WO2022176113A1 - Sliding coating film and sliding member - Google Patents

Sliding coating film and sliding member Download PDF

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Publication number
WO2022176113A1
WO2022176113A1 PCT/JP2021/006154 JP2021006154W WO2022176113A1 WO 2022176113 A1 WO2022176113 A1 WO 2022176113A1 JP 2021006154 W JP2021006154 W JP 2021006154W WO 2022176113 A1 WO2022176113 A1 WO 2022176113A1
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Prior art keywords
carbon layer
sliding
layer
piston ring
coating
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PCT/JP2021/006154
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French (fr)
Japanese (ja)
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智之 佐藤
豊 北詰
誉二 岩下
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Ｔｐｒ株式会社
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Priority to PCT/JP2021/006154 priority Critical patent/WO2022176113A1/en
Publication of WO2022176113A1 publication Critical patent/WO2022176113A1/en

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J9/00—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction
    • F16J9/26—Piston-rings, e.g. non-metallic piston-rings, seats therefor; Ring sealings of similar construction characterised by the use of particular materials

Definitions

  • the present invention relates to a sliding coating formed on the sliding surface of a sliding member used in an internal combustion engine, and a sliding member on which the sliding coating is formed.
  • a DLC film is a film with an amorphous structure (amorphous structure) in which sp 2 bonds of carbon atoms corresponding to a graphite structure and sp 3 bonds of carbon atoms corresponding to a diamond structure are mixed.
  • the sp 2 component ratio (sp 2 /(sp 2 +sp 3 )) is large, the physical properties resemble those of graphite (solid lubricity and low friction coefficient), and the sp 3 component ratio (sp 3 /(sp 2 If +sp 3 )) is large, physical properties similar to diamond (excellent in hardness, abrasion resistance and chemical stability) can be obtained, so by adjusting the component ratio, DLC coatings with various properties can be formed. be able to.
  • Patent Document 1 discloses a DLC-coated piston ring, in which, in the direction away from the substrate, an adhesive layer, a metal-containing amorphous carbon layer, and a metal-free non-crystalline carbon layer are formed in order. It is stated that the provision of a deposited crystalline carbon layer provides a piston ring that is easy to manufacture and meets the requirements for frictional resistance/lifetime.
  • Patent Document 2 discloses a protective film formed on internal combustion engine parts such as cams (camshafts) and shims, in which a first diamond-like layer formed on the surface side of the part and a first It is described having a second diamond-like layer formed on the surface of the diamond-like layer and having an intermediate layer between the internal combustion engine component and the first diamond-like layer.
  • a protective film it is possible to provide a protective film that does not peel off or the like even when an action such as a collision occurs between the cam surface and the shim surface.
  • Patent Document 3 in order to solve the problem of preventing the peeling of the DLC film from the substrate due to the compressive stress during film formation, the density is controlled by the brightness of the TEM image of the cross section of the film.
  • the TEM image of the first amorphous hard carbon layer on the material side is brighter than the TEM image of the second amorphous hard carbon layer formed on the surface of the first amorphous hard carbon layer, It is disclosed to prevent delamination from the substrate due to stress.
  • DLC coatings various developments have been made especially from the viewpoint of wear resistance.
  • the present inventors have studied and found that when a DLC layer is formed on an adhesive layer containing a metal such as chromium as in Patent Document 1, the adhesion between the piston ring base material and the adhesive layer is good.
  • the adhesion between the metal-containing adhesive layer and the DLC layer is low, and a peeling phenomenon different from abrasion may occur due to the progression of wear accompanying sliding.
  • An object of the present invention is to provide a sliding coating capable of suppressing such a peeling phenomenon that is different from wear due to progress of wear associated with sliding.
  • the inventors of the present invention conducted extensive research to suppress separation from the interface between the adhesive layer and the second carbon layer due to abrasive wear that occurs on the piston ring surface when foreign matter such as sludge enters the sliding area.
  • the second carbon layer is not a coating with a high diamond component ratio (large sp 3 component ratio) as in the past, but a coating with a low indentation elastic modulus and a high sp 2 component ratio, which bites the sludge. It was decided to relax the local stress at the time of collapse.
  • the indentation elasticity is increased between the adhesive layer and the second carbon layer by having a larger sp 2 component ratio than the second carbon layer and containing no metal.
  • a low modulus first carbon layer was formed.
  • the difference in sp 2 component ratio and density between the first carbon layer and the second carbon layer is small, the bright field image observation by TEM as disclosed in Patent Document 3 (Fig. 2) cannot It was difficult to distinguish between the carbon layer and the second carbon layer.
  • the present inventors focused on the fact that the coating can be identified by the spectral height of the ⁇ bond peak at the CK loss edge ELNES of the TEM-EELS spectrum, and formed a first carbon layer having a specific peak height. The inventors have found that the above problems can be solved by doing so.
  • one embodiment of the present invention is a sliding coating formed on a sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is adhered onto a metallic base material constituting the sliding member.
  • layer, the first carbon layer, and the second carbon layer, and the structure near the electron energy loss edge is a sliding coating in which a peak exists between 280 eV and 290 eV in loss energy, and the peak height is higher in the first carbon layer than in the second carbon layer.
  • Another aspect of the present invention is a sliding coating formed on a sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is formed on a metal base material constituting the sliding member.
  • the loss energy has peaks between 280 eV and 290 eV in the electron energy loss edge vicinity structure (CK loss edge ELNES) spectrum
  • the adhesive layer and the second carbon The sliding coating has a region where the peak height is higher than that of the second carbon layer at the layer boundary.
  • the first carbon layer preferably contains substantially no metal
  • the second carbon layer preferably has a multilayer structure.
  • still another embodiment of the present invention is a sliding member having the above-described sliding film, and the sliding member can be suitably used for, for example, a piston ring.
  • peeling that may occur when the thickness of the DLC coating becomes a thin film of 2 ⁇ m or less due to the progress of wear accompanying sliding, that is, the sliding portion of the DLC coating is separated from the adhesive layer. A phenomenon such as peeling from the interface portion can be suppressed.
  • FIG. 2 shows a cross-sectional image of a piston ring on which a sliding film according to the present embodiment is formed (photograph substituting for drawing).
  • FIG. 1 is a schematic diagram of a reciprocating friction tester used in Experiment 1.
  • FIG. 10 is a top surface laser microscope image and a cross-sectional microscope image of the second carbon layer, showing the results of Experiment 1 (drawing-substituting photographs).
  • FIG. 4 is a graph showing the cross-sectional height of the second carbon layer showing the results of Experiment 1.
  • FIG. 1 It is a top surface laser microscope image and a cross-sectional microscope image of the second carbon layer, showing the reciprocating friction test results of the piston ring on which the sliding coating of the present embodiment is formed (photographs substituted for drawings).
  • 4 is a graph showing the cross-sectional height of the second carbon layer, showing the reciprocating friction test results of the piston ring on which the sliding film of the present embodiment is formed.
  • 4 is a graph showing a TEM-EELS near-energy loss edge structure (CK loss edge ELNES) spectrum of the sliding coating of Example 1.
  • One embodiment of the present invention is a sliding coating formed on the sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is formed on a metallic base material constituting the sliding member, It is a laminate in which an adhesive layer, a first carbon layer, and a second carbon layer are laminated in this order.
  • FIG. 1 shows a schematic cross-sectional view of a piston ring formed with a sliding film according to the present embodiment.
  • the piston ring 10 is mounted in a piston ring groove (not shown) formed in the piston, and reciprocates while sliding on the inner peripheral surface of a cylinder liner (not shown) by the reciprocating motion of the piston.
  • the piston ring 10 according to this embodiment may be used as any of a top ring, a second ring, and an oil ring.
  • an oil ring When applied to an oil ring, a two-piece oil ring consisting of an oil ring body and a coil expander, and a three-piece oil ring consisting of two segments (also called side rails) and a spacer expander. segment of the ring.
  • the piston ring 10 according to the present embodiment is attached to an aluminum alloy piston, and is preferably used as a piston ring for a cast iron cylinder liner or a cylinder whose inner peripheral surface is thermally sprayed.
  • the material of the piston ring base material 11 is not particularly limited as long as it is a material conventionally used as a piston ring base material.
  • stainless steel, spring steel, etc. are preferably used.
  • martensitic stainless steel, silicon chromium steel, etc. are preferably used.
  • the piston ring 10 comprises an adhesion layer 12 made of either Cr, Si—C or W on a piston ring base material 11, and a first carbon layer 13 and a second carbon layer 14 thereon.
  • an adhesion layer 12 made of either Cr, Si—C or W on a piston ring base material 11, and a first carbon layer 13 and a second carbon layer 14 thereon.
  • the adhesion between the piston ring base material and the adhesive layer is good, but the adhesive layer and the DLC
  • the present inventors believe that such a problem (phenomenon) is caused by the fact that the piston ring base material 11 is provided with the adhesive layer 12 made of Cr, Si—C or W. is thinking. A specific experiment in which such knowledge was obtained will be described below.
  • Experiment 1 was conducted using a reciprocating friction tester whose outline is shown in FIG. First, martensitic stainless steel was used as a piston ring base material having a nominal diameter of 86 mm and a width in the sliding direction of 1.2 mm. A piston ring was prepared by forming a film and processing the outer peripheral sliding surface. A piston ring member having a circumference of 20 mm was cut out from each of three positions forming 90° on both sides and the 180° position of the joint facing portion of the piston ring, and tested. The surface roughness of the piston ring member after final finishing was such that the roughness curve was plateau-shaped and the maximum height was Rz 1.0 ⁇ m.
  • the lower test piece 110 is held by a movable block 120 and is made of flake graphite cast iron made of a pearlite matrix, and has a width of 17 mm and a length of 70 mm assuming a cylinder liner made of flake graphite cast iron having a hardness of HRB 100 and carbide precipitation of 3%.
  • a 14 mm thick plate was prepared and subjected to final surface finishing with #600 emery paper, and the surface roughness was 1.2 ⁇ m at the maximum height Rz.
  • test conditions for the reciprocating friction test are shown below.
  • 150 ⁇ l (microliter) of used engine lubricating oil (viscosity before use 0 W-20) after 400 hours of actual engine operation was applied for 1 hour of the test time.
  • ⁇ Test conditions> ⁇ Stroke: 50mm ⁇ Load: 50N ⁇ Speed: 300 cycles/min ⁇ Temperature of lower test piece: 80°C (use heater 122 for heating lower test piece) ⁇ Test time: 60 minutes
  • ⁇ Analysis 1> A TEM combined with a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS) from a film thickness direction cross-section of a thin piece produced by focused ion beam (FIB) processing for the same piston ring as Experiment 1.
  • -EELS was used to analyze the structure near the electron energy loss edge of the carbon layer.
  • the analysis method is as follows. 1. The slope of the background of the CK loss edge ELNES spectrum is corrected, and the intensity is normalized so that the height on the loss edge side becomes 1. 2. The energy value is corrected with reference to standard samples (diamond, graphite). 3. An area with a loss energy of 280 to 310 eV is measured. (Peak total area) 4.
  • Peak separation is performed in the range of loss energy from 280 to 295 eV.
  • the area of the peak near 285 eV after separation is measured.
  • ( sp2 peak area) 5 Take the ratio of the sp2 peak area to the total peak area ( sp2 peak area ratio). Regarding this area ratio, a relative value based on a standard sample (diamond, graphite) is obtained. Let this be the sp 2 component ratio.
  • the first carbon layer 13 is provided between the adhesive layer 12 and the second carbon layer 14, and the loss energy of the first carbon layer and the second carbon layer is A peak exists between 280 eV and 290 eV, and the peak height is higher in the first carbon layer than in the second carbon layer, thereby solving the problem of peeling from the interface with the adhesive layer. can be done.
  • the boundary between the second carbon layer 14 and the adhesive layer 12 and the second carbon layer 14 is measured by TEM-EELS, in the electron energy loss edge vicinity structure spectrum (CK loss edge ELNES), The loss energy has peaks between 280 eV and 290 eV, and a region where the peak height is higher than the peak height of the second carbon layer 14 exists at the boundary between the adhesive layer 12 and the second carbon layer 14. It is also preferable to
  • the thickness of the adhesive layer is not particularly limited, it is preferably 0.1 ⁇ m or more and preferably 2.0 ⁇ m or less from the viewpoint of improving the adhesion between the substrate 11 and the second carbon layer 14.
  • the outer peripheral surface of the piston ring base material 11 may be smoothed, and when smoothed, the smoothing method is not particularly limited, but the surface roughness can be adjusted by lapping or buffing. preferable.
  • the surface roughness of the piston ring base material 11 is preferably adjusted to 0.5 ⁇ m or less at the maximum height Rz in JISB0601 (2001).
  • the first carbon layer 13 is measured by TEM-EELS, which is a combination of transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS). At this time, the irradiation diameter of the electron beam emitted from the electron gun of the TEM is set to be approximately equal to or smaller than the thickness of the first carbon layer. Analysis 1 was measured using a Cs-TEM with a nominal irradiation diameter of 0.1 nm.
  • the method of forming the first carbon layer 13 is not particularly limited, and can be formed by applying a known method.
  • the first carbon layer 13 preferably contains substantially no metal.
  • substantially means that the metal component in the first carbon layer is 3 at % or less, preferably 1 at % or less, and more preferably below the detection limit. Also, the film thickness of the first carbon layer 13 is preferably 0.001 ⁇ m or more and 1 ⁇ m or less.
  • the second carbon layer 14 has an sp 2 component ratio of usually 0.5 or more and 0.7 or less measured by TEM-EELS, which is a combination of transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS). is preferably 0.55 or more and 0.68 or less, and even more preferably 0.58 or more and 0.65 or less.
  • TEM-EELS transmission electron microscope
  • EELS electron energy loss spectroscopy
  • the second carbon layer 14 preferably has a Martens hardness of 6 GPa or more and 13 GPa or less, may be 11 GPa or less, or may be 9 GPa or less.
  • the second carbon layer 14 preferably has an indentation modulus of 250 GPa or less, more preferably 200 GPa or less, and even more preferably 180 GPa or less, as measured by a nanoindentation method.
  • the lower limit is not particularly limited, if the indentation modulus is 120 GPa or more, peeling inside the film is less likely to occur.
  • the hydrogen content of the second carbon layer 14 is preferably 5 at% or less, more preferably 3 at% or less, and more preferably substantially free of hydrogen from the viewpoint of wear resistance.
  • the film thickness of the second carbon layer 14 is preferably 1 ⁇ m or more and 10 ⁇ m or less, and may be 2 ⁇ m or more and may be 3 ⁇ m or more. Also, the film thickness may be 7 ⁇ m or less, or may be 5 ⁇ m or less. Moreover, the second carbon layer 14 preferably has a multilayer structure.
  • the method for producing the first carbon layer and the second carbon layer according to this embodiment is not particularly limited. As an example, there is a method of forming a coating using a filtered cathodic vacuum arc (FCVA) method or a magnetron sputtering method.
  • FCVA filtered cathodic vacuum arc
  • the first carbon layer and the second carbon layer may be formed by film formation a plurality of times while changing the applied bias voltage or without changing the bias voltage.
  • the first carbon layer is preferably a magnetron sputtering method
  • the second carbon layer is a laminate by the FCVA method or the magnetron sputtering method
  • the absolute value of the applied bias voltage is preferably increased.
  • Example 1 A piston ring base material made of stainless steel was set in the FCVA apparatus, and after the inside of the apparatus was evacuated to reduce the pressure, the base material was heated. Thereafter, while a pulse bias voltage in the range of -500 to -1500 V was applied to the substrate, argon gas was introduced into the apparatus and ion bombardment was performed with argon ions. Next, using a sputtering unit installed in the FCVA apparatus, a bias voltage in the range of -50 V to -600 V was applied to the piston ring base material in an argon gas atmosphere, and the adhesive layer had a thickness of 1.0 ⁇ m. was deposited on the piston ring substrate.
  • a sputtering unit was then used to deposit a first carbon layer on the Cr layer.
  • a carbon target was used to deposit a first carbon layer having a thickness of 0.01 ⁇ m in an argon gas atmosphere while a bias voltage within the range of ⁇ 50 V to ⁇ 600 V was applied to the piston ring base material.
  • a carbon target is used with a pulse bias voltage applied to the piston ring base material within the range of -500 V to -3000 V, and an arc current of 50 to 200 A is used to discharge the thickness.
  • a piston ring according to Example 1 was obtained by forming a second carbon layer of 2 ⁇ m.
  • FIG. 6 shows the EELS spectrum obtained by the above measurement.
  • Example 2 A piston ring according to Example 2 was obtained in the same manner as in Example 1, except that the first carbon layer contained a metal (10 at %).
  • the structure near the electron energy loss edge (CK loss edge ELNES spectrum) has a ⁇ -bond peak of the sp2 component between 280 eV and 290 eV, and the peak height is higher than that of the second carbon layer.
  • the carbon layer was higher.
  • Comparative example 1 A piston ring according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the adhesive layer was not provided and the first carbon layer was not provided.
  • Comparative example 2 A piston ring according to Comparative Example 2 was obtained in the same manner as in Example 1, except that the first carbon layer was not provided.
  • Comparative Example 3 A piston ring according to Comparative Example 3 was obtained in the same manner as in Example 1, except that no adhesive layer was provided.
  • the structure near the electron energy loss edge (CK loss edge ELNES spectrum) has a ⁇ -bond peak of the sp2 component between 280 eV and 290 eV, and the peak height is higher than that of the second carbon layer. The carbon layer was higher.
  • Comparative Example 4 A piston ring according to Comparative Example 4 was obtained in the same manner as in Example 1, except that the first carbon layer was formed by the FCVA method and the second carbon layer was formed by the magnetron sputtering method.
  • the structure near the electron energy loss edge (CK loss edge ELNES spectrum) had a ⁇ -bond peak of the sp2 component between the loss energy of 280 eV and 290 eV, but the peak height was higher than that of the first carbon layer.
  • the second carbon layer was higher.
  • Piston ring 11 Piston ring base material 12 Adhesive layer 13 First carbon layer 14 Second carbon layer 100 Upper test piece 110 Lower test piece 120 Movable block 122 Lower test piece heater

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Abstract

The present invention addresses the problem of providing a sliding coating film which is capable of suppressing separation phenomenon that is different from detrition due to sliding. The problem is solved by a sliding coating film which is a multilayer film that is obtained by sequentially superposing an adhesive layer, a first carbon layer and a second carbon layer in this order on a metal-based substrate that constitutes a sliding member, wherein: a peak is present between the loss energy of 280 eV and the loss energy of 290 eV in the electron energy loss near edge structures (C-K loss edge ELNES) of the first carbon layer and the second carbon layer as determined by TEM-EELS; and the peak height of the first carbon layer is higher than the peak height of the second carbon layer.

Description

摺動被膜及び摺動部材Sliding film and sliding member
　本発明は、内燃機関で用いられる摺動部材の摺動面に形成される摺動被膜及びその摺動被膜が形成された摺動部材に関する。 The present invention relates to a sliding coating formed on the sliding surface of a sliding member used in an internal combustion engine, and a sliding member on which the sliding coating is formed.
　内燃機関用ピストンに用いられるピストンリングの外周摺動面は、フリクション低減及び耐摩耗性向上を目的として、ＤＬＣ（ダイヤモンドライクカーボン）被膜により被覆されることがあり、様々な開発が行われている。一般的にＤＬＣ被膜は、グラファイト構造に対応する炭素原子のｓｐ２結合と、ダイヤモンド構造に対応する炭素原子のｓｐ３結合とが混在するアモルファス構造（非晶質構造）の膜である。ここで、ｓｐ２成分比（ｓｐ２／（ｓｐ２＋ｓｐ３））が大きければグラファイトに似た物性（固体潤滑性を有し低摩擦係数）となり、ｓｐ３成分比（ｓｐ３／（ｓｐ２＋ｓｐ３））が大きければダイヤモンドに似た物性（硬さ、耐摩耗性及び化学的安定性に優れる）となるので、その成分比を調整することにより、様々な特性をもつＤＬＣ被膜を形成することができる。 The outer peripheral sliding surface of a piston ring used in a piston for an internal combustion engine is sometimes coated with a DLC (diamond-like carbon) film for the purpose of reducing friction and improving wear resistance, and various developments have been made. . Generally, a DLC film is a film with an amorphous structure (amorphous structure) in which sp 2 bonds of carbon atoms corresponding to a graphite structure and sp 3 bonds of carbon atoms corresponding to a diamond structure are mixed. Here, if the sp 2 component ratio (sp 2 /(sp 2 +sp 3 )) is large, the physical properties resemble those of graphite (solid lubricity and low friction coefficient), and the sp 3 component ratio (sp 3 /(sp 2 If +sp 3 )) is large, physical properties similar to diamond (excellent in hardness, abrasion resistance and chemical stability) can be obtained, so by adjusting the component ratio, DLC coatings with various properties can be formed. be able to.
　摺動部材においてＤＬＣ被膜を有する例として特許文献１には、ＤＬＣコーティングされたピストンリングが開示されており、基板から離れる方向に、順に、接着層、金属含有非晶質炭素層及び無金属非晶質炭素層を堆積して備えることで、製造が容易であり、摩擦抵抗値／製品寿命について要求を満たすピストンリングを提供できることが記載されている。 As an example of having a DLC coating on a sliding member, Patent Document 1 discloses a DLC-coated piston ring, in which, in the direction away from the substrate, an adhesive layer, a metal-containing amorphous carbon layer, and a metal-free non-crystalline carbon layer are formed in order. It is stated that the provision of a deposited crystalline carbon layer provides a piston ring that is easy to manufacture and meets the requirements for frictional resistance/lifetime.
　一方で特許文献２には、カム（カムシャフト）、シム等の内燃機関用部品に形成される保護膜であって、部品の表面側に形成される第一のダイヤモンド様層と、第一のダイヤモンド様層の表面上に形成される第二のダイヤモンド様層を有し、当該内燃機関用部品と第一のダイヤモンド様層との間に中間層を有することが記載されている。このような保護膜により、カム面とシム面との間に衝突等の作用が生じた場合でも、剥離等が生じない保護膜を提供できるとされている。 On the other hand, Patent Document 2 discloses a protective film formed on internal combustion engine parts such as cams (camshafts) and shims, in which a first diamond-like layer formed on the surface side of the part and a first It is described having a second diamond-like layer formed on the surface of the diamond-like layer and having an intermediate layer between the internal combustion engine component and the first diamond-like layer. With such a protective film, it is possible to provide a protective film that does not peel off or the like even when an action such as a collision occurs between the cam surface and the shim surface.
　また、特許文献３には、ＤＬＣ被膜の成膜時の圧縮応力による基板からの剥離を防止するという問題に対し、被膜断面のＴＥＭ像の明るさにより密度を管理すること、具体的には基材側の第１の非晶質硬質炭素層のＴＥＭ像が、第１の非晶質硬質炭素層の表面に形成された第２の非晶質硬質炭素層のＴＥＭ像よりも明るいことで、応力による基板からの剥離を防止することが開示されている。 Further, in Patent Document 3, in order to solve the problem of preventing the peeling of the DLC film from the substrate due to the compressive stress during film formation, the density is controlled by the brightness of the TEM image of the cross section of the film. The TEM image of the first amorphous hard carbon layer on the material side is brighter than the TEM image of the second amorphous hard carbon layer formed on the surface of the first amorphous hard carbon layer, It is disclosed to prevent delamination from the substrate due to stress.
特許第５４３１４５１号Patent No. 5431451 特開２００７－２４６９９６号公報JP 2007-246996 A 特許第４９１８６５６号Patent No. 4918656
　ＤＬＣ被膜に関しては、特に耐摩耗性の観点からさまざまな開発がされている。
　一方で本発明者らが検討したところ、特許文献１のようにクロム等の金属を含有する接着層上にＤＬＣ層を形成した場合、ピストンリング基材と接着層との密着性は良好であるが、金属を含有する接着層とＤＬＣ層との密着性が低く、摺動に伴う摩耗の進行による摩滅とは異なる剥離現象が生じる場合があることを見出した。 Regarding DLC coatings, various developments have been made especially from the viewpoint of wear resistance.
On the other hand, the present inventors have studied and found that when a DLC layer is formed on an adhesive layer containing a metal such as chromium as in Patent Document 1, the adhesion between the piston ring base material and the adhesive layer is good. However, it was found that the adhesion between the metal-containing adhesive layer and the DLC layer is low, and a peeling phenomenon different from abrasion may occur due to the progression of wear accompanying sliding.
　この剥離現象を詳細に説明すると、通常、摺動によってＤＬＣ被膜表面の摩耗が進行する場合、ＤＬＣ表面の摺動箇所は、ＤＬＣ被膜が摩滅し、ＤＬＣ被膜よりも下層に存在する接着層や基材が露出してくるものである。しかしながら本発明者らが検討したところ、部品形状や摺動条件により変動はあるが、ＤＬＣ被膜が徐々に摩耗して、例えば膜厚が２μｍ程度の薄膜となった場合、ＤＬＣ被膜の摺動箇所が接着層との界面部分から剥離する現象が生じる場合があることが判明した。また、スラッジなどの異物が摺動領域に入り込むことで、同様に、ＤＬＣ被膜の摺動箇所が接着層との界面部分から剥離する現象が生じる場合があることが判明した。
　本発明は、このような摺動に伴う摩耗の進行による摩滅とは異なる剥離現象を抑制できる摺動被膜を提供することを課題とする。 To explain this peeling phenomenon in detail, when the wear of the DLC coating surface progresses due to sliding, the DLC coating is worn away at the sliding portion of the DLC surface, and the adhesive layer and substrate existing below the DLC coating are worn away. The material is exposed. However, when the inventors of the present invention have investigated, although there are fluctuations depending on the shape of the part and the sliding conditions, when the DLC coating gradually wears and becomes a thin film with a thickness of, for example, about 2 μm, the sliding part of the DLC coating It was found that a phenomenon of peeling off from the interface with the adhesive layer may occur. In addition, it was found that foreign matter such as sludge enters the sliding region, which may also cause a phenomenon in which the sliding portion of the DLC coating peels off from the interface portion with the adhesive layer.
An object of the present invention is to provide a sliding coating capable of suppressing such a peeling phenomenon that is different from wear due to progress of wear associated with sliding.
　本発明者らは、スラッジなどの異物が摺動領域に入り込むことでピストンリング表面に生じるアブレシブ摩耗により、接着層と第二の炭素層の界面から剥離が生じることを抑制するため研究を重ねた。まず、第二の炭素層を、従来のようにダイヤモンド成分の比率が高い（ｓｐ３成分比が大きい）被膜とするのではなく、押込み弾性率が低くｓｐ２成分比が大きい被膜としてスラッジを噛みこんだ際の局部的な応力を緩和することとした。更に、接着層と第二の炭素層との密着性を上げるため、接着層と第二の炭素層の間に第二の炭素層よりｓｐ２成分比が大きく、且つ金属を含有せず押込み弾性率の低い、第一の炭素層を形成した。しかしながら、第一の炭素層と第二の炭素層のｓｐ２成分比や密度の差が小さいため、特許文献３に開示されたようなＴＥＭによる明視野像観察（図２）では、第一の炭素層と第二の炭素層の識別をすることが困難であった。 The inventors of the present invention conducted extensive research to suppress separation from the interface between the adhesive layer and the second carbon layer due to abrasive wear that occurs on the piston ring surface when foreign matter such as sludge enters the sliding area. . First, the second carbon layer is not a coating with a high diamond component ratio (large sp 3 component ratio) as in the past, but a coating with a low indentation elastic modulus and a high sp 2 component ratio, which bites the sludge. It was decided to relax the local stress at the time of collapse. Furthermore, in order to increase the adhesion between the adhesive layer and the second carbon layer, the indentation elasticity is increased between the adhesive layer and the second carbon layer by having a larger sp 2 component ratio than the second carbon layer and containing no metal. A low modulus first carbon layer was formed. However, since the difference in sp 2 component ratio and density between the first carbon layer and the second carbon layer is small, the bright field image observation by TEM as disclosed in Patent Document 3 (Fig. 2) cannot It was difficult to distinguish between the carbon layer and the second carbon layer.
　そこで本発明者らは、ＴＥＭ－ＥＥＬＳスペクトルのＣ－Ｋ損失端ＥＬＮＥＳにおけるπ結合ピークのスペクトル高さにより、被膜を識別できることに着目し、特定のピーク高さを有する第１の炭素層を形成することで、上記課題を解決できることを見出した。 Therefore, the present inventors focused on the fact that the coating can be identified by the spectral height of the π bond peak at the CK loss edge ELNES of the TEM-EELS spectrum, and formed a first carbon layer having a specific peak height. The inventors have found that the above problems can be solved by doing so.
　すなわち本発明の一形態は、内燃機関で用いられる摺動部材の摺動面に形成される摺動被膜であって、摺動被膜は、摺動部材を構成する金属系基材上に、接着層、第一の炭素層、第二の炭素層、の順に積層された積層被膜であり、第一の炭素層及び第二の炭素層のＴＥＭ－ＥＥＬＳによる電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳ）には、損失エネルギーが２８０ｅＶから２９０ｅＶの間にピークが存在し、そのピーク高さが第二の炭素層より第一の炭素層の方が高い、摺動被膜である。 That is, one embodiment of the present invention is a sliding coating formed on a sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is adhered onto a metallic base material constituting the sliding member. layer, the first carbon layer, and the second carbon layer, and the structure near the electron energy loss edge (CK Loss edge ELNES) is a sliding coating in which a peak exists between 280 eV and 290 eV in loss energy, and the peak height is higher in the first carbon layer than in the second carbon layer.
　また、本発明の別の形態は、内燃機関で用いられる摺動部材の摺動面に形成される摺動被膜であって、前記摺動被膜は、摺動部材を構成する金属系基材上に、接着層、第一の炭素層、第二の炭素層、の順に積層された積層被膜であり、ＴＥＭ－ＥＥＬＳにより、前記第二の炭素層及び前記接着層と前記第二の炭素層の境界部を測定したときに、電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳ）スペクトルにおいて、損失エネルギーが２８０ｅＶから２９０ｅＶの間にそれぞれピークを有し、且つ前記接着層と前記第二の炭素層の境界部に当該ピーク高さが前記第二の炭素層より高い領域が存在する、摺動被膜である。 Another aspect of the present invention is a sliding coating formed on a sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is formed on a metal base material constituting the sliding member. A laminated film in which an adhesion layer, a first carbon layer, and a second carbon layer are laminated in this order, and the second carbon layer and the adhesion layer and the second carbon layer are separated by TEM-EELS. When the boundary portion is measured, the loss energy has peaks between 280 eV and 290 eV in the electron energy loss edge vicinity structure (CK loss edge ELNES) spectrum, and the adhesive layer and the second carbon The sliding coating has a region where the peak height is higher than that of the second carbon layer at the layer boundary.
　前記第一の炭素層は、実質的に金属を含有しないことが好ましく、前記第二の炭素層は多層構造であることが好ましい。
　また、本発明の更に別の実施形態は、上記記載の摺動被膜を有する摺動部材であり、摺動部材としては例えばピストンリングに好適に使用することができる。 The first carbon layer preferably contains substantially no metal, and the second carbon layer preferably has a multilayer structure.
Further, still another embodiment of the present invention is a sliding member having the above-described sliding film, and the sliding member can be suitably used for, for example, a piston ring.
　本発明により、摺動に伴う摩耗の進行によりＤＬＣ被膜の膜厚が２μｍ以下の薄膜となった場合に生じることがある摩滅とは異なる剥離、すなわち、ＤＬＣ被膜の摺動箇所が接着層との界面部分から剥離するような現象を抑制することができる。 According to the present invention, peeling that may occur when the thickness of the DLC coating becomes a thin film of 2 μm or less due to the progress of wear accompanying sliding, that is, the sliding portion of the DLC coating is separated from the adhesive layer. A phenomenon such as peeling from the interface portion can be suppressed.
本実施形態の摺動被膜が形成されたピストンリングの断面模式図を示す。The cross-sectional schematic diagram of the piston ring in which the sliding film of this embodiment was formed is shown. 本実施形態の摺動被膜が形成されたピストンリングの断面画像を示す（図面代用写真）。FIG. 2 shows a cross-sectional image of a piston ring on which a sliding film according to the present embodiment is formed (photograph substituting for drawing). FIG. 実験１で使用した往復動摩擦試験機の概略図である。1 is a schematic diagram of a reciprocating friction tester used in Experiment 1. FIG. 実験１の結果を示す、第二の炭素層の上面レーザー顕微鏡画像と断面顕微鏡像である（図面代用写真）。FIG. 10 is a top surface laser microscope image and a cross-sectional microscope image of the second carbon layer, showing the results of Experiment 1 (drawing-substituting photographs). FIG. 実験１の結果を示す第二の炭素層の断面の高さを示すグラフである。4 is a graph showing the cross-sectional height of the second carbon layer showing the results of Experiment 1. FIG. 本実施形態の摺動被膜が形成されたピストンリングの往復動摩擦試験結果を示す、第二の炭素層の上面レーザー顕微鏡画像と断面顕微鏡像である（図面代用写真）。It is a top surface laser microscope image and a cross-sectional microscope image of the second carbon layer, showing the reciprocating friction test results of the piston ring on which the sliding coating of the present embodiment is formed (photographs substituted for drawings). 本実施形態の摺動被膜が形成されたピストンリングの往復動摩擦試験結果を示す、第二の炭素層の断面の高さを示すグラフである。4 is a graph showing the cross-sectional height of the second carbon layer, showing the reciprocating friction test results of the piston ring on which the sliding film of the present embodiment is formed. 実施例１の摺動被膜のＴＥＭ－ＥＥＬＳによるエネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳ）スペクトルを示すグラフである。4 is a graph showing a TEM-EELS near-energy loss edge structure (CK loss edge ELNES) spectrum of the sliding coating of Example 1. FIG.
　以下、具体的な実施形態を示し説明するが、各実施形態は本発明の一例として示されるものであり、必ずしも請求項に係る発明を特定するものではなく、また、実施形態の中で説明する特徴の全てが、本発明の課題を解決する手段に必須であるとは限らない。 Hereinafter, specific embodiments will be shown and described, but each embodiment is shown as an example of the present invention, and does not necessarily specify the invention according to the claims, and will be described in the embodiments. Not all features are essential to the solution to the problems of the invention.
　本発明の一実施形態は、内燃機関で用いられる摺動部材の摺動面に形成される摺動被膜であって、前記摺動被膜は、摺動部材を構成する金属系基材上に、接着層、第一の炭素層、第二の炭素層の順に積層された積層体である。 One embodiment of the present invention is a sliding coating formed on the sliding surface of a sliding member used in an internal combustion engine, wherein the sliding coating is formed on a metallic base material constituting the sliding member, It is a laminate in which an adhesive layer, a first carbon layer, and a second carbon layer are laminated in this order.
　図１に、本実施形態の摺動被膜が形成されたピストンリングの断面模式図を示す。
　ピストンリング１０は、ピストンに形成されたピストンリング溝（不図示）に装着され、ピストンの往復運動によってシリンダライナ（不図示）の内周面と摺動しながら往復運動する。
　本実施形態に係るピストンリング１０は、トップリング、セカンドリング、オイルリングの何れのピストンリングとして用いてもよい。なお、オイルリングに適用する場合は、オイルリング本体とコイルエキスパンダからなる２ピース構成オイルリングのオイルリング本体、及び２本のセグメント（サイドレールともいう）とスペーサエキスパンダからなる３ピース構成オイルリングのセグメント、のいずれにも適用することができる。
　なお、本実施形態に係るピストンリング１０は、アルミニウム合金製ピストンに装着され、鋳鉄製シリンダライナ又は内周面に溶射が施されたシリンダに対するピストンリングとして好ましく用いられる。 FIG. 1 shows a schematic cross-sectional view of a piston ring formed with a sliding film according to the present embodiment.
The piston ring 10 is mounted in a piston ring groove (not shown) formed in the piston, and reciprocates while sliding on the inner peripheral surface of a cylinder liner (not shown) by the reciprocating motion of the piston.
The piston ring 10 according to this embodiment may be used as any of a top ring, a second ring, and an oil ring. When applied to an oil ring, a two-piece oil ring consisting of an oil ring body and a coil expander, and a three-piece oil ring consisting of two segments (also called side rails) and a spacer expander. segment of the ring.
The piston ring 10 according to the present embodiment is attached to an aluminum alloy piston, and is preferably used as a piston ring for a cast iron cylinder liner or a cylinder whose inner peripheral surface is thermally sprayed.
　ピストンリング基材１１は、従来からピストンリング基材として使用されている材質であれば、材質は特に限定されない。例えば、ステンレス鋼材、ばね鋼材などが好適に用いられ、具体的には、マルテンサイト系ステンレス鋼、シリコンクロム鋼などが好適に用いられる。 The material of the piston ring base material 11 is not particularly limited as long as it is a material conventionally used as a piston ring base material. For example, stainless steel, spring steel, etc. are preferably used. Specifically, martensitic stainless steel, silicon chromium steel, etc. are preferably used.
　ピストンリング１０は、ピストンリング基材１１上に、Ｃｒ、Ｓｉ－Ｃ又はＷのいずれかからなる接着層１２を備え、その上に第一の炭素層１３、及び第二の炭素層１４を備える。
　本実施形態では、特許文献１のようにクロム等の金属を含有する接着層上にＤＬＣ層を形成した場合、ピストンリング基材と接着層との密着性は良好であるが、接着層とＤＬＣ層との密着性が低く、摺動に伴う摩耗の進行による摩滅とは異なる剥離現象が生じることを見出したことに基づくものである。このような課題（現象）は、ピストンリング基材１１上に、Ｃｒ、Ｓｉ－Ｃ又はＷのいずれかからなる接着層１２を備えた形態であることにより生じるものであると、本発明者らは考えている。このような知見を得た具体的な実験について、以下説明する。 The piston ring 10 comprises an adhesion layer 12 made of either Cr, Si—C or W on a piston ring base material 11, and a first carbon layer 13 and a second carbon layer 14 thereon. .
In this embodiment, when the DLC layer is formed on the adhesive layer containing a metal such as chromium as in Patent Document 1, the adhesion between the piston ring base material and the adhesive layer is good, but the adhesive layer and the DLC This is based on the discovery that the adhesiveness to the layer is low, and a peeling phenomenon different from wear due to progress of wear accompanying sliding occurs. The present inventors believe that such a problem (phenomenon) is caused by the fact that the piston ring base material 11 is provided with the adhesive layer 12 made of Cr, Si—C or W. is thinking. A specific experiment in which such knowledge was obtained will be described below.
＜実験１＞
　実験１は、図３に概要を示す往復動摩擦試験機を用いて行った。
　まず、マルテンサイト系ステンレス鋼を呼び径８６ｍｍ、摺動方向の幅が１．２ｍｍのピストンリング基材とし、その外周面に接着層であるＣｒ層と第二の炭素層を２μｍの厚さで成膜し、外周摺動面を加工したピストンリングを準備した。該ピストンリングの合い口対向部１８０°位置と、両側９０°を成す３箇所の各位置から、周長２０ｍｍのピストンリング部材を切り出し、供試した。最終仕上げ後のピストンリング部材の表面粗さは、粗さ曲線がプラトー形状であり、最大高さＲｚ１．０μｍとし、上試験片１００とした。
　下試験片１１０は可動ブロック１２０により保持され、パーライト基地からなる片状黒鉛鋳鉄であり、硬さがＨＲＢ１００、炭化物析出が３％の片状黒鉛鋳鉄製シリンダライナに見立てた幅１７ｍｍ、長さ７０ｍｍ、厚さ１４ｍｍのプレートを作製し、＃６００エメリーペーパーにより最終表面仕上げを行って、表面粗さは最大高さＲｚで１．２μｍであった。 <Experiment 1>
Experiment 1 was conducted using a reciprocating friction tester whose outline is shown in FIG.
First, martensitic stainless steel was used as a piston ring base material having a nominal diameter of 86 mm and a width in the sliding direction of 1.2 mm. A piston ring was prepared by forming a film and processing the outer peripheral sliding surface. A piston ring member having a circumference of 20 mm was cut out from each of three positions forming 90° on both sides and the 180° position of the joint facing portion of the piston ring, and tested. The surface roughness of the piston ring member after final finishing was such that the roughness curve was plateau-shaped and the maximum height was Rz 1.0 μm.
The lower test piece 110 is held by a movable block 120 and is made of flake graphite cast iron made of a pearlite matrix, and has a width of 17 mm and a length of 70 mm assuming a cylinder liner made of flake graphite cast iron having a hardness of HRB 100 and carbide precipitation of 3%. , a 14 mm thick plate was prepared and subjected to final surface finishing with #600 emery paper, and the surface roughness was 1.2 μm at the maximum height Rz.
　往復動摩擦試験の試験条件を以下に示す。上試験片１００と下試験片１１０との摺動面には、エンジン実機運転４００時間後の使用済みエンジン潤滑油（使用前粘度０Ｗ－２０）を試験時間１時間に１５０μｌ（マイクロリットル）給油した。
＜試験条件＞
・ストローク：５０ｍｍ
・荷重：５０Ｎ
・速度：３００ｃｙｃｌｅ／ｍｉｎ
・下試験片の温度：８０℃（下試験片加熱用ヒータ１２２使用）
・試験時間：６０ｍｉｎ The test conditions for the reciprocating friction test are shown below. On the sliding surface between the upper test piece 100 and the lower test piece 110, 150 μl (microliter) of used engine lubricating oil (viscosity before use 0 W-20) after 400 hours of actual engine operation was applied for 1 hour of the test time. .
<Test conditions>
・Stroke: 50mm
・Load: 50N
・Speed: 300 cycles/min
・Temperature of lower test piece: 80°C (use heater 122 for heating lower test piece)
・Test time: 60 minutes
　結果を図４に示す。図４の断面図（ｂ）に示すように、第二の炭素層の中心部が接着層であるＣｒ層との界面部分から剥離していることがわかる。 The results are shown in Figure 4. As shown in the cross-sectional view (b) of FIG. 4, it can be seen that the central portion of the second carbon layer is separated from the interface portion with the Cr layer, which is the adhesive layer.
＜分析１＞
　実験１と同様のピストンリングに対し、集束イオンビーム（ＦＩＢ）加工によって製作した薄片の、被膜厚さ方向断面から、透過型電子顕微鏡（ＴＥＭ）に電子エネルギー損失分光法（ＥＥＬＳ）を組み合わせたＴＥＭ－ＥＥＬＳを用いて、炭素層の電子エネルギー損失端近傍構造の分析を行った。分析方法は以下の通りである。
１．Ｃ－Ｋ損失端ＥＬＮＥＳスペクトルのバックグラウンドの傾きを補正し、損失端側の高さが１になるよう強度を規格化する。
２．標準試料（ダイヤモンド、グラファイト）を参考に、エネルギー値の補正を行う。
３．損失エネルギーが２８０～３１０ｅＶの面積を計測する。（ピーク全面積）
４．損失エネルギーが２８０～２９５ｅＶの範囲でピーク分離を行う。分離後の２８５ｅＶ付近のピークの面積を計測する。（ｓｐ２ピーク面積）
５．ピーク全面積に対するｓｐ２ピーク面積の比を取る（ｓｐ２ピーク面積比）。この面積比について、標準試料（ダイヤモンド、グラファイト）を基準とした相対値を求める。これをｓｐ２成分割合とする。 <Analysis 1>
A TEM combined with a transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS) from a film thickness direction cross-section of a thin piece produced by focused ion beam (FIB) processing for the same piston ring as Experiment 1. -EELS was used to analyze the structure near the electron energy loss edge of the carbon layer. The analysis method is as follows.
1. The slope of the background of the CK loss edge ELNES spectrum is corrected, and the intensity is normalized so that the height on the loss edge side becomes 1.
2. The energy value is corrected with reference to standard samples (diamond, graphite).
3. An area with a loss energy of 280 to 310 eV is measured. (Peak total area)
4. Peak separation is performed in the range of loss energy from 280 to 295 eV. The area of the peak near 285 eV after separation is measured. ( sp2 peak area)
5. Take the ratio of the sp2 peak area to the total peak area ( sp2 peak area ratio). Regarding this area ratio, a relative value based on a standard sample (diamond, graphite) is obtained. Let this be the sp 2 component ratio.
　実験１から、摺動に伴う摩耗の進行による摩滅により第二の炭素層の膜厚が２μｍ以下の薄膜となった場合、第二の炭素層の摺動箇所の一部が接着層との界面部分から剥離する現象が生じる場合があることを確認した。 From Experiment 1, when the film thickness of the second carbon layer became a thin film of 2 μm or less due to wear due to the progress of wear accompanying sliding, part of the sliding location of the second carbon layer was the interface with the adhesive layer. It was confirmed that the phenomenon of peeling from the part may occur.
　上記判明した問題に対し、本実施形態では、接着層１２と第二の炭素層１４の間に第一の炭素層１３を備え、且つ第一の炭素層及び第二の炭素層の損失エネルギーが２８０ｅＶから２９０ｅＶの間にピークが存在し、そのピーク高さが第二の炭素層より第一の炭素層の方が高いことで、上記接着層との界面部分からの剥離の問題を解決することができる。
　また、ＴＥＭ－ＥＥＬＳにより、第二の炭素層１４及び接着層１２と第二の炭素層１４の境界部を測定したときに、電子エネルギー損失端近傍構造スペクトル（Ｃ－Ｋ損失端ＥＬＮＥＳ）において、損失エネルギーが２８０ｅＶから２９０ｅＶの間にそれぞれピークを有し、且つ接着層１２と第二の炭素層１４の境界部に、当該ピーク高さが第二の炭素層１４のピーク高さより高い領域が存在することも好ましい。 In order to solve the problem identified above, in this embodiment, the first carbon layer 13 is provided between the adhesive layer 12 and the second carbon layer 14, and the loss energy of the first carbon layer and the second carbon layer is A peak exists between 280 eV and 290 eV, and the peak height is higher in the first carbon layer than in the second carbon layer, thereby solving the problem of peeling from the interface with the adhesive layer. can be done.
Further, when the boundary between the second carbon layer 14 and the adhesive layer 12 and the second carbon layer 14 is measured by TEM-EELS, in the electron energy loss edge vicinity structure spectrum (CK loss edge ELNES), The loss energy has peaks between 280 eV and 290 eV, and a region where the peak height is higher than the peak height of the second carbon layer 14 exists at the boundary between the adhesive layer 12 and the second carbon layer 14. It is also preferable to
　接着層の膜厚は特段限定されないが、基材１１と第二の炭素層１４との密着性を向上させる観点から、０．１μｍ以上であることが好ましく、２．０μｍ以下であることが好ましい。
　ピストンリング基材１１の外周面は平滑化されていてもよく、平滑化される場合、平滑化加工の方法は特に限定されないが、ラッピングまたはバフ研磨加工を施し、表面粗さを調整することが好ましい。ピストンリング基材１１の表面粗さは、ＪＩＳＢ０６０１（２００１）における最大高さＲｚで０．５μｍ以下に調整することが好ましい。 Although the thickness of the adhesive layer is not particularly limited, it is preferably 0.1 μm or more and preferably 2.0 μm or less from the viewpoint of improving the adhesion between the substrate 11 and the second carbon layer 14. .
The outer peripheral surface of the piston ring base material 11 may be smoothed, and when smoothed, the smoothing method is not particularly limited, but the surface roughness can be adjusted by lapping or buffing. preferable. The surface roughness of the piston ring base material 11 is preferably adjusted to 0.5 μm or less at the maximum height Rz in JISB0601 (2001).
　第一の炭素層１３は、透過型電子顕微鏡（ＴＥＭ）に電子エネルギー損失分光法（ＥＥＬＳ）を組み合わせたＴＥＭ－ＥＥＬＳで測定される。このとき、ＴＥＭの電子銃から照射される電子線の照射径は、第一の炭素層の厚さと比較して同程度若しくはそれよりも小さい径とする。分析１では、Ｃｓ－ＴＥＭを用いて測定し、その照射径は公称０．１ｎｍとした。　第一の炭素層１３を形成する方法は特に限定されず、公知の方法を適用して形成できる。 The first carbon layer 13 is measured by TEM-EELS, which is a combination of transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS). At this time, the irradiation diameter of the electron beam emitted from the electron gun of the TEM is set to be approximately equal to or smaller than the thickness of the first carbon layer. Analysis 1 was measured using a Cs-TEM with a nominal irradiation diameter of 0.1 nm. The method of forming the first carbon layer 13 is not particularly limited, and can be formed by applying a known method.
　第一の炭素層１３は、実質的に金属を含有しないことが好ましい。ここでいう「実質的に」とは、第一の炭素層中に金属成分が３ａｔ％以下であり、１ａｔ％以下であることが好ましく、検出限界以下であることがより好ましい。
　また、第一の炭素層１３の膜厚は０．００１μｍ以上１μｍ以下であることが好ましい。 The first carbon layer 13 preferably contains substantially no metal. The term “substantially” as used herein means that the metal component in the first carbon layer is 3 at % or less, preferably 1 at % or less, and more preferably below the detection limit.
Also, the film thickness of the first carbon layer 13 is preferably 0.001 μm or more and 1 μm or less.
　第二の炭素層１４は、透過型電子顕微鏡（ＴＥＭ）に電子エネルギー損失分光法（ＥＥＬＳ）を組み合わせたＴＥＭ－ＥＥＬＳで測定されるｓｐ２成分比が通常０．５以上０．７以下であることが好ましく、０．５５以上０．６８以下であることがより好ましく、０．５８以上０．６５以下であることが更に好ましい。 The second carbon layer 14 has an sp 2 component ratio of usually 0.5 or more and 0.7 or less measured by TEM-EELS, which is a combination of transmission electron microscope (TEM) and electron energy loss spectroscopy (EELS). is preferably 0.55 or more and 0.68 or less, and even more preferably 0.58 or more and 0.65 or less.
　第二の炭素層１４は、マルテンス硬さが６ＧＰａ以上１３ＧＰａ以下であることが好ましく、１１ＧＰａ以下であってもよく、９ＧＰａ以下であってもよい。
　また、第二の炭素層１４は、ナノインデンテーション法により測定される押込み弾性率が２５０ＧＰａ以下であることが好ましく、２００ＧＰａ以下であることがより好ましく、１８０ＧＰａ以下であることが更に好ましい。一方、下限は特に限定されないが、押込み弾性率が１２０ＧＰａ以上であることで、膜内部の剥離が生じにくくなる。 The second carbon layer 14 preferably has a Martens hardness of 6 GPa or more and 13 GPa or less, may be 11 GPa or less, or may be 9 GPa or less.
In addition, the second carbon layer 14 preferably has an indentation modulus of 250 GPa or less, more preferably 200 GPa or less, and even more preferably 180 GPa or less, as measured by a nanoindentation method. On the other hand, although the lower limit is not particularly limited, if the indentation modulus is 120 GPa or more, peeling inside the film is less likely to occur.
　第二の炭素層１４は、水素含有量が５ａｔ％以下であることが好ましく、３ａｔ％以下であることがより好ましく、実質水素を含まないことが耐摩耗性の観点からより好ましい。 The hydrogen content of the second carbon layer 14 is preferably 5 at% or less, more preferably 3 at% or less, and more preferably substantially free of hydrogen from the viewpoint of wear resistance.
　第二の炭素層１４の膜厚は１μｍ以上１０μｍ以下であることが好ましく、膜厚が２μｍ以上であってよく、３μｍ以上であってよい。また、膜厚が７μｍ以下であってもよく、５μｍ以下であってよい。また、第二の炭素層１４は、多層構造であることが好ましい。 The film thickness of the second carbon layer 14 is preferably 1 μm or more and 10 μm or less, and may be 2 μm or more and may be 3 μm or more. Also, the film thickness may be 7 μm or less, or may be 5 μm or less. Moreover, the second carbon layer 14 preferably has a multilayer structure.
　本実施形態に係る第一の炭素層及び第二の炭素層の製造方法は、特段限定されない。一例としては、フィルタード　カソーディック　バキューム　アーク（ＦＣＶＡ：Ｆｉｌｔｅｒｅｄ　Ｃａｔｈｏｄｉｃ　Ｖａｃｕｕｍ　ａｒｃ）法やマグネトロンスパッタリング法を用いて被膜を形成する方法があげられる。第一の炭素層及び第二の炭素層は、印加するバイアス電圧を変化させて、またはバイアス電圧を変化させることなく複数回成膜することで形成してもよい。
　上記、ＴＥＭ－ＥＥＬＳを用いた炭素層の電子エネルギー損失端近傍構造を所望のものとするための方法としては、第一の炭素層及び第二の炭素層の製造方法において、第一の炭素層はマグネトロンスパッタリング法、第二の炭素層はＦＣＶＡ法又はマグネトロンスパッタリング法による積層とし、印加するバイアス電圧の絶対値を大きくすることが好ましい。 The method for producing the first carbon layer and the second carbon layer according to this embodiment is not particularly limited. As an example, there is a method of forming a coating using a filtered cathodic vacuum arc (FCVA) method or a magnetron sputtering method. The first carbon layer and the second carbon layer may be formed by film formation a plurality of times while changing the applied bias voltage or without changing the bias voltage.
As a method for obtaining a desired structure near the electron energy loss edge of the carbon layer using TEM-EELS, in the method for producing the first carbon layer and the second carbon layer, the first carbon layer is preferably a magnetron sputtering method, the second carbon layer is a laminate by the FCVA method or the magnetron sputtering method, and the absolute value of the applied bias voltage is preferably increased.
　次に、実施例、比較例を用いて本発明についてさらに詳しく説明を行う。なお、本発明は以下の実施例に限定されるものではない。 Next, the present invention will be described in more detail using examples and comparative examples. In addition, the present invention is not limited to the following examples.
（実施例１）
　ステンレス鋼からなるピストンリング基材をＦＣＶＡ装置内にセットした状態で、装置内を真空排気して減圧した後、基材を加熱した。その後に基材に対してパルスバイアス電圧を－５００～－１５００Ｖの範囲で印加した状態で、装置内にアルゴンガスを導入し、アルゴンイオンによりイオンボンバードを行った。
　次にＦＣＶＡ装置内に設置されたスパッタリングユニットを用い、アルゴンガス雰囲気下でピストンリング基材に対してバイアス電圧を－５０Ｖ～－６００Ｖの範囲に印加した状態で、接着層として厚さ１．０μｍのＣｒ層をピストンリング基材上に成膜した。 (Example 1)
A piston ring base material made of stainless steel was set in the FCVA apparatus, and after the inside of the apparatus was evacuated to reduce the pressure, the base material was heated. Thereafter, while a pulse bias voltage in the range of -500 to -1500 V was applied to the substrate, argon gas was introduced into the apparatus and ion bombardment was performed with argon ions.
Next, using a sputtering unit installed in the FCVA apparatus, a bias voltage in the range of -50 V to -600 V was applied to the piston ring base material in an argon gas atmosphere, and the adhesive layer had a thickness of 1.0 μm. was deposited on the piston ring substrate.
　次にスパッタリングユニットを用い、Ｃｒ層上に第一の炭素層を積層した。ピストンリング基材に対してバイアス電圧を－５０Ｖ～－６００Ｖの範囲内で印加した状態で、カーボンターゲットを用いてアルゴンガス雰囲気下で厚さ０．０１μｍの第一の炭素層を成膜した。
　更に第一の炭素層上に、ピストンリング基材に対してパルスバイアス電圧を－５００Ｖ～－３０００Ｖの範囲内で印加した状態でカーボンターゲットを用いて、アーク電流５０～２００Ａで放電し、厚さ２μｍの第二の炭素層を成膜することで、実施例１に係るピストンリングを得た。
　図６に上記測定で得られたＥＥＬＳスペクトルを示す。電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳスペクトル）の損失エネルギーが２８０ｅＶから２９０ｅＶの間にはｓｐ２成分のπ結合ピーク（炭素のＫ殻（１ｓ軌道）にある電子が励起され、反結合性分子軌道に遷移する際に損失するエネルギーのピークであるπ＊ピーク）があり、そのピーク高さは第二の炭素層よりも第一の炭素層の方が高くなっていることがわかる。 A sputtering unit was then used to deposit a first carbon layer on the Cr layer. A carbon target was used to deposit a first carbon layer having a thickness of 0.01 μm in an argon gas atmosphere while a bias voltage within the range of −50 V to −600 V was applied to the piston ring base material.
Furthermore, on the first carbon layer, a carbon target is used with a pulse bias voltage applied to the piston ring base material within the range of -500 V to -3000 V, and an arc current of 50 to 200 A is used to discharge the thickness. A piston ring according to Example 1 was obtained by forming a second carbon layer of 2 μm.
FIG. 6 shows the EELS spectrum obtained by the above measurement. When the loss energy of the structure near the electron energy loss edge (CK loss edge ELNES spectrum) is between 280 eV and 290 eV, the π bond peak of the sp 2 component (the electron in the K shell (1s orbital) of carbon is excited and reversed). It can be seen that there is a peak of energy lost when transitioning to a bonding molecular orbital (π * peak), and the peak height is higher in the first carbon layer than in the second carbon layer. .
（実施例２）
　第一の炭素層に金属を含有した（１０ａｔ％）こと以外は、実施例１と同様に、実施例２に係るピストンリングを得た。電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳスペクトル）の損失エネルギーが２８０ｅＶから２９０ｅＶの間にｓｐ２成分のπ結合ピークがあり、そのピーク高さは第二の炭素層よりも第一の炭素層の方が高くなっていた。 (Example 2)
A piston ring according to Example 2 was obtained in the same manner as in Example 1, except that the first carbon layer contained a metal (10 at %). The structure near the electron energy loss edge (CK loss edge ELNES spectrum) has a π-bond peak of the sp2 component between 280 eV and 290 eV, and the peak height is higher than that of the second carbon layer. The carbon layer was higher.
（比較例１）
　接着層を設けないこと、第一の炭素層を設けないこと以外は、実施例１と同様にして、比較例１に係るピストンリングを得た。 (Comparative example 1)
A piston ring according to Comparative Example 1 was obtained in the same manner as in Example 1, except that the adhesive layer was not provided and the first carbon layer was not provided.
（比較例２）
　第一の炭素層を設けないこと以外は、実施例１と同様に、比較例２に係るピストンリングを得た。 (Comparative example 2)
A piston ring according to Comparative Example 2 was obtained in the same manner as in Example 1, except that the first carbon layer was not provided.
（比較例３）
　接着層を設けないこと以外は、実施例１と同様に、比較例３に係るピストンリングを得た。電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳスペクトル）の損失エネルギーが２８０ｅＶから２９０ｅＶの間にｓｐ２成分のπ結合ピークがあり、そのピーク高さは第二の炭素層よりも第一の炭素層の方が高くなっていた。 (Comparative Example 3)
A piston ring according to Comparative Example 3 was obtained in the same manner as in Example 1, except that no adhesive layer was provided. The structure near the electron energy loss edge (CK loss edge ELNES spectrum) has a π-bond peak of the sp2 component between 280 eV and 290 eV, and the peak height is higher than that of the second carbon layer. The carbon layer was higher.
（比較例４）
　第一の炭素層をＦＣＶＡ法、第二の炭素層をマグネトロンスパッタリング法で成膜したこと以外は、実施例１と同様にして、比較例４に係るピストンリングを得た。電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳスペクトル）の損失エネルギーが２８０ｅＶから２９０ｅＶの間にｓｐ２成分のπ結合ピークがあったが、そのピーク高さは第一の炭素層よりも第二の炭素層の方が高くなっていた。 (Comparative Example 4)
A piston ring according to Comparative Example 4 was obtained in the same manner as in Example 1, except that the first carbon layer was formed by the FCVA method and the second carbon layer was formed by the magnetron sputtering method. The structure near the electron energy loss edge (CK loss edge ELNES spectrum) had a π-bond peak of the sp2 component between the loss energy of 280 eV and 290 eV, but the peak height was higher than that of the first carbon layer. The second carbon layer was higher.
　得られたピストンリングに対して、図３に示す上記実験１の摺動剥離評価を行った。上記実験１の評価において、第二の炭素層の摺動箇所が接着層との界面部分から剥離した場合は×、剥離しなかったが、若干のクラックが生じた場合は〇、剥離しなかった場合は◎とした。その結果は以下のとおりである。また、実施例１のピストンリングに対し上記実験１の往復動摩擦試験を実施した結果を図５ａ及び図５ｂに示す。 The sliding peeling evaluation of Experiment 1 shown in Fig. 3 was performed on the obtained piston ring. In the evaluation of Experiment 1 above, when the sliding portion of the second carbon layer was peeled from the interface with the adhesive layer, it was not peeled, but when some cracks occurred, it was not peeled. ◎ in the case. The results are as follows. 5a and 5b show the results of the reciprocating friction test of Experiment 1 on the piston ring of Example 1. FIG.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
１０　ピストンリング
１１　ピストンリング基材
１２　接着層
１３　第一の炭素層
１４　第二の炭素層
１００　上試験片
１１０　下試験片
１２０　可動ブロック
１２２　下試験片加熱用ヒータ 10 Piston ring 11 Piston ring base material 12 Adhesive layer 13 First carbon layer 14 Second carbon layer 100 Upper test piece 110 Lower test piece 120 Movable block 122 Lower test piece heater

Claims (5)

  1. 　内燃機関で用いられる摺動部材の摺動面に形成される摺動被膜であって、
    　前記摺動被膜は、摺動部材を構成する金属系基材上に、接着層、第一の炭素層、第二の炭素層、の順に積層された積層被膜であり、
    　前記第一の炭素層及び前記第二の炭素層のＴＥＭ－ＥＥＬＳによる電子エネルギー損失端近傍構造（Ｃ－Ｋ損失端ＥＬＮＥＳ）には、損失エネルギーが２８０ｅＶから２９０ｅＶの間にピークが存在し、そのピーク高さが前記第二の炭素層より前記第一の炭素層の方が高い、摺動被膜。     A sliding coating formed on a sliding surface of a sliding member used in an internal combustion engine,
    The sliding coating is a laminated coating in which an adhesive layer, a first carbon layer, and a second carbon layer are laminated in this order on a metal-based base material that constitutes a sliding member,
    In the electron energy loss edge vicinity structure (CK loss edge ELNES) by TEM-EELS of the first carbon layer and the second carbon layer, there is a peak in the loss energy between 280 eV and 290 eV. A sliding coating, wherein the first carbon layer has a higher peak height than the second carbon layer.
  2. 　前記第一の炭素層は、実質的に金属を含有しない、請求項１に記載の摺動被膜。 The sliding coating according to claim 1, wherein the first carbon layer contains substantially no metal.
  3. 　前記第二の炭素層は、多層構造である、請求項１または２に記載の摺動被膜。 The sliding coating according to claim 1 or 2, wherein the second carbon layer has a multilayer structure.
  4. 　請求項１乃至３のいずれか１項に記載の摺動被膜を有する摺動部材。 A sliding member having the sliding film according to any one of claims 1 to 3.
  5. 　ピストンリングである、請求項４に記載の摺動部材。
     
     
          5. The sliding member according to claim 4, which is a piston ring.
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JP2018154873A (en) * 2017-03-17 2018-10-04 日本アイ・ティ・エフ株式会社 Laminate coating film and method of manufacturing the same, and piston ring
JP2020033622A (en) * 2018-08-31 2020-03-05 株式会社リケン Sliding member

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007246996A (en) * 2006-03-16 2007-09-27 Tdk Corp Protective film, and component for use in internal combustion engine provided with the protective film
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