WO2022131057A1 - Film, and piston ring - Google Patents

Film, and piston ring Download PDF

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Publication number
WO2022131057A1
WO2022131057A1 PCT/JP2021/044752 JP2021044752W WO2022131057A1 WO 2022131057 A1 WO2022131057 A1 WO 2022131057A1 JP 2021044752 W JP2021044752 W JP 2021044752W WO 2022131057 A1 WO2022131057 A1 WO 2022131057A1
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Prior art keywords
film
piston ring
amount
resistance
wear
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PCT/JP2021/044752
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French (fr)
Japanese (ja)
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啓二 本多
恒君 劉
弘樹 斉藤
祐司 島
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株式会社リケン
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Publication of WO2022131057A1 publication Critical patent/WO2022131057A1/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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F5/00—Piston rings, e.g. associated with piston crown
    • 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

  • This disclosure relates to a coating and a piston ring provided with the coating.
  • Piston rings are used in the engines of automobiles and the like.
  • the piston ring is mounted in a groove provided on the outer peripheral surface of the piston.
  • the piston ring is required to contribute to high performance of the engine and reduction of fuel consumption due to, for example, wear resistance and seizure resistance characteristics. Conventionally, various efforts have been made to improve the wear resistance of the piston ring.
  • Patent Document 1 the invention described in Patent Document 1 is intended to provide a piston ring for an internal combustion engine having wear resistance, crack resistance and peel resistance.
  • This piston ring has a hard film formed on the outer peripheral sliding surface.
  • This hard film contains Cr, N and Si as constituent elements, has the same crystal structure as CrN, and is solid-dissolved in the crystal lattice at a Si atomic ratio of 1% or more and 9.5% or less. It is composed of the crystalline phase.
  • Patent Document 1 discloses that a film is formed by an ion plating method.
  • a CrN-based film, a TiN-based film, or a laminated film thereof obtained by the ion plating method improves the wear resistance and peeling resistance of the piston ring.
  • the usage environment of the piston ring will become more severe in the future, there is still room for improvement in wear resistance and peeling resistance of these films.
  • Hard chromium nitride is a material with excellent wear resistance. However, there is room for improvement in that cracks may occur due to sliding resistance under the harsh environment as described above.
  • hard titanium nitride TiN is a material having excellent peel resistance because it has a large Young's modulus value.
  • SiN titanium nitride
  • the present disclosure provides a film having sufficiently high levels of wear resistance, peel resistance and crack resistance, and a piston ring having the same.
  • This piston ring includes a base material and a film provided so as to cover at least a part of the surface of the base material, and the film contains Cr, Ti, Si, and N and has a NaCl-type crystal structure.
  • the Ti content of the film is more than 0 at% and 25 at% or less.
  • the piston ring provided with the above-mentioned film can achieve all of wear resistance, peel resistance and crack resistance to a sufficiently high level.
  • the film contains Ti
  • the film formation is promoted by the reaction with the additive contained in the engine oil. That is, Ti in the film promotes the reaction of Zn-DTP (zinc dialkyldithiophosphate) and Mo-DTC (molybdenum dithiocarbamate) in the engine oil to generate a friction reducing substance (for example, MoS 2 ).
  • This friction-reducing substance repeatedly forms and falls off when the piston and piston ring slide back and forth in the engine. Can be maintained in a reduced state.
  • the frictional resistance during sliding is reduced, the load on the film is reduced, and the peeling resistance and wear resistance are also improved.
  • the amount of Si in the film is, for example, more than 0 at% and 6 at% or less.
  • the crystallite size of the film is, for example, 10 to 30 nm.
  • the Ti amount of the film is more than 0 at% and 25 at% or less. According to the studies by the present inventors, when the Ti amount of the film exceeds 25 at%, the corrosion and wear resistance tends to decrease, and the wear amount of the film tends to increase under a specific sliding environment. It is presumed that this decrease in wear resistance is due to the formation of TiN in the film.
  • the amount of Ti in the film is within a range (25 at% or less) in which Ti can be maintained in a solid solution state in CrN.
  • the film according to the present disclosure contains Cr, Ti, Si, and N, has a NaCl-type crystal structure, and has a Ti content of more than 0 at% and 25 at% or less. This film has sufficiently high levels of wear resistance, peel resistance and crack resistance.
  • a film having sufficiently high levels of wear resistance, peel resistance and crack resistance, and a piston ring having the same are provided.
  • FIG. 1 is a cross-sectional view schematically showing an embodiment of the piston ring of the present disclosure.
  • FIG. 2 is a graph showing the measurement results of the coating film according to Examples and Comparative Examples by an X-ray diffractometer.
  • FIG. 3 is a schematic diagram showing the configuration of a slip fatigue tester.
  • FIG. 4 is a photograph showing sliding marks of the piston according to the embodiment.
  • FIG. 5 is a photograph showing sliding marks of the piston according to the embodiment.
  • FIG. 6 is a photograph showing the sliding marks of the piston according to the comparative example.
  • FIG. 7 is a graph in which the results of Examples and Comparative Examples are plotted with the Ti amount of the film as the horizontal axis and the wear amount (relative value) of the film as the vertical axis.
  • FIG. 8 is a graph in which the results of Examples and Comparative Examples are plotted with the Si amount of the film as the horizontal axis and the wear amount (relative value) of the film as the vertical axis.
  • FIG. 1 is a cross-sectional view schematically showing a piston ring according to the present embodiment.
  • the piston ring 10 shown in FIG. 1 is a pressure ring for an internal combustion engine (for example, an automobile engine).
  • the pressure ring is mounted, for example, in a ring groove formed on the side surface of the piston.
  • the pressure ring is a ring that is exposed to an environment where the heat load of the engine is particularly high.
  • the piston ring 10 is annular, for example, has an outer diameter of 40 to 300 mm.
  • the term "annular” as used herein does not necessarily mean a closed circle, and the piston ring 10 may have a joint portion. Further, the piston ring 10 may have a perfect circular shape or an elliptical shape in a plan view.
  • the piston ring 10 has a substantially rectangular shape in the cross section shown in FIG. 1, and the sliding surface 10F may be rounded so as to bulge outward.
  • the piston ring 10 includes a base material 1 and a film 5 provided on the outer peripheral surface (surface corresponding to the sliding surface 10F) of the base material 1.
  • the base material 1 is made of a heat-resistant alloy. Specific examples of the alloy include spring steel and martensitic stainless steel.
  • the base material 1 may have a nitrided layer formed on the surface thereof.
  • the film 5 constitutes the sliding surface 10F.
  • the film 5 contains Cr, Ti, Si and N and has a NaCl-type crystal structure. Whether or not the crystal structure is NaCl type can be determined based on the X-ray diffraction data.
  • the thickness of the film 5 is, for example, 5 to 70 ⁇ m, preferably 10 to 40 ⁇ m.
  • the thickness of the film 5 is 5 ⁇ m or more, the durability and reliability of the piston ring 10 can be ensured, while when the thickness is 70 ⁇ m or less, the high productivity of the film 5 can be ensured.
  • the amount of Ti in the film 5 is more than 0 at% and 25 at% or less, preferably 0.5 to 20 at%, more preferably 3 to 18 at%, and further preferably more than 7 at% and 16 at% or less.
  • the inclusion of Ti in the film 5 promotes the production of friction-reducing substances from the components (eg, molybdenum and sulfur) contained in the engine oil (lubricating oil), resulting in excellent lows within a sufficiently short time from the start of use. Along with developing frictional properties, it is possible to maintain a low friction state.
  • Ti is also substituted and solid-solved in the Cr site of hard chromium nitride (CrN) together with Si, so that the crystal grains are strengthened, thereby improving the crack resistance.
  • the Ti amount of the film 5 is 25 at% or less, it is possible to suppress the formation of TiN in the film 5, and it is possible to suppress the deterioration of wear resistance due to TiN.
  • the amount of Si in the film 5 is preferably more than 0 at% and 6 at% or less, more preferably 0.5 to 4.5 at%, still more preferably 0.7 to 3 at%, and particularly preferably 0.7. It is ⁇ 2 at%.
  • the film 5 containing Si is composed of finely divided crystal grains and has excellent hardness.
  • an appropriate amount of amorphous phase is likely to be formed in the film 5. It is presumed that this amorphous phase contributes to the suppression of cracks.
  • the amount of Si in the film 5 can be adjusted by the amount of Si in the target used when the film 5 is formed by the physical vapor deposition method (PVD method).
  • the crystallite size of the film 5 is preferably 10 to 30 nm, more preferably 15 to 25 nm. When the crystallite size is 30 nm or less, even if the film 5 is worn, the unit of wear at one time becomes small and the wear resistance is improved.
  • the residual stress of compression of the film 5 is preferably 300 to 800 MPa.
  • the stress difference from the base material 1 alloy or nitrided layer
  • the stress difference from the base material 1 can be reduced, thereby peeling at the interface between the base material 1 and the film 5.
  • cracks in the film 5 that are likely to occur due to the addition of Si can be suppressed.
  • the hardness of the film 5 is preferably 1000HV0.1 to 1800HV0.1, more preferably 1100HV0.1 to 1700HV0.1, and even more preferably 1200HV0.1 to 1500HV0.1. If the hardness of the film 5 is less than 1000 HV0.1, cracks are likely to occur because the compressive residual stress is low, while if it is larger than 1800 HV0.1, the compressive residual stress is high, so cracks propagate at once when the critical load is exceeded. , Easy to peel off.
  • the manufacturing method of this embodiment includes the following steps.
  • the step (a) is a step for cleaning the surface of the base material 1 prior to the formation of the film 5.
  • a cleaning process such as degreasing or shot blasting may be performed.
  • bombard cleaning may be performed in the chamber.
  • the formation of the film 5 in the step (b) can be carried out by a physical vapor deposition method.
  • the formation of the film 5 is carried out after the inside of the chamber is made into a nitrogen atmosphere.
  • Examples of the physical vapor deposition method include an ion plating method and a sputtering method. All of these physical vapor deposition methods are carried out in a vacuum chamber, and the nitrogen pressure in the vacuum chamber is set to, for example, in the range of 2 to 6 Pa. Further, the bias voltage is set to, for example, in the range of -5 to -18V.
  • the composition of the film 5 can be adjusted by changing the composition of the target.
  • the Cr—Ti—Si alloy may be used alone, or the Cr—Ti alloy and the Cr—Si alloy may be used in combination, and these alloys may be used in combination with the Cr ingot and / or the Ti ingot. You may.
  • the Si amount and the Ti amount of the film 5 may be adjusted by supplying a Si-containing gas and / or a Ti-containing gas into the chamber.
  • the hardness of the film 5 can be adjusted, and the crystal orientation and crystallite size can be adjusted by adjusting the amount of Si or Ti of the film 5.
  • These physical properties can also be adjusted by the temperature at which the film 5 is formed (deposition temperature).
  • the film formation temperature may be, for example, in the range of 550 ° C. or lower.
  • the residual stress and hardness of the film 5 may be adjusted by adjusting the nitrogen pressure and the bias voltage in the chamber.
  • a ring having the following composition was prepared as a base material for the piston ring.
  • Fe 80.4% by mass ⁇ C: 0.85% by mass -Cr: 17.0% by mass ⁇ Si: 0.5% by mass -Mn: 0.5% by mass ⁇
  • Other elements Remaining
  • Example 1 to 10 and Comparative Examples 1 and 2 The piston rings according to Examples 1 to 10 and Comparative Examples 1 and 2 were produced as follows. That is, first, the substrate was degreased and washed, and then installed in the chamber. The substrate was then bombard-cleaned in the chamber. Then, a Cr—Ti—Si—N film (thickness: about 20 ⁇ m) was formed on the surface of the substrate by the ion plating method under the following conditions.
  • Tables 1 to 3 show the characteristics of the piston ring coatings according to Examples and Comparative Examples. Each characteristic was measured by the following method.
  • Composition of film The composition of the film was measured using EPMA (device name: JXA-8100, manufactured by JEOL Ltd.), and the measurement conditions were an acceleration voltage of 15 kV, an irradiation current of 5.0 ⁇ 10-8 A, and a beam diameter of 10 ⁇ m. From the X-ray diffraction data, it was determined that Ti and Si in the films of Examples 1 to 10 and Comparative Example 1 were solid-solved.
  • FIG. 2 is a graph showing the measurement results by the X-ray diffractometer. As shown in FIG.
  • the film of Comparative Example 2 contained TiN.
  • Hardness The hardness of the film was obtained by performing a hardness test with a test load of 0.98 N based on the method specified in ISO6507 using a Vickers hardness tester (device name: HM-220, manufactured by Mitutoyo). .. (Residual stress)
  • the residual stress of the film was measured using an X-ray stress device (device name: PSPC minute part X-ray stress measuring device, manufactured by Rigaku). Since the relationship of the following equation holds, the residual stress was obtained using the slope of a straight line between the diffraction angle 2 ⁇ and sin2 ⁇ ( ⁇ is the angle between the sample surface normal direction and the diffraction surface normal direction).
  • K is a stress constant (obtained from Young's modulus, Poisson's ratio, and reflection angle ⁇ in a strain-free state), and ⁇ 762 MPa was used.
  • the negative notation in Tables 1 to 3 means that it is the residual stress of compression.
  • ⁇ Slip fatigue test> As a wear acceleration test, a slip fatigue test was performed using a testing machine having the configuration shown in FIG. 3 includes a rotating drum 51, a mechanism for bringing a test piece S (piston ring cutting piece) into contact with the surface of the drum 51, and a mechanism for repeatedly applying a load to the test piece S. , A mechanism for supplying lubricating oil to the sliding portion is provided. As a result, the test piece can be worn in a relatively short time.
  • the test conditions were as follows.
  • -Mating material drum: SUJ2 heat-treated material (diameter 80 mm) -Drum surface temperature: 80 ° C ⁇
  • Dynamic speed Forward / reverse reverse trapezoidal pattern operation (constant acceleration, maximum speed holding time: 10 seconds) ⁇
  • Test load 20-80N ⁇
  • Vibration frequency 50Hz (sine wave)
  • -Lubricating oil Additive-free base oil SAE # 30 (Super Oil N100) ⁇ Lubricating oil supply amount: 0.2 ml / min (1 second dripping, 29 seconds stop) ⁇ Number of cycles: 5 cycles (1 cycle: 140 seconds)
  • FIGS. 4 to 6 are photographs showing sliding marks of the slip fatigue test results.
  • FIGS. 7 and 8 are graphs plotting the amount of wear (relative value) of the coating film according to Examples and Comparative Examples. The “wear amount” on the vertical axis in these graphs is a relative value with respect to the wear amount of Comparative Example 3.

Abstract

This film comprises Cr, Ti, Si, and N, wherein the Ti is contained in an amount of 0 at% to 25 at% (exclusive of 0 at%), and the film has a NaCl-type crystal structure. This piston ring comprises: a substrate; and said film provided to cover at least a portion of the surface of the substrate.

Description

皮膜及びピストンリングFilm and piston ring
　本開示は、皮膜及びこれを備えるピストンリングに関する。 This disclosure relates to a coating and a piston ring provided with the coating.
　自動車等のエンジンにピストンリングが用いられている。ピストンリングは、ピストンの外周面に設けられた溝に装着される。ピストンリングは、例えば、耐摩耗性及び耐焼付性の特性によってエンジンの高性能化及び燃料消費量の低減に寄与することが求められる。従来、ピストンリングの耐摩耗性を向上させるための種々の取り組みがなされてきた。 Piston rings are used in the engines of automobiles and the like. The piston ring is mounted in a groove provided on the outer peripheral surface of the piston. The piston ring is required to contribute to high performance of the engine and reduction of fuel consumption due to, for example, wear resistance and seizure resistance characteristics. Conventionally, various efforts have been made to improve the wear resistance of the piston ring.
　例えば、特許文献１に記載の発明は、耐摩耗性、耐クラック性及び耐剥離性を兼ね備えた内燃機関用ピストンリングを提供すべくなされたものである。このピストンリングは、外周摺動面に形成された硬質皮膜を有する。この硬質皮膜は、Ｃｒ、Ｎ及びＳｉを構成元素とし、ＣｒＮと同一の結晶構造を有し、かつ、その結晶格子中にＳｉ原子比率で１％以上、９．５％以下の割合で固溶した結晶相から構成されている。 For example, the invention described in Patent Document 1 is intended to provide a piston ring for an internal combustion engine having wear resistance, crack resistance and peel resistance. This piston ring has a hard film formed on the outer peripheral sliding surface. This hard film contains Cr, N and Si as constituent elements, has the same crystal structure as CrN, and is solid-dissolved in the crystal lattice at a Si atomic ratio of 1% or more and 9.5% or less. It is composed of the crystalline phase.
特開２００８－１４２２８号公報Japanese Unexamined Patent Publication No. 2008-14228
　近年、エンジンの高出力化及び排気ガス規制に対応することを目的として、例えば、燃焼温度の高温化、低粘度潤滑油の採用、バイオエタノール等の燃料の多様化及び高圧燃料噴射の採用が進展している。これに伴ってピストンリングの使用環境は年々過酷かつ境界潤滑環境になってきている。従来からピストンリングに採用されている表面処理では、耐剥離性、耐摩耗性、耐クラック性の問題により、十分な性能を発揮できない状況が散見されるようになっている。 In recent years, for the purpose of increasing engine output and complying with exhaust gas regulations, for example, increasing the combustion temperature, adopting low-viscosity lubricating oil, diversifying fuels such as bioethanol, and adopting high-pressure fuel injection have progressed. is doing. Along with this, the usage environment of piston rings is becoming harsher and boundary lubrication environment year by year. In the surface treatment that has been conventionally used for piston rings, there are some situations where sufficient performance cannot be exhibited due to problems of peel resistance, wear resistance, and crack resistance.
　上記特許文献１はイオンプレーティング法によって皮膜を形成することを開示している。イオンプレーティング法によるＣｒＮ系皮膜、ＴｉＮ系皮膜又はこれらの積層皮膜は、ピストンリングの耐摩耗性及び耐剥離性を向上させる。しかし、今後、ピストンリングの使用環境がより過酷になることを想定すると、これらの皮膜も耐摩耗性及び耐剥離性について未だ改善の余地がある。 The above-mentioned Patent Document 1 discloses that a film is formed by an ion plating method. A CrN-based film, a TiN-based film, or a laminated film thereof obtained by the ion plating method improves the wear resistance and peeling resistance of the piston ring. However, assuming that the usage environment of the piston ring will become more severe in the future, there is still room for improvement in wear resistance and peeling resistance of these films.
　硬質窒化クロム（ＣｒＮ）は、耐摩耗性に優れる材料である。しかし、上記のような過酷な環境下においては摺動抵抗に起因してクラックが生じ得る点において改善の余地がある。一方、硬質窒化チタン（ＴｉＮ）は、ヤング率の値が大きいことから、耐剥離性に優れる材料である。しかし、上記のような過酷な環境下においては熱負荷に対する耐酸化性や、エンジン内で生成される酸に対する耐腐食性の点において改善の余地がある。 Hard chromium nitride (CrN) is a material with excellent wear resistance. However, there is room for improvement in that cracks may occur due to sliding resistance under the harsh environment as described above. On the other hand, hard titanium nitride (TiN) is a material having excellent peel resistance because it has a large Young's modulus value. However, in the harsh environment as described above, there is room for improvement in terms of oxidation resistance against heat load and corrosion resistance against acid generated in the engine.
　本開示は、耐摩耗性、耐剥離性及び耐クラック性の全てが十分に高水準である皮膜及びこれを備えるピストンリングを提供する。 The present disclosure provides a film having sufficiently high levels of wear resistance, peel resistance and crack resistance, and a piston ring having the same.
　本開示の一側面はピストンリングに関する。このピストンリングは、基材と、基材の表面の少なくとも一部を覆うように設けられた皮膜とを備え、上記皮膜がＣｒとＴｉとＳｉとＮとを含みかつＮａＣｌ型の結晶構造を有し、皮膜のＴｉ量が０ａｔ％超であり且つ２５ａｔ％以下である。 One aspect of this disclosure relates to piston rings. This piston ring includes a base material and a film provided so as to cover at least a part of the surface of the base material, and the film contains Cr, Ti, Si, and N and has a NaCl-type crystal structure. However, the Ti content of the film is more than 0 at% and 25 at% or less.
　上記皮膜を備えるピストンリングは、耐摩耗性、耐剥離性及び耐クラック性の全てを十分に高水準に達成することができる。皮膜がＴｉを含有することで、エンジンオイルに含まれる添加剤との反応によって膜生成が促進される。すなわち、皮膜中のＴｉは、エンジンオイル中のＺｎ－ＤＴＰ（ジアルキルジチオリン酸亜鉛）やＭｏ－ＤＴＣ（モリブテン－ジチオカーバメート）の反応を促進し、摩擦低減物質（例えば、ＭｏＳ２）を生成させる。この摩擦低減物質は、エンジン中におけるピストンとピストンリングの往復摺動の際に、生成と脱落を繰り返すが、Ｔｉによって摩擦低減物質の生成が促進されることで、生成が支配的となり、摩擦抵抗が低減された状態を維持できる。摺動時の摩擦抵抗が低減すると、皮膜への負荷が低減され、耐剥離性や耐摩耗性も向上する。 The piston ring provided with the above-mentioned film can achieve all of wear resistance, peel resistance and crack resistance to a sufficiently high level. When the film contains Ti, the film formation is promoted by the reaction with the additive contained in the engine oil. That is, Ti in the film promotes the reaction of Zn-DTP (zinc dialkyldithiophosphate) and Mo-DTC (molybdenum dithiocarbamate) in the engine oil to generate a friction reducing substance (for example, MoS 2 ). This friction-reducing substance repeatedly forms and falls off when the piston and piston ring slide back and forth in the engine. Can be maintained in a reduced state. When the frictional resistance during sliding is reduced, the load on the film is reduced, and the peeling resistance and wear resistance are also improved.
　皮膜がＳｉを含有することで結晶粒が微細化する。また、皮膜がＳｉ及びＴｉの両方を含むことで、硬質窒化クロム（ＣｒＮ）のＣｒサイトにＳｉ及びＴｉが置換固溶する。これらの事象によって、耐クラック性が向上する。すなわち、仮に微細なクラックが生じてもその伝播が抑制される。皮膜のＳｉ量は、例えば、０ａｔ％超であり且つ６ａｔ％以下である。皮膜の結晶子サイズは、例えば、１０～３０ｎｍである。 Crystal grains become finer because the film contains Si. Further, since the film contains both Si and Ti, Si and Ti are substituted and solid-dissolved in the Cr site of hard chromium nitride (CrN). These events improve crack resistance. That is, even if fine cracks are generated, their propagation is suppressed. The amount of Si in the film is, for example, more than 0 at% and 6 at% or less. The crystallite size of the film is, for example, 10 to 30 nm.
　皮膜のＴｉ量は、上記のとおり、０ａｔ％超であり且つ２５ａｔ％以下である。本発明者らの検討によると、皮膜のＴｉ量が２５ａｔ％を超えると、耐腐食摩耗性が低下し、特定の摺動環境下で皮膜の摩耗量が増加する傾向にある。この耐摩耗性の低下は、皮膜中にＴｉＮが生成することに起因すると推察される。皮膜のＴｉ量はＣｒＮにＴｉが固溶している状態を維持できる範囲（２５ａｔ％以下）である。 As described above, the Ti amount of the film is more than 0 at% and 25 at% or less. According to the studies by the present inventors, when the Ti amount of the film exceeds 25 at%, the corrosion and wear resistance tends to decrease, and the wear amount of the film tends to increase under a specific sliding environment. It is presumed that this decrease in wear resistance is due to the formation of TiN in the film. The amount of Ti in the film is within a range (25 at% or less) in which Ti can be maintained in a solid solution state in CrN.
　本開示の一側面は上記皮膜に関する。すなわち、本開示に係る皮膜は、ＣｒとＴｉとＳｉとＮとを含みかつＮａＣｌ型の結晶構造を有し、Ｔｉ量が０ａｔ％超であり且つ２５ａｔ％以下である。この皮膜は、耐摩耗性、耐剥離性及び耐クラック性の全てが十分に高水準である。 One aspect of this disclosure relates to the above film. That is, the film according to the present disclosure contains Cr, Ti, Si, and N, has a NaCl-type crystal structure, and has a Ti content of more than 0 at% and 25 at% or less. This film has sufficiently high levels of wear resistance, peel resistance and crack resistance.
　本開示によれば、耐摩耗性、耐剥離性及び耐クラック性の全てが十分に高水準である皮膜及びこれを備えるピストンリングが提供される。 According to the present disclosure, a film having sufficiently high levels of wear resistance, peel resistance and crack resistance, and a piston ring having the same are provided.
図１は、本開示のピストンリングの一実施形態を模式的に示す断面図である。FIG. 1 is a cross-sectional view schematically showing an embodiment of the piston ring of the present disclosure. 図２は、実施例及び比較例に係る皮膜のＸ線回折装置による測定結果を示すグラフである。FIG. 2 is a graph showing the measurement results of the coating film according to Examples and Comparative Examples by an X-ray diffractometer. 図３は、すべり疲労試験機の構成を示す模式図である。FIG. 3 is a schematic diagram showing the configuration of a slip fatigue tester. 図４は、実施例に係るピストンの摺動痕を示す写真である。FIG. 4 is a photograph showing sliding marks of the piston according to the embodiment. 図５は、実施例に係るピストンの摺動痕を示す写真である。FIG. 5 is a photograph showing sliding marks of the piston according to the embodiment. 図６は、比較例に係るピストンの摺動痕を示す写真である。FIG. 6 is a photograph showing the sliding marks of the piston according to the comparative example. 図７は、皮膜のＴｉ量を横軸とし、皮膜の摩耗量（相対値）を縦軸として、実施例及び比較例の結果をプロットしたグラフである。FIG. 7 is a graph in which the results of Examples and Comparative Examples are plotted with the Ti amount of the film as the horizontal axis and the wear amount (relative value) of the film as the vertical axis. 図８は、皮膜のＳｉ量を横軸とし、皮膜の摩耗量（相対値）を縦軸として、実施例及び比較例の結果をプロットしたグラフである。FIG. 8 is a graph in which the results of Examples and Comparative Examples are plotted with the Si amount of the film as the horizontal axis and the wear amount (relative value) of the film as the vertical axis.
　以下、本開示の実施形態について詳細に説明する。なお、本発明は以下の実施形態に限定されるものではない。 Hereinafter, embodiments of the present disclosure will be described in detail. The present invention is not limited to the following embodiments.
（ピストンリング）
　図１は本実施形態に係るピストンリングを模式的に示す断面図である。図１に示すピストンリング１０は、内燃機関（例えば、自動車エンジン）用圧力リングである。圧力リングは、例えば、ピストンの側面に形成されたリング溝に装着される。圧力リングは、特にエンジンの熱負荷の高い環境に晒されるリングである。 (piston ring)
FIG. 1 is a cross-sectional view schematically showing a piston ring according to the present embodiment. The piston ring 10 shown in FIG. 1 is a pressure ring for an internal combustion engine (for example, an automobile engine). The pressure ring is mounted, for example, in a ring groove formed on the side surface of the piston. The pressure ring is a ring that is exposed to an environment where the heat load of the engine is particularly high.
　ピストンリング１０は環状であり、例えば、外径が４０～３００ｍｍである。ここでいう「環状」とは、必ずしも閉じた円を意味するものではなく、ピストンリング１０は合口部を有していてもよい。また、ピストンリング１０は、平面視で真円状でもよいし、楕円状でもよい。ピストンリング１０は図１に示す断面において略矩形であり、摺動面１０Ｆは外側に膨らんだ丸みを帯びていてもよい。 The piston ring 10 is annular, for example, has an outer diameter of 40 to 300 mm. The term "annular" as used herein does not necessarily mean a closed circle, and the piston ring 10 may have a joint portion. Further, the piston ring 10 may have a perfect circular shape or an elliptical shape in a plan view. The piston ring 10 has a substantially rectangular shape in the cross section shown in FIG. 1, and the sliding surface 10F may be rounded so as to bulge outward.
　ピストンリング１０は、基材１と、基材１の外周面（摺動面１０Ｆに対応する表面）に設けられた皮膜５とを備える。基材１は、耐熱性を有する合金からなる。合金の具体例として、ばね鋼やマルテンサイト系ステンレス鋼などが挙げられる。基材１は、表面に窒化層が形成されたものであってもよい。 The piston ring 10 includes a base material 1 and a film 5 provided on the outer peripheral surface (surface corresponding to the sliding surface 10F) of the base material 1. The base material 1 is made of a heat-resistant alloy. Specific examples of the alloy include spring steel and martensitic stainless steel. The base material 1 may have a nitrided layer formed on the surface thereof.
　皮膜５は摺動面１０Ｆを構成している。皮膜５は、ＣｒとＴｉとＳｉとＮとを含みかつＮａＣｌ型の結晶構造を有する。結晶構造がＮａＣｌ型であるか否かはＸ線回折データに基づいて判断することができる。 The film 5 constitutes the sliding surface 10F. The film 5 contains Cr, Ti, Si and N and has a NaCl-type crystal structure. Whether or not the crystal structure is NaCl type can be determined based on the X-ray diffraction data.
　皮膜５の厚さは、例えば、５～７０μｍであり、好ましくは１０～４０μｍである。皮膜５の厚さが５μｍ以上であることで、ピストンリング１０の耐久性と信頼性を確保でき、他方、７０μｍ以下であることで、皮膜５の高い生産性を確保できる。 The thickness of the film 5 is, for example, 5 to 70 μm, preferably 10 to 40 μm. When the thickness of the film 5 is 5 μm or more, the durability and reliability of the piston ring 10 can be ensured, while when the thickness is 70 μm or less, the high productivity of the film 5 can be ensured.
　皮膜５におけるＴｉ量は、０ａｔ％超２５ａｔ％以下であり、好ましくは０．５～２０ａｔ％であり、より好ましくは３～１８ａｔ％であり、更に好ましくは７ａｔ％超１６ａｔ％以下である。皮膜５がＴｉを含有することで、エンジンオイル（潤滑油）に含まれる成分（例えば、モリブテン及び硫黄）から摩擦低減物質の生成が促進され、使用開始から十分に短い時間のうちに優れた低摩擦性が発現するとともに、低摩擦の状態を維持できる。これに加え、硬質窒化クロム（ＣｒＮ）のＣｒサイトにＳｉとともにＴｉも置換固溶していることで、結晶粒が強化され、これにより耐クラック性が向上する。皮膜５のＴｉ量が２５ａｔ％以下であることで、皮膜５中にＴｉＮが生成することを抑制でき、ＴｉＮに起因する耐摩耗性の低下を抑制できる。 The amount of Ti in the film 5 is more than 0 at% and 25 at% or less, preferably 0.5 to 20 at%, more preferably 3 to 18 at%, and further preferably more than 7 at% and 16 at% or less. The inclusion of Ti in the film 5 promotes the production of friction-reducing substances from the components (eg, molybdenum and sulfur) contained in the engine oil (lubricating oil), resulting in excellent lows within a sufficiently short time from the start of use. Along with developing frictional properties, it is possible to maintain a low friction state. In addition to this, Ti is also substituted and solid-solved in the Cr site of hard chromium nitride (CrN) together with Si, so that the crystal grains are strengthened, thereby improving the crack resistance. When the Ti amount of the film 5 is 25 at% or less, it is possible to suppress the formation of TiN in the film 5, and it is possible to suppress the deterioration of wear resistance due to TiN.
　皮膜５のＳｉ量は、好ましくは０ａｔ％超６ａｔ％以下であり、より好ましくは０．５～４．５ａｔ％であり、更に好ましくは０．７～３ａｔ％であり、特に好ましくは０．７～２ａｔ％である。Ｓｉを含む皮膜５は微細化した結晶粒で構成され、優れた硬さを有する。皮膜５のＳｉ量が６ａｔ％以下であることで、皮膜５内に適度な量のアモルファス相が形成されやすい。このアモルファス相がクラックの抑制に寄与すると推察される。皮膜５のＳｉ量は、皮膜５を物理蒸着法（ＰＶＤ法）で形成する際に使用するターゲットのＳｉ量で調整することができる。 The amount of Si in the film 5 is preferably more than 0 at% and 6 at% or less, more preferably 0.5 to 4.5 at%, still more preferably 0.7 to 3 at%, and particularly preferably 0.7. It is ~ 2 at%. The film 5 containing Si is composed of finely divided crystal grains and has excellent hardness. When the amount of Si in the film 5 is 6 at% or less, an appropriate amount of amorphous phase is likely to be formed in the film 5. It is presumed that this amorphous phase contributes to the suppression of cracks. The amount of Si in the film 5 can be adjusted by the amount of Si in the target used when the film 5 is formed by the physical vapor deposition method (PVD method).
　皮膜５の結晶子サイズは、好ましくは１０～３０ｎｍであり、より好ましくは１５～２５ｎｍである。結晶子サイズが３０ｎｍ以下であることで、皮膜５が摩耗しても一度に摩耗する単位が小さくなり耐摩耗性が向上する。 The crystallite size of the film 5 is preferably 10 to 30 nm, more preferably 15 to 25 nm. When the crystallite size is 30 nm or less, even if the film 5 is worn, the unit of wear at one time becomes small and the wear resistance is improved.
　皮膜５の圧縮の残留応力は、好ましくは３００～８００ＭＰａである。皮膜５の残留応力（圧縮）が上記範囲内であることで、基材１（合金又は窒化層）との応力差を小さくすることができ、これにより、基材１と皮膜５の界面における剥離を抑制できる。これに加え、Ｓｉの添加で生じやすい皮膜５内のクラックを抑制できる。 The residual stress of compression of the film 5 is preferably 300 to 800 MPa. When the residual stress (compression) of the film 5 is within the above range, the stress difference from the base material 1 (alloy or nitrided layer) can be reduced, thereby peeling at the interface between the base material 1 and the film 5. Can be suppressed. In addition to this, cracks in the film 5 that are likely to occur due to the addition of Si can be suppressed.
　皮膜５の硬さは、好ましくは１０００ＨＶ０．１～１８００ＨＶ０．１であり、より好ましくは１１００ＨＶ０．１～１７００ＨＶ０．１であり、更に好ましくは１２００ＨＶ０．１～１５００ＨＶ０．１である。皮膜５の硬さが１０００ＨＶ０．１未満であると、圧縮残留応力が低いためクラックが発生しやすく、他方、１８００ＨＶ０．１より大きいと圧縮残留応力が高いため臨界荷重を超えると一気にクラックが伝播し、剥離に至りやすい。 The hardness of the film 5 is preferably 1000HV0.1 to 1800HV0.1, more preferably 1100HV0.1 to 1700HV0.1, and even more preferably 1200HV0.1 to 1500HV0.1. If the hardness of the film 5 is less than 1000 HV0.1, cracks are likely to occur because the compressive residual stress is low, while if it is larger than 1800 HV0.1, the compressive residual stress is high, so cracks propagate at once when the critical load is exceeded. , Easy to peel off.
（ピストンリングの製造方法）
　次に、ピストンリング１０の製造方法について説明する。本実施形態の製造方法は、以下の工程を含む。
（ａ）基材１の表面を洗浄する工程。
（ｂ）基材１の表面の少なくとも一部に、物理蒸着法によって皮膜５を形成する工程。 (Manufacturing method of piston ring)
Next, a method of manufacturing the piston ring 10 will be described. The manufacturing method of this embodiment includes the following steps.
(A) A step of cleaning the surface of the base material 1.
(B) A step of forming a film 5 on at least a part of the surface of the base material 1 by a physical vapor deposition method.
　（ａ）工程は、皮膜５の形成に先立ち、基材１の表面を清浄な状態にするための工程である。例えば、脱脂やショットブラストによる洗浄処理を実施すればよい。これに加えて、チャンバー内においてボンバードクリーニングを実施してもよい。 The step (a) is a step for cleaning the surface of the base material 1 prior to the formation of the film 5. For example, a cleaning process such as degreasing or shot blasting may be performed. In addition to this, bombard cleaning may be performed in the chamber.
　（ｂ）工程における皮膜５の形成は、物理蒸着法により実施することができる。皮膜５の形成は、チャンバー内を窒素雰囲気にしてから実施される。物理蒸着法としては、イオンプレーティング法、スパッタリング法などが挙げられる。これらの物理蒸着法はいずれも、真空チャンバー内で実施されるものであり、真空チャンバーの窒素圧力を、例えば、２～６Ｐａの範囲に設定する。また、バイアス電圧を、例えば、－５～－１８Ｖの範囲に設定する。 The formation of the film 5 in the step (b) can be carried out by a physical vapor deposition method. The formation of the film 5 is carried out after the inside of the chamber is made into a nitrogen atmosphere. Examples of the physical vapor deposition method include an ion plating method and a sputtering method. All of these physical vapor deposition methods are carried out in a vacuum chamber, and the nitrogen pressure in the vacuum chamber is set to, for example, in the range of 2 to 6 Pa. Further, the bias voltage is set to, for example, in the range of -5 to -18V.
　ターゲットの組成を変更することで、皮膜５の組成を調整できる。ターゲットとして、Ｃｒ－Ｔｉ－Ｓｉ合金を単独で使用してもよいし、Ｃｒ－Ｔｉ合金とＣｒ－Ｓｉ合金を併用してもよく、これらの合金とＣｒインゴット及び／又はＴｉインゴットとを併用してもよい。チャンバー内にＳｉ含有ガス及び／又はＴｉ含有ガスを供給することによって皮膜５のＳｉ量及びＴｉ量を調整してもよい。皮膜５のＳｉ量又はＴｉ量によって、皮膜５の硬さを調整できるとともに、結晶配向性及び結晶子サイズを調整できる。皮膜５を形成する際の温度（成膜温度）によっても、これらの物性を調整できる。成膜温度は、例えば、５５０℃以下の範囲であればよい。チャンバー内の窒素圧力及びバイアス電圧を調整することで、皮膜５の残留応力及び硬さを調整してもよい。 The composition of the film 5 can be adjusted by changing the composition of the target. As the target, the Cr—Ti—Si alloy may be used alone, or the Cr—Ti alloy and the Cr—Si alloy may be used in combination, and these alloys may be used in combination with the Cr ingot and / or the Ti ingot. You may. The Si amount and the Ti amount of the film 5 may be adjusted by supplying a Si-containing gas and / or a Ti-containing gas into the chamber. The hardness of the film 5 can be adjusted, and the crystal orientation and crystallite size can be adjusted by adjusting the amount of Si or Ti of the film 5. These physical properties can also be adjusted by the temperature at which the film 5 is formed (deposition temperature). The film formation temperature may be, for example, in the range of 550 ° C. or lower. The residual stress and hardness of the film 5 may be adjusted by adjusting the nitrogen pressure and the bias voltage in the chamber.
　この製造方法によれば、耐摩耗性、耐剥離性及び耐クラック性の全てが十分に高水準であるピストンリング１０を製造することができる。 According to this manufacturing method, it is possible to manufacture the piston ring 10 having sufficiently high levels of wear resistance, peeling resistance and crack resistance.
　以下、本開示について実施例及び比較例に基づいてより詳細に説明する。本発明は以下の実施例に限定されるものではない。 Hereinafter, the present disclosure will be described in more detail based on Examples and Comparative Examples. The present invention is not limited to the following examples.
　ピストンリングの基材として、以下の組成のリングを準備した。
・Ｆｅ：８０．４質量％
・Ｃ：０．８５質量％
・Ｃｒ：１７．０質量％
・Ｓｉ：０．５質量％
・Ｍｎ：０．５質量％
・その他の元素：残部 A ring having the following composition was prepared as a base material for the piston ring.
Fe: 80.4% by mass
・ C: 0.85% by mass
-Cr: 17.0% by mass
・ Si: 0.5% by mass
-Mn: 0.5% by mass
・ Other elements: Remaining
（実施例１～１０及び比較例１，２）
　実施例１～１０及び比較例１，２に係るピストンリングを以下のようにしてそれぞれ作製した。すなわち、まず、基材を脱脂及び洗浄した後、チャンバー内に設置した。次いで、チャンバー内において基材をボンバードクリーニングした。その後、イオンプレーティング法によって以下の条件でＣｒ－Ｔｉ－Ｓｉ－Ｎ皮膜（厚さ：約２０μｍ）を基材の表面にそれぞれ形成した。
・ターゲット：Ｃｒ－Ｔｉ－Ｓｉ合金
・アーク電流：１５０Ａ
・チャンバー内の窒素圧力：４．０Ｐａ
・バイアス電圧（Ｖ）：－１０Ｖ
・成膜温度：５００℃ (Examples 1 to 10 and Comparative Examples 1 and 2)
The piston rings according to Examples 1 to 10 and Comparative Examples 1 and 2 were produced as follows. That is, first, the substrate was degreased and washed, and then installed in the chamber. The substrate was then bombard-cleaned in the chamber. Then, a Cr—Ti—Si—N film (thickness: about 20 μm) was formed on the surface of the substrate by the ion plating method under the following conditions.
-Target: Cr-Ti-Si alloy-Arc current: 150A
-Nitrogen pressure in the chamber: 4.0 Pa
-Bias voltage (V): -10V
-Film film temperature: 500 ° C
（比較例３）
　ターゲットとしてＣｒインゴットを単独で使用したことの他は、上記実施例と同様にしてＣｒ－Ｎ皮膜（厚さ：約２０μｍ）を基材の表面に形成した。 (Comparative Example 3)
A Cr—N film (thickness: about 20 μm) was formed on the surface of the base material in the same manner as in the above embodiment, except that the Cr ingot was used alone as the target.
＜皮膜特性＞
　表１～３に実施例及び比較例に係るピストンリングの皮膜の特性を示す。なお、各特性は以下の方法で測定した。
（皮膜の組成）
　皮膜の組成は、ＥＰＭＡ（装置名：ＪＸＡ－８１００、日本電子製）を使用し、測定条件は、加速電圧１５ｋＶ、照射電流５．０×１０－８Ａ、ビーム径１０μｍにて測定した。なお、Ｘ線回折データから、実施例１～１０及び比較例１の皮膜におけるＴｉ及びＳｉは固溶していると判断した。図２はＸ線回折装置による測定結果を示すグラフである。図２に示されたように、比較例２の皮膜はＴｉＮを含むものであった。
（硬さ）
　皮膜の硬さは、ビッカース硬さ試験機（装置名：ＨＭ－２２０、ミツトヨ製）を使用し、ＩＳＯ６５０７に規定された方法に基づき、試験荷重０．９８Ｎにて硬さ試験を行って得た。
（残留応力）
　皮膜の残留応力は、Ｘ線応力装置（装置名:ＰＳＰＣ微小部Ｘ線応力測定装置、リガク製）を使用して測定した。下記式の関係が成り立つことから、回折角２θとｓｉｎ２ψ（ψは試料面法線方向と回折面法線方向との角度）の直線の傾きを利用して残留応力を求めた。
　σ(残留応力)＝Ｋ・∂(２θ)／∂(ｓｉｎ２ψ)
　式中、Ｋは応力定数（ヤング率、ポアソン比、無歪状態における反射角θから求められる）で、－７６２ＭＰａを使用した。測定は、Ｃｒ管球、電圧３５ｋＶ、電流４０ｍＡ、コリメータ１ｍｍ、ψとして６点（０、１８、２７、３３、３９、４５ｄｅｇ.）、測定時間９０秒、回折角ＣｒＮ(３１１)、２θ＝１３２．８６°の条件で、並傾法により測定した。なお、表１～３におけるマイナスの表記は圧縮の残留応力であることを意味する。
（結晶子サイズ）
　皮膜の結晶子サイズは、Ｘ線回折装置（装置名：ＳｍａｒｔＬａｂ、リガク製）を使用し、ＣｒＮ(２００)面にて、次のＳｃｈｅｒｒｅｒの式を用いて算出した。
　結晶子サイズ＝Ｋλ／βｃｏｓθ
　式中、ＫはＳｃｈｅｒｒｅｒの定数で０．９４、λはＸ線の波長（Ｃｕ：１．５４０６Å）、βは半値幅、θはＢｒａｇｇ角である。 <Film characteristics>
Tables 1 to 3 show the characteristics of the piston ring coatings according to Examples and Comparative Examples. Each characteristic was measured by the following method.
(Composition of film)
The composition of the film was measured using EPMA (device name: JXA-8100, manufactured by JEOL Ltd.), and the measurement conditions were an acceleration voltage of 15 kV, an irradiation current of 5.0 × 10-8 A, and a beam diameter of 10 μm. From the X-ray diffraction data, it was determined that Ti and Si in the films of Examples 1 to 10 and Comparative Example 1 were solid-solved. FIG. 2 is a graph showing the measurement results by the X-ray diffractometer. As shown in FIG. 2, the film of Comparative Example 2 contained TiN.
(Hardness)
The hardness of the film was obtained by performing a hardness test with a test load of 0.98 N based on the method specified in ISO6507 using a Vickers hardness tester (device name: HM-220, manufactured by Mitutoyo). ..
(Residual stress)
The residual stress of the film was measured using an X-ray stress device (device name: PSPC minute part X-ray stress measuring device, manufactured by Rigaku). Since the relationship of the following equation holds, the residual stress was obtained using the slope of a straight line between the diffraction angle 2θ and sin2ψ (ψ is the angle between the sample surface normal direction and the diffraction surface normal direction).
σ (residual stress) = K ・ ∂ (2θ) / ∂ (sin2ψ)
In the formula, K is a stress constant (obtained from Young's modulus, Poisson's ratio, and reflection angle θ in a strain-free state), and −762 MPa was used. The measurement was performed with a Cr tube, voltage 35 kV, current 40 mA, collimator 1 mm, 6 points (0, 18, 27, 33, 39, 45 deg.), Measurement time 90 seconds, diffraction angle CrN (311), 2θ = 132. It was measured by the parallel tilt method under the condition of .86 °. The negative notation in Tables 1 to 3 means that it is the residual stress of compression.
(Crystal size)
The crystallite size of the film was calculated using the following Scherrer equation on the CrN (200) plane using an X-ray diffractometer (device name: SmartLab, manufactured by Rigaku).
Crystallite size = Kλ / βcosθ
In the formula, K is a Scherrer constant of 0.94, λ is an X-ray wavelength (Cu: 1.5406 Å), β is a half width, and θ is a Bragg angle.
＜すべり疲労試験＞
　摩耗加速試験として、図３に示す構成の試験機を使用してすべり疲労試験を行った。図３に示す試験機５０は、回転するドラム５１と、ドラム５１の表面に対して試験片Ｓ（ピストンリング切断片）を当接させる機構と、試験片Ｓに対して繰り返し荷重を加える機構と、摺動部に潤滑油を供給する機構とを備える。これにより、比較的短時間で試験片を摩耗させることができる。試験条件は次のとおりとした。
・相手材（ドラム）：ＳＵＪ２熱処理材（直径８０ｍｍ）
・ドラム表面温度：８０℃
・動速度：正転逆転台形パターン運転（加速度一定、最高速保持時間：１０秒）
・試験荷重：２０～８０Ｎ
・加振周波数：５０Ｈｚ（正弦波）
・潤滑油：無添加ベースオイルＳＡＥ＃３０（スーパーオイルＮ１００）
・潤滑油の供給量：０．２ｍｌ／分（１秒滴下、２９秒停止）
・サイクル数：５サイクル（１サイクル：１４０秒） <Slip fatigue test>
As a wear acceleration test, a slip fatigue test was performed using a testing machine having the configuration shown in FIG. The testing machine 50 shown in FIG. 3 includes a rotating drum 51, a mechanism for bringing a test piece S (piston ring cutting piece) into contact with the surface of the drum 51, and a mechanism for repeatedly applying a load to the test piece S. , A mechanism for supplying lubricating oil to the sliding portion is provided. As a result, the test piece can be worn in a relatively short time. The test conditions were as follows.
-Mating material (drum): SUJ2 heat-treated material (diameter 80 mm)
-Drum surface temperature: 80 ° C
・ Dynamic speed: Forward / reverse reverse trapezoidal pattern operation (constant acceleration, maximum speed holding time: 10 seconds)
・ Test load: 20-80N
・ Vibration frequency: 50Hz (sine wave)
-Lubricating oil: Additive-free base oil SAE # 30 (Super Oil N100)
・ Lubricating oil supply amount: 0.2 ml / min (1 second dripping, 29 seconds stop)
・ Number of cycles: 5 cycles (1 cycle: 140 seconds)
（摩耗量の測定）
　実施例及び比較例に係るピストンリングを２個ずつ作製し、これらを評価対象としてすべり疲労試験を実施した。すべり疲労試験によって皮膜が摩耗した量を測定した。表１～３に、目視観察による破損評価ランク及び摩耗量（比較例３の摩耗量に対する相対値）を示す。なお、摩耗量は２個（Ｎ＝１，２）のピストンリングの摩耗量の平均値である。図４～６は、すべり疲労試験結果の摺動痕を示す写真である。図７，８は、実施例及び比較例に係る皮膜の摩耗量（相対値）をプロットしたグラフである。これらのグラフにおける縦軸の「摩耗量」は、比較例３の摩耗量に対する相対値である。 (Measurement of wear amount)
Two piston rings according to Examples and Comparative Examples were prepared, and a slip fatigue test was carried out using these as evaluation targets. The amount of wear of the film was measured by the slip fatigue test. Tables 1 to 3 show the damage evaluation rank and the amount of wear (relative values to the amount of wear in Comparative Example 3) by visual observation. The amount of wear is the average value of the amount of wear of the two (N = 1, 2) piston rings. FIGS. 4 to 6 are photographs showing sliding marks of the slip fatigue test results. FIGS. 7 and 8 are graphs plotting the amount of wear (relative value) of the coating film according to Examples and Comparative Examples. The “wear amount” on the vertical axis in these graphs is a relative value with respect to the wear amount of Comparative Example 3.
（皮膜損傷ランク）
　すべり疲労試験後の皮膜表面の摺動痕を目視により観察し、以下の基準に基づいて皮膜損傷ランクを決定した。なお、上記すべり疲労試験は、潤滑油量が少なく、かつ皮膜に高い負荷を掛けた過酷な試験である。皮膜損傷ランクがＡ～Ｄであれば、一般的なエンジン実機において不具合は生じない。
　　Ａ：損傷なし
　　Ｂ：軽微なクラックあり
　　Ｃ：軽微な剥離あり
　　Ｄ：大規模クラック及び軽微な剥離あり
　　Ｅ：大規模クラック及び大規模な剥離あり (Film damage rank)
The sliding marks on the surface of the film after the slip fatigue test were visually observed, and the film damage rank was determined based on the following criteria. The slip fatigue test is a harsh test in which the amount of lubricating oil is small and a high load is applied to the film. If the film damage ranks are A to D, no problem occurs in a general engine actual machine.
A: No damage B: Minor cracks C: Minor peeling D: Large-scale cracks and minor peeling E: Large-scale cracks and large-scale peeling
＜摩擦係数の測定＞
　添加剤（Ｍｏ－ＤＴＣ）を含有するエンジンオイルの存在下、実施例６及び比較例３に係るピストンリングの皮膜の摩擦係数をＯｐｔｉｍｏｌ社製ＳＲＶ試験機にて測定した。試験条件は次のとおりとした。
・相手材（ディスク）：ＳＵＪ２材（直径２４ｍｍ）
・ディスク表面温度：８０℃
・回転速度：０．０１ｍ／秒
・試験荷重：２０Ｎ
・潤滑油：０Ｗ－８相当（ウルトラＮＥＸＴ（商品名）、本田技研工業株式会社製）
・潤滑油の供給量：１００ｍｌ（初期のみ）
・試験時間：６０分
　比較例３に係る皮膜（ＣｒＮ）の摩擦係数を１とすると、実施例６に係る皮膜の摩擦係数の相対値は０．７８であった。 <Measurement of coefficient of friction>
In the presence of engine oil containing an additive (Mo-DTC), the friction coefficient of the piston ring film according to Example 6 and Comparative Example 3 was measured with an SRV tester manufactured by Optimol. The test conditions were as follows.
-Mating material (disc): SUJ2 material (diameter 24 mm)
-Disc surface temperature: 80 ° C
・ Rotation speed: 0.01m / sec ・ Test load: 20N
-Lubricating oil: Equivalent to 0W-8 (Ultra NEXT (trade name), manufactured by Honda Motor Co., Ltd.)
・ Lubricating oil supply: 100 ml (initial only)
-Test time: 60 minutes Assuming that the friction coefficient of the film (CrN) according to Comparative Example 3 was 1, the relative value of the friction coefficient of the film according to Example 6 was 0.78.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
１…基材、５…皮膜、１０…ピストンリング、１０Ｆ…摺動面 1 ... base material, 5 ... film, 10 ... piston ring, 10F ... sliding surface

Claims (6)

  1. 　基材と、
    　前記基材の表面の少なくとも一部を覆うように設けられた皮膜と、
    を備え、
    　前記皮膜がＣｒとＴｉとＳｉとＮとを含みかつＮａＣｌ型の結晶構造を有し、
    　前記皮膜のＴｉ量が０ａｔ％超であり且つ２５ａｔ％以下である、ピストンリング。     With the base material
    A film provided so as to cover at least a part of the surface of the base material, and
    Equipped with
    The film contains Cr, Ti, Si and N and has a NaCl-type crystal structure.
    A piston ring in which the Ti content of the film is more than 0 at% and 25 at% or less.
  2. 　前記皮膜の結晶子サイズが１０～３０ｎｍである、請求項１に記載のピストンリング。 The piston ring according to claim 1, wherein the crystallite size of the film is 10 to 30 nm.
  3. 　前記皮膜の圧縮の残留応力が３００～８００ＭＰａである、請求項１又は２に記載のピストンリング。 The piston ring according to claim 1 or 2, wherein the residual stress of compression of the film is 300 to 800 MPa.
  4. 　前記皮膜の硬さが１０００ＨＶ０．１～１８００ＨＶ０．１である、請求項１～３のいずれか一項に記載のピストンリング。 The piston ring according to any one of claims 1 to 3, wherein the hardness of the film is 1000 HV0.1 to 1800 HV0.1.
  5. 　前記皮膜におけるＳｉ量が０ａｔ％超であり且つ６ａｔ％以下である、請求項１～４のいずれか一項に記載のピストンリング。 The piston ring according to any one of claims 1 to 4, wherein the amount of Si in the film is more than 0 at% and 6 at% or less.
  6. 　ＣｒとＴｉとＳｉとＮとを含み、
    　Ｔｉ量が０ａｔ％超であり且つ２５ａｔ％以下であり、
    　ＮａＣｌ型の結晶構造を有する皮膜。     Including Cr, Ti, Si and N,
    The amount of Ti is more than 0 at% and 25 at% or less.
    A film having a NaCl-type crystal structure.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH111763A (en) * 1997-06-09 1999-01-06 Teikoku Piston Ring Co Ltd Hard coating material, sliding member coated with it, and their production
JP2002266697A (en) * 2001-03-08 2002-09-18 Ion Engineering Research Institute Corp Slide member and manufacturing method thereof
JP2003166046A (en) * 2001-11-30 2003-06-13 Kobe Steel Ltd CrN FILM AND METHOD FOR FORMING CrN FILM
JP2006249527A (en) * 2005-03-11 2006-09-21 Kobe Steel Ltd Hard coating, and its forming method
JP2008014228A (en) * 2006-07-06 2008-01-24 Teikoku Piston Ring Co Ltd Piston ring for internal-combustion engine
JP2011025405A (en) * 2001-06-19 2011-02-10 Kobe Steel Ltd Hard film having excellent wear resistance and method for manufacturing the same
JP2012097303A (en) * 2010-10-29 2012-05-24 Kobe Steel Ltd Hard coating formed member and method for forming hard coating
JP5372760B2 (en) * 2006-10-04 2013-12-18 フェデラル−モグル・ブルシャイト・ゲーエムベーハー Piston rings for internal combustion engines
WO2014088096A1 (en) * 2012-12-07 2014-06-12 株式会社リケン Piston ring
JP2019066024A (en) * 2017-10-05 2019-04-25 株式会社リケン piston ring

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH111763A (en) * 1997-06-09 1999-01-06 Teikoku Piston Ring Co Ltd Hard coating material, sliding member coated with it, and their production
JP2002266697A (en) * 2001-03-08 2002-09-18 Ion Engineering Research Institute Corp Slide member and manufacturing method thereof
JP2011025405A (en) * 2001-06-19 2011-02-10 Kobe Steel Ltd Hard film having excellent wear resistance and method for manufacturing the same
JP2003166046A (en) * 2001-11-30 2003-06-13 Kobe Steel Ltd CrN FILM AND METHOD FOR FORMING CrN FILM
JP2006249527A (en) * 2005-03-11 2006-09-21 Kobe Steel Ltd Hard coating, and its forming method
JP2008014228A (en) * 2006-07-06 2008-01-24 Teikoku Piston Ring Co Ltd Piston ring for internal-combustion engine
JP5372760B2 (en) * 2006-10-04 2013-12-18 フェデラル−モグル・ブルシャイト・ゲーエムベーハー Piston rings for internal combustion engines
JP2012097303A (en) * 2010-10-29 2012-05-24 Kobe Steel Ltd Hard coating formed member and method for forming hard coating
WO2014088096A1 (en) * 2012-12-07 2014-06-12 株式会社リケン Piston ring
JP2019066024A (en) * 2017-10-05 2019-04-25 株式会社リケン piston ring

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