Process of treating a surface of a vehicle wheel and vehicle wheel produced by such process

Abstract

A method of surface treating a vehicle wheel, wherein a vehicle wheel having a surface is first provided. The surface of the wheel is pretreated to clean the surface from contaminants and passivated to prepare the surface for coating. A coating is applied onto the surface of the wheel, wherein the multi- functional engineered ceramic coating is formed from a sol-gel process. The coating is cured to form a hardened coated layer on the surface of the wheel.

Description

TITLEPROCESS OF TREATING A SURFACE OF A VEHICLE WHEEL AND VEHICLE WHEEL PRODUCED BY SUCH PROCESSRELATED APPLICATIONSThis application claims priority to United States Provisional Application No. 63 / 694,958 filed under 35 U.S.C. § 111(b) on September 16, 2024, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION

[0001] The present invention relates in general to a process of treating the surface of a wheel, such as a commercial vehicle wheel, to enhance the durability, scratch resistance, ease of cleaning, and corrosion resistance of the surface of the vehicle wheel.

[0002] Wheels for automotive and commercial vehicles are produced and formed from many different types of manufacturing methods such as stamping, forging, fabrication, and casting. Wheels can generally be described as having an inner centrally located disc and an outer annular rim. The disc includes a mounting portion for attachment to the vehicle. The mounting portion usually includes a plurality of bolt holes for receiving lug bolts and lug nuts for fastening the wheel to the vehicle. The annular shaped rim is shaped to receive a tire mounted thereon. The wheels may be formed as a one-piece single unit or made from multiple components which are then attached together. For example, a wheel disc may be attached to an annular shaped rim such as by welding, adhesives, and mechanical fastening. Additionally, the wheels maybe made from many different materials such as aluminum, steel, stainless steel, titanium, and alloys thereof

[0003] Many commercial vehicle wheels are made of aluminum or aluminum alloys which include magnesium, nickel and titanium. These commercial wheels are commonly forged into a single one-piece wheel. Forged wheels are generally made from compressing a billet or solid piece of material under high heat and pressure using a forging press to form the desired shape of the wheel. The forged wheel may then be heat treated and / or machined into a final shape.

[0004] After the forging process is complete, the aluminum wheel usually undergoes a finishing or surface treatment process to enhance the durability and corrosion resistance of desired surfaces of wheel. For example, the outboard or inboard facing surfaces of the wheel disc center may undergo such finishing or surface treatment processes. One such surface treatment process is described in U.S. Patent No. 6,440,290. The disclosed method includes applying a chemical brightening composition, deoxidizing the surface of the wheel in a nitric acid-based bath, forming a porous oxide, and then spraying a poly siloxane-based film or coating to the porous oxide. While this surface treatment may be somewhat effective, it is desirable to have an improved wheel surface treatment process that increases the durability and corrosion resistance for wheel surfaces.SUMMARY OF THE INVENTION

[0005] The present invention relates to an improved process of treating a surface of a vehicle wheel and vehicle wheel produced by such a process as illustrated and / or described herein.

[0006] According to one embodiment, the method or treating a surface of a vehicle wheel may comprise, individually and / or in combination, one or more of the following steps, features, elements, and / or advantages: (a) providing a vehicle wheel having a surface; (b) pretreating the surface of the wheel to clean the surface from contaminants; (c) applying a coating onto the surface of the wheel, wherein the coating was formed by a sol-gel process; and (d) curing the coating to form a hardened coated layer on the surface of the wheel.

[0007] According to this method, the vehicle wheel is a vehicle wheel made of one of aluminum, aluminum alloys or steel, preferably a forged aluminum wheel, a cast aluminum wheel or a steel vehicle wheel.

[0008] According to this method, step (b) includes degreasing the surface to remove grease and other contamination from the surface.

[0009] According to this method, step (b) includes conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface.

[0010] According to this method, step (b) includes rinsing the surface with a deionized fluid.

[0011] According to this method, step (b) includes conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface.

[0012] According to this method, subsequently to step (b), drying the surface by applying heat.

[0013] According to this method, in step (c), first and second coatings are applied to the surface.

[0014] According to this method, the first and second coatings are made of the same components.

[0015] According to this method, the first and second coatings are nearly identical in composition.

[0016] According to this method, the first coating is substantially thinner in thickness than the second coating.

[0017] According to this method, the first coating has a thickness in the range of between 0.1 to about 5 micrometers.

[0018] According to this method, the second coating has a thickness in the range of between 5 to about 25 micrometers.

[0019] According to this method, after the application of the first coating, waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate.

[0020] According to another embodiment, the method or treating a surface of a vehicle wheel may comprise, individually and / or in combination, one or more of the following steps, features, elements, and / or advantages: (a) providing a vehicle wheel having a surface; (b) pre-treating the surface of the wheel to clean the surface from contaminants; (c) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersedtherein and was formed by a sol-gel process; (d) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate; (e) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and curing the first and second coatings to form a hardened coated layer on the surface of the wheel.

[0021] According to this method, step (b) includes the steps of: (1) degreasing the surface to remove grease and other contamination from the surface; (2) conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface; and (3) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface.

[0022] According to this method, the first coating has a thickness in the range of between 0.1 to about 5 micrometers.

[0023] According to this method, the second coating has a thickness in the range of between 5 to about 25 micrometers.

[0024] According to another embodiment, the method or treating a surface of a vehicle wheel may comprise, individually and / or in combination, one or more of the following steps, features, elements, and / or advantages: (a) providing a vehicle wheel having a surface; (b) polishing the surface with abrasive polish to obtain a relatively smooth finish on the surface; (c) pretreating the surface of the wheel to clean the surface from contaminants and prepare the surface a coating process, wherein the pre-treating process includes the steps of: (1) degreasing the surface to remove grease and other contamination from the surface; (2) conducting an acid pickling process on thesurface to remove impurities and corrosion products from the surface; (3) rinsing the surface with a deionized fluid; and (4) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface; (d) drying the surface by applying heat; (e) subsequently to step (d), cooling the surface; (f) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersed therein and, wherein the first coating was formed by a sol-gel process; (g) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate; (h) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and (i) curing the first and second coatings by subjecting the first and second coatings to heat to form a hardened coated layer on the surface of the wheel; and (j) subsequently to step (i), cooling the hardened coated layer.

[0025] According to another embodiment a vehicle wheel is produced having a surface treated by one of the methods described herein.

[0026] According to this embodiment, the vehicle wheel is a vehicle wheel made of one of aluminum, aluminum alloys or steel, preferably a forged aluminum wheel, a cast aluminum wheel or a steel vehicle wheel.

[0027] According to another embodiment, the method or treating a surface of a vehicle wheel may comprise, individually and / or in combination, one or more of the following steps, features, elements, and / or advantages: (a) providing a commercial forged aluminum vehicle wheel having a surface; (b) polishing the surface with abrasive polish to obtain a relatively smooth finish on the surface; (c) pre-treating the surface of the wheel to clean the surfacefrom contaminants and prepare the surface a coating process, wherein the pretreating process includes the steps of: (1) degreasing the surface to remove grease and other contamination from the surface; (2) conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface; (3) rinsing the surface with a deionized fluid; and (4) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface; (d) drying the surface by applying heat; (e) subsequently to step (d), cooling the surface; (f) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersed therein and, wherein the first coating was formed by a sol-gel process; (g) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate; (h) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and (i) curing the first and second coatings by subjecting the first and second coatings to heat to form a hardened coated layer on the surface of the wheel; and (j) subsequently to step (i), cooling the hardened coated layer.

[0028] Further provided is a coating composition comprising a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl- , methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt%. The coating composition comprises a solvent present in an amount of about 0.1 wt% to about 85 wt%. The weight percentages are based on total uncured composition weight and the combined weight percent of the composition is 100 wt%.

[0029] In certain embodiments, the hydrolysable silane comprises an epoxyfunctional silane selected from y-glycidoxypropyltrimethoxysilane, y- glycidoxypropyltriethoxysilane, or mixtures thereof

[0030] In certain embodiments, the coating composition further comprises a plurality of inorganic nanoparticles having an average particle size of about 2 nm to about 50 nm. The inorganic nanoparticles may be selected from SiCh, ZrCh, TiCh, MgO, CeCh, boron oxide, iron oxide, alumina, and boehmite alumina, and may be present in an amount of about 0.5 wt% to about 20 wt%.

[0031] In certain embodiments, the coating composition further comprises a functional additive present in an amount of about 0.1 wt% to about 35 wt%.

[0032] In certain embodiments, the coating composition further comprises an organic polymeric resin present in an amount of about 0.1 wt% to about 60 wt%.

[0033] In certain embodiments, the coating composition further comprises one or more additives selected from cross-linking agents, curing agents, and catalysts, present in an amount of about 0.1 wt% to about 25 wt%.

[0034] In certain embodiments, the coating composition comprising the one or more functional additives further comprises an organic polymeric resin present in an amount of about 0.1 wt% to about 60 wt%.

[0035] In certain embodiments, the composition comprising the one or more functional additives and the organic polymeric resin further comprises a functional additive present in an amount of about 0.1 wt% to about 35 wt%.

[0036] In certain embodiments, the organic polymeric resin comprises a polyester-urethane resin having a molecular weight of about 800 grams per mole to about 3,000 grams per mole.

[0037] In certain embodiments, the molar ratio of silicon atoms in the hydrolysable silane to carbon atoms in the organic polymeric resin is from about 0.5: 1 to about 5: 1.

[0038] Further provided is a method of forming a corrosion-resistant coating on a metallic substrate, the method comprising: preparing a composition comprising (1) a hydrolysable silane selected from the group consisting of alkyl- , aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt%; and (2) a solvent in an amount of about 0.1 wt% to about 85 wt%, wherein the combined weight percent of the composition is 100 wt%. The method further comprises applying the composition to at least a portion of the metallic substrate to form a wet film, and curing the wet film at a temperature of about 50°C to about 250°C and / or by ultraviolet irradiation to obtain a dry film having a thickness of about 0.1 pm to about 100 pm.

[0039] In certain embodiments, the curing step comprises curing the wet film at a temperature of about 50°C to about 250°C for a duration of about 5 minutes to about 120 minutes.

[0040] In certain embodiments, the metallic substrate comprises an aluminum wheel.

[0041] Further provided is a coating composition comprising a cross-linked, inorganic-organic hybrid network formed from curing an uncured composition comprising (i) a hydrolysable silane selected from the group consisting of alkyl- , aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt% of the uncured composition; and (ii) a solvent present in an amount of about 0.1 wt% to about 85 wt% of the uncured composition.

[0042] Various aspects of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiments, when read in light of the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Fig. 1 is a front perspective view of an example of a vehicle wheel having a front face surface which is suitable for being treated by a treatment process, in accordance with the present invention.

[0044] Fig. 2 is an enlarged cross-section of a portion of the front face surface of the vehicle wheel of Fig. 1.

[0045] Fig. 3 is a flowchart describing a basic general wheel treatment process for the surface of a wheel such as the vehicle wheel of Fig. 1, in accordance with one embodiment of the present invention.

[0046] Fig. 4 is a flowchart describing another embodiment of a wheel treatment process for the surface of a wheel such as the vehicle wheel of Fig. 1.

[0047] Fig. 5 is a flowchart describing yet another embodiment of a wheel treatment process for the surface of a wheel such as the vehicle wheel of Fig. 1.

[0048] Fig. 6 is a schematic representation of a chemical composition for a surface treatment coating applied to a surface of a wheel, such as the vehicle wheel of Fig. 1.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] The following description of technology is merely exemplary in nature of the subject matter, manufacture and use of one or more inventions, and is not intended to limit the scope, application, or uses of any specific invention claimed in this application or in such other applications as may be filed claiming priority to this application, or patents issuing therefrom. Regarding methods disclosed, the order of the steps presented is exemplary in nature, and thus, the order of the steps can be different in various embodiments, including where certain steps can be simultaneously performed. “A” and “an” as used herein indicate “at least one” of the item is present; a plurality of such items may be present, when possible. Except where otherwise expressly indicated, all numerical quantities in this description are to be understood as modified by the word “about” and all geometric and spatial descriptors are to be understood as modified by the word “substantially” in describing the broadest scope of the technology. “About” or “substantially” when applied to numerical values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by “about” and / or “substantially” is not otherwise understood in the art with this ordinary meaning,then “about” and / or “substantially” as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters.

[0050] Although the open-ended term “comprising,” as a synonym of non- restrictive terms such as including, containing, or having, is used herein to describe and claim embodiments of the present technology, embodiments may alternatively be described using more limiting terms such as “consisting of’ or “consisting essentially of’. Thus, for any given embodiment reciting materials, components, or process steps, the present technology also specifically includes embodiments consisting of, or consisting essentially of, such materials, components, or process steps excluding additional materials, components or processes (for consisting of) and excluding additional materials, components or processes affecting the significant properties of the embodiment (for consisting essentially of), even though such additional materials, components or processes are not explicitly recited in this application. For example, recitation of a composition or process reciting elements A, B and C specifically envisions embodiments consisting of, and consisting essentially of, A, B and C, excluding an element D that may be recited in the art, even though element D is not explicitly described as being excluded herein.

[0051] As referred to herein, all compositional percentages are by weight of the total composition, unless otherwise specified. Disclosures of ranges are, unless otherwise specified, inclusive of endpoints and include all distinct values and further divided ranges within the entire range. Thus, for example, a range of “from A to B” or “from about A to about B” is inclusive of A and of B. Disclosure of values and ranges of values for specific parameters (such as amounts, weight percentages, etc.) are not exclusive of other values and ranges of values useful herein. It is envisioned that two or more specific exemplifiedvalues for a given parameter may define endpoints for a range of values that may be claimed for the parameter. For example, if Parameter X is exemplified herein to have value A and also exemplified to have value Z, it is envisioned that Parameter X may have a range of values from about A to about Z. 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 combinations of ranges for the value that might be claimed using endpoints of the disclosed ranges. For example, if Parameter X is exemplified herein to have values in the range of 1-10, or 2-9, or 3-8, it is also envisioned that Parameter X may have other ranges of values including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3- 10, 3-9, and so on.

[0052] Referring now to the drawings, there is illustrated in Fig. 1 a commercial vehicle wheel, indicated generally at 10. As will be discussed in detail herein, the wheel 10 is one such example of a wheel which is suitable for receiving a wheel treatment process, in accordance with the present invention. For example, the wheel treatment process discussed with respect to Figs. 3, 4, and 5 below may be utilized for the wheel 10. However, it should be understood that the treatment processes described herein may be applied to any type of vehicle wheel and is not meant to be limited to the wheel 10 described in Fig. 1. Thus, the wheel 10 will be described and discussed below as merely one example of a vehicle wheel ideally suited to be used with the treatment processes of the present invention and it should be appreciated that the invention can be used in conjunction with other types of vehicle wheel constructions.

[0053] The wheel 10 generally incudes an inner wheel disc, indicated generally at 12, and an outer annular rim, indicated generally at 14. Thecombination of the disc 12 and the rim 14 defines a wheel axis X for the wheel 10. The rim 14 can have any suitable annular shape for receiving and supporting a tire (not shown). The rim 14 defines an outer tire well, indicated generally at 16, preferably having a continuous annular shape relative to the wheel axis X for accommodating a vehicle tire (not shown) mounted thereon. It should be appreciated that the rim 14 can have any desired diameter and / or shape.

[0054] The disc 12 defines a hub 20 located centrally within the disc 12 about the wheel axis X. The hub 20 includes a centrally located hub hole 22. The hub hole 22 extends along the wheel axis X. The hub hole 22 may accommodate a portion of the axle (not shown) of the vehicle upon which the wheel 10 is mounted. The hub hole 22 may have any suitable diameter. A plurality of lug bolt receiving holes 24 are formed in the hub 20 and are spaced circumferentially around the hub hole 22 and the wheel axis X. The lug bolt receiving holes 24 are preferably spaced circumferentially about the hub hole 22 equidistant from one another. In the illustrated embodiment, the hub 20 includes ten lug bolt receiving holes 24. Of course, the number and / or location of the lug bolt receiving holes 24 may be other than illustrated if so desired. The lug bolt receiving holes 24 receive lug bolts (not shown) for securing the wheel 10 with lug nuts (not shown) on the axle of an associated vehicle. The disc 12 may further include a plurality of vent openings 26 formed therein. The vent openings 26 may have any suitable shape and may be positioned anywhere within the disc 12. Of course, the wheel 10 may also be formed without vent openings 26 if so desired.

[0055] The disc 12 further defines a front face or front surface 30 and a rear surface (not shown in Fig. 1). The front surface 30 is located on theoutboard side of the wheel 10 when mounted on a vehicle. The rear surface faces the inboard side of the wheel 10 when mounted on a vehicle. As will be discussed below, the surface treatment process of the present invention may be applied to any of the surfaces of the wheel 10 but are ideally suited surfaces exposed the environment, such as the front face 30, the rear face, and any exposed surfaces of the rim 14. Of course, any surface of the wheel 10 may include the surface treatment for corrosion resistant properties.

[0056] The wheel 10 may be a commercial vehicle wheel ideally suited for mounting on commercial vehicles. Examples of commercial vehicles include light and heavy-duty trucks, trailers, construction and agricultural vehicles. The wheel 10 shown and described in Fig. 1 may be made of aluminum or an aluminum alloy. For example, the wheel 10 may be made of an aluminum alloy including magnesium, nickel and / or titanium. Of course, it should be understood that the wheel 10 may be made of any suitable material such as steel, stainless steel, titanium, magnesium, various alloys, composites, or carbon fiber. Also, the wheel 10 may be a one piece wheel, such as a forged aluminum wheel or a cast aluminum wheel or a fabricated wheel comprised of two or more pieces which are joined together by suitable means.

[0057] The wheel 10 may be made by any suitable manufacturing process. For example, the wheel 10 may be forged into a single one-piece aluminum wheel. The forging process generally includes compressing a billet or solid piece of material under high heat and pressure using a forging press to form the desired shape of the wheel 10. Surfaces of the wheel 10 manufactured in a forging process are well suited for receiving the wheel treatment processes described herein. However, it should be understood that the surface treatment processes of the present invention may be used on wheels not manufactured bya forging process or made with materials other than aluminum. Such examples include wheels that are cast, stamped, rolled or flow formed. Generally, cast wheels do not polish to the same shine and luster as forged wheels both due to the alloy composition as well as the inherent porosity in casting. However, the surface treatment processes discussed herein may be applied in addition to the typical coating process for cast wheels or, alternatively, be used in place of the typical coating process used for treating cast wheels. The surface treatment process of the present invention may also be used on steel or stainless steel wheels which conventionally have a liquid applied coating thereon. The surface treatment process may be applied on top of the liquid applied coating or in place of the conventional liquid applied coating.

[0058] Referring to Fig. 2, there is shown an extremely enlarged crosssection of a portion of the front surface 30 of the disc 12 of the wheel 10 which has been surface treated in accordance with the present invention, as will be explained in detail below. After the surface treatment, a hardened coating 40 is formed on the aluminum substrate at the front surface 30 of the wheel 10. In one example with respect to the process described in Fig. 5, the coating 40 has a thickness t of about 16 microns or micrometers. Of course, the thickness t can be any desired thickness. In a preferred embodiment, only the coating 40 is formed on the desired surface, such as the front surface 30, after the surface treatment of the wheel 10. However, other finishes or coatings (not shown) may be introduced between the coating 40 and the front surface 30 such that the coating 40 is formed above such finishes or coatings. Optionally, other finishes or coatings may be applied on top of a surface 42 of the coating 40.

[0059] Referring now to Fig. 3, there is illustrated a flowchart of a wheel treatment process, indicated generally at 50. The wheel treatment process 50 isdescribed herein as an overview and defined in broad general process steps for a wheel treatment process which is suitable for a surface of a wheel, such as for example, the front surface 30 of the wheel 10. As noted above, the wheel treatment process 50 will be described with respect to treating the front surface 30 of the wheel 10 but can also be used for treating any surface of the wheel 10 or other wheels. For example, it may generally be desirable to treat all of the surfaces of the wheel 10 with the exception of the tire well 16. For other applications, it may be desirable to only treat the visible surfaces of the wheel 10, such as the front face surface 30 only. Other types of wheels, for example a dual wheel assembly generally having two wheels joined together at their respective front faces, it may be desirable to treat both sides of disc 12. For simplicity in this description, the wheel treatment processes described below will be referred to treating the surface 30. Note that more detailed wheel treatment processes are described below with respect to Figs. 4 and 5.

[0060] As shown in Fig. 3, the wheel treatment process 50 generally includes the steps of polish, indicated by the box 52, pre-treatment, indicated by the box 54, surface treatment, indicated by the box 56, and cure, indicated by the box 58.

[0061] The step of polishing 52 is an optional step in the wheel treatment process 50 that is common in the industry and which is performed after the wheel 10 is manufactured. For wheels that are manufactured in a forging procedure, a polishing procedure 52 is usually performed. The step of polishing 52 helps to create a mirror like shiny finish on the surface 30. However, the polishing process 52 will generally not retain a luster and shine without further coatings or surface treatments. Thus, the step of surface treatment 56 is a preferred subsequent step and retains this luster and shine aswell as providing superior corrosion resistance along with other benefits as disclosed below.

[0062] The step of polishing 52 can be performed by a variety of suitable methods. Polishing 52 may be performed manually or by automated machinery, such as for example, by robotic devices. In general, the step of polishing 52 includes brushing or scrubbing a slightly abrasive liquid finishing polish across the surface 30 until a desired smoothness is obtained. Multiple levels of brushing and / or different abrasive or grit finishing polishes may be used. The smoothness of the surface 30 generally refers to the evenness or roughness of the surface 30.

[0063] As stated above, the polishing step 52 is an optional procedure and may be eliminated altogether such that wheel 10 advances to the step of pretreatment after manufacture. Alternatively, other cleaning or surface preparations may be performed instead of the polishing step 52. For example, a heat treating or annealing process may provide a bright annealed finish for the surface 30 having a desired smoothness. Brush finish processes or bright machine finishing processes may be utilized as well providing a desired level of smoothness to the surface 30.

[0064] The surface 30 of the wheel 10 preferably undergoes a pre-treatment step 54. The pre-treatment process 54 essentially cleans the surface 30 and prepares the surface 30 to more easily and better receive the surface treatment 56. The pre-treatment process 54 helps to ensure that the surface 30 is chemically and electrically prepared to help maximize the adhesion of a coating applied in the surface treatment process 56, as will be described below.

[0065] Many different procedures and processes can be undertaken during the pre-treatment process 54 to sufficiently prepare the surface 30. Examples include rinsing, degreasing, acid pickling, and passivation. These examples will be described in detail below with respect to the wheel treatment processes of Figs. 4 and 5. It should be understood that any suitable procedure for sufficiently preparing the surface 30 may be utilized. Other examples include chemical brightening, anodizing, and deoxidation. A deoxidation process generally deteriorates and removes the natural oxide layer formed on the surface to help prepare the surface for further surface treatments. This may be desirable because the oxide layer that forms when the surface material, such as aluminum, is exposed to the environment. This oxide layer can interfere with surface treatment processes. Solutions used in deoxidation processes include acid-based solutions, nitric acid, sulfuric acid, chromic acid, ferric sulfate, hydrofluoric acid, sulfuric acid, and phosphoric acid. Laser ablation may also be used. Laser ablation generally uses a powerful laser beam to heat the oxidation until it evaporates.

[0066] After the pre-treatment step 54 is completed, the surface 30 will then preferably undergo a surface treatment process 56. In general terms, the surface treatment process 56 includes applying a film or coating to the recently pre-treated surface 30 to form a hardened coated layer, such as the coating 40 in Fig. 2, on top of the surface 30. This hardened coated layer or coating 40 enhances the durability and corrosion resistance of the surface 30. The coating may be applied by a spraying process. For example, the coating may be first supplied “wet” as a liquid or gel which is then sprayed onto the surface 30.

[0067] The coating can then undergo a curing process 58 to harden the coating to a hardened solid state, such as to form the coating 40. The curing process 58 may be any suitable process which converts the initially supplied“wet” coating material to a solid state. The curing process 58 may be a drying process in which a removal of water or solvent within the wet coating is removed by means of evaporation. Preferably, the curing process 58 is a chemical process in which the coating material toughens or hardens such that the final coating 40 is solid. The curing process 58 may be accomplished by any suitable method. Examples of possible curing processes 58 include room temperature curing, mild heat acceleration curing, heat curing, UV curing light or any combination thereof. As will be discussed in detail below, a preferred coating is a coating material formed from a sol-gel process.

[0068] Referring now to Fig. 4, there is illustrated a flowchart of a wheel treatment process, indicated generally at 60. The wheel treatment process 60 is described herein as a more detailed process compared to the process 50 described above. The wheel treatment process 60 may be executed in any suitable order or combination consistent with the general steps of process 50 and is suitable for application to any surface of a wheel, such as, for example, the front surface 30 of the wheel 10. It should be understood that the steps unique to process 60, relative to process 50, are optional and may be omitted if so desired. It should further be understood that one or more steps of process 60 may be substituted with functional equivalents. The wheel treatment process 60 will be described with respect to treating the front surface 30 of the wheel 10 but should be understood that this process 60 is suitable for any vehicle wheel surface.

[0069] As shown in Fig. 4, the wheel treatment process 60 generally includes the steps of polishing, indicated by the box 62, degreasing, indicated by the box 64, acid pickling, indicated by the box 66, passivation, indicated by the box 68, primer coat, indicated by the box 70, final coat, indicated by thebox 72, and curing, indicated by the box 74. In generally terms, the steps of degreasing 64, acid pickling 66, and passivation 68 are related and generally correspond to the pre-treatment step 54 with respect to the wheel treatment process 50. Also, the steps of primer coating 70 and final coating 72 are related and generally correspond to the surface treatment step 56 with respect to the wheel treatment process 50.

[0070] The step of polishing 62 may be similar to the polishing step 52 described above with respect to the wheel treatment process 50. The step of polishing 62 is an optional step in the wheel treatment process 60 that is common in the industry and which is performed after the wheel 10 is manufactured. The step of polishing 62 helps to create a mirror like shiny finish on the surface 30 and can be performed by a variety of suitable methods. In general, the step of polishing 62 includes brushing or scrubbing a slightly abrasive liquid finishing polish across the surface 30 until a desired smoothness is obtained. The polishing step 62 is an optional procedure and may be eliminated altogether.

[0071] Subsequent to the polishing process 62, the surface 30 preferably undergoes a series of pre-treatment processes such as degreasing 64. The degreasing process generally removes grease, oils, lubricants, debris, contamination, machining particulates, or other foreign matter from the surface 30 of the wheel 10. Any conventional degreasing methods may be utilized in the degreasing process 62. Degreasing agents such as alkaline, solvents and / or aqueous-based cleaners may be immersed or applied onto the surface 30. Volatile solvents such as toluene, acetone, methyl ethyl ketone, ethanol, isopropyl alcohol, and trichloroethylene may be used. Various suitabledegreasing methods include spraying, scrubbing, vapor degreasing, immersion, steam, and high-pressure jet sprays.

[0072] Subsequent to the degreasing process 64, the surface 30 of the wheel 10 may optionally undergo an acid pickling process 66 to further treat the surface 30. In general, an acid pickling process 66 uses acid to remove impurities and corrosion products from the surface 30 of the wheel 10. Any suitable acid solution may be used such as hydrochloric or sulfuric acid which helps to dissolve rust, scale, and other impurities. The acid solution may be applied by any suitable method, such as by spraying or dipping. In some cases, the acid pickling process 66 may remove some material from the surface 30 of the wheel 10.

[0073] Preferably, the surface 30 of the wheel 10 then undergoes a passivation process 68. In general, passivation may include a spray or bath in a chemical solution which triggers a chemical reaction with the metallic material of the wheel 10 to create an outer layer of shield material at the surface 30. Passivation may be referred to as a “controlled oxidation” to describe the intended outcome of the passivation process 68. For example, in the case of a wheel 10 made of aluminum or an aluminum alloy, the passivation process 68 may provide an aluminum oxide coating on the surface 30 which helps prevent further oxidation and corrosion. In some cases, the result of the passivation process 68 is a type of corrosion on the surface 30, since the aluminum material of the wheel 10 reacts to form a hard, relatively inert surface. However, it is the formation of this layer that acts to reduce or minimize any further corrosion on the surface 30. The passivation process 68 may utilize any conventional passivation methods to obtain the desired results. Passivation examples include chromate conversion coating and anodizing. Generally, chromate conversioncoating converts the aluminum surface 30 to an aluminum chromate coating. Anodizing generally is an electrolytic process that forms an oxide layer.

[0074] After the pre-treatment steps 64, 66, and 68 described above, the surface 30 will then preferably undergo a surface treatment process in the form of a first a primer coating 70 and then a second or final coating 72. In general, the primer coating step 70 and the final coating step 72 includes applying coatings to the recently pre-treated surface 30 to form a combined hardened coated layer, such as the coating 40 in Fig. 2, on top of the surface 30. This hardened coated layer or coating 40 enhances the durability and corrosion resistance of the surface 30. The primer coating 70 and the final coating 72 may have the same chemistry or may be made of a material having different ingredients and / or strengths. The primer coating 70 and the final coating 72 may be applied to the surface 30 by any suitable means, such as by submersion or spraying. In a preferred method, the primer coating 70 is sprayed onto the surface 30 at a relatively thin thickness, and the final coating 72 is sprayed on top of the primer coating 70 at a greater thickness. The use of multiple coatings 70 and 72 helps for better adhesion and performance of the finalized hardened coating 40. Preferably, the primer coating 70 is more concentrated such that is relatively thin and then the second or final coating 72 can be applied much thicker to improve the overall performance. It should be understood that a single coating may be used instead of the two primer and final coatings 70 and 72, or that more than two coatings may be applied to the surface 30 to form the coating 40 of the wheel 10. Note that details of potential and preferred coatings used for the primer and final coating 70 and 72 will be described below with respect to the wheel treatment process of Fig. 5, such as for example, the use of coatings formed from a sol-gel process.

[0075] After application of the primer and final coatings 70 and 72, a curing process 74 may be performed to harden the combined coating to a hardened solid state, such as to form the coating 40. The curing process 74 may be similar to the curing process 58 described above.

[0076] In one non-limiting example, the process 60 may comprise passivation 68, followed by application of the primer 70, and then application of the final coating 72. In other non-limiting examples, one or more of these steps may be omitted. For instance, in another non-limiting example, the process 60 may comprise passivation 68 followed only by application of the primer 70. In yet another example, the process 60 may comprise application of the primer 70 followed by application of the final coating 72. In some examples the process 60 may only comprise application of the final coating 72.

[0077] Referring now to Fig. 5, there is illustrated a flowchart of a wheel treatment process, indicated generally at 80. The wheel treatment process 80 is described herein as a more detailed step by step process compared to the processes 50 and 60 described above, and is a preferred method of a wheel treatment process. The wheel treatment process 80 may be executed in any suitable order or combination consistent with the general steps of process 50 and is suitable for application to any surface of a wheel, such as, for example, the front surface 30 of the wheel 10. It should be understood that the steps unique to process 80, relative to process 50, are optional and may be omitted if so desired. It should further be understood that one or more steps of process 60 may be substituted with functional equivalents. The wheel treatment process 80 will be described with respect to treating the front surface 30 of the wheel 10 but should be understood that this process 60 is suitable for any vehicle wheel surface.

[0078] As shown in Fig. 5, an initial step of polishing, indicated by box 82, may be performed after manufacture of the wheel 10. The step of polishing 82 may be similar to the polishing steps 52 and 62 described above with respect to the wheel treatment processes 50 and 60. The step of polishing 82 is an optional step in the wheel treatment process 80 that is common in the industry and which is preferably performed after the wheel 10 is manufactured. The step of polishing 82 helps to create a mirror like shiny finish on the surface 30 and can be performed by a variety of suitable methods. In general, the step of polishing 82 includes brushing or scrubbing a slightly abrasive liquid finishing polish across the surface 30 until a desired smoothness is obtained. It should be understood that the polishing step 82 is an optional procedure and may be eliminated altogether.

[0079] Subsequent to the polishing process 82, the surface 30 preferably undergoes a series of pre-treatment processes, indicated generally by box 84. The pre-treatment process 84 essentially cleans the surface 30 and prepares the surface 30 to more easily and better receive a surface treatment 104 later in the process. The pre-treatment process 84 generally helps to ensure that the surface 30 is chemically and electrically prepared to help maximize the adhesion of a coating applied in the later surface treatment process 104.

[0080] Many different procedures and processes can be undertaken during the pre-treatment process 84 to sufficiently prepare the surface 30 such as those described above. Examples of these other procedures have been described above. In a preferred method, the pre-treatment process 84 includes the steps of degreasing, indicated by the box 86, acid pickling, indicated by the box 88, several steps of deionized rinses, indicated by the boxes 90, 92, 94, and passivation, indicated by the box 96. Of course. It should be understood thatless, more or different processes may be performed under the pre-treatment process 84 if so desired.

[0081] The degreasing process 86 may be similar to the degreasing process 64 described above. The degreasing process 86 generally removes grease, oils, lubricants, debris, contamination, machining particulates, or other foreign matter from the surface 30 of the wheel 10. Any conventional degreasing methods may be utilized in the degreasing process 86. Degreasing agents such as alkaline, solvents and / or aqueous-based cleaners may be immersed or applied onto the surface 30. Volatile solvents such as toluene, acetone, methyl ethyl ketone, methyl alcohol, isopropyl alcohol, and trichloroethylene may be used. Various suitable degreasing methods 86 include spraying, scrubbing, vapor degreasing, immersion, steam, and high-pressure jet sprays.

[0082] Subsequent to the degreasing process 86, the surface 30 of the wheel 10 may optionally undergo an acid pickling process 88 to further treat the surface 30. The acid pickling process 88 may be similar to the acid pickling process 66 described above. Generally, the acid pickling process 88 uses acid to remove impurities and corrosion products from the surface 30 of the wheel 10. Any suitable acid solution may be used such as hydrochloric or sulfuric acid which helps to dissolve rust, scale, and other impurities. The acid solution may be applied by any suitable method, such as by spraying or dipping. In some cases, the acid pickling process 88 may remove some material from the surface 30 of the wheel 10.

[0083] Subsequent to the acid pickling process 88, the surface 30 of the wheel 10 may undergo one or more rinsing operations. Preferably, the rinsing operations involve one or more deionized rinses, as indicated by the boxes 90,92, and 94. Of course, water or any other fluids may be used in the rinsing steps 90, 92, and 94. In a preferred embodiment, deionized water is used. Please note that the industry term “DI” refers to deionized water or other fluids. In general, deionized water, DI water, or demineralized water is water having ions removed. Ions are molecules with a positive or negative electrical charge and in water appear as dissolved mineral salts. These salts are removed from the water or other rinsing fluids to ensure that no residue is left on the surface 30. It should be understood that the rinsing operations 90, 92, and 94 may be performed at anytime before, during, or after other processes during the pretreatment process 84. The rinsing steps 90, 92, and 94 generally help remove any of the products used during the degreasing 86 and acid pickling 88 processes.

[0084] After rinsing, the surface 30 of the wheel 10 may then undergo a passivation process 96. The passivation process 96 may be similar to the passivation process 68 described above. In general, the passivation process 96 includes a spray or bath in a chemical solution which triggers a chemical reaction with the metallic material of the wheel 10 to create an outer layer of shield material at the surface 30. As such, passivation may be referred to as a “controlled oxidation” to describe the intended outcome of the passivation process 96. The passivation process 96 improves the corrosion protection and prevents underfilm corrosion. It also ensures excellent paint adhesion. For example, in the case of a wheel 10 made of aluminum or an aluminum alloy, the passivation process 96 may provide an aluminum oxide coating on the surface 30 which helps prevent further oxidation and corrosion. In some cases, the result of the passivation process 96 is a type of corrosion on the surface 30, since the aluminum material of the wheel 10 reacts to form a hard, relatively inert surface. However, it is the formation of this layer that acts to reduce orminimize any further corrosion on the surface 30. The passivation process 96 may utilize any conventional passivation methods to obtain the desired results. Passivation examples include chroma free, zirconium oxide, titanium oxide, silanes, chromate conversion coating.

[0085] Subsequent to the pre-treatment process 84, the wheel 10 may undergo an optional water drying process, indicated by the box 98. The purpose of the water drying process 98 is used primarily for evaporation. This process 98 is optional and may be refined to minimize cost and maximize the quality and productivity of the pre-treatment process 84. In a preferred process 98, 100 to about 120 °C heated air is introduced for about 10 to about 15 minutes. The wheel 10 then may experience a cooling zone process, indicated by the box 100, to cool the wheel 10 to a desired temperature.

[0086] The pre-treatment process 84, the water drying process 98, and the cooling zone step 100 may be conducted within the same controlled environmental station, such as for example, a closed fluid tank or other type of industrial station. Preferably, the station and equipment are designed to allow for flexibility in the performance of each process step.

[0087] In a preferred embodiment, the wheel 10 may then be physically transferred, as indicated by the step 102, to a surface treatment station for performing a surface treatment process, indicated generally by the box 104. As an example, the surface treatment station may be a positive pressure, controlled relative humidity, and temperature-controlled station having a robot spraying apparatus.

[0088] The surface 30 of the wheel 10 will next undergo a surface treatment process, indicated generally by the box 104. In a preferred embodiment, the surface treatment process 104 includes a first or primer coating step, indicated by the box 106, and a second or final coating step, indicated by the box 110. A flash off process, indicated by the box 108, may be introduced between the primer and final coatings 106 and 110. The flash off process 108 may simply be a waiting period for solvents within the primer coating 106 to evaporate or “flash off’. "Flashing off' is a term or art used to describe when solvents in a liquid product have evaporated after being applied, making the product drier. Of course, the primer coating 106 may not be completely dry after the flash off process 108 but may still exhibit “wet” properties. The flash off period 108 may be any length of time. It has been found that a time period of about one minute has been sufficient. During the flash off period 108, heat may or may not be introduced to the primer coating 106.

[0089] In general, the primer coating step 106 and the final coating step 110 includes applying the coatings to the recently pre-treated surface 30 to form a combined hardened coated layer, such as the coating 40 in Fig. 2. This hardened coated layer or coating 40 may essentially be formed as a ceramic coating and enhances the durability and corrosion resistance of the surface 30. The primer coating 106 and the final coating 110 may be applied to the surface 30 by any suitable means, such as by spraying by a robotic apparatus. Of course, other suitable application techniques may be used instead. The coating 106 and 110 may be applied by a spraying process such that the coatings are in a liquid or gel like state. For example, the primer coating 106 may be first supplied “wet” as a liquid or gel which is then sprayed onto the surface 30. The final coating 110 may also be supplied wet as a liquid or gel and sprayed on top of the primer coating 106.

[0090] It has been found that the use of multiple coatings 106 and 110 helps for better adhesion and performance of the finalized hardened coating 40. In a preferred method, the primer coating 106 is sprayed onto the surface 30 at a relatively thin thickness, and the final coating 110 is sprayed on top of the primer coating 70 at a greater thickness. It has been found that a primer coating 106 having a thickness in the range of between 0.01 to about 5 micrometers (microns), and a final coating 110 having a thickness in the range of between 1 to about 25 micrometers (microns) is satisfactory to form a desired hardened coating layer 40. In a preferred embodiment, the primer coating 106 is more concentrated such that it is relatively thin and then the second or final coating 110 can be applied much thicker to improve the overall performance. However, it should be understood that the thicknesses of either of the coatings 106 and 110 can be applied to form any sufficient thickness.

[0091] The primer coating 106 and the final coating 110 may be made of the same material and have the same chemistry. Alternatively, the coatings 106 and 110 may be made of a differing material having different components and / or strengths. It should be understood that a single coating may be used instead of the two primer and final coatings 106 and 110, or that more than two coatings may be applied to the surface 30 to form the coating 40 of the wheel 10.

[0092] In a preferred embodiment, the primer and final coatings 106 and 110 (as well as the coatings 70 and 72) are produced by a sol-gel process. In general terms, a sol-gel process is a wet chemical method for producing solid materials from small molecules. The sol-gel process involves converting a solution of small molecules into solid materials. This process generallyinvolves the two words: "sol" and "gel". A sol can be defined as a liquid with solid particles dispersed throughout it, or in other words a suspension of small particles in a liquid that will generally not settle out. A gel can be defined as a porous, three-dimensional solid network that surrounds a liquid phase, or in other words a dispersion of liquid throughout a solid matrix. The sol-gel process gradually changes a sol into a gel-like network before converting it into the final product. The sol-gel process may include the steps of the formation of separate colloidal solid particles with nanometer dimensions, and wherein colloidal particles in the solvent join together to form a gel. A sol-gel process can be a chemical route process used to synthesize glassy or ceramic materials at relatively low temperatures, based on wet chemistry processing, that involves the preparation of a sol, the gelation of the sol, and the removal of the liquid existing in fine interconnected channels within the gel. In certain embodiments, the sol-gel process may be carried out at a temperature ranging from about 5 °C to about 150 °C, depending on the specific precursor chemistry and desired reaction kinetics.

[0093] There is illustrated in Fig. 6 an example of a suitable composition, indicated generally at 130, for the coatings 70, 72, 106, and 110. The composition 130 may include a branched 3D network of Si-O-Si, Si-O-Al, Si- O-Zr, Si-O-Ti and other combinations with adjustable porosity, colloidal structure. Additionally, the coating formulation may contain nano particles of metal oxides, catalysts, organo silanes, metal alkoxides, silanol groups, resins, other additives and other functional groups. Preferably, the bond making groups are everywhere in the 3-D structure such that stronger cross-linking during curing occurs, and hence superior physical and chemical resistance is obtained. The elements of the groups 2, 4, 6, 8, 10, 12, 13, 14 of the periodictable may be the elements of the network of composition 130, preferably Si, Zr, Al, Zn, Ti, B, P, and Mo such that the elements provide extra functionalities.

[0094] Preferably, the material for the coatings 70, 72, 106, and 110, has both hydrophobic and oleophobic properties such that the material helps repel both water-based and oil-based stains. The composition 130 also preferably creates a coating 40 having high durability and is easy to clean. The composition 130 may have a more durable, greater shine, and better color characteristic compared to prior art siloxane coatings. Generally, the polishing step 82 creates a relatively shiny surface 30. The coating 40 on top of the polished surface 30 may be transparent such that the shiny nature of the surface 30 is visualized in gloss. If desired, the coating 40 may be tinted with hues of any desirable color including opaque and translucent colors. For example, the coating 40 may have a slight blue hue which may be more attractive compared to the generally yellow tint of prior art siloxane coatings.

[0095] After the surface treatment process 104 is completed, the wheel 10 is transferred, as indicated by the box 112, to a curing step, as indicated by the box 114. This curing process may be similar to the curing process 58 described above. The curing process and associated use of the curing oven 114 may be any suitable process which converts the initially supplied “wet” coating material to a solid state. Preferably, the curing process is a chemical process in which the coating material toughens or hardens such that the final coating 40 is solid. It has been found that a heat curing process within the oven 114 with heated air at about 160 to about 200 °C and heated for about 15 to about 60 minutes is sufficient. In some embodiments, the curing temperature may be as high as 300 °C The wheel 10 then may experience a cooling zone process, indicated by the box 116, to cool the wheel 10 to a desired temperature.

[0096] The wheel 10 is then unloaded, as indicated by the box 118, and transported to an inspection area where a final controlled inspection, indicated by the box 120, may be optionally performed. The inspection process 120 looks for abnormalities to confirm that there are no inadvertent scratches, dust or fingerprints, for example. Lastly, if passed inspection, the wheel 10 is packaged and ready for shipment, as indicated by the box 122.

[0097] Further provided is a coating composition comprising a hydrolysable silane precursor and a solvent. It has been found that a combination, with at least these components, yields a corrosion-resistant coating that is suitable for application to a wide variety of metallic substrates. Applicable metallic substrates include, but not are not limited to: ferrous metals such as iron, carbon steel, and stainless steel; non-ferrous metals such as aluminum, copper, zinc, magnesium, and titanium; and metal alloys such as galvanized steel, brass, bronze, Inconel, and nickel-chromium alloys. The coating composition may be applied to specific metal articles such as automotive components (i.e., aluminum wheels, brake rotors, calipers, chassis components, heat exchangers, radiators, and exterior body panels); aerospace components (i.e., fuselage panels, wing structures, engine housings, and landing gear); industrial equipment (i.e., pipes, valves, flanges, tanks, and structural frames); consumer goods (i.e., appliances, cookware, tools, and electronic enclosures); construction materials (i.e., roofing panels, window and door frames, railings, and fasteners); and energy or infrastructure-related components (i.e., wind turbine fixtures, solar panel frames, electrical transmission towers, pipelines, and storage tanks).

[0098] In certain embodiments, the hydrolysable silane precursor in the coating composition broadly includes di-, tri-, or tetra-alkoxy silanes, as well assiloxanes, containing from one to four hydrolysable groups. These hydrolysable groups may include alkoxy, acyloxy, aminooxy, or halide. Suitable silane precursors include, without limitation, alkyl trialkoxysilanes, aryl trialkoxysilanes, functional trialkoxysilanes, difunctional or bridging silanes, tetraalkoxysilanes, fluoroalkyl silanes, polysiloxanes or silsesquioxanes, and silazanes. Other organosilane, polysiloxane, or silazane compounds, including mixtures and derivatives thereof, may likewise be employed.

[0099] Representative alkyl trialkoxysilanes include methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, n-octyltrimethoxysilane, dodecyltrimethoxysilane, and n-octadecyltrimethoxysilane or their corresponding triethoxysilane analogs, as well as hexyltrimethoxysilane, isooctyltriethoxysilane, and cyclohexyltrimethoxy silane. Representative aryl trialkoxy silanes include phenyltriethoxysilane, tolyltriethoxysilane, xylyltriethoxysilane, and (4- trifluoromethylphenyl)triethoxysilane, as well as naphthyltriethoxysilane and biphenyltrimethoxy silane. Suitable functional trialkoxy silanes include both trimethoxy- and triethoxy- substituted silanes, such as y- glycidoxypropyltrimethoxysilane (GPTMS) and y- glycidoxypropyltriethoxysilane, y-glycidoxyethyltrimethoxysilane and y- glycidoxyethyltriethoxysilane, y-aminopropyltrimethoxysilane and y- aminopropyltriethoxysilane (APTES), N-(2-aminoethyl)-3- aminopropyltrimethoxy silane and N-(2-aminoethyl)-3- aminopropyltriethoxysilane, vinyltrimethoxysilane (VTMS) and vinyltriethoxysilane, allyltrimethoxysilane and allyltriethoxysilane, mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane, methacryloxypropyltrimethoxysilane (MEMO) andmethacryloxypropyltriethoxysilane, isocyanatopropyltrimethoxysilane and isocyanatopropyltriethoxysilane, as well as ureidopropyltrimethoxysilane and ureidopropyltriethoxysilane, epoxycyclohexylethyltrimethoxysilane, chloropropyltrimethoxysilane, thiocyanatopropyltriethoxysilane, and sulfonylpropyltriethoxy silane. Examples of difunctional or bridging silanes include bis(triethoxysilyl)ethane, bis(triethoxysilyl)propane, and bis(3 - triethoxysilylpropyl)tetrasulfide (TESPT), as well as bis(triethoxysilyl)hexane and bis(trimethoxysilyl)benzene, bis(3 -(trialkoxysilyl)propyl)sulfone, bis(trialkoxysilylalkyl)carbonate, and bis(3 -(trialkoxysilyl)propyl)succinimide. Suitable tetraalkoxy silanes include tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), and tetrapropyl orthosilicate, as well as tetrabutyl orthosilicate. Fluoroalkyl silanes may include tridecafluoro-( 1,1,2, 2-tetrahydro- octyl)-triethoxysilane and heptadecafluoro-decyltrimethoxysilane, as well as perfluorooctyltriethoxy silane and nonafluorohexyltrimethoxy silane. Suitable polysiloxanes and silsesquioxanes include methyl-hydrogen polysiloxane, polydimethylsiloxane (PDMS) and polyhedral oligomeric silsesquioxanes (POSS), such as heptaisobutyl POSS and vinyl-functionalized POSS. Representative silazanes include hexamethyldisilazane (HMDS), divinyltetramethyldisilazane (DVTMDS), and octamethyltrisilazane. Other silazanes, including those functionalized with vinyl, amino, or fluoro groups, may likewise be employed. Other alkyl-, aryl-, fluoro-, or heteroatom- substituted silanes, including mixtures and derivatives thereof, may also be utilized within the scope of the present disclosure.

[0100] The hydrolysable silanes suitable for use in the coating composition may be represented by the general formula RnSi(OR’)4-n, where R is a non- hydrolyzable organic radical, which may be functional or non-functional; OR’ is a hydrolysable group such as an alkoxy group in which R’ is typically a Ci toC4 alkyl (i.e., methyl, ethyl, propyl, or butyl); and n is an integer from 0 to 3. This structural flexibility allows tailoring of both the reactivity and functionality of the silane precursor to suit a range of performance requirements in the coating composition.

[0101] In certain embodiments, the solvent component of the coating composition may comprise one or more protic or aprotic solvents, which may be used individually or in combination. Suitable solvents are selected to dissolve the hydrolysable silane precursor and, where present, an organic polymeric resin, and to facilitate or mediate the hydrolysis and condensation reactions involved in the coating formulation and film formation.Representative classes of solvents include Ci to Cs alcohols, glycols and glycol ethers, ketones and diketones, esters and carbonates, aromatic or mixed solvents, bio solvents derived from renewable feedstocks, as well as water, super- or near-critical carbon dioxide (CO2), or super- or near-critical nitrous oxide (N2O). In certain embodiments, the amount of water employed for hydrolysis may be expressed as a hydrolysis ratio (R), defined as the molar ration of alkoxy groups to water, which may range from about 0.1: 10 to about 10:0.1.

[0102] Representative alcohol solvents include methanol, ethanol, n- propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, various pentanols, and benzyl alcohol. Suitable glycols and glycol ethers include ethylene glycol, propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), dipropylene glycol monomethyl ether (DPM), and diethylene glycol diethyl ether. Exemplary ketone and diketone solvents include acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, and diacetone alcohol. Esters and carbonates may include ethylacetate, butyl acetate, propylene carbonate, dimethyl carbonate, and y- valerolactone. Exemplary biosolvents may include ethyl lactate, methyl soyate, dimethyl isosorbide, and other bio-derived esters or carbonates. In certain embodiments, the solvent may also comprise aromatic or mixed solvents such as toluene or xylenes. The selection and proportion of solvent(s) may vary depending on the intended application, drying or curing conditions, and solubility compatibility with the hydrolysable silane precursor, the organic polymeric resin, or other formulation components.

[0103] In certain embodiments, the coating composition further comprises one or more additives selected from cross-linking agents, curing agents, or catalysts. These additives may be included to promote film formation, accelerate or initiate curing reactions, enhance network density, or catalyze hydrolysis and condensation of silane precursors. Suitable additives include organometallic alkoxides, latent acids or bases, external cross-linkers, photoinitiators, and hydrolysis catalysts. The specific selection and concentration of each additive may vary depending on the formulation requirements, substrate type, desired cure mechanism, and end-use performance properties of the final coating.

[0104] Organometallic alkoxides may be added to the coating composition to catalyze condensation and cross-linking reactions. Representative examples include titanium isopropoxide, tetra-n-butyl titanate, zirconium n-propoxide, aluminum sec-butoxide, zinc octoate, dibutyltin dilaurate, phosphorous- containing alkoxides such as triethyl phosphate or trialkyl phosphites, and metal alkoxides bearing larger or branched alkoxide groups to modify reactivity. In certain embodiments, metal acetylacetonates may also be used, including titanium acetylacetonate, zirconium acetylacetonate, aluminumacetylacetonate, and zinc acetylacetonate. Chelating agents may likewise be employed to control the hydrolysis and condensation rates of metal alkoxides, including acetic acid, isobutyric acid, methacrylic acid, acetylacetone, and 2,2'- bipyridine, as well as other 0-diketones, carboxylic acids, or multidentate ligands to stabilize the metal alkoxides. In certain embodiments, hydrolysispromoting acids may be employed to accelerate precursor reactivity, including camphorsulfonic acid, mandelic acid, glycolic acid, lactic acid, tartaric acid, phenylphosphonic acid, and phosphonic acid. Latent acids and bases may also be employed, such as blocked p-toluenesulfonic acid, dodecylbenzenesulfonic acid, imidazole-blocked sulfonic acids, and hexamethylenetetramine, which release active species upon heating or curing.

[0105] External cross-linkers may be added to the coating composition to further enhance film durability or chemical resistance. Representative examples include amino resins such as hexamethoxymethyl melamine (HMMM), benzoguanamine, and urea-formaldehyde; blocked polyisocyanates such as HDI trimer and s-caprolactam-blocked isocyanates; IPDI allophanate derivatives; as well as other multifunctional cross-linkers such as aziridines, polycarbodiimides, oxazolidines, and polysiloxane-based hydrosilylation agents.

[0106] In embodiments where UV-curing or photo-initiation is a desired curing method, suitable photoinitiators may be used as the additive, including a-hydroxy ketones, phosphine oxides, and benzophenone derivatives. Hydrolysis catalysts may also be added to control the rate of silane hydrolysis and condensation. These may include organic acids (i.e., acetic acid, formic acid), mineral acids (i.e., hydrochloric acid, nitric acid), and organic or inorganic bases.

[0107] In general, the hydrolysable silane is added to the coating composition in an amount of about 5 wt% to about 99.9 wt%, and the solvent is added in an amount of about 1 ppm to about 85 wt%. The weight percentages are based on the total uncured composition weight, and the combined weight percent of all components in the composition is 100 wt%.

[0108] When the one or more additives selected from cross linking agents, curing agents, or catalysts are added to the coating composition, these components are generally added to the coating composition in an amount of about 1 ppm to about 25 wt%. The weight percentages are based on the total uncured composition weight, and the combined weight percent of all components in the composition is 100 wt%.

[0109] For clarity, the term “total uncured composition weight” as used herein refers to the total weight of the composition prior to application onto a metallic substrate and before undergoing any curing or drying process. This is distinguishable from the “total cured composition weight,” which refers to the weight of the resulting film or residue remaining on the metallic substrate after solvent evaporation and completion of the curing process. Curing may involve thermal treatment, ultraviolet irradiation, ambient conditions, or a combination thereof, and typically results in the condensation of silane precursors into a cross-linked, inorganic-organic hybrid network, optionally including reaction products of resins, additives, or cross-linkers. The cured composition therefore comprises those components that remain as part of the final coating film and excludes volatile solvents or unreacted materials that are lost during processing.

[0110] In one non-limiting example, the coating composition comprises a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt%. The composition further comprises a solvent in an amount of about 0.1 wt% to about 85 wt. The weight percentages of these components are based on the total uncured composition weight and sum to 100 wt%.

[0111] In another one non-limiting example, the coating composition comprises a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt%. The composition further comprises a solvent in an amount of about 0.1 wt% to about 85 wt%, and one or more additives selected from cross-linking agents, curing agents, or catalysts in an amount of about 0.1 wt% to about 25 wt%. The weight percentages of these components are based on the total uncured composition weight and sum to 100 wt%.

[0112] In another non-limiting example, the hydrolysable silane comprises an epoxy-functional silane selected from y-glycidoxypropyltrimethoxysilane (GPTMS), y-glycidoxypropyltriethoxysilane, or mixtures thereof. These functional trialkoxy silanes are particularly useful in the coating composition due to their ability to participate in both inorganic and organic network formation. The glycidoxy group offers reactivity toward nucleophilic groupssuch as amines, acids, and hydroxyls, facilitating covalent bonding with organic polymeric resins or cross-linkers, while the alkoxysilane moiety undergoes hydrolysis and condensation to form siloxane linkages. This dual reactivity enables strong interfacial bonding between the coating and the metallic substrate, as well as improved cohesion within the coating matrix. GPTMS and its triethoxy analog are employed as coupling agents, adhesion promoters, or network precursors in hybrid sol-gel systems. Their use provides a balance of hydrolytic reactivity, film-forming capability, and chemical resistance that is advantageous for applications requiring durable, high- performance coatings on metal surfaces. In certain embodiments, the epoxyfunctional silane may be used as the sole silane precursor or in combination with other hydrolysable silanes to tailor mechanical flexibility, cure kinetics, or substrate adhesion.

[0113] In another non-limiting example, the coating composition further comprises a plurality of inorganic nanoparticles having an average particle size of about 1 nanometer (nm) to about 100 nanometers (nm). The inorganic nanoparticles may be selected from SiCh, (including colloidal silica, fumed silica, or fused silica), Z1O2, TiCh, MgO, CeCh, boron oxide, iron oxide, alumina, aluminum-doped zinc oxide (AZO), indium tin oxide (ITO), zinc ocide, graphene oxide, nano clay, quartz, boron nitride nanoparticles or sheets, and boehmite alumina, and may be present in the composition in an amount of about 0 wt% to about 20 wt%, based on the total uncured composition weight. It should be understood that the plurality of inorganic nanoparticles may be present in trace amounts. For example, coating composition may comprise inorganic nanoparticles in an amount of about 1 ppm. The inclusion of the plurality of inorganic nanoparticles can significantly enhance the mechanical, thermal, and barrier properties of the cured coating. Specifically, the pluralityof inorganic nanoparticles improves scratch resistance, abrasion resistance, and hardness while maintaining film flexibility and optical clarity when properly dispersed. Silica nanoparticles (SiCti) increase the hardness and the thermal stability of the cured coating, while also improving surface smoothness. Zirconia (ZrCti) and titania (TiCti) nanoparticles offer thermal and chemical resistance and may contribute to photocatalytic or UV-blocking functionality. Boehmite alumina, a high-surface-area aluminum oxide phase, improves film reinforcement and reduces water permeability. In some embodiments, the nanoparticles may be surface modified (i.e., with silanes or other coupling agents) to improve their compatibility and dispersion within the silane matrix or with any organic polymeric resins present. Proper dispersion of the nanoparticles within the coating matrix is critical to achieving uniform film properties and avoiding agglomeration or sedimentation during storage or application. The nanoparticles may be incorporated by high shear mixing, ultrasound mixing, sonication, or other suitable dispersion techniques. The use of inorganic nanoparticles in a particle size of about 1 rnn to about 100 nm allows the coating to maintain desirable transparency and processability while delivering improved durability and performance in demanding environments.

[0114] According to another embodiment, the coating composition further comprises, a functional additive such as a corrosion inhibitor, a flow or leveling agent, a plurality of nanoparticles, a friction reducer, a UV stabilizer, a pigment, an adhesion promoter, a friction reducer, or a defoamer. These additives may be included to impart or enhance specific performance characteristics of the coating, such as corrosion resistance, flow behavior, mechanical durability, ultraviolet stability, color or appearance, substrate adhesion, or processability.

[0115] Representative examples of suitable corrosion inhibitors include cerium(III) nitrate, lanthanum acetate, zinc phosphate, strontium aluminum polyphosphate, benzotriazole, and 8 -hydroxy quinoline, as well as boron- containing compounds such as triethyl borate and other borates, and phosphorus-containing compounds such as triethyl phosphate. Other inorganic, organic, or organometallic corrosion inhibitors may likewise be employed. The corrosion inhibitors function by passivating the metal surface, forming protective complexes, or scavenging reactive species that contribute to corrosion. Flow or leveling agents may include polyether-modified polysiloxanes, fluoropolyether surfactants, and acrylate-siloxane comb polymers, which improve surface smoothness, reduce defects such as craters or orange peel, and promote even film formation during drying or curing. In some embodiments, the functional additive may comprise a plurality of nanoparticles, such as fumed or colloidal silica (SiCti), alumina, boehmite alumina, titanium dioxide (TiCti), zirconium dioxide (ZrCti), cerium dioxide (CeCh), magnesium oxide (MgO), boron oxide, iron oxides, graphene oxide, carbon nanotubes (CNTs), hexagonal boron nitride (h-BN), nanodiamonds, or polyhedral oligomeric silsesquioxane (POSS) cage structures (i.e., SiOi.s). The plurality of nanoparticles can enhance the mechanical strength, thermal resistance, barrier performance, or electrical conductivity of the coating. Friction-reducing additives may be included to reduce surface wear, lower the coefficient of friction, or prevent galling in applications with moving or contacting parts. Examples include polytetrafluoroethylene (PTFE) micropowder, tungsten disulfide (WS2) nanotubes, molybdenum disulfide (M0S2), and ultra-high molecular weight polyethylene (UHMWPE) waxes. To improve UV resistance, the coating composition may include one or more UV stabilizers such as benzotriazoles (i.e., Tinuvin® 328), hydroxyphenyl-triazines (i.e., Tinuvin® 400), oxalanilides, and hindered amine light stabilizers (HALS)such as Chimassorb® 944 or Tinuvin® 770. Pigments may be included in the coating composition for aesthetic or functional coloration and may include carbon black, titanium dioxide (in red, yellow, black, or white forms), aluminum flake, mica-TiCE pearl pigments, SiCE-coated aluminum flakes, and holographic polyethylene terephthalate (PET) flakes. Adhesion promoters may be added to improve bonding of the coating to the substrate, including compounds such as vinylpho sphonic acid, phosphate ester silanes, and zirconate-based coupling agents (i.e., neoalkoxyzirconates). Finally, to reduce or eliminate surface defects such as foaming or bubbling during application or cure, defoamers such as synthetic hectorite clay, urea-urethane compounds, or polysiloxane-based defoamers may be used. The inclusion of functional additives may be tailored based on the performance requirements of the intended application, and in some embodiments, multiple additives may be used synergistically to achieve desired coating properties without adversely affecting stability, shelf life, or processability.

[0116] In general, when the functional additive is added to the coating composition, it is added in an amount of about 0 wt% to about 35 wt% of the total uncured composition weight. It should be understood that the functional additive may be present in trace amounts, such as 1 ppm. For example, in another non-limiting example, the coating composition comprises a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, and present in an amount of about 15 wt% to about 99.9 wt%. The composition further comprises a solvent in an amount of about 1 ppm to about 85 wt%; one or more additives selected from cross-linking agents, curing agents, and catalysts, present in an amount ofabout 1 ppm to about 25 wt%; and a functional additive present in an amount of about 1 ppm to about 35 wt%. Wherein the weight percentages for each component are based on the total uncured composition weight, and the combined total of all components in the composition is 100 wt%.

[0117] According to another embodiment, the coating composition further comprises an organic polymeric resin. Suitable organic polymeric resins include any film-forming organic polymer that remains stable under sol-gel conditions and is compatible with the hydrolysis and condensation of the silane precursors. In certain embodiments, the organic polymeric resin may be waterbased and / or solvent-based and may contain functional groups such as hydroxyl, epoxy, carboxyl, amino, or isocyanate moieties. These functional groups may participate in covalent bonding with the siloxane network or with other cross-linkers and additives, thereby enhancing mechanical integrity and interphase adhesion in the hybrid coating. Representative classes of organic polymeric resins include (meth)acrylic polymers, polyesters, polyurethanes, epoxides, epoxy esters, chlorinated rubber, water-based emulsion polymers, silicone and polysiloxane hybrids such as polydimethylsiloxane (PDMS), polyimides, polyamide-imides, polybenzoxazines, polyamides, polyetherimides, cyanate esters, fluoropolymers, phenolics, melamineformaldehyde resins, urea-formaldehyde resins, alkyds, vinyl resins, polycarbodiimides, polyphosphazenes, polytriazines, maleated polyketones, polybenzimidazoles, silane-grafted acrylic latexes, sulfonated polyesters, and silane-terminated polyurethanes. Exemplary acrylate UV-curable resins and monomers may be selected from polyurethane acrylates, epoxy acrylates, and polyester acrylates, including monomers such as hexanediol diacrylate (HDD A), trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate, and isobornyl acrylate. In certain embodiments, the resin may be selected tocomplement the desired mechanical or optical properties of the coating, or to provide compatibility with a particular substrate or curing process. Other functionalized, hybrid, or specialty organic resins may likewise be employed within the scope of the present disclosure.

[0118] Representative examples of (meth)acrylic resins include polymethyl methacrylate (PMMA), methyl methacrylate -styrene copolymers, butyl methacrylate-styrene copolymers, fluorinated PMMA, and hydroxyethyl acrylate copolymers. Exemplary polyester resins include those based on saturated or unsaturated ortho-phthalic, iso-phthalic, or tere-phthalic acid backbones, as well as polycaprolactone diol-derived polyesters. Suitable polyurethane resins may include polyester-urethane, polyether-urethane, and polycarbonate-urethane types, as well as prepolymers derived from blocked hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), or methylene diphenyl diisocyanate (MDI). Exemplary epoxide resins include bisphenol-A diglycidyl ether, bisphenol-F-based epoxies, novolac resins, aliphatic glycidyl ethers, and cycloaliphatic epoxy compounds. Suitable silicone and polysiloxane hybrid resins may include MQ-resins, T-resins, and polysiloxane-urethane hybrids, and other silicone-based polymers. Fluoropolymer resins may include polyvinylidene fluoride (PVDF) and fluoroethylene-vinyl ether (FEVE) resins, which are valued for their excellent weatherability and chemical resistance. Vinyl resins may include poly( vinyl butyral), poly( vinyl alcohol) (PVA), and poly( vinyl acetate), polyvinylpyrrolidone (PVP, and poly( vinyl chloride) (PVC), each offering desirable properties such as flexibility, adhesion, or solubility compatibility. Additional thermosetting resins may include phenolics, melamineformaldehyde, urea-formaldehyde, and benzoguanamine-formaldehyde resins. The selection and loading of the organic polymeric resin can be tailored basedon desired coating properties, including flexibility, hardness, weathering resistance, solvent resistance, or adhesion to specific substrates.

[0119] In general, when the organic polymeric resin is added to the coating composition, it is added in an amount of about 0 wt% to about 60 wt% of the total uncured composition weight. It should be understood that the organic polymeric resin may be present in trace amounts, such as 1 ppm. For example, in another non-limiting example, the coating composition comprises a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, and present in an amount of about 15 wt% to about 99.9 wt%. The composition further comprises a solvent in an amount of about 0.1 wt% to about 85 wt%; one or more additives selected from cross-linking agents, curing agents, and catalysts, present in an amount of about 0.1 wt% to about 25 wt%; a functional additive in an amount of about 0.1 wt% to about 35 wt%; and an organic polymeric resin present in an amount of about 1 ppm to about 60 wt%. Wherein the weight percentages for each component are based on the total uncured composition weight, and the combined total of all components in the composition is 100 wt%. It has been found that the coating composition exhibits superior performance properties when the ratio of the functional additives to the organic polymeric resin is between 0.1 to 1 and 10 to 1.

[0120] In another non-limiting example, the organic polymeric resin comprises a polyester-urethane resin having a molecular weight of about 800 grams per mole to about 3,000 grams per mole. The polyester-urethane resin may act synergistically with the hydrolysable silane precursor to form aninterpenetrating or chemically bonded organic -inorganic hybrid network. A molecular weight of the polyester-urethane resin in the range of approximately 800 to 3,000 grams per mole, provides a balance between flexibility and crosslinking density, allowing for durable, adherent coatings with resistance to cracking, chipping, or delamination under thermal or mechanical stress. Additionally, the polyester-urethane resin offers tunable properties such as gloss, hardness, and abrasion resistance, making them especially advantageous for use in wheel coating applications and other high-performance environments.

[0121] In another non-limiting example a molar ratio of silicon atoms in the hydrolysable silane to carbon atoms in the organic polymeric resin is from about 0.5: 1 to about 5: 1. A lower hydrolysable silane to carbon molar ratio (i.e., -0.5: 1 ) favors higher organic content, which may improve the flexibility and impact resistance of the cured film. Conversely, a higher hydrolysable silane to carbon molar ratio (i.e., -5: 1) increases the relative content of the inorganic network, promoting properties such as hardness, thermal stability, corrosion resistance, and environmental durability. The ratio may be calculated based on the molecular structure and loading levels of each component in the uncured composition and may vary depending on the functional groups available for network formation or the molecular weight of the resin.

[0122] Further provided is a method of forming a corrosion-resistant coating on a metallic substrate, the method comprising: (a) preparing a coating composition; (b) applying the coating composition to at least a portion of the metallic substrate to form a wet film; and (c) curing the wet film to obtain a dry film.

[0123] The metallic substrate may comprise any metal surface suitable for receiving a corrosion-resistant coating, including but not limited to structural metals, fabricated components, or precision-machined parts. In certain embodiments, the metallic substrate may comprise: ferrous metals such as iron, carbon steel, and stainless steel; non-ferrous metals such as aluminum, copper, zinc, magnesium, and titanium; and metal alloys such as galvanized steel, brass, bronze, Inconel, and nickel-chromium alloys. The coating composition may be applied to specific metal articles such as automotive components (i.e., wheels, brake rotors, calipers, chassis components, heat exchangers, radiators, and exterior body panels); aerospace components (i.e., fuselage panels, wing structures, engine housings, and landing gear); industrial equipment (i.e., pipes, valves, flanges, tanks, and structural frames); consumer goods (i.e., appliances, cookware, tools, and electronic enclosures); construction materials (i.e., roofing panels, window and door frames, railings, and fasteners); and energy or infrastructure-related components (i.e., wind turbine fixtures, solar panel frames, electrical transmission towers, pipelines, and storage tanks). The metallic substrate is not limited to these examples and may be used on any other metallic surface for which enhanced corrosion resistance, durability, or functional coating performance is desired.

[0124] In certain embodiments, the coating composition may comprise any combination of: a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having from 1 to 4 hydrolysable groups, and present in an amount of about 15 wt% to about 99.9 wt%; a solvent in an amount of about 0.1 wt% to about 85 wt%; one or more additives selected from crosslinking agents, curing agents, and catalysts, present in an amount of about 0.1wt% to about 25 wt%; a functional additive in an amount of about 0.1 wt% to about 35 wt%; and an organic polymeric resin present in an amount of about 0.1 wt% to about 60 wt%. Wherein the weight percentages for each component are based on the total uncured composition weight, and the combined total of all components in the composition is 100 wt%. The components may be combined in any workable order, at a temperature ranging from about 5 °C to about 90°C, and mixed until a visually homogeneous composition is obtained.

[0125] In certain embodiments, the coating composition may be applied to at least a portion of the metallic substrate, up to and including, the entire surface of the substrate, to form a wet film. The coating may be applied by any suitable method, including but not limited to spraying, brushing, rolling, dipping, flow coating, or spin or coil coating, depending on the geometry of the substrate, the desired film thickness, and the processing conditions. The coating may be applied selectively to areas most susceptible to corrosion, such as exposed edges, welds, or connection points, or may be applied uniformly over the entire substrate to ensure comprehensive protection.

[0126] For clarity, the term “wet film” as used herein refers to the applied layer of coating composition in its uncured or partially cured state, following deposition onto the metallic substrate. The wet film comprises the formulation of the coating composition, including volatile components such as solvents and unreacted monomers or oligomers, as well as non-volatile solids such as silane precursors, resins, catalysts, cross-linkers, and functional additives. The thickness, uniformity, and flow behavior of the wet film may be influenced by factors such as viscosity, application method, ambient temperature, and substrate surface energy. The wet film is typically a fluid and may require a defined dwell time, flash-off period, or staged drying phase before undergoingfull curing. This is distinguishable from the “dry film,” which refers to the solid coating layer remaining after the curing process has been completed. The dry film does not contain volatile solvents and comprises a chemically cross-linked network formed from the hydrolyzed and condensed silanes and any reacted organic polymeric resins or cross-linkers. The dry film exhibits the final physical, chemical, and performance properties of the coating, including adhesion to the substrate, corrosion resistance, hardness, flexibility, solvent resistance, and environmental durability. The transformation from wet film to dry film may involve thermal, UV, or ambient curing.

[0127] In certain embodiments, the wet film may be cured by thermal means, ultraviolet means, ambient atmospheric conditions, microwave irradiation, plasma-assisted densification, or a combination of the foregoing, to obtain a dry film. Thermal curing may involve heating the coated substrate to a temperature sufficient to promote the condensation of hydrolyzed silane groups and the cross-linking of organic and inorganic components, typically within a range of about 50°C to about 250°C, for a duration ranging from minutes to hours, or more, depending on the specific formulation and desired film properties. Infrared (IR) ovens may also be employed to deliver focused, efficient thermal energy, allowing for more uniform and rapid curing while reducing energy consumption or thermal stress on the substrate. Microwave curing may involve exposing the coated substrate to microwave irradiation, providing volumetric heating that accelerates condensation reactions and reduces cure times without excessive surface heating. Plasma-assisted densification may involve exposing the wet or partially cured film to low- pressure or atmospheric plasma to enhance network formation, reduce porosity, and increase hardness and barrier properties. UV curing may involve exposure to ultraviolet radiation at sufficient intensity and duration to activatephotoinitiators present in the coating composition and initiate polymerization or cross-linking reactions. In some embodiments, the total applied UV energy may range from about 100 mJ / cm2to about 3000 mJ / cm2. In some embodiments, UV curing is used in combination with thermal curing, either sequentially or simultaneously, to accelerate cure rates, reduce energy requirements, or enhance final film properties such as hardness, adhesion, and solvent resistance. In yet other embodiments, ambient curing may be employed, wherein the coated substrate is exposed to atmospheric conditions, such as room temperature and ambient humidity, without the need for elevated heat or UV exposure. This may be advantageous for large structures, temperature-sensitive substrates, or field applications where thermal or UV curing equipment is not readily accessible. The selected curing method may be tailored based on the chemistry of the formulation, the type of substrate, the application environment, and processing constraints. For example, thermal curing may be preferred for high-temperature-resistant substrates or industrial applications, while UV curing may be used for rapid throughput in high-speed manufacturing settings or for temperature-sensitive substrates. In certain embodiments, dual-cure systems may be employed, wherein partial UV curing establishes initial film integrity, followed by thermal curing to complete the network formation.

[0128] In certain embodiments, the wet film is cured at a temperature of about 50°C to about 250°C. This temperature range is generally sufficient to promote the hydrolysis and condensation of silane precursors, initiate or accelerate cross-linking reactions involving organic polymeric resins and additives, and evaporate residual solvent or other volatile components. Curing within this range can result in the formation of a robust, adherent, and corrosion-resistant dry film exhibiting desirable mechanical, chemical, andenvironmental performance properties. The exact curing temperature selected may vary based on factors such as the specific silane chemistry, the presence of organic resins or thermally activated cross-linkers, the substrate type, desired cure rate, and equipment capabilities. It is to be understood, however, that any suitable temperature may be used, including those outside the 50°C to 250°C range, so long as the conditions are sufficient to achieve the desired degree of curing without adversely affecting the coating composition or substrate. For example, lower temperatures may be employed in formulations containing highly reactive components or catalysts, while higher temperatures may be used in industrial environments with heat-tolerant substrates to accelerate throughput or maximize cross-linking density. In some embodiments, stepwise or staged thermal profiles may be used to balance solvent evaporation, film formation, and final cure. The selected temperature should be sufficient to yield a continuous, uniform, and durable coating layer appropriate for the intended application.

[0129] In certain embodiments, the dry film has a thickness of about 0.1 pm to about 100 pm. This thickness range has been found suitable to provide effective corrosion resistance, substrate protection, and mechanical integrity without adversely impacting surface appearance, weight, or dimensional tolerances. Thin coatings near the lower end of the range (i.e., —0.1 5 pm) may be advantageous for applications requiring minimal film buildup, transparency, or high-precision tolerances, while thicker coatings (i.e., -25-100 pm) may be desirable for harsh environments, extended service life, or where enhanced barrier properties, impact resistance, or wear resistance are required. It is to be understood, however, that any suitable dry film thickness may be used, including values outside the 0.1 pm to 100 pm range, so long as the resulting coating provides adequate performance for the intended application. Theselected film thickness may depend on factors such as the specific formulation of the coating composition, the method of application of the wet film (i.e., dip, spray, brush, roll), the nature of the metallic substrate, the required corrosion protection performance, and downstream processing or functional requirements.

[0130] In certain embodiments, multiple coating layers may be sequentially applied to the metallic substrate. In such embodiments, a first coating composition is applied to at least a portion of the metallic substrate to form a first wet film, which is then cured by thermal means, ultraviolet means, or a combination thereof to yield a first dry film. Once the first dry film has been produced, the first layer is complete. A second coating composition, which may be chemically identical to or different from the first coating composition, may be subsequently applied and cured using the same or different curing method to form a second dry film, and thereby a second layer. This process may be repeated as many times as necessary to achieve the desired film architecture, functional performance, or thickness. For example, the first dry film may serve as an adhesion-promoting primer or conversion layer, a second dry film may provide barrier or corrosion-inhibiting properties, and a third dry film may provide aesthetic or mechanical features such as color, gloss, or scratch resistance. In some embodiments, each layer is applied and cured independently before the next is deposited, ensuring discrete stratification and optimal curing conditions. In other embodiments, partial curing may be used between layers to promote interlayer bonding or gradient functionality.

[0131] In certain embodiments, the dry film may be further treated with a post-coating treatment to enhance its performance, durability, or aesthetic characteristics. The post-coating treatments may include, but are not limited to,the application of a clear coat, a plasma treatment, a chemical sealing, or a mechanical polishing. A clear coat may be applied over the dry film to provide additional protection against abrasion, UV degradation, and environmental wear, while also enhancing gloss and depth of color. Suitable clear coats may include acrylic, polyurethane, or siloxane-based formulations, and may be applied via spray, dip, or flow-coating techniques followed by an appropriate curing process. A plasma treatment, such as atmospheric or low-pressure plasma, may be used to modify the surface energy of the dry film, enhance hydrophobic or hydrophilic behavior, and promote adhesion of subsequent layers. The plasma treatment can also remove residual contaminants and further cross-link the surface layer, thereby improving chemical resistance and surface hardness. A chemical sealing involves the application of a reactive solution, such as a chromate-free sealant, phosphate, or silicate-based solution, that penetrates and seals the porosity of the dry film, forming a secondary protective layer. This can improve the corrosion resistance of the coated substrate, particularly in harsh service environments. A mechanical polishing may be employed to smooth the dry film, improve surface uniformity, reduce roughness, or impart a desired finish or luster. The mechanical polishing may also remove superficial defects or particulate contaminants and is especially useful when an aesthetically pleasing surface appearance is required. In some embodiments, combinations of the post-coating treatments may be used to synergistically enhance the coating performance. The selection of the specific post-treatment technique(s) may depend on the intended end-use, environmental exposure, and substrate geometry.

[0132] In one non-limiting example, the curing step comprises curing the wet film at a temperature of about 50°C to about 250°C for a duration of about 5 minutes to about 120 minutes. The curing conditions may be selected tooptimize the condensation of hydrolyzed silane groups, promote cross-linking of organic and inorganic components, and remove residual solvent or volatile byproducts. These conditions are generally sufficient to develop a mechanically stable, adherent, and corrosion-resistant dry film.

[0133] In another non-limiting example, the metallic substrate comprises an aluminum wheel. When applied to at least a portion of the wheel surface, the corrosion-resistant coating provides a uniform, adherent, and durable protective barrier that resists corrosion mechanisms.

[0134] In another non-limiting example a sol-gel coating composition was prepared by mixing, by weight, 12 parts 3-glycidoxypropyltrimethoxysilane (GPTMS), 8 parts tetraethoxysilane (TEOS), 65 parts ethanol, 10 parts deionized water, 1 part acetic acid (0.1 M), and 4 parts epoxy resin. The silanes (GPTMS and TEOS), ethanol, deionized water, and acetic acid were combined and stirred for approximately 2 hours at room temperature to initiate hydrolysis and partial condensation. Following this, the epoxy resin dispersion was added to the mixture and stirred for an additional 30 minutes to ensure uniform incorporation. The resulting sol-gel composition was then applied to a cleaned and deoxidized 6061 aluminum alloy panel via spray coating. The coated panel was subsequently cured in an oven at 180°C for 30 minutes. The resulting cured sol-gel film was clear, hard, and demonstrated enhanced corrosion resistance on visual inspection and preliminary performance testing. In addition to corrosion protection, the cured sol-gel film exhibited advantageous properties such as ease of cleaning, hydrophobic behavior, and improved color encapsulation, thereby enhancing both functional durability and aesthetic performance. In certain embodiments, the sol-gel may have a pH in the rangeof about 1 to 6, which facilitates controlled hydrolysis and condensation of the silane precursors.

[0135] The corrosion resistance of the cured sol-gel film was evaluated in accordance with internationally recognized test standards. In particular, the coating was subjected to filiform corrosion testing according to DIN EN ISO 4623-2 (equivalent to ASTM D2803). The acceptance criterion for this test specifies that the length of filiform corrosion propagation from an intentionally introduced scribe should be less than 2 mm. Following the defined exposure period, the maximum filiform corrosion length observed was less than 1 mm from the scribe line, thereby surpassing the minimum requirement and demonstrating effective inhibition of underfilm corrosion.

[0136] Neutral salt spray (NSS) testing was performed in accordance with DIN EN ISO 9227 NSS (equivalent to ASTM Bl 17). The acceptance criteria specify that the coated surface should remain free of corrosion products, blistering, or delamination after continuous exposure to a fog of neutral sodium chloride solution. Upon completion of the prescribed test interval, the coated panels exhibited no observable corrosion, blistering, or delamination, thereby fully satisfying the standard and confirming the barrier integrity of the sol-gel film.

[0137] Copper-accelerated acetic acid salt spray (CASS) testing was conducted in accordance with DIN EN ISO 9227 CASS (equivalent to ASTM B368). This accelerated corrosion test subjects coated specimens to a continuous fog of acetic acid salt solution containing copper chloride at an elevated temperature. The acceptance criteria require that no red rust, blistering, or coating degradation be observed and that corrosion creep from thescribe not exceed 2 mm. Following the defined exposure duration, the coated specimens exhibited no red rust, blistering, or coating degradation, and the measured corrosion length from the scribe was less than 1 mm. These results substantially exceeded the acceptance threshold, confirming the durability of the coating under highly aggressive conditions.

[0138] Taken together, these test results confirm that the transparent sol-gel coating provides excellent corrosion protection for aluminum alloy substrates. The performance consistently exceeded the acceptance criteria defined by the applicable international standards, with measured corrosion propagation limited to less than 1 mm and no observable surface degradation. These results demonstrate that the sol-gel coating composition provides a level of corrosion protection that is at least comparable to, and in many cases superior to, widely used chromate- or epoxy -based surface treatments, while offering the added benefits of transparency and compatibility with subsequent topcoats.

[0139] Further provided is a coating composition comprising a cross-linked, inorganic-organic hybrid network formed from curing an uncured composition comprising (i) a hydrolysable silane precursor; and (ii) a solvent. The uncured composition may further comprise (iii) one more additives selected from crosslinking agents, curing agents, or catalysts; (iv) a functional additive; or (v) an organic polymeric resin.

[0140] In one embodiment, the coating composition comprising a crosslinked inorganic-organic hybrid network formed from curing an uncured composition comprising (i) a hydrolysable silane precursor; and (ii) a solvent, further comprises (iii) one more additives selected from cross-linking agents, curing agents, or catalysts; (iv) a functional additive such as a corrosioninhibitor, a flow or leveling agent, a plurality of nanoparticles, a friction reducer, a UV stabilizer, a pigment, an adhesion promoter, a friction reducer, or a defoamer. Any yet, in other embodiments (v) an organic polymeric resin.

[0141] In one non-limiting example the hydrolysable silane precursor is selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having 1 to 4 hydrolysable groups and is present in an amount of about 15 wt% to about 99.9 wt% of the uncured composition. The solvent is present in an amount of about 0.1 wt% to about 85 wt% of the uncured composition. The one or more additives are selected from cross-linking agents, curing agents, and catalysts, and present in an amount of about 0.1 wt% to about 25 wt% of the uncured composition.

[0142] The following information is incorporated herein by reference in entirety: U.S. Patent No. 6,440,290 (Attachment A), U.S. Patent No. 9,364,821 (Attachment B), and publication entitled “Sol-gel proceess: an overview”, Ana C. Marques, 22 June 2007, Lehigh University (Attachment C).

[0143] The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope

Claims

What is claimed is:

1. A method of surface treating a vehicle wheel comprising the steps of:(a) providing a vehicle wheel having a surface;(b) pretreating the surface of the wheel to clean the surface from contaminants;(c) applying a coating onto the surface of the wheel, wherein the coating was formed by a sol-gel process; and(d) curing the coating to form a hardened coated layer on the surface of the wheel.

2. The method of claim 1, wherein the vehicle wheel is a vehicle wheel made of one of aluminum, aluminum alloys or steel, preferably a forged aluminum wheel, a cast aluminum wheel or a steel vehicle wheel.

3. The method of claim 1, wherein step (b) includes degreasing the surface to remove grease and other contamination from the surface.

4. The method of claim 1, wherein step (b) includes conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface.

5. The method of claim 1, wherein step (b) includes rinsing the surface with a deionized fluid.

6. The method of claim 1, wherein step (b) includes conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface.

7. The method of claim 1, wherein subsequently to step (b), drying the surface by applying heat.

8. The method of claim 1, wherein in step (c), first and second coatings are applied to the surface.

9. The method of claim 8, wherein the first and second coatings are made of the same components.

10. The method of claim 8, wherein the first and second coatings are nearly identical in composition.

11. The method of claim 8, wherein the first coating is substantially thinner in thickness than the second coating.

12. The method of claim 11, wherein the first coating has a thickness in the range of between 0.1 to about 5 micrometers.

13. The method of claim 11, wherein the second coating has a thickness in the range of between 5 to about 25 micrometers.

14. The method of claim 8, wherein after the application of the first coating, waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate.

15. A method of surface treating a vehicle wheel comprising the steps of:(a) providing a vehicle wheel having a surface;(b) pre-treating the surface of the wheel to clean the surface from contaminants;(c) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersed therein and was formed by a sol-gel process;(d) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate;(e) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and(f) curing the first and second coatings to form a hardened coated layer on the surface of the wheel.

16. The method of claim 15, wherein step (b) includes the steps of:(1) degreasing the surface to remove grease and other contamination from the surface;(2) conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface; and(3) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface.

17. The method of claim 16, wherein the first coating has a thickness in the range of between 0.1 to about 5 micrometers.

18. The method of claim 16, wherein the second coating has a thickness in the range of between 5 to about 25 micrometers.

19. A method of surface treating a commercial vehicle wheel comprising the steps of:(a) providing a vehicle wheel having a surface;(b) polishing the surface with abrasive polish to obtain a relatively smooth finish on the surface;(c) pre-treating the surface of the wheel to clean the surface from contaminants and prepare the surface a coating process, wherein the pretreating process includes the steps of:(1) degreasing the surface to remove grease and other contamination from the surface;(2) conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface;(3) rinsing the surface with a deionized fluid; and(4) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface;(d) drying the surface by applying heat;(e) subsequently to step (d), cooling the surface;(f) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersed therein and, wherein the first coating was formed by a sol-gel process;(g) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate;(h) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and(i) curing the first and second coatings by subjecting the first and second coatings to heat to form a hardened coated layer on the surface of the wheel; and(j) subsequently to step (i), cooling the hardened coated layer.

20. A vehicle wheel having a surface treated by the methods of claims 1, 15, or 19.

21. The vehicle wheel of claim 19, wherein the vehicle wheel is a vehicle wheel made of one of aluminum, aluminum alloys or steel, preferably a forged aluminum wheel, a cast aluminum wheel or a steel vehicle wheel.

22. A method of surface treating a commercial forged aluminum vehicle wheel comprising the steps of:(a) providing a vehicle wheel having a surface;(b) polishing the surface with abrasive polish to obtain a relatively smooth finish on the surface;(c) pre-treating the surface of the wheel to clean the surface from contaminants and prepare the surface a coating process, wherein the pretreating process includes the steps of:(1) degreasing the surface to remove grease and other contamination from the surface;(2) conducting an acid pickling process on the surface to remove impurities and corrosion products from the surface;(3) rinsing the surface with a deionized fluid; and(4) conducting a passivation process on the surface by triggering a chemical reaction with material at the surface to create an outer layer of shield material at the surface;(d) drying the surface by applying heat;(e) subsequently to step (d), cooling the surface;(f) applying a first coating onto the surface of the wheel, wherein the first coating includes solvents dispersed therein and, wherein the first coating was formed by a sol-gel process;(g) waiting for a duration of time to provide a flash off process to allow solvents within the first coating to evaporate;(h) applying a second coating onto the first coating, wherein the second coating was formed by a sol-gel process; and(i) curing the first and second coatings by subjecting the first and second coatings to heat to form a hardened coated layer on the surface of the wheel; and(j) subsequently to step (i), cooling the hardened coated layer.

23. The method of claim 1, wherein the coating provides at least one of the following benefits: ease of cleaning the coating, corrosion resistance, UV resistance, and scratch resistance.

24. A coating composition comprising:(a) a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to 99.9 wt%; and(b) a solvent present in an amount of about 0.1 wt% to about 85 wt%, wherein the combined weight percent of the composition is 100 wt%.

25. The composition of claim 24, wherein the hydrolysable silane comprises an epoxy-functional silane selected from y- glycidoxypropyltrimethoxysilane, y-glycidoxypropyltriethoxysilane, and mixtures thereof26. The composition of claim 24, further comprising a plurality of inorganic nanoparticles having an average particle size of about 2 nm to about 50 nm selected from SiCh, ZrCh, TiCh, MgO, CeCh, boron oxide, iron oxide, alumina, and boehmite alumina, and present in an amount of about 0.5 wt% to about 20 wt%.

27. The composition of claim 24, further comprising a functional additive present in an amount of about 0.1 wt% to about 35 wt%.

28. The composition of claim 24, further comprising an organic polymeric resin present in an amount of about 0.1 wt% to about 60 wt%.

29. The composition of claim 24, further comprising one or more additives selected from cross-linking agents, curing agents, and catalysts, present in an amount of about 0.1 wt% to about 25 wt%.

30. The composition of claim 29, further comprising an organic polymeric resin present in an amount of about 0.1 wt% to about 60 wt%.

31. The composition of claim 30, further comprising a functional additive present in an amount of about 0.1 wt% to about 35 wt%.

32. The composition of claim 31, wherein the organic polymeric resin comprises a polyester-urethane resin having a molecular weight of about 800 grams per mole to about 3,000 grams per mole.

33. The composition of claim 31, wherein a molar ratio of silicon atoms in the hydrolysable silane to carbon atoms in the organic polymeric resin is from about 0.5: 1 to 5: 1.

34. A method of forming a corrosion-resistant coating on a metallic substrate, the method comprising:(a) preparing a composition comprising:(1) a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to 99.9 wt%; and(2) a solvent present in an amount of about 0.1 wt% to about 85 wt%; wherein the combined weight percent of the composition is 100 wt%;(b) applying the composition to at least a portion of the metallic substrate to form a wet film; and(c) curing the wet film at a temperature of about 50°C to about 250°C and / or by ultraviolet irradiation to obtain a dry film having a thickness of about 0.1 pm to about 100 pm.

35. The method of claim 34, wherein the curing step comprises curing the wet film at a temperature of about 50°C to about 250°C for a duration of about 5 minutes to about 120 minutes.

36. The method of claim 34, wherein the metallic substrate comprises an aluminum wheel.

37. A coating composition comprising a cross-linked, inorganic- organic hybrid network formed from curing an uncured composition comprising (i) a hydrolysable silane selected from the group consisting of alkyl-, aryl-, amino-, epoxy-, vinyl-, methacryloxy-, mercapto-, isocyanato-, ureido-, fluoroalkyl-, sulfur-, thiocyanate-, acyl-, acetoxy-, phenyl-, chloro-, and bridging silanes, each having 1 to 4 hydrolysable groups, present in an amount of about 15 wt% to about 99.9 wt% of the uncured composition; and (ii) a solvent present in an amount of about 0.1 wt% to about 85 wt% of the uncured composition.

Images