Aqueous composition containing Zr, Mo, and acid-functional polymer for metal surface treatment

Abstract

The present invention relates to a method for treating at least one metal surface of a substrate, comprising at least the step of contacting said surface with an acidic aqueous composition (A), said acidic aqueous composition (A) having a pH value in the range of 2.5 to <5.0 and comprising Zr ions (a) in an amount ranging from 10 to 200 ppm, calculated as the metal, a component (b) which is at least one polymer (P) selected from poly(meth)acrylic acid and (meth)acrylic copolymers having carboxylic acid groups and mixtures thereof, and Mo ions (c) in an amount ranging from 0.5 to 10 ppm, calculated as the metal, wherein the relative mass ratio of Zr ions (a) to Mo ions (c) is in each case calculated as the metal, ranging from 40:1 to 7.5:1. The present invention also relates to the corresponding acidic aqueous composition (A) per se, to a method for using the acidic aqueous composition (A) for treating a metal surface, and to a substrate comprising a surface so treated.

Description

[Technical Field]

[0001] The present invention relates to a method for treating at least one metal surface of a substrate, comprising at least the step of contacting the surface with an acidic aqueous composition (A), wherein the acidic aqueous composition (A) has a pH value in the range of 2.5 to <5.0 and comprises Zr ions (a) in an amount in the range of 10 to 200 ppm calculated as metal, a component (b) which is at least one polymer (P) selected from poly(meth)acrylic acid and (meth)acrylic copolymers and mixtures thereof having a carboxylic acid group, and Mo ions (c) in an amount in the range of 0.5 to 10 ppm calculated as metal, wherein the relative mass ratio of Zr ions (a) to Mo ions (c) is in the range of 40:1 to 7.5:1 calculated as metal in each case, and the present invention relates to the corresponding acidic aqueous composition (A) itself, a method of using the acidic aqueous composition (A) for treating a metal surface, and a substrate including the surface thus treated. [Background technology]

[0002] Aluminum materials made from aluminum and / or aluminum alloys are typically subjected to pretreatment methods for rust prevention and adhesion promotion. These pretreatment methods generally begin with pickling of the aluminum material. Such pretreatment of aluminum materials is used, for example, for building structural elements made of aluminum and / or aluminum alloys in various indoor and outdoor locations, but also for vehicle parts made of aluminum and / or aluminum alloys, such as wheels. After the pretreatment, the pretreated aluminum material is usually further coated.

[0003] WO2010 / 100187A1 discloses a two-step method for treating metal surfaces, such as surfaces made of aluminum or aluminum alloys. In the first step, the surface is brought into contact with an aqueous composition containing silane / silanol / (poly)siloxane. In the subsequent second step, the surface is brought into contact with an aqueous composition containing a phosphonate / phosphonic acid or other phosphonic compound. Thus, a (poly)siloxane and phosphonate coating is continuously formed. Such conventional two-step methods are generally disadvantageous because they involve relatively high costs due to increased expenditure of time, energy, and labor.

[0004] Conventional aqueous solutions used in the pretreatment of aluminum materials are based on composite fluorides, such as titanium and / or zirconium composite fluorides, forming a chemical conversion coating on the surface before any further coatings are applied. Subsequently, a further aqueous solution containing a phosphonate compound is applied, making the pretreatment a two-step process. However, the use of such a two-step method is disadvantageous for the reasons mentioned above. Alternatively, the aqueous solution based on the composite fluoride may additionally contain a phosphonate compound so that the pretreatment as a whole is carried out in a one-step process. However, the use of phosphonates is undesirable from an environmental protection standpoint because phosphonates are considered pollutants. Furthermore, it is also disadvantageous from an economic standpoint due to wastewater regulations and the need to purify wastewater accordingly.

[0005] However, currently known one-step pretreatment methods using composite fluorides such as titanium and / or zirconium composite fluorides do not always yield satisfactory results in terms of adequate corrosion protection, particularly the occurrence of undesirable filamentous corrosion, and / or sufficient adhesion.

[0006] For example, US Patent No. 4921552 discloses a method for coating an aluminum material or an alloy thereof. The coating composition used for this purpose contains, among other things, a polyacrylic acid polymer and H2ZrF6. US Patent No. 4191596 discloses a further method for coating an aluminum material or an alloy thereof. The coating composition used for this purpose contains, among other things, a polyacrylic acid polymer or an ester thereof, and H2TiF6, HZrF 26 It contains at least one of H2TiF6 and HZrF. Furthermore, WO97 / 13588A1 discloses a method for coating the surface of a metal selected from aluminum and aluminum alloys, the method for coating the surface with H2TiF6, HZrF 26 The method includes contacting the surface with an aqueous acid solution containing at least one of HBF4 and H2SiF6. After a rinsing step, the surface is further coated with an aqueous polymer composition. Furthermore, WO2020 / 049132A1, WO2020 / 049134A1 and WO2019 / 053023A1 each relate to a method for treating at least one surface of a substrate, wherein the surface is at least partially made of aluminum and / or an aluminum alloy. Each of the methods includes contacting the surface with an aqueous composition, the aqueous composition containing, in particular, at least one linear polymer containing a phosphonic acid group.

[0007] Finally, WO2017 / 046139A1 discloses a method for pretreatment of a workpiece having an aluminum or aluminum alloy surface, the method comprising, among other things, the step of applying an acidic, chromium-free aqueous solution to the workpiece, the solution comprising Zr as a composite fluoride and Mo as molybdate. However, the solutions disclosed herein do not necessarily provide satisfactory results with respect to adequate corrosion protection, particularly with respect to the occurrence of undesirable filamentous corrosion, and / or sufficient adhesion properties, especially when a powder coating composition, such as a (meth)acrylic powder coating composition, is subsequently applied on a chemical conversion coating formed using the above solution.

[0008] Therefore, there is a need to provide a method for treating metal substrates, particularly substrates made at least partially of aluminum and / or aluminum alloys. This method allows for the formation of a single chemical conversion coating layer in a single step, is economically and environmentally advantageous, provides good corrosion resistance, and does not result in unfavorable adhesion properties when applying further coatings on the formed chemical conversion coating layer. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] WO2010 / 100187A1 [Patent Document 2] US Patent No. 4921552 [Patent Document 3] US Patent No. 4191596 [Patent Document 4] WO97 / 13588A1 [Patent Document 5] WO2020 / 049132A1 [Patent Document 6] WO2020 / 049134A1 [Patent Document 7] WO2019 / 053023A1 [Patent Document 8] WO2017 / 046139A1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] assignment Accordingly, it is an object underlying the present invention to provide a method for treating a metal substrate, in particular a substrate made at least partially of aluminum and / or an aluminum alloy, which method is capable of forming a single chemical conversion coating layer in a single step, in particular allows avoiding conventionally used phosphonate treatment steps, is advantageous both economically and environmentally, provides good rust prevention properties, and does not have any disadvantages in terms of adhesion properties when a further coating is applied onto the formed chemical conversion coating layer.

[0011] Solution This object is solved by the subject-matter of the claims of the present application and the preferred embodiments thereof disclosed herein, that is, by the subject-matter described herein. Means for Solving the Problems

[0012] A first subject-matter of the present invention is a method for treating at least one surface of a substrate, wherein said surface is at least partially made of at least one metal, in particular is at least partially made of aluminum and / or an aluminum alloy, and the method comprises at least step (1), namely (1) a step of bringing at least one surface of the substrate into contact with an acidic aqueous composition (A) comprising, wherein the acidic aqueous composition (A) has a pH value in the range from 2.5 to <5.0 and comprises (a) zirconium ions in an amount ranging from 10 to 200 ppm, calculated as metal, (b) at least one polymer (P) selected from poly(meth)acrylic acid having carboxylic acid groups, (meth)acrylic copolymers having carboxylic acid groups, and mixtures thereof, and (c) molybdenum ions in an amount ranging from 0.5 to 10 ppm, calculated as metal and comprises the relative mass ratio of zirconium ions (a) to molybdenum ions (c), calculated in each case as metal, ranges from 40:1 to 7.5:1.

[0013] A chemical conversion coating film is formed on the surface of the substrate through the contact process (1).

[0014] A further subject of the present invention is an acidic aqueous composition (A), which is used in the contact step of the method of the present invention as defined above.

[0015] A further subject of the present invention is a method of using the acidic aqueous composition (A) of the present invention for treating at least one surface of a substrate, wherein the surface is at least partially made of at least one metal, preferably at least partially made of aluminum and / or an aluminum alloy, and the method preferably provides corrosion protection to the surface and / or the substrate and / or improves the adhesion of a chemical conversion coating formed by the treatment of the surface to further coatings applied on the chemical conversion coating, in particular to further (meth)acrylic-based coatings, such as (meth)acrylic-based powder coatings.

[0016] A further subject of the present invention is a substrate comprising at least one surface, wherein the surface is at least partially made of at least one metal, preferably at least partially made of aluminum and / or an aluminum alloy, and the surface is treated by the method of the present invention and / or by the acidic composition (A) of the present invention.

[0017] Surprisingly, it has been found that the presence of a specific combination of polymer (P), zirconium ion (a), and molybdenum ion (c) as component (b) used in the present invention in composition (A) significantly improves the properties of the chemical conversion coating formed by the contact step (1), particularly its ability to act as an adhesion promoter for further coatings applied thereon.

[0018] Furthermore, surprisingly, it was found that the presence of a specific combination of polymer (P), zirconium ions (a), and molybdenum ions (c) as constituent components (b) used in the present invention in composition (A) significantly reduces the subsurface migration and / or diffusion of corrosion. In particular, filamentous corrosion was found to be significantly reduced.

[0019] Furthermore, remarkably, since the method of the present invention allows for the formation of a single chemical conversion coating layer in a single step, it has been found that the method can be carried out in less time, energy, and effort, and is therefore economically advantageous. In particular, by using the method of the present invention, conventionally used additional processing steps, such as phosphonate treatment steps, are not required. Moreover, the method of the present invention has been found to be environmentally advantageous because it does not require the presence of harmful components, such as chromium-containing compounds, particularly Cr(VI) ions, and / or phosphonates in the composition, and yet excellent adhesion and corrosion prevention properties are obtained.

[0020] Furthermore, it was found that undesirable yellowing of the formed chemical conversion coating layer can be avoided when Mo ions are used in the aqueous composition in amounts defined above and below, and when the Zr / Mo mass ratio defined above and below is used. [Modes for carrying out the invention]

[0021] Detailed description of the invention In the context of the present invention, the term "comprising" in relation to the method of the present invention, composition (A) (used in the present invention), and masterbatch of the present invention preferably means "consisting of." In this case, for example, with respect to composition (A) of the present invention, in addition to its essential components (components (a), (b), (c) and water), one or more of the other optional components described below may be contained in the composition. Any component may be present in each case in the preferred embodiments described below. The same applies to further subject matter of the present invention.

[0022] Method of the present invention The present invention relates to a method for treating at least one surface of a substrate, wherein the surface is at least partially made of at least one metal, in particular at least partially made of aluminum and / or an aluminum alloy, and the method comprises at least a contact step (1).

[0023] Preferably, the method of the present invention does not include any steps involving phosphonate treatment. More preferably, the method of the present invention does not include any other steps involving any treatment, and any further chemical coating films are applied to the substrate even though a chemical coating film is obtained after the contact step (1).

[0024] Preferably, the method of the present invention does not include any steps involving any treatment with chromium ions, such as Cr(VI) ions.

[0025] Base material At least one area of ​​the substrate surface is made of at least one metal, preferably aluminum and / or an aluminum alloy. Other examples of metals are different types of steel. The substrate surface may consist of different areas containing different metals and / or alloys. However, at least one area of ​​the substrate surface is preferably aluminum and / or an aluminum alloy. Preferably, the entire surface of the substrate is made of aluminum and / or an aluminum alloy.

[0026] More preferably, such a substrate is made of aluminum and / or an aluminum alloy, and even more preferably an aluminum alloy.

[0027] In the case of aluminum alloys, the alloy preferably contains more than 50% by mass of aluminum relative to the total mass of the alloy. The method of the present invention is particularly suitable for any aluminum alloy containing more than 50% by mass of aluminum, including but not limited to aluminum-magnesium alloys including AA5005, and aluminum-magnesium-silicon alloys including but not limited to AA6014, AA6060, and AA6063, cast alloys such as AlSi7Mg, AlSi9Mg, AlSi10Mg, AlSi11Mg, AlSi12Mg, and forged alloys such as AlSiMg. Aluminum-magnesium alloys including AA5005, and aluminum-magnesium-silicon alloys including AA6060 and AA6063 are commonly used in the field of aluminum finishing and / or in the processing of wheels and / or in other vehicle parts, such as electric vehicle parts, such as battery housings. However, this method is primarily suitable for all alloys in the so-called AA1000, AA2000, AA3000, AA4000, AA5000, AA6000, AA7000, and AA8000 series. A preferred example of the AA2000 series is AA2024. A preferred example of the AA7000 series is AA7075. AA2024 and AA7075 are commonly used in the aerospace industry.

[0028] The most preferred aluminum alloy is selected from the group consisting of aluminum-magnesium alloy, aluminum-magnesium-silicon alloy, aluminum-copper alloy, aluminum-zinc alloy, and aluminum-zinc-copper alloy.

[0029] The base material can be a wheel or other component, such as an automobile part, a battery housing, a workpiece, or an electric vehicle component including a coil. The use of a coil is described, for example, in WO2017 / 046139A1. In these cases, the base material is preferably made of an aluminum-magnesium alloy or an aluminum-magnesium-silicon alloy. The base material can be a component usable in the construction of an aircraft. In this case, the base material is preferably made of an aluminum-copper alloy or an aluminum-zinc alloy.

[0030] Contact process (1) Step (1) of the method of the present invention is a contact step, in which at least one surface of the substrate is brought into contact with an acidic aqueous composition (A).

[0031] The surface to be treated may be cleaned with an acidic, alkaline, or pH-neutral cleaning composition and / or etched before being treated with the acidic aqueous composition (A). The treatment procedure in step (1), i.e., "contact," may include, for example, spray coating and / or dipping coating procedures. Composition (A) may be applied to the surface by flooding, by roll coating, or manually by wiping or brushing.

[0032] The processing time, that is, the period during which the acidic aqueous composition (A) used in the surface treatment method according to the present invention is in contact with the surface, is preferably 15 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and most preferably 45 seconds to 5 minutes, for example, 1 to 3 minutes.

[0033] In the method of the present invention, the temperature of the acidic aqueous composition (A) used in the treatment is preferably 5 to 50°C, more preferably 15 to 45°C, and most preferably 25 to 40°C.

[0034] By performing step (1) of the method of the present invention, a chemical conversion coating film is formed on the surface of the substrate that was in contact with the acidic aqueous composition (A). Preferably, a coating layer is formed, and the coating layer has a coating mass determined by XRF (X-ray fluorescence spectroscopy) after drying. 0.5~100 mg / m² 2 More preferably 0.75 to 50 mg / m² 2 More preferably 1 to 40 mg / m² 2 More preferably 2 to 35 mg / m² 2 More preferably, 5-30 mg / m² 2 , especially 10-26 mg / m² 2Preferably, it contains zirconium ions and molybdenum ions (used as constituent components (a) and (c), each calculated as a metal).

[0035] Any further steps of the method of the present invention Before step (1), one or more of the following steps may be performed in this order: Process (A-1): A process of cleaning the surface of the substrate and optionally rinsing it afterward. Process (B-1): The surface of the substrate is subjected to acid pickling, i.e., etching, and then the surface of the substrate is rinsed. Step (C-1): A step of bringing the surface of the substrate into contact with an aqueous composition containing at least one mineral acid (the aqueous composition being different from composition (A)), or with an aqueous alkaline composition or a pH-neutral aqueous composition, and Step (D-1): A step of rinsing the surface of the substrate obtained after contact in step (C-1) and / or step (B-1).

[0036] Alternatively, steps (A-1) and (B-1) may be performed in a single step, which is preferable. Preferably, both steps (A-1) and (B-1) are performed.

[0037] Optional step (C-1) removes aluminum oxide, undesirable alloy components, skin, brush dust, etc., from the surface of the substrate, thereby activating the surface for the subsequent chemical conversion treatment in step (1) of the method according to the present invention. This step represents an etching step.

[0038] Preferably, at least one mineral acid in the composition of step (C-1) is sulfuric acid and / or nitric acid, more preferably sulfuric acid. The content of at least one mineral acid is preferably in the range of 1.5 to 75 g / l, more preferably in the range of 2 to 60 g / l, and most preferably in the range of 3 to 55 g / l. The composition used in step (C-1) preferably further comprises one or more metal ions selected from the group consisting of titanium, zirconium, hafnium ions, and mixtures thereof. In processing parts, the processing period with the composition of step (C-1) is preferably in the range of 30 seconds to 10 minutes, more preferably in the range of 40 seconds to 6 minutes, and most preferably in the range of 45 seconds to 4 minutes. The processing temperature is preferably in the range of 20 to 55°C, more preferably in the range of 25 to 50°C, and most preferably in the range of 30 to 45°C. In processing coils, the processing period is preferably in the range of 3 seconds to 1 minute, most preferably in the range of 5 to 20 seconds.

[0039] The rinsing step (D-1) and any rinsing that is part of step (A-1) are preferably carried out using deionized water or tap water. Preferably, step (D-1) is carried out using deionized water.

[0040] After performing the essential step (1) of the method of the present invention, one or more of the following steps may be performed in this order: Step (2): A step of rinsing the surface of the substrate obtained after contact in step (1). Step (3): A step of bringing the surface of the substrate obtained after step (1) or after any step (2) into contact with the same or a different aqueous acidic composition (B) as composition (A). Step (4): A step of rinsing the surface of the substrate obtained after contact in step (3), and Step (5): A step of drying the surface of the substrate obtained after contact in step (1), after rinsing in step (2), after contact in step (3), or after rinsing in step (4).

[0041] After step (1) of the method according to the present invention, the surface of the substrate obtained after contact in step (1) can preferably be rinsed with deionized water or tap water (optional step (2)). After any step (3) of the method according to the present invention, the surface of the substrate obtained after contact in any step (3) can preferably be rinsed with water (optional step (4)).

[0042] Rinsing steps (2) and (4) are performed to remove excess components, such as polymers (P) and / or destructive ions, that are optionally present in composition (A) used in step (1) and in any composition used in step (3) from the substrate.

[0043] In one preferred embodiment, the rinsing step (2) is performed after step (1). In another preferred embodiment, the rinsing step (2) is omitted. In both embodiments, an additional drying step (5) is preferably performed. The drying step (5) dries at least the chemical coating film present on the surface of the substrate to form a coating layer.

[0044] The aqueous composition (B) applied in any step (3) of the method according to the present invention may be, for example, a different composition from the one used in step (1), i.e., a different composition from composition (A) used in step (1), but is not necessarily required to be so; i.e., it can be the same as composition (A).

[0045] The surface of the substrate used in the present invention can be covered by further, i.e., subsequent coatings. Therefore, the method of the present invention can be further modified by at least one additional optional step, i.e., Step (6): A step of applying at least one coating composition to the surface of the substrate obtained after step (1) or after any of steps (2) to (5) to form a coating film on the surface that is different from the chemical conversion coating film obtained after step (1). It may contain.

[0046] The coating composition used in step (6) differs from compositions (A) and (B), and preferably contains at least one polymer suitable as a binder, which is different from polymer (P). Examples of such polymers different from polymer (P) include, in particular, polyester, polyurethane, epoxy-based polymers (epoxy resins) and / or (meth)acrylic copolymers and / or polyvinylidene fluoride (PVDF). Where applicable, these polymers are used in combination with crosslinking agents such as blocked polyisocyanates and / or aminoplast resins.

[0047] Preferably, step (6) is performed. The coating composition used in step (6) may be a powder coating composition. Alternatively, it may be a solvent-based or aqueous coating composition. Preferably, a powder coating composition is used. Any conventional powder coating composition may be used in this step. The coating composition used may be a primer coating composition or a clear coat composition in particular.

[0048] Preferably, the method of the present invention includes step (6) as an additional coating step, in which at least one coating composition is applied to the surface of the substrate obtained after the contact step (1), i.e., the surface of the substrate having a chemical coating layer as a result of performing step (1), to form at least one further coating layer on the surface. Optionally, a rinsing step (2) is performed after step (1) but before the coating step (6). Regardless of whether the optional rinsing step (2) is performed, it is preferable to perform a drying step (5) before the coating step (6).

[0049] Before applying further coatings in step (6), the treated surface is preferably rinsed to remove excess polymer (P) and any unwanted ions.

[0050] The subsequent coating can be applied wet-on-wet on the metal surface treated in the treatment method according to the present invention. However, it is also possible to dry the metal surface treated according to the present invention in step (5) before applying any further coatings.

[0051] Composition (A) used in step (1) of the method of the present invention The acidic aqueous composition (A) used in step (1) preferably does not contain any chromium ions, such as Cr(VI) cations.

[0052] The acidic aqueous composition (A) used in step (1) preferably does not contain any phosphonate anions.

[0053] In the context of the present invention, the term "aqueous" in relation to composition (A) means, preferably, that composition (A) contains at least 50% by mass, preferably at least 60% by mass, more preferably at least 70% by mass, particularly at least 80% by mass, and most preferably at least 90% by mass of water, based on the total content of the inorganic solvent, including the organic solvent and water. Thus, composition (A) may contain at least one organic solvent in addition to water (however, in an amount less than the amount of water present).

[0054] Preferably, the acidic aqueous composition (A) contains at least 50% by mass, preferably at least 60% by mass, more preferably at least 70% by mass, particularly at least 80% by mass, and most preferably at least 90% by mass of water, in each case being relative to its total mass.

[0055] The acidic aqueous composition (A) has a pH value in the range of 2.5 to <5.0. Preferably, the pH value is measured at room temperature (23°C). The pH value of the acidic aqueous composition is preferably in the range of 2.6 to 4.8, preferably 2.8 to 4.6, more preferably 3.0 to 4.4, even more preferably 3.1 to 4.3, particularly 3.2 to 4.2, and most preferably 3.2 to 3.8. If necessary, the pH can be adjusted, preferably using nitric acid, aqueous ammonia, and / or sodium carbonate.

[0056] The acidic aqueous composition (A) can be used as an immersion coating bath. However, as outlined above in relation to step (1), it can also be applied by substantially any conventional coating procedure, such as spray coating, roll coating, brushing, wiping, etc. Spraying is preferred.

[0057] The acidic aqueous composition (A) used in the present invention may contain further components including ions, as described in detail below. As used herein in reference to the raw material components of the acidic aqueous composition, the term "further components" means "in addition to the essential components (a), (b), (c) and water." Therefore, such "further" compounds including ions are distinct from the essential raw material components (a), (b), and (c).

[0058] The terms "component" and "component" as used herein are interchangeable.

[0059] The total amount of all components (constituent components) present in composition (A) of the present invention, when added together, is 100% by mass.

[0060] Composition (A) may be in the form of a dispersion or a solution. Preferably, it is a solution.

[0061] Preferably, the acidic aqueous composition (A) has a temperature in the range of 18 to 35°C, more preferably in the range of 20 to 35°C, and particularly in the range of 20 to 30°C.

[0062] Preferably, the acidic aqueous composition (A) is The zirconium ion is included as component (a) in an amount ranging from 15 to 150 ppm, more preferably from 16 to 125 ppm, even more preferably from 17 to 100 ppm, even more preferably from 18 to 75 ppm, even more preferably from 20 to 65 ppm, and even more preferably from 20 to 35 ppm, and in each case these amounts are calculated as metal. and / or (preferably and), The mixture contains molybdenum ions in an amount ranging from 1 to 8 ppm, more preferably from 1.5 to 6 ppm, even more preferably from 1.5 to 5 ppm, even more preferably from 1.5 to 4 ppm, even more preferably from 2.0 to 3.5 ppm, and even more preferably from >2 to 3 ppm, all of which are calculated as metals in each case.

[0063] The relative mass ratio of zirconium ions (a) to molybdenum ions (c) in composition (A), calculated as metals in each case, is in the range of 40:1 to 7.5:1.

[0064] Preferably, the relative mass ratio of zirconium ions (a) to molybdenum ions (c) is in the range of 35:1 to 8:1, more preferably 25:1 to 8.5:1, even more preferably 15:1 to 9:1, even more preferably 12.5:1 to 9.5:1, and even more preferably 12.5 to 10:1, calculated as metals in each case.

[0065] Zirconium ions as component (a) Composition (A) contains zirconium ions in an amount ranging from 10 to 200 ppm, calculated as a metal.

[0066] Preferably, the acidic aqueous composition (A) contains zirconium ions in an amount ranging from 15 to 150 ppm, more preferably from 16 to 125 ppm, even more preferably from 17 to 100 ppm, even more preferably from 18 to 75 ppm, even more preferably from 20 to 65 ppm, and even more preferably from 20 to 35 ppm, all of which are calculated as metals in each case.

[0067] Preferably, the amount of component (a) in composition (A) (in ppm) is less than the amount of component (b) (in ppm).

[0068] Preferably, a precursor metal compound is used to generate ions as component (a) in composition (A). Preferably, the precursor metal compound is water-soluble. The solubility is determined at a temperature of 20°C and atmospheric pressure (1.013 bar).

[0069] The content of component (a) can be monitored and determined by ICP-OES (inductively coupled plasma emission spectroscopy). The method is described in detail below.

[0070] Particularly preferred zirconium compounds are complex fluorides of these metals. The term "complex fluoride" includes single and multiple protonated forms, as well as deprotonated forms. It is also possible to use mixtures of such complex fluorides. A complex fluoride in the sense of the present invention is a zirconium complex formed in composition (A) by the coordination of a fluoride ion, for example, a fluoride anion, to a zirconium cation in the presence of water.

[0071] Furthermore, zirconium can also be added in the form of a zirconyl compound, for example, zirconyl nitride and zirconyl acetate, or zirconium carbonate or zirconium nitride, with the latter being particularly preferred.

[0072] However, preferably, the zirconium ion (a) is incorporated into composition (A) in the form of its composite fluoride.

[0073] Polymer (P) as component (b) Composition (A) contains at least one polymer (P), and the polymer (P) is selected from the group consisting of poly(meth)acrylic acid having carboxylic acid groups, (meth)acrylic copolymers, and mixtures thereof. Accordingly, the polymer (P) is selected from poly(meth)acrylic acid (which has carboxylic acid groups as is clear from the term "poly(meth)acrylic acid" itself), carboxylic acid group-containing (meth)acrylic copolymers, and mixtures thereof.

[0074] The polymer (P) is preferably dissolved in the acidic composition (A). Solubility is determined at a temperature of 20°C and atmospheric pressure (1.013 bar).

[0075] The polymer (P) is preferably present in composition (A) in an amount in the range of 50 to 2000 ppm, preferably in the range of 60 to 1500 ppm, more preferably in the range of 70 to 1000 ppm, even more preferably in the range of 80 to 750 ppm, still more preferably in the range of 90 to 650 ppm, even more preferably in the range of 100 to 600 ppm, still more preferably in the range of 105 to 500 ppm, still more preferably in the range of 125 to 400 ppm, still more preferably in the range of 135 to 300 ppm, and most preferably in the range of 150 to 250 ppm.

[0076] Preferably, the polymer (P) does not contain any phosphonic acid and / or phosphonate groups.

[0077] Preferably, the at least one polymer (P) has a weight average molecular weight (M wThe mass average molecular weight is in the range of 40,000 to 350,000 g / mol, preferably 50,000 to 340,000 g / mol, more preferably 60,000 to 330,000 g / mol, even more preferably 65,000 to 320,000 g / mol, even more preferably 70,000 to 310,000 g / mol, even more preferably 70,000 to 300,000 g / mol, and even more preferably 75,000 to 275,000 g / mol. The mass average molecular weight is determined by the method described in the "Method" section below.

[0078] Preferably, the polydispersity of the polymer (P) is greater than 2.0, and more preferably greater than 2.5. Preferably, the polydispersity is in the range of >1.0 to 4.0. The polydispersity is determined by the method described in the "Method" section below.

[0079] Polymer (P) has a carboxylic acid group. Polymer (P) is selected from poly(meth)acrylic acid and (meth)acrylic copolymers having a carboxylic acid group, and mixtures thereof. Preferably, polymer (P) is poly(meth)acrylic acid, more preferably polyacrylic acid.

[0080] In any case, polymer (P) is prepared using (meth)acrylic monomer.

[0081] The term "(meth)acrylic" means "acrylic" and / or "methacrylic." Similarly, "(meth)acrylate" means acrylate and / or methacrylate. The polymer (P) is preferably a "(meth)acrylic polymer" formed from "acrylic monomer" and / or "methacrylic monomer," but if the polymer (P) is a copolymer, it may further contain non-acrylic and non-methacrylic monomer units by using additional ethylenically unsaturated monomers such as vinyl monomer. Preferably, the backbone of the (meth)acrylic copolymer (P) is formed from more than 50 mol%, more preferably more than 75 mol%, of (meth)acrylic monomer.

[0082] Preferably, the polymer (P) is a (meth)acrylic copolymer and comprises a polymer backbone and at least one side chain having a carboxylic acid group bonded to the polymer backbone.

[0083] The polymer (P) is preferably a linear polymer. If the polymer (P) is a copolymer, the monomer units present in the polymer (P) can be statistically arranged in two or more blocks, or as a gradient along the polymer backbone of the polymer (P). Such arrangements can also be combined. Preferably, if the polymer (P) is a copolymer and can be prepared by conventional radical polymerization, it has a statistical distribution. If the polymer (P) is a block copolymer, it can preferably be prepared by controlled radical polymerization.

[0084] Preferably, the polymer (P) contains monomer units (s1) present in the polymer, each monomer unit (s1) containing at least one carboxylic acid group in an amount of 50 to 100 mol%, more preferably 75 to 100 mol%, even more preferably 90 to 100 mol%, and particularly 100 mol%, in each case relative to the total amount of all monomer units in the polymer (P), the sum of all monomer units present in the polymer (P) is 100 mol%. In the case of 100 mol%, the polymer (P) is a homopolymer composed entirely of monomer units (s1) present in the polymer, each containing a side chain (S1) containing at least one carboxylic acid group, which is most preferable.

[0085] The functional group (S1) of the side chain not only undergoes a crosslinking reaction when a further coating film is applied to the chemical conversion coating film obtained after step (1) of the method of the present invention, and the coating composition used to form the further coating film contains a suitable film-forming polymer and / or a crosslinking agent having a functional group reactive with the functional group (S1) of the side chain, but also ensures that the polymer (P) has sufficient solubility in water, and consequently in the aqueous composition (A).

[0086] Preferably, at least one monomer used to prepare polymer (P) is selected from the group preferably consisting of (meth)acrylic monomers having at least one COOH- group. Examples include acrylic acid and methacrylic acid. Alternatively or additionally, especially when polymer (P) is a copolymer, other carboxylic acid group-containing monomers such as maleic acid and / or maleic anhydride may be used in its preparation.

[0087] If polymer (P) is a copolymer, it may contain additional monomer units different from (m1). These may contain side chains containing OH- groups. Examples of monomers suitable for introducing such side chains include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 3-phenoxy-2-hydroxypropyl (meth)acrylate, glycerol mono(meth)acrylate, N-(2-hydroxypropyl)(meth)acrylamide, allyl alcohol, hydroxystyrene, hydroxyalkyl vinyl ethers, such as hydroxybutyl vinyl ether and vinylbenzyl alcohol.

[0088] Molybdenum ion as component (c) Composition (A) contains molybdenum ions in an amount ranging from 0.5 to 10 ppm, calculated as a metal.

[0089] Preferably, the acidic aqueous composition (A) contains molybdenum ions in an amount ranging from 1 to 8 ppm, more preferably from 1.5 to 6 ppm, even more preferably from 1.5 to 5 ppm, even more preferably from 1.5 to 4 ppm, even more preferably from 2.0 to 3.5 ppm, and particularly in the range of >2 to 3 ppm, where in each case these amounts are calculated as metals.

[0090] To prepare the aqueous composition (A), a molybdenum salt that is preferably water-soluble (at a temperature of 20°C and atmospheric pressure (1.013 bar)) is used. Preferably, the molybdenum ion (c) is incorporated into composition (A) in the form of at least one molybdate, preferably at least one ammonium molybdate.

[0091] Further optional components The acidic aqueous composition (A) used in the present invention preferably contains free fluoride. This occurs due to the presence of component (a), i.e., particularly when a Zr complex fluoride is present as component (a) in (A), but may also occur due to the presence of other optional components described below, or when they are present as alternatives. Preferably, the acidic aqueous composition (A) contains free fluoride ions in an amount in the range of 1 to 500 ppm, more preferably in the range of 1.5 to 200 ppm, even more preferably in the range of 2 to 100 ppm, and particularly in the range of 2.5 to 50 ppm. The free fluoride content is determined using a fluoride ion sensitive electrode by the method disclosed in the "Methods" section.

[0092] Optionally, aqueous composition (A) further comprises at least one metal cation selected from the group of metal cations of the 1st to 3rd subgroups (copper, zinc, and scandium group) and the 4th to 8th subgroups (titanium, vanadium, chromium, manganese, iron, cobalt, and nickel group) of the periodic table, including lanthanides, and the 2nd main group (alkaline earth metal group), lithium, bismuth, and tin. The metal cation is generally introduced in the form of its water-soluble compound, preferably as its water-soluble salt. Preferred cations are selected from the group consisting of cations of cerium and other lanthanides, chromium, iron, calcium, cobalt, copper, magnesium, manganese, nickel, niobium, tantalum, yttrium, vanadium, lithium, titanium, hafnium, bismuth, zinc, and tin. Such metal cations are different from components (a) and (c).

[0093] Optionally, the aqueous composition (A) further comprises at least one pH-adjusting substance, more preferably selected from the group consisting of nitric acid, sulfuric acid, methanesulfonic acid, acetic acid, aqueous ammonia, sodium hydroxide, and sodium carbonate, with nitric acid, aqueous ammonia, and sodium carbonate being preferred. Depending on the pH value of the acidic aqueous composition (A), the above compounds may be in their fully or partially deprotonated or protonated form.

[0094] Optionally, aqueous composition (A) further comprises at least one water-soluble fluorine compound. Examples of such water-soluble fluorine compounds are fluorides and hydrofluoric acid. In particular, such compounds are present in composition (A) when component (a) is not present in composition (A) in the form of a zirconium complex fluoride.

[0095] Optionally, the aqueous composition (A) further comprises at least one corrosion inhibitor. Examples include L-cysteine ​​and other amino acids, benzotriazoles, and mixtures thereof. Preferably, at least one corrosion inhibitor does not contain any metal ions of any kind.

[0096] Composition (A) of the present invention A further subject of the present invention is an acidic aqueous composition (A), which is used in the contact step (1) of the method of the present invention as defined above.

[0097] Any preferred embodiments relating to the method of the present invention described herein, the composition (A) used in the contact step (1) of the said method, and the components contained therein, particularly components (a), (b) and water, as well as any other components, are also preferred embodiments of the acidic aqueous composition (A) according to the present invention itself.

[0098] The master batch of the present invention A further subject of the present invention is a masterbatch, which is used to produce the acidic aqueous composition (A) of the present invention by diluting the masterbatch with water and adjusting the pH value as appropriate.

[0099] The methods of the present invention described herein as described herein, the composition (A) of the present invention used in the contact step (1) of the said method, and the components contained therein, particularly components (a), (b) and water, as well as any other components, and any preferred embodiments relating to the acidic aqueous composition (A) itself described herein are also preferred embodiments of the masterbatch of the present invention.

[0100] When a masterbatch is used to produce the acidic aqueous composition (A) according to the present invention, the masterbatch typically contains the raw material components of the acidic aqueous composition (A) to be produced in desired proportions, i.e., components (a), (b), and (c) in higher concentrations. Such a masterbatch is preferably diluted with water to the concentrations of the raw material components disclosed above to form the acidic aqueous composition (A). If necessary, the pH value of the acidic aqueous composition may be adjusted after diluting the masterbatch.

[0101] Of course, it is possible to further add any arbitrary components to the water used to dilute the masterbatch, or to add any arbitrary components after diluting the masterbatch with water. However, it is preferable that the masterbatch already contains all the necessary components.

[0102] Preferably, the masterbatch is diluted with water and / or aqueous solution in a ratio of 1:5,000 to 1:10, more preferably 1:1,000 to 1:10, most preferably 1:300 to 1:10, and even more preferably 1:150 to 1:50.

[0103] Method of use of the present invention A further subject of the present invention is a method of using the acidic aqueous composition (A) of the present invention for treating at least one surface of a substrate, wherein the surface is at least partially made of at least one metal, preferably at least partially made of aluminum and / or an aluminum alloy, and the method preferably provides corrosion protection to the surface and / or the substrate, and / or improves the adhesion of a chemical conversion coating formed by the treatment of the surface to any further coating applied on the chemical conversion coating.

[0104] The methods of the present invention described herein as described herein, the composition (A) used in the contact step (1) of the method, and any other preferred embodiments relating to the masterbatch of the present invention, the components contained in the masterbatch and composition, particularly components (a), (b) and water, as well as any other components, and the acidic aqueous composition (A) itself described herein, are also preferred embodiments of the methods of use of the present invention.

[0105] The base material of the present invention A further subject of the present invention is a substrate comprising at least one surface, wherein the surface is at least partially made of at least one metal, preferably at least partially made of aluminum and / or an aluminum alloy, and the surface is treated by the method of the present invention and / or by the acidic composition (A) of the present invention. The treatment of the present invention forms a chemical conversion coating film, which is then present on the substrate. Thus, the substrate of the present invention represents a coated substrate.

[0106] The methods of the present invention described herein as described herein, the composition (A) used in the contact step (1) of the method, and further, the masterbatch of the present invention, the components contained in the masterbatch and composition, in particular components (a), (b) and water, as well as any other components, and the acidic aqueous composition (A) described herein as described herein, and any preferred embodiments relating to the methods of use of the present invention are also preferred embodiments of the substrate of the present invention.

[0107] In particular, the coated substrate had a post-drying coating mass of 0.5-100 mg / m² determined by XRF (X-ray fluorescence spectroscopy). 2 More preferably 0.75 to 50 mg / m² 2 More preferably 1 to 40 mg / m² 2 More preferably 2 to 35 mg / m² 2 More preferably, 5-30 mg / m² 2 , especially 10-26 mg / m² 2 It has a coating layer which consists of zirconium ions and molybdenum ions (used as constituent components (a) and (c), each calculated as a metal).

[0108] method 1. Average molecular weight M w and M n decision Number average and mass average molecular weight (M n and M wEach of these is measured according to the following protocol: The sample is analyzed by SEC (size exclusion chromatography) with a MALS detector. The absolute molar mass is obtained at a selected dn / dC value equal to 0.1875 mL / g to obtain approximately 90% of the recovered mass. The polymer sample is dissolved in the mobile phase, and the resulting solution is filtered through a Millipore filter of 0.45 μm. The elution conditions are as follows: Mobile phase: H2O 100 vol%; 0.1 M NaCl, 25 mM NaH2PO4, 25 mM Na2HPO4; 100 ppm NaN3; flow rate: 1 mL / min; column: Varian Aquagel OH mixed H, 8 μm, 3 * 30 cm; Detection: RI (Agilent concentration detector) + MALLS (Multi-Angle laser light scattering) Mini Dawn Tristar + 290 nm UV; Sample concentration: approximately 0.5 mass% in mobile phase; Injection loop: 100 μL. Polydispersity P is obtained from M n and M w It can be calculated from the value.

[0109] 2. Determination of free fluorine content The free fluoride content is determined by a fluoride ion-selective electrode. The electrode is calibrated using at least three master solutions with known fluoride concentrations. A calibration curve is created as a result of the calibration process. This calibration curve is then used to determine the fluoride content.

[0110] 3. ICP-OES The amounts of certain elements in the sample to be analyzed, such as zirconium and molybdenum present as components (a) and (c), are determined using inductively coupled plasma atomic emission spectrometry (ICP-OES) according to DIN EN ISO 11885 (dated September 1, 2009). The sample is thermally excited in an argon plasma generated by a high-frequency electric field, and the light emitted by the electron transitions is visualized as spectral lines of the corresponding wavelengths and analyzed using an optical system. There is a linear relationship between the intensity of the emitted light and the concentration of the element in question. Before implementation, calibration measurements are performed as a function of the specific sample to be analyzed using known elemental standards (reference standards). This calibration can be used to determine the concentrations of unknown solutions, such as the amounts of titanium, zirconium, and hafnium.

[0111] 4. Cross-cut test according to DIN EN ISO2409 (06-2013) The adhesion strength of the coating on the substrate is confirmed using a cross-cut test in accordance with DIN EN ISO 2409 (06-2013). The cutter spacing is 2 mm. Evaluation is based on a characteristic cross-cut value ranging from 0 (very good adhesion) to 5 (very poor adhesion). This method is used to measure dry adhesion. Alternatively, the cross-cut test is performed after storing the sample in water at 63°C for 48 hours to determine wet adhesion. The cross-cut test may also be performed after exposure for up to 240 hours in a condensation climate test in accordance with DIN EN ISO 6270-2CH (modified versions of 09-2005 and 10-2007). Each test is performed three times, and the average value is determined.

[0112] 5. Filamentous rot (FFC) The determination of filamentous corrosion is used to confirm the corrosion resistance of the coating on the substrate. This determination is performed over a period of 672 hours in accordance with MBN10494-6, 5.5 (2016-03 edition). The maximum filament length (LF) and / or average subsurface filament corrosion (UF) [in mm] are measured.

[0113] 6. Copper-catalyzed acetate spray (CASS) test according to DIN EN ISO9227 (09-2012) The copper-catalyzed acetate spray test is used to determine the corrosion resistance of coatings on substrates. In accordance with DIN EN ISO9227 (09-2012), the sample to be analyzed is placed in a chamber to which a 5% general salt solution is continuously sprayed. The salt solution is mixed with acetic acid and copper chloride, respectively, at a controlled pH and a temperature of 50°C for a set period, e.g., 168, 240, or 264 hours. The spray mist deposits on the sample to be analyzed, covering it with a corrosive film of brine. If the coating of the sample to be investigated has been notched down to the substrate prior to the CASS test, the substrate will corrode along the notched lines during the CASS test, allowing the sample to be investigated for its subfilm corrosion level in accordance with DIN EN ISO4628-8 (03-2013). As a result of the progression of corrosion, the coating is more or less eroded during the test. The degree of erosion [in mm] is a measure of the coating's resistance. Each test is performed three times, and the average value is determined. This allows us to determine the average value (mean value) for both corrosion ("c" value) and delamination ("d" value). [Examples]

[0114] The following embodiments further illustrate the present invention, but should not be construed as limiting its scope.

[0115] 1. Preparation of acidic aqueous compositions 1.1 Several acidic aqueous compositions were prepared (1 L each). All aqueous compositions contained H2ZrF6 in amounts corresponding to the ppm value of zirconium calculated as a metal, as shown in Table 1 below. All aqueous compositions further contained ammonium heptamolybdate in amounts corresponding to the ppm value of molybdenum calculated as a metal, as shown in Table 1 below. Each composition further contained Sokolan® PA110S as a polymer, which is 250,000 g / mol of M w It was a commercially available polyacrylic acid having [the specified characteristic].

[0116] Table 1a summarizes the acidic aqueous compositions prepared in this manner.

[0117] [Table 1]

[0118] 1.2 As described in Section 1.1, several further acidic aqueous compositions were prepared using the same raw material components (1 L each), except that different volumes / pH values ​​were used.

[0119] Table 1b summarizes the acidic aqueous compositions prepared in this manner.

[0120] [Table 2]

[0121] 2. Pretreatment method An aluminum alloy substrate (substrate T1; AA5005) was used as the base material. A5505 is an aluminum-magnesium alloy substrate.

[0122] The substrate was cleaned using the commercially available product Gardoclean® S5201 / 1 (at 63°C for 3 minutes). Next, it was rinsed twice with tap water (30 seconds each). Then, an etching process was performed. Etching was carried out using a mixture of the commercially available products Gardacid® 4325 (containing nitric acid; 50 g / L; Chemetall GmbH) and Gardobond® Additive H7274 (containing fluorine; 7.5 g / L; Chemetall GmbH) (60 seconds). After etching, it was rinsed with tap water (30 seconds), followed by a rinse with deionized water (30 seconds).

[0123] Next, a contact step was performed, that is, the surface of the substrate was brought into contact with one of the acidic aqueous compositions described in items 1.1 and 1.2 above to form a chemical conversion coating layer on the surface of the substrate. The contact step was performed for 60 seconds in each case by spraying one of the acidic aqueous compositions onto the surface of the substrate. The acidic aqueous composition was heated to 25°C before spraying. As a reference example (RE), a conventional two-step contact pretreatment was performed: a commercially available aqueous composition (Gardobond® X4707) containing no polymers was used in the first contact step, followed by a second contact step using a commercially available phosphonate-containing aqueous solution (Gardobond® X4661) after rinsing.

[0124] Following the contact process, a drying process (15 minutes at 60-70°C) was performed after a period of air blowing.

[0125] Subsequently, a coating layer was applied to the chemically converted substrate T1. An acrylic coating material, specifically a commercially available acrylic powder coating material (PY1005 from FreiLacke), was used. The dry layer thickness of these coatings was in the range of 80–100 μm.

[0126] 3. Characteristics of the coated substrate Several properties of the coated substrate obtained by the method of the present invention described in item 2 above were investigated. These properties were determined by the test method described above. The results are shown in Tables 2a and 2b. Furthermore, the coating mass was measured by XRF.

[0127] [Table 3]

[0128] As is clear from Table 2a, when a one-step processing method was used and the aqueous composition of the present invention was used, excellent adhesion and rust prevention properties were obtained. The adhesion and rust prevention properties were significantly better than those of Reference Example RE.

[0129] [Table 4]

[0130] As is clear from Table 2b, when using a one-step processing method and the aqueous composition of the present invention, excellent adhesion and rust prevention properties were obtained. The adhesion and rust prevention properties were significantly better when using composition A5 than when using comparative example A4, in which the Mo ion content was too high and the Zr / Mo mass ratio was outside the range of 40:1 to 7.5:1. Furthermore, when using composition A4, an undesirable yellowish color was observed in the resulting coating layer. It was found that this undesirable yellowing was observed when the amount of Mo ions was too high or when the above-mentioned Zr / Mo mass ratio was not met.

Claims

1. A method for treating at least one surface of a substrate, wherein the surface is at least partially made of aluminum and / or an aluminum alloy, and the method comprises at least one step (1), i.e. (1) A step of bringing at least one surface of the substrate into contact with the acidic aqueous composition (A) to form a chemical conversion coating layer on the surface of the substrate. Includes, The acidic aqueous composition (A) has a pH value in the range of 2.5 to less than 5.0, and (a) Zirconium ions in an amount ranging from 10 to 200 ppm, calculated as a metal. (b) at least one polymer (P) selected from poly(meth)acrylic acid having a carboxylic acid group, (meth)acrylic copolymer having a carboxylic acid group, and mixtures thereof, and (c) Molybdenum ions in an amount ranging from 0.5 to 10 ppm, calculated as a metal. Includes, The relative mass ratio of zirconium ions (a) to molybdenum ions (c) is in the range of 40:1 to 7.5:1 when calculated as a metal in each case. A method wherein the polymer (P) does not contain any phosphonic acid and / or phosphonate groups.

2. The method according to claim 1, wherein the relative mass ratio of zirconium ions (a) to molybdenum ions (c) is in the range of 35:1 to 8:1 when calculated as a metal.

3. The aforementioned acidic aqueous composition (A) It contains zirconium ions in the range of 15 to 150 ppm, which are calculated as a metal. and / or, The method according to claim 1 or 2, comprising molybdenum ions in an amount ranging from 1 to 8 ppm, which is calculated as a metal.

4. The method according to any one of claims 1 to 3, wherein the acidic aqueous composition (A) has a pH value in the range of 2.6 to 4.

8.

5. The method according to any one of claims 1 to 4, wherein the acidic aqueous composition (A) has a temperature in the range of 18 to 35°C.

6. The method according to any one of claims 1 to 5, wherein the at least one polymer (P) has a mass-average molecular weight (Mw) in the range of 40,000 to 350,000 g / mol.

7. The method according to any one of claims 1 to 6, wherein the polymer (P) is poly(meth)acrylic acid.

8. The method according to any one of claims 1 to 7, wherein the polymer (P) is present in composition (A) in an amount ranging from 50 to 2000 ppm.

9. The method according to any one of claims 1 to 8, wherein the zirconium ion (a) is incorporated into composition (A) in the form of a composite fluoride.

10. The method according to any one of claims 1 to 9, wherein the molybdenum ion (c) is incorporated into composition (A) in the form of at least one molybdate.

11. The method according to any one of claims 1 to 10, wherein the acidic aqueous composition (A) contains free fluoride ions in an amount ranging from 1 to 500 ppm.

12. An acidic aqueous composition (A) as defined in any one of claims 1 to 11.

13. A method of using the acidic aqueous composition (A) according to claim 12 for treating at least one surface of a substrate, wherein the surface is at least partially made of aluminum and / or an aluminum alloy.

14. The method of use according to claim 13, wherein the method of use provides corrosion resistance to the surface and / or the substrate, and / or improves the adhesion between the chemical conversion coating formed by the treatment of the surface and a further coating applied on the chemical conversion coating.

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