JP2012208073A - Dimension measuring jig - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dimension measuring jig whose surface comprises a hard film excellent in abrasion resistance and adhesiveness and that can drastically reduce a frequency of replacement because of its longer-operating life.SOLUTION: A dimension measuring jig comprises a hard film 1 that is formed on a surface of a substrate 2. The hard film 1 comprises: a ground layer 1a that is formed directly on the surface of the substrate 2 and is mainly made of chrome; a mixed layer 1b that is formed on the ground layer 1a and is mainly made of tungsten carbide and diamond-like carbon; and a surface layer 1c that is formed on the mixed layer 1b and is mainly made of diamond-like carbon. With respect to the mixed layer 1b, a content percentage of tungsten carbide in the mixed layer 1b decreases and that of diamond-like carbon in the mixed layer 1b increases, in a continuous or step-by-step manner, in a direction from the ground layer 1a side toward the surface layer 1c side.

Description

  The present invention relates to a jig for measuring dimensions such as gauges, surface plates, and model parts used for measuring the dimensions, tightening torque, shape, etc. of various machine parts and various molding dies. The present invention relates to a dimension measuring jig formed with a hard film containing carbon.

  The hard carbon film is a hard film generally called diamond-like carbon (hereinafter referred to as DLC. A film / layer mainly composed of DLC is also referred to as a DLC film / layer). In addition, hard carbon has various names such as hard amorphous carbon, amorphous carbon, hard amorphous carbon, i-carbon, diamond-like carbon, and these terms are not clearly distinguished.

  The essence of DLC in which such terms are used is structurally an intermediate structure of both diamond and graphite mixed. It is as hard as diamond and has excellent wear resistance, solid lubricity, thermal conductivity, chemical stability, and corrosion resistance. As a method for forming such a DLC film, physical vapor deposition (hereinafter referred to as PVD) such as sputtering or ion plating, chemical vapor deposition (hereinafter referred to as CVD), unbalanced magnetron sputtering ( Hereinafter, a method such as UBMS) is employed.

  On the other hand, as a jig / apparatus / part (hereinafter referred to as “dimension measuring jig” in the present invention) used for measuring dimensions, tightening torque, shape, etc. of various machine parts and various molding dies, block Various gauges such as gauges, pin gauges, dial gauges, plug gauges, plug gauges, film gauges, surface plates used when measuring dimensions using block gauges, product model dimensions (bearing inner and outer rings, cages, rolling elements) Also known are model parts such as a tightening torque confirmation model, dimension measuring instruments such as calipers and micrometers, and the like.

  As an example of a model part for dimensional management of a machine part, there is a plug gauge for measuring the dimension of a female screw. The plug gauge is fitted into a screw hole of a female screw and inspects its dimensions. It has a gauge part with male threads corresponding to female threads, and it corresponds to the internal and external thread plug gauges and female thread internal diameters for checking the outer diameter, effective diameter, pitch diameter, etc. An inner diameter plug gauge having a cylindrical gauge and inspecting the inner diameter of the female screw is defined by JIS and the like.

  In such a plug gauge, a technique for improving the wear resistance by coating a hard film such as TiN or CrN on the surface has been proposed. However, since TiN film and CrN film have large variations in film thickness, it is difficult to satisfy the high dimensional accuracy required for the plug gauge, and it is substantially difficult to apply. Moreover, since TiN film and CrN film are formed by the AIP (arc ion plating) method, coarse particles called droplets (generated at the arc discharge part) adhere to the surface, resulting in rough surface and lubricity. There is a problem that the workability is deteriorated due to damage at the fitting part between the plug gauge and the female screw, or a problem that the wear resistance is not sufficient and the replacement interval is short.

  In order to solve this problem, a method of forming a DLC film of 2 μm or less on the surface of the plug gauge by the CVD method has been proposed (see Patent Document 1). Moreover, what forms a DLC film | membrane on the surface of the plug gauge used for measuring internal diameter dimensions, such as a hole processed into the target object, is proposed (refer patent document 2).

  In addition, as a method of forming a DLC film, for example, a mechanism that can remove cathode material particles called droplets generated from the cathode of an arc discharge part is attached, and arc ion plating that can form a DLC film with less unevenness on the surface is provided. A filtered arc method has been proposed (see Patent Document 3). Further, a DLC film having excellent adhesion by forming a DLC film by the UBMS method has been proposed (see Patent Document 4).

JP 2006-208116 A JP 2006-177908 A JP 2007-046144 A JP 2002-256415 A

  However, the DLC film formed by the CVD method as in Patent Document 1 is inferior in wear resistance and adhesion compared to the DLC film formed by the PVD method, and is therefore suitable as an exemplary part for dimensional control. That's not true. In Patent Document 1, no measures for improving adhesion such as providing an intermediate layer are taken.

  In Patent Document 2, a film is formed using the UBMS method, and a plating layer is provided between the DLC layer and the base material. The adhesion between the plating layer and the base material is achieved by the UBMS method. Significantly inferior to the filmed intermediate layer. For this reason, it cannot be said that the adhesion strength of the entire film is sufficient. In addition, since it is difficult to manage the thickness of the plating layer and it is difficult to reduce the thickness, it is not optimal as an exemplary part. Further, in order to improve the adhesion, it has been proposed to use a metal element in the intermediate layer. However, the adhesion may not be improved depending on the film structure or film formation conditions of the intermediate layer.

  In this way, the existing model parts are hard film treated (CrN, TiN, DLC, etc.) on the surface to try to extend the life, but are insufficient in terms of dimensional accuracy, wear resistance, and adhesion It is difficult to use for a long time.

  When a DLC film is formed on a curved surface portion of the surface of the dimension measuring jig, the residual stress in the film increases depending on the film structure and film formation conditions, and there is a possibility that the film is peeled off immediately after the film formation. Even if it does not peel off immediately after film formation, it may peel off when subjected to a load during use. For this reason, high adhesiveness is required. In addition, in the case of an exemplary part for confirming the tightening torque, in order to manage the dimensions of the housing, the exemplary part is press-fitted and the torque when the exemplary part is slid back and forth is detected. It is necessary to have high wear resistance.

  As a method for forming a DLC film, the method of Patent Document 3 gives priority to wear resistance and is inferior in adhesiveness, and thus is considered difficult to apply to a dimension measuring jig. Further, in the method of Patent Document 4, since attention is paid only to the adhesion with the base material, it is difficult to provide sufficient wear resistance as a dimension measuring jig under the conventional film forming conditions. Conceivable.

  The present invention has been made in order to cope with such a problem, and has a hard film having excellent wear resistance and adhesion on the surface, a long-life dimension measuring jig that can greatly reduce the number of replacements. The purpose is to provide.

  The dimension measuring jig according to the present invention has a hard film formed on the surface of a base material, and the hard film is mainly composed of chromium (hereinafter referred to as Cr) formed directly on the surface of the base material. A mixed layer mainly composed of tungsten carbide (hereinafter referred to as WC) and DLC formed on the underlying layer, and mainly composed of DLC formed on the mixed layer. The mixed layer has a WC content in the mixed layer that decreases continuously or stepwise from the base layer side to the surface layer side, It is a layer in which the content of DLC in the mixed layer increases.

  It has a curved surface on the surface of the substrate. Here, the curved surface portion is a portion that constitutes at least a part of the surface of the base material on which the hard film is formed, and is a portion that is not a flat surface.

The hard film is brought into contact with SUJ2 hardened steel having a surface roughness Ra of 0.01 μm or less and a Vickers hardness Hv of 780 by applying a load with a maximum contact surface pressure of 0.5 GPa of Hertz. The specific wear amount of the hard film is less than 200 × 10 ⁻¹⁰ mm ³ / (N · m) when the counterpart material is rotated for 30 minutes at a rotational speed of 05 m / s.

  The hard film is characterized in that the sum of the indentation hardness average value and the standard deviation value is 25 to 45 GPa.

  The hard film has a critical peel load in a scratch test of 50 N or more.

  The surface layer has an inclined layer portion whose hardness increases continuously or stepwise from the mixed layer side on the side adjacent to the mixed layer.

  The surface layer is a layer formed using a UBMS apparatus using argon (hereinafter referred to as Ar) gas as a sputtering gas, and a graphite target and a hydrocarbon-based gas are used in combination as a carbon supply source. The ratio of the introduction amount of the hydrocarbon-based gas to the introduction amount 100 of Ar gas into the device is 1 to 5, the degree of vacuum in the device is 0.2 to 0.8 Pa, The film is formed by depositing carbon atoms generated from the carbon supply source on the mixed layer under a condition in which a bias voltage to be applied is 70 to 150 V. Further, the hydrocarbon gas is methane gas.

  Note that the bias potential with respect to the base material is applied so as to be negative with respect to the ground potential. For example, the bias voltage of 150 V means that the bias potential of the base material is −150 V with respect to the ground potential. Show.

  The inclined layer portion of the surface layer is formed while raising the bias voltage applied to the substrate continuously or stepwise.

  The underlayer and the mixed layer are layers formed using a UBMS apparatus using Ar gas as a sputtering gas, and the mixed layer is formed on a graphite target serving as a carbon supply source continuously or stepwise. The film is formed while increasing the sputtering power applied and decreasing the power applied to the WC target.

  The hard film has a thickness of 0.5 to 3 μm, and the ratio of the thickness of the surface layer to the thickness of the hard film is 0.8 or less.

  The base material is made of a cemented carbide material or an iron-based material. Further, a nitride layer is formed by nitriding treatment on the surface on which the hard film is formed before the hard film is formed. Further, the nitriding treatment is a plasma nitriding treatment, and the surface hardness after the nitriding treatment is Vvs hardness of Hv1000 or more.

  The dimension measuring jig is a gauge, a surface plate, model parts, or a member constituting them. The dimension measuring jig is a micrometer or a caliper.

  The dimension measuring jig of the present invention is formed by forming a hard film having a predetermined film structure containing DLC on the surface of a base material. The underlayer made of Cr formed directly on each surface has good compatibility with iron-based materials and the like, and has excellent adhesion compared to W and Si. In addition, WC used for the mixed layer has intermediate hardness and elastic modulus between Cr and DLC, and concentration of residual stress after film formation hardly occurs. Further, the mixed layer of WC and DLC has a gradient composition, so that WC and DLC are physically coupled.

  Due to the above structure, the hard film has excellent peeling resistance while being formed on the surface of the base material of a dimension measuring jig that is reciprocally slid, and can exhibit the original characteristics of DLC. As a result, the dimension measuring jig of the present invention is excellent in the adhesion and wear resistance of the hard film on the surface, has a long life, and can greatly reduce the number of replacements.

It is a schematic cross section which shows the structure of the hard film | membrane formed into a film by the dimension measuring jig of this invention. It is a schematic diagram which shows the film-forming principle of UBMS method. It is a schematic diagram of the UBMS apparatus provided with the AIP function. It is a figure which shows a friction tester. It is a figure which shows adhesive evaluation criteria.

  A hard film such as a DLC film has a residual stress in the film, and the residual stress varies greatly depending on the film structure, film forming conditions, and substrate shape. As a result of intensive studies, the inventors of the present invention have a hard film formed on the substrate surface of the dimension measuring jig, which is composed of a base layer (Cr), a mixed layer (WC / DLC slope), and a surface layer (DLC). By limiting to a predetermined structure, it has been found that even when a curved surface is included on the surface of the base material, the peel resistance can be greatly improved, and peeling and wear of the hard film can be prevented when using a jig. It was. The present invention has been made based on such findings.

  The dimension measuring jig which is the object of the present invention is a jig, tool, or part used when measuring dimensions, tightening torque, shape, or the like of various machine parts or various molding dies. For example, various gauges such as block gauges, pin gauges, dial gauges, plug gauges, plug gauges, film gauges, surface plates used when measuring dimensions using block gauges (with sliding with block gauges and products), product shapes Dimensional examples (bearing inner / outer rings, cages, rolling elements), dimensional measuring instruments such as vernier calipers, micrometers, etc. Specifically, the model parts are used when measuring the inner diameter of the bearing inner ring, the outer diameter of the outer ring of the bearing, or the dimension of the rolling element, or used when measuring the inner diameter dimension of the housing that is fitted with the outer ring of the spherical bearing. There is.

  Although it does not specifically limit as a material of the base material of the dimension measuring jig of this invention, A cemented carbide material or an iron-type material can be used. As a cemented carbide material, in addition to a WC-Co alloy having the most excellent mechanical properties, a WC-TiC-Co alloy, a WC-TaC-Co alloy having improved oxidation resistance as a cutting tool, WC-TiC-TaC-Co based alloys and the like can be mentioned. Examples of iron-based materials include carbon tool steel, high-speed tool steel, alloy tool steel, stainless steel, bearing steel, and free-cutting steel.

  In these substrates, the hardness of the surface on which the hard film is formed is preferably Hv650 or higher in terms of Vickers hardness. By setting it as Hv650 or more, a hardness difference with a hard film | membrane (underlayer) can be decreased and adhesiveness can be improved.

  On the surface on which the hard film is formed, it is preferable that a nitride layer is formed by nitriding before forming the hard film. As the nitriding treatment, it is preferable to perform a plasma nitriding treatment in which an oxide layer that hinders adhesion is hardly generated on the surface of the base material. Further, the surface hardness after nitriding is preferably Vickers hardness of Hv1000 or more in order to further improve the adhesion to the hard film (underlayer).

  The surface roughness Ra of the surface on which the hard film is formed is preferably 0.05 μm or less. When the surface roughness Ra exceeds 0.05 μm, it is difficult to form a hard film at the tip of the projection having the roughness, and the film thickness is locally reduced.

  The structure of the hard film will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing the structure of a hard film 1 formed on the surface of a substrate in the dimension measuring jig of the present invention. As shown in FIG. 1, the hard film 1 includes (1) an underlayer 1a mainly composed of Cr directly formed on the surface 2a of the base material 2, and (2) formed on the underlayer 1a. The mixed layer 1b mainly composed of WC and DLC and (3) the surface layer 1c mainly composed of DLC formed on the mixed layer 1b. Here, in the mixed layer 1b, the content of WC in the mixed layer decreases continuously or stepwise from the base layer 1a side to the surface layer 1c side, and the DLC content in the mixed layer This is a layer with a higher rate.

  Since the underlayer 1a is a layer mainly composed of Cr, it has good compatibility with a base material made of a cemented carbide material or an iron-based material, and compared with the case where W, Ti, Si or the like is used. Excellent adhesion.

  The WC used for the mixed layer 1b has intermediate hardness and elastic modulus between Cr and DLC, and concentration of residual stress after film formation hardly occurs. As shown in each comparative example to be described later, when the underlayer is other than Cr, or when the mixed layer is a layer mainly composed of Cr and DLC in accordance with the underlayer, the peelability in the Rockwell indentation test Inferior to Thus, in the case where a hard film containing DLC having excellent peel resistance is to be formed on the surface of the dimension measuring jig, material selection in the intermediate layer (the base layer 1a and the mixed layer 1b) is also an important factor. Become.

  In addition, since the mixed layer 1b has a gradient composition in which the content of WC is small toward the surface layer 1c side and the content of DLC is high, the adhesion between both the base layer 1a and the surface layer 1c is improved. Excellent. In particular, in the mixed layer, WC and DLC are physically bonded, and the DLC content is increased on the surface layer 1c side, so that the adhesion between the surface layer 1c and the mixed layer 1b is excellent.

The surface layer 1c is a film mainly composed of DLC. The surface layer 1c preferably has an inclined layer portion 1d whose hardness increases continuously or stepwise from the mixed layer 1b side on the side adjacent to the mixed layer 1b. This is a portion obtained by changing (raising) the bias voltage continuously or stepwise in order to avoid a sudden change in the bias voltage when the bias voltage is different between the mixed layer 1b and the surface layer 1c. The inclined layer portion 1d changes the bias voltage in this way, and as a result, the hardness is inclined as described above. The reason why the hardness increases continuously or stepwise is that the composition ratio between the graphite structure (sp ² ) and the diamond structure (sp ³ ) in the DLC structure is biased toward the latter as the bias voltage increases. Thereby, there is no sudden hardness difference between the mixed layer and the surface layer, and the adhesion between the mixed layer 1b and the surface layer 1c is further improved.

  The thickness of the hard film 1 (total of three layers) is preferably 0.5 to 3.0 μm. If the film thickness is less than 0.5 μm, the abrasion resistance and mechanical strength may be inferior, and if it exceeds 3.0 μm, the film is easily peeled off. Furthermore, the ratio of the thickness of the surface layer 1c to the thickness of the hard film 1 is preferably 0.8 or less. If this ratio exceeds 0.8, the gradient structure for physical coupling of WC and DLC in the mixed layer 1b becomes a discontinuous structure, so that the adhesiveness is likely to deteriorate.

  By making the hard film 1 into a three-layer structure of the base layer 1a, the mixed layer 1b, and the surface layer 1c having the above composition, the peel resistance is excellent.

The physical properties of the hard film 1 are SUJ2 hardened steel having a surface roughness Ra of 0.01 μm or less and a Vickers hardness Hv of 780, and a contact with a load of 0.5 GPa maximum contact surface pressure of Hertz. The specific wear amount of the hard film is preferably less than 200 × 10 ⁻¹⁰ mm ³ / (N · m) when the counterpart material is rotated for 30 minutes at a rotational speed of 0.05 m / s. If the specific wear amount is less than 200 × 10 ⁻¹⁰ mm ³ / (N · m) in this test, the wear resistance is excellent, and generation of wear powder can be prevented even when the jig is slid back and forth.

  Moreover, it is preferable that the sum total of the average value of indentation hardness and a standard deviation value is 25-45 GPa. Within this range, a high effect is exhibited even in abrasive wear that occurs when a hard foreign object intervenes on the sliding surface.

  Moreover, it is preferable that the critical peeling load in a scratch test is 50 N or more. The method for measuring the critical peel load in the scratch test is as shown in the examples described later. When the critical peel load is less than 50 N, the hard film is likely to peel when the jig is used under high load conditions. Even if the critical peeling load is 50 N or more, the film may be easily peeled off depending on the case unless it is a film structure as in the present invention.

  Hereinafter, a method for forming the hard film will be described. The hard film is obtained by forming the base layer 1a, the mixed layer 1b, and the surface layer 1c in this order on the substrate surface of the dimension measuring jig.

  The underlayer 1a and the mixed layer 1b are preferably formed using a UBMS apparatus using Ar gas as a sputtering gas. The film forming principle of the UBMS method using the UBMS apparatus will be described with reference to the schematic diagram shown in FIG. In the drawing, the base material 12 is a base material of a dimension measuring jig to be formed, but is schematically shown as a flat plate. As shown in FIG. 2, an inner magnet 14 a and an outer magnet 14 b having different magnetic characteristics are arranged in the central portion and the peripheral portion of the round target 15, and the magnet 14 a is formed while forming a high-density plasma 19 near the target 15. , 14 b, a part 16 a of the magnetic force lines 16 reaches the vicinity of the base material 12 connected to the bias power source 11. The Ar plasma generated during the sputtering along the magnetic force lines 16a can be diffused to the vicinity of the base material 12. In such a UBMS method, an ion assist effect that causes Ar ions 17 and electrons to reach the base material 12 in a larger amount than the ordinary sputtering along the magnetic field lines 16a reaching the vicinity of the base material 12 due to the ion assist effect. A dense film (layer) 13 can be formed.

  As the target 15, a Cr target is used when forming the base layer 1a, and a WC target and a graphite target are used together when forming the mixed layer 1b. The target used for each layer is sequentially replaced every time the layers are formed.

  The mixed layer 1b is formed in a continuous or stepwise manner while increasing the sputtering power applied to the graphite target serving as the carbon supply source and decreasing the power applied to the WC target. Thereby, it can be set as the layer of the gradient composition which the content rate of WC becomes small toward the surface layer 1c side, and the content rate of DLC becomes high.

  The formation of the surface layer 1c is also preferably performed using a UBMS apparatus using Ar gas as the sputtering gas. More specifically, the surface layer 1c uses this apparatus, uses a graphite target and a hydrocarbon-based gas in combination as a carbon supply source, and the hydrocarbon system with respect to the introduction amount 100 of the Ar gas into the apparatus. Under the conditions that the ratio of the amount of gas introduced is 1 to 5, the degree of vacuum in the apparatus is 0.2 to 0.8 Pa, and the bias voltage applied to the substrate is 70 to 150 V, the carbon source It is preferable that the carbon atoms generated from the above are deposited on the mixed layer 1b. This preferable condition will be described below.

  Adhesiveness with the mixed layer 1b can be improved by using a graphite target and a hydrocarbon-based gas in combination as a carbon supply source. As the hydrocarbon-based gas, methane gas, acetylene gas, benzene and the like can be used, and are not particularly limited. However, methane gas is preferable from the viewpoint of cost and handleability.

  By setting the ratio of the introduction amount of the hydrocarbon-based gas to 1 to 5 (volume part) with respect to 100 introduction (volume part) of Ar gas into the UBMS apparatus (in the film formation chamber), the surface layer The adhesion with the mixed layer 1b can be improved without deteriorating the wear resistance of 1c.

  The degree of vacuum in the UBMS apparatus (inside the film forming chamber) is preferably 0.2 to 0.8 Pa as described above. More preferably, it is 0.25 to 0.8 Pa. If the degree of vacuum is less than 0.2 Pa, the amount of Ar gas in the chamber is small, so that Ar plasma is not generated and film formation may not be possible. On the other hand, if the degree of vacuum is higher than 0.8 Pa, the reverse sputtering phenomenon tends to occur and the wear resistance may be deteriorated.

  The bias voltage applied to the substrate is preferably 70 to 150 V as described above. More preferably, it is 100-150V. When the bias voltage is less than 70V, densification does not proceed and the wear resistance is extremely deteriorated, which is not preferable. On the other hand, when the bias voltage exceeds 150 V, reverse sputtering tends to occur, and the wear resistance may be deteriorated. On the other hand, if the bias voltage is too high, the surface layer becomes too hard and may be easily peeled off when the jig is used.

  Moreover, it is preferable that the introduction amount of Ar gas which is sputtering gas is 40-150 ml / min. More preferably, it is 50-150 ml / min. When the Ar gas flow rate is less than 40 ml / min, Ar plasma is not generated and film formation may not be possible. On the other hand, if the Ar gas flow rate is higher than 150 ml / min, the reverse sputtering phenomenon tends to occur, so that the wear resistance may be deteriorated. When the amount of Ar gas introduced is large, the collision probability between Ar atoms and carbon atoms increases in the film forming chamber. As a result, the number of Ar atoms reaching the film surface is reduced, the effect of compacting the film by Ar atoms is reduced, and the wear resistance of the film is deteriorated.

  As described above, the inclined layer portion 1d of the surface layer 1c is obtained by forming a film while increasing the bias voltage applied to the substrate continuously or stepwise.

  As a hard film to be formed on the dimension measuring jig of the present invention, a hard film was formed on a predetermined substrate, and the physical properties of the hard film were evaluated. These will be described below as examples, comparative examples, and reference examples.

The formation conditions of the base material, UBMS apparatus, sputtering gas, underlayer and mixed layer used for evaluation of the hard film are as follows.
(1) Base material: Base material shown in each table (2) Base material dimension: Mirror surface (about Ra 0.005 μm) disc (φ48 mm × φ8 mm × 7 mm)
(3) UBMS device: manufactured by Kobe Steel; UBMS202 / AIP composite device (4) Sputtering gas: Ar gas (5) Formation conditions of underlayer and mixed layer Underlayer: about 5 × 10 ⁻³ Pa in the film formation chamber The substrate was baked with a heater, the substrate was baked with a heater, the substrate surface was etched with Ar plasma, and a Cr layer was formed using a Cr target by the UBMS method. In addition, when using it as base layers other than Cr, it formed on the same conditions except using a corresponding target.
Mixed layer: The inside of the film forming chamber is evacuated to about 5 × 10 ⁻³ Pa, the substrate is baked with a heater, the substrate surface (or the Cr layer surface) is etched with Ar plasma, and then the WC target and The sputtering power applied to the graphite target was adjusted to incline the composition ratio of WC and DLC. In addition, when it was set as the mixed layer other than WC, it formed on the same conditions except using a corresponding target.
(6) The conditions for forming the surface layer are shown in each table.

  An outline of the UBMS 202 / AIP combined apparatus is shown in FIG. FIG. 3 is a schematic diagram of a UBMS apparatus having an arc ion plating (hereinafter referred to as AIP) function. As shown in FIG. 3, the UBMS 202 / AIP combined device instantaneously vaporizes and ionizes the AIP evaporation source material 21 by using vacuum arc discharge to the base material 23 arranged on the disk 22. This is deposited on the base material 23 to increase the plasma density in the vicinity of the base material 23 and increase the ion assist effect by the non-equilibrium magnetic field of the sputtering evaporation source material (target) 24. (See FIG. 2), this is an apparatus having a UBMS function capable of controlling the characteristics of the film deposited on the substrate. By this apparatus, a composite film in which an AIP film and a plurality of UBMS films (including a composition gradient) are arbitrarily combined can be formed on a substrate. In this embodiment, a base layer, a mixed layer, and a surface layer are formed as a UBMS film on a base material.

Example 1 to Example 8, Example 10, Example 11, Comparative Example 1 to Comparative Example 4, Reference Example 1 to Reference Example 7
The substrates shown in Tables 1 to 3 were ultrasonically cleaned with acetone and then dried. After drying, the substrate was attached to a UBMS / AIP composite apparatus, and an underlayer and a mixed layer of the materials shown in each table were formed under the above-described formation conditions. On top of that, a DLC film as a surface layer was formed under the film forming conditions shown in each table to obtain a test piece having a hard film. Note that “degree of vacuum” in each table is the degree of vacuum in the film forming chamber in the above apparatus. The obtained specimens were subjected to the following abrasion test, Rockwell indentation test (other than the reference example), film thickness test, hardness test, and scratch test. The results are shown in each table.

Example 9
Manufactured by JEOL Ltd .: A substrate (Vickers hardness Hv1000) subjected to plasma nitrogen treatment using a radical nitriding apparatus was ultrasonically cleaned with acetone and then dried. After drying, the base material was attached to a UBMS / AIP composite apparatus, and an underlayer (Cr) and a mixed layer (WC / DLC) having the materials shown in Table 1 were formed under the above-described formation conditions. A DLC film, which is a surface layer, was formed on the film formation conditions shown in Table 1 to obtain a test piece having a hard film. About the obtained test piece, it uses for the test similar to Example 1, and the result is written together in Table 1. FIG.

<Friction test>
The obtained specimen was subjected to a friction test using a friction tester shown in FIG. 4A shows a front view, and FIG. 4B shows a side view. SUJ2 hardened steel having a surface roughness Ra of 0.01 μm or less and a Vickers hardness Hv of 780 is attached to the rotating shaft as a mating member 32, the test piece 31 is fixed to the arm portion 33, and a predetermined load 34 is applied to the upper part of the drawing. And a lubricant is interposed between the test piece 31 and the mating member 32 for 30 minutes at a rotation speed of 0.05 m / s under a maximum contact surface pressure of 0.5 GPa at room temperature (25 ° C.). Instead, the load cell 35 detected the frictional force generated between the counterpart material 32 and the test piece 31 when the counterpart material 32 was rotated. From this, the specific wear amount was calculated.

<Rockwell indentation test>
When the diamond indenter was driven into the test piece substrate with a load of 150 kg, the state of occurrence of peeling around the indentation was observed. The observed peeling occurrence state was evaluated according to the evaluation criteria shown in FIG. When the amount of peeling generated is small as shown in FIG. 5A, it is evaluated that the adhesiveness is excellent, and “◯” mark is given, and peeling is partially generated as shown in FIG. 5B. Is evaluated as having poor adhesion, and a mark “△” is recorded, and when peeling occurs all around as shown in FIG. did.

<Film thickness test>
The film thickness of the hard film of the obtained test piece was measured using a surface shape / surface roughness measuring instrument (Taylor Hobson Co., Ltd .: Foam Talisurf PGI830). The film thickness was obtained by masking a part of the film forming portion and determining the level difference between the non-film forming portion and the film forming portion.

<Hardness test>
The indentation hardness of the obtained test piece was measured using a nanoindenter (G200) manufactured by Agilent Technologies. In addition, the measured value has shown the average value of the depth (location where hardness is stabilized) which is not influenced by surface roughness, and is measuring 10 each test piece.

<Scratch test>
The obtained test piece was subjected to a scratch test using Nanotech: Level Test RST, and the critical peel load was measured. Specifically, the obtained test piece was tested with a diamond indenter with a tip radius of 200 μm at a scratch speed of 10 mm / min and a load load speed of 10 N / mm (continuously increasing the load), and judged on the testing machine screen. Then, the load at which the area of the exposed base material reached 50% with respect to the frictional trace on the screen (length in the friction direction 375 μm, width about 100 μm) was measured as the critical peel load.

  As shown in Table 1, it can be seen that the hard film of each example is excellent in wear resistance and adhesion. Further, in Comparative Examples 1 to 4 in which the underlayer and the intermediate layer were different from the present invention, peeling was observed in the Rockwell indentation test.

  Next, in order to confirm the durability of the dimension measuring jig, the following test was performed.

<Plug gauge test A>
Plug gauge material: SUJ2 (Vickers hardness 780 Hv), φ22 mm × φ8 mm × t6 mm sintered metal parts (copper-iron system) were subjected to a plug gauge pass test through a hole of φ8. The inner diameter dimension of the sintered metal part used for the test is adjusted so as to fall within a dimension of φ8.01 mm ± 0.01 mm. Pass the plug gauge (φ8mm ± 0.005mm × L50mm, Ra = 0.01μm, roundness 0.001mm) surface-treated under the conditions shown in Table 4 through this sintered part inner diameter to confirm the inner diameter did. Since the inner diameter portion of the sintered part and the plug gauge slide, the plug gauge is damaged and worn when the threading number increases. For measuring the roundness, Talirond 365 manufactured by Taylor Hobson was used. One million sintered metal parts were tested, and the plug gauge with a roundness of less than 0.002 mm (amount of change less than 0.001 mm) was “◯”, and the roundness was 0.002-0. Those with 004 mm were recorded as “Δ”, and those with roundness exceeding 0.004 mm were recorded as “x”. The results are shown in Table 4.

<Plug gauge test B>
Plug gauge material: SUJ2 (Vickers hardness 780 Hv), φ50 mm × φ100 mm × t50 mm housing made of FC200 (cast iron) was subjected to a plug gauge pass test through a hole of φ50 mm. The inner diameter of the FC200 housing used for the test is adjusted so as to fall within the dimension of φ50 (0.000 to +0.02 mm). A plug gauge (φ50 mm ± 0.002 mm × L80 mm, Ra = 0.5 μm) subjected to surface treatment under the conditions shown in Table 4 was passed through this housing, and the inner diameter was confirmed. Since the housing and the plug gauge slide, the plug gauge is damaged and worn when the number of passes increases. Thorough tests were conducted on 100,000 housings, and the roundness of the plug gauge was less than 0.002 mm (change amount less than 0.001 mm), and the roundness was 0.002 to 0.004 mm. Was recorded as “Δ”, and the roundness exceeding 0.004 mm was recorded as “x”. The results are shown in Table 4.

<Caliper measurement test>
Vernier caliper material: SUS304 (Vickers hardness 780 Hv), Vernier caliper working part: 0 to 150 mm (indenter flat part for dimension measurement: 4 mm × 10 mm, flat part surface roughness: 0.005 μm, product dimensions are measured at this part, dimensions Using a caliper with a pressing force of 100 g), the outer ring outer diameter of 1 million bearings corresponding to 608 was measured, and the wear state of the caliper flat portion was observed. The wear depth with respect to the reference surface was determined using a surface roughness measuring instrument (made by Taylor Hobson: Foam Talysurf PGI830). The case where the wear depth was less than 1 μm was recorded as “◯”, the case where the wear depth was 1 μm or more and less than 3 μm was “Δ”, and the case where it was 3 μm or more was recorded as “X”. The results are shown in Table 4.

  As shown in Table 4, it can be seen that the dimension measuring jig of the present invention has a small deformation amount and can extend the life significantly even after measuring 100,000 to 1,000,000 products.

  The dimension measuring jig of the present invention has a hard film with excellent wear resistance and adhesion on the surface, and has a long life and can greatly reduce the number of replacements. Therefore, the dimensions and tightening torque of various machine parts and various molds It can be suitably used as gauges, surface plates, model parts, etc. used when measuring the shape and the like.

1 Hard Film 2 Base Material 11 Bias Power Supply 12 Base Material 13 Film (Layer)
DESCRIPTION OF SYMBOLS 15 Target 16 Magnetic field line 17 Ar ion 18 Ionized target 19 High density plasma 21 AIP evaporation source material 22 Disc 23 Base material 24 Sputter evaporation source material (target)
31 Test piece 32 Counterpart 33 Arm part 34 Load 35 Load cell

Claims (16)

A dimension measuring jig formed by forming a hard film on the surface of a substrate,
The hard film includes a base layer mainly composed of chromium directly formed on the surface of the base material, and a mixed layer mainly composed of tungsten carbide and diamond-like carbon formed on the base layer. And a film having a structure composed of a surface layer mainly composed of diamond-like carbon formed on the mixed layer,
In the mixed layer, the content of the tungsten carbide in the mixed layer decreases continuously or stepwise from the base layer side to the surface layer side, and the diamond-like carbon in the mixed layer decreases. A dimension measuring jig characterized by being a layer having a high content rate.   The dimension measuring jig according to claim 1, further comprising a curved surface portion on the surface of the base material. The hard film is brought into contact with SUJ2 hardened steel having a surface roughness Ra of 0.01 μm or less and a Vickers hardness Hv of 780 by applying a load with a maximum contact surface pressure of 0.5 GPa of Hertz. The specific wear amount of the hard film when the counterpart material is rotated for 30 minutes at a rotational speed of 05 m / s is less than 200 × 10 ⁻¹⁰ mm ³ / (N · m). The dimension measuring jig according to claim 1 or 2.   The dimension measurement jig according to claim 3, wherein the hard film has a sum of an average value of indentation hardness and a standard deviation value of 25 to 45 GPa.   The dimension measuring jig according to claim 3 or 4, wherein the hard film has a critical peel load in a scratch test of 50 N or more.   6. The surface layer according to claim 1, wherein the surface layer has an inclined layer portion whose hardness increases continuously or stepwise from the mixed layer side on the side adjacent to the mixed layer. The dimension measuring jig according to the item. The surface layer is a layer formed using an unbalanced magnetron sputtering apparatus using argon gas as a sputtering gas,
A graphite target and a hydrocarbon gas are used in combination as a carbon supply source, and the ratio of the introduction amount of the hydrocarbon gas to the introduction amount 100 of the argon gas into the device is 1 to 5, Under the condition that the degree of vacuum is 0.2 to 0.8 Pa and the bias voltage applied to the substrate is 70 to 150 V, carbon atoms generated from the carbon supply source are deposited on the mixed layer. The dimension measuring jig according to any one of claims 1 to 6, wherein the dimension measuring jig is a film.   The dimension measuring jig according to claim 7, wherein the hydrocarbon-based gas is methane gas.   9. The gradient layer portion of the surface layer is formed while raising a bias voltage applied to the substrate continuously or stepwise. Dimension measuring jig. The underlayer and the mixed layer are layers formed using an unbalanced magnetron sputtering apparatus using argon gas as a sputtering gas,
The mixed layer is formed in a continuous or stepwise manner while increasing the sputtering power applied to the graphite target serving as the carbon supply source and decreasing the power applied to the tungsten carbide target. The dimension measuring jig according to any one of claims 1 to 9, wherein the dimension measuring jig is characterized.   The film thickness of the hard film is 0.5 to 3 µm, and the ratio of the thickness of the surface layer to the film thickness of the hard film is 0.8 or less. The dimension measuring jig according to any one of 10.   The dimension measuring jig according to any one of claims 1 to 11, wherein the substrate is made of a cemented carbide material or an iron-based material.   13. The dimension measuring jig according to claim 12, wherein a nitride layer is formed by nitriding treatment on the surface on which the hard film is formed before the hard film is formed.   14. The dimension measuring jig according to claim 13, wherein the nitriding treatment is a plasma nitriding treatment, and the hardness of the surface after the nitriding treatment is Hv 1000 or more in terms of Vickers hardness.   The dimension measuring jig according to any one of claims 1 to 14, wherein the dimension measuring jig is a gauge, a surface plate, an exemplary part, or a member constituting them.   The dimension measuring jig according to claim 1, wherein the dimension measuring jig is a micrometer or a caliper.