Method for producing a material bond between an insert and cast material and intermediate product

Abstract

The invention relates to a method for producing a material-bonded connection between an insert (1) and a casting material (2), wherein a protective layer (3) is applied to a surface (1') of the insert (1), the insert (1) having the protective layer (3) is brought into contact with the casting material (2) in the form of a melt (2'), the protective layer (3) is removed by contact with the melt (2') so that the surface (1') of the insert (1) is exposed again, and the casting material (2) comes into direct contact with the surface (1') of the insert (1) and forms the material-bonded connection with this surface (1'). The invention also relates to an intermediate product for use in a casting process, wherein the intermediate product is formed from an element provided as an insert (1), wherein a protective layer (3) is arranged on a surface (1') of the element provided as an insert (1).

Description

Technical area

[0001] The invention lies in the field of foundry technology. It relates to methods for producing a material-to-material bond between an insert and casting material, in particular aluminum. It also relates to an intermediate product for use in a casting process. Background and technical problems

[0002] Due to its low density, high specific strength, and good natural corrosion resistance, aluminum offers extensive potential for lightweight construction. The material is used as a cast and wrought alloy, particularly in automotive body construction. Assembled aluminum constructions consisting of complex-shaped cast structures and simple sheet / profile structures joined together in a conventional manner are established. A casting-technologically realized connection is desirable, in which sheet and / or profile elements (= "cast parts," "inserts," or "inserts") are bonded to the cast structures, preferably directly during the casting process, by casting or encasing the inserts with the molten metal, melting their surface, and then forming a bonded connection.This concept is known in the industry as composite casting and is an effective way to create a connection between a cast part and another component (= insert) while avoiding additional joining operations. The insert can be made of identical, similar (e.g., aluminum insert in aluminum casting, steel insert in cast iron or cast steel, etc.), or dissimilar material. The connection between the cast part and insert can be achieved through force, form, or material bonding, as well as through combinations of these basic mechanisms.

[0003] The requirements for the connection vary depending on the intended use of the assembly to be manufactured, primarily in the transmission of forces, heat, and / or electrical energy. In all cases, but especially when heat or electrical energy is transferred, a material-to-material bond is preferred. Accordingly, the composite casting of molten aluminum material with solid aluminum semi-finished material as an insert – with the goal of a material-to-material bond – represents a challenge that has not yet been satisfactorily solved technically.

[0004] A problem here is the corrosion protection layer of aluminum oxide (Al 2 O 3 ) that forms naturally on aluminum surfaces even upon contact with small amounts of oxygen. A firmly adhering oxide layer forms, which, due to its high strength and a melting point of approximately 2,000°C, acts as a "barrier layer" on the insert to be cast and hinders the melting of the aluminum semi-finished product upon contact with the aluminum melt.

[0005] It is important to distinguish between casting processes with high and low temperature exposure during the casting and solidification phases. In so-called gravity or permanent mold casting, aluminum melt fills the casting mold in a slow flow. The melt can flow comparatively slowly along the insert and thus cause a comparatively high heat input into the insert. In addition, these processes usually involve casting relatively thick walls (up to several centimeters), which intensifies the effect of the heat input from the melt into the insert. Both effects can lead to the aluminum material of the insert softening or even melting, which makes the insert unstable and no longer offers a solid base for an oxide or other type of barrier layer. This can cause the layer to crack or break and detach from the insert.Furthermore, the barrier layer can be entrained by the flowing molten metal and washed into the component or onto its surface. The melted or melted semi-finished product of the insert now has direct contact with the molten metal and can form a material-tight bond. In die casting, on the other hand, the filling of the casting mold and thus the pouring or pouring around of the insert takes place comparatively quickly, within a few to approximately 100 milliseconds. Furthermore, the process is characterized by a more spraying, droplet-distributed filling of the mold rather than a laminar melt flow. This can comparatively reduce the flowing effect for heat transfer from the melt to the insert. Furthermore, die casting typically produces components with thin walls, between 2 and 10 mm, which means that less volume of molten metal is available for temperature transfer from the melt to the insert.Therefore, no technical solutions are known in the die-casting process that intend or enable the tearing and detachment of oxide layers on aluminum inserts. Improving the bonding, particularly in die-casting processes, is therefore one aspect of this application, but the advantages of the invention can also be applied to other casting processes. State of the art

[0006] DE 10 2020 206 009 A1 relates to a method for coating a component made of a base material, which has a cover layer, in particular a closed one, made of a first cover material, with a coating material. In order to achieve a good material-to-material bond between the base material of the component and the coating material, the coating material is applied to the component in the form of powder particles by means of a process gas stream by cold gas spraying, wherein the process gas stream is adjusted such that it contains both first powder particles, which, due to their speed, each remove a portion of the cover material, and second particles, which, due to their speed, experience deformation upon impact with the surface of the component and weld to the component surface, penetrating the oxide layer and creating a bond between the sprayed-on material and the insert.The new surface thus consists of the sprayed-on material, for which materials with a low oxidation tendency are selected, which also support the bond formation during casting. Especially in die casting, this process results in an intermediate layer between the casting and the insert, which differs in its properties from both materials and can negatively impact the overall component behavior.

[0007] EP 0 854 763 B1 addresses the issue of increasing the strength of the intermetallic bond between an engine component made of an aluminum-based alloy and a reinforcement made of austenitic cast iron. To this end, the reinforcement is annealed in a decarburizing atmosphere prior to the Alfin process, known in the prior art, in order to obtain an Alfin layer largely free of graphite flakes.

[0008] EP 0 498 719 A1 describes a two-stage coating process: applying an oxidation-resistant metal followed by a further layer, which is to be partially dissolved or dissolved during the aluminum casting process. The solution described ultimately aims to form a bond-forming layer between the insert and the casting material as an intermediate layer.

[0009] Other approaches (e.g., US Pat. No. 5,377,742 A, DE 19 736 790 A1) involve applying oxidation-inhibiting coatings to an aluminum insert. In this case, this coating is intended to not only inhibit oxidation but also act as a bond to the cast material.

[0010] Zinc or zincate coatings (US 5 293 923 A, DE 10 2007 026 005 A1) pursue the technological approach of deliberately leaving this coating as an adhesion promoter layer between the joining partners in the composite casting. Here, too, the formation of a bond-forming layer between the insert and the casting material is pursued as an intermediate layer.

[0011] Document US 5,273,099 A discloses a method for joining aluminum composite parts. A chemical film containing potassium and fluorine is formed on an aluminum element, or a flux containing potassium and fluorine is applied to an aluminum element. The coated aluminum element, together with a disposable pattern in a predetermined assembled state, is embedded in a mold containing molding sand. A molten aluminum alloy is then poured into the mold, forming an aluminum alloy casting.

[0012] Document US 4,643,241 A discloses a method for producing an aluminum composite material to be integrally formed by bonding aluminum or an aluminum alloy to an aluminum or aluminum alloy member formed in advance in a predetermined shape by the internal cooling method, etc. The method includes the steps of forming a chemical conversion coating of pentafluoroaluminate (K2AlF5) by bringing a solution containing potassium ions and fluorine ions into contact with the surface of the aluminum member.

[0013] Non-patent literature: Schwankl, M. (2017): Al-Al composite casting - Technological principles and materials characterization of the bonding of wrought aluminum alloys in aluminum die casting. Erlangen, FAU University Press, 2017. Pintore, M. (2020): Casting technology production and technological characterization of copper-aluminum layered composites. Munich, TUM University Press, 2021. Summary of the invention

[0014] A method for producing a material-to-material bond between a cast part and an insert, by which the above-mentioned deficiencies are at least partially remedied, comprises, for example, the features mentioned in claim 1.

[0015] The deficiencies are also remedied by an intermediate product for use in a casting process according to the independent claim.

[0016] Advantageous embodiments can be found in the dependent subclaims as well as the following description and the figures.

[0017] According to the application, the deficiencies mentioned at the outset can be remedied in particular by applying, after removal of a barrier layer on the insert, a protective layer on an insert which completely or at least partially prevents the re-formation of the barrier layer and which is designed as a "sacrificial layer".

[0018] In a method according to the application for producing a material-to-material bond between an insert and a casting material, a protective layer is applied to a surface of the insert. The insert, which has the protective layer, is brought into contact with the casting material in the form of a melt. The protective layer is removed by contact with the melt, so that the surface of the insert is exposed again. The casting material comes into direct contact with the surface of the insert. The casting material forms the material-to-material bond with this surface.

[0019] An intermediate product according to the application for use in a casting process is formed from an element intended as an insert with a protective layer arranged on a surface of the element intended as an insert.

[0020] In the process or in the intermediate product, the surface of the insert on which the protective layer is applied is, for example, oxide-free or low-oxide. Aluminum, in particular, is prone to oxidation in process-relevant atmospheres. Therefore, inserts often initially have an oxide layer as a barrier layer. This barrier layer is then removed to expose the surface of the purest possible non-oxidized aluminum ("core material" or "insert material"), which is later intended to form a direct, integral bond with the melt.

[0021] However, other types of barrier layers are also conceivable, such as hydroxide layers. According to the application, inserts should also be free of other types of barrier layers in a broader sense that would hinder a direct, material-to-material bond between the core material and the melt.

[0022] As can be seen from these explanations, a direct material-to-material connection between the insert material or core material and the casting material is sought, in particular without a connection-forming layer (intermetallic phase or similar) arranged in between.

[0023] The barrier layer can be removed in a preparatory step of the process, for example, by mechanical ablation, galvanic treatment, laser processing, or plasma treatment. After removal of the barrier layer, the protective layer is applied, which primarily protects against further oxidation.

[0024] The protective layer can be, for example, a sol-gel layer (preferably containing silicon) and / or a plasma polymer layer (preferably containing silicon) and / or synthetic resin and / or epoxy resin and / or a polyelectrolyte multilayer (PEM) and / or a self-assembling monolayer (SAM) and / or polymer layer (which preferably contain nitrogen and / or sulfur and / or phosphorus) and / or metallic layer (which have been deposited by means of a brewing process and / or alternative electroplating processes and / or).

[0025] The protective layer is preferably applied to the insert immediately after the possible removal of the barrier layer and covers the reactive surface of the insert. The protective layer can prevent further reaction with the process-relevant atmosphere.

[0026] The removal of the barrier layer and / or application of the protective layer preferably takes place in a protective environment protected from atmospheric oxygen, for example, in an inert gas such as argon or within a liquid, e.g., aqueous (slightly acidic pH ≤ 4 or alkaline pH ≥ 10). Both steps preferably take place in the same environment.

[0027] The removal of the barrier layer and / or application of the protective layer is carried out using inline and / or online monitoring, preferably using optical, chemical, or electrochemical methods. This monitoring serves to ensure the quality of the insert's surface properties.

[0028] The insert, including the protective layer, is subjected to a casting process.

[0029] During a casting process, the reactive surface of the insert is released again so that a melt can come into contact with the barrier-free or barrier-poor surface of the insert and the formation of a material bond is enabled.

[0030] For example, the insert with the protective coating is brought into contact with the casting material in the form of a molten mass. The insert can be completely surrounded by the molten mass, for example. Alternatively, the surface of the insert can only come into contact with the molten mass in certain areas.

[0031] The protective layer is preferably removed by contact with the melt, so that the surface of the insert is exposed again.

[0032] This can be achieved, for example, by the melt acting on the protective layer in such a way that it decomposes, and / or evaporates, and / or detaches, and / or washes away, and / or alloys with the protective layer. In an exemplary embodiment of the method, the components are selected such that the melting, vapor, or decomposition points of the protective layer are below the solidus temperature of the core material of the insert.

[0033] The present application also discloses methods in which a substance, preferably containing chloride or fluoride, is applied to the barrier layer. This substance, during the casting process, particularly under heat, leads to a chemical decomposition of the barrier layer, thus exposing the surface of the insert, which comes into contact with the melt in situ before reoxidation of the surface of the insert occurs. The barrier layer to which the substance was applied can be decomposed, evaporated, detached, and / or washed away, for example, by exposure to the melt. The applicant reserves the right to claim such embodiments.

[0034] The melt is preferably an aluminum melt. However, the melt can also be an aluminum alloy and contain, for example, silicon and / or zinc and / or copper and / or magnesium. The melt can also be zinc, magnesium, copper, iron or steel, nickel, titanium, or another metallic element, as well as alloys based on the respective elements. The melt, especially aluminum melt, has a typical melting temperature during casting that depends on the alloy; for aluminum alloys, this is approximately in the range between 550 and 850 °C.

[0035] The melt can then come into direct contact with the surface of the insert that is free of or has little barrier layer, and finally the casting material can form a bond with this surface.

[0036] The insert may, for example, comprise aluminum. In particular, it may be made of aluminum or an aluminum alloy. Alternatively or additionally, the insert may also comprise or consist of magnesium and / or iron or steel and / or copper and / or titanium and / or zinc, or an alloy of these materials.

[0037] The invention can be used with particular advantage for aluminum-aluminum connections, ie the melt and insert are made of aluminum.

[0038] The melt can be brought into contact with the insert, in particular the surface of the insert, in particular during a die-casting process.

[0039] In one embodiment of the method, it can be provided that the insert, together with the protective layer on its surface, is preheated. The insert with the protective layer can then be brought into contact with the melt in a heated state. This can, for example, promote the dissolution or detachment process of the protective layer and / or the formation of the integral bond.

[0040] In one embodiment of the method, a subsequent heat treatment is performed on the insert and the cast material arranged thereon. In particular, the integral bond between these two components of the composite component can be created and / or promoted and / or refined by the heat treatment. This means that it is possible for the integral bond to be created, promoted, or refined subsequently, whereby the process for forming the integral bond does not take place, does not take place sufficiently, or is not completed during the casting process, but is initiated and / or completed in the post-processing step.

[0041] An intermediate product for use in a casting process is formed from an element provided as an insert, wherein a protective layer according to the application is arranged on a surface of the element provided as an insert.

[0042] The protective layer is, for example, in direct contact with the surface of the element intended as an insert, which is free of a barrier layer and in particular is oxide-free or low in oxide.

[0043] It is understood that the aspects described in the context of the process with regard to the insert and / or the protective layer can also be claimed for the intermediate product and vice versa.

[0044] Exemplary embodiments of the invention will now be explained with reference to the attached figures. Short description of the characters

[0045] The figures show Fig. 1a an insert with a barrier layer, Fig. 1b removal of the barrier layer under a protective environment Fig. 1c application of a protective layer to the insert under the protective environment, Fig. 1d an intermediate product consisting of the insert with the protective layer, Fig. 1e a casting tool into which the insert with the protective layer is inserted, Fig. 1f introduction of a casting material in the form of a melt into Fig. 1g the casting tool during a casting process, washing away of the protective layer during the casting process, Fig. 1h dissolving of the protective layer in the melt, Fig. 1i transition of the protective layer into the gaseous state, Fig. 1j a material connection between the surface of the insert freed from the protective layer and the casting material. Detailed description of the characters

[0046] Fig. 1ashows an insert 1 that is to be joined to a cast material. For example, the insert 1 can be an aluminum semi-finished product. Fig. 1a shows an initial state in which an entire surface 1' of the insert 1 is covered with a barrier layer 4 of natural aluminum oxide. This barrier layer 4 is removed in a preparatory step. The removal occurs, for example, via a mechanical-abrasive or a chemical-galvanic or a laser-based or plasma-based cleaning process.

[0047] Fig. 1b shows the process by which the barrier layer 4 of natural aluminum oxide was removed from the surface 1' of the insert 1. This exposes "bare" and oxide-free or low-oxide aluminum at the surface 1'.

[0048] To temporarily avoid new oxidation, the removal process takes place in the absence of atmospheric oxygen, as shown here as an example in a protective environment 6, for example a protective gas atmosphere made of argon or similar, or in a fluidic protective environment.

[0049] Fig. 1cshows that, to permanently prevent new oxidation, a protective layer 3 is applied to the surface 1' of the insert 1 in a protective environment 6. This protective layer 3 preferably does not form a bond to the base material of the insert 1, but is preferably diffusion-tight and thus prevents contact of atmospheric oxygen and other cover layer-forming elements with the surface 1'. Therefore, the application preferably takes place immediately after process step 1 under the same protective environment 6 as the previous process step, in which the barrier layer 4 is removed.The protective layer 3 is formed, for example, from a sol-gel layer, preferably a silicon-containing sol-gel layer, and / or from a plasma polymer layer, preferably a silicon-containing plasma polymer layer, and / or from synthetic resin, and / or from epoxy resin, and / or from a polyelectrolyte multilayer (PEM), and / or from a self-assembling monolayer (SAM), and / or from a polymer layer, preferably containing nitrogen, and / or sulfur, and / or phosphorus, and / or from a metallic layer. The protective layer 3 is formed, for example, in a brewing process, and / or in an electroplating process, and / or by deposition.

[0050] Fig. 1dIllustrates that the protective layer 3, which serves as an oxidation protection layer, remains on the insert 1, so that the insert can be removed from the protective environment 6, for example, the protective gas or protective fluid, for storage and transport and transported in the air. This is therefore an intermediate product for use in a casting process, wherein the intermediate product contains the insert 1 and wherein the protective layer 3 is arranged on a surface 1' of the insert 1 element. This intermediate product can therefore be produced as a supplier part and subsequently fed directly into the casting process.

[0051] Fig. 1e to 1j illustrate the formation of the material connection: The coated (possibly preheated) insert 1 together with the protective layer 3 on its surface 1' is inserted into a casting tool 5 ( Fig. 1e ).

[0052] Fig. 1fIllustrates that the insert 1 is completely or preferably partially cast with a melt 2' (e.g., aluminum melt) in the casting tool 5. For this purpose, a pressure-assisted casting process is preferably provided, in particular a die casting process, but it can also be a low-pressure casting process or a gravity casting process. It is also conceivable for the insert to be cast only in certain areas.

[0053] Fig. 1g to 1iillustrate that the thermal and / or mechanical action of the melt, for example, causes the protective layer 3 to detach from or separate from the surface 1' of the insert 1, thereby exposing the bare, low- or no-barrier-layer aluminum, particularly low- or no-oxide aluminum, again (hence the alternative term "sacrificial layer"). Due to the high speed of mold filling in the die-casting process and, if applicable, an actively created absence of atmospheric oxygen due to a vacuum in the mold, the exposed aluminum surface has no reaction time to form a new barrier layer. The molten aluminum 2' can thus establish direct contact with the aluminum surface 1' and enable the surface of the insert to melt or melt to form a cohesive bond.

[0054] The components of the protective layer 3 are at least partially and preferably completely detached from the insert and transported or washed into the casting or onto its surface ( Fig. 1g ). For example, the protective layer can be flushed into overflows.

[0055] Alternatively or additionally, the protective layer 3 can also be melted and / or dissolved and alloyed with the aluminum melt or remain as a dissolved foreign substance in the aluminum casting ( Fig. 1h ).

[0056] Optionally, the protective layer 3 can alternatively or additionally change into the gaseous state due to the thermal effect of the molten aluminum 2' and be sucked off parallel to the filling of the casting mold 5 ( Fig. 1i ).

[0057] Fig. 1j shows the cast composite component in which the melt has solidified into an aluminum casting material 2 containing the insert 1.

[0058] If necessary, a subsequent heat treatment may be carried out. For example, a subsequent heat treatment of the composite component may be provided to subsequently create, promote, or mature the material bond. This means that it is conceivable that the process for forming the material bond could be carried out during the casting process ( Fig. 1f and 1g or 1h or 1i) does not take place or does not take place sufficiently or is not completed, but is triggered and / or completed in the post-processing step.

[0059] The present disclosure includes, among other things, the following aspects which may be helpful in understanding the invention: 1. A method for producing a material-to-material connection between an insert (1) and a casting material (2), wherein a protective layer (3) is applied to a surface (1') of the insert (1), the insert (1) having the protective layer (3) is brought into contact with the casting material (2) in the form of a melt (2'), the protective layer (3) is removed by contact with the melt (2') so that the surface (1') of the insert (1) is exposed again, and the casting material (2) comes into direct contact with the surface (1') of the insert (1) and forms the material-to-material connection with this surface (1'). 2. A method according to aspect 1, wherein a barrier layer (4) is removed from the surface (1') of the insert (1) before the protective layer (3) is applied. 3. The method according to aspect 2, wherein the barrier layer (4) is removed under a protective environment (6).Method according to aspect 2 or 3, wherein the barrier layer (4) is removed via a mechanically abrasive or a chemical (galvanic) or a laser-based or a plasma-based cleaning process. 5. Method according to one of the preceding aspects, wherein the protective layer (3) is formed from a sol-gel layer, preferably a silicon-containing sol-gel layer, and / or from a plasma polymer layer, preferably a silicon-containing plasma polymer layer, and / or from synthetic resin and / or from epoxy resin and / or from a polyelectrolyte multilayer (PEM) and / or from a self-assembling monolayer (SAM) and / or from a polymer layer, preferably containing nitrogen and / or sulfur and / or phosphorus, and / or from a metallic layer. 6. Method according to one of the preceding aspects, wherein the protective layer (3) is formed in a brewing process and / or is formed in an electroplating process and / or is deposited. 7.Method according to one of the preceding aspects, wherein the insert (1) together with the protective layer (3) located on its surface (1') is preheated and, in a heated state, is brought into contact with the melt (2'). 8. Method according to one of the preceding aspects, wherein the removal of the barrier layer (4) and / or application of the protective layer (3) takes place by means of inline and / or online monitoring, preferably by means of optical, chemical, or electrochemical methods. The monitoring serves to ensure the quality of the surface properties of the insert. 9. Method according to one of the preceding aspects, wherein the melt (2') contains aluminum and / or zinc and / or copper and / or magnesium and / or iron and / or silicon and / or steel and / or nickel and / or titanium. 10.Method according to one of the preceding aspects, wherein the insert (1) is formed from aluminum or magnesium or iron or copper or titanium or zinc or an alloy of these materials. 11. Method according to one of the preceding aspects, wherein the melt (2') is brought into contact with the insert (1) in a pressure-assisted casting process, in particular a die-casting process. 12. Method according to one of the preceding aspects, wherein the melt (2') decomposes and / or evaporates and / or detaches and / or washes away the protective layer (3) and / or the melt (2') alloys with the protective layer (3). 13. Method according to one of the preceding aspects, wherein a subsequent heat treatment is carried out on the insert (1) and the cast material (2) arranged thereon, wherein the material-to-material connection is created and / or promoted and / or matured by the heat treatment. 14.An intermediate product for use in a casting process, wherein the intermediate product is formed from an element provided as an insert (1), wherein a protective layer (3) is arranged on a surface (1') of the element provided as an insert (1). 15. An intermediate product according to aspect 14, wherein the protective layer (3) is formed from a sol-gel layer, preferably a silicon-containing sol-gel layer, and / or from a plasma polymer layer, preferably a silicon-containing plasma polymer layer, and / or from synthetic resin and / or from epoxy resin and / or from a polyelectrolyte multilayer (PEM) and / or from a self-assembling monolayer (SAM) and / or from a polymer layer, preferably containing nitrogen and / or sulfur and / or phosphorus, and / or from a metallic layer. 16. An intermediate product according to aspect 14 or 15, wherein the insert (1) is formed from aluminum. 17.Intermediate product according to one of aspects 14 to 16, wherein the protective layer (3) is in direct contact with a core material of the insert (1).

Claims

1. Method for producing a material-to-material connection between an insert (1) and a casting material (2), wherein a protective layer (3) is applied to a surface (1') of the insert (1), the insert (1) having the protective layer (3) is brought into contact with the casting material (2) in the form of a melt (2'), the protective layer (3) is removed by contact with the melt (2') so that the surface (1') of the insert (1) is exposed again, and the casting material (2) comes into direct contact with the surface (1') of the insert (1) and forms the material-to-material connection with this surface (1').

2. Method according to claim 1, wherein a barrier layer (4) is removed from the surface (1') of the insert (1) before applying the protective layer (3).

3. The method according to claim 2, wherein the barrier layer (4) is removed under a protective environment (6) and / or wherein the barrier layer (4) is removed via a mechanical-abrasive or a chemical (galvanic) or a laser-based or a plasma-based cleaning process.

4. Method according to one of the preceding claims, wherein the protective layer (3) is formed from a sol-gel layer, preferably a silicon-containing sol-gel layer, and / or from a plasma polymer layer, preferably a silicon-containing plasma polymer layer, and / or from synthetic resin and / or from epoxy resin and / or from a polyelectrolyte multilayer (PEM) and / or from a self-organizing monolayer (SAM) and / or from a polymer layer, preferably containing nitrogen and / or sulfur and / or phosphorus, and / or from a metallic layer.

5. Method according to one of the preceding claims, wherein the protective layer (3) is formed in a boiling process and / or is formed and / or deposited in a galvanic process.

6. Method according to one of the preceding claims, wherein the insert (1) together with the protective layer (3) located on its surface (1') is preheated and is brought into contact with the melt (2') in a heated state.

7. Method according to one of the preceding claims, wherein the removal of the barrier layer (4) and / or application of the protective layer (3) is carried out by means of inline and / or online monitoring, preferably by means of optical, chemical or electrochemical methods.

8. Method according to one of the preceding claims, wherein the melt (2') contains aluminum and / or zinc and / or copper and / or magnesium and / or iron and / or silicon and / or steel and / or nickel and / or titanium.

9. Method according to one of the preceding claims, wherein the insert (1) is formed from aluminum or magnesium or iron or copper or titanium or zinc or an alloy of these materials.

10. Method according to one of the preceding claims, wherein the melt (2') is brought into contact with the insert (1) in a pressure-assisted casting process, in particular a die-casting process.

11. Method according to one of the preceding claims, wherein the melt (2') decomposes and / or evaporates and / or detaches and / or washes away the protective layer (3) and / or the melt (2') alloys with the protective layer (3).

12. Method according to one of the preceding claims, wherein a subsequent heat treatment is carried out on the insert (1) and the cast material (2) arranged thereon, wherein the material connection is produced and / or promoted and / or matured by the heat treatment.

13. Intermediate product for use in a casting process, wherein the intermediate product is formed from an element provided as an insert (1), wherein a protective layer (3) is arranged on a surface (1') of the element provided as an insert (1).

14. Intermediate product according to claim 13, wherein the protective layer (3) is formed from a sol-gel layer, preferably a silicon-containing sol-gel layer, and / or from a plasma polymer layer, preferably a silicon-containing plasma polymer layer, and / or from synthetic resin and / or from epoxy resin and / or from a polyelectrolyte multilayer (PEM) and / or from a self-assembling monolayer (SAM) and / or from a polymer layer, preferably containing nitrogen and / or sulfur and / or phosphorus, and / or from a metallic layer; and / or wherein the insert part (1) is formed from aluminum.

15. Intermediate product according to one of claims 13 or 14, wherein the protective layer (3) is in direct contact with a core material of the insert (1).

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