JP6486978B2 - Laminated member, and impeller, compressor and engine using the same - Google Patents

Description

The present invention relates to a laminated member, and an impeller, a compressor, and an engine using the same.

  For example, as shown in Patent Document 1, there is a low pressure exhaust gas recirculation (EGR) system for reducing NOx in exhaust gas in a marine engine. This low-pressure EGR system returns a partial recirculation gas of the low-pressure exhaust gas discharged from the supercharger outlet of the main engine to the exhaust pipe to the supercharger inlet. As a result, the oxygen concentration of the combustion gas decreases, the combustion speed, which is a reaction between the fuel and oxygen, is delayed, and the combustion temperature decreases, so that the amount of NOx generated can be reduced.

  Further, since a marine engine uses a fuel having a large S component, the exhaust gas contains an S component and a Cl component that are corrosive components of the impeller of the compressor of the supercharger. Therefore, the EGR system is provided with a scrubber that removes the S component in the recirculation gas with washing water.

Japanese Patent No. 5916772 Japanese Patent No. 5882001

However, the S component may remain in the recirculation gas even when the recirculation gas is washed with a scrubber. Moreover, the droplets contained in the recirculated gas after washing is removed in the demister unit arranged downstream of the scrubber, the water in the recycle gas passed through the demister units turbocharger compressor May condense before reaching.

  The droplet condensed in the recirculation gas contains the S component and the Cl component, so that the hydrogen ion concentration (pH) becomes about 1-2. Here, a lightweight and high-strength Al alloy substrate is used for the impeller of the compressor of the supercharger, but the Al alloy substrate is corroded by droplets contained in the recirculation gas (corrosion). May occur).

The droplets condensed in the recirculation gas collide with the impeller of the compressor . As a result, the impeller may be plastically deformed and may be worn away (erosion may occur) due to repetition thereof.

  As a first countermeasure against the above problem, a method of anodizing the Al alloy base material of the impeller can be considered, but this method may not provide sufficient erosion resistance and corrosion resistance. .

  Further, as a second countermeasure against the above problem, a method of coating a ceramic layer on the surface of the Al alloy substrate of the impeller by a physical vapor deposition method or a chemical vapor deposition method is conceivable. This ceramic layer becomes a highly hard film having corrosion resistance. However, in this method, when a liquid droplet collides with the ceramic layer, the impact is transmitted to the inner Al alloy base material, and the Al alloy base material is deformed, thereby causing a crack in the ceramic layer. There is a risk that the Al alloy substrate will peel off. In addition, the droplets may permeate the Al alloy substrate from the cracked or peeled portion and corrode the Al alloy substrate. Furthermore, there is a possibility that a defect is present in the ceramic layer from the beginning (at the time of coating film formation), and the droplets penetrate into the Al alloy substrate from the defect and corrode the Al alloy substrate.

  Furthermore, as a third countermeasure against the above problem, a method of performing electroless plating such as Ni-P alloy on the surface of the Al alloy substrate of the impeller can be considered. However, a slight amount of S component is contained in the plating film. Therefore, the corrosion resistance may not be sufficiently obtained.

In view of the above technical problems, an object of the present invention is to provide a laminated member having both erosion resistance and corrosion resistance, and an impeller, a compressor, and an engine using the same.

The laminated member according to the first invention for solving the above problems is
An Al alloy substrate;
An electroless plating layer formed on the surface of the Al alloy substrate;
Si layer formed on the surface of the electroless plating layer;
A diamond-like carbon layer formed on the surface of the Si layer ,
The electroless plating layer is harder than the Al alloy substrate, and the Si layer has an intermediate hardness between the diamond-like carbon layer and the electroless plating layer .

The laminated member according to the second invention for solving the above problems is
An Al alloy substrate;
An electroless plating layer formed on the surface of the Al alloy substrate;
Si layer formed on the surface of the electroless plating layer;
A diamond-like carbon layer formed on the surface of the Si layer;
And a polymer electrodeposition layer formed on the surface of the diamond-like carbon layer .

The laminated member according to the third invention for solving the above problem is
In the laminated member according to the second invention,
The electroless plating layer is harder than the Al alloy substrate, and the Si layer has an intermediate hardness between the diamond-like carbon layer and the electroless plating layer .

An impeller according to a fourth invention for solving the above-described problem is
It is formed by the laminated member according to any one of the first to third aspects.

A compressor according to a fifth invention for solving the above-described problem is
The impeller according to the fourth invention,
And a compressor casing for accommodating the impeller therein.

An engine according to a sixth invention for solving the above-described problem is
The engine body,
A compressor according to the fifth aspect of the invention connected to the air supply side of the engine body, and a supercharger having a turbine connected to the compressor and connected to the exhaust side of the engine body;
An EGR system connected between an exhaust side of the turbine and an air supply side of the compressor is provided.

The laminated member according to the present invention, and the impeller, compressor, and engine using the laminated member can have both erosion resistance and corrosion resistance.

It is the schematic explaining the engine and compressor which concern on this invention. It is typical sectional drawing explaining the laminated member which concerns on Example 1 of this invention. It is typical sectional drawing explaining the laminated member which concerns on Example 2 of this invention. It is typical sectional drawing explaining the laminated member which concerns on the reference example 1 of this invention. It is typical sectional drawing explaining the laminated member which concerns on the reference example 2 of this invention.

  FIG. 1 is a schematic diagram illustrating an engine and a compressor according to the present invention. As shown in FIG. 1, an engine (marine engine 10) according to the present invention includes an engine body 11, a supercharger 12, an air cooler (cooler) 13, and an EGR system 14.

  The engine body 11 is, for example, a uniflow scavenging exhaust type diesel engine and is a two-stroke diesel engine. The scavenging exhaust flow in the cylinder 11a is made to flow in one direction from below to eliminate exhaust residue. It is a thing. The engine body 11 uses a fuel having a large S component. The engine body 11 supplies the combustion gas in the scavenging trunk 11b to the cylinder 11a, burns it with fuel in the cylinder 11a, and discharges the exhaust gas generated by the combustion from the cylinder 11a to the exhaust manifold 11c. The scavenging trunk 11b of the engine body 11 of the present invention is connected to an air supply pipe G1, and the exhaust manifold 11c is connected to an exhaust pipe G2.

  The supercharger 12 is connected to the compressor (compressor 21) connected to the scavenging trunk 11b of the engine body 11 and the turbine 22 connected to the exhaust manifold 11c of the engine body 11 via a rotating shaft so as to rotate integrally. Connected to each other. In the supercharger 12, the turbine 22 is rotated by exhaust gas flowing from the exhaust pipe G <b> 2 connected to the engine body 11, and the rotation of the turbine 22 is transmitted to rotate the compressor 21. As the compressor 21 rotates, the combustion gas is compressed, and the compressed combustion gas is supplied to the engine body 11 through the supply air pipe G1.

  The compressor 21 includes a compressor casing (not shown) and an impeller (not shown). The compressor casing guides the combustion gas compressed by the compressor to the impeller and guides the compressed combustion gas to the supply air pipe G1. The impeller is provided inside the compressor casing and is configured to be rotatable about the rotation axis. The impeller is formed of an environment-resistant member, which will be described later, based on an Al alloy (for example, JIS A2618). A silencer 21 a is further connected to the combustion gas inlet side of the compressor 21.

  The silencer 21a is a cylindrical device provided with a plurality of silencer elements (not shown) in the circumferential direction. The silencer is configured so that noise generated by driving the compressor 21 does not escape to the engine room in which the engine body 11 is disposed. Furthermore, the silencer 21 a forms a passage for guiding combustion gas to the compressor 21. Here, the silencer 21a has a path for guiding the air in the engine room from between the silencer elements to the compressor 21 as combustion air, and in the exhaust gas recirculation pipe G6 for guiding the recirculated gas to the compressor 21 from the axial direction of the silencer 21a. It is connected. During EGR operation, combustion gas is generated by mixing the recirculation gas from the exhaust gas recirculation pipe G6 and the combustion air.

  The turbine 22 is connected to an exhaust pipe G3 that discharges exhaust gas that has rotated the turbine 22, and the exhaust pipe G3 is connected to a chimney (funnel) via an exhaust gas treatment device (not shown).

  The air cooler 13 cools the combustion gas by exchanging heat between the combustion gas compressed by the compressor 21 and the high temperature and the cooling water, thereby increasing the oxygen density in the combustion gas.

  The EGR system 14 includes exhaust gas recirculation pipes G4, G5, G6, a scrubber 23, a demister unit 24, and an EGR blower 25, and is connected between the exhaust side of the turbine 22 and the supply side of the compressor 21. Yes. The EGR system 14 recirculates a part of the exhaust gas discharged from the engine body 11 and passed through the turbine 22 to the engine body 11 as a recirculation gas. The recirculated gas, after removing harmful substances, is mixed with combustion air, and then compressed by the compressor 21 to be recirculated to the engine body 11 as a combustion gas.

  The scrubber 23 removes harmful substances such as contained SOx (S component) and fine particles (PM) such as dust by injecting liquid to the recirculation gas. The scrubber 23 is connected to an exhaust gas recirculation pipe G5 that discharges the recirculated gas and the drainage liquid from which harmful substances have been removed.

  The demister unit 24 separates the recirculated gas from which harmful substances have been removed from the drainage liquid, and removes droplets in the recirculated gas. Further, the demister unit 24 is provided with a drainage circulation pipe W1 for circulating the drainage to the scrubber 23. The drain circulation pipe W1 is provided with a hold tank 31 for temporarily storing the drainage and a pump 32.

  The EGR blower 25 guides the recirculation gas from the scrubber 23 to the demister unit 24 from the exhaust gas recirculation pipe G5.

In the engine according to the present invention, a laminated member according to the present invention having both erosion resistance and corrosion resistance is used for the impeller of the compressor 21.

The engine according to the present invention is not limited to a marine engine, and can be applied to all engines having a low pressure EGR system.
Hereinafter, the laminated member concerning this invention is demonstrated using drawing in each Example and a reference example .

[Example 1]
FIG. 2 is a schematic cross-sectional view illustrating the laminated member according to this example. As shown in FIG. 2, the laminated member according to this example includes an Al alloy substrate 41, an electroless plating layer 42 formed on the surface of the Al alloy substrate 41 (upper side in the figure; the same applies hereinafter), electroless plating. An Si layer 43 formed on the surface of the layer 42 and a diamond-like carbon (DLC) layer 44 formed on the surface of the Si layer 43 are provided.

  As a specific example, the electroless plating layer 42 uses electroless Ni-P plating or electroless Ni-B plating, or electroless Ni-P plating or electroless Ni-B plating in which SiC or other hard particles are combined. . In addition, by combining SiC and other hard particles with electroless plating, the hardness is increased and deformation is more difficult.

  The electroless plating layer 42 is plated with a reduced S component. This is realized by using a plating solution using a stabilizer having a low S component and a surfactant in the step of forming the plating.

The laminated member according to the present embodiment can have both erosion resistance and corrosion resistance by adopting the above configuration. That is, by forming the electroless plating layer 42 and the DLC layer 44 on the surface of the Al alloy base material 41, it is possible to prevent the occurrence of cracking due to the collision of the droplets. That is, by providing the hard DLC layer 44, erosion resistance and corrosion resistance can be ensured.

  Further, the electroless plating layer 42 can improve the corrosion resistance of the electroless plating layer 42 itself by reducing the S component. The electroless plating layer 42 is not limited to the material thereof, and an amorphous film of Ni—P or Ni—B compound can be applied.

Furthermore, the laminated member according to this example provided the Si layer 43 between the DLC layer 44 and the electroless plating layer 42, thereby reaching the penetration defect (the surface of the Al alloy base material 41 during coating film formation) Corrosion due to defects) can be prevented.

  Further, if the electroless plating layer 42 is not provided, even if the DLC layer 44 has erosion resistance, the Al alloy substrate 41 on the inner side (lower side in the figure, the same applies hereinafter) is deformed at the time of droplet collision. As a result, the DLC layer 44 is deformed and causes cracking. Therefore, in this embodiment, by providing an electroless plating layer 42 that is harder than the Al alloy substrate 41 between the Al alloy substrate 41 and the DLC layer 44, deformation of the upper DLC layer 44 is suppressed. The occurrence of cracks can be prevented. In other words, the DLC layer 44 has a small effect of preventing the occurrence of cracks in a single layer, but the occurrence of cracks can be prevented by forming the electroless plating layer 42 on the inner side.

  Then, by providing the Si layer 43 between the DLC layer 44 and the electroless plating layer 42, adhesion with the electroless plating is ensured (Si having intermediate hardness between the DLC layer 44 and the electroless plating layer 42). Adhesion is improved by the layer 43), and penetration defects of the DLC layer 44 can be prevented.

  Since the DLC layer 44 is formed by a chemical vapor deposition method using Si-based gas, the Si layer 43 is used as the layer provided between the DLC layer 44 and the electroless plating layer 42 as described above. The adhesion with the electroless plating layer 42 can be improved. In this respect, in Patent Document 2, since it is an intermediate layer of a compound containing Si in carbon, the adhesion with the plating layer cannot be improved as compared with the present example.

  This point will be described in detail. The reason why the Si layer 43 is used on the surface of the electroless plating layer 42 is to provide a layer having a hardness intermediate between the plating layer 42 and the DLC layer 44 toward the surface layer. This is because the hardness is increased stepwise to prevent peeling at the interface of each layer. Compared to the Si-containing carbon compound layer of Patent Document 2 described above, this configuration enables an even increase in hardness, increases the response to deformation against impact force at the time of droplet collision, and The ability to prevent peeling will increase.

[Example 2]
FIG. 3 is a schematic cross-sectional view illustrating the laminated member according to this example. As shown in FIG. 3, the laminated member according to the present embodiment includes an Al alloy base 41, an electroless plating layer 42 formed on the surface of the Al alloy base 41, and a surface of the electroless plating layer 42. Si layer 43, DLC layer 44 formed on the surface of Si layer 43, and polymer electrodeposition layer 61 formed on the surface of DLC layer 44.

That is, the laminated member according to the present example is obtained by forming the polymer electrodeposition layer 61 on the surface of the DLC layer 44 that is the outermost surface portion of the laminated member according to the first example.

  As a specific example of the polymer electrodeposition layer 61, epoxy, polyimide, fluorine, or polyimide amide material is used. The thickness of the polymer electrodeposition layer 61 is 5 μm or more. This is because defects may occur when the thickness is less than 5 μm. More preferably, it is 10-40 micrometers. In addition, since it is an electrodeposition layer, the upper limit on manufacture is about 50 micrometers.

  Furthermore, the surface of the DLC layer 44 is subjected to shot blasting with fine particles or a shot with media containing hard ceramic particles in viscoelastic particles. By forming the polymer electrodeposition layer 61 thereon, the adhesion between the polymer electrodeposition layer 61 and the DLC layer 44 can be improved.

  The polymer electrodeposition layer 61 thus provided has a role of relaxing the impact force of the droplets and a role of improving the corrosion resistance. Furthermore, corrosion due to penetration defects during coating film formation can be prevented more reliably.

[ Reference Example 1 ]
FIG. 4 is a schematic cross-sectional view illustrating a laminated member according to this reference example. As shown in FIG. 4, the laminated member according to this reference example includes an Al alloy base 41, an electroless plating layer 42 formed on the surface of the Al alloy base 41, and a surface of the electroless plating layer 42. And a ceramic layer 54 formed on the surface of the corrosion-resistant metal layer 53.

  As a specific example, the electroless plating layer 42 uses electroless Ni-P plating or electroless Ni-B plating, or electroless Ni-P plating or electroless Ni-B plating in which SiC or other hard particles are combined. . The electroless plating layer 42 is plated with a reduced S component. This is realized by using a plating solution using a stabilizer having a low S component and a surfactant in the step of forming the plating. These points are the same as in the first embodiment.

  The ceramic layer 54 is specifically made of nitride or carbonitride such as CrN, TiN, TiCN or TiAlN. As a specific example of the corrosion-resistant metal layer 53, Cr is used when the ceramic layer 54 contains Cr, and Ti is used when the ceramic layer 54 contains Ti.

The laminated member according to this reference example can have both erosion resistance and corrosion resistance by adopting the above-described configuration. That is, by forming the electroless plating layer 42 and the ceramic layer 54 on the surface of the Al alloy base material 41, it is possible to prevent the occurrence of cracking due to the collision of droplets. That is, by providing the hard ceramic layer 54, it is possible to improve the erosion resistance and the corrosion resistance.

  As in Example 1, the electroless plating layer 42 can improve the corrosion resistance of the electroless plating layer 42 itself by reducing the S component.

Furthermore, the laminated member according to this reference example can prevent corrosion due to penetration defects during coating film formation by providing the corrosion-resistant metal layer 53 between the ceramic layer 54 and the electroless plating layer 42.

In addition, if the electroless plating layer 42 is not provided, even if the ceramic layer 54 has erosion resistance, the ceramic layer 54 is deformed by the deformation of the inner Al alloy substrate 41 at the time of droplet collision. Deforms and causes cracking. Therefore, in this reference example, by providing an electroless plating layer 42 that is harder than the Al alloy substrate 41 between the Al alloy substrate 41 and the ceramic layer 54, deformation of the upper ceramic layer 54 is suppressed. The occurrence of cracks can be prevented. That is, although the ceramic layer 54 has a small effect of preventing the occurrence of cracks in a single layer, the formation of cracks can be prevented by forming the electroless plating layer 42 on the inner side.

  Then, by providing a corrosion-resistant metal layer 53 between the ceramic layer 54 and the electroless plating layer 42, adhesion with the electroless plating layer 42 is ensured (an intermediate between the ceramic layer 54 and the electroless plating layer 42). The adhesion is improved by the corrosion-resistant metal layer 53 having hardness), and penetration defects of the ceramic layer 54 can be prevented.

  The ceramic layer 54 is formed by physical vapor deposition. For example, when the ceramic layer 54 is CrN, the Cr plate is melted and deposited by arc discharge, and when the ceramic layer 54 is TiN, the Ti plate is melted and deposited by arc discharge. Therefore, as the corrosion-resistant metal layer 53 provided between the ceramic layer 54 and the electroless plating layer 42, Cr is used when the ceramic layer 54 contains Cr, and Ti is used when the ceramic layer 54 contains Ti. . Thereby, the electroless plating layer 42 and the ceramic layer 54 can be maintained firmly. In this regard, in Patent Document 2, since it is an intermediate layer of a compound containing Si in carbon, adhesion with the ceramic layer 54 cannot be mainly improved.

  Specifically, the reason for providing the Cr layer when the ceramic layer 54 is CrN and the Ti layer when the ceramic layer 54 is TiN is provided on the surface of the electroless plating layer 42. This is because by providing a layer having a hardness intermediate between the respective hardnesses of the layer 54, the hardness is increased stepwise toward the surface layer, and peeling at the interface of each layer is prevented. Compared to the Si-containing carbon compound of Patent Document 2 described above, this configuration enables an even increase in hardness, increases the response to deformation against impact force at the time of droplet collision, and peels between the layers. The prevention ability will increase.

[ Reference Example 2 ]
FIG. 5 is a schematic cross-sectional view illustrating a laminated member according to this reference example. As shown in FIG. 5, the laminated member according to this reference example was formed on the surface of the Al alloy base material 41, the electroless plating layer 42 formed on the surface of the Al alloy base material 41, and the surface of the electroless plating layer 42. A corrosion-resistant metal layer 53, a ceramic layer 54 formed on the surface of the corrosion-resistant metal layer 53, and a polymer electrodeposition layer 61 formed on the surface of the ceramic layer 54 are provided.

That is, the laminated member according to the present reference example, the surface of the ceramic layer 54 is the outermost surface portion of the laminate member according to Reference Example 1, in which the polymer electrodeposition layer 61 is formed.

  A specific example of the polymer electrodeposition layer 61 is an epoxy, polyimide, fluorine, or polyimide amide material as in the second embodiment. The thickness of the polymer electrodeposition layer 61 is 5 μm or more, more preferably 10 to 40 μm.

  Further, the surface of the ceramic layer 54 is shot with fine particles, or shot with media containing hard ceramic particles in viscoelastic particles. By forming the polymer electrodeposition layer 61 thereon, the adhesion between the polymer electrodeposition layer 61 and the ceramic layer 54 can be improved.

  The polymer electrodeposition layer 61 thus provided has a role of relaxing the impact force of the droplets and a role of improving the corrosion resistance. Furthermore, corrosion due to penetration defects during coating film formation can be prevented more reliably.

The present invention is suitable as a laminated member, and an impeller, compressor, and engine using the same.

DESCRIPTION OF SYMBOLS 10 Marine engine 11 Engine main body 12 Supercharger 13 Air cooler 14 EGR system 21 Compressor 22 Turbine 23 Scrubber 24 Demister unit 25 EGR blower 31 Hold tank 32 Pump 41 Al alloy base material 42 Electroless plating layer 43 Si layer 44 DLC layer 53 Corrosion resistance Metal layer 54 Ceramic layer 61 Polymer electrodeposition layer

Claims (6)

An Al alloy substrate;
An electroless plating layer formed on the surface of the Al alloy substrate;
Si layer formed on the surface of the electroless plating layer;
A diamond-like carbon layer formed on the surface of the Si layer ,
Laminating the electroless plating layer, the a harder than Al alloy substrate, and wherein the Si layer is characterized by having an intermediate hardness of the electroless plating layer and the diamond-like carbon layer Element. An Al alloy substrate;
An electroless plating layer formed on the surface of the Al alloy substrate;
Si layer formed on the surface of the electroless plating layer;
A diamond-like carbon layer formed on the surface of the Si layer;
A laminated member comprising: a polymer electrodeposition layer formed on a surface of the diamond-like carbon layer . The electroless plating layer is harder than the Al alloy substrate, and the Si layer has an intermediate hardness between the diamond-like carbon layer and the electroless plating layer. Item 3. The laminated member according to Item 2. An impeller formed by the laminated member according to any one of claims 1 to 3 . An impeller according to claim 4 ;
And a compressor casing for accommodating the impeller therein. The engine body,
The compressor according to claim 5 connected to an air supply side of the engine body, and a supercharger having a turbine connected to the compressor and connected to an exhaust side of the engine body;
An engine comprising: an EGR system connected between an exhaust side of the turbine and an intake side of the compressor.

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