminal, etc. The resin coating may also improve strength and hardness.

[0025] There are also disclosed herein exemplary embodiments of methods, such as methods relating to and/or for providing colored metallic articles. In an exemplary embodiment, a method includes anodizing a niobium- coated metallic substrate {e.g., a titanium-coated stainless steel substrate having a hardness of about 270 HV, etc.) to a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number), with an electrical current within an electrical current range {e.g., an electrical current range not exceeding about 1 .5 Amps, etc.) and at a temperature within a temperature range {e.g., about 0 degrees Celsius to about 5 degrees Celsius, etc.) conducive for increasing hardness of the niobium-coated metallic substrate. In another exemplary embodiment, a method includes anodizing a niobium-coated metallic substrate at a temperature within a temperature range from about 0 degrees Celsius to about 5 degrees Celsius and with an electrical current within an electrical current range not exceeding about 1 .5 Amps.

[0026] By way of example, the anodizing temperature may be 0 degrees Celsius, 5 degrees Celsius, or some temperature therebetween {e.g., 2 degrees Celsius, 2.5 degrees Celsius, 3 degrees Celsius, 4 degrees Celsius, etc.). In addition, the anodizing need not occur at a constant temperature during the entire anodizing process. Instead, the anodizing temperature may fluctuate during the anodizing process, such as from 0 degrees to 5 degrees in some embodiments. In other embodiments, the anodizing temperature may exceed 5 degrees Celsius and/or be less than 0 degrees during all or a portion of the anodizing process. As disclosed herein, the anodizing temperature preferably is or remains low enough such that the hardness of the niobium-coated metallic substrate is increased as a result of the anodizing. In comparison, anodizing at Attorney Docket No. 90621-000007/WO/POA room temperature (20 to 25 degrees Celsius) typically doesn't lead to any increase in a material's original hardness. In various exemplary embodiments, cold anodizing may be used to increase the hardness of a niobium-coated metallic substrate {e.g., titanium-coated, stainless steel substrate having an initial hardness of about 270 HV before anodizing and.10 micrometer or more thick titanium layer/coating, etc.) to a hardness of 350 HV or more {e.g., 350 HV, 400 HV, 800 HV, a hardness value within the range 400 HV to 800 HV, etc.).

[0027] The temperature range and electrical current range may allow for slower deposition, increased coating density, avoidance of electrical current penetration completely through the niobium coating on the metallic substrate, and/or more uniform coloring. For example, using a lower anodizing temperature {e.g., within a range of 0 degrees Celsius to 5 degrees, etc.) helps prevent the temperature of the anodizing solution from getting too high and the electrical current from penetrating through the niobium coating. It also can increase the coating density.

[0028] The electrical current may be controlled or suppressed during at least the early phases of the anodizing in order to keep the electrical current from exceeding 1 .5 Amps. During the early phases of anodizing, the initial electrical current tends to be relatively high if not controlled or suppressed. In exemplary embodiments, the electrical current may be controlled or suppressed such that at the beginning and during the early phases of anodizing, the electrical current may be between about 1 Amp and about 1 .5 Amps. Towards the end of the anodizing, the electrical current may be between about 0.01 Amps and about 0.10 Amps because after the color layer has been created (as disclosed herein), the surface will essentially operate or function as a relatively large resistor.

[0029] In various exemplary embodiments, the electrical current is controlled or suppressed by using a series 10-500 Ohm resistance {e.g., a resistor having a variable resistance over time or a resistor having a constant resistance). In operation, the series 10-500 Ohm resistance can decrease loop current to keep the electrical current under 1 .5 Amps during anodizing. In turn, this helps prevent higher electrical current penetrating through the niobium Attorney Docket No. 90621-000007/WO/POA coating. In addition, a lower electrical current may slow down the deposition rate and decrease the anodizing speed, which may make the anodizing process easier to control and/or allow for the color to be made more uniform.

[0030] The anodizing solution may include phosphoric acid (H3PO4), nitric acid (HNO3), sulfuric acid (H2SO4), water (H2O), and triethanolamine (TEA). In an exemplary embodiment, the anodizing solution includes one part phosphoric acid (H3PO4), two parts nitric acid (HNO3), four parts sulfuric acid (H2SO4), nine parts water (H2O), and one part triethanolamine (TEA). Alternative anodizing solutions may also be used in other embodiments.

[0031] As noted above, anodizing allows for selective coloring or color selection. This is because the anodizing process can generate a wide array of different colors including white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet. Accordingly, various exemplary embodiments of methods include controlling the anodizing voltage to selectively determine oxide thickness and thus select a color from a plurality of colors attainable by said anodizing including white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet, such that the anodized niobium-coated metallic substrate includes the selected color. In some exemplary embodiments, the anodizing voltage may fall within a range of about 20 volts to about 120 volts depending, for example, at least partially on the color choice.

[0032] In some embodiments, the method includes anodizing to an oxide thickness within a range from about .3 micrometers to about 2 micrometers. In some embodiments, the method includes anodizing for about .50 minutes to about 1 minute {e.g., 30 seconds, 40 seconds, 60 seconds, etc.) f Alternative embodiments may include longer or shorter anodizing durations and/or different anodized oxide thicknesses.

[0033] Before anodizing, exemplary methods disclosed herein may include depositing or coating niobium onto at least a portion of a metallic substrate {e.g., stainless steel, titanium, stainless steel with titanium coating or layer, stainless steel with one or more coatings or layers of chromium carbide, Attorney Docket No. 90621-000007/WO/POA chromium nitride, titanium carbide, and/or titanium nitride, etc.). This may entail fully coating or depositing niobium all sides of the metallic substrate, such as by performing one or more physical vapor deposition processes {e.g., magnet control sputtering, arc evaporation, evaporation, and/or iron sputtering. In addition, some exemplary embodiments may include one or more of stamping, surface treating, and/or electric polishing at least a portion of the metallic substrate before niobium is coated or deposited on the metallic substrate.

[0034] Some exemplary embodiments include performing a first physical vapor deposition (PVD) {e.g., magnet control sputtering, arc evaporation, evaporation, iron sputtering, etc.) of niobium on at least both of the upper and lower planar surfaces or sides {e.g., the whole product surface, etc.) of a metallic substrate (e.g., titanium-coated, stainless steel substrate, stainless steel substrate with a titanium layer thereon, etc.). During this first PVD niobium coating process, some particles may fall or drop down onto the surface of the substrate. The position of the dropped particle(s) would be exposed during anodizing process. To avoid this, some exemplary embodiments include niobium recoating {e.g., PVD, etc.) before the anodizing process. And, some exemplary embodiments also include ultrasonic washing before the niobium recoating, where that ultrasonic washing helps expose and prepare the unstable coating positions for the niobium recoating process. After ultrasonic washing, niobium may again be coated or deposited {e.g., PVD, etc.) to help ensure that the metallic substrate's upper and lower sides are fully coated by niobium and that the exposed positions from the first coating or deposition process are recoated with niobium. After both coating or deposition processes are completed, the niobium coating thickness may fall within a range from about .1 micrometer to about 3 micrometers. For example, the niobium coating thickness may be .1 , 1 micrometer, 2 micrometers, 3 micrometers. Or, for example, the niobium coating thickness may be less than about .1 micrometer or great than about 3 micrometers. Alternative embodiments may include only one PVD process that provides sufficiently good deposition of niobium such that the ultrasonic washing and niobium recoating processes may be eliminated. Attorney Docket No. 90621-000007/WO/POA

[0035] Some exemplary embodiments may also include applying, depositing, or coating resin {e.g., polyurethane resin, ultraviolet cured resin, other suitable polymers, etc.) before anodizing or after anodizing. As noted above, the resin coating may provide anti-fingerprint protection to the article, but the inventors hereof have also recognized that the resin coating provides the unexpected result of increased durability. In turn, the increased durability may increase the longevity or lifespan and improve wear characteristics for the article {e.g., battery cover, electronic device exterior housing, handset or portable terminal exterior components, etc.) or product that includes the article, such as a cellular phone or other portable terminal, etc. The resin coating may also improve strength and hardness.

[0036] With reference now to the figures, FIG. 1 illustrates an exemplary embodiment of an article 100 that includes a cold anodized, niobium- coated stainless steel substrate embodying one or more aspects of the present disclosure. As shown, the article 100 includes a first or upper layer 104 and second or lower layer 108 coated or deposited on a metallic substrate 1 12. The metallic substrate 1 12 may comprise stainless steel, titanium, or other suitable material. In this example, the upper layer 104 may comprise niobium that forms a color top layer having a thickness of .6 micrometers +/- .1 micrometer. The lower layer 108 may comprise chromium carbide, chromium nitride, titanium carbide, titanium nitride, and/or titanium that forms a hardness layer having a thickness of 2 micrometers +/- .3 micrometers. In addition, the specific dimensions, numerical values, and materials identified in this paragraph (as are all dimensions, numerical values, and materials set forth herein) are provided for purposes of illustration only and not for limitation, as embodiments disclosed herein may be configured differently to have different sizes, shapes, materials {e.g., other substrate materials, other coatings or depositions, etc.). For example, other embodiments may include substrate having only the color layer, but not both layers. Still other examples may include niobium that forms the color top layer and/or hardness layer. Attorney Docket No. 90621-000007/WO/POA

[0037] FIG. 2 is a process flow diagram illustrating various processes, operations, or steps (represented by boxes 204 through 228) of an exemplary embodiment of a method 200. As shown, the method 200 includes stamping and/or surface treating a substrate (e.g., titanium-coated, stainless steel substrate, etc.) at box 204. For example, one or more openings, windows, holes, or other surface features may be stamped into the metallic substrate depending on the particular end use {e.g., battery cover, electronic device exterior housing, handset or portable terminal exterior components, etc.). The substrate may undergo surface treatment, such as polishing or deburring process to remove burrs or sharp edges that might otherwise produce point discharge.

[0038] At box 208, the substrate may be electrically polished for the purpose of smoothing the sharp or cutting edge(s) of the substrate. By smoothing the sharp edge, the electric polishing may thus help avoid electrical current release that might otherwise occur at a sharp edge during anodizing.

[0039] At box 212, niobium may be coated or deposited on the upper and/or lower sides or planar surfaces of the substrate by physical vapor deposition (e.g., magnet control sputtering, arc evaporation, evaporation, iron sputtering, etc.).

[0040] Box 216 includes ultrasonic washing to help expose and prepare unstable coating positions for a niobium recoating process at box 220. During the first PVD niobium coating process at box 212, some particles may fall or drop down onto the surface of the substrate. The position of the dropped particle would be exposed during the anodizing process at box 224. To avoid this, the method 200 includes ultrasonic washing at box 216 and then a second niobium coating or depositing process at box 220. This helps ensure that the substrate's upper and lower sides are fully coated by niobium and that the exposed positions from the first coating or deposition process are recoated. Upon completion of the second coating or deposition process at box 220, the niobium coating thickness may have a thickness of between about .10 micrometer to about 3 micrometer, etc. Attorney Docket No. 90621-000007/WO/POA

[0041] Box 224 includes cold anodizing the niobium-coated metallic substrate to a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number) with an electrical current, e.g., not exceeding about 1 .5 Amps and at a temperature within a temperature range of about 0 degrees Celsius to about 5 degrees Celsius. Using an anodizing temperature of 0 degrees Celsius to 5 degrees helps prevent the temperature of the anodizing solution from getting too high and the electrical current from penetrating through the niobium coating. It also can increase the coating density. The electrical current may be controlled or suppressed such that at the beginning and during the early phases of anodizing, the electrical current may be between about 1 Amp and about 1 .5 Amps. Towards the end of the anodizing, the electrical current may be between about 0.01 Amps and about 0.10 Amps because after the color layer has been created (as disclosed herein), the surface will essentially operate or function as a relatively large resistor.

[0042] The anodizing solution may include phosphoric acid (H3PO4), nitric acid (HNO3), sulfuric acid (H2SO4), water (H2O), and triethanolamine (TEA). In an exemplary embodiment, the anodizing solution includes one part phosphoric acid (H3PO4), two parts nitric acid (HNO3), four parts sulfuric acid (H2SO4), nine parts water (H2O), and one part triethanolamine (TEA). Alternative anodizing solutions may also be used in other embodiments.

[0043] As noted above, anodizing allows for selective coloring or color selection. Thus box 224 may also include controlling the anodizing voltage to selectively determine oxide thickness and thus select a color from a plurality of colors attainable by said anodizing including white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet. In some exemplary embodiments, the anodizing voltage may fall within a range of about 20 volts to about 120 volts depending, for example, at least partially on the color choice.

[0044] At box 228, a resin coating may be applied, such as polyurethane resin, ultraviolet cured resin, other suitable polymers, etc. The resin coating may provide anti-fingerprint protection to the article. And, the inventors Attorney Docket No. 90621-000007/WO/POA hereof have also recognized that the resin coating provides the unexpected result of increased durability. In turn, the increased durability may increase the longevity or lifespan and improve wear characteristics for the article {e.g., battery cover, electronic device exterior housing, handset or portable terminal exterior components, etc.) or product that includes the article, such as a cellular phone or other portable terminal, etc. The resin coating may also improve strength and hardness.

[0045] FIG. 3 is a circuit diagram representing an exemplary circuit 300 that may be used for controlling electrical current while anodizing, such as during cold anodizing at box 224 of the method 200 (FIG. 2), cold anodizing at box 416 of the method 400 (FIG. 4), etc. As shown, the circuit 300 includes a DC power source 304 and a series 10-500 Ohm resistance 308, which may be a resistor having a variable resistance over time or a resistor having a constant resistance. Also shown in FIG. 3 are the electrodes 312 and 316 and anodizing tank or vessel 320. In operation, the series 10-500 Ohm resistance 308 can decrease loop current so as to keep the electrical current under 1 .5 Amps during anodizing. In turn, this helps prevent higher electrical current penetrating through the niobium coating. In addition, a lower electrical current may slow down the deposition rate and decrease the anodizing speed, which may make the anodizing process easier to control and/or allow for the color to be made more uniform. In exemplary embodiments, the electrical current may be controlled or suppressed such that at the beginning and during the early phases of anodizing, the electrical current may be between about 1 Amp and about 1 .5 Amps. Towards the end of the anodizing, the electrical current may be between about 0.01 Amps and about 0.10 Amps because after the color layer has been created (as disclosed herein), the surface will essentially operate or function as a relatively large resistor.

[0046] FIG. 4 is a process flow diagram illustrating various processes, operations, or steps (represented by boxes 404 through 420) of an exemplary embodiment of a method 400. As shown, method 400 includes only one physical vapor deposition of niobium at box 412 and does not include ultrasonic washing. Attorney Docket No. 90621-000007/WO/POA

This is unlike the illustrated method 200 that included ultrasonic washing at box 216 and a second niobium coating or deposition process at box 220. With method 400, the niobium coating or deposition process at box 412 provided better niobium deposition (without the dropped particles) such that ultrasonic washing and second niobium coating or deposition process was not necessary. The other processes, operations, or steps at boxes 404, 408, 416, an 420 of method 400 may be identical or similar to the corresponding boxes 204, 208, 224, and 228.

[0047] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0048] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. Attorney Docket No. 90621-000007/WO/POA

[0049] When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion {e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0050] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0051] Spatially relative terms, such as "inner," "outer," "beneath", "below", "lower", "above", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or Attorney Docket No. 90621-000007/WO/POA at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0052] The disclosure herein of particular values and particular ranges of values for given parameters are not exclusive of other values and ranges of values that may be useful in one or more of the examples disclosed herein. Moreover, it is envisioned that any two particular values for a specific parameter stated herein may define the endpoints of a range of values that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values could also be employed for the given parameter). Similarly, it is envisioned that disclosure of two or more ranges of values for a parameter (whether such ranges are nested, overlapping or distinct) subsume all possible combination of ranges for the value that might be claimed using endpoints of the disclosed ranges.

[0053] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.

Claims

Attorney Docket No. 90621-000007/WO/POA CLAIMS What is claimed is:

1 . A method comprising anodizing a niobium-coated metallic substrate to a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number), with an electrical current within an electrical current range and at a temperature within a temperature range conducive for increasing hardness of the niobium-coated metallic substrate.

2. A method comprising anodizing a niobium-coated metallic substrate at a temperature within a temperature range from about 0 degrees Celsius to about 5 degrees Celsius and with an electrical current within an electrical current range not exceeding about 1 .5 Amps.

3. The method of claim 2, wherein anodizing includes anodizing the niobium-coated metallic substrate to a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number).

4. The method of claim 1 , wherein the temperature range is from about 0 degrees Celsius to about 5 degrees Celsius.

5. The method of claim 1 , wherein the electrical current range does not exceed about 1 .5 Amps.

6. The method of claim 1 or 2, wherein at least one of the temperature range and/or electrical current range are predetermined to allow for slower deposition, increased coating density, avoidance of electrical current penetration through the niobium coating, and/or more uniform coloring.

7. The method of claim 1 or 2, wherein anodizing includes using an anodizing solution comprising phosphoric acid (H3PO4), nitric acid (HNO3), sulfuric acid (H2SO4), water (H2O), and triethanolamine (TEA).

8. The method of claim 7, wherein the anodizing solution includes one part phosphoric acid (H3PO4), two parts nitric acid (HNO3), four parts sulfuric acid (H2SO4), nine parts water (H2O), and one part triethanolamine (TEA).

9. The method of claim 1 or 2, further comprising coating at least a portion of a metallic substrate with niobium to thereby provide the niobium-coated metallic substrate. Attorney Docket No. 90621-000007/WO/POA

10. The method of claim 1 or 2, further comprising fully coating at least the upper and lower sides of a metallic substrate with niobium to thereby provide the niobium-coated metallic substrate.

1 1 . The method of claim 1 or 2, further comprising depositing niobium on at least a portion of a metallic substrate to thereby provide the niobium-coated metallic substrate.

12. The method of claim 1 1 , wherein depositing niobium includes at least one physical vapor depositing of niobium.

13. The method of claim 1 1 , wherein depositing niobium includes depositing niobium on at least the upper and lower sides of the metallic substrate.

14. The method of claim 1 1 , wherein depositing niobium includes magnet control sputtering, arc evaporation, evaporation, and/or iron sputtering.

15. The method of claim 1 or 2, wherein the method includes:

a first physical vapor depositing of niobium;

ultrasonic washing after the first physical vapor depositing of niobium; a second physical vapor depositing of niobium after the ultrasonic washing.

16. The method of claim 1 or 2, wherein the niobium-coated metallic substrate includes a niobium coating having a thickness within a range from about .1 micrometer to about 3 micrometers.

17. The method of claim 1 or 2, further comprising:

coating at least a portion of the niobium-coated metallic substrate with resin before anodizing; and/or

coating at least a portion of the anodized niobium-coated metallic substrate with resin after anodizing.

18. The method of claim 17, wherein the resin coating increases durability of the niobium-coated metallic substrate.

19. The method of claim 17, wherein the resin comprises polyurethane resin and/or ultraviolet cured resin. Attorney Docket No. 90621-000007/WO/POA

20. The method of claim 1 or 2, wherein anodizing includes controlling electrical current using a series 10-500 Ohm resistance.

21 . The method of claim 1 or 2, wherein anodizing includes controlling electrical current using a resistor having a variable resistance over time or a resistor having a constant resistance.

22. The method of claim 1 or 2, wherein anodizing includes suppressing initial electrical current during at least an early phase of the anodizing.

23. The method of claim 1 or 2, wherein the niobium-coated metallic substrate includes a metallic substrate comprising:

stainless steel; and/or

titanium; and/or

stainless steel and a titanium layer having a thickness of about .10 micrometer or more; and/or

a metal having a hardness less than 350 HV; and/or

a metal alloy having a hardness less 350 HV.

24. The method of claim 1 or 2, wherein anodizing allows selective coloring of the anodized niobium-coated metallic substrate.

25. The method of claim 1 or 2, wherein anodizing includes selecting a color from a plurality of colors attainable by said anodizing including white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet, such that the anodized niobium-coated metallic substrate includes the selected color.

26. The method of claim 1 or 2, wherein anodizing includes controlling the anodizing voltage to selectively determine oxide thickness and color.

27. The method of claim 1 or 2, wherein the method includes anodizing the niobium-coated metallic substrate to a hardness within a range from about 400 HV to about 800 HV.

28. The method of claim 1 or 2, wherein the method includes:

anodizing to an oxide thickness within a range from about .30 micrometers to about 2 micrometers; and/or Attorney Docket No. 90621-000007/WO/POA anodizing for about .5 minutes to about 1 minute.

29. The method of claim 1 or 2, wherein the metallic substrate comprises stainless steel and a titanium layer having a thickness of .10 micrometer or more, such that the hardness of the metallic substrate before anodizing is about 270 HV.

30. The method of claim 1 or 2, further comprising one or more of stamping, surface treating, and/or electric polishing at least a portion of the metallic substrate before niobium is coated or deposited on the metallic substrate.

31 . An article comprising an anodized, niobium-coated metallic substrate having a hardness equal to or greater than about 350 HV (Vickers Diamond Pyramid Hardness Number), the anodized, niobium-coated metallic substrate including a metallic substrate having a hardness less than 350 HV and one or more niobium coatings having a thickness of between about .1 micrometer and 3 micrometers.

32. The article of claim 31 , wherein the metallic substrate includes one or more sides all coated with niobium.

33. The article of claim 31 , wherein the metallic substrate includes one or more sides, each side including at least one niobium coating having a thickness of between about .1 micrometer and 3 micrometers.

34. The article of claim 31 , wherein the niobium coating comprises at least one physical vapor deposition of niobium.

35. The article of claim 31 , wherein the niobium coating comprises first and second physical vapor depositions of niobium.

36. The article of claim 31 , further comprising one or more resin coatings on at least a portion of the anodized niobium-coated metallic substrate.

37. The article of claim 36, wherein the one or more resin coatings are configured such that the article's durability is increased.

38. The article of claim 37, wherein the one or more resin coatings comprises polyurethane resin and/or ultraviolet cured resin. Attorney Docket No. 90621-000007/WO/POA

39. The article of claim 31 , wherein the metallic substrate comprises stainless steel and/or titanium.

40. The article of claim 31 , wherein the metallic substrate comprises one or more metals and/or one or more metal alloys.

41 . The article of claim 31 , wherein the metallic substrate comprises stainless steel and a titanium layer, such that the titanium layer is disposed between the niobium and stainless steel.

42. The article of claim 31 , wherein the article includes a color that is one of white, black, gray, gold, silver, champagne, brown, rose, red, orange, yellow, green, cyan, blue, indigo, and violet.

43. The article of claim 31 , wherein the anodized, niobium-coated metallic substrate has a hardness within a range from about 400 HV to about 800 HV.

44. The article of claim 31 , wherein the anodized, niobium-coated metallic substrate includes anodized oxide having a thickness within a range from about .3 micrometers to about 2 micrometers.

45. A portable terminal comprising the article of any one of claims 31 through 44.

46. The portable terminal of claim 45, wherein the anodized, niobium- coated metallic substrate comprises a battery cover and/or at least a portion of a housing.