DE102013112079A1 - Material composition for the thermal coating of surfaces and associated method - Google Patents

Abstract

The present invention is a material composition for the thermal coating of surfaces of components in the course of the realization of wear and / or corrosion protection layers. The material composition consists essentially of a matrix component and a hard material component, the matrix component defining a matrix for the hard phase included therein. According to the invention, the matrix component is based on copper as the base material.

Description

The invention relates to a material composition for the thermal coating of surfaces on components in the course of the realization of wear and / or corrosion protection layers, consisting essentially of a matrix component and a hard material component, wherein the matrix component defines on the relevant surface a matrix for the hard phase enclosed therein. - D. h., The matrix component and the hard material component taken together - except for any impurities - finally the material composition.

In the context of the invention is a material composition that can be applied in principle of any shape on the surface to be coated on components. The components are typically metallic components. The material composition may include a flux cored wire or a filler tape as a constituent, as in the generic art DE 102 59 141 A1 is described. This is about a material system, which is used in the course of thermal coating for surface coating. Thermal coating methods are usually procedures such as thermal spraying, plasma deposition welding or arc welding.

All of the procedures described for the thermal coating of surfaces on, in particular, metallic components are used and implemented in order to provide increased mechanical strength for improving the surface properties of the component. For this purpose, the material composition is used to be able to define a corresponding wear and / or corrosion protection layer with their help on the surface to be protected of the component.

The two components have a different function. The matrix component forms on the surface to be coated a layer or matrix into which the hard material component is enclosed as hard phase. The hard material component is typically grains of particular hardness, for example those of tungsten-melting carbide. These hard grains mainly provide the desired strength and thus armor of the surface.

In the prior art according to the DE 102 59 141 A1 A cored wire or filling belt made of a metallic sheath made of nickel, a nickel alloy, iron or iron alloy is used. In addition, a filling of embedded vanadium carbides is provided, which are provided as coarse carbides and / or Feinstkornagglomerate with 10 to 35 wt .-%. As a result, a nickel-based matrix incorporating the vanadium carbides is observed. In the case of the thermal application of such a material composition, there is basically the risk that the hard material particles will be wholly or partly dissolved by the matrix material or the matrix component. This results in any hardness losses of the stored carbides. These emerge in particular in the edge region of the embedded hard material particles. As a consequence, there is a risk that, in particular in a striking stress of the surface thus equipped or the component, the wear and / or corrosion protection layer flakes off completely or partially, so that the protection no longer exists and a reprocessing is required.

Although one has in the further state of the art after the DE 10 2007 019 150 A1 describes a material system in which the matrix component based on their total weight, a proportion of at least about 10%, in particular at least about 20% of another metal in addition to nickel as the main constituent of the group copper or iron. By this metal mixture in the realization of the matrix component, a good wear protection effect to be achieved and at the same time a cost-effective material can be made available. However, the matrix still has nickel as its main constituent.

As part of the DE 101 63 976 A1 A method for producing a wear protection layer by means of an arc spraying method is described. In this case, the metal matrix of the surface coating is an iron or nickel-based material. In addition, the base material contains fractions of chromium, boron, silicon, chromium carbide, titanium carbide, tungsten carbide, molybdenum carbide and carbon. This is intended to provide a method for producing a wear-resistant surface coating which can be used without the use of explosive gases.

The prior art may not be satisfactory in all aspects. In particular, there is the already indicated danger that the hard material particles embedded in the matrix or enclosed by the matrix are melted on their surface during the thermal coating, at least slightly. As a result, their hardness drops in this area and there is a risk, especially when a striking action is taken on the appropriately equipped surface, that the hard particles in question, either alone or together with the matrix that normally holds them, flake off the surface and actually protect them Surface is exposed. Such striking stresses are observed, for example, when a drill head for oil and gas exploration abruptly hits a boulder. Similar burdens also arise, for example, bucket wheel excavators for lignite mining, when rocks or rock formations are hit in the earth actually to be removed. Here, the invention aims to provide a total remedy.

The invention is based on the technical problem of further developing such a material composition so that the wear and / or corrosion protection layer permanently adheres to the surface of the component to be coated and, in particular, controlling stresses are controlled.

To solve this technical problem, a generic material composition in the context of the invention is characterized in that the matrix component comprises copper as the base material.

In the context of the invention, therefore, a special matrix component is used for realizing the matrix receiving the hard material grains, namely one which uses copper as the base material. That is, of the materials for realizing the matrix component, and hence the matrix, copper is by weight, based on the matrix component, the major constituent.

In this context, the matrix component advantageously comprises copper as the main constituent with more than 30% by weight and in particular more than 50% by weight, in each case based on the weight of the matrix component. As a consequence thereof, the component equipped on the surface with the material composition according to the invention has a matrix of a copper base material. Such a matrix of the copper base material or using a matrix component with copper as main component is basically characterized by a lower (Vickers) hardness compared to a nickel matrix, as for example in the prior art according to the DE 102 59 141 A1 is observed.

In fact, the hardness of the matrix component according to the invention with copper as the base material is in the range of about 100 HV, in any case regularly below 500 HV and is in particular less than 300 HV, whereas for nickel-based matrices Vickers hardness of typically more than 500 HV and even up to 600 HV and more are observed (cf. DE 103 01 135 B4 Section [0004]).

In any case, the matrix realized according to the invention, taking recourse to the special matrix component with copper as the base material, is markedly "softer" than, for example, a nickel-chromium-based matrix used in the prior art, whereby a halving of the Vickers hardness is observed at this point. Nevertheless, the wear and / or corrosion protection layer defined with the aid of the material composition according to the invention as a whole is equipped with comparable degrees of hardness as in the prior art. This can essentially be attributed to the fact that the hard phase embedded in the matrix or the hard material particles held by the matrix typically have a Vickers hardness of more than 2000 HV. Since the wear protection is made available almost exclusively by these particles, at least comparable service lives and lifetimes of the realized protective layer are observed in comparison with the prior art.

In fact, the wear and / or corrosion protection layer realized with the aid of the material composition according to the invention is even equipped with the particular advantage that a striking application of the surface does not or does not necessarily lead to the spalling of the wear and / or corrosion protection layer. This can essentially be attributed to two phenomena that are essential to the invention.

First of all, the melting point of the matrix component according to the invention with copper as the base material is typically below 1200 ° C., in most cases even below 1100 ° C. This applies a fortiori when the matrix component has, in addition to copper as its main constituent, other constituents such as, for example, aluminum or silicon as additional constituents. Even if nickel or magnesium are used as additional constituents, melting points of the matrix component are observed in this range.

In contrast, predominantly nickel-based or nickel-chromium-based matrix components require thermal coating temperatures that exceed 1500 ° C. and more to allow the matrix component to melt and cover the surface of the component to be coated. Such temperatures in the case of nickel-based matrices come within the range of the melting points of the hard materials used, which as a rule are more than 2000.degree. C., for example for tungsten carbide at about 2500.degree. This leads in the prior art to the fact that the hard particles embedded in the matrix can (slightly) melt or melt at least on their surface, so that their adhesion or their hold in the nickel-chromium-based matrix is weakened. Such a weakening is noticeable in particular in the case of a striking stress of the thus realized wear and / or corrosion protection layer.

In contrast, in the context of the invention due to the large distance of the melting points of one part of the matrix component and on the other hand, the hard material component of usually at least 800 ° C and usually even more than 1000 ° C to be expected that the stored in the realized matrix hard particles, also not superficially melted, maintain their hardness and in particular are firmly anchored in the matrix. In connection with the further fact that, in the context of the invention, the matrix based on the matrix component with copper as the base material is altogether softer than that based on, for example, nickel, it is possible to control blows or generally impacting stresses particularly well. For the proper anchoring of the hard material particles in the copper-based matrix on the one hand and the increased elasticity of the copper-based matrix on the other hand according to the invention to the fact that in particular beating stresses on the surface as it were cushioned and do not cause the wear protection layer flakes off. As a consequence of this, particularly long service lives of the thus realized wear and / or corrosion protection layer can be observed.

As a rule, the matrix component and the hard material component are present in a weight ratio of 70 to 30 to 30 to 70, based on the total material composition. That is, the matrix component can account for up to 70% by weight of the total material composition. In this case, a proportion of 30 wt .-% of the total material composition is observed for the hard material component. In principle, however, the ratio can also be reversed. In this case, the proportion by weight of the matrix component of the total material composition is 30 wt .-%, whereas the hard material component occupies a weight fraction of 70 wt .-%. Between these two pairs of values, any conceivable mixture compositions are included within the scope of the invention.

As already explained in the introduction, the matrix component in addition to copper as a main component and aluminum, nickel, manganese, molybdenum, silicon, chromium, etc. as additional components. In any case, it is ensured that copper is still the main constituent of the matrix component, ie the weight-average constituent of the matrix component which is the largest.

The matrix component and the hard material component may be in granular or powder form. In this case, grain sizes of less than 100 microns have generally proven to be favorable. As a result, the material composition according to the invention can be applied, for example by thermal spraying or plasma spraying, to the surface to be suitably equipped.

Alternatively or additionally, however, the matrix component can also be largely realized in wire form with or without filling. In the former case, the invention uses, for example, a cored wire which consists mainly of copper. The filler wire in question in this case has a filling of predominantly the hard material component. For example, the filler wire, based on the material composition, a component of 60 wt .-%, wherein the filling occupies 40 wt .-% of the total material composition. The 40% by weight filling in turn may be composed of 80% by weight of the hard material particles and, for example, 20% by weight of aluminum powder, based on the filling.

As a consequence thereof, in the example case, a proportion of about 60% by weight of copper, about 30% by weight of hard material component or hard material (0.4 × 80% by weight) and about 10% by weight of aluminum is observed (0.4 × 20% by weight), which must be added to the matrix component or the 60% by weight of copper, in each case based on the material composition. That is, in this case, the material composition according to the invention consists of 70 wt .-% of the matrix component (60 wt .-% filler wire of copper and about 10 wt .-% aluminum powder as part of the filling) and 30 wt .-% of the hard material component together.

Alternatively or additionally, however, it is also possible and within the scope of the invention that the matrix component is provided in wire form and the hard material component is supplied, for example, as granules in a corresponding welding process, for example an arc welding process. Mixed forms are also conceivable.

The hard material component is advantageously tungsten carbide, boron nitride or a similar non-metallic hard material, which typically has a Vickers hardness of more than 2000 HV. In contrast, the Vickers hardness of the matrix is - as already explained - regularly in the range of 100 HV and generally below 500 HV located. The invention also provides a process for the thermal coating of surfaces, as explained in more detail in claim 10.

The production of the material composition according to the invention for the thermal coating of surfaces will be explained in more detail below with reference to a drawing representing only one exemplary embodiment. This shows the only figure in the 1A the production of a cored wire schematically, whereas in the 1B to 1E respectively sectional views of the filler wire are reproduced in individual stages of manufacture.

One recognizes in the figures first of all a copper winding 1 , one of which is in the 1B in section shown strip-shaped copper band 2 is handled. The copper band 2 has in principle an infinite length and has a width of for example 20 microns. Depending on the desired length of the filler wire to be produced, the copper strip 2 suspended in the process. The copper band 2 is in a first rolling mill 3 at its longitudinal edges trough-shaped bent so that each upstanding edges 4 at the longitudinal edges of the copper band 2 be generated, like the 1C makes it clear.

The two longitudinal edges 4 are then in a further rolling mill 5 so far bent that in the 1D illustrated trough-like expression of the copper strip 2 is produced. In this tub can then in a subsequent filling station 6 a filling 7 be introduced. At this filling 7 it may be 80% by weight of hard material particles and 20% by weight of aluminum powder, based on the total weight of the filling. As a result, the trough-shaped and elongated copper strip 2 with the filling 7 equipped in the sectional view after the 1D is hinted at.

Finally, the trough-shaped copper strip happens 2 another roll stand 8th , which spirally engages a longitudinal edge under cover with the other longitudinal edge of this and in total in the 1E in section shown closed flux-cored wire with the filling 7 manufactures. Previously like the copper band 2 have been suspended.

Based on the material composition according to the invention, the matrix component realized in this way initially comprises 60% by weight of copper in the form of the shaped copper strip 2 on. The remaining 40 wt .-% of the material composition are from the filling 7 provided, which in turn is composed of the hard material particles and the aluminum powder. In this case, the filling may for example consist of 80% by weight of hard material particles and 20% by weight of aluminum powder, as has already been explained in detail above.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10259141 A1 [0002, 0005, 0012]
• DE 102007019150 A1 [0006]
• DE 10163976 A1 [0007]
• DE 10301135 B4 [0013]

Claims (10)

Material composition for the thermal coating of surfaces on components in the course of the realization of wear and / or corrosion protection layers, consisting essentially of a matrix component and a hard material component, wherein the matrix component on the respective surface defines a matrix for the hard phase enclosed therein, characterized in that the matrix component comprises copper as the base material. Material composition according to claim 1, characterized in that the matrix component copper as the main component with more than 30 wt .-%, in particular more than 50 wt .-%, based on the matrix component having. Material composition according to claim 1 or 2, characterized in that the matrix component and the hard material component in the weight ratio 70 to 30 to 30 to 70 in the material composition. Material composition according to one of claims 1 to 3, characterized in that the matrix component in addition to copper as the main constituent of aluminum, nickel, magnesium, molybdenum, chromium, silicon, etc. as additional constituents. Material composition according to one of claims 1 to 4, characterized in that the matrix component and the hard material component are present in granular and / or powder form. Material composition according to one of claims 1 to 5, characterized in that the matrix component is largely realized in wire form with or without filling. Material composition according to claim 6, characterized in that the matrix component is formed as a filler wire of mostly copper with a filling of predominantly the hard material component. Material composition according to one of claims 1 to 7, characterized in that the hard material component consists of tungsten carbide, boron nitride or comparable non-metallic hard materials. Material composition according to one of claims 1 to 8, characterized in that the Vickers hardness of the matrix in the range of 100 HV, below 500 HV and that of the hard phase at more than 2000 HV is located. Process for the thermal coating of surfaces on components for the realization of wear and / or corrosion protection layers, according to which a material composition consisting essentially of a matrix component and a hard material component is applied to the surface to produce a matrix with hard phase enclosed therein, characterized in that the matrix made of copper as a base material.

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