Surface-coated tool, particularly surface-coated forming tap, and manufacturing method thereof

Abstract

To provide a surface-coated tool which is excellent in abrasion resistance and adhesion resistance, particularly, a surface-coated cold forming tap.SOLUTION: A method for manufacturing a surface-coated tool that includes a base material and a I layer and a II layer coated in this order on the surface of the base material, in which the I layer and the II layer are each independently at least one of a titanium nitride film, a titanium carbide film, and a titanium carbonitride film, includes the following steps (1) to (3): (1) forming the I layer by an arc ion plating method; (2) subjecting the I layer to ion bombardment treatment using metal ions; and (3) forming the II layer on the I layer after the ion bombardment treatment by a sputtering method.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a surface-coated tool, in particular a surface-coated forming tap, and a method for manufacturing the same. [Background technology]

[0002] Rolling tools and cutting tools are known as tools for processing metals, etc. Rolling is a processing method (also known as "plastic processing") in which a material is shaped by applying a strong force to it. Cutting is a processing method in which a material is shaped by cutting it.

[0003] When a rolling tool such as a forming tap is used to form a female thread in a workpiece, the forming part (also referred to as the "thread part") formed in a helical shape of the forming tap is generally rotated relative to the workpiece in which a pilot hole has been drilled with a drill or the like, and the formed part is gradually driven into the pilot hole in the workpiece while being rotated, thereby plastically deforming the pilot hole portion.

[0004] However, when the threads of the threading tap begin to plastically deform the pilot hole in the workpiece, deformation resistance occurs, which applies high pressure to the crest portion (also referred to as the "outside diameter") and flank surface of the threads of the threading tap. As a result, heat is generated due to intense friction between the threading tap and the workpiece, and heat is generated due to plastic deformation of the workpiece, which can cause the threading tap and the workpiece to become very hot. Meanwhile, the surface of the pilot hole in the workpiece is strongly pressed by the threads of the threading tap, causing its metallographic structure to elongate, which can lead to the metallographic structure peeling off from the surface. The peeled metallographic structure can then adhere to the outside diameter and flank surface of the threads of the threading tap due to the high pressure at the contact surface with the threading tap and the high temperatures of the threading tap and the workpiece.

[0005] In order to prevent the above problems, the forming tap is subjected to a surface treatment with a hard coating to impart wear resistance and adhesion resistance (i.e., a smoother surface state) to the forming tap.

[0006] In recent years, numerous developments have been made with regard to the surface treatment of rolling or cutting tools.

[0007] For example, Patent Document 1 discloses a hard-coated tool whose surface is coated with a hard coating. More specifically, the tool in Patent Document 1 has an I layer made of a nitride or carbonitride of AlA1aTibCrc (where a, b, and c are atomic ratios, 0.3≦a≦0.7, 0≦b≦0.5, 0≦c≦0.7, and a+b+c=1), and a II layer that is a composite film in which a nitride phase made of CrAlN and a BN phase are three-dimensionally mixed. The I layer is provided on the surface of a tool substrate, and the I layer and the II layer are alternately stacked in four or more layers to form the hard coating. The thickness of the I layer provided on the surface of the tool substrate is within a range of 10 nm to 500 nm, and the thicknesses of the other I and II layers are all within a range of 1 nm to 50 nm, and the total thickness of the entire coating is within a range of 0.1 μm to 20 μm.

[0008] Patent Document 2 also discloses a cutting tool including a body and a multilayer coating applied to the body. More specifically, the tool of Patent Document 2 has a first layer A of a hard material selected from titanium aluminum nitride (TiAlN), titanium aluminum silicon nitride (TiAlSiN), chromium nitride (CrN), aluminum chromium nitride (AlCrN), aluminum chromium silicon nitride (AlCrSiN), and zirconium nitride (ZrN) applied to the body, and a second layer B of silicon nitride (Si3N4) applied directly on the first layer A.

[0009] Patent Document 3 discloses a surface-coated tool that has excellent adhesion between the substrate and the coating and can withstand severe cutting conditions. More specifically, the tool in Patent Document 3 includes a substrate and a coating formed on the substrate, the substrate including WC particles and a binder phase containing Co that bonds the WC particles together, the coating including an adhesion layer in contact with the substrate and an upper layer formed on the adhesion layer, the adhesion layer having a thickness of 0.5 nm to 20 nm, and the adhesion layer containing carbides, nitrides, or carbonitrides including one or more elements selected from Cr, Ti, Zr, and Nb, one or more elements selected from the elements constituting the substrate, and one or more elements selected from the elements constituting the upper layer. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-052478 [Patent Document 2] International Publication No. 2012 / 016954 [Patent Document 3] Japanese Patent Application Publication No. 2019-069514 Summary of the Invention [Problem to be solved by the invention]

[0011] For forming the coating on the tool, methods such as sputtering and arc ion plating are used.

[0012] Although it is known that a coating formed by a sputtering method can have a smooth surface, the ionization rate is lower than that of a coating formed by an arc ion plating method, and therefore the density is low. Therefore, when a coating formed by a sputtering method is used for surface treatment, there is a problem that sufficient wear resistance cannot be obtained, particularly for rolling tools such as forming taps, which are considered to be subjected to a high processing load.

[0013] On the other hand, although the coating formed by the arc ion plating method has a high ionization rate, it is prone to producing molten particles (also called "droplets") that are submicron to several micron in size. Therefore, when using a coating formed by the arc ion plating method for surface treatment, it is difficult to obtain a smooth surface, that is, there is a problem that sufficient adhesion resistance cannot be obtained.

[0014] The present invention is intended to improve the above-mentioned circumstances, and an object thereof is to provide a surface-coated tool, particularly a surface-coated forming tap, which has excellent wear resistance and adhesion resistance, and a method for manufacturing the same. [Means for solving the problem]

[0015] The present invention that achieves the above object is as follows.

[0016] <Aspect 1> A method for manufacturing a surface-coated tool, comprising the steps of: the tool includes a substrate and a layer I and a layer II coated in this order on a surface of the substrate; the layer I and the layer II are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and A method comprising the following steps (1) to (3): (1) forming the layer I on the substrate by an arc ion plating method; (2) subjecting the I layer to an ion bombardment treatment using metal ions; and (3) Forming a second layer by sputtering on the first layer after the ion bombardment treatment. <Aspect 2> The method according to aspect 1, wherein a relationship between an arithmetic mean roughness Ra0 of the surface of the base material and an arithmetic mean roughness Ra2 of the surface of the II layer satisfies the following formula (1): 0μm≦Ra2-Ra0<0.060μm (1) <Aspect 3> 3. The method of claim 1, wherein the arithmetic mean roughness Ra of the surface of the layer II is 0.150 μm or less. <Aspect 4> Aspect 4. The method according to any one of aspects 1 to 3, wherein in step (2), the metal ion is a Cr ion. <Aspect 5> Aspect 5. The method of any one of aspects 1 to 4, wherein the tool is a forming tap. <Aspect 6> A substrate, and a layer I and a layer II coated in this order on a surface of the substrate, the I layer is an arc ion plating layer, the layer II is a sputtering layer, the layer I and the layer II are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and the relationship between the arithmetic mean roughness Ra0 of the surface of the base material and the arithmetic mean roughness Ra2 of the surface of the II layer satisfies the following formula (1): Surface coated tools: 0μm≦Ra2-Ra0<0.060μm (1) <Aspect 7> 7. The tool of claim 6, wherein the layer II has a surface with an arithmetic mean roughness Ra of 0.150 μm or less. <Aspect 8> The thickness of the layer I is 1.0 μm or more and 5.0 μm or less, and The thickness of the layer II is 1.0 μm or less. 8. The tool of claim 6 or 7. <Aspect 9> The tool according to any one of aspects 6 to 8, wherein the surface roughness in maximum height Rz of the layer II is 1,300 μm or less. <Aspect 10> 10. The tool of any one of aspects 6 to 9, wherein the layer I is made up of two or more coatings. <Aspect 11> A tool according to any one of aspects 6 to 10, wherein the Cr content in the surface of the layer I is less than 1.0 at %. <Aspect 12> 12. The tool according to claim 6, wherein the tool is a forming tap. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a surface-coated tool that is excellent in wear resistance and adhesion resistance. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the surface-coated tool of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing an example of the configuration of the surface-coated tool of the present invention. [Figure 3] FIG. 3 is a flow chart showing an outline of the steps involved in the manufacturing method of the present invention. [Figure 4] FIG. 4 is a side perspective view schematically showing an example of a film forming apparatus used in the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view showing the configuration of the test tap and test piece of Example 1. [Figure 6] Figure 6(a) is a surface photograph of the test tap of Example 1, Figure 6(b) is a surface photograph of the test tap of Comparative Example 1, Figure 6(c) is a surface photograph of the test tap of Comparative Example 2, and Figure 6(d) is a surface photograph of the test tap of Comparative Example 3. [Figure 7] Fig. 7 shows the observation results of the indented area of ​​Example 1. Fig. 7(b) is an enlarged view of the area enclosed by the square frame in Fig. 7(a). [Figure 8] Fig. 8 shows the observation results of the indented area of ​​Comparative Example 1. Fig. 8(b) is an enlarged view of the area enclosed by the square frame in Fig. 8(a). [Figure 9] FIG. 9 is a diagram showing the observation results of the indented portion of Comparative Example 2. [Figure 10] FIG. 10 is a photograph of the test tap of Example 1 after drilling 1,600 holes. [Figure 11] FIG. 11 is a photograph of the test tap of Comparative Example 3 after drilling 1,600 holes. [Figure 12]FIG. 12 is a photograph of the test tap of Example 1 after 880 holes were drilled. [Figure 13] FIG. 13 is a photograph of the test tap of Comparative Example 3 after drilling 880 holes. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. For the sake of convenience, the same or corresponding parts in each drawing will be designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.

[0020] <Surface-coated tools> The surface-coated tool of the present invention (hereinafter also simply referred to as "the tool of the present invention") is A substrate, and a layer I and a layer II coated in this order on a surface of the substrate, The first layer is an arc ion plating layer, The layer II is a sputtering layer, Layer I and Layer II are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and the relationship between the arithmetic mean roughness Ra0 of the surface of the base material and the arithmetic mean roughness Ra2 of the surface of the II layer satisfies the following formula (1): Surface-coated tools is: 0μm≦Ra2-Ra0<0.060μm (1)

[0021] In the present invention, the tool of the present invention may be a rolling tool or a cutting tool, but is preferably a rolling tool, particularly a forming tap.

[0022] FIG. 1 is a schematic cross-sectional view showing an example of the configuration of the surface-coated tool of the present invention.

[0023] The surface-coated tool 100 shown in FIG. 1 includes a substrate 10 and a layer I 11 and a layer II 12 coated in this order on the surface of the substrate 10. Here, the layer I 11 is an arc ion plating layer, and the layer II 12 is a sputtering layer. The layer I 11 and the layer II 12 are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating, and the relationship between the arithmetic mean roughness Ra0 of the surface of the substrate 10 and the arithmetic mean roughness Ra2 of the surface of the layer II 12 satisfies the following formula (1): 0μm≦Ra2-Ra0<0.060μm (1)

[0024] In the present invention, the term "arc ion plating layer" refers to a layer or coating formed by the arc ion plating method, and the term "sputtering layer" refers to a layer or coating formed by the sputtering method.

[0025] As described above, there are cases where a coating formed by sputtering or arc ion plating is used as a surface treatment for rolling or cutting tools, but each has advantages and disadvantages. In either case, it is difficult to achieve both the wear resistance and adhesion resistance required for the surface treatment of rolling tools.

[0026] Therefore, the present inventors attempted to perform surface treatment of a rolling tool by using both the arc ion plating method and the sputtering method. More specifically, they attempted to form a multilayer film by forming a coating on the surface of a thread forming tap by the arc ion plating method and then forming a coating by the sputtering method.

[0027] However, it has been found that simply combining arc ion plating and sputtering does not result in a surface treatment coating that is excellent in both wear resistance and adhesion resistance. More specifically, it has been found that the surface of a coating formed by arc ion plating has many protrusions due to droplets, and if a coating is formed by sputtering without any modification, the protrusions are transferred as they are, resulting in a failure to improve surface roughness and possible peeling of the coating due to poor adhesion. It has also been found that cracks originating from the droplets occur due to the load during rolling, and the entire coating formed by sputtering on the surface is carried away, potentially leading to peeling.

[0028] In response to this, the present inventors conducted further research and found that a rolling tool having the desired excellent wear resistance and adhesion resistance can be obtained by subjecting a coating formed by an arc ion plating method to an ion bombardment treatment using metal ions before forming a coating by a sputtering method. Furthermore, surprisingly, it was found that the desired effect cannot be obtained even when ion bombardment treatment using commonly used argon (Ar) ions is performed (see Comparative Example 1).

[0029] The tool of the present invention, obtained based on this finding, has a smoother surface than conventional coatings. For example, the relationship between the arithmetic mean roughness Ra0 of the substrate surface and the arithmetic mean roughness Ra2 of the surface of Layer II satisfies the above formula (1), and therefore has excellent adhesion resistance. Furthermore, because Layer I is an arc ion-plated layer, the tool of the present invention also has excellent wear resistance. Furthermore, as explained in detail in the section "Method for Manufacturing a Surface-Coated Tool" below, a specific ion bombardment treatment is performed on Layer I before forming Layer II, which makes it possible to flatten the surface of Layer I, thereby improving the adhesion between Layer I and Layer II. This is thought to result in higher wear resistance for the tool of the present invention.

[0030] That is, the tool of the present invention, particularly the thread forming tap, has excellent wear resistance and adhesion resistance.

[0031] <Base material> In the tools of the present invention, the substrate may be, for example, but not limited to, high speed tool steel (HSS), alloy tool steel, carbon tool steel, fine grained cemented carbide or ultra fine grained cemented carbide.

[0032] In the present invention, the arithmetic mean roughness Ra0 of the surface of the substrate is not particularly limited as long as the relationship with the arithmetic mean roughness Ra2 of the surface of the layer II described below satisfies the following formula (1): 0μm≦Ra2-Ra0<0.060μm (1)

[0033] In formula (1), the value of Ra2-Ra0 is less than 0.060 μm, and more specifically, may be, for example, 0.055 μm or less, 0.050 μm or less, 0.045 μm or less, 0.040 μm or less, 0.035 μm or less, 0.030 μm or less, or 0.025 μm or less, or may be 0 or greater.

[0034] In the present invention, the arithmetic mean roughness Ra of the layer or coating can be measured at three locations in accordance with JIS B 0601-2001, and the average value can be used as the arithmetic mean roughness Ra.

[0035] <Layer I> In the tool of the present invention, Layer I is an arc ion plating layer. Because Layer I is an arc ion plating layer, it has a high density and can impart wear resistance to the tool of the present invention.

[0036] The first layer may be at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating. The first layer may be composed of a single coating or two or more coatings, but from the viewpoint of further improving wear resistance, it is preferable that the first layer be composed of two or more coatings. When the first layer is composed of two or more coatings, each coating may independently be at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating.

[0037] For example, Fig. 2 is a schematic cross-sectional view showing an example of the configuration of a surface-coated tool of the present invention. The surface-coated tool 200 of the present invention shown in Fig. 2 includes a substrate 20 and layers I 21a to 21e and layer II 22, which are coated in this order on the surface of the substrate 20. As shown in Fig. 2, layer I is composed of two or more coatings 21a, 21b, 21c, 21d, and 21e. In addition, in the surface-coated tool 200, the coatings 21a, 21b, 21c, 21d, and 21e constituting layer I may each independently be at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating. More specifically, for example, layer I may have coating 21a which is a titanium nitride coating, and coatings 21b, 21c, 21d, and 21e which are all titanium carbonitride coatings.

[0038] Although Layer I may contain elements other than the elements constituting the titanium nitride coating, titanium carbide coating, and titanium carbonitride coating (i.e., N, C, and Ti), it is preferable that Layer I contain trace amounts or no elements other than N, C, and Ti. For example, as described in detail in the section "Method for Manufacturing a Surface-Coated Tool" below, ion bombardment treatment using metal ions is performed on Layer I before forming Layer II. It is preferable that Layer I contain trace amounts or no metal ions used in this ion bombardment treatment, such as chromium (Cr) ions. In other words, when measured with an energy dispersive X-ray analyzer (EDS), the Cr content of the surface of Layer I according to the present invention is preferably less than 1.0 at%, 0.9 at% or less, 0.8 at% or less, 0.7 at% or less, 0.6 at% or less, 0.5 at% or less, 0.4 at% or less, 0.3 at% or less, 0.2 at% or less, 0.1 at% or less, or 0 at%.

[0039] In the present invention, the thickness of Layer I is not particularly limited, but is preferably 1.0 μm or more and 5.0 μm or less. More specifically, the thickness of Layer I may be, for example, 1.0 μm or more, 1.5 μm or more, 2.0 μm or more, 2.5 μm or more, 3.0 μm or more, 3.5 μm or more, 4.0 μm or more, or 4.5 μm or more, or may be 5.0 μm or less, 4.5 μm or less, 4.0 μm or less, 3.5 μm or less, 3.0 μm or less, 2.5 μm or less, 2.0 μm or less, or 1.5 μm or less. In the present invention, the thickness of a layer or coating refers to the arithmetic mean thickness. Furthermore, when Layer I is composed of two or more coatings, the total thickness of these two or more coatings is defined as the thickness of Layer I.

[0040] <Layer II> In the tool of the present invention, Layer II is a sputtering layer. Because Layer II is a sputtering layer, it has high smoothness and can impart adhesion resistance to the tool of the present invention.

[0041] Layer II may be at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating. Layer II may be composed of a single coating or two or more coatings, but from the perspective of further improving wear resistance while ensuring adhesion resistance, it is preferable that Layer II be composed of a single coating. When Layer II is composed of two or more coatings, each coating may independently be at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating.

[0042] For example, the surface-coated tool 200 of the present invention shown in Fig. 2 includes a substrate 20, and layers I 21a to 21e and a layer II 22 coated in this order on the surface of the substrate 20. In Fig. 2, the layer II 22 is composed of a single coating, but it may be composed of two or more coatings.

[0043] In the present invention, the thickness of Layer II is not particularly limited, but is preferably 1.0 μm or less. More specifically, the thickness of Layer II may be, for example, 1.0 μm or less, 0.9 μm or less, 0.8 μm or less, 0.7 μm or less, 0.6 μm or less, or 0.5 μm or less, or 0.02 μm or more, 0.05 μm or more, 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more.

[0044] In the present invention, the smoother the surface of Layer II, the greater the adhesion resistance effect. Therefore, the arithmetic mean roughness Ra2 of the surface of Layer II according to the present invention may be, for example, 0.150 μm or less, 0.140 μm or less, 0.130 μm or less, 0.120 μm or less, or 0.115 μm or less. Furthermore, the lower limit of the arithmetic mean roughness Ra of the surface of Layer II is not particularly limited and may be, for example, 0.010 μm or more.

[0045] In the present invention, the maximum height roughness Rz of the surface of Layer II may be 1.300 μm or less, more specifically, for example, 1.250 μm or less, 1.200 μm or less, 1.150 μm or less, 1.100 μm or less, or 0.950 μm or less, and may be 0.500 μm or more.

[0046] In the present invention, the maximum height roughness Rz of the layer or coating can be measured at three locations in accordance with JIS B 0601-2001, and the average value can be used as the maximum height roughness Rz.

[0047] Other demographics The tool of the present invention may further include other layers as desired, as long as the effects of the present invention are not impaired.

[0048] As other layers, for example, an optional underlayer may be provided to improve adhesion between the substrate and Layer I. Furthermore, when Layer I is composed of two or more coatings, a functional layer that provides an optional function may be provided among the coatings that make up Layer I.

[0049] <<Method for manufacturing surface-coated tools>> The method for producing a surface-coated tool of the present invention (hereinafter also simply referred to as the "production method of the present invention") comprises the steps of: the tool includes a substrate and a layer I and a layer II coated in this order on a surface of the substrate; the first layer and the second layer are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and A method comprising the following steps (1) to (3): (1) forming a first layer on a substrate by an arc ion plating method; (2) subjecting the I layer to an ion bombardment treatment using metal ions; and (3) Forming a second layer by sputtering on the first layer after the ion bombardment treatment.

[0050] In the manufacturing method of the present invention, the explanation of the "tool," "layer I," and "layer II" can be found in the above-mentioned "surface-coated tool" section, so it will be omitted here.

[0051] FIG. 3 is a flow chart showing an outline of the steps involved in the manufacturing method of the present invention.

[0052] The manufacturing method of the present invention shown in FIG. 3 includes step (1) forming layer I on a substrate by arc ion plating (S1), step (2) performing ion bombardment treatment on layer I using metal ions (S2), and step (3) forming layer II on layer I after ion bombardment treatment by sputtering (S3).

[0053] <Film forming equipment> The film forming apparatus used in the manufacturing method of the present invention is not particularly limited, and one apparatus may be used, or a plurality of apparatuses may be used in combination.

[0054] 4 is a side perspective view showing a schematic diagram of an example of a film forming apparatus used in the present invention. Steps (1) to (3) according to the present invention can be performed in the film forming apparatus 500 shown in FIG.

[0055] 4, a target (arc target) 502 serving as the metal source for the coating, a metal source target 503 for ion bombardment treatment, a target (sputtering target) 504 serving as the metal source for the coating, and a rotatable substrate holder 505 on which substrates 10a and 10b can be placed are installed within a chamber 501. A power supply is attached to each of the targets 502, 503, and 504, and a bias power supply is attached to the substrate holder 505. Furthermore, the chamber 501 is equipped with a gas inlet 506 for introducing a source gas and a gas outlet 507. The pressure in the chamber 501 can be adjusted by sucking gas from a gas outlet 5072 using a vacuum pump (not shown).

[0056] <Process (1)> In step (1), the first layer is formed on the substrate by arc ion plating.

[0057] Arc ion plating is a deposition method in which a substrate and a target are placed in a film-forming device, and a high current is applied to the target to generate an arc discharge, ionizing the elements that make up the target, which are then deposited on the substrate to which a negative bias voltage is applied.

[0058] 4, substrates 10a and 10b are attached to rotary substrate holders 505, and a Ti-containing target 502 is used as the target 502, with nitrogen gas and / or acetylene gas used as the source gas. During this process, while rotating substrates 10a and 10b, a high current is applied to target 502 to generate an arc discharge, thereby ionizing the elements that make up the target. The ionized elements are deposited on substrates 10a and 10b to which a negative bias voltage is applied in an atmosphere in which a source gas is introduced from gas inlet 506, thereby forming layer I, which is at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating.

[0059] 4, two substrates, 10a and 10b, are provided, but the number may be one, or even three or more. By adjusting the amount of nitrogen gas and / or hydrocarbon gas (e.g., acetylene gas) used as the source gas, the desired titanium nitride coating, titanium carbide coating, and titanium carbonitride coating can be formed.

[0060] In step (1), the temperature inside the chamber 501 is not particularly limited and may be adjusted as appropriate within a range of, for example, 400°C to 500°C. The pressure inside the chamber 501 is not particularly limited and may be adjusted as appropriate. The voltage, current, etc. applied to the target and substrate may be adjusted as appropriate depending on the type or thickness of the desired coating.

[0061] <Process (2)> In step (2), the layer I is subjected to an ion bombardment treatment using metal ions, which removes droplets formed on the surface of the layer I by the arc ion plating method, thereby flattening the surface of the layer I.

[0062] In step (2), the metal ions used in the ion bombardment treatment may be, for example, Cr ions or Ti ions, but are preferably Cr ions.

[0063] More specifically, in step (2), for example, an ion bombardment process can be performed on the layer I formed on the substrates 10a and 10b in the film forming apparatus 500 of FIG. 4 using a target 503 containing Cr while the substrates 10a and 10b are rotated.

[0064] When performing the metal ion bombardment treatment, the bias voltage applied to the substrate may be appropriately adjusted, for example, so that the metal elements used in the ion bombardment treatment do not adhere to the substrate or adhere only in trace amounts.

[0065] Step (2) may be carried out in a vacuum or high vacuum atmosphere, and an inert gas such as argon gas may be introduced as appropriate.

[0066] <Process (3)> In step (3), the second layer is formed by sputtering on the first layer after the ion bombardment treatment.

[0067] Sputtering is a deposition method in which Ar ions generated by glow discharge are bombarded against the surface of a target material, and atoms emitted from the target are ionized and deposited on a substrate.

[0068] 4, a target containing Ti is used as the target 504, and nitrogen gas and / or acetylene gas is used as the source gas. At this time, while rotating the substrates 10a and 10b on the layer I after the ion bombardment treatment, Ar ions generated by glow discharge are bombarded against the surface of the target 504, and the Ti atoms emitted from the target 504 are ionized. Furthermore, a source gas is introduced as necessary, thereby forming the layer II, which is at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating.

[0069] <Optional Other Steps> The manufacturing method of the present invention may optionally include other steps in addition to the steps described above, such as, but not limited to, an etching step.

[0070] (etching process) For example, the manufacturing method of the present invention may further include etching the substrate before step (1). By performing the etching, fine dirt and the like adhering to the surface of the tool of the present invention can be removed.

[0071] As the etching, for example, dry etching such as reactive gas etching or reactive ion etching can be used. [Example]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0073] Example 1 In Example 1, a test tap (also referred to as an "evaluation tap") and a test piece for measurement, each having the configuration shown in FIG. 5, were manufactured.

[0074] More specifically, high-speed tool steel (HSS) was used as the substrate. Layer I, coated on the surface of the substrate, included multiple TiN and TiCN coatings formed by arc ion plating, with a total thickness of 2.0 μm. Furthermore, the surface of the top layer of Layer I (i.e., the layer adjacent to Layer II) was subjected to Cr ion bombardment treatment, and after this treatment, Layer II was formed by sputtering. The thickness of Layer II was 0.5 μm.

[0075] Comparative Example 1 In Comparative Example 1, a test tap and a test piece for measurement were produced in the same manner as in Example 1, except that Ar ion bombardment treatment was performed instead of Cr ion bombardment treatment.

[0076] Comparative Example 2 In Comparative Example 2, a test tap and a test piece for measurement were produced in the same manner as in Example 1, except that the ion bombardment treatment was not carried out.

[0077] Comparative Example 3 In Comparative Example 3, a test tap and a test piece for measurement were manufactured in the same manner as in Example 1, except that a TiN film was formed on the substrate by hollow cathode discharge, and then a TiCN film was formed thereon, and ion bombardment treatment was not performed.

[0078] <evaluation> (surface roughness measurement) For the test taps manufactured in the examples and comparative examples and the corresponding test pieces, the arithmetic mean roughness Ra and maximum height roughness Rz of the substrate before coating, and the arithmetic mean roughness Ra and maximum height roughness Rz of the surface of Layer II after coating were determined, and the results are shown in Table 1.

[0079] The arithmetic mean roughness Ra was measured at three locations using a roughness measuring device in accordance with JIS B 0601-2001, and the average value was taken as the arithmetic mean roughness Ra. The maximum height roughness Rz was measured at three locations using a roughness measuring device in accordance with JIS B 0601-2001, and the average value was taken as the maximum height roughness Rz.

[0080] (Microscopic observation) The test taps manufactured in the examples and comparative examples were observed using an electron microscope, and the observation results are shown in Figure 6(a) (Example 1), Figure 6(b) (Comparative Example 1), Figure 6(c) (Comparative Example 2), and Figure 6(d) (Comparative Example 3), respectively.

[0081] As is clear from FIGS. 6(a) to 6(d), the test tap of Example 1 had the smoothest surface and the smallest number of droplets.

[0082] (Coating adhesion evaluation using indentation in Rockwell hardness test) An indentation was made with a diamond indenter (cone) using a Rockwell hardness tester on each of the test pieces of Example 1 and Comparative Examples 1 and 2. Thereafter, each indented site was observed under an electron microscope, and the respective results are shown in Figures 7 to 9.

[0083] Furthermore, the results of each observation were evaluated based on the adhesion evaluation standard DIN VDI 3198.

[0084] FIG. 7 shows the observation results of the indentation site of Example 1. FIG. 7(b) is an enlarged view of the area enclosed by the square frame in FIG. 7(a). As is clear from FIG. 7, in the results of Example 1, only very small cracks were observed even when observed under magnification (FIG. 7(b)). This also clearly corresponds to the HF1 (pass) rank of the adhesion evaluation standard DIN VDI 3198. In other words, it was found that the coating of the test piece of Example 1 had high adhesion.

[0085] FIG. 8 shows the results of observation of the indentation site of Comparative Example 1. FIG. 8(b) is an enlarged view of the area enclosed by the square frame in FIG. 8(a). As is clear from FIG. 8, in the results of Comparative Example 1, small cracks were observed when observed under magnification (FIG. 8(b)). This corresponds to an HF1 (pass) rank in the adhesion evaluation standard DIN VDI 3198, but it was found that the adhesion was slightly inferior to that of Example 1.

[0086] Fig. 9 shows the observation results of the indentation site of Comparative Example 2. For ease of confirmation, the contrast of the photograph in Fig. 9 has been adjusted. As is clear from Fig. 9, the results of Comparative Example 2 show that Layer II (i.e., the sputtering layer) was peeled off. This also clearly corresponds to the HF6 (fail) rank of the adhesion evaluation standard DIN VDI 3198.

[0087] A Rockwell hardness test was also carried out on the test piece of Comparative Example 3. The observation results (not shown) of the indented area of ​​Comparative Example 3 were found to correspond to the HF1 (pass) rank of the adhesion evaluation standard DIN VDI 3198.

[0088] The ranks of the indentation results for each of the Examples and Comparative Examples, which correspond to the adhesion evaluation standard DIN VDI 3198, are summarized in Table 1 below.

[0089] (Vickers hardness test) The Vickers hardness of each of the test pieces of Example 1 and Comparative Examples 1 to 3 was measured under a test load of 250 mN in accordance with JIS Z 2244. The results are shown in Table 1 below.

[0090] [Table 1]

[0091] As is clear from the results in Table 1, Example 1, which underwent ion bombardment treatment using Cr ions, had the lowest arithmetic mean surface roughness of Layer II, suggesting that it had the highest adhesion resistance.

[0092] <Results of application to forming taps (rolling tools) 1> The wear resistance and adhesion resistance of each test tap of Example 1 and Comparative Example 3 were evaluated. Photographs of the condition of each tap after drilling 1,600 holes are shown in Figure 10 (Example 1) and Figure 11 (Comparative Example 3).

[0093] The hole drilling test conditions are as follows: Tap: Forming tap M4 x 0.7 Work material: S50C (carbon steel) Pilot hole diameter: 3.7 mm Tapping speed: 20 m / min Cutting fluid: Water-soluble cutting fluid emulsion concentration 5%

[0094] 10 and 11, although there was no significant difference in appearance between Example 1 and Comparative Example 3 in Figures 10(a) and 11(a), when observing the enlarged views of Figures 10(b) and 11(b), exposed portions of the substrate (base material) and adhered portions were observed at the top of the tap in Comparative Example 3. In contrast, in Example 1, there was no exposed substrate.

[0095] That is, it was found that Example 1 used as a thread forming tap was superior in wear resistance and adhesion resistance compared to Comparative Example 3.

[0096] <Results of application to forming taps (rolling tools) 2> The wear resistance and adhesion resistance of each test tap of Example 1 and Comparative Example 3 were evaluated. Photographs of the state of each tap after drilling 880 holes are shown in Figure 12 (Example 1) and Figure 13 (Comparative Example 3).

[0097] The hole drilling test conditions are as follows: Tap: Forming tap M2 x 0.4 Work material: SUS304 (material prone to adhesion) Pilot hole diameter: 1.82 mm Tapping speed: 5 m / min Cutting fluid: Water-soluble cutting fluid emulsion concentration 5%

[0098] As is clear from Figures 12 and 13, there was no significant difference in appearance between Example 1 and Comparative Example 3 in Figures 12(a) and 13(a), but when observing the enlarged views of Figures 12(b) and 13(b), exposed areas of the substrate (base material) and adhered areas were observed in Comparative Example 3. In contrast, although adhered areas were observed in Example 1, they were not as large as in Comparative Example 3. Furthermore, there was no exposed substrate in Example 1.

[0099] From this result, it was found that the test tap of Example 1 was superior to that of Comparative Example 3 in wear resistance and adhesion resistance. [Explanation of symbols]

[0100] 10, 20, 10a, 10b base material 11 Layer I 12, 22 Layer II 21a, 21b, 21c, 21d, 21e Coatings that make up Layer I 100, 200 Surface coated tools 500 Film deposition equipment 501 Chamber 502, 503, 504 targets 505 Substrate Holder 506 Gas inlet 507 Gas exhaust port

Claims

1. A method for manufacturing a surface-coated tool, comprising the steps of: the tool includes a substrate and a layer I and a layer II coated in this order on a surface of the substrate; the layer I and the layer II are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and The method includes the following steps (1) to (3): (1) forming the layer I on the substrate by an arc ion plating method; (2) subjecting the I layer to an ion bombardment treatment using metal ions; and (3) forming a second layer by a sputtering method on the first layer after the ion bombardment treatment; and In the step (2), the metal ion is a Cr ion. method.

2. The arithmetic mean roughness Ra of the surface of the substrate is 0, and the arithmetic mean roughness Ra of the surface of the II layer is ２ The method according to claim 1, wherein the relationship between the 0μm≦Ra ２ -Ra ０ <0.060μm (1)

3. The method according to claim 1 , wherein the arithmetic mean roughness Ra of the surface of the second layer is 0.150 μm or less.

4. The method according to any one of claims 1 to 3, wherein the tool is a forming tap.

5. A substrate, and a layer I and a layer II coated in this order on a surface of the substrate, the I layer is an arc ion plating layer, the second layer is a sputtering layer, the surface of the I layer contains less than 1.0 at% Cr; the layer I and the layer II are each independently at least one of a titanium nitride coating, a titanium carbide coating, and a titanium carbonitride coating; and The arithmetic mean roughness Ra of the surface of the substrate ０ and the arithmetic mean roughness Ra of the surface of the II layer ２ The relationship satisfies the following formula (1): Surface coated tools: 0μm≦Ra ２ -Ra ０ <0.060μm (1) 6. The tool according to claim 5, wherein in the formula (1), the value of Ra 2 -Ra 0 is 0.030 μm or less.

7. The tool according to claim 5, wherein the arithmetic mean roughness Ra of the surface of the second layer is 0.150 μm or less.

8. The thickness of the layer I is 1.0 μm or more and 5.0 μm or less, and The thickness of the layer II is 1.0 μm or less.

6. The tool of claim 5.

9. The tool according to claim 5, wherein the maximum height roughness Rz of the surface of the II layer is 1.300 μm or less.

10. The tool of claim 5 , wherein the Layer I is comprised of two or more coatings.

11. The tool according to any one of claims 5 to 10, wherein the tool is a forming tap.

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