System And Method of Forming a Non-Oxidizing Intimate Coating Over Various Metals

Description

The current application claims a priority to the U.S. provisional patent application Ser. No. 63/711,124 filed on Oct. 23, 2024.

FIELD OF THE INVENTION

The present invention generally relates to a method for forming an intimate coating of non-oxidizing conductive ternary alloys on the surfaces of various metals. The method protects the substrate from oxidation, enhances electrical conductivity, prevents deformation at high temperatures, and improves surface reflectivity.

BACKGROUND OF THE INVENTION

In many industries, durable, conductive, and oxidation-resistant coatings are essential to enhance the longevity and performance of materials exposed to harsh environmental conditions. Metals are particularly susceptible to oxidation and degradation when exposed to high temperatures, or reactive chemicals, which can compromise their electrical conductivity, structural integrity, and appearance. Applications ranging from electronics and industrial machinery to jewelry demand materials that can withstand such conditions. Traditional methods of preventing oxidation, such as plating and protective coatings, often degrade over time or fail to endure extreme temperatures. Furthermore, these coatings may not provide sufficient electrical conductivity for electronic components or solar cell batteries.

Therefore, an objective of the present invention is to provide users with a method for forming an intimate coating or a ternary alloy over a wide variety of substrates, including metals. This invention introduces a novel material of silver gallium film to form non-oxidizing conductive ternary alloys on the surface of a metal. Thus, the present invention protects various substrates from oxidation, enhances electrical conductivity, prevents deformation at high temperatures, and improves surface reflectivity.

SUMMARY OF THE INVENTION

The present invention is a method of forming an intimate coating (i.e. the coating alloys with the metal that adheres with no air at the interface) that is a non-oxidizing and conductive metal film on the surfaces of various metals. The film is formed by depositing a layer of Ag_xGa amalgam (where x ranges from 0.1 to 2 depending on the application) near room temperature over a metal substrate, followed by annealing the substrate up to its melting point. The coating protects the substrate from oxidation, enhances electrical conductivity, prevents deformation at high temperatures, and improves surface reflectivity. The invention's applications extend to electronic circuit boards, jewelry, mirror manufacturing, protective coatings for metals to prevent oxidation in harsh conditions, conductive paints, solar cells, and battery fabrication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the system of the present invention.

FIG. 2 is a flowchart illustrating an overall process for the method of the present invention.

FIG. 3 is a table illustrating optimum values of x in Ag_xGa and y in Ag₂GayM for metal substrates for the method of the present invention.

FIG. 4 is a schematic representation of direct heating (e.g., torch, radiation) of the silver-gallium film and the treatable apparatus to a melting point of the treatable apparatus, on an anti-vibration stage.

FIG. 5 is a schematic representation of a ternary crystal formation after high-temperature annealing of Ag_xGa on one of 24 listed metals.

FIG. 6 is a flowchart illustrating a subprocess performed over a vibrating platform.

FIG. 7 is a flowchart illustrating a subprocess performed over an anti-vibrating table.

FIG. 8 is a schematic representation of a crystalline structure of Ag2Ga3Cu within bulk copper, featuring a Ga2O3 layer at the surface exposed to air.

FIG. 9 is a table illustrating some properties of silver gallium intimate coating on iron and copper wires and sheets, in comparison with some original base materials.

DETAILED DESCRIPTION OF THE INVENTION

All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.

As a preliminary matter, it will readily be understood by one having ordinary skill in the relevant art that the present disclosure has broad utility and application. As should be understood, any embodiment may incorporate only one or a plurality of the above-disclosed aspects of the disclosure and may further incorporate only one or a plurality of the above-disclosed features. Furthermore, any embodiment discussed and identified as being “preferred” is considered to be part of a best mode contemplated for carrying out the embodiments of the present disclosure. Other embodiments also may be discussed for additional illustrative purposes in providing a full and enabling disclosure. Moreover, many embodiments, such as adaptations, variations, modifications, and equivalent arrangements, will be implicitly disclosed by the embodiments described herein and fall within the scope of the present disclosure.

Accordingly, while embodiments are described herein in detail in relation to one or more embodiments, it is to be understood that this disclosure is illustrative and exemplary of the present disclosure and is made merely for the purposes of providing a full and enabling disclosure. The detailed disclosure herein of one or more embodiments is not intended, nor is it to be construed, to limit the scope of patent protection afforded in any claim of a patent issuing here from, which scope is to be defined by the claims and the equivalents thereof. It is not intended that the scope of patent protection be defined by reading into any claim a limitation found herein that does not explicitly appear in the claim itself.

Thus, for example, any sequence(s) and/or temporal order of steps of various processes or methods that are described herein are illustrative and not restrictive. Accordingly, it should be understood that, although steps of various processes or methods may be shown and described as being in a sequence or temporal order, the steps of any such processes or methods are not limited to being carried out in any particular sequence or order, absent an indication otherwise. Indeed, the steps in such processes or methods generally may be carried out in various different sequences and orders while still falling within the scope of the present invention. Accordingly, it is intended that the scope of patent protection is to be defined by the issued claim(s) rather than the description set forth herein.

Additionally, it is important to note that each term used herein refers to that which an ordinary artisan would understand such term to mean based on the contextual use of such term herein. To the extent that the meaning of a term used herein—as understood by the ordinary artisan based on the contextual use of such term—differs in any way from any particular dictionary definition of such term, it is intended that the meaning of the term as understood by the ordinary artisan should prevail.

Furthermore, it is important to note that, as used herein, “a” and “an” each generally denotes “at least one” but does not exclude a plurality unless the contextual use dictates otherwise. When used herein to join a list of items, “or” denotes “at least one of the items” but does not exclude a plurality of items of the list. Finally, when used herein to join a list of items, “and” denotes “all of the items of the list”.

In reference to FIG. 1 through FIG. 9, the present invention is a system and method of applying a non-oxidizing and intimate coating. In order to accomplish the above-described functionality, the system used to execute the method of the present invention begins by providing a treatable apparatus, wherein the treatable apparatus is made of a specific material (Step A). The treatable apparatus is a device or surface over which the intimate coating has to be formed. While FIG. 1 shows the substrate as a flat surface, the invention also claims the same method for intimate coating other surface shapes, including but not limited to cylindrical shapes, tubular shapes, flat surfaces, and corrugated surfaces, as a few examples. In the preferred embodiment, the specific material is a metal, wherein the metal is selected from a group consisting of chromium, copper, cobalt, gold, hafnium, indium, iron, manganese, molybdenum, nickel, niobium, palladium, platinum, scandium, silver, vanadium, yttrium, zirconium, titanium, tantalum, rhodium, ruthenium, osmium, and tungsten.

As can be seen in FIG. 2, now that the system used to execute the method of the present invention has been described, it is possible to adequately describe an overall process for the method of the present invention. The overall process begins by coating at least one specific exterior surface of the treatable apparatus with a silver-gallium film (Step B). The at least one specific exterior surface is a single portion, multiple portions, or the entirety of the treatable apparatus, wherein the intimate coating is being formed. In the preferred embodiment, a chemical composition of the silver-gallium film is Ag_xGa, and a value of x is an atomic ratio between silver and gallium, wherein the value of x is optimized between a range of 0.1 to 2. In other words, the silver-gallium film is formed by depositing a layer of Ag_xGa amalgam (where x ranges from 0.1 to 2 depending on the application) near room temperature. Further, Step B is performed through a coating process selected from a group consisting of brushing, rolling, spraying, evaporation, sputtering, and electrochemical deposition. For example, the deposition of Ag_xGa may be performed using a high-temperature painting brush on the surface of specific exterior surface. As a second example, Ag_xGa may be deposited using a commercially available spray with a modified heating reservoir to heat up the Ag_xGa to the desired temperature. As a third example, the coating of Ag_xGa may be using one or a plurality of rollers, where the treatable apparatus is passed in between multiple spongy rollers coated with Ag_xGa. The Ag_xGa is constantly pumped into the roller from a reservoir to keep the rollers covered with the Ag_xGa mixture. By adjusting the flow of the Ag_xGa into the roller, the intimate coating thickness can be controlled to form a uniform intimate coating on the surface of the substrate or specific exterior surface of the treatable apparatus.

The overall process of the method of the present invention continues by annealing the silver-gallium film and the treatable apparatus up to a melting temperature of the specific material in order to coat the specific exterior surface with a ternary alloy, wherein the ternary alloy is made of the silver-gallium film and the specific material (Step C). Annealing is a heat treatment process that changes the physical and sometimes also the chemical properties of a material to increase ductility and reduce the hardness to make it more workable. The annealing process requires the material above its recrystallization temperature for a set amount of time before cooling. Annealing can occur in air or vacuum. Annealing at extreme temperatures (above the melting point of the substrate) requires a vacuum to prevent oxidation. As seen in FIG. 4, Ag₂Ga nano-microcrystals coexists with excess Ga within the Ag_xGa intimate coating prior to the annealing of the metal substrate, which is made from one of the 24 metals listed in this invention. The Ag₂Ga nano-microcrystals are primarily concentrated at the lower region of the Ag_xGa mixture, where they contribute to forming a stronger bond with the substrate even prior to the annealing. After annealing the resulting crystal is a ternary alloy of Ag₂Ga_yM with few atomic layers of gallium oxide forming above the ternary alloy, as shown in FIG. 5. More specifically, wherein the specific material is a metal M, the chemical composition of the ternary alloy is Ag₂Ga_yM, wherein a value of y is optimized between a range of 1.17 and 7.125. The composition of the ternary alloy for various different metals can be seen in FIG. 3.

The overall process continues by sanding the ternary alloy to a specific surface finish in order to form a protective intimate coating on the specific exterior surface (Step D). This process ensures that the final layer of intimate coating has the desired smoothness or surface finish. In other words, sanding the apparatus with various sanding products enable users to achieve the desired surface finish.

Thus, by following the method of the present invention, a coating layer of a ternary alloy of Ag₂Ga_yM is formed on the surface of metal M, protecting against oxidation, even at elevated temperatures. Additionally, Ag₂Ga_yM coating enhances the electrical conductivity, chemical stability, and mechanical strength of the metal M.

A more detailed description of the present invention follows.

An embodiment of the present invention is the annealing process in a stage with vibration capability to allow shaking of the binary and ternary nano and microcrystals in a micro-scale to affect the size and shape of binary and ternary multi-crystal forming in the intimate coating layer. In other words, the method of the present invention includes vibrating the silver-gallium film and the treatable apparatus during Step C.

In reference to FIG. 6, a subprocess of the present invention begins by providing a hot plate with a vibrating platform, wherein the hot plate is in thermal communication with the vibrating platform. In other words, the hot plate provides heat to the vibrating platform. Subsequently, the subprocess continues by placing the silver-gallium film and the treatable apparatus onto the vibrating platform. Vibration during low-temperature annealing improves the reaction of the Ag_xGa layer with the substrate surface and enhances the spreading of the Ag_xGa on the substrates. Accordingly, the subprocess continues by vibrating the silver-gallium film and the treatable apparatus with the vibrating platform. Subsequently, the subprocess continues by annealing the silver-gallium film and the treatable apparatus with the hot plate during Step C. More specifically, after the substrate is coated with Ag_xGa, the substrate must be annealed on the hotplate at temperatures between 200° C. and 550° C. for a few minutes to several hours, depending on the application. The substrate is then polished to achieve a more uniform coating before undergoing high-temperature annealing, which must not exceed the melting point of the substrate.

In another embodiment, the method of the present invention includes holding still the silver-gallium film and the treatable apparatus during step C. In other words, an embodiment of the method in this invention is an annealing process on an anti-vibration table, to eliminate external vibration to the specimen from the surrounding environment. When annealing occurs without vibration, on the anti-vibration stage, larger binary and ternary crystalline alloys form within the coated multi-crystalline layer on the specimen. The use of the anti-vibration stage during high-temperature annealing helps eliminate vibrations, allowing for the formation of a larger and more uniform crystalline layer on the surface of the substrate. Exceeding the melting point may damage the specimen. High-temperature annealing can be performed under vacuum or at ambient conditions, depending on the application requirements.

Accordingly, as seen in FIG. 7, a subprocess of the method of the present invention begins by providing a hot plate and an anti-vibration table, wherein the hot plate is placed onto the anti-vibration table. The anti-vibration table eliminates external vibrations from the surrounding environment. Further, the subprocess continues by placing the silver-gallium film and the treatable apparatus onto the hot plate, followed by holding still the silver-gallium film and the treatable apparatus with the anti-vibration table. When annealing occurs without vibration, on the anti-vibration stage, larger binary and ternary crystalline alloys form within the coated multi-crystalline layer on the specimen. Accordingly, the subprocess continues by annealing the silver-gallium film and the treatable apparatus with the hot plate during Step C. During high-temperature annealing, the binary alloys melt, facilitating the formation of ternary alloys. Some of the excess gallium reacts with oxygen to form a gallium oxide (Ga₂O₃) film, as shown in FIG. 5 and FIG. 8. The gallium oxide forms primarily on the surface of the Ag₂Ga_yM crystalline film, with the film thickness varying based on the amount of excess gallium.

According to the method of the present invention, at least one physical property of the protective intimate coating is modified by adjusting at least one of process parameters during Steps B through D, wherein the process parameter is selected from the group consisting of: an atomic ratio between silver and gallium, a thickness of the silver-gallium film, a kind of deposition method of the silver-gallium film during Step B, an annealing duration, an annealing temperature, a sanding duration, a sanding grit, and a combination thereof.

The effect of the process parameters is described below.

According to the method of the present invention, ternary alloys Ag₂Ga_yM are formed when Ag_xGa is applied to a third metal (M). This process results in a chemical reaction where Ag₂Ga and excess Ga combine with M to form a ternary crystalline structure. For example, when Ag_xGa is applied to copper, the following reaction occurs:

where n=2

This reaction indicates that for copper, the optimal value of x in Ag_xGa is 0.67 (⅔), ensuring the formation of Ag₂Ga₃Cu. The invention further provides predictions for other metals, such as n=3 for iron (yielding Ag₂Ga₄Fe) and n=4 for chromium. Values of x and y are all listed in FIG. 3. Also, the Ag to Ga weight ratio is listed in FIG. 3.

Key Factors for Optimal Coating Quality

The quality of the Ag₂Ga intimate coating depends on several critical factors, including:

• • 1. Coating Thickness: Thinner layers allow for better control of the film's transparency when applied to transparent substrates.
  • 2. Annealing Temperature and Time: Lower annealing temperatures produce more uniform but smaller crystals, while higher temperatures yield larger crystals, improving durability and resistance to harsh conditions.
  • 3. Post-Annealing Brushing or Polishing: This step enhances the smoothness and uniformity of the coating which also affects the coating color.
  • 4. Substrate Type: The choice of metal or non-metal substrate affects the adherence and stability of the coating.

During high-temperature annealing, a protective gallium oxide layer may form on the surface, providing additional protection against oxidation.

Controlling the Properties of the Coating

The invention also allows for precise control over the properties of the Ag_xGa intimate coating by adjusting parameters such as the atomic ratio (x), annealing time, temperature, and post-annealing brushing. This enables the production of coatings with varying colors—from blue-black tones at lower x values to yellow-white hues at higher x values—allowing for aesthetic customization in applications like jewelry and reflective surfaces.

Following are some examples of ternary alloys formed according to the method of the present invention.

As a first example, wherein the specific material is copper, and wherein a chemical composition of the silver-gallium film is Ag_0.67Ga, and wherein an annealing temperature during step (C) is 2000 degrees Fahrenheit (° F.), then a chemical composition of the ternary alloy is Ag₂Ga₃Cu.

In one embodiment, the process described here has been applied to copper sheets and wires, resulting in several Ag₂Ga₃Cu coated copper sheets and wires with different colors and patterns, suitable for use in jewelry. From observations and additional studies, the following qualitative rules have been established for controlling the color of Ag₂Ga₃Cu coatings on copper films:

• • 1. Effect of Silver-to-Gallium Ratio (x):
    • Lowering the ratio x in Ag_xGa results in colors within the blue to black spectrum.
    • Increasing the ratio x shifts the colors towards the yellow to white spectrum, making it suitable for producing lighter-colored coatings.
  • 2. Impact of Annealing Temperature and Duration:
    • Lower temperatures and shorter annealing times produce colors on the white to-yellow end of the spectrum.
    • Higher temperatures and longer annealing durations result in darker yellow, then brown, and ultimately a graphite-like color as the annealing time increases.
  • 3. Influence of Brushing Techniques:
    • Sand brushing the surface after annealing typically yields a yellowish color, independent of the annealing process and ratio of x.
    • Brushing with a metal brush results in a darker surface, producing a graphite-like appearance.
    • During soft brushing, an interesting phenomenon was observed: particles removed during brushing tend to redeposit on the specimen's surface and adhere atomically. This was confirmed by weighing the samples before and after brushing, with no significant weight change (within a ±0.001 gram resolution), even after extended brushing. This suggests that the particles removed during brushing interact with the film and recombine with the surface crystals.
  • 4. Color Variations by Brushing Method:
    • Sand brushing tends to yield a more yellowish finish on the surface.
    • Brushing with a metal brush results in a graphite-like appearance, adding to the aesthetic versatility of the coating.

These findings demonstrate the present invention's ability to precisely control the color and surface appearance of Ag₂Ga₃Cu coated copper films by adjusting key parameters, making the invention particularly valuable for creating custom jewelry with a range of color tones and finishes. The control over color variation and surface properties through annealing and brushing techniques provides a versatile approach to jewelry manufacturing.

As a second example, wherein the specific material is iron, and wherein a chemical composition of the silver-gallium film is Ag_0.5Ga, and wherein an annealing temperature during Step C is up to 2800° F., then a chemical composition of the ternary alloy is Ag₂Ga₄Fe.

In reference to FIG. 9, the table illustrates that, where the metal coated with the ternary alloys, significant improvements in current density limit, malleability and resistance to oxidation are observed, when compared with non-coated metal.

As a third example, wherein the specific material is chromium, and wherein a chemical composition of the silver-gallium film is Ag_0.4Ga, and wherein an annealing temperature during Step C is up to 3400° F., then a chemical composition of the ternary alloy is Ag₂Ga₅Cr.

As a fourth example, wherein the specific material is cobalt, and wherein a chemical composition of the silver-gallium film is Ag_0.5Ga, and wherein an annealing temperature during Step C is up to 2700° F., then a chemical composition of the ternary alloy is Ag₂Ga₄Co.

As a fifth example, wherein the specific material is nickel, and wherein a chemical composition of the silver-gallium film is Ag_0.4Ga, and wherein an annealing temperature during Step C is up to 2700° F., then a chemical composition of the ternary alloy is Ag₂Ga₅Ni.

As a sixth example, wherein the specific material is tungsten, and wherein a chemical composition of the silver-gallium film is Ag_0.57Ga, and wherein an annealing temperature during Step C is up to 6000° F., then a chemical composition of the ternary alloy is Ag₂Ga_3.5W.

Following are some applications of ternary alloys formed according to the method of the present invention.

An application of Ag_xGa is being used a conductive adhesive to bond two electrical conductors. The Ag_xGa mixture is first melted at an elevated temperature, then applied to both conductors. The device is locally annealed and cooled to create a strong electrical bond. This application is particularly useful in wire bonding for electronics, improving connections between copper wires and copper pads on circuit boards, especially when both are made of Ag₂Ga₃Cu coated coppers.

Another application of the present invention is application of Ag₂Ga₃Cu coated copper sheets or AgGa_yAl coated aluminum sheets to supply electrical power to electric vehicles (EVs) from the road. The EVs receive power through one or more contact points attached to the EVs, which are also coated with Ag_xGa and maintain contact with the Ag₂Ga_yM coated sheets. The road is powered by nearby energy sources (e.g. solar cells, wind turbine), which connect to the Ag₂Ga_yM electrical grids embedded in the road. The Ag_xGa intimate coating is electrically conductive, and one can turn any surface into an electrically conductive surface. For example, asphalt and concrete surfaces on the street can be coated with a layer of Ag_xGa mixture to provide electrical contact for future EVs, where the EV would receive the electrical power from the street through one or multiple contact points attached to the car that are also coated with Ag_xGa and are in contact with the surface of the street that is also coated with the Ag_xGa. The electrodes will provide a perfect connection between the Vehicle and the street which is connected to the electrical network of the surrounding road. This will eliminate the need for batteries in EVs in the future, where they will receive electricity from the street, and be powered up.

In an alternative embodiment, an application of Ag_xGa binary alloy is coating aluminum foil with Ag_xGa. Even though there is no binary alloy GaAl, coating Aluminum (Al) with Ag_xGa can significantly improve its mechanical and electrical properties, offering the potential for diverse applications across multiple industries. These improvements make Ag_xGa coated aluminum ideal for use in areas requiring increased conductivity, durability, mechanical strength, and surface protection.

In another alternate embodiment, Ag_xGa can be easily coated to many different non-conductive materials including but not limited to, glass, plastic, polymer, Teflon, wood, paper etc., where the Ag_xGa intimate coating provides electrical conductivity, decorative properties, improved reflectivity, and color variation. For example, coating the surface of several glass slides with intimate Ag_0.9Ga coating and sand polishing the surface made an extremely well reflective surface on glass. Thus, a binary alloy of Ag_xGa, may be used as a coating that adheres strongly to non-metals without interacting chemically, forming a durable, well-bonded coating.

For example, an application of Ag_xGa intimate coating is to coat non-conductive, transparent substrates (e.g., plastic, glass) to make them conductive while maintaining transparency. By applying thinner layers of Ag_xGa on transparent materials (e.g., glass, polymer), semi-transparent conductive coatings can be produced, suitable for solar cell technology. An annealing step is required to enhance the layer's transparency. The Ag_xGa layer is annealed at up to 400° C. on a hotplate, causing Ag₂Ga nano and micro crystals to form interconnected metallic islands, which provide conductivity, while transparent gallium oxide islands form around them. This combination creates a semi-transparent conductive film that is approximately times more conductive than Indium Tin Oxide (ITO) films currently used in the industry

Another application of Ag_xGa is to coat glass substrates to create conductive, semi-transparent glass products. Ag_xGa (x=0.5) has been applied to several glass slides, which are then immersed in dilute Hydrochloric Acid (HCl 1N) for a few minutes. The HCl selectively removes excess gallium, leaving a transparent conductive Ag₂Ga nanowire network with 86% of the conductivity of a similar silver film. To that end, the film is immersed in the HCl bath and air-dried, resulting in a semi-transparent nanowire network. For added durability, drying can be performed inside a critical point dryer to prevent film damage.

Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.