DE102020205537A1 - Wear-resistant coated component and method for coating the same - Google Patents

Abstract

The invention relates to a wear protection coated component (1) made of a steel alloy, in particular a component of a fuel injection system, the tribologically stressed surface of which is at least partially coated by plasma process with a hard outer wear protection layer (2) which is applied to a metallic adhesive layer (3), whereby the metallic adhesive layer (3) is applied to an Fe buffer layer (4) which is applied to the surface of the component (1) in order to separate the surface of the component (1) acting as a diffusion front from the adhesive layer (3).

Description

The invention relates to a wear protection-coated component made of a steel alloy, in particular a component of a fuel injection system, the tribologically stressed surface of which is at least partially coated by a plasma process with a hard outer wear protection layer that is applied to a metallic adhesive layer.

The field of application of the invention extends primarily to motor vehicle technology, in particular to fuel injection systems. Their components, which are usually made of high-alloy steel, such as valve seats of fuel injectors, sliding bearing points in high-pressure pumps and the like, are exposed to strong pressures and frictional loads during operation, so that surfaces of the components of interest here that are subject to high tribological stress are usually provided with a hard wear protection layer, which in particular significantly reduce the coefficient of friction in tribological contacts.

Such wear protection layers contain, for example, chromium nitride, titanium nitride or DLC (diamond-like carbon). In addition to motor vehicle technology, these wear protection layers can also be used in connection with other components, for example in tool technology and to that extent as tool coatings.

State of the art

A well-known method of depositing such wear protection layers on a component surface is the PVD method (PVD = Physical Vapor Deposition), which can work, among other things, on the principle of vacuum arc evaporation. To increase the layer connection, an additional adhesive layer made of a material with good adhesion properties - for example chrome - is usually used as an intermediate layer, which is usually arranged directly on the surface of the steel component, i.e. between it and the hard wear protection layer.

From the DE 10 2009 003 192 A1 a wear protection layer arrangement emerges which is applied in the PVD process, preferably under vacuum, to the surface of a component to be protected. The wear protection layer arrangement has an outer wear protection layer formed from tetrahedral amorphous carbon or having a proportion of tetrahedrally bound amorphous carbon, as well as an adhesive layer between the surface of the component and the wear protection layer. The adhesive layer provided as an intermediate layer consists essentially of titanium and also has at least one oxidation-resistant element. This reduces the high chemical reactivity of titanium and increases the resistance to oxidation in the adhesive layer, which benefits the durability of the entire wear protection arrangement. The adhesive layer is also applied here using the PVD process.

If a component to be coated consists of a high-alloy, hardened, surface-carburized or nitrided steel, additional material phases are formed by diffusion processes at the interface between the steel and the adhesive layer during PVD coating or during component operation, which lead to so-called delamination . The unwanted diffusion process is triggered by a difference in concentration of the individual elements at the interface between the steel material of the component and the adhesive layer. If the adhesive layer material and diffusion material can combine to form a stable phase, an additional intermediate layer is created; for example, titanium from the intermediate layer combines here with carbon from the steel material of the component to form titanium carbide. This additional intermediate layer is therefore not applied in a targeted manner, but is created by the diffusion process of the alloying elements or carbon or nitrogen from hardening processes of the steel material of the component at the interface with the adhesive layer. This results in the problem of crack formation in the additional intermediate layer, which in extreme cases can ultimately lead to the aforementioned delamination.

It is therefore the object of the present invention to further improve a wear protection coated component of the generic type in such a way that a reliable layer adhesion of the outer wear protection layer to the surface even of a high-alloy, hardened or nitrided steel component is achieved with simple technical means.

Disclosure of the invention

The object is achieved on the basis of a wear-resistant coated component according to the preamble of claim 1 in connection with its characterizing features. With regard to a production method for coating the component, reference is made to claim 6. Claim 9 specifies, as a preferred application, a fuel injection system with a component coated with wear protection according to the invention. The dependent claims that refer back in each case are devoted to advantageous developments of the invention.

The invention includes the technical teaching that in the case of a wear protection coated component made of a steel alloy, the tribologically stressed surface of which is coated with a hard outer wear protection layer which is applied to a metallic adhesive layer. This metallic adhesive layer is in turn not applied directly to the component, but on an Fe buffer layer (Fe = iron), which is applied as a further intermediate layer on the surface of the component.

As a result, the surface of the component acting as a diffusion front is separated from the adhesive layer and there is therefore no risk of delamination. This is because the additional iron layer acts as a diffusion buffer and absorbs the alloying elements of the steel material of the component, so that the interface between the iron and the adhesive layer is protected from the formation of additional material phases.

In other words, according to the invention, the metallic adhesive layer is attached to the previously applied Fe buffer layer of the component, so that the concentration gradient of the diffusion of alloying elements from the steel material is present at the transition between the same and the Fe buffer layer, and not to the adhesive layer. The Fe buffer layer is chosen so thick that the diffusion front always remains in the Fe buffer layer over the entire service life of the component. This can be ensured with a layer thickness between preferably 0.01 and 50 μm for the Fe buffer layer, depending on the component material and application.

As a result, there is advantageously no longer a concentration gradient at the interface between the Fe buffer layer and the adhesive layer, so that there is no need to fear delamination.

According to a preferred embodiment for the component material, the high-alloy, hardened or nitrided steel is a material that is selected from a steel group comprising chromium steels, chromium-molybdenum steels, chromium-vanadium steels, chromium-molybdenum steels Vanadium steels. For example, the wear-resistant coated component can consist of nitrided X40CrMoV5-1, which can be used for components of a fuel injector or the like.

In order to ensure a sufficient outer layer hardness, the outer wear protection layer preferably consists of a tetrahedral, hydrogen-free amorphous carbon layer (Ta-C).

• - Bereitstellen eines aus einer Stahllegierung bestehenden Bauteils,
• - Auftragen einer Fe-Pufferschicht auf die Oberfläche des Bauteils, vorzugsweise durch Vakuumbogenverdampfen,
• - Auftragen einer metallischen Haftschicht auf die Fe-Pufferschicht, vorzugsweise durch Vakuumbogenverdampfen,
• - Auftragen einer harten Verschleißschutzschicht auf die metallische Haftschicht, vorzugsweise durch reaktives Vakuumbogenverdampfen.

The wear-resistant coated component described above can preferably be produced by a coating process which comprises the following steps:

• - Provision of a component made of a steel alloy,
• - Application of an Fe buffer layer on the surface of the component, preferably by vacuum arc evaporation,
• - Application of a metallic adhesive layer on the Fe buffer layer, preferably by vacuum arc evaporation,
• - Application of a hard wear protection layer on the metallic adhesive layer, preferably by reactive vacuum arc evaporation.

All the application steps can be carried out in the same coating machine. At least some of the layers are preferably applied using a PVD or CVD process (CVD = Chemical Vapor Deposition), for which pulsed or unpulsed vacuum arc evaporation is particularly suitable.

The metallic adhesive layer preferably consists of high-purity chromium, titanium, tungsten and / or molybdenum. A mixture of titanium-aluminum or the like is also conceivable. The adhesive layer increases the resistance of the hard wear protection layer and can also be applied automatically by plasma coating in a vacuum coating machine, which for this purpose deposits the adhesive layer element. The adhesive layer can also be applied in multiple layers.

Figure list

• 1 einen schematischen Längsschnitt durch ein verschleißschutzbeschichtetes Bauteil gemäß der Erdfindung, und
• 2 einen Ablaufplan der Verfahrensschritte zum Beschichten des Bauteils nach 1.

Further measures improving the invention are shown in more detail below together with the description of a preferred exemplary embodiment of the invention with reference to the figures. It shows:

• 1 a schematic longitudinal section through a wear-resistant coated component according to the earth finding, and
• 2 a flow chart of the process steps for coating the component according to 1 .

According to 1 there is a component - shown here only schematically 1 made of hardened, high-alloy chrome-molybdenum steel. The hardening process results in carbon in the material structure. The component 1 is with a hard outer wear protection layer 2 provided, which is known as a well-known tetrahedral hydrogen-free amorphous carbon layer is formed and to that extent a protection for the tribologically stressed surface of the component 1 forms.

The hard outer wear protection layer 2 is on a metallic adhesive layer 3 Applied from high-purity chrome. This metallic adhesive layer 3 is in turn on an Fe buffer layer 4th applied on the surface of the component 1 is applied. Through the Fe buffer layer 4th becomes the surface of the component acting as a diffusion front 1 from the adhesive layer 3 separated to prevent delamination. Specifically, the carbon can come from the steel alloy of the component 1 not with the chrome from the adhesive layer 3 combine to form chromium carbide, which results in an additional material phase which would lead to delamination as a result of cracking. Instead, the diffusion process takes place entirely in the Fe buffer layer 4th instead, so that alloying elements of the component 1 not up to the adhesive layer 3 can advance.

According to 2 a component is coated 1 with the wear protection resistant according to the invention, in that in a step A first a component made of a steel alloy 1 provided. Then, in a step B, an Fe buffer layer is applied 4th by plasma process on the surface of the component 1 deposited. In a step C, a metallic adhesive layer is then applied 3 on the Fe buffer layer 4th applied by plasma process. Finally, in a step D, the outer hard wear protection layer is applied 2 onto the metallic adhesive layer 3 applied by plasma process.

Applying the Fe buffer layer 4th , the metallic adhesive layer 3 as well as the hard wear protection layer 2 takes place in this embodiment by deposition using the PVD process as a plasma process, specifically by vacuum arc evaporation, in the same PVD machine after the component 1 has been provided in a cleaned state.

The invention is not limited to the preferred exemplary embodiment described above. Rather, modifications thereof are also conceivable, which are also covered by the scope of protection of the following claims. For example, instead of a vacuum arc evaporator, it is also possible to use a different plasma coating method for applying the layer structure to the surface of the component. This can also consist of another high-alloy steel of the steel groups specified above, which is hardened, carburized or nitrided in order to achieve a high component strength for a tribological load which preferably occurs in the context of a fuel injection system.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102009003192 A1 [0005]

Claims (9)

Wear protection-coated component (1) made of a steel alloy, in particular a component of a fuel injection system, the tribologically stressed surface of which is at least partially coated by plasma process with a hard outer wear protection layer (2) which is applied to a metallic adhesive layer (3), characterized in that the metallic adhesive layer (3) is applied to an Fe buffer layer (4) which is applied to the surface of the component (1) in order to separate the surface of the component (1) acting as a diffusion front from the adhesive layer (3). Component (1) after Claim 1 , characterized in that the Fe buffer layer (4) is applied with a layer thickness between 0.01 and 50 micrometers. Component (1) after Claim 1 , characterized in that the metallic adhesive layer (3) consists of high-purity chromium, titanium, molybdenum and / or tungsten. Component (1) after Claim 1 , characterized in that the component (1) is designed as an alloyed, high-alloy, hardened, carburized or nitrided steel, selected from a steel group comprising: chrome steels, chrome-molybdenum steels, chrome-vanadium steels, chrome-molybdenum -Vanadium steels. Component (1) after Claim 1 , characterized in that the outer wear protection layer (2) is designed as a tetrahedral, hydrogen-free amorphous carbon layer (ta-C) or as a layer of chromium nitride, titanium nitride or aluminum titanium nitride. Method for coating a component (1) according to one of the preceding claims, comprising the following steps: - Providing (A) a component (1) consisting of a steel alloy, - Application (B) of an Fe buffer layer (4) on the surface of the component (1), - Application (C) of a metallic adhesive layer (3) on the Fe buffer layer (4), - Application (D) of a hard wear protection layer (2) on the metallic adhesive layer (3). Procedure according to Claim 6 , characterized in that the Fe buffer layer (4), the metallic adhesive layer (3) and / or the hard wear protection layer (2) are applied using a PVD or CVD process. Procedure according to Claim 7 , characterized in that the application is carried out by vacuum arc evaporation. Fuel injection system of a motor vehicle with at least one tribologically loaded, wear-resistant coated component (1) according to one of the Claims 1 until 5 .

Images