US20170088954A1

US20170088954A1 - Micro alloying for function modification

Info

Publication number: US20170088954A1
Application number: US15/266,286
Authority: US
Inventors: Yoshihiko Yokoyama; Kazuya Takagi; Naoto Matsuyuki
Original assignee: Apple Inc
Current assignee: Apple Inc
Priority date: 2015-09-30
Filing date: 2016-09-15
Publication date: 2017-03-30

Abstract

Methods and compositions of applying metallic coatings, or altering metallic compositions, are described. Metallic coatings are deposited on metallic substrates and treated with pulsed radiation, such a pulsed electron beam. The resulting metal substrate can have a metallic coating and/or altered surface chemistry.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims the benefit under 35 U.S.C. §119(e) of U.S. Patent Application No. 62/235,096, entitled “MICRO ALLOYING FOR FUNCTION MODIFICATION,” filed on Sep. 30, 2015, which is incorporated herein by reference in its entirety.

FIELD

The disclosure relates generally to metal substrates and related methods. More particularly, the disclosure relates to metal substrates coated with metallic glass, and methods of coating a metal substrate with a metallic glass.

BACKGROUND

Metallic glasses (also referred to herein as amorphous alloys and glassy alloys) are metallic alloys that do not have a crystalline structure. Instead, their structure is amorphous. Metallic glasses have a number of beneficial material properties that make them viable for use in various engineering applications.
Metallic glasses having specific cosmetic properties can be difficult to design. Cosmetic properties of a metal or metallic glass are properties of the surface chemistry of the metal or metallic glass. Further, metallic glasses can be difficult to use as a surface coating in conventional methods.
These and other needs are provided by the present disclosure.

SUMMARY

The present disclosure generally relates to metals comprising a metal coating on a metal substrate and methods for applying a metal coating onto a metal substrate using micro-alloying.
In one aspect, the disclosure is directed to a method of micro-alloying a metallic glass onto a metal substrate. In one embodiment, a metallic glass coating is deposited on a metal substrate to form a metallic glass coated surface. Pulsed radiation is applied to the metallic glass coated surface to adhere the metallic glass to the metal substrate. In certain variations, the pulsed radiation is a pulsed electron beam. In some variations, the metallic glass diffuses into the metal surface. In certain variations, the metallic glass can form a concentration gradient in the metal substrate surface.
In another aspect, the disclosure is directed to a method of modifying the chemical composition of a metal substrate. In some embodiments, the metal substrate may be a metallic glass substrate. In some embodiments, a metallic glass coating is deposited on a metal substrate or metallic glass substrate to form a coated metallic glass. Pulsed radiation is applied to the coated metallic glass to form a metallic glass with altered chemical composition.
In certain variations of the methods described herein, the pulsed radiation is a pulsed electron beam. In certain further variations, the resulting metal or metallic glass has an altered chemical composition from the original substrate. In additional variations, the coated metal or chemically altered metallic glass has a different color than the original metal or metallic glass substrate. In other variations, the coated metal or chemically altered metallic glass can have a greater hardness than the original metal or metallic glass substrate. The metals and metallic glasses can be further treated, such as by oxidation, to have altered cosmetic properties.
The disclosure is also directed to metals and metallic glasses having altered surface chemistry, as described herein.
Additional embodiments and features are set forth in part in the description that follows, and will become apparent to those skilled in the art upon reading of the specification. A further understanding of the nature and advantages of the present disclosure can be realized by reference to the remaining portions of the specification and the drawings, which forms a part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the following figures and description illustrate specific embodiments and examples, the skilled artisan will appreciate that various changes and modifications may be made without departing from the spirit and scope of the disclosure.

FIG. 1A depicts a schematic illustration of a metallic glass surface coating onto a crystalline substrate using a pulsed electron beam, in accordance with aspects of the disclosure.

FIG. 1B depicts a schematic illustration of a metallic glass coating onto a metallic glass substrate using pulsed electron beam radiation, in accordance with aspects of the disclosure.

FIG. 2 depicts an example of altering the color of a metallic glass by altering the chemistry of the metallic glass, in accordance with aspects of the disclosure.

FIG. 3 depicts formation of a dark color by depositing a Cu metallic glass coating on a Zr-containing metallic glass substrate, in accordance with aspects of the disclosure.

FIG. 4 depicts a portable electronic device having a micro-alloyed metallic glass coated metal substrate on a housing component, in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodiments described herein and illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.
In certain aspects, the disclosure is directed to metals having a metallic coating on a metallic substrate and methods for applying a metal coating onto a metal substrate using micro-alloying. In certain embodiments, the metallic coating may be a metallic glass coating. In other embodiments, the metallic substrate may be crystalline or metallic glass. In certain embodiments, the methods of the disclosure comprise micro-alloying a metallic coating onto a metallic substrate using pulsed radiation.
In one aspect, the disclosure is directed to a metal substrate coated with a metallic glass, and methods of micro-alloying a metal substrate with a metallic glass. In accordance with the present disclosure, the metallic glass may be applied to the metal substrate using pulsed radiation micro-alloying, as described herein.
In certain embodiments, a metallic glass coating is deposited on the surface of the metallic substrate. Pulsed radiation is applied to the metallic glass coated surface. The metallic glass adheres to, and optionally diffuses into (i.e., becomes part of), the metallic glass coated surface of the metallic substrate. The resulting metallic glass coated surface can have characteristics of metallic glass, including a harder surface than the metallic substrate, greater corrosion resistance, and/or altered color or texture.
FIG. 1A depicts a schematic illustration of pulsed radiation micro-alloying in accordance with an embodiment of the disclosure. As shown, a metallic glass surface is coated onto a crystalline metal substrate using a pulsed electron beam. Metallic glass film 102 is deposited on the surface of a metal substrate, in this embodiment a metal crystalline substrate 104. Pulsed radiation is then applied to the coated surface as an electron beam. The electron beam allows the metallic glass coating to form and adhere to the crystalline substrate. In certain embodiments, the metallic glass coating diffuses in the crystalline matrix of the metallic substrate to form a mixture 106 above a crystalline portion 108 of the metallic substrate. The resulting metallic glass coated metal substrate can have several characteristics of metallic glasses. These characteristics can include a harder surface, a higher corrosion resistance, and/or color and texture modification.
In other embodiments, the disclosure is directed to a metallic glass substrate coated with a metallic coating, and methods of coating a metallic glass substrate with a metallic coating. The metallic coating may be crystalline or metallic glass. In accordance with the disclosure, a metallic coating is deposited on a metallic glass substrate. Pulsed radiation is applied to the coated metallic glass substrate. The metallic coating adheres to, and optionally diffuses into (i.e., becomes part of), the metallic glass substrate. In various embodiments, the resulting metallic glass surface can have harder surface, greater corrosion resistance, desired color based on oxidation of the metallic glass coating, and/or modified texture.
FIG. 1B depicts a schematic illustration of pulsed radiation micro-alloying in accordance with another embodiment of the disclosure. As shown, a metallic surface is coated onto a metallic glass substrate using a pulsed electron beam. Metal coating 110 is deposited on metallic glass substrate 112. Both metal coating 110 and metallic glass substrate 112 have a specific chemical composition. When pulsed radiation is applied to the coated metallic glass substrate, the metallic coating becomes diffuses into (i.e., becomes part of) the metallic glass substrate, to form a metallic glass mixture 114 above a metallic glass portion 116 (metallic glass portion 116 has the same composition as the metallic glass substrate). The surface chemistry of the resultant metallic glass substrate has an altered chemical composition that can have altered surface and cosmetic properties from those of the original metallic glass substrate. As described above, metal coating 110 may be crystalline or metallic glass.
The metallic glass can form a concentration gradient in the metallic substrate. For example, the concentration gradient can extend 10 microns, 20 microns, 30 microns, 40 microns, or 50 microns into the metal substrate surface. The gradient can depend on the intensity of the pulsed radiation applied to the metallic glass coated surface during micro-alloying.
In various additional aspects, the color of the metal substrate can be altered by adding metallic glass to the metal surface. By altering the chemical composition, the color of the metal surface can be changed to that of a different alloy. Such changes can be used to provide a single color on the metal surface, or a different color on at different portions of the metal surface.
Any suitable pulsed radiation source and methodology known in the art may be used in connection with the present disclosure. Pulsed radiation sources can include, but are not limited to, electron beams, pulsed lasers, quartz flash lamps, and xenon arc lamps. In particular embodiments, the pulsed radiation is a pulsed electron beam. The pulses of radiation can be on the order of microseconds, nanoseconds, or picoseconds. When pulsed electron beams are used, the pulses can be on the microsecond time scale.
Without wishing to be limited to any theory or mode of action, the pulsed (ion/electron/laser) beam radiation allows the metallic glass coated substrate to be heated and cooled very rapidly. Rapid heating and cooling allows for quality improvement of metallic glass due to both elimination of any pre-existing crystalline component and structure rejuvenation.
In accordance with aspects of the disclosure, characteristics of metal or metallic glass coated metal substrate can be controlled, e.g., by controlling the composition of the metal/metallic glass coating and/or controlling the micro-alloying of the metal or metallic glass coating into metallic substrate. For instance, in certain embodiments, different characteristics can be obtained by controlling the composition of the metal/metallic glass coating. In other embodiments, different characteristics may be obtained by controlling the concentration of metal/metallic glass coating diffused into the metal substrate. In this regard, the depth of micro-alloying of the metal coating may be controlled via controlling the thickness of the coating, controlling the duration and/or intensity of pulsed radiation, and combinations thereof. In certain variations, the metal coating may diffuse into the metal substrate by a depth of at least one micron, at least two microns, at least three microns, at least four microns, or at least five microns.
In certain aspects of the disclosure, the thickness of the metal or metallic glass coating and the depth of diffusion of the metal or metallic glass coating will thereby impact the characteristics of the metal or metallic glass coated metal substrate. For instance, in certain embodiments, a thicker metallic glass coating, and a deeper diffusion into the metal substrate will result in incorporation of more characteristics of the metallic glass coating into the metal substrate. Again, these characteristics can include surface hardness, surface corrosion, surface color and surface texture. It will be understood by those skilled in the art that metallic glasses frequently have increased surface hardness and improved surface corrosion than the equivalent crystalline metal surface.
The metal or metallic glass coating can be in any form suitable to apply to the metal substrate. For example, the metal or metallic glass coating can be in the form of a film, sheet, ribbon, pellets, or powder. In certain particular embodiments, the metal substrate can be in the form a film.
Any metal or metallic glass substrate can be used in the methods disclosed herein. In various embodiments, the substrate can be any metal metallic glass substrate known in the art. Likewise, the metallic coating can be any metal known in the art. In some variations, the metallic coating can be crystalline. In other variations, the metallic coating can be metallic glass.
As used herein, the terms metallic glass, metallic glass alloy, metallic glass-forming alloy, amorphous metal, amorphous alloy, bulk solidifying amorphous alloy, BMG alloy, and bulk metallic glass alloy are used interchangeably.
In various embodiments, the metallic glass can be a nickel (Ni) based alloy, iron (Fe) based alloy, copper (Cu) based alloy, zinc (Zi) based alloy, zirconium (Zr) based alloy, gold (Au)-based alloy, platinum (Pt) based alloy, palladium (Pd) based alloy, or any other metallic glass. Similarly, metallic glass described herein as a constituent of a composition or metallic glass part can be of any type. As recognized by those of skill in the art, metallic glasses may be selected based on and may have a variety of potentially useful properties. In particular, metallic glasses tend to be stronger than crystalline alloys of similar chemical composition.
The metallic glass can comprise multiple transition metal elements, such as at least two, at least three, at least four, or more, transitional metal elements. The metallic glass can also optionally comprise one or more nonmetal elements, such as one, at least two, at least three, at least four, or more, nonmetal elements. A transition metal element can be any of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, rutherfordium, dubnium, seaborgium, bohrium, hassium, meitnerium, ununnilium, unununium, and ununbium. In one embodiment, a metallic glass containing a transition metal element can have at least one of Sc, Y, La, Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. Depending on the application, any suitable transitional metal elements, or their combinations, can be used.
Depending on the application, any suitable nonmetal elements, or their combinations, can be used. A nonmetal element can be any element that is found in Groups 13-17 in the Periodic Table. For example, a nonmetal element can be any one of F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge, Sn, Pb, and B. Occasionally, a nonmetal element can also refer to certain metalloids (e.g., B, Si, Ge, As, Sb, Te, and Po) in Groups 13-17. In one embodiment, the nonmetal elements can include B, Si, C, P, or combinations thereof. Accordingly, for example, the alloy can comprise a boride, a carbide, or both.
In some embodiments, the metallic glass composition described herein can be fully alloyed. The term fully alloyed used herein can account for minor variations within the error tolerance. For example, it can refer to at least 90% alloyed, such as at least 95% alloyed, such as at least 99% alloyed, such as at least 99.5% alloyed, such as at least 99.9% alloyed. The percentage herein can refer to either volume percent or weight percentage, depending on the context. These percentages can be balanced by impurities, which can be in terms of composition or phases that are not a part of the alloy. The alloys can be homogeneous or heterogeneous, e.g., in composition, distribution of elements, amorphicity/crystallinity, etc.
The metallic glass can include any combination of the above elements in its chemical formula or chemical composition. The elements can be present at different weight or volume percentages. Alternatively, in one embodiment, the above-described percentages can be volume percentages, instead of weight percentages. Accordingly, a metallic glass can be zirconium-based, titanium-based, platinum-based, palladium-based, gold-based, silver-based, copper-based, iron-based, nickel-based, aluminum-based, molybdenum-based, and the like. The metallic glass can also be free of any of the aforementioned elements to suit a particular purpose. For example, in some embodiments, the metallic glass, or the composition including the metallic glass, can be substantially free of nickel, aluminum, titanium, beryllium, or combinations thereof. In one embodiment, the alloy or the composite is completely free of nickel, aluminum, titanium, beryllium, or combinations thereof.
The afore described metallic glass can further include additional elements, such as additional transition metal elements, including Nb, Cr, V, and Co. The additional elements can be present at less than or equal to about 30 wt %, such as less than or equal to about 20 wt %, such as less than or equal to about 10 wt %, such as less than or equal to about 5 wt %. In one embodiment, the additional, optional element is at least one of cobalt, manganese, zirconium, tantalum, niobium, tungsten, yttrium, titanium, vanadium and hafnium to form carbides and further improve wear and corrosion resistance. Further optional elements may include phosphorous, germanium and arsenic, totaling up to about 2%, and preferably less than 1%, to reduce melting point. Otherwise incidental impurities should be less than about 2% and preferably 0.5%.
In some embodiments, a metallic glass composition can include a small amount of impurities. The impurity elements can be intentionally added to modify the properties of the composition, such as improving the mechanical properties (e.g., hardness, strength, fracture mechanism, etc.) and/or improving the corrosion resistance. Alternatively, the impurities can be present as inevitable, incidental impurities, such as those obtained as a byproduct of processing and manufacturing. The impurities can be less than or equal to about 10 wt %, such as about 5 wt %, such as about 2 wt %, such as about 1 wt %, such as about 0.5 wt %, such as about 0.1 wt %. In some embodiments, these percentages can be volume percentages instead of weight percentages. In one embodiment, the glassy alloy sample/composition consists essentially of the glassy alloy (with only a small incidental amount of impurities). In another embodiment, the composition includes a glassy alloy (with no observable trace of impurities).
As described above, the metal substrates or metallic glass surfaces can have specific color characteristics as described by the L*, a*, and b* color spectrum. These color characteristics can be altered by the methods disclosed herein.
Color is determined by the wavelength of light that is reflected or transmitted without being absorbed, assuming incident light is white light. The visual appearance of objects may vary with light reflection or transmission. In some embodiments, color may be quantified by parameters L*, a*, and b*, where L* stands for light brightness, a* stands for color between red and green, and b* stands for color between blue and yellow. For example, L* values less than 50 have a grey to black color, while L* near 0 suggest a dark color toward the black end of the spectrum.
For color measurement, testing equipment, such as X-Rite Color i7 XTH, X-Rite Coloreye 7000 may be used. These measurements are according to CIE/ISO standards for illuminants, observers, and the L* a* b* color scale. For example, the standards include: (a) ISO 11664-1:2007(E)/CIE S 014-1/E:2006: Joint ISO/CIE Standard: Colorimetry—Part 1: CIE Standard Colorimetric Observers; (b) ISO 11664-2:2007(E)/CIE S 014-2/E:2006: Joint ISO/CIE Standard: Colorimetry—Part 2: CIE Standard Illuminants for Colorimetry, (c) ISO 11664-3:2012(E)/CIE S 014-3/E:2011: Joint ISO/CIE Standard: Colorimetry—Part 3: CIE Tristimulus Values; and (d) ISO 11664-4:2008(E)/CIE S 014-4/E:2007: Joint ISO/CIE Standard: Colorimetry—Part 4: CIE 1976 L* a* b* Colour Space.
In some aspects, a metallic glass coating can be selected such that the coated metal acquires a specific color. The surface chemistry can have a specific composition corresponding to various cosmetic properties. Alternatively, the coated metal can be oxidized to form particular cosmetic properties.
Where the composition of a metallic or metallic glass substrate is altered by the disclosed methods, the metallic glass substrate can have altered properties based on the altered elemental composition. In some aspects, the cosmetics of the metallic glass differ from the cosmetics in the original metal substrate or metallic glass substrate. For example, the metal substrate can have a different color than the metallic glass coated substrate based on the L* a* b* color scheme. In such instances, the composition, thickness, deposition, etc. of the metallic coating can be selected such that the micro-alloy composition of the coated metallic substrate can be altered to a specific chemistry.
In some variations, the metallic glass coated surface or altered metallic glass composition can have grey to black color. In some variations, the L* value of the alloys is from 0 to 50. In other variations, the L* value is less than 40. In some variations, the L* value is less than 30. In some variations, the L* value is less than 20. In some additional variations, the L* value is less than 10. In some aspects, the metallic glass coated surface or altered metallic glass composition can be oxidized to form a darker color (such as when the alloy includes darkening metals such as Zr).
In some variations, the altered metals can have a lighter color. In some aspects, the metallic glass coated surface or altered metallic glass composition can be selected to have a brighter color, for example when brightening metals such as Ir are added. In these instances, the color of the metallic glass coated surface or altered metallic glass composition can have an L* value from 50 to 100. In some variations, L* is greater than 60. In some variations, L* is greater than 70. In some variations, L* is greater than 80. In some variations, L* is greater than 90.
In some variations, the metallic glass coated surface or altered metallic glass composition have an a* from −10 to 10. In some variations, the metals have an a* from −5 to 5. In further variations, the altered metals disclosed herein have a b* from −20 to 10. In some variations, the metals have a b* from −15 to 0. In some variations, the metals have a b* from −10 to 0.
The surface color of an alloy can be changed by altering the chemical composition of the alloy. By adding an element and diffusing the element into the surface, different alloying elements can be added in different amounts to the composition. As such, in certain aspects of the disclosure, the color of a metallic glass can be altered by changing the elemental composition of the metallic glass, as described herein.
In various aspects, the depth and homogeneity of the alloy formed by pulse radiation micro-alloying can be controlled by controlling the duration and/or intensity of the pulsed radiation. For example, when electron beam radiation is used, the accelerate voltage of electron beam (Vc) can be controlled, thereby controlling the extent of the micro-alloying.
In various embodiments, other properties of coated metals or metallic glasses can be altered by changing the chemical composition of the metallic substrate. For example, the electrical conductivity of metallic glasses can be increased by adding chemically conductive elements to the coated metal or metallic glass. In various embodiments, surface coatings such as Au, Cu, and/or Pt group metals can be added to the metal or metallic glass to improve electrical conductivity of the alloy. Alternatively, metals or metallic glasses can be made more corrosion resistant by adding a more corrosion resistant metallic glass to the surface, or by altering the chemistry at the surface of a metallic glass using more corrosion resistant elements. In further aspects, metallic glass surface coatings can be used to reduce or remove of surface incongruities of the alloy.
The methods of micro-alloying, and the metals thereby produced, can be used in any metal containing device known in the art. For example, methods and metals can be used in a portable electronic device. FIG. 4 depicts a portable electronic device 400 having a micro-alloyed metallic glass coated metal substrate on a housing component 402. In the embodiment depicted in FIG. 4, the color of housing 402 changes between top portion 404 and bottom portion 406. As described herein, the bottom portion 406 of electronic device 400 appears as a darker color than top portion 404. As such, the surface of portable electronic device 400 can be controlled by micro-alloying. FIG. 4 is not limiting. Housing component 402 can be altered in a similar fashion, in any manner described herein.
The methods herein can be used in the fabrication of electronic devices using a metallic glass-containing part. An electronic device herein can refer to any electronic device known in the art. For example, the electronic device can be a telephone, such as a mobile phone, and a land-line phone, or any communication device, such as a smart phone, including, for example an iPhone®, and an electronic email sending/receiving device. The electronic device can be a part of a display, such as a digital display, a TV monitor, an electronic-book reader, a portable web-browser (e.g., iPad®), and a computer monitor. The electronic device can also be an entertainment device, including a portable DVD player, conventional DVD player, Blue-Ray disk player, video game console, music player, such as a portable music player (e.g., iPod®), etc. The electronic device can also be a part of a device that provides control, such as controlling the streaming of images, videos, sounds (e.g., Apple TV®), or the electronic device can be a controller (such as a remote control) for a different electronic device. The electronic device can be a part of a computer or its accessories, such as the hard drive tower housing or casing, laptop housing, laptop keyboard, laptop track pad, desktop keyboard, mouse, and speaker. The article can also be applied to a device such as a watch or a clock.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not target to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

EXAMPLES

The following non-limiting examples are provided to illustrate aspects of the disclosure.

Example 1

By way of example, FIG. 2 depicts an example of altering a color parameter by altering the chemistry of the metallic glass using the disclosed methods. FIG. 2 shows the relationship between the alloy composition parameter of Zr/Cu ratio and parameter b* in Lab color space.
LM-105 and LM-601 are commercialized bulk metallic glasses, and Experimental Alloy 1 and Experimental Alloy 2 are Zr₅₀Cu₄₀Al₁₀and Zr₆₀Cu₃₀Al₁₀metallic glasses, respectively. Alloy LM-105 differs from alloy LM-601 based on the molar ratio of Zr/Cu. A surface coating of Cu was then added to the surface of the metallic glass substrate and electron beam radiation was applied to micro-alloy the Cu coating in accordance with the present disclosure. After application of the electron beam radiation on the surface, the Zr/Cu ratio was further reduced by the addition of Cu coating. As shown in FIG. 2, as Zr/Cu ratio decreases, the measure of b* was reduced from approximately −18.00 to less than −2.00. In this regard, it was found that an optimized range for Zr/Cu to obtain a dark color (a b* value of about 0) may generally be in the range of about 1.1 to about 1.5.
In various aspects, the color of the metal or metallic glass can be formed with or without oxidizing the metal.

Example 2

In another example, FIG. 3 depicts formation of a dark color by depositing Cu on a Zr-containing metallic glass substrate. In FIG. 3, 100 nm, 500 nm, and 1000 nm of copper were deposited on a metallic glass substrate. FIG. 3 shows the color change obtained by micro-alloying in accordance with the present disclosure after oxidization annealing in air (380° C., 1 hr). The Vc of the pulsed electron beam was controlled to insure the homogeneity of the resulting surface alloy. By using 100 nm Cu plating thick and an electron beam at Vc of 30 kV, a darker surface was obtained. No luster was observed on the surface when 500 nm or 1000 nm Cu film were deposited and an electron beam at Vc 20 kV was used. By balancing the amounts of deposited metal and electron beam power, the chemical composition and resulting properties of the metallic glass could be controlled.
While this disclosure has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof, without departing from the spirit and scope of the disclosure. In addition, modifications may be made to adapt the teachings of the disclosure to particular situations and materials, without departing from the essential scope thereof. Thus, the disclosure is not limited to the particular examples that are disclosed herein, but encompasses all embodiments falling within the scope of the appended claims.

Claims

1. A method of micro-alloying a metallic glass coating onto a metal substrate, comprising:

depositing a metallic glass coating on the metal substrate to form a metallic glass coated surface on the metal substrate; and

applying pulsed radiation to the metallic glass coated surface to adhere the metallic glass coating to the metal substrate to form a micro-alloyed metallic glass coated metal substrate.

2. The method of claim 1, wherein the pulsed radiation is a pulsed electron beam.

3. The method of claim 1, wherein the metallic glass coating diffuses into the surface of the metal substrate.

4. The method of claim 1, wherein the metallic glass coating diffuses in a gradient into the surface of the metal substrate.

5. The method of claim 1, wherein the micro-alloyed metallic glass coated metal substrate exhibits surface characteristics of the metallic glass.

6. The method of claim 1, further comprising oxidizing the micro-alloyed metallic glass coated metal substrate.

7. The method of claim 1, wherein the metal substrate is a metallic glass substrate.

8. The method of claim 1, wherein the application of the pulsed radiation is controlled so as to control diffusion of the metallic glass coating into the surface of the metal substrate.

9. A method of modifying the chemical composition of a metallic glass comprising:

depositing a metallic coating on a metallic glass substrate to form a coated metallic glass; and

applying pulsed radiation to the coated metallic glass to form a metallic glass substrate with altered chemical composition from the metallic glass substrate.

10. The method of claim 9, further comprising oxidizing the metallic glass substrate with altered chemical composition.

11. The method of claim 9, wherein the metallic glass substrate with altered chemical composition has a different color than the metallic glass substrate.

12. The method of claim 9, wherein the metallic glass substrate with altered chemical composition has greater hardness than the metallic glass substrate.

13. The method of claim 9, wherein the metallic coating is a metallic glass coating.

14. The method of claim 9, wherein the pulsed radiation is a pulsed electron beam.

15. A metal comprising a metallic coating diffused into a metallic substrate.

16. The metal of claim 15, wherein the metallic substrate is a crystalline substrate and the metallic coating is a metallic glass.

17. The metal of claim 15, wherein the metallic glass has a concentration gradient from the surface into the metallic substrate.

18. The metal of claim 15, wherein the concentration gradient extends an average of 50 microns into the metal substrate surface.

19. The metal of claim 15, wherein both the metallic substrate and metallic coating are a metallic glass.

20. A metallic glass coated metal substrate produced by the method of claim 1.