JP5109320B2 - Sliding member - Google Patents

Description

  The present invention relates to a sliding member provided with a diamond-like carbon layer, and more specifically, the adhesion of the diamond-like carbon layer to the sliding member is increased, and the friction coefficient is lowered to provide excellent sliding properties. The present invention relates to a sliding member.

Conventionally, diamond-like carbon (DLC) is known to be excellent in hardness, wear resistance, solid lubricity, chemical stability, and the like. And the sliding member which provided this diamond-like carbon on the surface and improved abrasion resistance and sliding property is proposed (for example, refer to patent documents 1). In the sliding member described in Patent Document 1, a protective layer having a structure in which a Cr layer, a Cr-carbon layer composition gradient layer, a diamond-like carbon hardness gradient layer, and a hard diamond-like carbon are sequentially laminated is provided on the base material to protect the sliding member. The improvement of the adhesiveness of a layer and the improvement of slidability are aimed at.
JP 2004-10923 A

  However, diamond-like carbon has a problem that the internal residual stress is high and the adhesiveness is remarkably lowered under a high load condition. Even a sliding member having a structure as described in Patent Document 1 has a high load condition. Below, there was a problem that adhesiveness fell. In addition, hard diamond-like carbon materials with low hydrogen content that exhibit excellent wear resistance, wear resistance, seizure resistance, and durability in the atmosphere do not necessarily have a significant friction reducing effect in the presence of lubricating oil. . Even if such a diamond-like carbon material is applied to a lubricating oil containing an organic zinc compound used as an extreme pressure additive such as zinc dithiophosphate or molybdenum dithiocarbamate (MoDTC) used as a friction modifier. The surface of the diamond-like carbon is extremely stable and inactive, so that these additives do not function on the surface and the effect of reducing frictional wear is not sufficiently exhibited.

  The present invention has been made to solve the above-described problems, and has an object to provide a sliding member that exhibits high adhesion of diamond-like carbon to the sliding member and exhibits low friction. To do.

In order to achieve the above object, in the sliding member according to claim 1, a base material, an intermediate layer including a metal provided on the base material, and an intermediate layer provided on the intermediate layer, A low hardness comprising a first diamond-like carbon layer comprising a diamond-like carbon layer whose hardness increases continuously or stepwise as it leaves, and a diamond-like carbon layer having a predetermined hardness provided on the first diamond-like carbon layer. A second diamond-like layer in which a high-hardness layer composed of a diamond-like carbon layer having a higher hardness than the low-hardness layer is alternately laminated in this order from the upper side of the first diamond-like carbon layer in the order of a high-hardness layer and a low-hardness layer. A carbon layer, and the hydrogen content in the first diamond-like carbon layer and the second diamond-like carbon layer is 20 Ri t% to 50 at% der, the thickness of the first diamond-like carbon layer is 50Nm～700nm, the uppermost surface of the second diamond-like carbon layer, characterized that you have constructed from the low-hardness layer And

Further, the sliding member according to claim 2, in addition to the structure of the invention according to claim 1, the hydrogen content of the low-hardness layer of the outermost surface is characterized by a 20at% to 50 at%.

In the sliding member according to claim 3 , in addition to the configuration of the invention according to claim 1 or 2 , the lubricant applied to the outermost surface of the second diamond-like carbon layer includes an organic molybdenum compound and An organic zinc compound is included.

  In the sliding member according to claim 1, since the hydrogen content in the first diamond-like carbon layer and the second diamond-like carbon layer is 20 at% to 50 at%, stress is applied at the boundary with the substrate or the intermediate underlayer. Is suppressed, and a decrease in adhesion between the base material and the first diamond-like carbon layer and the second diamond-like carbon layer can be prevented. Also, a laminated periodic structure in which a high hardness layer and a low hardness layer are alternately laminated on a first diamond-like carbon layer (hereinafter also referred to as “graded layer”) whose hardness increases continuously or stepwise. By providing the second diamond-like carbon layer having, the internal stress on the surface layer side can be suppressed and the toughness can be improved. Furthermore, a film having a low wear coefficient and good slidability can be obtained.

Moreover, in the sliding member according to claim 1 , in addition to the effects of the above-described invention, a coating film having a low wear coefficient and good sliding property is obtained by setting the thickness of the first diamond-like carbon layer to 50 nm to 700 nm. I can do it.

Further, the sliding member according to claim 2, in addition to the effect of the invention according to claim 1, the adhesive material, the hydrogen content of the low-hardness layer of the outermost surface of the second diamond-like carbon layer is 20at % To 50 at%, the presence of a large amount of hydrogen groups on the surface of the diamond-like carbon layer reduces the shearing force, and the hydrogen groups with weak bonding strength fall off due to friction. In addition, the tribochemical reaction film can be formed and the function as a solid lubricant can be achieved by making the components contained in the organic molybdenum compound lubricant easy to adsorb, further improving the low friction and wear characteristics of diamond-like carbon. It can be improved.

In the sliding member according to claim 3 , in addition to the effect of the invention according to claim 1 or 2 , the lubricant applied to the outermost surface of the second diamond-like carbon layer includes an organic molybdenum compound and an organic Since it contains a zinc compound, a tribochemical reaction coating can be formed to exhibit the function as a solid lubricant, and the low friction and wear properties of diamond-like carbon can be further improved.

  Hereinafter, a sliding member according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a cross-sectional view of a sliding member 1 according to an embodiment of the present invention. The sliding member 1 of the present embodiment is provided with an intermediate layer 6 made of a chromium layer on a base material 5 made of a steel material (for example, chromium molybdenum steel, cemented carbide, etc.), and on the intermediate layer 6 A DLC multilayer film 10 made of diamond-like carbon (hereinafter also referred to as “DLC”) is provided.

  As shown in FIG. 1, the DLC multilayer film 10 is provided with an inclined layer 12 (corresponding to the first diamond-like carbon layer of the present invention) in which the hardness of the DLC is inclined in the intermediate layer 6 side. On the inclined layer 12, a laminated structure layer 11 of DLC films (corresponding to the second diamond-like carbon layer of the present invention) is provided. The DLC multilayer film 10 was produced by using a well-known UBM sputtering method (Unbalanced Magnetron sputtering process).

  Next, the inclined layer 12 will be described. As shown in FIG. 1, in the sliding member 1, an inclined layer 12 in which the hardness of DLC is inclined in the layer is provided on the intermediate layer 6 side. In this inclined layer 12, the intermediate layer 6 side has low hardness and the opposite side (laminated structure layer 11 side) has high hardness in one layer.

  Next, the laminated structure layer 11 constituting the DLC multilayer film 10 will be described. As shown in FIG. 1, the laminated structure layer 11 constituting the DLC multilayer film 10 is a DLC multilayer film composed of a plurality of layers in which DLC layers having different hardnesses are alternately stacked. That is, in the laminated structure layer 11 of the present embodiment, from the inclined layer 12 side, the high hardness layer 13, the low hardness layer 14, the high hardness layer 15, the low hardness layer 16, the high hardness layer 17, the low hardness layer 18, A hardness layer 19, a low hardness layer 20, a high hardness layer 21, and a low hardness layer 22 are laminated. That is, the laminated structure layer 11 is formed by stacking a pair of DLC high hardness layer and low hardness layer as one period (10 nm) until the film thickness of the laminated structure layer 11 is satisfied. In the above embodiment, the high hardness layer 13 to the low hardness layer 22 are exemplified, but the number of layers to be stacked may be larger or smaller than this, and the required film thickness of the laminated structure layer 11 may be used. The number of layers to be laminated is determined by the thicknesses of the high hardness layer and the low hardness layer.

  Next, with reference to the test result table shown in FIG. 2, the manufacturing method of the DLC multilayer film 10 and the results of the durability test of the sliding member 1 having the DLC multilayer film 10 manufactured by the manufacturing method will be described. . FIG. 2 shows the bias voltage, the generated DLC film thickness ratio, the DLC film thickness, the stacking cycle, the durability in the durability test (endurance time), the internal stress, and the samples 1 to 11 having the DLC film. It is a table | surface which shows the scratch contact | adhesion force in an indentation test result and a scratch contact | adherence test.

  As shown in the table of FIG. 2, for the sliding member 1 used in this test, a sample in which a DLC film is provided as a single layer on an intermediate layer 6 provided on a base material 5, and a laminated structure layer A total of 11 types are prepared: a sample provided only with a gradient layer, a sample provided with only a gradient layer, and a sample in which seven types of laminated structure layers are provided on the gradient layer with different film thickness ratios. A test was conducted.

In the durability test, an experiment was performed by sliding the balance shaft and the balance bearing, and the life of the sliding portion was measured. In this experiment, the balance shaft was rotated at 3300 rpm in an environment at a room temperature of 40 ° C., and the time (durability) until seizure occurred was measured. The PV value of the balance part is P = 1.4 MPa and V = 6.4 m / s. The grease applied to the balance shaft is DOS (dioctyl sebacate) as the base oil, 16% by weight of Li soap as the thickener, and 5% of ZnDTp (zinc dithiophosphate) and MoDTC (molybdenum dithiocarbamate) as additives. %It was used. The kinematic viscosity of DOS at 40 ° C. is 12 mm ² / s.

  In this endurance test, the balance shaft (balance shaft), balance bearing, and durability until seizure (endurance time) were set to 3500 hours as acceptable values. In general, it is known that an industrial sewing machine has an average working time of about 700 hours per year, with 3500 hours as an acceptance criterion. In that case, 3500 hours become an operation time for 5 years, and in a sewing machine having a durability of 3500 hours, lubricating oil may be supplied once every 5 years. Conventionally, grease replenishment every year has been required, but the lubricating oil supply cycle becomes very long once every five years, and the worker's lubricating oil supply operation can be greatly reduced. In addition, when the seizure life is 3500 hours or more, it corresponds to about 5 years of maintenance-free, and the general replacement life of industrial sewing machines is said to be 10 years. This is because the effect of reducing work is great.

  Next, the indentation test will be described. In this indentation test, a Rockwell C scale hardness measurement indenter was pushed into Samples 1 to 11, and the presence or absence of peeling around the indentation was observed with an optical microscope. As an indentation load, 150 kgf was applied.

  Next, the scratch test will be described. In the scratch test, a Rockwell C scale diamond indenter having a tip radius of 200 μm was moved in a certain direction by applying a vertical load to the samples 1-11. When the vertical load increases and exceeds the critical load, the coating in front of the indenter moves away, and the contact changes from the indenter and coating to the indenter and substrate, so the friction coefficient and stress components change and the scratch friction force increases. A critical load due to changing load, ie frictional force, is obtained. This critical load was quantitatively evaluated as the adhesion force.

  Hereinafter, with reference to the table shown in FIG. 2, the structure of the DLC film of the sample 1 (No: 1) to the sample 11 (No: 11) and the test result will be described. First, as Sample 1 (No: 1), as shown in FIG. 2, a DLC film having a single layer thickness of 1 μm was prepared by maintaining a bias voltage constant at 300 V in the UBM sputtering method. . The hydrogen content of the DLC film is 9.7 at%. And in this sample 1, the lifetime until seizure occurs is a durability of 900 hours, which is unacceptable. The internal stress of the DLC film of Sample 1 was 1.3 GPa. Moreover, in the indentation test, peeling occurred and the scratch adhesion was 65N.

  As sample 2 (No: 2), as shown in FIG. 2, a DLC film having a single layer thickness of 1 μm was prepared by maintaining the bias voltage constant at 300 V in the UBM sputtering method. . The average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. And in this sample 2, the lifetime until seizure occurs is a durability of 1500 hours, and it is unacceptable. And the internal stress of the DLC film of Sample 2 was 1.3 GPa. Moreover, in the indentation test, peeling occurred and the scratch adhesion was 65N.

  Sample 3 (No: 3) has a thickness of 1 μm as shown in FIG. 2 by applying a bias voltage of 0 V and 300 V alternately to form a DLC film in a laminated structure in the UBM sputtering method. It was created. The average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. In the UBM sputtering method, when the bias voltage is set to 0V, a DLC film having a low hardness is formed, and when the bias voltage is set to 300V, a DLC film having a high hardness is formed. Therefore, the intermediate layer 6 is alternately stacked with a DLC film having a high hardness, a DLC film having a low hardness, a DLC film having a high hardness, and a DLC film having a low hardness. The stacking period of the DLC film is 10 nm, and the surface layer has a hardness of 10 nm. It is a low DLC film. And in this sample 3, the lifetime until seizure occurs is a durability of 2000 hours and is unacceptable. The internal stress of the DLC film of Sample 3 was 0.3 GPa. In the indentation test, no peeling occurred and the scratch adhesion was 75N.

  As shown in FIG. 2, sample 4 (No: 4) is a UBM sputtering method in which a bias voltage is ramped up to 50 V to 300 V and applied, and the bias voltage is applied to one DLC film. The graded layer increases the hardness of the DLC film continuously or stepwise from the low hardness portion formed at 50V to the high hardness portion formed at a bias voltage of 300V. This inclined layer is a DLC film having a thickness of 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. In this sample 4, the lifetime until seizure is 1800 hours, and it is unacceptable. The internal stress of the DLC film of Sample 4 was 1.2 GPa. In the indentation test, a crack was generated and the scratch adhesion was 110 N.

  As sample 5 (No: 5), in the UBM sputtering method, the bias voltage is increased to 50 V to 300 V while increasing the voltage, and the bias voltage is formed at 50 V in one DLC film. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.01: 0.99, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 5, the lifetime until seizure occurs is 1800 hours, and it is unacceptable. And the internal stress of the DLC film of Sample 5 was 0.3 GPa. In the indentation test, no peeling occurred and the scratch adhesion was 75N.

  Further, as sample 6 (No: 6), in the UBM sputtering method, the bias voltage is increased while being inclined from 50 V to 300 V, and the bias voltage is formed at 50 V in one DLC film. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.05: 0.95, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 6, the life until seizure occurs is a durability of 3800 hours, which is acceptable. The internal stress of the DLC film of Sample 6 was 0.3 GPa. Further, in the indentation test, no peeling occurred and the scratch adhesion was 95N.

  As sample 7 (No: 7), in the UBM sputtering method, the bias voltage is inclined and increased to 50 V to 300 V and applied, and the bias voltage is formed at 50 V in one DLC film with low hardness. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.1: 0.9, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 7, the lifetime until seizure occurs is a durability of 4000 hours, which is acceptable. And the internal stress of the DLC film of Sample 7 was 0.3 GPa. Further, in the indentation test, no peeling occurred and the scratch adhesion was 95N.

  Further, as sample 8 (No: 8), in the UBM sputtering method, the bias voltage is increased while being inclined from 50 V to 300 V, and the bias voltage is formed in one DLC film at 50 V with low hardness. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.3: 0.7, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 8, the lifetime until seizure occurs is a durability of 4200 hours and is a pass. The internal stress of the DLC film of Sample 8 was 0.3 GPa. In the indentation test, no peeling occurred and the scratch adhesion was 105N.

  As sample 9 (No: 9), in UBM sputtering method, the bias voltage was increased to 50 V to 300 V while increasing the bias voltage, and the bias voltage was formed at 50 V in one DLC film with low hardness. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.5: 0.5, the total DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 9, the lifetime until seizure occurs is a durability of 4400 hours, and it passes. The internal stress of the DLC film of Sample 9 was 0.3 GPa. In the indentation test, no peeling occurred and the scratch adhesion was 105N.

  Further, as sample 10 (No: 10), in the UBM sputtering method, the bias voltage is increased to 50 V to 300 V while being increased and applied, and the bias voltage is formed at 50 V in one DLC film with low hardness. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.7: 0.3, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 10, the lifetime until seizure occurs is a durability of 4000 hours, which is acceptable. And the internal stress of the DLC film of Sample 10 was 0.5 GPa. Further, in the indentation test, no peeling occurred, and the scratch adhesion was 110N.

  Further, as sample 11 (No: 11), in the UBM sputtering method, the bias voltage is increased to 50 V to 300 V while being increased and applied, and the bias voltage is formed at 50 V in one DLC film with low hardness. In the UBM sputtering method, a bias voltage of 0 V and 300 V is applied alternately on a gradient layer that increases the hardness of the DLC film continuously or stepwise from a portion to a high hardness portion formed with a bias voltage of 300 V. Thus, a DLC film having a thickness of 1 μm was formed in a laminated structure. The thickness of the DLC film having the inclined layer + stacked structure is 1 μm, and the average hydrogen content up to 100 nm of the surface layer of the DLC film is 33 at%. Accordingly, the inclined layer 12 is formed on the intermediate layer 6, and the DLC film having high hardness, the DLC film having low hardness, the DLC film having high hardness, and the DLC film having low hardness are alternately stacked on the intermediate layer 6, and the surface layer has the hardness. It is a low DLC film. The film thickness ratio between the inclined layer and the laminated structure is 0.9: 0.1, the entire DLC film thickness is 1 μm, and the lamination period of the DLC film having the laminated structure is 10 nm. And in this sample 11, the lifetime until seizure occurs is 1800 hours, and it is unacceptable. And the internal stress of the DLC film of the sample 11 was 1.2 GPa. In the indentation test, a crack was generated and the scratch adhesion was 110 N.

  According to the endurance test results described above, since the samples 6 to 10 in which the thickness of the inclined layer 12 is 50 nm to 700 nm showed a durability of 3500 hours or more and passed, the thickness of the DLC inclined layer 12 was 50 nm to 700 nm. Was found to be preferred.

及びジアルキルジチオカルバミン酸モリブデン（ＭｏＤＴＣ）

を用いた。 Next, with reference to FIGS. 3 and 4, the relationship between the hydrogen content of the DLC film and the friction coefficient measured with a pin-on-disk friction and wear tester will be described. FIG. 3 is a table of friction coefficients measured with a DLC film pin-on-disk friction and wear tester with different hydrogen contents, and FIG. 4 is a graph of the table shown in FIG. In this pin-on-disk friction and wear test, a DLC film single layer coating is applied to a disk made of chromium molybdenum steel (SCM415 carburizing and quenching material) of φ55 mm, a lubricant is applied, and the tip polarity is applied to it. A spherical pin having a radius of 8 mm was pressed, and a frictional wear test was performed by changing the sliding speed for each hydrogen content at a room temperature of 30 ° C., a humidity of 50% and a test distance of 1000 m.
In addition, as an additive of lubricant (grease), zinc dialkyldithiophosphate (ZnDTP)

And molybdenum dialkyldithiocarbamate (MoDTC)

Was used.

  As shown in FIGS. 3 and 4, when the spherical pin has a surface pressure of 400 MPa and the sliding speed of the spherical pin is 2.0 m / sec, the hydrogen content of the DLC film is 9.7 at% and the friction coefficient is 0. .18, DLC film hydrogen content 19at% and friction coefficient 0.11, DLC film hydrogen content 33at% and friction coefficient 0.10, DLC film hydrogen content 45at% and friction coefficient The DLC film has a hydrogen content of 54 at% and a friction coefficient of 0.20.

  Further, as shown in FIGS. 3 and 4, when the surface pressure of the spherical pin is 400 MPa and the sliding speed of the spherical pin is 4.0 m / sec, the DLC film has a hydrogen content of 9.7 at% and a friction coefficient. The friction coefficient is 0.18, the hydrogen content of the DLC film is 19 at%, the friction coefficient is 0.11, the hydrogen content of the DLC film is 33 at%, the friction coefficient is 0.11, and the hydrogen content of the DLC film is 45 at%. The coefficient is 0.10, the hydrogen content of the DLC film is 54 at%, and the friction coefficient is 0.22.

  Therefore, from the above experimental results, the relationship between the hydrogen content of the DLC film and the friction coefficient is as large as 0.18 when the hydrogen content of the DLC film is 9.7 at%, and the hydrogen content of the DLC film. Is 54 at%, the friction coefficient is as large as 0.20 or more. As will be described later, when the hydrogen content is 9.7 at%, the coefficient of friction is increased because there is no adsorption of components derived from the additive of the lubricant (grease) on the DLC surface. Further, when the hydrogen content of the DLC film is 54 at%, the hardness of the DLC film becomes too low and wear progresses, so that the solid contact area increases and the friction coefficient increases. On the other hand, when the hydrogen content of the DLC film is 19 at%, the friction coefficient is 0.11, when the hydrogen content of the DLC film is 33 at%, the friction coefficient is 0.10 to 0.11, and the hydrogen content of the DLC film is When the amount is 45 at%, the friction coefficient is as small as 0.09 to 0.10. Therefore, if the hydrogen content of the DLC film is 19 at% to 45 at%, the friction coefficient is sufficiently small and good slidability can be realized.

  Next, the contact surface elemental analysis results will be described with reference to FIGS. This contact surface elemental analysis was carried out by using a DLC film of a 55 mm-diameter disk of chromium molybdenum steel (SCM415 carburized quenching material) subjected to the pin-on-disk friction and wear test, and a dialkyldithiophosphorus which is an additive for a lubricant (grease). Electron Probe Micro-Analysis (EPMA) shows how much zinc (Zn), molybdenum (Mo) and sulfur (S) derived from zinc oxide (ZnDTP) and molybdenum dialkyldithiocarbamate (MoDTC) are contained Was investigated. FIG. 5 is a table showing the hydrogen content of the DLC film and the content of the component derived from the additive of the lubricant (grease) to the DLC film, and FIG. 6 is a graph of the table shown in FIG. Is.

  As shown in FIGS. 5 and 6, when the hydrogen content of the DLC film is 9.7 at%, zinc is 0.00 at%, molybdenum is 0.00 at%, and sulfur is 0.00 at%. Further, when the hydrogen content of the DLC film is 19 at%, zinc is 0.45 at%, molybdenum is 0.09 at%, and sulfur is 0.04 at%. Further, when the hydrogen content of the DLC film is 33 at%, zinc is 0.77 at%, molybdenum is 0.15 at%, and sulfur is 0.12 at%. When the hydrogen content of the DLC film is 45 at%, zinc is 0.99 at%, molybdenum is 0.21 at%, and sulfur is 0.16 at%. When the hydrogen content of the DLC film is 54 at%, zinc is 1.03 at%, molybdenum is 0.24 at%, and sulfur is 0.17 at%.

  Accordingly, when the hydrogen content of the DLC film is 19 at% to 54 at%, the component derived from the additive of the lubricant (grease) can be detected from the DLC film, and the component derived from the additive is present on the DLC film surface. It is considered that a layered structure film is formed, and it is considered that a function as a solid lubricant is exhibited. Therefore, based on the contact surface elemental analysis results, the hydrogen content of the DLC film is preferably 19 at% to 54 at%. This is because, like a conventional iron part, a lubricant component (additive) is adsorbed and a tribo film is formed on the DLC film by sliding friction. As a result, the coefficient of friction under lubricating oil can be reduced. Moreover, it was found from the contact surface elemental analysis results that the lubricant preferably contains an organic molybdenum compound and an organic zinc compound. This is because when the hydrogen content of the DLC film is 19 at% to 54 at%, zinc, molybdenum and sulfur are added from zinc dialkyldithiophosphate (ZnDTP) and molybdenum dialkyldithiocarbamate (MoDTC), which are lubricant additives. This is because is taken into the DLC film.

  Next, with reference to FIG.7 and FIG.8, the relationship between hydrogen content and DLC film hardness is demonstrated. FIG. 7 is a table showing the relationship between the hydrogen content and the DLC film hardness, and FIG. 8 is a table graph of FIG. Here, the DLC film hardness was examined using an ultra-fine indentation hardness tester (nanoindentation tester) for a substrate in which a base material was a cemented carbide and a DLC film having each hydrogen content was formed thereon.

  As shown in FIGS. 7 and 8, when the hydrogen content of the DLC film is 9.7 at%, the hardness is 18 Gpa, and when the hydrogen content of the DLC film is 19 at%, the hardness is 16 Gpa. Yes, when the hydrogen content of the DLC film is 33 at%, the hardness is 15 Gpa, and when the hydrogen content of the DLC film is 45 at%, the hardness is 14 Gpa, and the hydrogen content of the DLC film is 54 at%. In the case of%, the hardness is 6 Gpa.

  From the above measurement results, it is understood that the case where the hydrogen content of the DLC film is 9.7 at% to 45 at% is preferable for preventing the decrease in the DLC film hardness. This is because, when hydrogen is contained, hydrogen atoms enter at the sites where covalent bonds are formed between carbon atoms, so that the hydrogen atoms are terminated and the covalent bond portions are reduced. Therefore, excessive hydrogen content causes an extreme decrease in hardness. Accordingly, when the hydrogen content exceeds 50 at%, the hardness becomes too low, the wear amount increases, the solid contact area increases, and the friction coefficient increases.

  As described above, according to the sliding member 1 according to the embodiment of the present invention, in the relationship between the hydrogen content of the DLC film and the friction coefficient measured by the pin-on-disk friction and wear tester, the hydrogen content of the DLC film It has been found that if the amount is 19 at% to 45 at%, the friction coefficient is sufficiently small and good slidability can be realized. Moreover, according to the contact surface elemental analysis result by an electron beam microanalyzer (EPMA), in order for the DLC film to adsorb the additive component of the lubricant, the hydrogen content of the DLC film is preferably 19 at% to 54 at%. It has been found. Further, in the DLC film hardness test using an ultra-indentation hardness tester, it was found that the hardness of 10 GPa or more can be realized when the hydrogen content of the DLC film is 9.7 at% to 45 at%. Therefore, in order to adsorb the additive component of the lubricant and suppress the hardness reduction of the DLC film, it is considered that the hydrogen content of the DLC film is preferably 20 at% to 50 at%.

  In addition, this invention is not restricted to the said embodiment, It can utilize for the friction reduction of various shafts, a bearing member, a sliding member, and other members which produce friction.

  The sliding member of the present invention is not limited to a shaft and a bearing, and can be applied to machines having various friction surfaces and sliding surfaces.

It is a schematic diagram of sectional drawing of the sliding member 1 which is one Embodiment of this invention. Bias voltage in the UBM sputtering method for samples 1 to 11, generated DLC film thickness ratio, DLC film thickness, stacking cycle, durability in durability test (endurance time), internal stress, indentation test result, scratch adhesion test 2 is a list showing scratch adhesion in It is a table | surface of the friction coefficient measured with the pin-on-disk type friction abrasion tester of the DLC film | membrane which changed hydrogen content. It is a graph of the friction coefficient measured with the pin-on-disk type friction and wear tester of the DLC film | membrane which changed hydrogen content. It is a table | surface which shows the hydrogen content of a DLC film, and the adsorption amount of the component derived from the additive of the lubrication agent (grease) to the said DLC film. It is a graph which shows the hydrogen content of a DLC film, and the adsorption amount of the component derived from the additive of the lubrication agent (grease) to the said DLC film. It is a table | surface which shows the relationship between the hydrogen content of a DLC film, and DLC film hardness. It is a graph which shows the relationship between the hydrogen content of a DLC film, and DLC film hardness.

DESCRIPTION OF SYMBOLS 1 Sliding member 5 Base material 6 Intermediate layer 10 DLC multilayer film 11 Laminated structure layer 12 Gradient layer 13 High hardness layer 14 Low hardness layer 15 High hardness layer 16 Low hardness layer 17 High hardness layer 18 Low hardness layer 19 High hardness layer 20 Low hardness layer 21 High hardness layer 22 Low hardness layer

Claims (3)

A substrate;
An intermediate layer comprising a metal provided on the substrate;
A first diamond-like carbon layer comprising a diamond-like carbon layer provided on the intermediate layer and having a hardness that increases continuously or stepwise as the distance from the intermediate layer increases;
The first diamond-like carbon layer includes a low-hardness layer made of a diamond-like carbon layer having a predetermined hardness and a high-hardness layer made of a diamond-like carbon layer having a higher hardness than the low-hardness layer. A second diamond-like carbon layer alternately stacked in the order of a high hardness layer and a low hardness layer from the upper side of the carbon layer;
The hydrogen content of the first diamond-like carbon layer and the second diamond-like carbon layer is Ri 20at% to 50 at% der,
The first diamond-like carbon layer has a thickness of 50 nm to 700 nm,
The uppermost surface of the second diamond-like carbon layer, a sliding member characterized that you have constructed from the low-hardness layer. The sliding member according to claim 1 , wherein the hydrogen content of the outermost low hardness layer is 20 at% to 50 at%. The sliding member according to claim 1 or 2 , wherein the lubricant applied to the outermost surface of the second diamond-like carbon layer contains an organic molybdenum compound and an organic zinc compound.

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