High magnesium content aluminum alloy products including oxide coating for controlled atmosphere brazing

Abstract

Disclosed herein are an oxide coating layer which may be used to prevent MgO migration to a surface of a core aluminum alloy of an aluminum alloy product for use in heat exchangers. The core aluminum alloy may include a Mg content greater than 0.05 wt. %. By depositing the oxide coating layer on a surface of the core aluminum alloy, the aluminum alloy product tolerates higher amounts of Mg content while maintaining corrosion resistance and suitability for controlled atmosphere brazing (CAB) processes. The oxide coating layer prevents the MgO migration from within the core aluminum alloy to the surface of the core aluminum alloy, thereby preventing the MgO from disrupting the CAB processes. The present disclosure also provides unclad aluminum alloy products and clad aluminum alloy products including the core aluminum alloy as a core layer and / or one or more cladding layers.

Description

HIGH MAGNESIUM CONTENT ALUMINUM ALLOY PRODUCTS INCLUDING OXIDE COATING FOR CONTROLLED ATMOSPHERE BRAZINGCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 611,933, filed on December 19, 2023, the contents of which is hereby incorporated by reference in its entirety.FIELD

[0002] This disclosure relates to the fields of material science, material chemistry, metallurgy, aluminum alloys, aluminum alloy products, aluminum fabrication, and related fields. More specifically, the disclosure provides high magnesium content aluminum alloy products including a novel engineered oxide coating that can be used in a variety of applications, including, for example, as a protective layer for an aluminum alloy product (e.g., clad aluminum alloy product) for controlled atmosphere brazing.BACKGROUND

[0003] There has long been an interest in using recycled aluminum alloy materials for producing aluminum alloys. Incorporating recycled aluminum alloy materials to produce new aluminum alloys leads to decreased cost and time associated with producing primary aluminum as well as decreased carbon emissions (e.g., decreased global impact and specific carbon footprints). Recycled aluminum alloy materials, however, may be unsuitable for use in preparing high performance aluminum alloys as the recycled aluminum alloy materials may contain higher levels of certain undesirable elements, such as magnesium. For example, aluminum alloy parts used in a heat exchanger require high corrosion resistance among other properties. Therefore, aluminum alloy parts used in a heat exchanger have strict compositional limits to provide the desired properties. The strict bounds on composition and processing for many high performance aluminum alloy products severely limit the amounts and types of recycled aluminum alloy materials and process-related scraps that can be used. For example, recycled scrap may include certain elements in amounts that adversely affect the mechanical properties of an aluminum alloy and its corrosion resistance. For these reasons, it is impractical to use high amounts of recycled scrap in producing certain aluminum alloys, especially for heat exchangers that require strictly controlled aluminum alloy compositions and material properties.SUMMARY

[0004] Covered embodiments of the invention are defined by the claims, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings and each claim.

[0005] Provided herein are high magnesium content aluminum alloy products including an oxide coating for controlled atmosphere brazing. The aluminum alloy products described herein comprise a core layer comprising an aluminum alloy, wherein the core layer includes a first side and a second side, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer on at least one of the first side or the second side of the core layer. In some embodiments, the 7xxx series aluminum alloy of the core layer comprises AA7075 aluminum alloy. In some embodiments, the 3xxx series aluminum alloy of the core layer comprises AA3104 aluminum alloy. In some embodiments, the 3xxx series aluminum alloy of the core layer comprises AA3105 aluminum alloy. In some embodiments, the aluminum alloy products further comprise an anodic layer between the core layer and the oxide coating layer, wherein the anodic layer is formed by oxidation of the Mg content of the aluminum alloy after heat treatment. In some embodiments, a thickness ratio between the anodic layer and the oxide coating layer is at least 1 : 1. In some embodiments, the aluminum alloy comprises recycled aluminum alloy materials. In some embodiments, the recycled aluminum alloy materials comprise used clad aluminum alloy products comprising a mixture of 3xxx series aluminum alloys and 4xxx series aluminum alloys. Also provided herein are heat exchangers comprising the aluminum alloy products described herein.

[0006] In some embodiments, the oxide coating layer is deposited on at least one of the first side or the second side of the core layer in a flame pyrolysis process. In some embodiments, the oxide coating layer comprises an oxide compound including at least one of silicon, manganese, molybdenum, zirconium, or titanium. In some embodiments, the oxide coating layer has a thickness ranging from 10 nm to 250 nm. In some embodiments, the oxide coating layer is configured to corrode prior to the core layer. In some embodiments, the oxidecoating layer enables flux free brazing in a controlled atmosphere brazing process. In some embodiments, the oxide coating layer is a hydrophilic coating.

[0007] In some embodiments, the aluminum alloy product is an unclad aluminum alloy product. In some embodiments, the unclad aluminum alloy product is used as fin stock. In some embodiments, the aluminum alloy product is a clad aluminum alloy product that further comprises a cladding layer adjacent to at least one of the first side or the second side of the core layer, wherein the at least one cladding layer comprises a Ixxx series aluminum alloy or a 4xxx series aluminum alloy. In some embodiments, the at least one cladding layer comprises AA4343 aluminum alloy. In some embodiments, the at least one cladding layer comprises AA1045 aluminum alloy or AA1100 aluminum alloy.

[0008] In some embodiments, a method of producing an aluminum alloy product is provided. The method includes: casting an aluminum alloy to form a cast aluminum alloy product, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; homogenizing the cast aluminum alloy product; hot rolling the cast aluminum alloy product to produce a hot rolled product; cold rolling the hot rolled product to produce an aluminum alloy product; and depositing an oxide coating on at least one side of the aluminum alloy product to produce an aluminum alloy product having an oxide coating layer. In some embodiments, the method further includes heat treating the aluminum alloy product using a heat treatment temperature from 100° C to 485° C for 5 to 10 minutes. In some embodiments, the heat treatment step is configured to densify the oxide coating layer to increase the thickness of the oxide coating layer by at least 5 %. In some embodiments, the heat treatment step produces an anodic layer between a surface of the aluminum alloy product and the oxide coating layer. In some embodiments, the anodic layer is configured to corrode prior to the core layer. In some embodiments, the anodic layer is formed from the Mg content of the aluminum alloy product migrating to a surface of the aluminum alloy product to form an oxide compound.

[0009] In some embodiments, a method of producing an oxide coating layer using flame pyrolysis is provided. The method includes: combining an oxidizer and a combustible gas to form a gas mixture; igniting the gas mixture to form a premixed laminar flame; feeding a chemical precursor and a chemical additive into the premixed laminar flame to form an oxide coating flame, wherein the chemical precursor comprises a silicon-containing compound; and directing the oxide coating flame onto a metal substrate surface, wherein an oxide coating layer is deposited onto the metal substrate surface. In some embodiments, the method furtherincludes cleaning the metal substrate surface prior to the directing step. In some embodiments, the cleaning is performed by using a chemical etching process, an electrolytic cleaning process, or an ultrasonic cleaning process. In some embodiments, the silicon- containing compound comprises hexamethyldisiloxane (HMDSO), tetramethylsilane (TMS), tetraethoxysilane (TEOS), tri ethoxy silane, N-sec-butyl(trimethylsilyl)amine, 1,3 -diethyl- 1,1, 3,3, tetramethyldisilazane, methyl silane, pentamethyldisilane, tetraethyl silane, tetramethyldisilane, or a combination thereof.

[0010] In some embodiments, a method of forming a brazing product is provided. The method includes: providing one or more metal parts; providing an aluminum alloy product on or between the one or more metal parts to form an assembly; brazing the assembly in a controlled atmosphere to join the clad aluminum alloy product and the one or more metal parts to produce a brazed assembly; optionally applying a flux load before brazing; and cooling the brazed assembly. In some embodiments, the aluminum alloy product comprises a core layer including a first side and a second side, the core layer comprising a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer adjacent to at least one of the first side or second side of the core layer. In some embodiments, the aluminum alloy product comprises at least one cladding layer adjacent to the at least one oxide coating layer. In some embodiments, the assembly is brazed at a brazing temperature from 550° C to 620° C for 5 to 10 minutes.

[0011] Further aspects, objects, and advantages will become apparent upon consideration of the detailed description of non-limiting examples that follow.BRIEF DESCRIPTION OF THE FIGURES

[0012] FIG. 1 provides a schematic illustration of an example clad aluminum alloy product including a core layer adjacent to a first oxide coating layer and a second oxide coating layer.

[0013] FIG. 2 provides a schematic illustration of an oxide coating deposition system according to some embodiments.

[0014] FIG. 3 provides an electron micrograph image of an exemplary aluminum alloy product at a scale of 100 nm, the exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCh

[0015] FIG. 4 provides an electron micrograph image of an exemplary aluminum alloy product at a scale of 10 nm, the exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCh

[0016] FIG. 5 provides an electron micrograph image of an oxide coating layer of an exemplary aluminum alloy product depicted in FIG 4.

[0017] FIG. 6 provides an image of FIG. 5 after Fast Fourier Transform (FFT) image processing.

[0018] FIG. 7 provides an electron micrograph image of an exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCh.

[0019] FIG. 8 provides an image of elemental mapping (EDS) map of copper in an exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCE.

[0020] FIG. 9 provides an image of an EDS map showing the silicon, magnesium, and aluminum content of an exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCE.

[0021] FIG. 10 provides an EDS map showing the oxygen content of an exemplary aluminum alloy product having a core layer including an AA7075 aluminum alloy with a Mg content of 2.70 wt. % and an oxide coating layer including SiCh.DETAILED DESCRIPTION

[0022] Described herein are high magnesium content aluminum alloy products including a novel engineered oxide coating for controlled atmosphere brazing (CAB) that can be used as core aluminum alloys, clad aluminum alloy products, unclad aluminum alloy products (fmstock, brackets, etc.), and related methods of producing a brazeable product using aluminum alloys. The aluminum alloys products described herein comprise “recyclefriendly” aluminum alloys that can be used in a variety of applications, including, for example, as a core alloy in a clad aluminum product (e.g., a brazing sheet), that can replace core aluminum alloys produced from a high content of primary aluminum. By incorporating the oxide coatings described herein, the aluminum alloy products can tolerate higher amounts of magnesium (Mg) than conventional 3xxx series aluminum alloys (e g , used for brazing sheets), enabling the use of recycled aluminum alloy materials. Specifically, recycledaluminum alloy scrap including high amounts of Mg (e.g., greater than 0.20 wt.%) can be used to produce the aluminum alloy products described herein. The oxide coatings described herein prevent Mg migration to a surface of the aluminum alloys used in the aluminum alloy products. Accordingly, the oxide coatings described herein prevent magnesium oxide (MgO) from migrating to a surface of a core layer and disrupting brazing processes for the aluminum alloy products

[0023] Conventional aluminum alloys for use as core alloys (e.g., 3xxx series aluminum alloys) used in heat exchanger products cannot be produced with a high content of recycled aluminum alloy materials (e g., having high amounts of Mg) without sacrificing properties of the aluminum alloy products. However, there is a significant market need for aluminum alloys produced from recycled aluminum alloy materials to reduce carbon footprint. Besides factors like price and material properties, the recycled content of specific aluminum alloys is increasingly important for the automotive and non-automotive industries. Although there are aluminum alloys available on the market that can incorporate high amounts of recycled aluminum alloy materials that have wide chemistry windows for alloying elements (e g., Mg, Si, Cu, and Mn), these aluminum alloys cannot be considered for critical components (e.g., corrosion critical parts in heat exchangers). In particular, the Mg content in aluminum alloys for use as core alloys is limited because Mg migrates to the surface of the aluminum alloy to form a MgO film. MgO disrupts the flow of melting clad layer such that adequate fillets are not formed during the brazing cycle. Traditional fluxes (e.g., containing fluoride) were developed to prevent migration of Mg; however, only small amounts of Mg (e g., up to 0.05 wt. % Mg) can be tolerated in the core alloy.

[0024] The aluminum alloy products described herein incorporate core aluminum alloys having higher amounts of recycled aluminum alloy materials (e.g., high-Mg containing aluminum alloy scrap), as compared to conventional core aluminum alloys, and still maintain good mechanical properties, for example, for brazing applications. Specifically, the aluminum alloy products described herein include an oxide coating that surprisingly provides an aluminum alloy product having little to no Mg migration to a surface of the core aluminum alloys. In some embodiments, the core aluminum alloys described herein are 3xxx series aluminum alloys, 6xxx series aluminum alloys, or 7xxx series aluminum alloys having a Mg content of greater than 0.05 wt. %. Without being bound by theory, it was found that depositing the oxide coating on at least one side of the core aluminum alloy using a flame pyrolysis process prevents Mg content of the core aluminum alloys that forms MgO from migrating and disrupting the brazing process, thereby allowing higher amounts of Mg fromrecycled aluminum alloy materials. In some embodiments, Mg accumulation can occur between the oxide coating and the core aluminum alloy, creating an anodic layer that preferentially corrodes if the oxide coating is damaged, thereby increasing product life of the aluminum alloy products. Additionally, the oxide coating can enable flux free brazing during CAB. The combination of properties of the oxide coating described herein enables incorporating high magnesium content in the core aluminum alloy of unclad aluminum alloy products or clad aluminum alloy products.

[0025] The aluminum alloy products described herein possess a combination of properties that are suitable for the heat exchanger market (e.g., including the electrification of vehicles). In summary, the aluminum alloys described herein possess a combination of higher relative recycled content (e.g., 50 wt. % to 70 wt. %) that can be sourced from high-Mg containing materials to lower the carbon footprint of the aluminum alloy. The oxide coatings of the aluminum alloy products enable using aluminum alloys having a high-Mg content (e.g., greater than 0.05 wt. %) as core layers in the aluminum alloy products. By incorporating the oxide coatings in the aluminum alloy products, the aluminum alloys used in the core layer can be produced with high recycle rates while having added corrosion protection from the oxide coatings.Definitions and Descriptions:

[0026] The terms “invention,” “the invention,” “this invention,” and “the present invention” used herein are intended to refer broadly to all of the subject matter of this patent application and the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below.

[0027] In this description, reference is made to alloys identified by aluminum industry designations, such as “series” or “3xxx.” For an understanding of the number designation system most commonly used in naming and identifying aluminum and its alloys, see “International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys” or “Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot,” both published by The Aluminum Association.

[0028] As used herein, the meaning of “a,” “an,” or “the” includes singular and plural references unless the context clearly dictates otherwise.

[0029] As used herein, a plate generally has a thickness of greater than about 15 mm. For example, a plate may refer to an aluminum product having a thickness of greater than about 15 mm, greater than about 20 mm, greater than about 25 mm, greater than about 30 mm, greater than about 35 mm, greater than about 40 mm, greater than about 45 mm, greater than about 50 mm, or greater than about 100 mm.

[0030] As used herein, a shate (also referred to as a sheet plate) generally has a thickness of from about 4 mm to about 15 mm. For example, a shate may have a thickness of about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, or about 15 mm.

[0031] As used herein, a sheet generally refers to an aluminum product having a thickness of less than about 4 mm. For example, a sheet may have a thickness of less than about 4 mm, less than about 3 mm, less than about 2 mm, less than about 1 mm, less than about 0.5 mm, less than about 0.3 mm, or less than about 0.1 mm.

[0032] Reference is made in this application to alloy temper or condition. For an understanding of the alloy temper descriptions most commonly used, see “American National Standards (ANSI) H35 on Alloy and Temper Designation Systems.” An F condition or temper refers to an aluminum alloy as fabricated. An O condition or temper refers to an aluminum alloy after annealing. An Hxx condition or temper, also referred to herein as an H temper, refers to an aluminum alloy after cold rolling with or without thermal treatment (e.g., annealing). Suitable H tempers include HX1, HX2, HX3 HX4, HX5, HX6, HX7, HX8, or HX9 tempers. For example, the aluminum alloy can be strain hardened to various tempers, for example, H16, H18, or other HIX tempers.

[0033] Reference is made in this application to recycled content. The term “recycled content” incorporates, but is not limited to, what is typically called internal process waste or scrap but also different types of external scrap, for instance, post-consumer scrap, remelt scrap ingot (RSI), among others. Since primary aluminum (aside from the alloying elements and hardeners) is responsible for the majority of the Scope 3 emissions (described below), all types of recycled content inputs (whether they are internal or external scrap) contribute to more sustainable aluminum alloy products and support possible closed-loop material circularity (production) processes.

[0034] The following aluminum alloys are described in terms of their elemental composition in weight percentage (wt. %) based on the total weight of the alloy. In certain examples of each alloy, the remainder is aluminum, with a maximum wt. % of 0.15 % for the sum of the impurities.

[0035] As used herein, “controlled atmosphere brazing” or “CAB” refers to a brazing process which utilizes an inert gas atmosphere, for example, nitrogen or argon, in the brazing of the various alloy articles

[0036] As used herein, the meaning of “room temperature” can include a temperature of from about 15° C to about 30° C, for example about 15° C, about 16° C, about 17° C, about 18° C, about 19° C, about 20° C, about 21° C, about 22° C, about 23° C, about 24° C, about 25° C, about 26° C, about 27° C, about 28° C, about 29° C, or about 30° C.

[0037] All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g., 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10.Clad Aluminum Alloy Products

[0038] The terms “cladding,” “clad,” “cladding layer,” “clad layer,” and the related terms are used generally to refer to a relatively thin surface layer of clad aluminum alloy products. The terms “core,” “core layer,” and the related terms are used to refer to a relatively thicker layer of clad aluminum alloy products. In some examples, a clad aluminum alloy product (e.g., a clad sheet aluminum alloy) can have cladding layers on both sides of the core layer, in which case a core layer is an internal layer of the aluminum material. However, a clad aluminum alloy product (e.g., a clad sheet aluminum alloy) can alternatively have a cladding layer on only one side of the core layer, in which case the core layer can also be a surface. The core layer and cladding layer(s) typically have different chemical compositions. In some cases, a clad aluminum alloy product can have two different cladding layers with different compositions and properties.

[0039] It is to be understood that clad aluminum alloy products suitable for brazing applications do not necessarily contain only a core layer and one or two cladding layers. Clad aluminum alloy products can contain other layers (e.g., to form multilayer aluminum materials), some of which may be referred to as “interlayers,” “outer layers,” “liners,” and by other related terms. For example, clad aluminum alloy products can have 2, 3, 4, 5, 6 or more distinct layers, each having a certain function. More generally, clad aluminum alloy products can have as many layers as can be stacked and bonded together in one or more operations. In the commercial context, one possible limiting factor is the cost of production and / or scrap generated during production of clad aluminum alloy products, which can become too highwith the increased number of layers for the clad aluminum alloy products to be commercially viable. In the context of clad aluminum alloy products suitable for brazing applications, one or more of the cladding layers can be the portion of the product that melts during a braze cycle. A liner can be a layer that is not expected to melt during a braze cycle and may confer some other benefits, such as corrosion resistance or increased strength, to the clad aluminum alloy products A core can also include multiple layers, such as one or more interlayers on one or both sides of the main core layer.

[0040] In some embodiments, the clad aluminum alloy products include a core layer and at least one cladding layer with an oxide coating layer between the core layer and the at least one cladding layer. The oxide coating layer can be suitable for CAB processes. FIG. 1 provides a schematic of a clad aluminum alloy product 100 including a core layer 102 adjacent to a first oxide coating layer 104a and a second oxide coating layer 104b. The first oxide coating layer 104a is disposed between a first cladding layer 106a and the core layer 102. The second oxide coating layer 104b is disposed between a second cladding layer 106b and the core layer 102. In some cases, the first oxide coating layer 104a can be adjacent to and contact the first side of the core layer 102 to form a first interface (i.e., no layers intervene between the first oxide coating layer 104a and the first side of the core layer 102). The second oxide coating layer 104b can be adjacent to and contact the second side of the core layer 102 to form a second interface (i.e., no layers intervene between the second oxide coating layer 104b and the second side of the core layer 102). In some embodiments, the first oxide coating layer 104a and the second oxide coating layer 104b may include multiple layers. In some implementations, the oxide coating layers 104a-b can be used to couple the cladding layers 106a-b to the core layer 102. The first cladding layer 106a and the second cladding layer 106b may each comprise the alloy compositions described herein. In some embodiments, the core layer 102 is clad on only one side. In other embodiments, the core layer 102 is clad on both sides. In other embodiments, the core layer 102 is unclad and is intended for use with other clad aluminum alloy products.

[0041] The aluminum alloy products described herein can include 3xxx series aluminum alloys, 6xxx series aluminum alloys, or 7xxx series aluminum alloys having a Mg content greater than 0.05 wt. % as a core layer of an unclad aluminum alloy product or a clad aluminum alloy product. By including an oxide coating layer deposited on at least one side of the core layer, the aluminum alloy products can tolerate higher amounts of Mg than conventional aluminum alloy products affected by MgO formed from Mg migration to a surface of the core layer. As such, the aluminum alloys for the core layer can be producedfrom higher amounts of recycled aluminum alloys. For example, the aluminum alloy products may include a core layer comprising a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt %. The aluminum alloy products described herein can tolerate higher amounts of Mg and therefore can utilize clad aluminum alloy products as recycle material. In particular, the aluminum alloys described herein can be produced from more than 50 % of recycled aluminum alloy materials (e.g., mixed 3xxx / 4xxx series aluminum alloy process scrap).

[0042] The aluminum alloy products described herein can be used in industrial applications including sacrificial parts, filler parts, heat dissipation, packaging, and building materials. In some embodiments, the aluminum alloy products described herein can be employed in aluminum alloy parts for heat exchangers, including use with dissimilar metals and as / or with extruded components. Specifically, the aluminum alloy products described herein can form brazed products. Suitable cladding layers, oxide coating layers, and core layers for use in such aluminum alloy products are described below.Core Layer

[0043] Described below are aluminum alloy compositions that can be produced with a relatively high magnesium content. In some implementations, the relatively high magnesium content of the aluminum alloy composition can result from incorporating recycled aluminum alloy materials. In some embodiments, the aluminum alloy described herein can be used as a core layer, in combination with an oxide coating layer, to produce aluminum alloy products described herein. The aluminum alloy products described herein can include a cladding layer coupled to at least one side of the core layer to form a clad aluminum alloy product. In additional or alternative aspects, the aluminum alloy products described herein can be without a cladding layer to produce an unclad aluminum alloy product. The resulting aluminum alloy products are suitable for use in a variety of applications, including for instance, as use as a corrosion resistant brazing sheet package in manufacturing cold plates (e.g., cooling plates or battery cooling plates) for electric vehicle batteries.

[0044] In some embodiments, the aluminum alloy is a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content of at least 0.05 wt. %. For example, if the aluminum alloy is a 3xxx series aluminum alloy, the aluminum alloy can be an AA3104 aluminum alloy or an AA3105 aluminum alloy. As another example, if the aluminum alloy is a 7xxx series aluminum alloy, the aluminum alloy can be an AA7075 aluminum alloy. The aluminum alloys described herein exhibit good brazing performanceand corrosion resistance despite being produced from relatively high amounts of recycled aluminum alloys (e.g., Mg-containing aluminum materials) due to an oxide coating layer deposited on at least one side of the aluminum alloy.

[0045] In some embodiments, the aluminum alloy for the core alloy comprises a Mg content from 0.05 wt. % to 3.00 wt. % (e.g., from 0.10 wt. % to 3.00 wt. %, from 0.50 wt. % to 3.00 wt. %, from 1.00 wt. % to 3.00 wt. %, from 1.00 wt. % to 2.00 wt. %, from 1.50 wt. % to 3.00 wt. %, from 2.00 wt. % to 3.00 wt. %, or from 2.10 wt. % to 2.90 wt. %). In some embodiments, the aluminum alloy for the core alloy has a Mg content greater than 2.00 wt. %. In some embodiments, he aluminum alloy for the core alloy comprises a Mg content of 0.05 wt. %, 0.10 wt. %, 0.15 wt. %, 0.20 wt. %, 0.25 wt. %, 0.30 wt. %, 0.35 wt. %, 0.40 wt. %, 0.45 wt. %, 0.50 wt. %, 0.55 wt. %, 0.60 wt. %, 0.65 wt. %, 0.70 wt. %, 0.75 wt. %, 0.80 wt. %, 0.85 wt. %, 0.90 wt. %, 0.95 wt. %, 1.00 wt. %, 1.05 wt. %, 1.10 wt. %, 1.15 wt. %, 1.20 wt. %, 1.25 wt. %, 1.30 wt. %, 1.35 wt. %, 1.40 wt. %, 1.45 wt. %, 1.50 wt. %, 1.55 wt. %, 1.60 wt. %, 1.65 wt. %, 1.70 wt. %, 1.75 wt. %, 1.80 wt. %, 1.85 wt. %, 1.90 wt. %, 1.95 wt. %, 2.00 wt. %, 2.05 wt. %, 2.10 wt. %, 2.15 wt. %, 2.20 wt. %, 2.25 wt. %, 2.30 wt. %, 2.35 wt. %, 2.40 wt. %, 2.45 wt. %, 2.50 wt. %, 2.55 wt. %, 2.60 wt. %, 2.65 wt. %, 2.70 wt. %, 2.75 wt. %, 2.80 wt. %, 2.85 wt. %, 2.90 wt. %, 2.95 wt. %, or 3.00 wt. %.

[0046] In some examples, suitable alloys for use in the high magnesium content alloys described herein can be a 3xxx series aluminum alloy or a 7xxx series aluminum alloy. The 3xxx or 7xxx series aluminum alloy can be modified to include an amount of Mg as described above. In some embodiments, the core layer can be a 7xxx series aluminum alloy having a Mg content greater than 2.00 wt. %.

[0047] Suitable 3xxx series aluminum alloys for use as the core alloys described herein include, for example, AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203, AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A, AA3105, AA3105A, AA3105B, AA3007, AA3107, AA3207, AA3207A, AA3307, AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014, AA3015, AA3016, AA3017, AA3019, AA3020, AA3021, AA3025, AA3026, AA3030, AA3130, and AA3065.

[0048] Suitable 6xxx series aluminum alloys for use as the core alloys described herein include, for example, AA6101, AA6101A, AA6101B, AA6201, AA6201A, AA6401, AA6501, AA6002, AA6003, AA6103, AA6005, AA6005A, AA6005B, AA6005C, AA6105, AA6205, AA6305, AA6006, AA6106, AA6206, AA6306, AA6008, AA6009, AA6010, AA6110, AA6110A, AA6011, AA6111, AA6012, AA6012A, AA6013, AA6113, AA6014, AA6015, AA6016, AA6016A, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022,AA6023, AA6024, AA6025, AA6026, AA6027, AA6028, AA6031, AA6032, AA6033, AA6040, AA6041, AA6042, AA6043, AA6151, AA6351, AA6351A, AA6451, AA6951, AA6053, AA6055, AA6056, AA6156, AA6060, AA6160, AA6260, AA6360, AA6460, AA6460B, AA6560, AA6660, AA6061, AA6061A, AA6261, AA6361, AA6162, AA6262, AA6262A, AA6063, AA6063A, AA6463, AA6463A, AA6763, A6963, AA6064, AA6064A, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6181, AA6181A, AA6082, AA6082A, AA6182, AA6091, or AA6092.

[0049] Suitable 7xxx series aluminum alloys for use as the core alloys described herein include, for example, AA7019, AA7020, AA7021, AA7039, AA7072, AA7075, AA7085, AA7108, AA7108A, AA7015, AA7017, AA7018, AA7019A, AA7024, AA7025, AA7028, AA7030, AA7031, AA7035, AA7035A, AA7046, AA7046A, AA7003, AA7004, AA7005, AA7009, AA7010, AA7011, AA7012, AA7014, AA7016, AA7116, AA7122, AA7023, AA7026, AA7029, AA7129, AA7229, AA7032, AA7033, AA7034, AA7036, AA7136, AA7037, AA7040, AA7140, AA7041, AA7049, AA7049A, AA7149, AA7249, AA7349, AA7449, AA7050, AA7050A, AA7150, AA7250, AA7055, AA7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7175, AA7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7185, AA7090, AA7093, AA7095, and AA7099.

[0050] The core layer of the aluminum alloy product can utilize high amounts of recycled aluminum alloy scrap since the aluminum alloy can tolerate higher amounts of Mg than conventional aluminum alloys for core layers. For example, the aluminum alloy described herein can be produced from Mg containing aluminum alloy process scraps such as used clad aluminum alloy products containing a mixture of 3xxx series aluminum alloys and 4xxx series aluminum alloys.

[0051] For conventional core alloys, the Mg content in aluminum alloys can affect the type or amount of flux needed during the CAB process. However, conventional fluxes (e.g., fluxes containing fluoride) can only tolerate small amounts of Mg (e.g., up to 0.05 wt. %) at a surface of the core layer. In some embodiments, the oxide coating layer(s) of the aluminum alloy product can prevent Mg or Mg-containing compounds of the core layer from migrating to the surface of the core layer. Therefore, the aluminum alloys described herein can tolerate higher amounts of Mg and can be produced from recycled aluminum alloy materials. In additional or alternative embodiments, the oxide coating layer(s) can enable flux-free CAB to avoid problems caused by flux residues when applying flux.Cladding Layer

[0052] In some embodiments, the cladding layer is a Ixxx series aluminum alloy or 4xxx series aluminum alloy. Suitable Ixxx series aluminum alloys for use in the cladding layer described herein include, for example, AA1050, AA1060, AA1070, AA1100, AA1100A, AA1200, AA1200A, AA1300, AA1110, AA1120, AA1230, AA1230A, AA1235, AA1435, AA1145, AA1345, AA1445, AA1150, AA1350, AA1350A, AA1450, AA1370, AA1275, AA1185, AA1285, AA1385, AA1188, AA1190, AA1290, AA1193, AA1198, and AA1199. Suitable 4xxx series aluminum alloys for use in the cladding layer described herein include, for example, AA4004, AA4104, AA4006, AA4007, AA4008, AA4009, AA4010, AA4013, AA4014, AA4015, AA4015A, AA4115, AA4016, AA4017, AA4018, AA4019, AA4020, AA4021, AA4026, AA4032, AA4043, AA4043A, AA4143, AA4343, AA4643, AA4943, AA4044, AA4045, AA4145, AA4145A, AA4046, AA4047, AA4047A, AA4147, and modifications thereof.Recycled Aluminum Alloy Materials for Core Alloy

[0053] The aluminum alloy products described herein can tolerate high amounts of recycled aluminum alloy materials, thereby reducing greenhouse gas emissions associated with producing the aluminum alloy products. The impact of the impurities and / or alloying elements on the mechanical properties of the aluminum alloy products from incorporating the recycled aluminum alloy materials is reduced by providing an oxide coating layer on at least one side of the core layer of the aluminum alloy products. The oxide coating layer enables the aluminum alloy products to include recycled aluminum alloy materials with high Mg content (e.g., used clad aluminum alloy products including 3xxx / 4xxx series aluminum alloy) for producing aluminum alloy products that can still exhibit desirable properties.

[0054] The core layer of the aluminum alloy products described herein includes less primary aluminum than conventional 3xxx series aluminum alloys, 6xxx series aluminum alloys, or 7xxx series aluminum alloys, thereby lowering carbon emissions during production to reduce an overall carbon footprint. The aluminum alloy compositions described herein can include higher amounts of recycled aluminum alloy materials to reduce the overall carbon footprint of the aluminum alloy compared to conventional 3xxx series aluminum alloys. Aluminum alloys produced from recycled aluminum alloys with little to no primary aluminum minimize potential environmental impacts.

[0055] In some embodiments, the aluminum alloys described herein provide a composition that is well-suited for utilizing used clad aluminum alloy products as recyclematerial. Specifically, the aluminum alloys described herein can be produced from a substantial portion of used clad aluminum alloy products including a mixture of 3xxx and 4xxx series aluminum alloy. In some embodiments, used clad aluminum alloy products comprising a mixture of the 3xxx and 4xxx series aluminum alloy can be used as recycle material. As discussed herein, the aluminum alloy composition can utilize recycled aluminum alloy materials (e g , used clad aluminum alloy products) to produce the aluminum alloy due to the oxide coating layer that prevents migration of Mg or Mg-containing compounds. The aluminum alloy can be produced with higher volumes of recycled aluminum alloy materials and reduced amounts of primary aluminum In some embodiments, the aluminum alloy composition described herein can be produced from a mixture of 3xxx series and 4xxx series aluminum alloys. In some aspects, the aluminum alloys described herein include an amount of recycled aluminum alloy materials at or greater than 50 % (e.g., at or greater than 52 %, at or greater than 54 %, at or greater than 56 %, at or greater than 58 %, at or greater than 60 %, at or greater than 62 %, at or greater than 64 %, or at or greater than 65 %). As discussed above, in some aspects, the aluminum alloys described herein for use as the core layer of the aluminum alloy product are particularly well-suited to incorporate a mixture of 3xxx series aluminum alloy scrap and 4xxx series aluminum alloy scrap.

[0056] In some aspects, the aluminum alloys described herein include less than 50 % primary aluminum, e.g. less than 45 %, less than 40 %, less than 35 %, less than 30 %, less than 29 %, less than 28 %, less than 27 %, less than 26 %, less than 25 %, less than 24 %, less than 23 %, less than 22 %, less than 21 %, or less than 20 %. All percentages are expressed in wt. %.Oxide Coating Layer

[0057] In some embodiments, the oxide coating layer is deposited on at least one of a first side or a second side of the core layer of the aluminum alloy product in a flame pyrolysis process. The oxide coating layer can be suitable for CAB processes. An oxide coating deposition system can be used to deposit the oxide coating layer on the core layer. The oxide coating deposition system can include a gas mixture, a chemical precursor, and a chemical additive. In some cases, the chemical precursor and the chemical additive are gaseous in the oxide coating deposition system. The gas mixture used in the oxide coating deposition system can include an oxidizer and a combustible gas. The oxidizer serves as the oxygen source and can be, for example, air or oxygen. The combustible gas can include an alkane, an alkene, an alkyne, an alicyclic compound (e.g., a cycloalkane, a cycloalkene, or a cycloalkyne), aketone, an aromatic compound (e.g., a carbon-based aromatic compound or a heteroatomcontaining aromatic compound), an alcohol, an ether, an amine, an ester, an aldehyde, a saturated or unsaturated heterocyclic compound, any combination thereof, or any suitable combustion fuel source. Optionally, the combustible gas can be natural gas, methane, propane, or butane. The oxidizer and the combustible gas can be present in the gas mixture in a molar ratio of from about 1 : 1 to about 10:1 (e g , from about 3 : 1 to about 9: 1 or from about 6: 1 to about 10:1). For example, the molar ratio of the oxidizer and the combustible gas can be about 1: 1, about 1.5:1, about 2: 1, about 2.5:1, about 3:1, about 3.5: l, about 4:l, about 4.5:1, about 5:1, about 5.5: 1, about 6:1, about 6.5: 1, about 7:1, about 7.5: 1, about 8: 1, about 8.5: 1, about 9:1, about 9.5 : 1 , or about 10 : 1 , or anywhere in between.

[0058] The oxide coating deposition system described herein additionally can include a chemical precursor. The chemical precursor is gaseous and can be prepared, for example, by vaporizing a liquid chemical precursor (e.g., by vaporizing a chemical precursor that is liquid at room temperature, by vaporizing a solid chemical precursor that is dissolved or dispersed in a solvent, or by sublimating a solid chemical precursor) using, for example, a bubbling system or a controlled evaporator mixer or by aerosolizing a chemical precursor that is liquid at room temperature. In some embodiments, the chemical precursor can include a silicon- containing compound (e.g., silane, disilane, trisilane, tetrasilane, pentasilane, a siloxane, a silanol, chlorosilane, tetraethyl orthosilicate, silicon tetrachloride, dichlorosilane, trichlorosilane, difluorosilane, vinylsilane, dimethyldichlorosilane, hexamethyldisiloxane (HMDSO), methylsilane, dimethylsilane, trimethyl silane, tetramethylsilane (TMS), tetramethyldisilane, tetraethoxysilane (TEOS), triethoxysilane, N-sec- butyl(trimethylsilyl)amine, 1,3-diethyl-l, 1,3, 3, tetramethyl disilazane, pentamethyldisilane, tetraethylsilane, or any other suitable silicon-containing compound, including organic silicon- containing compounds and inorganic silicon-containing compounds). In additional or alternative embodiments, the chemical precursor can include a titanium-containing compound, a cobalt-containing compound, a chromium-containing compound, a molybdenum-containing compound, a nickel -containing compound, a copper-containing compound, a zirconium-containing compound, a tantalum-containing compound, a cerium- containing compound, a zinc-containing compound, or a tungsten-containing compound. One of more of these compounds can be used as the chemical precursor alone or in combination with the silicon-containing compound.

[0059] A chemical additive can also be present in the oxide coating deposition system. Optionally, the chemical additive can be gaseous or can be prepared, for example, byvaporizing a liquid chemical additive (e.g., by vaporizing a chemical additive that is liquid at room temperature or by vaporizing a solid chemical additive that is dissolved or dispersed in a solvent) or by aerosolizing a liquid chemical additive. In some cases, the chemical additive can be a liquid chemical additive that is vaporized using, for example, a bubbler system or a controlled evaporator mixer (CEM). In certain cases, the chemical additive can be a solid chemical additive that is sublimed to provide a gaseous chemical additive.

[0060] The chemical additive can be chosen according to the desired reaction product and surface properties for the metal substrate. Suitable chemical additives include, for example, adhesion promoters and / or corrosion inhibitors. Optionally, the chemical additives include chromates, molybdates, vanadates, antimonites, arsenates, tungstates, alumina nanoparticles, silica nanoparticles, chloride scavengers, or combinations thereof.

[0061] In certain aspects, the oxide coating layer includes an oxide compound having at least one of silicon, manganese, molybdenum, zirconium, or titanium (e.g., SiO?, TiO?, ZrO2, or a combination thereof). The oxide coating layer can have a thickness ranging from 10 nm to 250 nm. The oxide coating layer can enable the aluminum alloy product to tolerate relatively high levels of alloying elements from using high magnesium content aluminum materials. Conventional fluxes (e.g., including fluoride) used during CAB processes may limit the Mg content of the core layer to 0.05 wt. % to avoid excessive MgO formation at a surface of the aluminum alloy product that hinders fillet formation during the CAB processes. The oxide coating layer impedes the MgO content of the core layer from migrating to the surface of the aluminum alloy product, thereby preventing disruptions to the CAB processes. In some cases, the thickness of the oxide coating layer can be adjusted to ensure that the Mg content of the core layer is unable to reach the surface of the aluminum alloy product. Additionally, the oxide coating layer may enable flux free brazing in the CAB processes. In some implementations, the oxide coating layer can enable the aluminum alloy product to tolerate up to 0.50 wt. % Mg in the core layer. Additionally, the oxide coating layer provides added corrosion protection for the core layer of the aluminum alloy product, for example by corroding prior to the core layer. In certain aspects, the oxide coating layer is a hydrophilic coating that exhibit hydrophilic properties to aid with wetting.

[0062] Once the oxide coating layer is deposited on the core layer, a cladding layer can be positioned adjacent to the oxide coating layer to produce a clad aluminum alloy product. In some embodiments, an additional oxide coating layer can be deposited onto external surfaces (e.g., a surface of the cladding layer). Depositing the oxide coating layer can involve an immersion coating process, a roll-to-roll coating process, a spray coating process, or avacuum deposition process. Additionally, depositing the oxide coating layer can involve subjecting the final gauge product to flame pyrolysis. In some embodiments, depositing the oxide coating layer can further involve heat treating the final gauge product using a heat treatment temperature from 100° C to 485° C for 5 to 10 minutes. Heat treating the oxide coating layer can densify the oxide coating layer to increase a thickness of the oxide coating layer by at least 5 % (e g., at least 6 %, at least 7 %, at least 8 %, at least 9 %, at least 10 %, etc.).

[0063] In certain aspects, the heat treatment step can produce an anodic layer between a surface of the final gauge product and the oxide coating layer due to Mg accumulation. For example, the anodic layer can include MgO formed by oxidation of the Mg content in the core layer after the heat treatment step. In some cases, a first thickness of the oxide coating layer can be similar to a second thickness of the anodic layer. For example, a thickness ratio between the anodic layer and the oxide coating layer can be at least 1 : 1. In cases in which the oxide coating layer is damaged (e.g., perforated, scratched, etc.), the anodic layer formed from Mg accumulation can preferentially corrode instead of the final gauge product, thereby increasing product life of the final gauge product.Methods of Preparing and Processing

[0064] In certain aspects, the disclosed aluminum alloy product is a product of a disclosed method. Without intending to limit the disclosure, aluminum alloy product properties are partially determined by the oxide coating layer deposited during the preparation of the aluminum alloy product. In certain aspects, the method of preparation for the oxide coating layer of the aluminum alloy product may influence or even determine whether the aluminum alloy product will have properties adequate for a desired application.Casting

[0065] The alloy described herein can be cast using a casting method as known to those of skill in the art. For example, the casting process can include a direct chill (DC) casting process. The DC casting process is performed according to standards commonly used in the aluminum industry as known to one of skill in the art. The DC process can provide an ingot. Optionally, the ingot can be scalped before downstream processing. Optionally, the casting process can include a continuous casting (CC) process. In some embodiments, the ingot can be scalped after casting.

[0066] The cast aluminum alloy product can then be subjected to further processing steps. For example, the processing methods as described herein can include the steps of optional homogenization, preheating, hot rolling, cold rolling, and / or annealing.Preheating

[0067] The preheating step can include heating a cast aluminum alloy product as described herein to attain a preheating temperature of at least 350° C (e g., 360° C, 370° C, 380° C, 390° C, 400° C, 410° C, 420° C, 430° C, 440° C, 450° C, 460° C, 470° C, 480° C, 490° C, 500° C, 510° C, 520° C, 530° C, 540° C, 550° C, 560° C, 570° C, 580° C, 580° C, 590° C, 600° C, 610° C, 620° C, 630° C, or anywhere in between). For example, the cast aluminum alloy product can be heated to a temperature of from 350° C to 630° C, 360° C to 620° C, 375° C to 610° C, 400° C to 600° C, 410° C to 575° C, from 420° C to 550° C, from 440° C to 540° C, from 450° C to 530° C, or from 450° C to 480° C. In some cases, the heating rate to the preheating temperature can be 10° C / hour or greater, 20° C / hour or greater, 30° C / hour or greater, 40° C / hour or greater, 50° C / hour or greater, 60° C / hour or greater, or 70° C / hour or greater. In other cases, the heating rate to the preheating temperature can be from 10° C / min to 100° C / min (e.g., 10° C / min to 90° C / min, 20° C / min to 80° C / min, 30° C / min to 70° C / min, from 40° C / min to 65° C / min, from 45° C / min to 60° C / min, or from 50° C / min to 60° C / min).

[0068] Optionally, the cast aluminum alloy product is then allowed to soak (i.e., held at the indicated temperature) for a period of time at the preheating temperature range.According to one non-limiting example, the cast aluminum alloy product is allowed to soak for up to 30 hours (e.g., from 10 minutes to 30 hours, inclusively). For example, the cast aluminum alloy product can be soaked at a temperature from 450° C to 560° C (e.g., up to 480° C) for 10 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, or anywhere in between. In some embodiments, the cast aluminum alloy product is soaked at a preheating temperature from 480° C to 560° C for 5 hours to 7 hours.Homogenization

[0069] In some embodiments, the method may include an optional homogenization step. In some embodiments, the homogenization step can be used in lieu of the preheating step. Insome embodiments, the homogenization step can be used in combination with the preheating step. For example, the cast aluminum alloy product can be homogenized and then subjected to preheating.

[0070] The homogenization step can include heating a cast aluminum alloy product as described herein to attain a homogenization temperature of at least 500° C (e.g., 500° C, 510° C, 520° C, 530° C, 540° C, 550° C, 560° C, 570° C, 580° C, 580° C, 590° C, 600° C, 610° C, 620° C, 630° C, or anywhere in between). For example, the cast aluminum alloy product can be heated to a temperature of from 500° C to 630° C, 510° C to 615° C, 500° C to 575° C, 510° C to 600° C, or from 525° C to 625° C. In some cases, the heating rate to the homogenization temperature can be 10° C / hour or greater, 20° C / hour or greater, 30° C / hour or greater, 40° C / hour or greater, 50° C / hour or greater, 60° C / hour or greater, or 70° C / hour or greater. In other cases, the heating rate to the homogenization temperature can be from 10° C / min to 100° C / min (e.g., 10° C / min to 90° C / min, 20° C / min to 80° C / min, 30° C / min to 70° C / min, from 40° C / min to 65° C / min, from 45° C / min to 60° C / min, or from 50° C / min to 60° C / min).

[0071] The cast aluminum alloy product is then allowed to soak (i.e., held at the indicated temperature) for a period of time at the homogenization temperature range. According to one non-limiting example, the cast aluminum alloy product is allowed to soak for up to 30 hours (e.g., from 1 hour to 30 hours, inclusively). For example, the cast aluminum alloy product can be soaked at a temperature from 500° C to 630° C for 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, or anywhere in between.

[0072] In some embodiments, the cast aluminum alloy product is hot rolled directly after the cast aluminum alloy product reaches the preheating or homogenization temperature. For example, for an aluminum alloy product including a cladding layer comprising a 4xxx series aluminum alloy, the product may be hot rolled as soon as the product reaches the preheating or homogenization temperature to prevent Si migration to the core layer.Hot Rolling

[0073] In some embodiments, a hot rolling step can be performed following the casting step (e.g., in a CC process). In other embodiments, the hot rolling step can be performed following the homogenization step and / or preheating step. To perform the hot rolling step, the cast aluminum alloy product can be hot rolled at a temperature from 350° C to 560° C(e.g., from 375° C to 550° C, from 400° C to 540° C, from 425° C to 530° C, from 460° C to 520° C, or from 475° C to 520° C). For example, the hot rolling step can be performed at a temperature of 350° C, 360° C, 370° C, 380° C, 390° C, 400° C, 410° C, 420° C, 430° C, 440° C, 450° C, 460° C, 470° C, 480° C, 490° C, 500° C, 510° C, 520° C, 530° C, 540° C, 550° C, 560° C, or anywhere in between. In some embodiments, the hot rolling temperature ranges from 460° C to 520° C In some implementations, the hot rolling step can be performed in a hot rolling mill with one or more stands (e.g., a single stand, two stands, three stands, etc.). In examples in which the hot rolling mill includes multiple stands, the stands can be arranged in series.

[0074] In certain cases, the cast aluminum alloy product can be hot rolled to a thickness of from 2 mm to 15 mm (e.g., from 2.5 mm to 12 mm). For example, the cast aluminum alloy product can be hot rolled to a thickness of 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, or 15 mm. In certain cases, the cast aluminum alloy product can be hot rolled to a gauge greater than 15 mm (i.e., a plate). In other cases, the cast aluminum alloy product can be hot rolled to a gauge less than 4 mm (i.e., a sheet).Cold Rolling

[0075] Following the hot rolling step, an optional cold rolling step can be performed. The cold rolling step can include one or more cold rolling passes. In certain embodiments, the hot rolled product from the hot rolling step can be cold rolled to produce, for example, a thin- gauge shate or a sheet. In some embodiments, this thin-gauge shate or sheet is cold rolled to have a final gauge thickness ranging from 0.02 mm to 10.0 mm (e.g., from 0.04 mm to 1.0 mm or from 0.2 mm to 3 mm).

[0076] In some embodiments, the cold rolling step can include two more cold rolling steps. The two or more cold rolling steps can reduce the thickness successively to the final gauge thickness. Optionally, the method can further comprise intermittent and / or final annealing steps in between or after the cold rolling steps.Oxide Layer Deposition

[0077] In certain aspects, once the hot rolled product has been cold rolled to produce a final gauge product, an oxide coating layer can be deposited on at least one of a first side or a second side of the final gauge product. The oxide coating layer can be suitable for CAB processes. The final gauge product can be cleaned (e.g., in a cleaning process chamber) toremove residual oils and excessive metal oxide species from the surface(s) of the final gauge product. In some embodiments, cleaning the final gauge product can involve etching one or more surfaces of the final gauge product. Optionally, residual oils can be removed from a first surface and a second surface of the final gauge product (e.g., a top surface and a bottom surface can be cleaned). In some aspects, all surfaces of the final gauge product are cleaned (e.g., the top surface, the bottom surface, a first side, and a second side are cleaned). At least a first surface of the final gauge product is then engineered according to methods described herein.

[0078] Depositing the oxide coating layer can involve an immersion coating process, a roll-to-roll coating process, a spray coating process, or a vacuum deposition process. In some implementations, depositing the oxide coating layer can involve subjecting the final gauge product to flame pyrolysis. FIG. 2 depicts a schematic of an oxide layer deposition system 200 using flame pyrolysis as described herein. A metal substrate 210 (e.g., the final gauge product) is passed in direction 215 adjacent to a burner 220 such that at least one surface 225 of the metal substrate 210 contacts a laminar flame 230. Process gases are supplied through a primary supply line 240 connected to a manifold 250 capable of supplying a plurality of process gases via individual supply lines 255. The individual supply lines 255 and the primary supply line 140 can include gas flow control devices (e.g., a mass flow controller, a computer-controlled valve, or a ball valve). The individual supply lines 255 and manifold 250 can premix the process gases before feeding the process gases to the burner 220. The burner 220 can supply the laminar flame 230 for thin film deposition. In some cases, an exhaust system can be implemented to control atmospheric conditions of the oxide layer deposition system by extracting heat produced by the methods described herein. For instance, the exhaust system may be employed to control the laminar flame 230.

[0079] A flame pyrolysis reaction of the process gases can occur in the laminar flame 230 and can deposit an oxide coating layer 260 onto the at least one surface 225 of the metal substrate 210. In some embodiments, a gaseous chemical precursor and a gaseous chemical additive can be fed into the laminar flame 230 and combusted in the laminar flame 230 to form an oxide coating flame. In some cases, the gaseous chemical precursor and the gaseous chemical additive can be fed simultaneously into the laminar flame 230. In other cases, the gaseous chemical precursor and the gaseous chemical additive can be added to the laminar flame 230 in an alternating manner (e.g., a portion of the gaseous chemical precursor can be fed into the laminar flame 230 followed by a portion of the gaseous chemical additive, and the addition cycle can repeat). In some non-limiting examples, the oxide coating layer 260can be patterned. A patterned oxide coating layer can provide localized protection to the final gauge product.

[0080] A gas flow rate for the gaseous components added to the laminar flame 230 (e g , the gaseous chemical precursor, the gaseous chemical additive, or a combination of these) can impact deposition of the oxide coating layer 260 and, subsequently, the performance properties of the resulting aluminum alloy product. In some cases, the gas flow rate for the gaseous chemical precursor and / or for the gaseous chemical additive can be from about 500 milliliters per minute (mL / min) to about 5000 mL / min (e.g., from about 750 mL / min to about 4000 mL / min, from about 1000 mL / min to about 3500 mL / min, or from about 1500 mL / min to about 3000 mL / min). For example, the gas flow rate for the gaseous chemical precursor and / or for the gaseous chemical additive can be about 500 mL / min, about 600 mL / min, about 700 mL / min, about 800 mL / min, about 900 mL / min, 1000 mL / min, about 1100 mL / min, about 1200 mL / min, about 1300 mL / min, about 1400 mL / min, about 1500 mL / min, about 1600 mL / min, about 1700 mL / min, about 1800 mL / min, about 1900 mL / min, about 2000 mL / min, about 2100 mL / min, about 2200 mL / min, about 2300 mL / min, about 2400 mL / min, about 2500 mL / min, about 2600 mL / min, about 2700 mL / min, about 2800 mL / min, about 2900 mL / min, about 3000 mL / min, about 3100 mL / min, about 3200 mL / min, about 3300 mL / min, about 3400 mL / min, about 3500 mL / min, about 3600 mL / min, about 3700 mL / min, about 3800 mL / min, about 3900 mL / min, about 4000 mL / min, about 4100 mL / min, about 4200 mL / min, about 4300 mL / min, about 4400 mL / min, about 4500 mL / min, about 4600 mL / min, about 4700 mL / min, about 4800 mL / min, about 4900 mL / min, about 5000 mL / min, or anywhere in between.

[0081] After the step of feeding the gaseous components into the oxide coating flame, the oxide coating flame can be directed onto a surface 225 of the metal substrate 210. In some cases, the metal substrate 210 can be passed adjacent to the gas burner 220 of the oxide coating flame at a distance from the gas burner 220 to deposit a thin film layer (e.g., the oxide coating layer 260) onto the surface 225 of the metal substrate 210. In some cases, the metal substrate 210 can be passed through the oxide coating flame. A distance between the surface 225 of the metal substrate 210 and the burner 220 of the oxide coating flame can also be referred to herein as a frontal distance. The frontal distance can impact the structure of the oxide coating layer 260 deposited onto the metal substrate 210. The frontal distance can be controlled by mechanical controls, computer controls, pneumatic controls, hydraulic controls, or any suitable position control system on the burner. The frontal distance can be adjusted according to burner design and desired process parameters. The frontal distance can be from about 8 millimeters(mm) to about 40 mm from a face of the burner (e.g., from about 15 mm to about 35 mm, from about 20 mm to about 35 mm, or from about 25 mm to about 30 mm). In some cases, the frontal distance can be about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, about 20 mm, about 21 mm, about 22 mm, about 23 mm, about 24 mm, about 25 mm, about 26 mm, about 27 mm, about 28 mm, about 29 mm, about 30 mm, about 31 mm, about 32 mm, about 33 mm, about 34 mm, about 35 mm, about 36 mm, about 37 mm, about 38 mm, about 39 mm, about 40 mm, or anywhere in between.

[0082] In some examples, the reaction byproducts 270 of the flame pyrolysis reaction can include carbon monoxide, carbon dioxide, water vapor, silicon and / or silicate dust (not shown), and / or phosphate dust (not shown). Optionally, the oxide layer deposition system can simultaneously apply a first oxide coating layer on a first surface of the metal substrate 210 and a second oxide coating layer on a second surface of the metal substrate 210. In some implementations, a thickness of the oxide coating layer 260 can range from 10 nm to 250 nm.

[0083] In some embodiments, depositing the oxide coating layer can further involve heat treating the final gauge product using a heat treatment temperature from 100° C to 485° C for 5 to 10 minutes. Heat treating the oxide coating layer can densify the oxide coating layer to increase a thickness of the oxide coating layer by at least 5 % (e.g., at least 6 %, at least 7 %, at least 8 %, at least 9 %, at least 10 %, etc.). In certain aspects, the heat treatment step can produce an anodic layer between a surface of the final gauge product and the oxide coating layer due to Mg accumulation. In cases in which the oxide coating layer is damaged (e.g., perforated, scratched, etc.), the anodic layer formed from Mg accumulation can preferentially corrode instead of the final gauge product, thereby increasing product life of the final gauge product.

[0084] Once the oxide coating layer is deposited on the final gauge product, a cladding layer can be positioned adjacent to the oxide coating layer to produce a clad aluminum alloy product. In some embodiments, an additional oxide coating layer can be deposited onto external surfaces (e.g., a surface of the cladding layer).Methods of Brazing

[0085] The clad aluminum alloy products described herein are suitable for brazing applications. Accordingly, various brazing processes and technological steps can be suitably employed in the embodiments of the present disclosure. The clad aluminum alloy products can be brazed in an inert gas atmosphere. Any suitable inert gas may be employed including,for example, argon, helium, nitrogen, etc. The clad aluminum alloy products described herein are suitable for CAB. For the brazing cycle, the clad aluminum alloy products can be heated in a CAB furnace. In some embodiments, the aluminum alloys can be used in other joining processes (e.g., flame brazing, fluxed braze rings / shims, inductive heating, laser brazing, welding, adhesive bonding, etc.).

[0086] In some embodiments, the brazing process is carried out in a dry atmosphere with little or no oxygen in the atmosphere to produce a brazed product. In some embodiments, the brazing process is carried out in an inert atmosphere of nitrogen, argon, or helium. The brazing process can include heating the clad aluminum alloy products as described herein to attain a brazing temperature of at least 485° C (e.g., at least 490° C, at least 500° C, at least 510° C, at least 520° C, or anywhere in between). For example, the clad aluminum alloy product can be heated to a temperature of from 485° C to 620° C (e.g., from 485° C to 615° C, from 500° C to 620° C, from 500° C to 615° C, from 550° C to 615° C, or from 570° C to 620° C). In some cases, the heating rate to the brazing temperature can be 200° C / hour or less, 180° C / hour or less, 160° C / hour or less, 140° C / hour or less, 120° C / hour or less, 100° C / hour or less, 75° C / hour or less, 50° C / hour or less, 40° C / hour or less, 30° C / hour or less, 25° C / hour or less, 20° C / hour or less, 15° C / hour or less, or 10° C / hour or less. In other cases, the heating rate to the brazing temperature can be from 10° C / min to 200° C / min (e.g., 10° C / min to 175° C / min, 10° C / min to 150° C / min, 10° C / min to 100° C / min, from 20° C / min to 90° C / min, from 30° C / min to 80° C / min, from 40° C / min to 70° C / min, or from 50° C / min to 60° C / min). In some embodiments, the heating rate to peak temperature in the CAB furnace is less than 3 minutes.

[0087] In some embodiments, a method of manufacturing a brazing product, such as a heat exchanger, joined by brazing or an assembly of brazed components is provided. The method may include providing the components of which at least one is made from a clad aluminum alloy product described herein. The method may include assembling the components, such as corrugated fin stock material and other components such as tubes, into an assembly. The method may further include brazing the assembly without applying a brazing flux on the assembly of components. The whole assembly is brazed in a controlled inert gas atmosphere at a brazing temperature, typically at a temperature in a range of 485° C to 620° C for a period long enough for melting and spreading of a filler joining the various components (e.g., a dwell time of 1 to 10 minutes). In some embodiments, the dwell time may be up to 10 minutes (e.g., from 5 to 10 minutes, up to 9 minutes, up to 8 minutes, up to 7 minutes, up to 6 minutes, up to 5 minutes, up to 4 minutes, up to 3 minutes, up to 2 minutes,up to 1 minutes, any time in between). The oxygen content in the brazing atmosphere should be as low as reasonably possible, and is preferably below 100 ppm, and more preferably below 50 ppm, for example at 25 ppm or less The method further includes cooling of the brazed assembly, typically to below 100° C, e.g., to room temperature using, for example, blown air or any other suitable cooling medium.

[0088] Following brazing, the brazed product can be subj ected to a densification process. For example, the method may include heat treating the brazed product at a heat treatment temperature from 100° C to 485° C for up to 10 minutes (e.g., from 5 to 10 minutes, up to 9 minutes, up to 8 minutes, up to 7 minutes, up to 6 minutes, up to 5 minutes, up to 4 minutes, up to 3 minutes, up to 2 minutes, up to 1 minutes, any time in between). In some embodiments, the heat treatment step is configured to densify the oxide coating layer to increase the thickness of the oxide coating layer by at least 5 %. In some embodiments, the heat treatment step produces an anodic layer between a surface of the aluminum alloy product and the oxide coating layer.

[0089] In some embodiments, the method includes densifying the oxide layer a heat treatment temperature from 485° C to 620° C (e.g., from 485° C to 615° C, from 500° C to 620° C, from 500° C to 615° C, from 550° C to 615° C, or from 570° C to 620° C) for up to 10 minutes (e.g., from 5 to 10 minutes, up to 9 minutes, up to 8 minutes, up to 7 minutes, up to 6 minutes, up to 5 minutes, up to 4 minutes, up to 3 minutes, up to 2 minutes, up to 1 minutes, any time in between). In some embodiments, brazing and densification can be carried out in a single step. For example, the heat treatment temperature for densification can be the same or overlapping range as the brazing temperature such that brazing and densification can be carried out in a single step.

[0090] While metal parts such as aluminum alloy articles are described throughout the text, the methods and articles apply to any metal. In some examples, the metal part is aluminum, an aluminum alloy, magnesium, a magnesium-based material, titanium, a titanium-based material, copper, a copper-based material, steel, a steel-based material, bronze, a bronze-based material, brass, a brass-based material, a composite, a sheet used in composites, or any other suitable metal or combination of materials.Methods of Using

[0091] The aluminum alloy products and methods described herein can be used in industrial applications including sacrificial parts, heat dissipation, heating, ventilation, air conditioning and refrigeration, or packaging and building materials. The aluminum alloyproducts described herein can be used in various applications, for example, as fin stock for heat exchangers. In one example, the aluminum alloy products described herein are useful for high performance, light weight automotive heat exchangers. More generally, the aluminum alloys described herein can be used in motor vehicle heat exchangers such as radiators, condensers, heaters, intercoolers, charge air coolers, oil coolers, exhaust coolers, fuel coolers, cold plates (e g , cooling plates or battery cooling plates) and evaporators Cold plates are typically produced by brazing a bare aluminum flat sheet to a formed sheet with a clad liner on one side and possible a Ixxx or a 7xxx sacrificial liner on the other side (e.g., coolant channel side) As discussed above, the compositions and the processes for producing the aluminum alloy products described herein lead to aluminum alloy products possessing a combination of beneficial characteristics and properties that make it suitable for manufacturing cold plates, base plates, tubes, headers, manifolds, side supports or other parts of automotive or industrial heat exchangers. However, the uses and applications of the aluminum alloy products described herein are not limited to automotive or industrial heat exchangers and other uses are envisioned. The aluminum alloy products described herein can be used for manufacture of various devices employing heat exchangers and produced by brazing, such as devices employed in heating, ventilation, and air conditioning (HVAC).

[0092] The aluminum alloy products disclosed herein are suitable substitutes for metals conventionally used in indoor and outdoor HVAC units. As used herein, the meaning of “indoor” refers to a placement contained within any structure produced by humans with controlled environmental conditions. As used herein, the meaning of “outdoor” refers to a placement not fully contained within any structure produced by humans and exposed to geological and meteorological environmental conditions comprising air, solar radiation, wind, rain, sleet, snow, freezing rain, ice, hail, dust storms, humidity, aridity, smoke (e.g., tobacco smoke, house fire smoke, industrial incinerator smoke, wildfire smoke, etc.), smog, fossil fuel exhaust, bio-fuel exhaust, salts (e.g., high salt content air in regions near a body of salt water), radioactivity, electromagnetic waves, corrosive gases, corrosive liquids, galvanic metals, galvanic alloys, corrosive solids, plasma, fire, electrostatic discharge (e.g., lightning), biological materials (e.g., animal waste, saliva, excreted oils, vegetation), wind-blown particulates, barometric pressure change, and diurnal temperature change. Due to the oxide coating layer(s), the aluminum alloy products described herein provide better corrosion performance compared to conventional aluminum alloy products currently employed in heat exchanger applications.

[0093] The following examples will serve to further illustrate the present invention without, however, constituting any limitation thereof. On the contrary, it is to be clearly understood that resort may be had to various embodiments, modifications and equivalents thereof which, after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the invention. During the studies described in the following examples, conventional procedures were followed, unless otherwise stated. Some of the procedures are described below for illustrative purposes.Illustrations

[0094] Illustration 1 : An aluminum alloy product comprising: a core layer comprising an aluminum alloy, wherein the core layer includes a first side and a second side, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer on at least one of the first side or the second side of the core layer.

[0095] Illustration 2: The illustration of any preceding or subsequent illustration, wherein the 7xxx series aluminum alloy of the core layer comprises AA7075 aluminum alloy.

[0096] Illustration 3: The illustration of any preceding or subsequent illustration, wherein the 3xxx series aluminum alloy of the core layer comprises AA3104 aluminum alloy.

[0097] Illustration 4: The illustration of any preceding or subsequent illustration, wherein the 3xxx series aluminum alloy of the core layer comprises AA3105 aluminum alloy.

[0098] Illustration 5: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer is deposited on at least one of the first side or the second side of the core layer in a flame pyrolysis process.

[0099] Illustration 6: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer comprises an oxide compound including at least one of silicon, manganese, molybdenum, zirconium, or titanium.

[0100] Illustration 7: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer has a thickness ranging from 10 nm to 250 nm.

[0101] Illustration 8: The illustration of any preceding or subsequent illustration, further comprising an anodic layer between the core layer and the oxide coating layer, wherein the anodic layer is formed by oxidation of the Mg content of the aluminum alloy after heat treatment.

[0102] Illustration 9: The illustration of any preceding or subsequent illustration, wherein a thickness ratio between the anodic layer and the oxide coating layer is at least 1: 1.

[0103] Illustration 10: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer is configured to corrode prior to the core layer.

[0104] Illustration 11: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer enables flux free brazing in a controlled atmosphere brazing process.

[0105] Illustration 12: The illustration of any preceding or subsequent illustration, wherein the oxide coating layer is a hydrophilic coating.

[0106] Illustration 13: The illustration of any preceding or subsequent illustration, wherein the aluminum alloy comprises recycled aluminum alloy materials.

[0107] Illustration 14: The illustration of any preceding or subsequent illustration, wherein the recycled aluminum alloy materials comprise used clad aluminum alloy products comprising a mixture of 3xxx series aluminum alloys and 4xxx series aluminum alloys.

[0108] Illustration 15: The illustration of any preceding or subsequent illustration, wherein the aluminum alloy product is an unclad aluminum alloy product.

[0109] Illustration 16: The illustration of any preceding or subsequent illustration, wherein the unclad aluminum alloy product is used as fin stock.

[0110] Illustration 17: The illustration of any preceding or subsequent illustration, wherein the aluminum alloy product is a clad aluminum alloy product, and wherein the clad aluminum alloy product further comprises: a cladding layer adjacent to at least one of the first side or the second side of the core layer, wherein the at least one cladding layer comprises a Ixxx series aluminum alloy or a 4xxx series aluminum alloy.[oni] Illustration 18: The illustration of any preceding or subsequent illustration, wherein the at least one cladding layer comprises AA4343 aluminum alloy.

[0112] Illustration 19: The illustration of any preceding or subsequent illustration, wherein the at least one cladding layer comprises AA1045 aluminum alloy or AA1100 aluminum alloy.

[0113] Illustration 20: A heat exchanger comprising the aluminum alloy product of any preceding or subsequent illustration.

[0114] Illustration 21 : A method of producing an aluminum alloy product, the method comprising: casting an aluminum alloy to form a cast aluminum alloy product, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; homogenizing the cast aluminum alloy product; hot rolling the cast aluminum alloy product to produce a hot rolled product; cold rolling the hot rolled product to produce an aluminum alloy product; anddepositing an oxide coating on at least one side of the aluminum alloy product to produce an aluminum alloy product having an oxide coating layer.

[0115] Illustration 22: The illustration of any preceding or subsequent illustration, further comprising heat treating the aluminum alloy product using a heat treatment temperature from 100° C to 485° C for 5 to 10 minutes.

[0116] Illustration 23: The illustration of any preceding or subsequent illustration, wherein the heat treatment step is configured to densify the oxide coating layer to increase the thickness of the oxide coating layer by at least 5 %.

[0117] Illustration 24: The illustration of any preceding or subsequent illustration, wherein the heat treatment step produces an anodic layer between a surface of the aluminum alloy product and the oxide coating layer.

[0118] Illustration 25: The illustration of any preceding or subsequent illustration, wherein the anodic layer is configured to corrode prior to the core layer.

[0119] Illustration 26: The illustration of any preceding or subsequent illustration, wherein the anodic layer is formed from the Mg content of the aluminum alloy product migrating to a surface of the aluminum alloy product to form an oxide compound.

[0120] Illustration 27: A method of producing an oxide coating layer using flame pyrolysis, the method comprising: combining an oxidizer and a combustible gas to form a gas mixture; igniting the gas mixture to form a premixed laminar flame; feeding a chemical precursor and a chemical additive into the premixed laminar flame to form an oxide coating flame, wherein the chemical precursor comprises a silicon-containing compound; and directing the oxide coating flame onto a metal substrate surface, wherein an oxide coating layer is deposited onto the metal substrate surface.

[0121] Illustration 28: The illustration of any preceding or subsequent illustration, further comprising cleaning the metal substrate surface prior to the directing step.

[0122] Illustration 29: The illustration of any preceding or subsequent illustration, wherein the cleaning is performed by using a chemical etching process, an electrolytic cleaning process, or an ultrasonic cleaning process.

[0123] Illustration 30: The illustration of any preceding or subsequent illustration, wherein the silicon-containing compound comprises hexamethyldisiloxane (HMDSO), tetramethylsilane (TMS), tetraethoxysilane (TEOS), triethoxysilane, N-sec- butyl(trimethylsilyl)amine, 1,3-diethyl-l, 1,3, 3, tetramethyl disilazane, methylsilane, pentamethyldi silane, tetraethyl silane, tetramethyl di silane, or a combination thereof.

[0124] Illustration 31 : A method of forming a brazing product, the method comprising the steps of: providing one or more metal parts; providing an aluminum alloy product on or between the one or more metal parts to form an assembly, wherein the aluminum alloy product comprises: a core layer including a first side and a second side, the core layer comprising a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer adjacent to at least one of the first side or second side of the core layer; and brazing the assembly in a controlled atmosphere to join the clad aluminum alloy product and the one or more metal parts to produce a brazed assembly; optionally applying a flux load before brazing; and cooling the brazed assembly.

[0125] Illustration 32: The illustration of any preceding or subsequent illustration, wherein the aluminum alloy product comprises at least one cladding layer adjacent to the at least one oxide coating layer.

[0126] Illustration 33: The illustration of any preceding or subsequent illustration, wherein the assembly is brazed at a brazing temperature from 550° C to 620° C for 5 to 10 minutes.Example 1

[0127] Sample aluminum alloy products were tested to determine the properties of the aluminum alloy products described herein. An aluminum alloy product comprised a core layer comprising a AA7075 aluminum alloy having a Mg content ranging from 2.10 wt. % to 2.90 wt. %. The core layer was subjected to a flame pyrolysis process to deposit an oxide coating layer comprising SiCh on the surface of the core layer. A flame pyrolysis temper pretreatment was applied in F temper to the aluminum alloy product at a distance of 25 mm. The aluminum alloy product was subsequently heated to 485° C for 5 minutes.

[0128] FIG. 3 provides an electron microscopy image of the aluminum alloy product at a scale of 100 nm and FIG. 4 provides an electron micrograph image of the aluminum alloy product in closer detail at a scale of 10 nm. As depicted in FIG. 3, the aluminum alloy product includes a core layer of the AA7075 aluminum alloy with an oxide coating layer of SiOs deposited adjacent to a surface of the core layer. In particular, the SiO2 oxide coating layer is deposited in a uniform layer on the core layer. As depicted in FIG. 4, the SiO? oxide coating layer can be present as an amorphous solid.

[0129] FIG. 5 provides a high-resolution electron microscopy image of the oxide coating layer depicted in FIG. 4) and FIG. 6 provides an image of FIG. 5 after Fast FourierTransform (FFT) image processing. The electron microscopy image indicates that the oxide coating layer remains amorphous after heating. Both the electron microscopy image and FFT image processing can demonstrate that the oxide layer lacks the long-range order that is characteristic of a crystal.

[0130] Energy-dispersive X-ray spectroscopy (EDS) was performed on the aluminum alloy product to further analyze the composition of the aluminum alloy product FIG. 7 provides a scanning transmission electron microscopy image of the aluminum alloy product. FIG. 8 provides an EDS map indicating copper content of the aluminum alloy product. As depicted in FIG. 8, a copper-rich layer is present in an upper location of the aluminum alloy product. The copper-rich layer results from copper redeposition from the copper TEM sample grid during focused ion beam (FIB) milling in the sample preparation. Additionally, FIG. 8 depicts additional copper content below the copper-rich layer that can correspond to copper present in the core layer of the aluminum alloy product. FIG. 9 provides an EDS map indicating silicon, magnesium, and aluminum content of the aluminum alloy product. As depicted in FIG. 9, the Mg content of the core layer of the aluminum alloy product has accumulated as a separate layer between the SiO? oxide coating layer and the core layer of AA7075. Oxygen in ambient atmosphere can travel through the oxide coating layer to react with the Mg content to form MgO that can interfere with CAB processes. The oxide coating layer can hinder or prevent the MgO from reaching a surface of the aluminum alloy product, thereby preventing the MgO from interfering with the CAB processes. FIG. 10 provides an EDS map indicating oxygen content of the aluminum alloy product. In conjunction with FIG. 9, FIG. 10 indicates that both the Mg and Si at the surface of the aluminum alloy product are in oxide form.

[0131] All patents, publications and abstracts cited above are incorporated herein by reference in their entireties. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptions thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims.

Claims

WHAT IS CLAIMED IS:

1. An aluminum alloy product comprising: a core layer comprising an aluminum alloy, wherein the core layer includes a first side and a second side, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer on at least one of the first side or the second side of the core layer.2 The aluminum alloy product of claim 1, wherein the 7xxx series aluminum alloy of the core layer comprises AA7075 aluminum alloy.

3. The aluminum alloy product of claim 1, wherein the 3xxx series aluminum alloy of the core layer comprises AA3104 aluminum alloy.

4. The aluminum alloy product of claim 1, wherein the 3xxx series aluminum alloy of the core layer comprises AA3105 aluminum alloy.

5. The aluminum alloy product of claim 1, wherein the oxide coating layer is deposited on at least one of the first side or the second side of the core layer in a flame pyrolysis process.6 The aluminum alloy product of claim 1, wherein the oxide coating layer comprises an oxide compound including at least one of silicon, manganese, molybdenum, zirconium, or titanium.

7. The aluminum alloy product of claim 1, wherein the oxide coating layer has a thickness ranging from 10 nm to 250 nm.

8. The aluminum alloy product of claim 1, further comprising: an anodic layer between the core layer and the oxide coating layer, wherein the anodic layer is formed by oxidation of the Mg content of the aluminum alloy after heat treatment.

9. The aluminum alloy product of claim 1, wherein the oxide coating layer is configured to corrode prior to the core layer.

10. The aluminum alloy product of claim 1, wherein the oxide coating layer enables flux free brazing in a controlled atmosphere brazing process.

11. The aluminum alloy product of claim 1, wherein the oxide coating layer is a hydrophilic coating.

12. The aluminum alloy product of claim 1, wherein the aluminum alloy comprises recycled aluminum alloy materials.

13. The aluminum alloy product of claim 12, wherein the recycled aluminum alloy materials comprise used clad aluminum alloy products comprising a mixture of 3xxx series aluminum alloys and 4xxx series aluminum alloys.

14. The aluminum alloy product of any of claims 1-12, wherein the aluminum alloy product is an unclad aluminum alloy product.

15. The aluminum alloy product of claim 14, wherein the unclad aluminum alloy product is used as fin stock.

16. The aluminum alloy product of any of claims 1-12, wherein the aluminum alloy product is a clad aluminum alloy product, and wherein the clad aluminum alloy product further comprises: a cladding layer adjacent to at least one of the first side or the second side of the core layer, wherein the at least one cladding layer comprises a Ixxx series aluminum alloy or a 4xxx series aluminum alloy.

17. The aluminum alloy product of claim 16, wherein the at least one cladding layer comprises AA4343 aluminum alloy.

18. The aluminum alloy product of claim 16, wherein the at least one cladding layer comprises AA1045 aluminum alloy or AA1100 aluminum alloy.

19. A heat exchanger comprising the aluminum alloy product of any of claims 1-1220. A method of producing an aluminum alloy product, the method comprising:casting an aluminum alloy to form a cast aluminum alloy product, wherein the aluminum alloy comprises a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; homogenizing the cast aluminum alloy product; hot rolling the cast aluminum alloy product to produce a hot rolled product; cold rolling the hot rolled product to produce an aluminum alloy product, and depositing an oxide coating on at least one side of the aluminum alloy product to produce an aluminum alloy product having an oxide coating layer.

21. The method of claim 20, further comprising: heat treating the aluminum alloy product using a heat treatment temperature from 100° C to 485° C for 5 to 10 minutes.

22. The method of claim 21, wherein the heat treatment step is configured to densify the oxide coating layer to increase a thickness of the oxide coating layer by at least 5 %.

23. The method of claim 21, wherein the heat treatment step produces an anodic layer between a surface of the aluminum alloy product and the oxide coating layer.

24. The method of claim 23, wherein the anodic layer is configured to corrode prior to the aluminum alloy product.

25. The method of claim 23, wherein the anodic layer is formed from the Mg content of the aluminum alloy product migrating to the surface of the aluminum alloy product to form an oxide compound.

26. A method of producing an oxide coating layer using flame pyrolysis, the method comprising: combining an oxidizer and a combustible gas to form a gas mixture; igniting the gas mixture to form a premixed laminar flame; feeding a chemical precursor and a chemical additive into the premixed laminar flame to form an oxide coating flame, wherein the chemical precursor comprises a silicon- containing compound; and directing the oxide coating flame onto a metal substrate surface, wherein an oxide coating layer is deposited onto the metal substrate surface.

27. The method of claim 26, further comprising cleaning the metal substrate surface prior to the directing step.

28. The method of claim 27, wherein the cleaning is performed by using a chemical etching process, an electrolytic cleaning process, or an ultrasonic cleaning process.

29. The method of any of claims 26-28, wherein the silicon-containing compound comprises hexamethyldisiloxane (HMDSO), tetramethylsilane (TMS), tetraethoxysilane (TEOS), triethoxysilane, N-sec-butyl(trimethylsilyl)amine, 1,3-diethyl- l,l,3,3,tetramethyldisilazane, methylsilane, pentamethyldisilane, tetraethyl silane, tetramethyldisilane, or a combination thereof.

30. A method of forming a brazing product, the method comprising the steps of: providing one or more metal parts; providing an aluminum alloy product on or between the one or more metal parts to form an assembly, wherein the aluminum alloy product comprises: a core layer including a first side and a second side, the core layer comprising a 3xxx series aluminum alloy, 6xxx series aluminum alloy, or a 7xxx series aluminum alloy having a Mg content greater than 0.05 wt. %; and an oxide coating layer adjacent to at least one of the first side or second side of the core layer; and brazing the assembly in a controlled atmosphere to join the aluminum alloy product and the one or more metal parts to produce a brazed assembly; optionally applying a flux load before brazing; and cooling the brazed assembly.

31. The method of claim 30, wherein the aluminum alloy product comprises at least one cladding layer adjacent to the oxide coating layer.

32. The method of claim 30, wherein the assembly is brazed at a brazing temperature from 550° C to 620° C for 5 to 10 minutes.

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