DE102019129128A1 - Engine valve - Google Patents

Abstract

An inlet and outlet regulator valve (2) is disclosed which comprises a valve stem (4), at least one adhesive layer (8) applied in the area of the valve stem (4) and a hard chrome layer (10) applied to the at least one adhesive layer (8). based on chromium (III).

Description

The present invention relates to an engine valve. Engine valves can be inlet or outlet valves that seal the combustion chamber, control the gas exchange in the engine and thus be thermally and mechanically highly stressed components that are also exposed to corrosive influences. The mechanical stress arises as a result of the deflection of the valve disk under ignition pressure and through contact when closing (impact stress).

Such a motor valve is known, for example, from the European patent EP 2 215 334 B1 and from the EP 0 576 190 A1 .

Such engine valves, in particular highly stressed engine valves, are hard chrome-plated or nitrided in the shaft area. The most frequently used galvanic hard chrome plating process is based on chromium (VI). However, this metal may only be used with the approval of the European Chemicals Agency (ECHA), as the chromium (VI) used in the process is a hazardous substance.

Against this background, it is therefore the object of the invention to provide an improved engine valve without the use of hazardous substances during manufacture.

This object is achieved according to the invention by an engine valve according to claim 1.

The inlet and outlet valve according to the invention comprises a valve stem, at least one adhesion promoter layer applied in the area of the valve stem and a hard chrome layer based on chromium (III) applied to the at least one adhesion promoter layer, chromium (III) not being a hazardous substance.

The at least one adhesion promoter layer preferably has nickel, silicon, tungsten and / or cobalt and is preferably applied by sputtering. As a result, the valve stem is subjected to low thermal loads and a high level of adhesive strength is achieved.

The at least one adhesion promoter layer preferably has silicon and / or tungsten, preferably as a gas containing tetrafluorosilane or tungsten hexafluoride, and is preferably by means of plasma-assisted chemical vapor deposition with a layer thickness of 0.5-3 μm, preferably 1-2 μm, particularly preferably 1.25-1 , 75 µm applied. As a result, a high level of protection against corrosion is achieved due to the dense structure.

The at least one adhesion promoter layer preferably has MCrAlY, the material M corresponding to either cobalt or nickel or a combination of both materials and application preferably by high-speed flame spraying or vacuum plasma spraying with a layer thickness of 20-100 μm, preferably 30-70 μm, particularly preferably 40-60 μm. This ensures that the valve stem is resistant to hot corrosion, oxidation and sulphidation.

The at least one adhesion promoter layer preferably has semimetals or, if at least two adhesion promoter layers are present, a metallic layer as one of them, which is preferably produced by physical vapor deposition by magnetron sputtering or high-energy pulse magnetron sputtering with a layer thickness of 0.5-15 μm, preferably 1-10 μm , particularly preferably 1.5-7.5 µm are applied. The higher ionization capacity of the electrons increases the sputtering rate, i.e. significantly higher coating rates with the same process pressure. Since the layer growth and thus the layer properties depend primarily on the process pressure in addition to the temperature, one has a lower process pressure and thus a denser layer with the same growth rates.

The at least one adhesion promoter layer preferably has copper or electrodeposited or elemental nickel, the copper or nickel preferably being electrodeposited using a nickel strike process. This adhesion promoter layer is an ideal starting point for further layers due to the very good adhesive strength, especially for high-alloy steels and stainless steels.

The at least one adhesion promoter layer preferably has electrodeposited semi-precious metals, preferably copper instead of nickel and preferably with a layer thickness of 0.25-4 μm, preferably 0.5-2 μm, particularly preferably 0.75-1.5 μm, whereby increased corrosion protection is obtained .

The at least one adhesion promoter layer is preferably applied by aluminizing for high temperature resistance and corrosion protection.

A modification layer is preferably provided either between the at least one adhesion promoter layer and the hard chrome layer or between the base material of the valve stem and the at least one adhesion promoter layer, which is preferably coated with a nickel strike with a layer thickness of 0.3-1.5 μm, preferably 0.5 μm. 1 μm, particularly preferably 0.5-0.8 μm, is applied. This creates an ideal starting point for further layers due to the very good adhesive strength, especially for high-alloy steels and stainless steels.

The hard chrome layer is preferably electrodeposited with a layer thickness of 0.5-75 μm, preferably 1-50 μm, particularly preferably 5-40 μm, whereby the tribological properties are improved and the valve stem is chemically inert and environmentally compatible.

At least 2 adhesion promoter layers are preferably provided, which are structured differently in order to further improve the adhesive strength.

The at least one adhesion promoter layer, modification layer and / or hard chrome layer are preferably coated with copper and / or electrodeposited or elemental nickel, with the copper or nickel preferably being coated using a nickel strike process with a layer thickness of 0.25-4 μm, preferably 0, 5-2 μm, particularly preferably 0.75-1.5 μm, is electrodeposited. The starting point for further layers is therefore ideal due to the very good adhesive strength, especially for high-alloy steels and stainless steels.

Further advantages and possible applications of the present invention emerge from the following description of the invention in conjunction with the drawing.

1 shows a view of the inlet and outlet control valve according to the invention 2 that has a valve stem 4th having. The coating build-up around the valve stem 4th attached and shown in cross section, has an adhesion promoter layer 8th and a hard chrome layer 10 on.

A first embodiment of the adhesion promoter layer 8th comprises nickel, silicon, tungsten and / or cobalt, preferably applied by sputtering.

A second embodiment of the adhesion promoter layer 8th comprises silicon and / or tungsten, preferably as a tetrafluorosilane or tungsten hexafluoride-containing gas, preferably applied by plasma-assisted chemical vapor deposition with a layer thickness of 0.5-3 μm, preferably 1-2 μm, particularly preferably 1.25-1.75 μm.

A third embodiment of the adhesion promoter layer 8th has one of the alloys [1] cobalt, chromium, aluminum and yttrium, another [2] nickel, chromium, aluminum and yttrium and a third [3] cobalt, nickel, chromium, aluminum and yttrium, preferably by high-speed flame spraying or vacuum plasma spraying a layer thickness of 20-100 µm, preferably 30-70 µm, particularly preferably 40-60 µm.

A fourth embodiment of the adhesion promoter layer 8th contains semimetals or there are at least two adhesion promoter layers 8th present, one of which is a metallic layer, which is preferably applied by physical vapor deposition by magnetron sputtering or high-energy pulse magnetron sputtering with a layer thickness of 0.5-15 μm, preferably 1-10 μm, particularly preferably 1.5-7.5 μm.

A fifth embodiment of the adhesion promoter layer 8th comprises copper or electrodeposited or elemental nickel, the copper or nickel preferably being electrodeposited using a nickel strike process.

A sixth embodiment of the adhesion promoter layer 8th has semiprecious metals, preferably copper instead of nickel and preferably with a layer thickness of 0.25-4 μm, preferably 0.5-2 μm, particularly preferably 0.75-1.5 μm, electrodeposited.

A sixth embodiment of the adhesion promoter layer 8th is produced by aluminizing.

In a further embodiment, there are at least 2 differently structured adhesion promoter layers 8th intended.

The hard chrome layer 10 based on chromium (III) is electrodeposited with a layer thickness of 0.5-75 μm, preferably 1-50 μm, particularly preferably 5-40 μm and has, for example, 100% or 90-100% or 80-100% metallic chromium (III ) on.

2 also shows a modification layer 6th or. 6 ' either between the adhesion promoter layer 8th and the hard chrome layer 10 or between the base material of the valve stem 4th and the at least one adhesion promoter layer 8th is provided. This modification layer 6th or. 6 ' is applied by nickel strike treatment with a layer thickness of 0.3-1.5 µm, preferably 0.5-1 µm, particularly preferably 0.5-0.8 µm.

3 shows another coating 12th or. 12 ' or 12 '' or 12 '''on the adhesion promoter layer 8th , Modification layer 6th and / or hard chrome layer 10 with copper and / or electrodeposited or elemental nickel, preferably the copper or the nickel using a nickel strike process with a layer thickness of 0.25-4 μm, preferably 0.5-2 μm, particularly preferably 0.75-1.5 μm is galvanically deposited.

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

• EP 2215334 B1 [0002]
• EP 0576190 A1 [0002]

Claims (12)

Ein and Auslasstellerventil (2), comprising a valve stem (4), at least one adhesive layer (8) applied in the area of the valve stem (4) and a hard chrome layer (10) based on chrome (III) applied to the at least one adhesion promoter layer (8). Inlet or outlet regulator valve (2) according to Claim 1 , wherein the at least one adhesion promoter layer (8) comprises nickel, silicon, tungsten and / or cobalt and is preferably applied by sputtering. The inlet and outlet valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) has silicon and / or tungsten, preferably as a tetrafluorosilane or tungsten hexafluoride-containing gas, and preferably by means of plasma-assisted chemical vapor deposition with a layer thickness of 0.5 -3 µm, preferably 1-2 µm, particularly preferably 1.25-1.75 µm is applied. Inlet or outlet regulator valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) Cobalt, chromium, aluminum and yttrium, Nickel, chromium, aluminum and yttrium or Cobalt, nickel, chromium, aluminum and yttrium and is preferably applied by high-speed flame spraying or vacuum plasma spraying with a layer thickness of 20-100 µm, preferably 30-70 µm, particularly preferably 40-60 µm. The inlet or outlet regulator valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) has semimetals or at least two adhesion promoter layers (8) are present, one of which is a metallic layer, and preferably by physical vapor deposition by magnetron sputtering or High-energy pulse magnetron sputtering with a layer thickness of 0.5-15 µm, preferably 1-10 µm, particularly preferably 1.5-7.5 µm are applied. The inlet and outlet valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) comprises copper or electrodeposited or elemental nickel, the copper or nickel preferably being electrodeposited using a nickel strike process. The inlet or outlet regulator valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) has semi-precious metals, preferably copper instead of nickel and preferably with a layer thickness of 0.25-4 µm, preferably 0.5-2 µm, particularly preferred 0.75-1.5 µm is galvanically deposited. Inlet or outlet regulator valve (2) according to one of the preceding claims, wherein the at least one adhesion promoter layer (8) is produced by aluminizing. Inlet or outlet regulator valve (2) according to Claim 1 , wherein a modification layer (6) is provided either between the at least one adhesion promoter layer (8) and the hard chrome layer (10) or between the base material of the valve stem (4) and the at least one adhesion promoter layer (8), which is preferably treated with nickel strike a layer thickness of 0.3-1.5 µm, preferably 0.5-1 µm, particularly preferably 0.5-0.8 µm is applied. Inlet or outlet regulator valve (2) according to Claim 1 , the hard chrome layer (10) being electrodeposited with a layer thickness of 0.5-75 μm, preferably 1-50 μm, particularly preferably 5-40 μm. Inlet or outlet regulator valve (2) according to Claim 1 , wherein at least 2 adhesion promoter layers (8) are provided, which are structured differently. The inlet or outlet regulator valve (2) according to any one of the preceding claims, wherein the at least one adhesion promoter layer (8), modification layer (6) and / or hard chrome layer (10) are coated with copper and / or electrodeposited or elemental nickel, preferably the Copper or the nickel is electrodeposited by a nickel strike process with a layer thickness of 0.25-4 μm, preferably 0.5-2 μm, particularly preferably 0.75-1.5 μm.

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