EP3325685A1

EP3325685A1 - Method for coating a cylinder barrel of a cylinder crankcase, cylinder crankcase with a coated cylinder barrel and engine

Info

Publication number: EP3325685A1
Application number: EP16730300.7A
Authority: EP
Inventors: Klaus Stefan Klimek; Stefan Richter; Jürg WIPF
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2015-07-23
Filing date: 2016-06-08
Publication date: 2018-05-30
Anticipated expiration: 2036-06-08
Also published as: CN107810290B; EP3325685B1; WO2017012769A1; CN107810290A; DE102015213896A1

Abstract

The invention relates to a method for coating a cylinder barrel of a cylinder crankcase. It is provided that the method comprises the steps a: providing a powdered basic material and a powdered bonding agent, wherein the bonding agent comprises a mixture of molybdenum (Mo) and an aluminium-containing alloy (A(X)Al), and b: applying the basic material and the bonding agent to a cylinder barrel (1) of a cylinder crankcase (10) by means of a thermal coating process, either - by applying a layer (3) of a powder mixture of bonding agent and basic material, or - applying a first layer (5), comprising the bonding agent, to the surface of the workpiece and subsequently applying a second layer (6), comprising the basic material, to the first layer (5). The invention also relates to a cylinder crankcase (10) with a cylinder barrel (1) that has a coating (2), it being provided that the coating (2) has - a layer (3, 5), comprising a basic material and/or a bonding agent of molybdenum (Mo) and an aluminium-containing alloy (A(X)Al), arranged on a surface of the workpiece (1) and - if the first layer comprises both the basic material and the bonding agent, a further layer (6), which comprises the basic material but not the bonding agent, arranged on the layer (5).

Description

description

Method for coating a cylinder bore of a cylinder crankcase,

Cylinder crankcase with a coated cylinder bore and engine

The invention relates to a method for coating a cylinder bore of a

Cylinder crankcase, a cylinder crankcase and a motor.

For coating workpieces nowadays thermal spraying processes are frequently used, such as plasma spraying; High velocity flame spraying (HVOF), arc spraying and arc wire spraying. With these methods, layers are produced on a workpiece, wherein the workpiece is metallic, for example, and the

Coating metallic, ceramic or may be a mixture of both. Often, the coating comprises several individual layers, which are arranged one above the other and usually have different functionalities. Thus, e.g. Thermal protection layers (TBC) known, corrosion protection layers, erosion protection layers or sliding layers, which facilitate the sliding of mating bodies together. An application example here is the coating of cylinder surfaces in internal combustion engines with layers having good lubricating and friction properties, whereby the running characteristics of the piston in the cylinder are improved.

In vehicle construction and in particular in the production of cylinder crankcases (ZKG), lightweight construction is becoming more and more important. For this purpose, aluminum cylinder crankcases are used, which have a coating in the cylinder bore. The effect of the coating is in addition to a robustness increase the career significantly reduced friction in the area of the piston group and associated with a reduction in C0 ₂ emissions, as well as positive effects against corrosive media. Common thermal

Coating processes include powder plasma spraying, wire spraying processes such as plasma transfer wire arc (PTWA) and arc wire spraying (LDS) or

High velocity flame spraying.

Prior to a thermal coating of cylinder bores in crankcases made of aluminum and gray cast iron, a roughening process is required to bond the coating in the surface. The roughening process is carried out by radiative processes using corundum or water (medium pressure / high pressure water jets), laser beam roughening or roughening with a geometrically defined cutting edge. However, the methods described have the disadvantage that the blasting medium must be elaborately processed, and also the processes must be monitored by additional and extensive analysis methods and large quantities of dusts, shavings and sludge must be removed and disposed of. Furthermore, high investments must be made to install these Aufrauprozesse.

Furthermore disadvantageous is the emulsion rinse of the blades used during mechanical roughening, which is often not effective enough, so that chips always remain in the roughening profile and adversely affect the layer structure and the layer quality in the coating process. The same applies to the water or Laserstrahlaufrauverfahren produced

Surfaces that show strong pits and bead / spatter like elevations. In addition, high investments must be made to install these Aufrauprozesse.

The invention is based on the object of providing a method for coating a metallic workpiece, in particular a cylinder bore of a cylinder crankcase, in which a pretreatment and in particular roughening of the surface are dispensable.

This task is performed using a procedure with the characteristics of the first independent

Claim solved.

Thus, a first aspect of the invention relates to a method for coating a

Cylinder track of a cylinder crankcase comprising in step (a) providing a powdery base material and a powdery adhesion promoter, wherein the adhesion promoter comprises a mixture of molybdenum and an aluminum-containing alloy, such as NiAl, in particular Ni (95%) Al (5%), or CuAl, in particular Cu (90%) Al (10%). Particularly preferred is the use of Ni (95%) Al (5%) as an aluminum-containing alloy for the adhesion promoter. Furthermore, the method according to the invention comprises

Applying the base material and the bonding agent on the cylinder bore of the

Cylinder crankcase by means of a thermal coating process in a step (b), wherein either a layer of a powder mixture of adhesion promoter and

Base material is arranged on the cylinder liner or a first layer comprising the bonding agent arranged on the cylinder barrel and then a second layer comprising the base material is disposed on the first layer. Thermal coating processes include powder plasma spraying, wire spraying processes such as plasma transfer wire arc (PTWA) and arc wire spraying (LDS) or

High velocity flame spraying.

Surprisingly, it has been found that a mixture of molybdenum and an aluminum-containing alloy for coatings for reducing wear acts as a bonding agent such that no pretreatment of the cylinder bore is necessary. Also, the surface quality for the coating according to the invention is irrelevant and thus no minimum surface roughness is required. Therefore, the processing of coated cylinder crankcases can be greatly simplified by the inventive method.

The adhesion promoters mentioned partly, as in the case of NiAl, by exothermic reaction of the components with one another, in particular in conjunction with molybdenum to a very good adhesion, in particular Ni (95%) Al (5%) has been found to be suitable.

During coating, however, according to no embodiment of the invention, self-growth or self-welding of the layer with the cylinder crankcase takes place, therefore no intermetallic bonds are produced.

In particular, a process step for pretreatment, which precedes a coating of the workpiece, is not necessary and can be saved. This saving leads to economic, especially financial advantages, since the process time is reduced overall. If the pretreatment is a roughening of the material, there is no need for expensive disposal of the materials used during the roughening process. When using the method according to the invention an increase in quality of the workpiece is achieved in addition, since errors on the workpiece surface, which can be caused by the pretreatment, in particular the roughening of the surface, be completely avoided. Thus, with the method according to the invention also finely spindled surfaces can be coated without sacrificing quality.

The coating produced by the method according to the invention serves as a protective layer for a cylinder bore of a cylinder crankcase. Preferably, by the

Protective layer increases the friction resistance. The properties of the protective layer are largely determined by the base material. According to the invention, the adhesion promoter is either arranged together with the base material on the metallic workpiece surface (cylinder bore) and is then present together with the base material in a mixed layer on the workpiece surface, so that an adhesive base formed in the protective layer is formed. Alternatively or in addition, this looks

inventive method before, the bonding agent in a separate layer without

Base material to be arranged as a primer on the workpiece surface and then to be placed on the primer a protective layer, which preferably only the base material, but at least not the adhesion promoter has.

The bonding agent and the base powder lie as a physical mixture, so do not form any chemical compounds or alloys.

The separation of primer and base material in two layers offers several advantages. On the one hand, the effect of the adhesion promoter can be increased and thus the adhesion of the coating on the workpiece surface can be improved, on the other hand, the adhesion promoter does not come with a separate application of the individual layers with the

Environment of the workpiece in contact. An interaction of the bonding agent with the environment of the workpiece can thus be avoided.

Preferably, the coating of all said layers takes place with the same thermal coating process. Thus, the disadvantages of an additional

Coating step negligible, especially if special precautions are taken, such as the use of a plasma torch with

Double powder conveyor for powder delivery, to minimize the overhead of an additional coating step. So can in the provision of

For example, a barrel primer and a barrel base material a change between the two powders can be done easily, advantageously a cleaning or a change of a feed tube or similar. is not required.

It has been found that the method according to the invention is used with particular advantage in workpieces which have a light metal surface, in particular an aluminum-containing one

Alloy such as AISi ₁₇ , AISi ₉ , and others, or more particularly one

Gray cast surface, with a gray cast iron surface is particularly preferred since corresponding cylinder linings prove to be particularly durable. The aluminum-containing alloy of the coupling agent is preferably a nickel-aluminum alloy (nickel-base alloys), a copper-aluminum alloy optionally containing iron, a cobalt-aluminum alloy, a silicon-aluminum alloy, a magnesium-cobalt-aluminum alloy, a silver-aluminum alloy , Cobalt-chromium-based hard alloys or aluminum bronze.

Particularly good results, in particular good adhesion of the coating of the

Base material is achieved when molybdenum in the range of 20 to 80 wt .-% and / or the aluminum-containing alloy in the range of 20 to 80 wt .-% based on the adhesion promoter is present. These details are preferably based on the provided powdery material. Preferably, the adhesion promoter in addition to molybdenum and aluminum of the aluminum-containing alloy has no further components, so that the percentage of

Molybdenum and the aluminum-containing alloy preferably add to 100%. Alternatively, the adhesion promoter has 0-60% of the base material to be coated on the adhesion promoter, which then adds up to 100% with molybdenum and the aluminum-containing alloy. It is further preferred that 0.2-5% of boron be added to the coupling agent to aid adhesion.

Also good results are achieved with a silicon-aluminum alloy, preferably the silicon content is from 8 to 25 wt .-% based on the adhesion promoter.

Another way to achieve good adhesive properties is the use of hard alloys preferably cobalt-chromium-based, wherein the alloy preferably from 26 to 29 wt .-% chromium, 4.5 to 6 wt .-% molybdenum, 0.2 to 0.35 wt .-% carbon, 2 to 3 wt .-% nickel and up to 67 wt .-% cobalt and other components in a small extent, for example, iron, silicon and / or manganese.

The inventive method can be carried out with all known coatings which are suitable for wear of the workpiece surface by temperature and / or

Reduce friction stress. With particular advantage, the base material comprises iron or an iron alloy, steel, preferably a low-alloy steel or an iron-based steel, in particular 100Cr6, with 0.05 to 1.5 wt .-% carbon; 0.05 to 3.5% by weight of manganese; 0.05 to 3.0% by weight of chromium; 0.01 to 1% by weight of silicon and / or 0.001 to 0.4% by weight of sulfur and / or a chromium steel having an iron base and 0.05 to 0.8% by weight of carbon; 0-3% by weight of molybdenum; 0.05 to 1 .8% by weight of manganese; 1: 1 to 5 wt% chromium; 0.01 to 1% by weight of silicon and / or 0.002 to 0.2% by weight of sulfur). Also the use of titanium dioxide is preferred. These are particularly well suited as a protective layer, in particular for cylinder components, and interact with the adhesion promoters mentioned in such a way that adhesion, in particular to cast iron but also to light metal surfaces, is markedly improved.

In a preferred embodiment of the invention it is provided that the adhesion promoter and the base material by weight in a ratio of about 10: 90, 20: 80, 30: 70, 40: 60 or 50: 50 in the powder mixture of primer and base material available.

This ensures that the desirable properties of the base material, in particular the improvement of the wear properties of the workpiece surface are not impaired by the presence of the adhesion promoter. Particularly good properties of a protective layer in which the base material and the adhesion promoter are mixed are achieved when the adhesion promoter is 20 (± 5)% and the base material is 80 (± 5)% in the

Powder mixture present. A coating applied with the method according to the invention in this embodiment shows an optimum ratio of friction resistance and adhesion.

In a further preferred embodiment of the method, the method comprises a further step (c), in which the base material by means of the thermal

Coating method is applied to the coating produced in step (b). This embodiment is particularly advantageous if in step (b) a powder mixture of base material and adhesion promoter is applied to the workpiece surface. In this preferred embodiment, it is ensured that the coated workpiece surface with a layer comprising the base material, but not the adhesion promoter, against the

Environment completes. Thus, interactions between the materials of the primer and the environment, such as a mobile phase; be excluded. Furthermore, the properties of the base material on the surface of the

Unrestricted use of the workpiece.

In a particularly preferred embodiment of the method, it is provided that the thermal coating method is plasma spraying. When plasma spraying are

usually in a plasma torch an anode and up to three cathodes separated by a narrow gap. A DC voltage creates an arc between the anode and the cathode. The flowing through the plasma torch gas or gas mixture is passed through the arc and thereby ionized. The dissociation, or subsequent Ionization, generates a highly heated (up to 30,000 K), electrically conductive gas of positive ions and electrons. In this Plasmajet produced powder (usual particle size distribution: 5- 200 μηη, in certain devices is also a grain size of down to 100 nm possible) injected, which is melted by the high plasma temperature. The plasma stream entrains the powder particles and throws them onto the workpiece to be coated. The

Gas molecules return to a stable state after only a short time, and so the plasma temperature drops again after a short distance. The

Plasma spray coating is carried out in normal atmosphere, inert atmosphere (under inert gas such as argon), in vacuum or under water, the coating under normal (compressed air) atmosphere is preferred because this process costs are lower compared to the other variants. For layer quality, the speed, temperature and composition of the plasma gas are important. Gases used may be argon, nitrogen, hydrogen or helium.

The plasma spraying generates optimally constructed layers for cylinder liners with a non-communicating microporosity, which after the manufacturing process as

Oil retention volume on the smooth honed cylinder surface is used. On a conventional Honriefenstruktur as oil retention volume can be omitted. Plasma spraying is widely used industrially because of its universal applicability and has high advantages due to its advantages such as flexible material selection (process allows a wide range of sprayable materials which are easy to prepare and mix)

Particle impact velocities, good adhesion of the applied layers and, due to the compact burner design, the ability to perform an internal coating even at small diameters, obtained the greatest importance under all thermal spray processes.

High-speed flame spraying is also established on the market, but is unsuitable for cylinder liner coating, since very dense layers are applied here, which have little porosity and often lead to failure during engine operation. Furthermore, burners for interior coatings are not yet realized.

Wire spraying methods are an alternative for cylinder liner coatings, but here layers are produced which have a significantly lower porosity compared to the plasma spraying layers and thus have only a few large pores on the raceway surface after honing, which in most cases are insufficient as oil retention volumes. Another disadvantage is the strong oxide formation, especially in the single-wire method (PTWA or RSW), if the layers are injected without protective gas and so can lead to increased susceptibility to corrosion. This oxide formation does not lead to a continuous oxide layer.

With particular advantage, the method comprises no pretreatment of the surface of the workpiece, in particular no roughening of the surface of the workpiece. The

The inventive method does not exclude the possibility of pretreatment, but the inventive method allows the pretreatment of

Workpiece surface, in particular by roughening the workpiece surface, can be omitted. Failure to pre-treat the surface of the workpiece, particularly omitting the roughening of the surface leads, in addition to a high process cost savings, to an improvement in the quality of the coated surface. Furthermore, finely spindled surfaces can also be coated with the method according to the invention if a pretreatment, in particular a roughening, by means of which the finely spindled

Surface changed, in particular destroyed, would become, omitted.

The method according to the invention has various steps which can be selected from the list below, wherein the above-mentioned steps essential to the invention are mandatory:

Casting a cylinder crankcase.

Cylindrically cut the conical casting geometry of the cylinder bore resulting from casting.

Fine spindles of the surface of the cylinder liner.

Washing and vacuum drying the cylinder crankcase at room temperature, (a) providing a powdery base material and a powdery one

bonding agent

(b.1) Immediate coating with the bonding agent and then with the base material, wherein the cylinder crankcase is preferably fixed and rotates during the coating process, the plasma torch and moves along the cylinder bore into the cylinder crankcase and back out,

Preferably, this process is carried out once to apply the adhesion promoter and then applied one to five times, preferably three times to the desired layer thickness of the base material, or wherein the coating is effected by means of wire spraying,

or (b.2) coating with a mixture of adhesion promoter and base material, preferably by means of plasma powder spraying, wherein the cylinder crankcase is preferably fixed and rotates during the coating process, the plasma torch and moves along the cylinder bore in the cylinder crankcase and back out, preferably four times, in Dependency of the desired

Layer thickness can be varied.

Coating the base material by means of a thermal coating process on the pre-formed coating.

Cut bevels at both ends of the cylinder bore.

Honing to measure.

The process of thermal coating is preferably carried out without active air conditioning. The cylinder crankcase heats up during the process, i. during coating, for example, by molten plasma powder and cools down again automatically. After coating, the cylinder crankcase is approx. 100 ° C to a maximum of 140 ° C warm

Preferably, the cylinder crankcase is upright for coating and received on the sump side. During mechanical processing, inter alia fine spindles and chamfers, the cylinder crankcase is preferably on the top deck

added. For the other processing steps, the cylinder crankcase may preferably also be received on the transmission side.

Another aspect of the invention relates to a cylinder crankcase with a cylinder bore having a coating. The coating of the component according to the invention has a first layer which is arranged on a surface of the cylinder bore and which has a first layer

Base material and / or an adhesion promoter of molybdenum and an aluminum-containing alloy. On the first layer, a second layer, which comprises the base material but not the adhesion promoter, is arranged. According to the invention, the second layer is optional if the first layer comprises both the base material and the adhesion promoter. The component according to the invention has a coating, which on the one hand the

Rub resistance of the coated surface greatly improved and at the same time a high

Has durability, because the coating has a very good adhesion on the

Workpiece surface shows. Adhesive tensile values of 50 to> 70 MPa are achieved with the method according to the invention. Thus, the adhesion values of a conventional process in which the adhesion of the coating by prior roughening of the surface and without Adhesive is achieved, reached from 20 to> 70 MPa and even exceeded in the lower range.

The first and second layers are preferably applied to the workpiece surface by a thermal coating process. Preferably, the workpiece is applied by the method according to the invention in one of the previously described embodiments.

The cylinder crankcase according to the invention can be produced by the method described above.

Another aspect of the invention relates to a motor which is an inventive

Cylinder crankcase has.

Further preferred embodiments of the invention will become apparent from the remaining, mentioned in the dependent claims characteristics.

The various embodiments of the invention mentioned in this application are, unless otherwise stated in the individual case, advantageously combinable with each other.

The invention is described below in embodiments with reference to the associated

Drawings explained. Show it:

Figure 1 is a photomicrograph of a cross-section of a coated

Workpiece according to a first embodiment of the invention,

Figure 2 is a photomicrograph of a cross-section of a coated

Workpiece according to a second embodiment of the invention,

Figure 3 is a photomicrograph of a cross-section of a coated

Workpiece according to a third embodiment of the invention,

Figure 4 is a photomicrograph of a cross-section of a coated

Workpiece according to a fourth embodiment of the invention, Figure 5 is a photomicrograph of a cross section of a coated

Workpiece according to a fifth embodiment of the invention, and

Figure 6 is a photomicrograph of a cross section of a coated

Workpiece according to a sixth embodiment of the invention.

Figures 1 to 6 show light microscope images of cross sections (longitudinal sections) of a coated workpiece 1 (cylinder bore) of a component 10 (cylinder crankcase) in different embodiments. In this case, a part of the workpiece 1 is shown, on the metallic surface of which a coating 2 is arranged. The coating 2 can be applied, for example, with the method according to the invention.

The workpiece 1 shown in Figure 1 comprises a metallic surface of a

Light metal alloy, more precisely an aluminum-containing alloy, namely AISi ₁₇ . On this surface, the coating 2 was applied in one process step. The coating 2 shown in Figure 2 comprises a low alloy steel as a base material and a bonding agent which is integrated in the layer. The coating 2 shown in FIG. 1 was produced by the method according to the invention by applying a powder mixture of base material and adhesion promoter to the metallic surface by means of plasma spraying. In the process, the particles of the powder mixture melted and bonded to form a uniform mixed layer 3 on the surface. Since base material and adhesion promoter were already intimately mixed before or during the process of plasma spraying, the workpiece 1 shown in FIG. 1 has a single-layer coating 2, in which the primer in the base material is homogeneously distributed in the farthest and thus forms an integrated primer.

FIG. 2 shows a workpiece 1 which has the same coating 2 as the workpiece 1 shown in FIG. However, the surface of the workpiece 1 is made of gray cast iron.

FIGS. 3 and 4 each show a light microscope photograph of a cross section (longitudinal section) of a coated workpiece 1 according to a further embodiment of the invention. Figures 3 and 4 each show a workpiece 1 with a two-layer coating 2. The coating 2 here comprises a mixed layer 3, which comprises a mixture of the base material and the adhesion promoter. The mixed layer 3 essentially corresponds to the mixed layer 3 of the embodiment shown in FIGS. 1 and 2, but is different from it

Layer thicknesses between 20 and 55 μηη significantly thinner running. On the mixed layer 3 of base material and adhesion promoter, a base material layer 4 is arranged, which in the Essentially consists of the base material. This is many times thicker than the mixed layer 3. Preferred layer thicknesses are in Pulverplasmaspritzschichten in the range of 120 to 180 μηη, in particular in the range of 140 to 160 μηη and a maximum of 300 μηη, and in wire spraying preferably in the range of 150 to 300 μηη, in particular in the range of 170 to 250 μηη, up to a maximum of 500 μηη. The mixed layer 3 has the function of increasing the adhesion of the coating 2, while the base material layer 4 determines the properties of the workpiece to the outside, such as the friction resistance. FIGS. 3 and 4 differ in the material of the coated workpiece. While the

Coating 2 in FIG. 3 is arranged on a light metal alloy, for example an aluminum-containing alloy such as AISi ₁₇ , the material of the workpiece 1 of the embodiment shown in FIG. 4 is a gray cast iron.

The coatings 2 shown in FIGS. 3 and 4 can be applied by the method according to the invention. For this purpose, a powder mixture of adhesion promoter and base material is first provided and arranged on the surface of the workpiece 1 by means of a thermal coating method, such as plasma spraying, so that a homogeneous mixed layer 3 is formed. Subsequently, a powder which contains the base material but not the adhesion promoter is provided and likewise applied to the mixed layer 3 by a, preferably the same, thermal process. For a simple realization, the device which carries out the thermal coating method can be used with a

Double powder conveyor be equipped, making the same device for both

Coating steps can be used.

FIGS. 5 and 6 likewise each show a light microscope photograph of a cross section (longitudinal section) of a coated workpiece 1 according to further embodiments of FIGS

Invention. Figures 5 and 6 show the same coating 2, but differ in the material of the workpiece 1, which in Figure 5, a light metal alloy (in particular AISii ₇ ) and in the workpiece 1 of Figure 6 comprises a gray cast iron. The coating 2 of the embodiment shown in Figures 5 and 6 is also a two-layered system

formed, wherein the first arranged on the workpiece surface layer is a primer 5 on which a base material layer 6 is deposited, which contains the base material. In this embodiment, the primer 5 comprises the primer and contains no

Base material.

The base material of the illustrated embodiments is a low-alloy steel such as (preferably iron-based steel having 0.05 to 1.5 wt% carbon; 0.05 to 3.5% by weight of manganese; 0.05 to 3.0% by weight of chromium; 0.01 to 1% by weight of silicon and / or 0.001 to 0.4% by weight of sulfur and / or a chromium steel having an iron base and 0.05 to 0.8% by weight of carbon; 0-3% by weight of molybdenum; 0.05 to 1 .8% by weight of manganese; 1 1.5 to 18% by weight of chromium; 0.01 to 1% by weight of silicon and / or 0.002 to 0.2% by weight of sulfur. The ratio of adhesion promoter and base material in the mixed layers 3 of FIGS. 1 to 4 preferably has a ratio of 20% by weight of adhesion promoter to 80% by weight of base material. In principle, the adhesion promoter is present in a range from 10 to 80% by weight and the base material in the range from 20 to 90% by weight in the mixed layer 3.

The coupling agent in all embodiments shown is a mixture of molybdenum and a Ni5AI alloy (95% nickel and 5% aluminum) or a mixture of molybdenum NiAl alloy and the base material as described above. Alternatively, nickel in the aluminum-containing alloy may be replaced by cobalt, copper or silver. In this case, molybdenum to 20 to 80 wt .-% and the aluminum-containing alloy in a range of 20 to 80 wt .-% in the adhesion promoter.

Alternatively or additionally, such layers can also be produced by means of wire-spraying methods such as LDS, PTWA and RSW by positioning the adhesion promoter in a flux-cored wire or by spraying wire-spraying layers onto a primer applied by a plasma spraying process.

LIST OF REFERENCE NUMBERS

Component (cylinder crankcase) workpiece (cylinder liner)

coating

Mixed layer of base material and primer base material layer

Primer / first layer

Base material layer / second layer

Claims

claims

A method of coating the cylinder liner (1) of a cylinder crankcase (10) comprising the steps

a: Providing a powdery base material and a powdery

Adhesion promoter, wherein the adhesion promoter is a mixture of molybdenum (Mo) and a

Aluminum-containing alloy (A (X) AI), and

b: Applying the base material and the adhesion promoter to the cylinder liner (1) of the

Cylinder crankcase (10) by means of a thermal coating process, either

by applying a layer (3) of a powder mixture of adhesion promoter and base material, or

Applying a first layer (5) comprising the adhesion promoter and then applying a second layer (6) comprising the base material to the first layer (5).

A method according to claim 1, characterized in that the aluminum-containing

Alloy besides aluminum contains nickel (Ni), copper (Cu), cobalt (Co), silver (Ag) and / or boron (B).

Method according to one of the preceding claims, characterized in that Mo is present in the range of 20 to 80 wt .-% and / or the aluminum-containing alloy in the range of 20 to 80 wt .-% based on the adhesion promoter.

Method according to one of the preceding claims, characterized in that the base material comprises iron or an iron alloy, in particular steel.

Method according to one of the preceding claims, characterized in that the adhesion promoter and the base material in a weight ratio of 10/90, 20/80, 30/70, 40/60 or 50/50 are present in the powder mixture.

Method according to one of the preceding claims, characterized in that the method comprises a further step (c), in which a layer (4) of the Base material is applied by thermal coating process on the coating produced in step (b).

7. The method according to any one of the preceding claims, characterized in that the adhesion promoter comprises Ni (95%) Al (5%).

8. The method according to any one of the preceding claims, characterized in that the cylinder bore (1) to be coated consists of gray cast iron.

9. The method according to any one of the preceding claims, characterized in that the thermal coating method is plasma spraying.

10. The method according to any one of the preceding claims, characterized in that the thermal coating method is wire spraying, wherein after step b) the application of the base material and the adhesion promoter by applying a first layer (5) comprising the adhesion promoter and then applying a second layer (6 ) comprising the base material on the first layer (5).

1 1. A method according to any one of the preceding claims, characterized in that the method is no pretreatment of the surface of the cylinder bore (1), in particular no roughening of the cylinder bore (1) of the cylinder crankcase (10).

12. Cylinder crankcase (10) with a cylinder bore (1) having a coating (2)

having the coating (2)

a layer (3, 5) arranged on a surface of the cylinder liner (1), comprising a base material and / or an adhesion promoter of molybdenum (Mo) and an aluminum-containing alloy (A (X) Al), and

if the first layer comprises both the base material and the adhesion promoter, a further layer (6) arranged on the layer (5) and comprising the base material but not the adhesion promoter,

having.

13. Cylinder crankcase (10) with a cylinder bore (1) having a coating (2)

produced by the method according to any one of claims 1 to 11.

14. Engine a cylinder crankcase (10) according to claim 12 or 13.