Coated member and method for manufacturing coated member

Abstract

To provide a coating member having a coating layer composed of BN on a metal base material containing Fe, in which the adhesion of the coating layer is secured and the reduction of the film deposition rate of the coating layer is suppressed.SOLUTION: The coated member 1 is provided with a metallic base material 10 containing Fe, an intermediate layer 20 containing Al, B, O and N, and a coating layer 30 composed of BN, and the intermediate layer 20 and the coating layer 30 are laminated on the metallic base material 10 in this order. The coated member 1 is manufactured by forming the intermediate layer 20 and the coating layer 30 on the surface of the metal base material 10 by an atomic layer deposition method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a coated member in which a coating layer is formed on a metal substrate, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, there have been known coated members configured such that a coating layer is formed on the surface of a metal substrate to obtain desired properties such as wear resistance, low friction, corrosion resistance, and water resistance, and methods for manufacturing such members. An example of this type of coated member is described in Patent Document 1. The coated member described in Patent Document 1 is configured by laminating, in this order, a compound layer made of at least one of nitrides, carbides, and oxides of the constituent elements of the metal substrate on a metal substrate containing Fe (iron), and a ceramic coating layer. For example, when the coating layer is made of BN (boron nitride), the compound layer is interposed between the metal substrate and the coating layer, thereby ensuring adhesion of the coating layer and improving wear resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 62-103368 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, coating layers for this type of coating component have been formed using atomic layer deposition (ALD), which can form uniform, low-defect films not only on flat surfaces but also on uneven surfaces with high aspect ratios.

[0005] As a result of investigations by the present inventors, it was newly discovered that in a coating member in which a coating layer made of BN is formed on a metal substrate containing Fe, the deposition rate of the coating layer decreases.

[0006] In view of the above, an object of the present disclosure is to provide a coating member having a coating layer made of BN on a metal substrate containing Fe, and having a structure that can suppress a decrease in the film formation rate of the coating layer while ensuring adhesion of the coating layer, and a method for manufacturing the same. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a coating member comprises a metal substrate (10) containing Fe, an intermediate layer (20) formed on the surface of the metal substrate and containing Al, B, O, and N, and a coating layer (30) formed on the surface of the intermediate layer and made of BN.

[0008] This coating member has a structure in which an intermediate layer containing Al, B, O, and N serves as a base when a coating layer made of BN is formed on a metal substrate containing Fe, and the intermediate layer functions as a barrier layer during the formation of the coating layer. In other words, the coating member has a structure in which the intermediate layer acts as a barrier layer that prevents Fe from being mixed in from the metal substrate during the formation of the coating layer, thereby suppressing a decrease in the deposition rate of the coating layer. Furthermore, because the coating layer of the coating member is BN and contains B and N, adhesion between these elements is ensured. Therefore, the coating member has a coating layer made of BN on a metal substrate containing Fe, and while ensuring adhesion of the coating layer, a decrease in the deposition rate of the coating layer is suppressed.

[0009] According to another aspect of the present disclosure, a method for producing a coating member includes forming, by atomic layer deposition, on a surface of a metal substrate (10) containing Fe, an intermediate layer (20) containing Al, B, O, and N, and a coating layer (30) made of BN on the surface of the intermediate layer.

[0010] This method for producing a coating member involves depositing an intermediate layer containing Al, B, O, and N, and a coating layer made of BN, in that order, on a metal substrate containing Fe by ALD. This provides the base of the coating layer with an intermediate layer containing Al, B, O, and N, which functions as a barrier layer that inhibits the intrusion of Fe from the metal substrate and prevents a decrease in the coating layer deposition rate. Furthermore, by forming the intermediate layer containing B and N, this method can ensure the adhesion of the coating layer formed thereon. Therefore, this method makes it possible to produce a coating member having a BN coating layer on a metal substrate containing Fe, ensuring the adhesion of the coating layer, while preventing a decrease in the coating layer deposition rate.

[0011] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view showing a coating member according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the results of observation of a cross section of a coating member of a comparative example using a transmission electron microscope (TEM). [Figure 3] FIG. 10 is a diagram showing the results of comparison of the film formation rates of the coating layer on a silicon substrate, a comparative example, and an example. [Figure 4] FIG. 1 is a diagram showing the results of TEM observation of a cross section of a coating member of an example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals.

[0014] (Embodiment) A coating member 1 according to an embodiment will be described.

[0015] 1, the coating member 1 of this embodiment comprises a metal substrate 10 containing Fe, an intermediate layer 20 formed on the surface of the metal substrate 10, and a coating layer 30 formed on the surface of the intermediate layer 20. The coating member 1 is based on a substrate containing Fe and is suitable for application to various components that require desired properties such as wear resistance, such as injectors, nozzle bodies, bearings, and sliding parts, but is not limited to these components.

[0016] The metal substrate 10 is a substrate made of a metal material containing iron, such as pure iron or an iron alloy. The metal substrate 10 has a configuration in which the portion on which the coating layer 30 is formed contains Fe, and may be a single member made of the above metal material, or a composite member including a member made of a metal material other than the above metal material. The shape, size, etc. of the metal substrate 10 are arbitrary and can be changed as appropriate depending on the application of the coating member 1. At least a portion of the surface of the metal substrate 10 is covered with an intermediate layer 20.

[0017] The intermediate layer 20 is a mixed layer containing aluminum (Al), boron (B), oxygen (O), and nitrogen (N). The intermediate layer 20 is provided to ensure adhesion of the coating layer 30 and prevent a decrease in the deposition rate of the coating layer 30. Specifically, the intermediate layer 20 contains B and N, serving as a base to ensure adhesion with the BN coating layer 30 and also functions as a barrier layer to prevent the intrusion of Fe from the metal substrate 10 during deposition of the coating layer 30. The intermediate layer 20 does not contain Fe, and serves as a barrier layer during deposition of the coating layer 30. This prevents the intrusion of Fe from the metal substrate 10 and thereby prevents a decrease in the deposition rate of the coating layer 30. The intermediate layer 20 is deposited by ALD and has a thickness of, for example, 15 nm or more. The intermediate layer 20 may cover a portion or the entire surface of the metal substrate 10, and this thickness is appropriately adjusted depending on the application of the coating member 1. The deposition of the intermediate layer 20 will be described later.

[0018] The coating layer 30 is a film made of BN, and improves properties such as wear resistance, low friction, corrosion resistance, and water resistance. The coating layer 30 is formed by ALD, and has a film thickness sufficient to provide wear resistance (not limited to, but greater than 10 nm). The coating layer 30 is formed on the intermediate layer 20, and may cover a portion of the intermediate layer 20 or the entire intermediate layer 20, and similarly to the intermediate layer 20, the thickness is appropriately changed depending on the application of the coating member 1, etc. The formation of the coating layer 30 will be described later.

[0019] The above is the basic configuration of the coating member 1. The coating member 1 has a structure in which the intermediate layer 20 and the coating layer 30 are laminated in this order on at least a portion of the surface of the metal substrate 10, thereby ensuring the adhesion of the coating layer 30 and suppressing a decrease in the deposition rate of the coating layer 30.

[0020] Next, a method for manufacturing the coating member 1 will be described.

[0021] A metal substrate 10 having a desired size and shape is prepared and set in a reactor of an ALD film formation apparatus (not shown). Before setting the metal substrate 10 in the ALD film formation apparatus, known pretreatments such as cleaning, degreasing, and reduction treatment may be performed on the metal substrate 10, as needed.

[0022] First, the intermediate layer 20 is formed by the ALD process. In the ALD process of the intermediate layer 20, a reactor containing the metal substrate 10 is placed in a reduced pressure environment, and the Al, B, O, and N raw materials constituting the intermediate layer 20 are separately supplied to the surface of the metal substrate 10 via carrier gases. For example, trimethylaluminum (TMA), i.e., Al(CH3)3, can be used as the Al raw material. For example, tris(dimethylamino)borane (TDMAB), i.e., B[N(CH3)2]3 can be used as the B raw material. For example, O2 plasma can be used as the O raw material. For example, NH3 plasma can be used as the N raw material. For example, an inert gas such as N2 can be used as the carrier gas.

[0023] In the ALD process for the intermediate layer 20, a first step is first performed, in which a B source gas and an N source gas are alternately supplied via a purge and reacted on the metal substrate 10, and the first step is repeated multiple times. Specifically, for example, in the first step, the B source gas is supplied via a carrier gas, adsorbed onto the metal substrate 10, the supply of the B source gas is stopped, and the gas in the reactor is purged. Next, the N source gas is supplied via a carrier gas, reacted on the metal substrate 10, the supply of the N source gas is stopped, and the gas in the reactor is purged. In the first step, a series of steps from the supply and adsorption of the B source gas, to the purging of the B source gas, the supply and reaction of the N source gas, and the purging of the N source gas are repeated, for example, several hundred times.

[0024] In the ALD process for the intermediate layer 20, after the first step, a second step is performed in which an Al source gas and an O source gas are alternately supplied via a purge and reacted on the metal substrate 10. This second step is repeated multiple times. Specifically, in the second step, an Al source gas is first supplied via a carrier gas and adsorbed onto the metal substrate 10, after which the supply of the Al source gas is stopped and the gas in the reactor is purged. Next, an O source gas is supplied via a carrier gas and reacted on the metal substrate 10, after which the supply of the O source gas is stopped and the gas in the reactor is purged. In the second step, a series of steps, from the supply and adsorption of the Al source gas to the purging of the Al source gas, the supply and reaction of the O source gas, and the purging of the O source gas, are repeated, for example, several tens of times.

[0025] The ALD process for the intermediate layer 20 then includes a third process in which the first and second processes are alternately performed multiple times, for example, several times. By performing these first, second, and third processes, a mixed layer containing Al, B, O, and N (hereinafter, for convenience, referred to as an "AlBON mixed layer") can be formed as the intermediate layer 20. In the ALD process for the intermediate layer 20, it is preferable to form an AlBON mixed layer with a thickness of at least 15 nm so that the intermediate layer 20 functions as a barrier layer that prevents Fe from the metal substrate 10 in the subsequent coating layer 30 deposition process.

[0026] The term "AlBON mixed layer" means that the intermediate layer 20 is a layer in which Al, B, O, and N are mixed, and is not limited to a composition ratio of Al, B, O, and N of 1:1:1:1. The ALD process for the intermediate layer 20 is performed, for example, by controlling the temperature of the metal substrate 10 to a constant temperature in the range of several tens of degrees Celsius to approximately 300 degrees Celsius using a heating mechanism (not shown). This also applies to the ALD process for the subsequent coating layer 30.

[0027] Next, the coating layer 30 is formed by an ALD process. The ALD process for the coating layer 30 is, for example, similar to the first step in the ALD film formation of the intermediate layer 20 described above, in which a series of steps of supplying and adsorbing a B source gas, purging, supplying and reacting an N source gas, and purging are repeated several hundred times. This allows, for example, the coating layer 30 made of BN to be formed on the intermediate layer 20 with a thickness of several 10 nm to several tens of nm.

[0028] The above is the basic method for manufacturing the coating member 1. By forming the intermediate layer 20 made of an AlBON mixed layer that does not contain Fe as a base for the coating layer 30 made of a BN film, it is possible to ensure the adhesion of the coating layer 30 and prevent a decrease in the film formation rate.

[0029] Next, the suppression of a decrease in the film formation rate of the coating layer 30 by the intermediate layer 20 will be described.

[0030] The inventors prepared a comparative coating member by forming a coating layer made of BN by an ALD process on a sample of a metal substrate containing Fe, which had a substrate-altered layer formed on the surface of the metal substrate by altering the metal substrate. When this comparative coating member was observed using a transmission electron microscope (TEM), it was found that the substrate-altered layer and the coating layer were deposited in this order on the metal substrate, as shown in Figure 2. The TEM image shown in Figure 2 shows the metal substrate as the brightest (i.e., nearly white), the coating layer as the darkest (i.e., nearly black), and the substrate-altered layer as an intermediate brightness.

[0031] The composition of the region of the substrate alteration layer indicated by the square frame in Figure 2 was evaluated by energy dispersive spectroscopy (EDX), and was found to be 50 atm% Fe, 32 atm% O, and 9 atm% N, making it a mixed layer of Fe, O, and N. Similarly, the composition of the coating layer was evaluated, and approximately 4 atm% Fe was detected in the coating layer, indicating that it was a mixed layer containing Fe in addition to B and N.

[0032] Furthermore, TEM images of the comparative coating member showed that the substrate-altered layer had a thickness of approximately 13 nm and the coating layer had a thickness of approximately 6 nm. The boundaries between the metal substrate, the substrate-altered layer, and the coating layer can be determined, for example, by elemental mapping of TEM images using EDX. Here, one cycle in the ALD process for the coating layer, consisting of the supply and adsorption of the B source gas, purging, the supply and reaction of the N source gas, and purging, is considered to be one cycle, and the number of repetitions is the number of cycles. The film formation rate per cycle (nm / cycle), calculated by dividing the thickness of the coating layer by the number of cycles, was approximately 0.0017, as shown in Figure 3.

[0033] Additionally, a sample was prepared in which a BN film was formed by the ALD process on a Si (silicon) substrate that did not contain Fe, and the deposition rate (nm / cycle) of the BN film was calculated to be approximately 0.0065, as shown in Figure 3. The reason for the lower BN deposition rate in the comparative coating member compared to the Si substrate is thought to be that Fe from the metal substrate was mixed into the BN film.

[0034] In addition, a coating member 1 (hereinafter referred to as "Example coating member 1") was fabricated by laminating an intermediate layer 20 and a coating layer 30 on an Fe-containing metal substrate 10 using the ALD process described above, and the Example coating member 1 was subjected to TEM observation. As a result, as shown in FIG. 4, the Example coating member 1 had a layered intermediate layer 20 and coating layer 30 deposited on the metal substrate 10, with the intermediate layer 20 being approximately 15 nm thick and the coating layer 30 being approximately 22 nm thick. The TEM image shown in FIG. 4 shows the metal substrate 10 as the brightest, the coating layer 30 as the darkest, and the intermediate layer 20 as an intermediate brightness. The boundaries between the metal substrate 10, intermediate layer 20, and coating layer 30 in the TEM image can be determined, for example, by elemental mapping of the TEM image using EDX.

[0035] Furthermore, when the compositions of the intermediate layer 20 and the coating layer 30 of the coating member 1 of the example were evaluated by EDX, no Fe was detected. This is believed to be due to the intermediate layer 20, which was composed of an approximately 15 nm thick AlBON mixed layer, functioning as a barrier layer to suppress the incorporation of Fe from the metal substrate 10. Furthermore, when the BN deposition rate for the coating layer 30 was calculated in the same manner as above, as shown in Figure 3, the deposition rate was approximately 0.0062 nm / cycle, which is comparable to that of a BN film on a Si substrate and significantly improved compared to the coating member of the comparative example. This result suggests that when forming a BN coating layer 30 on a metal substrate 10 containing Fe, using the intermediate layer 20, which functions as a barrier layer to block Fe, as a base, can suppress a decrease in the deposition rate during the BN ALD process.

[0036] According to this embodiment, an intermediate layer 20 containing Al, B, O, and N, and a coating layer 30 made of BN are laminated in this order on a metal substrate 10 containing Fe, resulting in a coating member 1 having a structure that suppresses a decrease in the film formation rate in the ALD process of the coating layer 30. Furthermore, since the intermediate layer 20 contains B and N, the coating member 1 has a structure that can ensure the adhesion of the coating layer 30 and suppress a decrease in the film formation rate at the same time.

[0037] The method for producing the coating member 1 of this embodiment involves laminating, in this order, an intermediate layer 20 containing Al, B, O, and N and a coating layer 30 made of BN by ALD on the surface of a metal substrate 10 containing Fe. This makes it possible to produce a coating member 1 having a structure that ensures the adhesion of the coating layer 30 while suppressing a decrease in the film formation rate.

[0038] (Other embodiments) Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and modifications within the scope of equivalents. In addition, various combinations and forms, as well as other combinations and forms including only one element, more than one, or less than one, are also within the scope and spirit of the present disclosure.

[0039] It goes without saying that in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shapes, positional relationships, etc. of the components are mentioned, they are not limited to the shapes, positional relationships, etc., unless they are specifically stated or are clearly limited to a specific shape, positional relationship, etc. in principle. [Explanation of symbols]

[0040] 10 Metal substrate 20 Middle Class 30 coating layers

Claims

1. A metal substrate (10) containing Fe; an intermediate layer (20) formed on the surface of the metal substrate and containing Al, B, O and N; a coating layer (30) formed on the surface of the intermediate layer and made of BN.

2. The coating member according to claim 1 , wherein the intermediate layer does not contain Fe.

3. The coating member according to claim 1 or 2, wherein the intermediate layer has a thickness of 15 nm or more.

4. A method for producing a coating member, comprising forming an intermediate layer (20) containing Al, B, O, and N on the surface of a metal substrate (10) containing Fe, and forming a coating layer (30) made of BN on the surface of the intermediate layer by atomic layer deposition.

5. 5. The method for producing a coating member according to claim 4, wherein in forming the intermediate layer, an Al source, a B source, an O source, and an N source are separately supplied via a carrier gas to form a mixed layer of Al, B, O, and N.

6. 6. The method for manufacturing a coating member according to claim 5, wherein the intermediate layer is formed by a first step of alternately supplying the B raw material and the N raw material multiple times via purging to form a film, a second step of alternately supplying the Al raw material and the O raw material multiple times via purging to form a film, and a third step of alternately repeating the first step and the second step multiple times.

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