KR102583763B1 - Assembly for fuel injector and coating method for the same - Google Patents

Abstract

The present invention relates to fuel injector parts and a coating method thereof. Specifically, zirconium is added to the ta-C(:H)-Zr functional layer in a gradient structure to improve bonding strength with the bonding layer/support layer and ta-C Provided are fuel injector parts with excellent low friction, heat resistance, and corrosion resistance on the outer surface of the (:H)-Zr functional layer, and a coating method thereof.

Description

Parts for fuel injectors and their coating method {ASSEMBLY FOR FUEL INJECTOR AND COATING METHOD FOR THE SAME}

The present invention relates to fuel injector parts and a coating method thereof, and more specifically, to a fuel injector part and a coating method thereof in which a coating material is laminated to reduce frictional resistance, increase coating hardness and durability.

A car's fuel injector is one of the key components that supplies fuel to the engine in a timely manner according to the engine's stroke.

In relation to this, among fuel injector parts, especially sliding parts, balls and valve seats are becoming smaller, but due to improvements in engine performance, they are exposed to higher and repetitive loads and stresses, and their lifespan is rapidly reduced due to thermal shock and wear. phenomenon occurs.

As a way to improve the wear resistance of these sliding parts, a bonding layer is formed on the base material of the sliding parts, a support layer is formed on the surface of the bonding layer, and a functional layer is formed on the surface of the support layer to improve the wear resistance and heat resistance of the sliding parts. There are ways to improve.

Meanwhile, Korean Patent Publication No. 10-2015-0057249 discloses a technology that improves the base material with DLC by using chromium as an intermediate layer to ensure wear resistance and coating the surface layer with DLC (Diamond-Like Carbon) to form a gradient. It is done.

However, after coating chrome, when CH ₄ gas and C ₂ H ₂ gas are used to form DLC, despite its high durability, heat resistance is low and the surface may peel off or particles may be generated during the operation of driving parts such as fuel injectors. There is a problem that durability is reduced due to the problem.

Korean Patent Publication No. 10-2015-0057249

The present invention was created to improve problems such as performance degradation and replacement costs caused by wear of sliding parts due to improved engine performance when applying the conventional fuel injector parts and their coating method as described above, using zirconium. By adding it to ta-C(:H) in a gradient structure, the bonding strength with the bonding layer/support layer is improved, and it provides fuel injector parts with excellent low friction, heat resistance, and corrosion resistance on the external surface of ta-C(:H). There is a purpose.

In addition, the purpose is to provide a coating method for fuel injector parts that provides precise coating to necessary areas of ultra-small parts.

In order to achieve the above-described object, a fuel injector component according to the first embodiment of the present invention includes a base material; A bonding layer laminated on the surface of the base material; A support layer laminated on the outer surface of the bonding layer; and a ta-C(:H)-Zr functional layer laminated on the outer surface of the support layer, wherein the ta-C(:H)-Zr functional layer has a zirconium composition gradient toward the surface.

The bonding layer may be formed by applying an arc discharge to a target containing zirconium and depositing evaporated metal ions on the base material.

The support layer may be formed by depositing metal nitride particles on the bonding layer, which are formed by reacting metal ions evaporated by applying an arc discharge to a target containing zirconium and nitrogen ions separated from nitrogen gas injected as an active gas. there is.

The ta-C(:H)-Zr functional layer may be formed by simultaneously applying an arc discharge to a target containing graphite and a target containing zirconium, thereby stacking evaporated carbon particles and zirconium particles on the support layer.

The ta-C(:H)-Zr functional layer may contain more than 0 atomic% but not more than 20 atomic% zirconium and more than 0 atomic% but less than 30 atomic% hydrogen, and the balance may be made up of carbon and inevitable impurities.

The ta-C(:H)-Zr functional layer may have a composition gradient in which the zirconium composition continuously increases toward the surface.

In addition, in order to achieve the above-described object, the coating method for fuel injector parts according to the second embodiment of the present invention is to laminate a multi-layered coating material on the surface of the base material of the fuel injector part. A base material mounting step of mounting the inside of the reaction chamber; A bonding layer forming step of stacking a bonding layer on the outer peripheral surface of the base material; A support layer forming step of laminating a support layer on the outer surface of the bonding layer; It includes a functional layer forming step of laminating a ta-C(:H)-Zr functional layer on the outer surface of the support layer.

In the bonding layer forming step, an arc discharge is applied to a target containing zirconium, and evaporated metal ions move to the surface of the base material to form a metal layer.

In the support layer forming step, metal ions evaporated by applying an arc discharge to a target containing zirconium react with nitrogen ions separated from nitrogen gas injected as an active gas, and the metal nitride particles formed move to the surface of the base material to form a metal nitride layer. can be formed.

In the functional layer forming step, an arc discharge is simultaneously applied to a target containing graphite and a target containing zirconium, so that evaporated carbon particles and zirconium particles are stacked on the support layer to form a ta-C(H)-Zr functional layer. can do.

In the functional layer forming step, the current applied to the target containing the graphite is continuously changed in the range of 60A to 100A, and the current applied to the target containing zirconium is continuously changed in the range of 80A to 110A. can do.

In addition, the coating method of fuel injector parts according to the second embodiment of the present invention is a vacuum in which, after the base material mounting step, the internal atmosphere of the chamber is maintained in a vacuum state while the base material is placed inside the chamber. formation stage; A plasma forming step of injecting Ar gas into the reaction chamber and raising the temperature of the chamber to form a plasma state in which Ar ions are generated; and a cleaning step of colliding the Ar ions with the surface of the base material to clean the surface of the base material.

As described above, the fuel injector parts and coating method according to the present invention have the effect of improving friction reduction, high hardness, impact resistance, heat resistance, and durability of the fuel injector parts.

Additionally, durability, heat resistance, and impact resistance can be maintained with only a thin coating.

1 is a partially enlarged view of a fuel injector equipped with fuel injector parts according to the present invention.
Figure 2 is a schematic diagram showing a cross section of a fuel injector component on which a coating material deposited according to the first embodiment of the present invention is laminated.
Figure 3 is a scanning electron microscope (SEM) photograph of a coating material deposited according to the first embodiment of the present invention.
Figure 4 is a flowchart for explaining a method of coating fuel injector parts according to a second embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. This is not intended to limit the present invention to specific embodiments, and should be interpreted as including all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention.

In describing the present invention, terms such as first and second may be used to describe various components, but the components may not be limited by the terms. The above terms are solely for the purpose of distinguishing one component from another. For example, a first component may be named a second component, and similarly, the second component may also be named a first component without departing from the scope of the present invention.

The term “and/or” may include any of a plurality of related stated items or a combination of a plurality of related stated items.

When a component is said to be "connected" or "connected" to another component, it means that it may be directly connected to or connected to that other component, but that other components may also exist in between. It can be understood. On the other hand, when a component is referred to as being “directly connected” or “directly connected” to another component, it can be understood that there are no other components in between.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions may include plural expressions, unless the context clearly indicates otherwise.

In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and one or more other features It can be understood that it does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries can be interpreted as having meanings consistent with the meanings they have in the context of related technologies, and unless clearly defined in this application, are interpreted as having an ideal or excessively formal meaning. It may not work.

In addition, the following examples are provided to provide a more complete explanation to those with average knowledge in the art, and the shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

1 shows a partially enlarged view of a fuel injector equipped with fuel injector parts according to a first embodiment of the present invention.

Referring to FIG. 1, the fuel injector includes a housing that accommodates a needle therein, a valve seat (C) formed at the bottom of the housing, and a ball (A) disposed between the valve seat (C) and the needle (B). .

The valve seat (C) has a valve seat surface on which the ball (A) is seated, and a nozzle penetrating the valve seat (C) in the fuel injection direction is provided.

The needle (B) opens and closes the nozzle formed on the valve seat (C) while moving the ball (A) in the vertical direction under the action of a magnetic coil and return spring (not shown).

Although a ball A having a spherical shape is shown in Figure 1, the present invention is not limited to this, and other valve elements having various shapes can be applied without limitation, and all of them will be considered to fall within the scope of the present invention. For convenience, the following description will be based on an embodiment of a ball (A) having a spherical shape.

Fuel injectors, especially direct injection type fuel injectors, inject fuel directly into the cylinder, so the ball (A) and valve seat (C) are exposed to high temperature and pressure, and the nozzle is exposed to combustion by-products such as carbon monoxide and soot. There is a high possibility that phenomena such as blockage will occur.

In this way, the ball (A) and valve seat (C) are exposed to high temperature and high pressure, and generate a large frictional resistance due to combustion by-products, so they can be easily damaged by deterioration phenomena such as creep or oxidation due to repeated driving. Therefore, the present invention is configured to reduce frictional resistance, increase durability, and increase heat resistance by laminating a multi-layered coating material on the base material 100 of the ball (A) and valve seat (C) as shown in Figure 2. do.

Figure 2 shows a schematic diagram showing a cross section of a fuel injector component on which a coating material deposited according to the first embodiment of the present invention is laminated, and Figure 3 shows a coating material deposited according to the first embodiment of the present invention. A SEM (Scanning Electron Microscope) photograph of a cross-section of a fuel injector part is disclosed.

2 and 3, the fuel injector component according to the first embodiment of the present invention includes a base material 100, a bonding layer 200 laminated on the surface of the base material 100, and the bonding layer 200. It includes a support layer 300 laminated on the outer surface of the support layer 300 and a ta-C(:H)-Zr functional layer 400 laminated on the outer surface of the support layer 300, wherein the ta-C(:H)-Zr The functional layer 400 is characterized in that a compositional gradient of zirconium is formed in the surface direction.

In detail, a multi-layer coating material is formed on the base material 100 in which the bonding layer 200, the support layer 300, and the ta-C(:H)-Zr functional layer 400 are sequentially stacked. , the durability of fuel injector parts can be increased.

In the first embodiment, the base material 100 is formed in a spherical shape to be used in an injector ball, but is not limited thereto, and includes all forms formed in various shapes so as to be applicable to various parts used in an injector valve seat and a high pressure pump. can do.

The material of the base material 100 may be a metal with improved corrosion resistance, including stainless steel, iron containing chromium, or aluminum, and metal materials included in conventionally known technologies may be used.

The bonding layer 200 may be laminated on the outer side of the base material 100, and the support layer 300 may be laminated on the outer surface of the bonding layer 200.

Specifically, in this embodiment, zirconium (Zr) was used as a material for the bonding layer 200 and zirconium nitride (ZrN) was used as a material for the support layer 300, but the present invention is not limited thereto. Titanium (Ti), tungsten (W), chromium (Cr), or molybdenum (Mo) is used as a material for the bonding layer 200, and titanium nitride (TiN) and tungsten (WN) are used as a material for the support layer 300. , chromium nitride (CrN) or molybdenum nitride (MoN) can be used.

At this time, the bonding layer 200, the support layer 300, or the ta-C(:H)-Zr functional layer 400 can be formed using a physical vapor deposition method, preferably a physical vapor deposition method (PVD). , Physical Vapor Deposition) can be used.

The physical vapor deposition method can be formed using various methods such as arc ion plating (AIP, Arc Ion Plating), sputtering, and pulsed laser deposition (PLD) using a laser. In this embodiment, Arc ion plating using high-pressure arc discharge was used, but it is not limited to this, and a conventionally known physical vapor deposition method was used to form the bonding layer 200, the support layer 300, or the ta-C(:H)- A Zr functional layer 400 can be formed.

The bonding layer 200 is formed by applying an arc discharge to a target containing zirconium and depositing evaporated metal ions on the base material 100.

The bonding layer 200 may be formed to have a thickness of 0.01 ㎛ or more and 0.5 ㎛ or less, preferably 0.05 ㎛, but the present invention is not limited thereto.

When the thickness of the bonding layer 200 is formed to be less than 0.01㎛, the adhesion between the base material 100 and the support layer 300 decreases (HF hardness 2-3, bonding force 16N), thereby reducing durability, and the base material 100 The thickness of the coating material coated on the surface may be lost by more than 30%.

When the thickness of the bonding layer 200 is formed exceeding 0.5㎛, the coating time increases (exceeding 5 hours) and the hardness balance is lost within the coating material structure, thereby reducing durability and losing more than 25% of the thickness. there is.

The supporting layer 300 is formed by applying metal ions evaporated by applying an arc discharge to a target containing zirconium to play the role of supporting the ta-C(:H)-Zr functional layer 400, and injected with an active gas. Metal nitride particles formed by reacting nitrogen ions separated from nitrogen gas are deposited on the bonding layer 200.

The support layer 300 may be formed to have a thickness of 0.1 ㎛ or more and 5 ㎛ or less, preferably 0.2 ㎛, but the present invention is not limited thereto.

If the thickness of the support layer 300 is formed to be less than 0.1㎛, the hardness balance between layers in the coating material may be lost due to insufficient thickness, which may reduce durability (loss of more than 20% of the thickness) and cause local thickness loss or wear. It occurs frequently.

If the thickness of the support layer 300 exceeds 5㎛, the coating time increases and becomes excessively long, and as a brittle columnar structure is formed, the residual stress in the layer increases, causing the ta -C(:H)-Zr may have a negative effect (reduce durability) on the functional layer 400.

The ta-C(:H)-Zr functional layer 400 is formed by simultaneously applying an arc discharge to a target containing graphite and a target containing zirconium, so that evaporated carbon particles and zirconium particles are simultaneously deposited on the support layer 300. It is characterized by being formed by stacking.

The ta-C(:H)-Zr functional layer 400 contains more than 0 atomic% but less than 20 atomic% zirconium, and the remainder consists of carbon and inevitable impurities.

If the zirconium composition of the ta-C(:H)-Zr functional layer 400 exceeds 20 atomic%, there is a problem in that the strength is reduced due to excessive zirconium and expensive zirconium metal is unnecessarily used.

If the ta-C(:H)-Zr functional layer 400 consists only of carbon and inevitable impurities, wear occurs due to friction with external objects, and there is a problem of insufficient heat resistance at high temperatures generated by frictional heat.

In addition, the zirconium composition on the surface of the ta-C(:H)-Zr functional layer 400 satisfies 1 atomic% or more and 20 atomic% or less.

If the zirconium composition on the surface of the ta-C(:H)-Zr functional layer 400 is less than 1 atomic percent, the heat resistance of the functional layer becomes weak and may be damaged by high heat generated due to friction on the surface. .

The ta-C(:H)-Zr functional layer 400 is characterized by a composition gradient in which the zirconium composition continuously increases toward the surface.

In detail, the composition of zirconium in the ta-C(:H)-Zr functional layer 400 is tetragonal hydrogenated amorphous carbon (ta-C(:H)) (hereinafter referred to as 'hydrogenated amorphous carbon'). It is expressed as the atomic ratio of zirconium contained in the ta-C(:H)-Zr functional layer 400, assuming that the common conjugate of zirconium and zirconium is 100 atomic%.

Since the ta-C(:H)-Zr functional layer 400 has a minimum zirconium content at the interface where it is joined to the support layer 300, its bonding strength with the support layer 300 is improved to prevent damage from external impact. is prevented.

Conversely, the ta-C(:H)-Zr functional layer 400 has the maximum zirconium content on the outer surface, so wear resistance, heat resistance, and durability are improved, and the amount of wear is reduced during friction with external objects.

For example, the atomic ratio of hydrogenated amorphous carbon and zirconium in the ta-C(:H)-Zr functional layer 400 is changed from 100:0 to 90:10 in the surface direction, so that the support layer 300 and At the inner interface in contact, it is formed of hydrogenated amorphous carbon that does not contain zirconium, and the amount of zirconium contained in the hydrogenated amorphous carbon increases toward the outer surface, so that zirconium can be contained to a maximum on the outer side.

The compositional gradient in the ta-C(:H)-Zr functional layer 400 indicates that the zirconium content changes in any form, such as linear or curved, in a solid solution of zirconium in hydrogenated amorphous carbon.

For example, in a solid solution in which zirconium is dissolved in hydrogenated amorphous carbon, the content of zirconium increases or decreases in a straight line, curve, or alternately increases or decreases from the interface with the support layer 300 toward the outer surface in contact with the atmosphere. All cases can be referred to as having a compositional gradient formed.

Hereinafter, with reference to FIG. 4, a method of coating fuel injector parts according to a second embodiment of the present invention will be described step by step.

Referring to FIG. 4, the method of manufacturing fuel injector parts according to the second embodiment of the present invention involves reacting the base material 100 of the fuel injector part to deposit a multi-layered coating material on the surface of the base material 100. A step of mounting the base material inside the chamber (S10), a step of forming a bonding layer (S50) in which the bonding layer 200 is laminated on the outer peripheral surface of the base material 100, and a support layer 300 on the outer surface of the bonding layer 200. ) includes a support layer forming step (S60) in which the support layer 300 is laminated, and a functional layer forming step (S70) in which a ta-C(:H)-Zr functional layer 400 is laminated on the outer surface of the support layer 300.

First, in the base material mounting step (S10), the base material 100 is placed in the reaction chamber. At this time, the base material 100 can be mounted using a jig (not shown in the drawing). In detail, the base material 100 formed of a metal material can be fixed by applying an attractive force due to a magnetic field using a fixture equipped with a magnet.

In the bonding layer forming step (S50), the bonding layer 200 is formed by sputtering. That is, by injecting an inert gas in a vacuum and applying a negative voltage to the zirconium (Zr) target to discharge it, the ionized zirconium can form a thin film on the surface of the base material 100.

In this embodiment, a zirconium (Zr) target was used, but it can be formed using any one or more of titanium (Ti), tungsten (W), chromium (Cr), or molybdenum (Mo) targets.

In the support layer forming step (S60), metal nitride particles formed by reacting metal ions evaporated by applying an arc discharge to a target containing zirconium and nitrogen ions separated from nitrogen gas injected as an active gas are of the base material 100. It moves to the surface and forms a metal nitride layer.

In detail, in the support layer forming step (S60), when the lamination of the bonding layer 200 is completed, zirconium ions formed by sputtering as in the bonding layer forming step (S50) and nitrogen (N ₂ ) injected as an active gas ZrN particles may be formed by reacting N ions separated from the gas, and the support layer 300 may be formed by coating the ZrN particles on the outer surface of the bonding layer 200.

Meanwhile, in this embodiment and another embodiment, in the support layer forming step (S60), one or more metal ions of titanium (Ti), tungsten (W), chromium (Cr), or molybdenum (Mo) are reacted with N to form the support layer 300. ) is also possible to form.

Next, an arc discharge is simultaneously applied to the target containing graphite and the target containing zirconium so that the ta-C(:H)-Zr functional layer 400 is laminated on the outer surface of the support layer 300 to evaporate the target. A functional layer forming step (S70) in which carbon particles and zirconium particles are stacked on the support layer 300 to form a ta-C(:H)-Zr functional layer 400 may be performed.

In the functional layer forming step (S70), a target containing graphite and a target containing zirconium are subjected to thermal evaporation, arc evaporation, and stirrup using physical vapor deposition (PVD) such as FCVA (Filtered Cathodic Vacuum Arc). It can be deposited by terring.

FCVA (Filtered Cathodic Vacuum Arc) removes large particles generated by strong arc evaporation during coating through a magnetic filter, accelerates fine particles with improved uniformity and deposits them by colliding with the target object, resulting in a uniform high diameter surface. coating can also be implemented.

In the functional layer forming step (S70), the current applied to the target containing the graphite is continuously changed in the range of 60A to 100A, and the current applied to the target containing the zirconium is changed in the range of 80A to 110A. changes continuously.

For example, since the current applied to the target containing the graphite continuously decreases from 100A to 60A, and the current applied to the target containing zirconium increases from 80A to 110A, zirconium dissolved in hydrogenated amorphous carbon The composition can increase linearly compared to 100 atomic% hydrogenated amorphous carbon.

In this embodiment, the current applied to the target may be linearly increased or decreased, but the present invention is not limited to this, and the current applied to the target may be increased linearly in a curved manner or the current applied to the target linearly may be increased or decreased. It can be repeated.

If the current applied to the target containing graphite is less than 60A or the current applied to the target containing zirconium is less than 80A, arc evaporation does not sufficiently occur in the target and the ta-C(:H)-Zr functional layer (400 ) may not be formed uniformly.

In addition, when the current applied to the target containing graphite exceeds 100A or the current applied to the target containing zirconium exceeds 110A, arc evaporation occurs rapidly in the target, so ta-C(:H) The -Zr functional layer 400 may have an excessively thick thickness.

The functional layer forming step (S70) may be carried out under temperature conditions of 100 degrees Celsius or more and 400 degrees Celsius or less.

If the functional layer forming step (S70) is performed at less than 100 degrees Celsius, the adhesion between the base material 100 and the coating material may decrease, the process time may increase, and process productivity may decrease.

If the functional layer forming step (S70) is performed at a temperature exceeding 400 degrees Celsius, the power used to maintain the temperature increases, which acts as a factor in increasing maintenance costs and internal stress may increase or deformation may occur at high temperatures. .

In addition, the method of manufacturing fuel injector parts according to the second embodiment of the present invention includes, after the base material mounting step (S10), in a state where the base material 100 is placed inside the reaction chamber, A vacuum forming step (S20) of maintaining the internal atmosphere in a vacuum state, a plasma forming step (S30) of injecting Ar gas into the interior of the reaction chamber and raising the temperature of the chamber to form a plasma state in which Ar ions are generated, and It further includes a cleaning step (S40) of cleaning the surface of the base material 100 by colliding the Ar ions with the surface of the base material 100.

In the vacuum forming step (S20), the fixture on which the base material 100 is mounted is placed inside the reaction chamber, and the internal atmosphere of the reaction chamber can be formed and maintained in a vacuum state.

Next, in the plasma forming step (S30), Ar gas is supplied as a process gas, and the temperature is raised using a thermostat to form a plasma state in which Ar ions are formed.

Afterwards, in the cleaning step (S40), a bias voltage is applied to the bias electrode and Ar ions are accelerated to collide with the surface of the base material 100, thereby cleaning the surface of the base material 100.

This is to increase the adhesion between the coating material and the base material 100 by preferentially performing an etching process to remove the oxide layer and impurities naturally formed on the surface of the base material 100.

Also, in this case, the bias voltage can be maintained in the range of 200 to 400V. If the bias voltage is less than 200V, the acceleration voltage of Ar ions decreases, lowering the hardness of the coating material, and if the bias voltage exceeds 400V, the lattice arrangement becomes irregular, which may cause a problem of reduced adhesion.

Hereinafter, the results of durability evaluation and physical property evaluation will be described for an example manufactured by applying the coating method for fuel injector parts according to the present invention and a comparative example manufactured according to the prior art.

Example

First, a spherical base material 100 is placed, a plasma state is created using Ar gas while the inside of the chamber is vacuum, and the inside of the chamber is heated to 80° C. to form a base material 100 made of SUS440C stainless steel. After activating the surface, the surface of the base material 100 was cleaned by applying a bias voltage of 300V so that Ar ions collide with the surface.

Afterwards, the bonding layer 200 containing Zr was laminated to a thickness of 0.05 ㎛ on the surface of the base material 100 using Zr ions evaporated through a PVD method.

Then, N ₂ , a process gas, was injected into the chamber and reacted with Zr ions evaporated from the Zr target to coat the support layer 300 of ZrN to a thickness of 0.2 μm.

Thereafter, the target material containing carbon and the target material containing zirconium are deposited by arc evaporation, and at the same time, hydrocarbon gas and Ar gas are injected into the reaction chamber to form the ta-C(:H)-Zr functional layer ( 400) was formed.

The current applied to the target material containing carbon decreases with time, and the current applied to the target material containing zirconium increases with time, so that hydrogenated amorphous carbon and hydrogenated amorphous carbon are formed at the junction interface with the support layer 300. The atomic ratio of zirconium is formed at 100:0, and a gradient structure in which zirconium increases in the surface direction is formed, so that hydrogenated amorphous carbon and zirconium are formed on the surface of the ta-C(:H)-Zr functional layer 400. The atomic ratio is 90:10.

Comparative Example 1

Unlike the embodiment according to the present invention, the current applied to the target material containing carbon and the target material containing zirconium in the base material 100 is maintained constant, thereby forming the ta-C(:H)-Zr functional layer 400. The atomic ratio of hydrogenated amorphous carbon and zirconium is formed at 90:10 throughout the entire thickness direction.

Except for this, the base material 100, the bonding layer 200, and the support layer 300 are configured in the same manner as in the embodiment.

Comparative Example 2

Unlike the embodiment according to the present invention, a coating material is not formed on the base material 100. The base material 100 is made of SUS440C stainless steel, as in the embodiment.

Durability performance evaluation experiment

To evaluate durability performance, a dry-run test was conducted. The durability test was an experiment to evaluate the durability of each coating material in a short period of time, and was conducted under the following test conditions for Examples and Comparative Examples 1 to 2.

The test gas is air or nitrogen, the supply pressure is 5 bar, the test temperature is at room temperature, PHID (Peak&Hold, 1.2A&0.6A current control method) is used as the driver stage, the supply voltage is 14.0V, and the pulse interval is 14.0V. (period) is 5.0ms, pulse width (width) is 2.5ms, and the operating time is more than 30 minutes.

As a criterion, it was visually confirmed whether there was any damage such as peeling of the surface of the coating material, and the coating thickness was evaluated.

The coating thickness was measured by measuring the average value at 0° and 180° of the product and the thickness deviation of the coating material at the two locations. Thickness was measured using a calo tester.

Physical property evaluation

In order to evaluate the physical properties of the coating material, a physical property evaluation was conducted.

To derive the friction coefficient, a plate on disk experiment was conducted using 10N, 0.1m/s, 2km, and SUS440C pin.

A micro indenter (0.05N, 0.7㎛ indenting depth) was used to measure hardness.

A scratch tester and a Rockwell C tester (HF1: high bonding force, HF5: low bonding force) were used to measure bonding force.

division Example Comparative Example 1 Comparative Example 2 Zr/ ZrN/ta-C(:H)-Zr
gradient Zr/ ZrN/ta-C(:H)-Zr SUS440C (no coating) Hardness (HV) 5042
(49.5 GPa) 4138
(40.6 GPa) 769
(7.3 GPa) Heat resistance temperature 700℃ 700℃ - Illuminance Ra (um) 0.017 0.025 0.2 Friction coefficient dry 0.03 0.07 0.43 friction coefficient oil 0.019 0.04 0.20 Thickness (um) 1.0 1.0 - Adhesion HF 1
45N HF 1
35N - coating time < 4h <6h - coating process FCVA & PACVD PVD & PACVD - Durability evaluation results
(Dry-run test) Thickness: 0% loss
Visually: No wear marks Thickness: 5% loss
Visually: small wear marks Large wear marks

According to Table 1, as a result of the durability performance test, it was confirmed that the fuel injector parts according to the embodiment of the present invention lost 0% of the thickness of the coating material and no wear marks were found.

On the other hand, in the case of Comparative Example 1, it was confirmed that the thickness of the coating material was lost by 5% and some wear marks were found.

In addition, in the case of Comparative Example 2, many wear marks were found, confirming that it was significantly worn during the durability performance process.

As a result, as a result of testing the durability performance of fuel injector parts, it was confirmed that the embodiment of the present invention had a very low loss rate of the coating material compared to the comparative examples and had very excellent durability performance.

In addition, the hardness value of the Example of the present invention was superior to that of the Comparative Examples, and the coefficient of friction was measured to be relatively low, confirming that the frictional resistance was reduced.

In addition, the adhesion of the coating material according to the embodiment of the present invention is 45N, which is evaluated to be superior to the adhesion of 35N in other comparative examples, especially Comparative Example 1, which is the ta-C(:H)-Zr functional layer of the present invention ( Since 400) is formed in a gradient structure, it is analyzed that the bonding strength with the support layer is improved.

Although the present invention has been described in detail through specific examples, this is for detailed explanation of the present invention, and the present invention is not limited thereto, and the present invention is intended to be understood by those skilled in the art within the technical spirit of the present invention. It is clear that modifications and improvements are possible.

All simple modifications or changes of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be made clear by the appended claims.

A: ball
B: Needle
C: valve seat
100: Base material
200: bonding layer
300: support layer
400: ta-C(:H)-Zr functional layer

Claims (13)

Base material;
A bonding layer laminated on the surface of the base material;
A support layer laminated on the outer surface of the bonding layer; and
A ta-C(:H)-Zr functional layer laminated on the outer surface of the support layer;
Including,
The ta-C(:H)-Zr functional layer is,
A compositional gradient of zirconium is formed toward the surface,
The ta-C(:H)-Zr functional layer is,
A composition gradient is formed in which the composition of zirconium continuously increases toward the surface,
The ta-C(:H)-Zr functional layer is,
Parts for fuel injectors containing 1 atomic% or more and 20 atomic% or less zirconium.
In claim 1,
The bonding layer is,
A fuel injector component formed by applying an arc discharge to a target containing zirconium and depositing evaporated metal ions on the base material.
In claim 1,
The support layer is,
A fuel injector component formed by depositing metal nitride particles formed by reacting metal ions evaporated by applying an arc discharge to a target containing zirconium and nitrogen ions separated from nitrogen gas injected as an active gas, and depositing them on the bonding layer. .
In claim 1,
The ta-C(:H)-Zr functional layer is,
A part for a fuel injector, wherein an arc discharge is simultaneously applied to a target containing graphite and a target containing zirconium, and evaporated carbon particles and zirconium particles are stacked on the support layer.
In claim 1,
The ta-C(:H)-Zr functional layer is,
Parts for fuel injectors, characterized in that they contain more than 0 atomic% but not more than 30 atomic% hydrogen, and the balance consists of carbon and inevitable impurities.
delete A coating method of laminating a multi-layered coating material on the surface of the base material of fuel injector parts,
A base material mounting step of placing the base material inside the reaction chamber;
A bonding layer forming step of stacking a bonding layer on the outer peripheral surface of the base material;
A support layer forming step of laminating a support layer on the outer surface of the bonding layer; and
A functional layer forming step of laminating a ta-C(:H)-Zr functional layer on the outer surface of the support layer;
Including,
The functional layer forming step is,
By simultaneously applying an arc discharge to a target containing graphite and a target containing zirconium, evaporated carbon particles and zirconium particles are stacked on the support layer to form a ta-C(:H)-Zr functional layer;
The functional layer forming step is,
The current applied to the target containing zirconium is continuously applied in the range of 80A to 110A so that the ta-C(:H)-Zr functional layer forms a composition gradient in which the composition of zirconium continuously increases in the direction of the surface portion. Changing coating methods for fuel injector components.
In claim 7,
The bonding layer forming step is,
A coating method for fuel injector parts, characterized in that metal ions evaporated by applying an arc discharge to a target containing zirconium move to the surface of the base material to form a metal layer.
delete In claim 7,
The support layer forming step is,
Metal nitride particles formed by reacting metal ions evaporated by applying an arc discharge to a target containing zirconium and nitrogen ions separated from nitrogen gas injected as an activation gas move to the surface of the base material to form a metal nitride layer. Coating method for fuel injector parts.
delete In claim 7,
The functional layer forming step is,
A coating method for fuel injector parts, characterized in that the current applied to the target containing the graphite is continuously changed in the range of 60A or more and 100A or less.
In claim 7,
After the base material mounting step, a vacuum forming step of maintaining the internal atmosphere of the reaction chamber in a vacuum state while the base material is placed inside the reaction chamber;
A plasma forming step of injecting Ar gas into the reaction chamber and raising the temperature of the reaction chamber to form a plasma state in which Ar ions are generated; and
A cleaning step of colliding the Ar ions with the surface of the base material to clean the surface of the base material;
A coating method for parts for fuel injectors, further comprising:

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