Sliding member and internal combustion engine

Abstract

This sliding member is provided with a sliding film on at least the surface thereof. The sliding film contains copper-based alloy particles each containing titanium, in which a titanium oxide layer is provided on at least a portion of an interface between the particles that form the sliding film. In the copper-based alloy particles, the content of titanium is 3.5% by mass to 11.0% by mass inclusive. The copper-based alloy particles comprise precipitates composed of copper and titanium.　This internal combustion engine is characterized by being provided with a sliding member.

Description

Slide member and internal combustion engine

[0001] The present invention relates to a slide member and an internal combustion engine, and more particularly to a slide member that can achieve excellent high-temperature wear resistance and an internal combustion engine equipped with the same.

[0002] Conventionally, Patent Document 1 discloses a valve seat for an internal combustion engine that uses a sliding member formed by spraying particles of a precipitation hardened copper alloy such as Cu-3Ni-0.7Si onto a substrate. In this precipitation hardened copper alloy, Ni is added for the purpose of precipitation strengthening. ２ In order to produce Si, Si is contained, and its thin oxide film reduces adhesive wear.

[0003] Japanese Patent No. 6519962

[0004] However, when a sliding member such as that described in Patent Document 1 is applied to an exhaust-side valve seat of an internal combustion engine exposed to high-temperature gases of over 1000° C., for example, there is room for improvement in that the high-temperature wear resistance is low.

[0005] The present invention has been made in view of the problems associated with the prior art, and has an object to provide a sliding member that can achieve excellent high-temperature wear resistance, and an internal combustion engine equipped with the same.

[0006] As a result of extensive research into achieving the above object, the inventors have found that the above object can be achieved by having a predetermined sliding film containing copper-based alloy particles containing titanium, and having a titanium oxide layer at a portion of the interface between the particles that form the sliding film, and have thus completed the present invention.

[0007] That is, the sliding member of the present invention has a sliding film on at least the surface thereof. The sliding film contains copper-based alloy particles containing titanium, and has a titanium oxide layer at a part of the interface between the particles that form the sliding film.

[0008] The internal combustion engine of the present invention is characterized by including the above-mentioned sliding member.

[0009] According to the present invention, the sliding film described above contains copper-based alloy particles containing titanium, and has a titanium oxide layer at a portion of the interface between the particles forming the sliding film. This makes it possible to provide a sliding member that can achieve excellent high-temperature wear resistance, and an internal combustion engine equipped with the same.

[0010] Fig. 1 is a cross-sectional view schematically showing a first embodiment of a slide member of the present invention. Fig. 2 is a cross-sectional view schematically showing a second embodiment of a slide member of the present invention. Fig. 3 is a partial cross-sectional view schematically showing a part of an embodiment of an internal combustion engine of the present invention. Fig. 4 is a cross-sectional scanning electron microscope image of a slide film in Example 1.

[0011] The sliding member and internal combustion engine of the present invention will be described in detail below with reference to the drawings. Note that the dimensional proportions of the drawings cited below are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0012] <Sliding Member> [First Embodiment] As shown in Fig. 1 , a sliding member 1 of the first embodiment includes a substrate 10 and a sliding film 20 formed on the surface of the substrate 10. This sliding film 20 contains titanium-containing copper-based alloy particles 21 as particles constituting the sliding film 20, and has a titanium oxide layer 23 at a part of the interface 20a between the particles constituting the sliding film 20. In addition, this sliding film 20 has pores 20b. It goes without saying that a surface 20c of the sliding film 20 serves as a sliding surface.

[0013] In the present invention, the term "copper-based alloy" refers to an alloy containing copper as a main component, with copper being the largest component in terms of mass %. The same applies to iron-based alloys, cobalt-based alloys, molybdenum-based alloys, chromium-based alloys, and nickel-based alloys, which refer to alloys containing each metal as a main component, with copper being the largest component in terms of mass %.

[0014] In the present invention, the "titanium oxide layer" is formed when titanium present in the surface vicinity of the copper-based alloy particles, which is more likely to come into contact with an oxidizing atmosphere such as the atmosphere, is oxidized in the oxidizing atmosphere such as the atmosphere. Therefore, the titanium-containing copper-based alloy particles obtained at the stage of raw material particles already have a titanium oxide layer on their surfaces.

[0015] Next, the advantages of this embodiment will be described. According to this embodiment, the sliding film 20 contains copper-based alloy particles 21 containing titanium, and has a titanium oxide layer 23 at a part of the interface 20a between the particles that form the sliding film 20. Therefore, the sliding film 20 is resistant to softening even at high temperatures, and excellent high-temperature wear resistance can be achieved.

[0016] Until now, when particles are sprayed onto a substrate by cold spraying to form a sliding film on the substrate, it has been considered preferable that the oxide film on the particle surface is thin or absent, and that when sprayed onto the substrate by cold spraying, the particles undergo plastic deformation, destroying the oxide film and metallurgically bonding the particles together.

[0017] In contrast, in the present invention, titanium, a metal that is easily oxidized, is incorporated into copper to actively form an oxide film on the particle surface. When such titanium-containing copper-based alloy particles are used as raw material particles for cold spraying, the relatively soft copper alloy particles undergo plastic deformation when sprayed onto a substrate by cold spraying, destroying part of the oxide film, metallurgically bonding the alloy particles together, while leaving part of the oxide film intact. Such oxide films have been thought to hinder the improvement of wear resistance, but it has been found that they actually exhibit an excellent effect of improving wear resistance at high temperatures.

[0018] The mechanism of improvement in high-temperature wear resistance of sliding members that is currently assumed will be described in detail below.

[0019] For example, when a sliding film is formed from titanium-containing copper-based alloy particles, the titanium oxide layer present at a portion of the interface between the particles forming the sliding film is more easily dispersed uniformly in the sliding film than the hard particles when the sliding film is formed from copper-based alloy particles and hard particles. Therefore, it is believed that such a titanium oxide layer is more likely to effectively exhibit a pinning effect against plastic flow in the sliding film, suppressing adhesion of the titanium-containing copper-based alloy particles and improving the high-temperature wear resistance of the sliding member.

[0020] Furthermore, for example, the titanium oxide layer can be more easily contained in the sliding film than precipitates contained in copper alloy particles when the sliding film is formed from precipitation-hardened copper alloy particles, and therefore, it is thought that such a titanium oxide layer is more likely to effectively exhibit a pinning effect against plastic flow in the sliding film, suppressing adhesion of titanium-containing copper-based alloy particles and improving the high-temperature wear resistance of the sliding member.

[0021] Furthermore, for example, when a sliding member slides, the titanium oxide layer easily relieves stress applied to the titanium-containing copper-based alloy particles at the interface between the particles forming the sliding film, and therefore, it is thought that such a titanium oxide layer easily suppresses adhesion of the titanium-containing copper-based alloy particles, thereby improving the high-temperature wear resistance of the sliding member.

[0022] However, it is sufficient for the sliding member of the present invention to have the above-mentioned configuration (see, for example, paragraph 0015), and it goes without saying that even if the same effect is obtained by a mechanism other than the above-mentioned mechanism, it is also included in the scope of the present invention.

[0023] Furthermore, according to this embodiment, the titanium oxide that forms the titanium oxide layer itself acts as a solid lubricant on the surface side of the sliding film, improving the sliding properties of the sliding member, thereby improving the wear resistance.

[0024] Here, the specifications and material types of each component will be described in more detail.

[0025] (Substrate) The substrate is not particularly limited, and for example, metals that have been conventionally used as sliding members in internal combustion engines can be used, but aluminum alloys are preferably used because of their high thermal conductivity.

[0026] Examples of the aluminum alloy include A5056, A1050, AC2A, AC8A, ADC12, and AC4CH, which are specified by the Japanese Industrial Standards.

[0027] (Sliding Film) The sliding film is preferably formed of, for example, a particle aggregate. Here, in the present invention, the term "particle aggregate" means that the particles are not completely dissolved but the surfaces of the particles are partially softened or dissolved, and the contact portions of adjacent particles are solidified and bonded to each other, thereby integrating the particles.

[0028] Furthermore, the sliding film preferably has a porosity of 4% by area or less, more preferably 1% by area or less, in its cross section. The fewer and denser the pores, the stronger the sliding film becomes, and the higher the high-temperature wear resistance of the sliding member becomes.

[0029] The porosity of the sliding film can be calculated, for example, by binarizing a scanning electron microscope image through image processing and analyzing the image.

[0030] Furthermore, the sliding film preferably has at least one of amorphous and nanocrystalline structures at the interface between particles forming the sliding film, for example. The formation of fine nanocrystalline or amorphous structures near the interface between particles can improve the wear resistance of the sliding member.

[0031] Amorphous or nanocrystalline structures at the interfaces between particles can be confirmed, for example, by electron backscatter diffraction using a scanning electron microscope, projecting a diffraction pattern onto a detector plane and analyzing the crystal orientation from the projected pattern.

[0032] The sliding film is preferably formed by spraying particles forming the sliding film onto a substrate and deforming the substrate, thereby improving the wear resistance of the sliding member.

[0033] (Copper-based alloy particles) The copper-based alloy particles are not particularly limited as long as they contain titanium and can exhibit the effect of improving the high-temperature wear resistance of the sliding member. For example, the titanium content in the copper-based alloy particles is preferably 1.0 mass% or more and 15.0 mass% or less. If the titanium content in the copper-based alloy particles is less than 1.0 mass%, it may be impossible to form a titanium oxide layer that sufficiently improves the high-temperature wear resistance of the sliding member. On the other hand, if the titanium content in the copper-based alloy particles is more than 11.0 mass%, it may be impossible to uniformly disperse titanium in the copper-based alloy particles. Furthermore, if the titanium content in the copper-based alloy particles is more than 15.0 mass%, it may be possible that a titanium oxide layer is formed over the entire interface between particles that constitute the sliding film.

[0034] From the viewpoint of more reliably improving the high-temperature wear resistance of the sliding member, the titanium content in the copper-based alloy particles is preferably 3.5% by mass or more and 11.0% by mass or less.

[0035] Furthermore, if the titanium content in the copper-based alloy particles exceeds 9.0% by mass, the effect of improving high-temperature wear resistance tends to approach saturation. Therefore, from the viewpoint of effectively dispersing and forming a titanium oxide layer at the interface between particles that form the sliding film and more reliably improving the high-temperature wear resistance of the sliding member, the titanium content in the copper-based alloy particles is preferably 3.5% by mass or more and 9.0% by mass or less.

[0036] Furthermore, from the viewpoint of more effectively dispersing and forming a titanium oxide layer at the interface between particles forming the sliding film and further reliably improving the high-temperature wear resistance of the sliding member, the titanium content in the copper-based alloy particles is preferably 3.5% by mass or more and 8.0% by mass or less.

[0037] Furthermore, from the viewpoint of effectively forming a titanium oxide layer acting as a solid lubricant on the surface side of the sliding film and improving the wear resistance of the sliding member at high temperatures, the titanium content in the copper-based alloy particles is preferably 4.0% by mass or more and 10.0% by mass or less.

[0038] In particular, from the viewpoint of more effectively dispersing and forming a titanium oxide layer at the interface between particles forming the sliding film, and further effectively forming a titanium oxide layer that acts as a solid lubricant on the surface side of the sliding film, thereby further reliably improving the high-temperature wear resistance of the sliding member, it is preferable that the titanium content in the copper-based alloy particles be 4.0% by mass or more and 8.0% by mass or less.

[0039] The titanium-containing copper-based alloy particles may contain aluminum, and the aluminum content in the titanium-containing copper-based alloy particles is preferably, for example, 0.5 mass % or less.

[0040] The titanium-containing copper-based alloy particles preferably contain precipitates of copper and titanium. Examples of such precipitates include Cu. ４ When titanium-containing copper-based alloy particles contain such precipitates, the alloy particles themselves are precipitation-strengthened, thereby improving the wear resistance of the sliding member.

[0041] The above-mentioned precipitates can be confirmed by observing the cross section of the titanium-containing copper-based alloy particles with an energy dispersive X-ray analyzer and a transmission electron microscope.

[0042] The average particle size (equivalent circle diameter) of the titanium-containing copper-based alloy particles is preferably 20 μm to 50 μm, more preferably 20 μm to 40 μm. If the average particle size of the titanium-containing copper-based alloy particles is less than 20 μm or more than 50 μm, it may be difficult to form the desired sliding film with a good yield.

[0043] The average particle size (equivalent circle diameter: diameter of a circle having the same area as the projected area of ​​the particle image) of the titanium-containing copper-based alloy particles can be calculated by binarizing a scanning electron microscope image by image processing and analyzing the image.

[0044] (Titanium Oxide Layer) The titanium oxide layer is not particularly limited as long as it can exhibit the effect of improving the high-temperature wear resistance of the sliding member. Furthermore, the titanium oxide layer is not formed separately on the surface of the copper-based alloy particles, but is formed by oxidizing, in an oxidizing atmosphere such as the atmosphere, titanium present near the surface of the titanium-containing copper-based alloy particles, as described above, which is more likely to come into contact with an oxidizing atmosphere such as the atmosphere. Such a titanium oxide layer appears linear in the cross section of the sliding film. The length of the linear titanium oxide layer depends on the size of the titanium-containing copper-based alloy particles, but is preferably, for example, 10 μm to 40 μm, and more preferably 15 μm to 35 μm. The width of the linear titanium oxide layer is, for example, preferably 0.05 μm to 2 μm, and more preferably 0.1 μm to 1 μm. If the length of the titanium oxide layer is less than 10 μm or the width is less than 0.05 μm, the effect of improving high-temperature wear resistance may be weakened. If the length of the titanium oxide layer exceeds 40 μm or the width exceeds 2 μm, it may not be possible to form a desired sliding film with a good yield.

[0045] The titanium oxide layer as described above can be confirmed by observing the cross section of the sliding film with a scanning electron microscope and an energy dispersive X-ray analyzer.

[0046] 2 is a diagram illustrating a second embodiment of the sliding member of the present invention. In the following embodiments, the same components as those in the first embodiment are designated by the same reference numerals, and detailed descriptions of the invention will be omitted.

[0047] [Second Embodiment] As shown in FIG. 2 , a slide member 2 of the second embodiment has the same structure as the slide member 1 of the first embodiment, except that the slide film 20 further contains metal particles 25 containing at least one metal selected from the group consisting of iron, cobalt, molybdenum, chromium, and nickel and / or ceramic particles 25.

[0048] Next, advantages of this embodiment will be described. According to this embodiment, the sliding film 20 further includes metal particles 25 containing at least one metal selected from the group consisting of iron, cobalt, molybdenum, chromium, and nickel and / or ceramic particles 25. Therefore, in addition to the advantages of the first embodiment, it is possible to achieve superior high-temperature wear resistance and ensure thermal conductivity.

[0049] (Metal Particles, Ceramic Particles) The metal particles and ceramic particles are not particularly limited, but are preferably harder than the titanium-containing copper-based alloy particles, for example.

[0050] Examples of the metal particles include simple metal particles and alloy particles containing iron, cobalt, molybdenum, chromium, or nickel. Examples of alloy particles include iron-based alloy particles, cobalt-based alloy particles, molybdenum-based alloy particles, chromium-based alloy particles, and nickel-based alloy particles. Among these, it is preferable to use cobalt-based alloy particles, which have excellent wear resistance, and specifically, it is preferable to use Co-28Mo-8Cr-2.5Si.

[0051] Examples of the ceramic particles include tungsten carbide particles and alumina particles.

[0052] The average particle size (equivalent circle diameter) of the metal particles or ceramic particles is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less. If the average particle size of the metal particles or ceramic particles is less than 5 μm or more than 40 μm, it may be difficult to form the desired sliding film with a good yield.

[0053] The average particle size (equivalent circle diameter: diameter of a circle having the same area as the projected area of ​​the particle image) of the metal particles or ceramic particles can be calculated by binarizing a scanning electron microscope image by image processing and analyzing the image.

[0054] <Method for manufacturing slide member> The slide member described above can be produced by forming a slide film on the surface of a substrate by cold spraying, for example, in which raw material particles containing the titanium-containing copper-based alloy particles and, if necessary, the metal particles and ceramic particles are sprayed onto the surface of the substrate in an unmelted state.

[0055] The titanium-containing copper-based alloy particles in the raw material particles preferably have an oxygen content of 0.1% by mass or more and 2.0% by mass or less, and more preferably 0.25% by mass or more and 0.8% by mass or less, including the titanium oxide layer on the particle surface. Furthermore, if the oxygen content of the titanium-containing copper-based alloy particles in the raw material particles is less than 0.1% by mass, it may be difficult to form the desired sliding film with a good yield. On the other hand, if the oxygen content of the titanium-containing copper-based alloy particles in the raw material particles is more than 2.0% by mass, it is difficult to produce the titanium-containing copper-based alloy particles themselves.

[0056] The content of metal particles or ceramic particles in the raw material particles is preferably 50 mass % or less. By keeping the content within this range, the content of titanium-containing copper-based alloy particles can be ensured, and the thermal conductivity of the sliding member can be ensured.

[0057] Cold spraying is a method of forming a coating of particle aggregates by colliding raw material particles in an unmolten solid state with an inert gas in a supersonic flow against a substrate without melting or gasifying them.

[0058] The raw material particles can be produced by various methods. However, from the viewpoint of facilitating the production of the raw material particles as solid solution particles, it is preferable to produce them by, for example, water atomization or gas atomization, in which water or gas is sprayed onto a molten titanium-containing copper-based alloy to form fine droplets that are solidified and turned into particles, and water atomization is preferred in order to obtain the desired oxygen content in the powder immediately after atomization.

[0059] In cold spraying, when the titanium-containing copper-based alloy particles are solid solution particles, the titanium-containing copper-based alloy particles have not yet undergone precipitation hardening before they collide with the substrate in a solid phase. Therefore, the titanium-containing copper-based alloy particles undergo plastic deformation to absorb the stress of the collision, preventing the titanium-containing copper-based alloy particles from cracking or bouncing off.

[0060] Furthermore, inside the titanium-containing copper-based alloy particles, the solid solution components copper and titanium are collided with each other by the energy of the collision. ４ The titanium-containing copper-based alloy particles are precipitated as compounds such as Ti to form crystallites with an average particle size of, for example, 5 to 50 nm, and the titanium-containing copper-based alloy particles become precipitation-hardened copper-based alloy particles, thereby improving wear resistance.

[0061] Then, due to the collision of the raw material particles, part of the kinetic energy is converted into thermal energy, and the surfaces of the raw material particles are locally melted and solidified, bonding the raw material particles together to form a particle aggregate containing titanium-containing copper-based alloy particles, and further, a particle aggregate containing metal particles and ceramic particles added as needed in a dispersed state.

[0062] At this time, the surfaces of the raw material particles melt locally, causing diffusion and the formation of precipitates such as intermetallic compounds. However, because the temperatures of the substrate and raw material particles are below the melting point of the raw material particles, the locally melted parts are rapidly cooled, so there is no time for the precipitates to grow into crystals.

[0063] Therefore, nanocrystals or amorphous materials are formed near the interface where the substrate and particles are bonded, or near the interface where particles are bonded to each other.

[0064] The speed at which the raw material particles are sprayed is preferably 300 to 1200 m / s, and more preferably 500 to 1200 m / s.

[0065] The pressure of the working gas against which the raw material particles are blown is preferably 2 to 7 MPa, and more preferably 3.5 to 7 MPa. If the working gas pressure is less than 2 MPa, the particle velocity cannot be obtained, and the porosity may become large.

[0066] The temperature of the working gas depends on the type and particle size of the raw material particles, but is preferably 400 to 1000°C, and more preferably 600 to 1000°C. If the temperature of the working gas is below 400°C, the raw material particles are less likely to undergo plastic deformation, resulting in a high porosity and reduced wear resistance. If the temperature of the working gas exceeds 1000°C, the temperature becomes too close to the melting point of the raw material particles, making the throat of the injection nozzle more likely to become clogged.

[0067] Examples of the working gas include nitrogen gas and helium gas, and these may be used alone or in combination.

[0068] The thickness of the sliding film depends on the temperature and sliding environment of the location where the sliding member is used, but is preferably 0.05 mm to 5.0 mm, and more preferably 0.1 mm to 0.5 mm. If the thickness of the sliding film is less than 0.05 mm, the strength of the sliding film itself may be insufficient, and plastic deformation may occur if the strength of the substrate is low. Furthermore, if the thickness of the sliding film exceeds 5.0 mm, the sliding film may be prone to peeling from the substrate due to the relationship between the residual stress generated during the formation of the sliding film and the interfacial adhesion force.

[0069] 3 is a partial cross-sectional view showing a part of an internal combustion engine according to an embodiment of the present invention. More specifically, it is a partial cross-sectional view showing a valve train including an engine valve. In the following embodiments, the same components as those in the first or second embodiment are designated by the same reference numerals, and detailed descriptions of the invention will be omitted.

[0070] <Internal Combustion Engine> As shown in FIG. 3 , when the cam lobe 40 rotates, the valve lifter 41 is pushed down while compressing the valve spring 42. At the same time, the engine valve 43 is pushed down along a valve guide 45 having a stem seal 44, and the engine valve 43 moves away from its seat 46A in a cylinder head 46, connecting the exhaust port 47 to a combustion chamber (not shown) (the engine valve is open). As the cam lobe 40 continues to rotate, the repulsive force of the valve spring 42 pushes up the engine valve 43 together with the valve lifter 41, retainer 48, and cotter 49. The engine valve 43 contacts the seat 46A, blocking communication between the exhaust port 47 and a combustion chamber (not shown) (the engine valve is closed). The engine valve 43 opens and closes in this manner in synchronization with the rotation of the cam lobe 40. The valve stem 43A of the engine valve 43 passes through the valve guide 45, which is press-fitted into the cylinder head 46, and is installed while being lubricated with oil. Furthermore, a valve face 43B of the engine valve 43, which corresponds to the opening and closing valve of the combustion chamber (not shown), is in contact with or out of contact with a seating portion 46A of the engine valve 43 in the cylinder head 46 during operation. Although the exhaust port 47 side is shown in Fig. 3, the sliding member of the present invention can also be applied to the intake port side (not shown).

[0071] The sliding surface 46a of the engine valve seat 46A in the cylinder head, which is the sliding portion between the cylinder head and the engine valve, is provided with a sliding member having the above-described sliding film, such as the sliding member (1, 2) in the first or second embodiment. This improves the high-temperature wear resistance of the internal combustion engine. Furthermore, the internal combustion engine of the present invention makes it possible to eliminate press-fitted valve seats. As a result, it becomes possible to freely design the exhaust port and intake port and to enlarge the diameter of the engine valve, thereby improving the fuel economy, power output, torque, and other aspects of the engine.

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0073] (Comparative Example 1) As raw material particles, nickel-silicon-containing copper-based alloy particles (composition: Cu-3Ni-0.7Si, particle size (D ５０ A sliding film was formed on the surface of an aluminum alloy substrate by cold spraying under the following conditions to obtain the sliding member of this example. When forming a sliding film on the surface of an aluminum alloy substrate for the valve seat single body tapping test, a sliding film with a sliding film thickness of 0.4 to 0.5 mm was formed on the substrate, and then machined to have the shape of the seating portion of an engine valve in an actual cylinder head. In addition, the particle diameter (D ５０ The particle size (median diameter) was determined by measuring the volume distribution by a laser diffraction / scattering method using a particle size distribution measuring device, Microtrac MT3000EXII, manufactured by Microtrac Bell Co., Ltd., and the diameter at a cumulative frequency of 50% was used.

[0074] Cold spray device: PCS-1000 manufactured by Plasma Giken Kogyo Co., Ltd. Working gas: nitrogen Working gas temperature: 600°C Working gas pressure: 4 MPa Spray distance: 20 mm Aluminum alloy substrate: Material type: A1050 specified by the Japanese Industrial Standards, size: 100 x 100 x 5 mm (for Vickers hardness testing) Material type: A5056 specified by the Japanese Industrial Standards, size: In the completed state of machining of the engine valve seating portion in the cylinder head, the aluminum alloy substrate was pre-processed to prepare a pre-processed aluminum substrate assuming a target sliding film thickness of 0.2 mm (for single valve seat hammering wear testing). Substrate rotation speed: 300 rpm Gun traverse speed: approximately 100 mm / s Raw material particle supply amount: approximately 7 g / min

[0075] (Comparative Example 2) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, nickel-cobalt-silicon-containing copper-based alloy particles (composition: Cu-1.5Ni-1.5Co-0.7Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 31.7 μm) was used to obtain a sliding member of this example.

[0076] (Comparative Example 3) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, nickel-cobalt-silicon-containing copper-based alloy particles shown in Table 1 (composition: Cu-2.2Ni-0.8Co-0.7Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 30.6 μm) was used to obtain a sliding member of this example.

[0077] (Comparative Example 4) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, iron-silicon-containing copper-based alloy particles shown in Table 1 (composition: Cu-3Fe-0.7Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 32.2 μm) was used to obtain a sliding member of this example.

[0078] (Example 1) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, titanium-containing copper-based alloy particles (composition: Cu-3.6Ti, particle size (D ５０ The same operations as in Comparative Example 1 were repeated except that a sintered body (sintered body): 33.2 μm) was used to obtain a sliding member of this example. Fig. 4 is a cross-sectional scanning electron microscope image of the sliding film of this example.

[0079] (Example 2) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, titanium-containing copper-based alloy particles (composition: Cu-5.3Ti, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 29.2 μm) was used to obtain a sliding member of this example.

[0080] (Example 3) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, titanium-containing copper-based alloy particles (composition: Cu-8.3Ti, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 31.1 μm) was used to obtain a sliding member of this example.

[0081] (Example 4) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, titanium-containing copper-based alloy particles (composition: Cu-10.4Ti, particle size (D ５０The same procedure as in Comparative Example 1 was repeated except that a sintered body (sintered body): 29.9 μm) was used to obtain a sliding member of this example.

[0082] (Comparative Example 5) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, nickel-silicon-containing copper-based alloy particles shown in Table 1 (composition: Cu-2.5Ni-0.7Si, particle size (D ５０ 33.1 μm) and cobalt-based alloy particles (composition: Co-28Mo-8Cr-2.5Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that the blending ratio (mass ratio) of these components was 50:50, to obtain a sliding member of this example.

[0083] (Comparative Example 6) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, nickel-silicon-containing copper-based alloy particles shown in Table 1 (composition: Cu-3.5Ni-0.7Si, particle size (D ５０ 32.9 μm) and cobalt-based alloy particles (composition: Co-28Mo-8Cr-2.5Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that the blending ratio (mass ratio) of these components was 50:50, to obtain a sliding member of this example.

[0084] (Example 5) Instead of the nickel-silicon-containing copper-based alloy particles used in Comparative Example 1 as raw material particles, titanium-containing copper-based alloy particles (composition: Cu-3.6Ti, particle size (D ５０ 33.2 μm) and cobalt-based alloy particles (composition: Co-28Mo-8Cr-2.5Si, particle size (D ５０ The same procedure as in Comparative Example 1 was repeated except that the blending ratio (mass ratio) of these components was 50:50, to obtain a sliding member of this example.

[0085]

[0086] (Presence or Absence of Titanium Oxide Layer) The cross section of the sliding film of each example was observed with a scanning electron microscope and an energy dispersive X-ray analyzer to confirm the presence or absence of a titanium oxide layer. The results obtained are also shown in Table 1.

[0087] (Presence or Absence of Copper and Titanium Precipitates) The cross section of the copper-based alloy particles of each example was observed with an energy dispersive X-ray analyzer and a transmission electron microscope to determine whether copper and titanium precipitates (Cu ４ The presence or absence of Ti was confirmed. The results are shown in Table 1.

[0088] (Porosity and area ratio of metal particles / alloy particles / ceramic particles) For each example of the sliding film, five fields of view of the cross section were photographed using a scanning electron microscope with an image field range of 350 μm horizontally and 263 μm vertically, and the images were binarized using an image processing device to calculate the porosity. Furthermore, the area ratio of metal particles / alloy particles / ceramic particles was calculated using the same images, and the area ratio of the base material particles was obtained as the remainder. The results obtained are also shown in Table 1.

[0089] (Presence or absence of amorphous or nanocrystalline) For each example of the sliding film, a diffraction pattern was projected onto the detector surface using electron backscatter diffraction with a scanning electron microscope, and the crystal orientation was analyzed from the projected pattern to confirm the presence or absence of amorphous or nanocrystalline at the interface between particles. The presence of amorphous or nanocrystalline was confirmed for each example of the sliding film.

[0090] [Performance Evaluation] The performance of the sliding members of the above examples was evaluated under the following conditions. The results are shown in Table 1.

[0091] (Vickers hardness test) Test piece shape: 5 x 5 x 10 mm Measurement temperatures: 20°C, 200°C, 300°C, 400°C Number of measurement points: 5 points Measurement load: 500 gf The average value of the Vickers hardness measured at the above 5 points was calculated.

[0092] (Valve seat single-piece hammering abrasion test) Equipment: Valve seat single-piece hammering abrasion test equipment (manufactured by Takachiho Seiki Co., Ltd.) Test temperature: 300°C Number of seating times: 540,000 times (3,000 cpm x 3 hours) Evaluation item: Valve seat wear amount (shape measurement)

[0093] Table 1 shows that the Vickers hardness at high temperatures (300°C, 400°C) of the slide members of Examples 1 to 5, which are within the scope of the present invention, is higher than the Vickers hardness at high temperatures of the slide members of Comparative Examples 1 to 6, which are outside the present invention. Therefore, Table 1 shows that the slide members of Examples 1 to 4, which are within the scope of the present invention and do not contain any of simple metal particles, alloy particles, or ceramic particles, have superior high-temperature wear resistance compared to the slide members of Comparative Examples 1 to 4, which are outside the present invention and do not contain any of simple metal particles, alloy particles, or ceramic particles. Furthermore, Table 1 shows that the slide member of Example 5, which contains alloy particles and is within the scope of the present invention, has superior high-temperature wear resistance compared to the slide members of Comparative Examples 5 and 6, which contain alloy particles and are outside the present invention.

[0094] The reason why the sliding member of the present invention has excellent high-temperature wear resistance is believed to be that the sliding film contains copper-based alloy particles containing titanium, and has linear titanium oxide layers at parts of the interfaces between the particles that form the sliding film, as shown in FIG. 4 .

[0095] Another reason why the sliding member of the present invention has excellent high-temperature wear resistance is thought to be that the titanium content in the copper-based alloy particles is 3.5% by mass or more and 11.0% by mass or less.

[0096] Furthermore, it is believed that the excellent high-temperature wear resistance of the sliding member of the present invention is due to the copper-based alloy particles containing precipitates of copper and titanium.

[0097] It is also believed that the sliding member of the present invention has excellent high-temperature wear resistance because the sliding film contains the above-mentioned specified metal particles.

[0098] Although the present invention has been described above using a few embodiments, the present invention is not limited to these, and various modifications are possible within the scope of the gist of the present invention. For example, the components described above are not limited to the components shown in each embodiment, and it is possible to change the details of the specifications of the copper-based alloy particles, metal particles, ceramic particles, and sliding film, or to apply the components of each embodiment to other embodiments.

[0099] For example, in the sliding member of the above-described embodiment, the sliding film is formed on the surface of the substrate. However, in the sliding member of the present invention, for example, the entire sliding member may be formed of the above-described sliding film.

[0100] Furthermore, for example, in the internal combustion engine of the above-described embodiment, a sliding member is provided on the seating portion (valve seat) of the engine valve. However, in the internal combustion engine of the present invention, it is sufficient if a sliding member is provided in at least one location, such as the valve face of the engine valve, the valve stem, the valve guide, the valve lifter, the piston, the piston ring, the piston pin, the cylinder, the crankshaft, the camshaft, or the connecting rod.

[0101] REFERENCE SIGNS LIST 1, 2 Sliding member 10 Substrate 20 Sliding film 20a Interface 20b Pores 20c Surface 21 Copper-based alloy particles 23 Titanium oxide layer 25 Metal particles (ceramic particles)

Claims

1. A sliding member having a sliding film on at least a surface thereof, the sliding film includes copper-based alloy particles containing titanium, and has a titanium oxide layer at a part of the interface between the particles forming the sliding film; The titanium content in the copper-based alloy particles is 3.5% by mass or more and 11.0% by mass or less. A sliding member characterized by:

2. (delete)

3. 2. The sliding member according to claim 1, wherein the titanium content in the copper-based alloy particles is 3.5% by mass or more and 9.0% by mass or less.

4. 2. The sliding member according to claim 1, wherein the copper-based alloy particles contain precipitates made of copper and titanium.

5. (delete)

6. 2. The sliding member according to claim 1, wherein the sliding film contains metal particles containing at least one metal selected from the group consisting of iron, cobalt, molybdenum, chromium and nickel, and / or ceramic particles.

7. 2. The sliding member according to claim 1, wherein the porosity in a cross section of the sliding film is 4 area % or less.

8. 2. The sliding member according to claim 1, wherein the sliding film has at least one of an amorphous phase and a nanocrystalline phase at interfaces between particles forming the sliding film.

9. 2. The sliding member according to claim 1, further comprising a substrate, the sliding film being formed on the substrate.

10. 10. The sliding member according to claim 9, wherein the sliding film is formed by spraying particles forming the sliding film onto the base material and deforming the base material.

11. An internal combustion engine comprising the sliding member according to any one of claims 1, 3, 4, and 6 to 10.