JP2007277663A - Sliding material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding material capable of improving wear resistance and adhesion with a counter material while further suppressing friction with the counter material. <P>SOLUTION: The sliding material comprises: a metallic layer 14 which is laminated on a substrate 12 and is joined to the substrate 12; a first layer 16 which is laminated on the metallic layer 14 and is a mixture of metal and carbon formed by grading composition ratio of metal and carbon by changing the composition ratio so as to successively increase carbon in the lamination direction; and a second layer 18 which is laminated on the first layer 16 and is a mixture of metal and carbon formed with a prescribed composition ratio of metal and carbon, wherein the first layer 16 and the second layer 18 are formed in a constant density of 2.2 g/cm<SP>3</SP>to 2.4 g/cm<SP>3</SP>, respectively. The metal is preferably Ti, Ta, Cr, Zr, Hf, V, Nb, Mo, W or Si. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sliding material, and in particular, a metal layer laminated on a base material and in close contact with the base material, laminated on the metal layer, and the composition ratio of the metal and carbon with respect to the lamination direction sequentially. The first layer in which the metal and carbon are mixed and formed by inclining the composition ratio of the metal and carbon by being changed so as to increase the carbon, and the first layer is laminated. The present invention relates to a sliding material having a second layer in which a metal and carbon are mixed by forming a predetermined composition ratio.

  Generally, a sliding material such as a connecting rod, a piston ring, or a sliding bearing used in a vehicle, particularly an automobile, is subjected to a surface treatment that coats a sliding surface with a hard ceramic material or the like. The sliding surface of the sliding material is covered with a ceramic material or the like, thereby improving the wear resistance, seizure resistance, impact resistance, or the like of the sliding surface.

  A hard ceramic material or the like is coated on the sliding surface of the sliding material by a physical vapor deposition method (PVD method) such as a sputtering method or an ion plating method, a chemical vapor deposition method (CVD method), or the like. Examples of such a ceramic material coating include a TiC coating and a TiN coating that are titanium coatings, a CrN coating that is a chromium coating, and diamond-like carbon (diamond-like carbon). A hard coating such as a DLC) coating is used.

  Here, in Patent Document 1, in a sliding member including a base material and a protective film formed on the surface of the base material, the protective film includes a metal layer and a metal-carbon composition formed on the metal layer. A sliding member is shown that includes a graded layer and a diamond-like carbon layer formed on the metal-carbon composition graded layer and having a hardness change region in which the hardness increases as the distance from the metal-carbon composition graded layer increases.

JP 2004-10923 A

  The above-mentioned diamond-like carbon layer achieves low friction by self-lubricating by sliding with a mating member, and polishing down into a layer due to the graphite structure that is the fine structure of the diamond-like carbon layer. Therefore, the wear resistance in the sliding material may not be obtained sufficiently. In addition, when the film has a thin multilayer structure, the presence of a layer having no graphite structure may increase the sliding resistance with the counterpart material and increase the friction coefficient.

  Therefore, an object of the present invention is to laminate a metal layer that is laminated on a base material and is in close contact with the base material, and a metal layer, and to increase the composition ratio of the metal and the carbon in order with respect to the lamination direction. The first layer in which the metal and carbon are mixed and formed by inclining the composition ratio of the metal and carbon, and the first layer is laminated, and the metal and carbon have a predetermined composition ratio. In the sliding material having the second layer in which the metal and the carbon are mixed, the friction with the counterpart material is further suppressed to further improve the wear resistance and adhesion.

The sliding material according to the present invention is laminated on a base material, and is laminated on the metal layer, and is laminated on the metal layer, and the composition ratio of the metal and the carbon is sequentially changed with respect to the lamination direction. By changing so as to increase, the first layer in which the composition ratio of the metal and carbon is inclined and the metal and carbon are mixed, the first layer is laminated, and the metal and carbon have a predetermined composition. A sliding material having a second layer in which metal and carbon are mixed by forming as a ratio, and the first layer and the second layer have a density of 2.2 g / cm ³ to 2.4 g / cm ^3. It is characterized by being formed constant.

  In the sliding material according to the present invention, the metal is preferably Ti, Ta, Cr, Zr, Hf, V, Nb, Mo, W, or Si.

  In the sliding material according to the present invention, the first layer has a composition ratio of metal and carbon such that carbon is increased in order from a carbon / metal atomic ratio of 1.7 to 10 with respect to the stacking direction. Therefore, it is preferable that the composition ratio of the metal and carbon is inclined.

  In the sliding material according to the present invention, the second layer preferably has a predetermined composition ratio of metal to carbon of 10 to 15 in terms of a carbon / metal atomic ratio.

  In the sliding material according to the present invention, the thickness of the second layer is preferably within 10% of the total thickness of the metal layer, the first layer, and the second layer.

  In the sliding material according to the present invention, the friction coefficient is preferably 0.05 or less.

  According to the above sliding material, it is possible to further suppress the friction with the counterpart material and further improve the wear resistance and adhesion.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of the sliding member 10. The sliding material 10 is laminated on the base material 12, and is laminated on the metal layer 14 that is in close contact with the base material 12, and the composition ratio of the metal and carbon is sequentially changed to carbon in the laminating direction. The first layer 16 in which the metal and carbon are mixed and formed by inclining the composition ratio of the metal and carbon, and the first layer 16 is laminated, and the metal and carbon are combined. It has the 2nd layer 18 in which the metal and carbon mixed by forming as a predetermined composition ratio.

  For the substrate 12, structural carbon steel, structural alloy steel, or the like can be used. As the structural alloy steel, chrome molybdenum steel, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, manganese steel, manganese chrome steel, aluminum chrome molybdenum steel, or the like can be used. These structural carbon steels and structural alloy steels are preferably used with a predetermined hardness and strength by performing a heat treatment such as quenching and tempering. Of course, depending on other conditions, the base material 12 is not limited to these materials, and cemented carbide, alloy tool steel, stainless steel, aluminum alloy and the like can be used.

  The metal layer 14 is laminated on the base material 12 such as the structural carbon steel or structural alloy steel, and is in close contact with the base material 12. The metal layer 14 has a function of activating the surface of the base material 12 and a function of increasing the adhesion with the interface of the base material 12 by a throwing effect.

  The metal constituting the metal layer 14 is made of Ti, Ta, Cr, Zr, Hf, V, Nb, Mo, W metals such as IV-B group, VB group and VI-B group metals or Si. Can do. The metal constituting the metal layer 14 is preferably Ti, Ta, or Cr. The metal constituting the metal layer 14 is more preferably Ti because the material is low cost. Further, for the metal constituting the metal layer 14, elements such as IV-A group, VA group, VI-A group, etc. may be used.

  This is because these metals easily form a metal carbide, metal nitride, metal oxide, or the like by chemically reacting with carbon, nitrogen or oxygen contained in the substrate 12. And the adhesiveness of the base material 12 and the metal layer 14 can be improved by forming the metal carbide, metal nitride, or metal oxide of the said element in the interface of the base material 12 and the metal layer 14. . Of course, depending on other conditions, the metal constituting the metal layer 14 is not limited to these elements.

  The metal layer 14 is laminated on the substrate 12 with a film thickness of several tens of nm. The film thickness of the metal layer 14 is 10 nm or more and 30 nm or less, for example. Of course, the film thickness of the metal layer 14 is not limited to the above film thickness range. Further, depending on other conditions, a metal nitride layer such as TiN, a metal carbide such as TiC, and a metal carbonitride layer such as TiCN can be provided in addition to or instead of the metal layer 14. This is because TiN, TiC, TiCN, and the like are hard materials, so that the hardness of the film can be further increased by adding a hard layer, and the wear resistance of the film is further improved.

  The first layer 16 is laminated on the metal layer 14, and the composition ratio of the metal and carbon is inclined by changing the composition ratio of the metal and carbon sequentially with increasing carbon in the lamination direction. It is a layer in which the metal and carbon formed are mixed. The first layer 16 has a function of relaxing the internal stress of the film and a function of suppressing wear. The first layer 16 is formed by gradually changing the composition ratio of the metal and carbon with respect to the stacking direction so as to increase the amount of carbon, thereby gradually softening the film with respect to the stacking direction. Can be relaxed. This is because as the amount of metal increases, the bond between the metal and carbon increases and the hardness of the coating increases.

  The first layer 16 has a function as a load backup layer of the second layer 18 because the first layer 16 has high hardness on the metal layer 14 side and gradually softens in the stacking direction. Therefore, even when the second layer 18 is worn, further progress of wear can be suppressed. In addition, since the first layer 16 has a large proportion of metal on the metal layer 14 side, the adhesion with the metal layer 14 can be further improved.

  The first layer 16 is formed by changing the composition ratio of metal and carbon from 1.7 to 10 in a carbon / metal atomic ratio with respect to the stacking direction so that the amount of carbon increases in order. And the composition ratio is preferably inclined. The metal / carbon composition ratio on the metal layer 14 side is set to 1.7 in terms of the carbon / metal atomic ratio. If the carbon / metal atomic ratio is less than 1.7, the metal and carbon undergo a chemical reaction to form a metal. This is because when the carbide is formed, a crystalline layer made of the metal carbide is generated at the interface between the first layer 16 and the metal layer 14 and may become a starting point of peeling. The reason why the metal / carbon composition ratio on the second layer 18 side is 10 in terms of the carbon / metal atomic ratio is that when the carbon / metal atomic ratio is greater than 10, the adhesion decreases. Of course, depending on other conditions, the composition ratio of metal to carbon is not limited to the range of the composition ratio.

It is preferable that the density of the first layer 16 and the second layer 18 is constant between 2.2 g / cm ³ and 2.4 g / cm ³ . Thus, since the density of the first layer 16 is constant from 2.2 g / cm ³ to 2.4 g / cm ³ , cracking and peeling due to the difference in density in the film can be suppressed, Abrasion resistance and adhesion can be improved. Of course, depending on other conditions, the density is not limited to the above range. Moreover, it is preferable that the film thickness of the 1st layer 16 shall be 1 micrometer or more and 3 micrometers or less. Of course, the film thickness of the first layer 16 is not limited to the range of the film thickness.

  As the metal of the first layer 16, Ti, Ta, Cr, etc., which are the metals described above, can be used. The metal of the first layer 16 is preferably the same metal as the metal layer 14. For example, when titanium is used for the metal layer 14, titanium is used for the metal of the first layer 16. Of course, depending on other conditions, different metals can be used for the metal of the first layer 16 and the metal of the metal layer 14.

  The second layer 18 is a layer in which the metal and carbon are mixed by being stacked on the first layer 16 and forming the metal and carbon in a predetermined composition ratio. The second layer 18 has a function of suppressing friction between the mating material and the sliding material 10 when the sliding material 10 slides on the mating material and a metal-oxygen layer is formed on the mating material. . For example, when titanium is used as the metal, a Ti—O layer is formed on the counterpart material. The second layer 18 can function as an initial conforming layer when the sliding material 10 and the counterpart material slide.

  The second layer 18 preferably has a predetermined composition ratio of metal to carbon of 10 to 15 in terms of a carbon / metal atomic ratio. More preferably, the carbon / metal atomic ratio is 10 or more and 12 or less. The reason why the carbon / metal atomic ratio is 10 or more and 15 or less is that the hardness of the film can be reduced by increasing the proportion of carbon as compared with the first layer 16. Moreover, it is because a friction coefficient can be lowered | hung by making the ratio of carbon larger than the 1st layer 16, for example, can be 0.05 or less. Then, by laminating the second layer 18 having a lower hardness than the first layer 16 on the first layer 16, the second layer 18 can function as a familiar layer at the initial stage of sliding. This is because it is effective that the soft layer is thinly present on the hard base layer. Of course, depending on other conditions, the predetermined composition ratio between the metal and the carbon is not limited to the above range.

  The thickness of the second layer 18 is preferably within 10% of the total thickness of the metal layer 14, the first layer 16, and the second layer 18. The film thickness of the second layer 18 is within 10% of the total film thickness of the metal layer 14, the first layer 16, and the second layer 18 when the sliding material 10 slides with the counterpart material. This is because the metal-oxygen layer is formed on the counterpart material and the film thickness is sufficient to suppress the friction between the sliding material 10 and the counterpart material. When the total thickness of the metal layer 14, the first layer 16, and the second layer 18 is 2 μm, the thickness of the second layer 18 is 0.2 μm. Of course, depending on other conditions, the film thickness of the second layer 18 is not limited to the above range of film thickness.

  As the metal of the second layer 18, Ti, Ta, Cr, etc., which are the metals described above, can be used. The metal of the second layer 18 is preferably the same metal as the metal of the first layer 16 and the metal of the metal layer 14. For example, when titanium is used for the metal of the first layer 16 and the metal layer 14, titanium is used for the metal of the second layer 18. Of course, depending on other conditions, a metal different from the metal of the second layer 18 and the metal of the first layer 16 and the metal of the metal layer 14 can be used.

  Below, the manufacturing method of the sliding material 10 in the said structure is demonstrated. FIG. 2 is a flowchart showing a method for manufacturing the sliding member 10. The manufacturing method of the sliding member 10 includes a base material preparation step (S10), a metal layer formation step (S12), a first layer formation step (S14), and a second layer formation step (S16). .

  The base material preparation step (S10) is a step of preparing the base material 12 in the sliding material 10 by pretreatment or the like. The substrate 12 is first polished with an abrasive or the like so that the surface of the substrate 12 has a predetermined surface roughness. The ground substrate 12 is prepared by degreasing and cleaning with an organic solvent such as acetone by ultrasonic cleaning or the like.

  In the prepared base material 12, the metal layer 14, the first layer 16, and the second layer 18 are laminated by an arc ion plating method (AIP method). Of course, depending on other conditions, it can be laminated by other methods.

  First, the arc ion plating method will be described. FIG. 3 is a schematic diagram showing a film forming method in the arc ion plating method. When a metal material such as titanium is sublimated by arc discharge, a hydrocarbon gas such as acetylene is introduced, the metal and carbon are ionized by high energy density plasma generated by the discharge, and the substrate 12 has a negative bias voltage. , The metal and carbon ions can be attracted to the substrate 12 and laminated. Since the arc ion plating method has a higher film formation rate than the case where a film is formed by a sputtering method using a solid carbon target, productivity can be improved and manufacturing cost can be reduced.

  An arc ion plating apparatus used in the arc ion plating method includes an arc power source, a bias power source for applying a negative bias voltage to a base material 12 that forms a film placed in a vacuum chamber, carbon, Introducing a hydrocarbon gas, which is a raw material, and a discharge gas such as nitrogen, argon, etc., and an arc power source is provided with a metal target, which is a metal raw material. The metal target acts as a cathode of an arc power source, and metal is sublimated and ionized from the metal target by arc discharge with the anode. With the above configuration, in a hydrocarbon gas atmosphere introduced from the introduction port, the metal target is sublimated by arc discharge and the metal and carbon are ionized to form a composite film of metal and carbon mixed on the base material 12. A diamond-like carbon film can be formed.

  Also, in the arc ion plating system, by controlling the metal arc current, the type and flow rate of hydrocarbon gas, bias voltage, etc., the metal film or the metal and carbon mixed with different composition ratios of the metal and carbon are mixed. It is possible to form a diamond-like carbon film composited with a metal which is a coated film. Further, by changing the composition ratio of metal and carbon to form a film, the hardness, friction coefficient, adhesion, density, etc. of the film can be controlled.

  As the hydrocarbon gas, methane, ethylene, acetylene, benzene, or the like can be used. Moreover, it is preferable to use acetylene gas for hydrocarbon gas. Of course, other hydrocarbon gases can be used depending on other conditions. The flow rate of the hydrocarbon gas is preferably 100 sccm or more and 300 sccm or less. Of course, the flow rate of the hydrocarbon gas is not limited to this range.

  The relationship between the composition ratio of metal and carbon, hardness, and friction coefficient in the film will be described. FIG. 4 is a diagram showing the relationship between the C / Ti atomic ratio, which is the composition ratio between titanium and carbon in the coating, hardness, and friction coefficient when titanium is used as the metal. In FIG. 4, the vertical axis represents the hardness of the film and the friction coefficient μ, and the horizontal axis represents the C / Ti atomic ratio which is the composition ratio of titanium and carbon in the film. Each data shown in FIG. 4 is obtained by forming a film having a different C / Ti atomic ratio by changing a metal arc current, a flow rate of hydrocarbon gas, a bias voltage, or the like using an arc ion plating apparatus. Data.

  In FIG. 4, the smaller the C / Ti atomic ratio of the film, the larger the hardness and the friction coefficient of the film, and the larger the C / Ti atomic ratio of the film, the smaller the film hardness and the friction coefficient. Then, the hardness and friction coefficient of the film decrease in a substantially linear manner in proportion to the increase in the C / Ti atomic ratio. This is because, as the C / Ti atomic ratio is smaller, the proportion of titanium increases, and the bond between titanium and carbon increases. Thus, the hardness and the friction coefficient of the film can be controlled by changing the composition ratio between the metal and carbon.

  Next, the relationship between the composition ratio between the metal and carbon in the coating and the adhesion will be described. FIG. 5 is a diagram showing the relationship between the C / Ti atomic ratio, which is the composition ratio between titanium and carbon in the coating, and the adhesion when titanium is used as the metal. In FIG. 5, the vertical axis represents the adhesion of the film, and the horizontal axis represents the C / Ti atomic ratio, which is the composition ratio of titanium and carbon in the film. Each data shown in FIG. 5 is obtained by forming a film having a different C / Ti atomic ratio by changing a metal arc current, a flow rate of hydrocarbon gas, a bias voltage, or the like using an arc ion plating apparatus. Data. As shown in FIG. 5, the adhesion of the film can be further increased by reducing the C / Ti atomic ratio.

  Furthermore, the relationship between the composition ratio of metal and carbon in the film, the density, and the bias voltage will be described. FIG. 6 is a diagram showing the relationship between the C / Ti atomic ratio, which is the composition ratio between titanium and carbon, the density, and the bias voltage when titanium is used as the metal. In FIG. 6, the vertical axis represents the density of the film, and the horizontal axis represents the C / Ti atomic ratio, which is the composition ratio of titanium and carbon in the film. Each data shown in FIG. 6 shows that an arc ion plating apparatus is used to change the bias voltage to 100V, 200V, 400V and 800V to form films with different C / Ti atomic ratios at each bias voltage. Is the data acquired.

  As shown in FIG. 6, when a constant bias voltage is applied, the density of the film decreases as the C / Ti atomic ratio increases. This is because the ratio of carbon (graphite) in the film increases. Further, when the C / Ti atomic ratio is constant, the coating density increases as the bias voltage increases. The reason why the density increases as the bias voltage increases is that the incident energy of each atom in carbon or titanium increases. By sequentially changing the bias voltage and controlling the film, it is possible to form the film while changing the C / Ti atomic ratio at a constant film density. Thus, the density of the film can be controlled by the bias voltage.

  Next, a metal layer forming step (S12), which is a step of laminating the metal layer 14, the first layer 16, and the second layer 18 on the substrate 12 by the arc ion plating method (AIP method), The first layer forming step (S14) and the second layer forming step (S16) will be described.

  The metal layer forming step (S12) is a step of forming the metal layer 14 on the pretreated base material 12. First, the pretreated substrate 12 is set in a vacuum chamber of an arc ion plating apparatus. The inside of the vacuum chamber is evacuated by a vacuum pump or the like until a predetermined degree of vacuum is reached. After the inside of the vacuum chamber reaches a predetermined degree of vacuum, the pretreated base material 12 is preheated for a predetermined time at a predetermined heater temperature.

  The metal layer 14 is laminated by performing ion bombardment on the pretreated substrate 12 using a metal target. The ion bombardment can be performed by controlling the metal arc current, the bias voltage, and the like. The metal layer 14 is formed with a film thickness of several tens of nm or less, for example, a film thickness of 10 nm or more and 30 nm or less by ion bombarding the pretreated substrate 12 for a predetermined time.

  In the first layer forming step (S14), by changing the composition ratio of the metal and carbon to the base material 12 on which the metal layer 14 is laminated in such a manner that the amount of carbon is increased sequentially with respect to the lamination direction, This is a step of forming the first layer 16 in which the metal and carbon are formed by inclining the composition ratio of the metal and carbon. The first layer 16 is formed by controlling the metal arc current, the type and flow rate of hydrocarbon gas, the bias voltage, and the like. As the hydrocarbon gas, acetylene gas is preferably used.

  The first layer 16 controls the metal arc current, the type and flow rate of the hydrocarbon gas, the bias voltage, and the like so that the composition ratio of the metal and carbon is the carbon / metal atomic ratio with respect to the stacking direction. It is preferable that the composition ratio of metal to carbon is inclined from 1.7 to 10. Thereby, as shown in FIG.4 and FIG.5, the 1st layer 16 can have predetermined | prescribed hardness, a predetermined | prescribed friction coefficient, and predetermined | prescribed adhesiveness.

The first layer 16 can form a film while changing the C / Ti atomic ratio at a constant film density by sequentially controlling the bias voltage. In the case where the C / Ti atomic ratio of the first layer 16 is changed from 1.7 to 12, the density is increased to 2.2 V / g by increasing the bias voltage sequentially from 100 V to 400 V as shown in FIG. in the cm ³ or more 2.4 g / cm ³ or less of a substantially constant, the C / Ti atomic ratio may vary from 1.7 to 12.

  In the second layer forming step (S16), the metal and carbon are mixed at a predetermined composition ratio on the base material 12 on which the metal layer 14 and the first layer 16 are laminated. This is a step of forming the two layers 18. The second layer 18 is formed by controlling the metal arc current, the type and flow rate of hydrocarbon gas, the bias voltage, and the like. As the hydrocarbon gas, it is preferable to use acetylene gas as in the formation of the first layer 16.

  The second layer 18 controls the metal arc current, the type and flow rate of hydrocarbon gas, the bias voltage, etc., so that the predetermined composition ratio of metal to carbon is 10 to 15 in terms of carbon / metal atomic ratio. It is preferable to be formed as follows. Thereby, as shown in FIG.4 and FIG.5, the 2nd layer 16 can be made to have predetermined | prescribed hardness, a predetermined | prescribed friction coefficient, and predetermined | prescribed adhesiveness. A bias voltage for forming the second layer 18 is formed by applying a constant voltage. Of course, depending on other conditions, as with the formation of the first layer 16, the film may be formed by changing the bias voltage.

  After the second layer forming step, a step of removing projections formed by adhesion of molten particles (droplets) to the surface of the second layer 18 can be provided. For removing such protrusions, a water jet, sand paper (about # 500), paper wrap, aero wrap, or the like can be used. The concave portion on the surface of the second layer 18 formed after removing the protrusions functions as an oil reservoir when oil-lubricated, for example. 10 can be oil-lubricated.

  According to the said structure, friction with a counterpart material can further be suppressed and abrasion resistance and adhesiveness can be improved more.

  According to the above configuration, since the metal layer 14, the first layer 16, and the second layer 18 are formed by the arc ion plating method, the film formation rate can be made faster than the sputtering method. Thereby, the productivity of the sliding member 10 can be further improved, and the production cost can be further reduced.

  According to the said structure, the hardness of a membrane | film | coat, a friction coefficient, adhesiveness, a density, etc. can be controlled by managing the composition ratio in a metal and carbon. Further, by increasing the flow rates of the metal arc current and acetylene gas and further reducing the coating time, the productivity of the sliding material 10 can be further improved and the production cost can be further reduced.

  The sliding member 10 in Example 1 having the above-described configuration was manufactured. FIG. 7 is a diagram illustrating a configuration of the sliding member 10 according to the first embodiment. As the substrate 12, SCM415 which is chromium molybdenum steel was used. The base material 12 was carburized and then subjected to heat treatment such as quenching and tempering, and the hardness was set to HV800 in terms of Vickers hardness. The heat-treated base material 12 was diamond-wrapped and mirror-finished with a surface roughness of 0.02Ra. Further, the mirror-finished substrate 12 was ultrasonically washed with acetone for 5 minutes and degreased and washed.

The cleaned base material 12 was set in a vacuum chamber of an arc ion plating apparatus and evacuated to a base pressure of 2 × 10 ⁻³ Pa. The cleaned substrate 12 was preheated at a heater temperature of 500 ° C. for 30 minutes.

  The cleaned base material 12 was subjected to ion bombardment, and a Ti metal layer 14 was laminated on the base material 12. The ion bombardment was performed with a Ti arc current of 80 A, a bias voltage of 600 V, and a treatment time of 5 minutes. Then, several tens of nm of titanium was laminated on the substrate 12 by ion bombardment.

  Next, the first layer 16 and the second layer 18 in which titanium and carbon were mixed were formed on the titanium layer. FIG. 8 is a diagram showing film forming conditions for the first layer 16 and the second layer 18 in which titanium and carbon are mixed. The Ti arc current was constant at 60A. The flow rate of the acetylene gas used as the hydrocarbon gas was controlled in proportion to the film formation time from 50 ml / min to 300 ml / min. The bias voltage was controlled from 100 V to 400 V in proportion to the film formation time. The film formation time for the first layer 16 and the second layer 18 was 60 minutes in total.

The sliding material in Comparative Example 1 will be described. FIG. 9 is a diagram illustrating the configuration of the sliding member in Comparative Example 1. Comparative Example 1 is laminated on a base material made of chromium molybdenum steel SCM415, and is laminated on the titanium layer and the titanium layer, and the composition ratio of titanium and carbon is set to By changing the Ti atomic ratio from 1.7 to 10 in order so as to increase the carbon, the composition gradient layer in which titanium and carbon are mixed and formed by inclining the composition ratio of titanium and carbon. It is a configured sliding material. The layer in which titanium and carbon were mixed was formed by inclining the composition ratio of titanium and carbon at a density of 2.2 g / cm ³ or more and 2.4 g / cm ³ or less. Therefore, in Comparative Example 1, the second layer 18 is not stacked with respect to the configuration of Example 1. The substrate pretreatment, the titanium layer forming method, and the composition gradient layer forming method in which titanium and carbon were mixed in Comparative Example 1 were performed in the same manner as in Example 1.

The sliding material in Comparative Example 2 will be described. FIG. 10 is a diagram illustrating the configuration of the sliding member in Comparative Example 2. Comparative Example 2 is laminated on a base material that is chromium molybdenum steel SCM415, and is laminated on a titanium layer that is in close contact with the base material, and is laminated on the titanium layer. A composition gradient layer in which titanium and carbon are formed by inclining the composition ratio of titanium and carbon by sequentially changing the metal atomic ratio from 1.7 to 10 so as to increase carbon. It is a sliding material having a layer in which titanium and carbon are mixed by being laminated on a composition gradient layer and forming the composition ratio of titanium and carbon as a carbon / metal atomic ratio of 10 or more and 12 or less. In Comparative Example 2, the composition ratio of titanium and carbon in the formation of the composition gradient layer is inclined with respect to the configuration of Example 1 without making the density constant from 2.2 g / cm ³ to 2.4 g / cm ^3. Formed. The substrate pretreatment and the titanium layer forming method in Comparative Example 2 were performed in the same manner as in Example 1. Other composition gradient layers in which titanium and carbon were mixed were formed by a predetermined bias voltage or the like.

  For the sliding materials in Example 1 and Comparative Examples 1 and 2, the friction coefficient, the amount of wear, and the adhesion strength were measured. The coefficient of friction and the amount of wear were measured by a ball-on-disk friction and wear test. The adhesion strength was determined by a scratch adhesion test.

  A test method for the ball-on-disk friction and wear test will be described. FIG. 11 is a schematic diagram showing an outline of a ball-on-disk friction and wear test. A ball-shaped jig that slides with a disk-shaped test piece simulating a sliding material is placed on the test piece. The ball-shaped jig and the test piece slide as the ball-shaped jig moves on the surface of the test piece at a predetermined sliding speed. Here, bearing steel SUJ2 in JIS G4805, which is an Fe-based material, was used for the ball-shaped jig. The test conditions for the ball-on-disk friction and wear test are as follows: the load applied to the test piece is 10 N, the contact stress of the contact surface between the ball-shaped jig and the test piece is 1300 MPa, the sliding speed is 0.3 m / s, and the distance is The test was conducted with 2 km and dry lubrication.

  A test method for the scratch adhesion test will be described. FIG. 12 is a schematic diagram showing an outline of the scratch adhesion test. The scratch adhesion test is a test method conforming to the Japan Society of Mechanical Engineers standards with a maximum vertical load of 200N. After pressing the diamond indenter onto the test piece with a predetermined load, the test piece is moved while a load is applied at a predetermined load load speed, and the adhesiveness is applied by the load at which the film coated on the test piece is peeled off. This is a test method for evaluating Here, the test conditions of the scratch adhesion test were a diamond indenter tip radius of 0.2 mm and a load loading speed of 10 N / mm.

  Next, the test results of the ball-on-disk friction and wear test and the scratch adhesion test will be described for the sliding materials in Example 1 and Comparative Examples 1 and 2. Table 1 shows the results of the coefficient of friction, the amount of wear, and the adhesion strength measured by the ball-on-disk friction and abrasion test and the scratch adhesion test.

  The coefficient of friction was 0.04 in Example 1, 0.2 in Comparative Example 1, and 0.04 in Comparative Example 2. In Comparative Example 1, seizure occurred during the test. The reason why Example 1 and Comparative Example 2 showed excellent frictional characteristics is that the second layer has a low friction layer having a C / Ti atomic ratio of 10 to 12, and the like.

  The amount of wear was 0.15 μm in Example 1 and 0.2 μm in Comparative Example 2. Note that Comparative Example 1 could not be measured because seizure occurred.

The adhesion strength was 50N in Example 1, 50N in Comparative Example 1, and 30N in Comparative Example 2. In Comparative Example 2, cracking and peeling were observed in the coating layer. The adhesion strength of Comparative Example 2 is low because the density is 2.2 g / cm ³ to 2.4 g in the composition gradient layer in which titanium and carbon are formed by inclining the composition ratio of titanium and carbon. This is because, for example, / cm ³ is not inclined but is inclined.

In embodiment which concerns on this invention, it is sectional drawing which shows the structure of the sliding material 10. FIG. In embodiment which concerns on this invention, it is a flowchart which shows the manufacturing method of the sliding material 10. In embodiment which concerns on this invention, it is a schematic diagram which shows the formation method of the membrane | film | coat in the arc ion plating method. In embodiment which concerns on this invention, when titanium is used for a metal, it is a figure which shows the relationship between C / Ti atomic ratio which is a composition ratio of the titanium and carbon in a film | membrane, hardness, and a friction coefficient. In embodiment which concerns on this invention, when titanium is used for a metal, it is a figure which shows the relationship between C / Ti atomic ratio which is a composition ratio of titanium and carbon in a film | membrane, and adhesiveness. In embodiment which concerns on this invention, when titanium is used for a metal, it is a figure which shows the relationship between C / Ti atomic ratio which is a composition ratio in titanium and carbon in a film | membrane, a density, and a bias voltage. In embodiment which concerns on this invention, it is a figure which shows the structure of the sliding material 10 in Example 1. FIG. In embodiment which concerns on this invention, it is a figure which shows the film-forming conditions of the 1st layer 16 and the 2nd layer 18 which titanium and carbon mixed. In embodiment which concerns on this invention, it is a figure which shows the structure of the sliding material in the comparative example 1. FIG. In embodiment which concerns on this invention, it is a figure which shows the structure of the sliding material in the comparative example 2. FIG. In embodiment which concerns on this invention, it is a schematic diagram which shows the outline | summary of a ball-on-disk friction wear test. In embodiment which concerns on this invention, it is a schematic diagram which shows the outline | summary of a scratch adhesion test.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Sliding material, 12 base material, 14 metal layer, 16 1st layer, 18 2nd layer, S10 base material preparation process, S12 metal layer formation process, S14 1st layer formation process, S16 2nd layer formation process.

Claims (6)

A metal layer laminated to the base material and in close contact with the base material;
A metal layer formed on a metal layer, and the composition ratio of the metal and carbon is changed in such a manner that the composition ratio of the metal and the carbon is gradually increased with respect to the stacking direction so as to increase the amount of carbon. A first layer mixed with carbon;
A second layer in which the metal and the carbon are mixed by being stacked on the first layer and forming the metal and the carbon at a predetermined composition ratio;
A sliding material having
The first layer and the second layer are formed with a constant density of 2.2 g / cm ³ to 2.4 g / cm ³ . The sliding material according to claim 1,
A sliding material characterized in that the metal is Ti, Ta, Cr, Zr, Hf, V, Nb, Mo, W or Si. The sliding material according to claim 1 or 2,
The first layer is formed by changing the composition ratio of metal and carbon from 1.7 to 10 in a carbon / metal atomic ratio with respect to the stacking direction so that the amount of carbon increases in order. A sliding material characterized in that it is formed by inclining the composition ratio. The sliding material according to any one of claims 1 to 3,
The second layer has a predetermined composition ratio between metal and carbon of 10 to 15 in terms of carbon / metal atomic ratio. The sliding material according to any one of claims 1 to 4,
A sliding material characterized in that the thickness of the second layer is within 10% of the total thickness of the metal layer, the first layer, and the second layer. The sliding material according to any one of claims 1 to 5,
A sliding material having a friction coefficient of 0.05 or less.

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