JP7026889B2 - Sliding member - Google Patents

Description

The present invention relates to a sliding member.

Conventionally, a sintered alloy for a valve seat having excellent wear resistance and low attack resistance to the opponent has been proposed (see Patent Document 1). In this sintered alloy for valve seats, the hard alloy particles (A), the hard alloy particles (B), the ceramic particles (C), and the CaF ₂ particles (D) are contained in the matrix of the sintered alloy skeleton. A: 20 to 30 wt%, B: 1 to 10 wt%, C: 1 to 10 wt%, D: 0.5 to 7 wt% (A + B + C: less than 40 wt%). In this sintered alloy for valve seats, 10 to 20 wt% of copper or copper alloy is infiltrated into the pores of the sintered alloy skeleton. The sintered alloy skeleton consists of carbon: 1.0 to 1.3 wt%, chromium: 1.5 to 3.4 wt%, and the balance is iron and unavoidable impurities. The hardness of the hard alloy particles (A) is HV500 to 900. The hardness of the hard alloy particles (B) is HV1000 or higher. The hardness of the ceramic particles (C) is HV1500 or higher.

Japanese Unexamined Patent Publication No. 6-179937

However, the sintered alloy for valve seats described in Patent Document 1 has room for improvement in terms of wear resistance.

The present invention has been made in view of the problems of the prior art. An object of the present invention is to provide a sliding member capable of achieving excellent wear resistance.

The present inventors have made extensive studies to achieve the above object. As a result, it has been found that the above object can be achieved by forming a coating layer composed of a plurality of particles bonded to each other and containing predetermined iron-based alloy particles as the plurality of particles on the sliding portion of the base material, and the present invention has been made. It came to be completed.

According to the present invention, it is possible to provide a sliding member having excellent wear resistance.

FIG. 1 is a cross-sectional view schematically showing a sliding member according to the first embodiment. FIG. 2 is an enlarged view of a portion of the sliding member shown in FIG. 1 surrounded by line II. FIG. 3 is a transmission electron microscope image of an example (Example 1) of iron-based alloy particles contained in the coating layer of the sliding member. FIG. 4 is a transmission electron microscope image of another example (Example 2) of the iron-based alloy particles contained in the coating layer of the sliding member. FIG. 5 is a cross-sectional view schematically showing the sliding member according to the second embodiment. FIG. 6 is an enlarged view of a portion of the sliding member shown in FIG. 5 surrounded by a VI line. FIG. 7 is a cross-sectional view schematically showing an example of a valve operating mechanism of an internal combustion engine to which a sliding member is applied. FIG. 8 is a cross-sectional view schematically showing an example of a bearing mechanism of an internal combustion engine to which a sliding member is applied.

Hereinafter, the sliding member according to one embodiment of the present invention will be described in detail with reference to the drawings.

(First form)
First, the sliding member according to the first embodiment will be described in detail with reference to the drawings. The dimensional ratios of the drawings cited in each of the following forms are exaggerated for convenience of explanation and may differ from the actual ratios.

FIG. 1 is a cross-sectional view schematically showing a sliding member according to the first embodiment. Further, FIG. 2 is an enlarged view of a portion of the sliding member shown in FIG. 1 surrounded by line II.

As shown in FIGS. 1 and 2, the sliding member 1 of the first embodiment includes a base material 10 and a coating layer 20 formed on a sliding portion of the base material 10. In the illustrated example, the surface 20a of the coating layer 20 is a sliding surface.

The coating layer 20 is composed of a plurality of particles 30 bonded to each other, and contains iron-based alloy particles 31 as the plurality of particles 30. In the illustrated example, all of the plurality of particles 30 are made of iron-based alloy particles 31. Further, the iron-based alloy particles 31 have either one or both of the nanocrystal structure and the amorphous structure 31A on the particle surface side, and have a core portion 31C on the particle center side.

Here, in the present invention, the "iron-based alloy" means that the component contained most in the alloy is iron.

Further, either one or both 31A of the nanocrystalline structure and the amorphous structure may form a layered portion. The layered portion may be a continuous layer or a discontinuous layer.

Here, in the present invention, the "nanocrystal structure" means a crystal structure having a size on the order of nanometers. Although not particularly limited, the nanocrystal structure preferably has a maximum major axis of crystal grain size of about 10 to 100 nm.

The "maximum major axis" refers to various structures and precipitates when the nanocrystal structure, the amorphous structure described later, the microcrystal structure, the precipitate, etc. are observed using a scanning electron microscope, a transmission electron microscope, or the like. It means the maximum distance between any two points on the contour line of an object. At the time of this observation, energy dispersive X-ray analysis, backscattered electron diffraction analysis and the like may be combined, if necessary.

Further, in the present invention, the "amorphous structure" means an amorphous structure having a size on the order of nanometers, which is similar to that of a nanocrystal structure. Although not particularly limited, the amorphous structure as well as the nanocrystal structure preferably has a maximum major axis of about 10 to 100 nm.

Further, although not shown, the coating layer may have pores.

Although not particularly limited, the core portion 31C preferably contains a microcrystal structure (not shown).

Here, in the present invention, the "microcrystal structure" means a crystal structure having a size on the order of micrometers. Although not particularly limited, the microcrystal structure preferably has a maximum major axis of crystal grain size of about 1 to 10 μm, and more preferably a size of about 1 to 5 μm.
It is considered that strength and toughness can be achieved at the same time by making the structure in which the nanocrystal structure and the microcrystal structure coexist.

Further, FIG. 3 is a transmission electron microscope image of an example of iron-based alloy particles contained in the coating layer of the sliding member (see Example 1). Further, FIG. 4 is a transmission electron microscope image of another example (see Example 2) of the iron-based alloy particles contained in the coating layer of the sliding member.

As shown in FIGS. 3 and 4, the iron-based alloy particles 31 are carbon, a carbide of the constituent elements of the iron-based alloy particles and carbon, and any of the constituent elements of the iron-based alloy particles and a compound of silicon or nitrogen. It contains a precipitate 31B composed of one or both. The precipitate 31B exists in a state of being dispersed in dots in the vicinity of or inside the above-mentioned layered portion. Further, although not particularly limited, the precipitate preferably has a maximum major axis of about 10 to 100 nm.

Here, in the present invention, the "carbide of a constituent element of an iron-based alloy particle and carbon" typically means a carbide of an alloy element which is a typical example of a constituent element of an iron-based alloy particle. Specific examples thereof include chromium carbide, vanadium carbide, tungsten carbide, molybdenum carbide, manganese carbide and the like. However, the present invention is not limited to these, and in the present invention, "carbide of constituent elements of iron-based alloy particles and carbon" also includes iron carbide such as cementite.

Further, in the present invention, the "compound of the constituent elements of the iron-based alloy particles and silicon or nitrogen" means a silicate of the constituent elements of the iron-based alloy particles when the iron-based alloy particles contain silicon. , When the iron-based alloy particles contain nitrogen, it means a nitride of the constituent elements of the iron-based alloy particles, and when the iron-based alloy particles contain silicon and nitrogen, it means the constituent elements of the iron-based alloy particles. Means one or both of the alloys and nitrides of.

Further, although not shown, the iron-based alloy particles may contain carbon in a form other than the carbide. Examples of forms other than carbides include alloys such as a solid solution of carbon and constituent elements of iron-based alloy particles. Further, although not shown, the carbon content in the iron-based alloy particles is 0.08% by mass or more. For example, the carbon content of the carbide refers only to the carbon in the carbide.

Here, the carbon content in the iron-based alloy particles can be measured by, for example, a wavelength dispersive X-ray analysis method. Further, when the coating layer is formed by the cold spray method, the iron-based alloy raw material particles are not dissolved, so that the component composition of the iron-based alloy raw material particles is almost maintained in the iron-based alloy particles.

As described above, since it is a sliding member provided with a predetermined coating layer, it exhibits excellent wear resistance.

Here, the above-mentioned "predetermined coating layer" is composed of a plurality of particles bonded to each other, includes iron-based alloy particles as the plurality of particles, and the iron-based alloy particles have a nanocrystalline structure and an amorphous structure on the particle surface side. Either one or both of the above, and the iron-based alloy particles are carbon, a carbide of the constituent elements of the iron-based alloy particles and carbon, and either one or a compound of the constituent elements of the iron-based alloy particles and silicon or nitrogen. It contains precipitates composed of both, and has a carbon content of 0.08% by mass or more in the iron-based alloy particles.

The sliding member provided with the predetermined coating layer can be formed by, for example, a cold spray method. On the other hand, in the thermal spraying method and the sintering method, a sliding member having a predetermined coating layer cannot be obtained.

Further, in SUS316L and SUS304L defined in Japanese Industrial Standards G4303, which are generally used as austenitic stainless steel, the carbon content is less than 0.08% by mass. When such iron-based alloy raw material particles are used, the wear resistance of the sliding member cannot be improved even by the cold spray method.

The present inventors have obtained the following technical knowledge about a hard film formed by a cold spray method using the above-mentioned iron-based alloy raw material particles.

Since such a hard film causes work hardening and work-induced transformation that are easily recovered by heat, the amount of wear is large when applied to a portion having a high heat load such as a valve seat.

At present, it is considered that the effect of improving wear resistance is obtained for the following reasons.

The iron-based alloy raw material particles are supersaturated solid solutions having a crystal grain size on the order of micrometers. The iron-based alloy raw material particles sprayed onto the base material by the cold spray device collide with the base material or the iron-based alloy particles adhering to the base material, and a strong force is applied to cause a phenomenon called a material jet. At that time, a diffusion layer is formed between the surrounding base material and other iron-based alloy particles. The periphery of this diffusion layer is in a state of being strongly processed and exposed to rapid heat and quenching. As a result, the size of the crystal grain size becomes fine, and a nanocrystal structure or an amorphous structure is formed. Further, the iron-based alloy raw material particles contain a certain amount of carbon. Therefore, when the coating layer is formed by cold spraying, precipitates composed of carbides of the constituent elements of the iron-based alloy particles are generated in a point-like state in the vicinity of the nanocrystal structure and the amorphous structure. When the iron-based alloy raw material particles contain silicon or nitrogen, the constituent elements of the iron-based alloy particles are located in the vicinity of the nanocrystalline structure or the amorphous structure when the coating layer is formed by cold spraying. It is produced in a state where precipitates composed of a compound of silicon or nitrogen are dispersed in dots. The formation of precipitates in the iron-based alloy particles increases the strength of the coating layer. As a result, the wear resistance of the coating layer is improved.

However, it goes without saying that even if the above-mentioned effects are obtained for reasons other than the above-mentioned reasons, they are included in the scope of the present invention.

Here, each component will be described in more detail.

The base material 10 is not particularly limited, but is preferably a metal that can be applied to a method for manufacturing a sliding member, that is, a method for forming a coating layer, which will be described in detail later. Needless to say, it is preferable that the base material can be used in a high temperature environment to which the sliding member is applied when the sliding member is applied to the internal combustion engine.

As the metal, for example, conventionally known alloys such as aluminum, iron, titanium, and copper are preferably applied.

Further, as the aluminum alloy, for example, AC2A, AC8A, ADC12 and the like specified in Japanese Industrial Standards are preferably applied. Further, as the iron alloy, for example, SUS304 specified in Japanese Industrial Standards, an iron-based sintered alloy, or the like is preferably applied. Further, as the copper alloy, for example, beryllium copper, a copper alloy-based sintered alloy, or the like is preferably applied.

The porosity of the coating layer 20 is preferably 5 area% or less. For example, from the viewpoint that if the porosity of the coating layer is large, the strength is insufficient and the wear resistance may be lowered, it is preferable that the porosity of the coating layer is as small as possible. At present, it is possible to reduce the pore ratio of the coating layer to 0.1 area%, so from the viewpoint of achieving excellent wear resistance and improved productivity in a well-balanced manner. The pore ratio of the coating layer is preferably 0.1 to 5 area%, more preferably 0.1 to 2.00 area%, still more preferably 0.5 to 1.75 area. , 0.5 to 1.50 area% is particularly preferable. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited. Further, the pore ratio in the cross section of the coating layer can be calculated by, for example, observing a scanning electron microscope image of the cross section of the coating layer and image processing such as binarization of the cross-section scanning electron microscope image.

Further, the coating layer is not particularly limited in terms of its thickness. That is, the thickness of the coating layer may be appropriately adjusted depending on the temperature of the applied portion and the sliding environment. For example, the thickness of the coating layer is preferably 0.05 to 5.0 mm, more preferably 0.1 to 2.0 mm. If the thickness of the coating layer is less than 0.05 mm, the rigidity of the coating layer itself is insufficient, and therefore, plastic deformation may occur especially when the strength of the base material is low. Further, if the thickness of the coating film is more than 10 mm, the coating film may be peeled off due to the relationship between the residual stress generated at the time of film formation and the interfacial adhesion.

The iron-based alloy particles 31 have either or both of a nanocrystalline structure and an amorphous structure on the surface side of the particles, and are carbonized carbon, a constituent element of the iron-based alloy particles, and carbon, and iron-based alloy particles. It is not particularly limited as long as it contains a precipitate consisting of one or both of the constituent elements of the above and silicon or nitrogen, and the carbon content in the iron-based alloy particles is 0.08% by mass or more. do not have. Typical examples of iron-based alloys are high-speed tool steels specified in Japan Industrial Standard G4403, martensitic stainless steels specified in Japan Industrial Standard G4303, and alloy tool steels specified in Japan Industrial Standard G4404. Can be mentioned.

Further, although not particularly limited, the carbon content in the iron-based alloy such as steel is preferably 1.5% by mass or less from the viewpoint of improving wear resistance. Further, although not particularly limited, from the viewpoint of improving wear resistance, the carbon content in the iron-based alloy such as steel is more preferably 0.35 to 1.5% by mass, and is 0. It is more preferably .8 to 1.5% by mass. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, the content of chromium in an iron-based alloy such as steel is preferably 0.20% by mass or more. When the content of chromium in an iron-based alloy such as steel is 0.20% by mass or more, chromium carbide that contributes to the improvement of wear resistance is likely to be formed. Although not particularly limited, the content of chromium in an iron-based alloy such as steel is more preferably 3 to 20% by mass from the viewpoint of improving wear resistance. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, it is preferable that the iron-based alloy such as steel contains vanadium, tungsten, molybdenum, and manganese. When vanadium, tungsten, molybdenum, manganese and the like are contained in an iron-based alloy such as steel, these carbides that contribute to the improvement of wear resistance are likely to be formed. These may contain one kind alone or may contain two or more kinds in an appropriate combination. However, it is not limited to these, and it goes without saying that these elements may not be contained as long as the effects of the present invention can be exhibited.

Further, although not particularly limited, the content of vanadium in an iron-based alloy such as steel is preferably 0.9 to 5.20% by mass. When the content of vanadium in the iron-based alloy such as steel is 0.9 to 5.20% by mass, vanadium carbide that contributes to the improvement of wear resistance is likely to be formed. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, the content of the tungsten content in the iron-based alloy such as steel is preferably 1.20 to 19.0% by mass. When the content of tungsten in an iron-based alloy such as steel is 1.20 to 19.0% by mass, tungsten carbide that contributes to the improvement of wear resistance is likely to be formed. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, the content of molybdenum in an iron-based alloy such as steel is preferably 1 to 6% by mass. When the content of molybdenum in an iron-based alloy such as steel is 1 to 6% by mass, molybdenum carbide that contributes to the improvement of wear resistance is likely to be formed. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, the content of manganese in an iron-based alloy such as steel is preferably 0.2 to 3% by mass. When the content of manganese in the iron-based alloy such as steel is 0.2 to 3% by mass, manganese carbide that contributes to the improvement of wear resistance is likely to be formed. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, although not particularly limited, the Vickers hardness of the iron-based alloy particles (base) such as steel is preferably 400 HV or more, and more preferably 450 HV or more, from the viewpoint of improving wear resistance. It is more preferably 500 HV or more, and particularly preferably 600 HV or more. Further, in consideration of productivity, the Vickers hardness of the iron-based alloy particles (base) is preferably 1500 HV or less, more preferably 1000 HV or less, still more preferably 750 HV or less. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited.

The Vickers hardness of iron-based alloy particles (bases) such as steel can be measured and calculated in accordance with the Vickers hardness test (Japanese Industrial Standards Z2244) defined by Japanese Industrial Standards. Further, in determining the measurement position, observation of a scanning electron microscope image or a transmission electron microscope image of the coating layer can be used. At the time of this observation, energy dispersive X-ray analysis, backscattered electron diffraction analysis and the like may be combined, if necessary.

(Second form)
Next, the sliding member according to the second embodiment will be described in detail with reference to the drawings. In addition, the same reference numerals are given to the equivalents as described in the above-described embodiment, and the description thereof will be omitted.

FIG. 5 is a cross-sectional view schematically showing the sliding member according to the second embodiment. Further, FIG. 6 is an enlarged view of a portion of the sliding member shown in FIG. 5 surrounded by a VI line.

As shown in FIGS. 5 and 6, in the sliding member 2 of the second embodiment, the coating layer 20 has a plurality of particles 30 as the iron-based alloy particles 31, as well as the copper-based alloy particles 32 and the cobalt-based alloy particles 33. It is different from the sliding member 1 of the first embodiment in that it contains.

As described above, since it is a sliding member provided with a predetermined coating layer, it exhibits excellent wear resistance.

Although not shown, it goes without saying that the case where only one of the copper-based alloy particles and the cobalt-based alloy particles is contained in addition to the iron-based alloy particles is included in the scope of the present invention.

Although not shown, either one or both of the copper-based alloy particles and the cobalt-based alloy particles may have either or both of the nanocrystalline structure and the amorphous structure on the particle surface side. Needless to say, the case of including such copper-based alloy particles and cobalt-based alloy particles is included in the scope of the present invention.

Here, the copper-based alloy particles and the cobalt-based alloy particles will be described in more detail. In the present invention, the "copper-based alloy" and the "cobalt-based alloy" mean that the components contained most in the alloy are copper and cobalt, respectively.

Examples of the copper-based alloy include precipitation hardening copper alloys such as Corson alloy. Thereby, excellent wear resistance can be realized.

Examples of the cobalt-based alloy include a hard cobalt-based alloy such as TRIBAROY (registered trademark) T-400 and a hard cobalt-based alloy such as Stellite (registered trademark) 6. Thereby, excellent wear resistance can be realized.

In the coating layer, the ratio of iron-based alloy particles is preferably 50 area% or more and 100 area% or less. For example, if the ratio of the iron-based alloy particles in the coating layer is smaller than 50 area%, the strength may be insufficient depending on the types of other particles to be mixed, and the wear resistance may be lowered. At present, it is possible to reduce the porosity of the coating layer to 0.1 area%, so from the viewpoint that excellent wear resistance and productivity improvement can be achieved in a well-balanced manner. The ratio of the iron-based alloy particles is preferably 50 to 99.90 area%, more preferably 50 to 99.50 area%, and even more preferably 70 to 99.50 area%. Further, when the coating layer is composed of only iron-based alloy particles, the ratio of the iron-based alloy particles is preferably 98.50 to 99.90 area%. However, it is not limited to such a range, and it goes without saying that the range may be out of this range as long as the effect of the present invention can be exhibited. Further, the ratio of the iron-based alloy particles in the cross section of the coating layer is calculated by, for example, observing a scanning electron microscope image of the cross section in the coating layer and image processing such as binarization of the cross-section scanning electron microscope image. be able to. At the time of this observation, energy dispersive X-ray analysis, backscattered electron diffraction analysis and the like may be combined, if necessary.

Next, a specific application example of the sliding member according to the first or second embodiment described above will be described in detail with reference to the drawings. A valve valve mechanism of an internal combustion engine to which a sliding member is applied will be described in detail as an example, but the present invention is not particularly limited. Needless to say, the surface of the coating layer is used as a sliding surface. It should be noted that the same reference numerals as those described above are given and the description thereof will be omitted.

FIG. 7 is a cross-sectional view schematically showing an example of a valve operating mechanism of an internal combustion engine to which a sliding member is applied. More specifically, it is a cross-sectional view schematically showing a valve operating mechanism including an engine valve. As shown in FIG. 7, when the cam lob 40 rotates, the valve lifter 41 is pushed down while compressing the valve spring 42, and at the same time, the engine valve 43 is guided by the valve guide 45 having the stem seal 44 and pushed down, and the cylinder head 46 is pushed down. The engine valve 43 is separated from the seating portion 46A of the engine valve 43 in the above, and the exhaust port 47 and the combustion chamber (not shown) communicate with each other (the open state of the engine valve). After that, when the cam lob 40 further rotates, the repulsive force of the valve spring 42 pushes up the engine valve 43 together with the valve lifter 41, the retainer 48, and the cotter 49, and the engine valve 43 comes into contact with the seating portion 46A and is not shown as the exhaust port 47. Shut off the combustion chamber (engine valve closed). Such opening and closing of the engine valve 43 is performed in synchronization with the rotation of the cam lob 40. In this way, the valve stem 43A of the engine valve 43 passes through the valve guide 45 press-fitted to the cylinder head 46 side and is incorporated while being oil-lubricated. Further, the valve face 43B of the engine valve 43, which corresponds to the on-off valve portion of the combustion chamber (not shown), is in contact with or non-contact with the 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. 7, the sliding member of the present invention can also be applied to the intake port side (not shown).

Then, a sliding member having the above-mentioned coating layer formed on the sliding surface 46a of the seating portion 46A of the engine valve in the cylinder head, which is a sliding portion of the cylinder head and the engine valve, for example, the above-mentioned first or second. The sliding member (1, 2) in the form of is applied. As a result, it has excellent wear resistance as compared with a sliding member having a coating layer obtained by sintering treatment. Further, by applying the sliding member of the present invention to the cylinder head, it is possible to eliminate the press-fit type valve seat. As a result, it is possible to liberalize the shapes of the exhaust port and the intake port and increase the diameter of the engine valve, and it is possible to improve the fuel efficiency, output, torque, etc. of the engine.

Further, for example, although not shown, on one or both of the sliding surface of the valve stem and the sliding surface of the valve guide which is the mating material, and / or the sliding surface of the valve stem shaft end and the sliding surface of the valve face. A sliding member having the above-mentioned coating layer formed on at least one place selected from the group consisting of the sliding surfaces of the press-fit type valve seat, for example, the sliding member in the above-mentioned first or second form. It can also be applied. As a result, it has excellent wear resistance as compared with a sliding member having a coating layer obtained by sintering treatment.

That is, it is preferable that the cylinder head has the sliding member of the above-mentioned form in the seating portion of the engine valve. Further, the other cylinder head is preferably a cylinder head provided with a valve seat having the above-mentioned sliding member, and the sliding member is preferably provided at the seating portion of the engine valve of the valve seat. Further, it is preferable that the valve seat has the sliding member of the above-mentioned form in the seating portion of the engine valve. Further, it is preferable that the engine valve has the sliding member of the above-mentioned form on the valve face. Further, it is preferable that the other engine valve has the sliding member of the above-mentioned form at the sliding portion with the valve guide.

Further, a specific application example of the sliding member according to the first or second embodiment described above will be described in detail with reference to the drawings. Needless to say, the surface side of the coating layer is used as a sliding surface. Further, the same reference numerals as those described in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 8 is a cross-sectional view schematically showing an example of a bearing mechanism of an internal combustion engine to which a sliding member is applied. More specifically, it is a cross-sectional view schematically showing a bearing mechanism including a bearing metal which is a sliding member of a connecting rod. As shown in FIG. 8, the large end portion 60A on the crank side of the connecting rod 60 (not shown) is divided into upper and lower parts. A bearing metal 62 divided into two for receiving the crankpin 61 is arranged at the large end portion 60A.

Then, as the bearing metal 62, the sliding member on which the coating layer described above is formed, for example, the sliding member (1, 2) in the first or second form described above is applied to the sliding surface 62a. There is. As a result, it has excellent wear resistance as compared with a sliding member having a coating layer obtained by sintering treatment.

Further, for example, although not shown, a sliding member having the above-mentioned coating layer formed on the sliding surface of the bearing metal divided into two for receiving the piston pin at the small end portion on the piston side (not shown) of the connecting rod, for example. , The sliding member in the first or second embodiment described above can also be applied. As a result, it has excellent wear resistance as compared with a sliding member having a coating layer obtained by sintering treatment.

That is, it is preferable that the bearing mechanism of the internal combustion engine has the sliding member of the above-mentioned form in the bearing metal of the bearing mechanism of the internal combustion engine. It is also possible to form a film directly on the sliding surface on the large end side of the connecting rod (form directly without using metal). Further, it is also possible to form a film directly on the sliding surface on the small end side of the connecting rod (form directly without using metal).

The sliding member can also be applied to a piston ring or a piston. That is, it is preferable to apply the coating layer to the surface of the piston ring. Further, it is preferable to apply the coating layer to the inner surface of the ring groove of the piston. Further, as the sliding member, it is preferable to apply the coating layer to the inner surface of the cylinder bore (which can be used as a substitute for a cylinder liner or a substitute for thermal spraying of a bore). Further, for the sliding member, it is preferable to apply the coating layer to the metal of the journal of the crankshaft. Further, for the sliding member, it is preferable to form a film layer directly on the metal portion of the journal of the crankshaft (the film layer is directly formed without using metal). Further, as the sliding member, it is preferable to apply the coating layer to the metal surface of the journal of the camshaft. Further, for the sliding member, it is preferable to form a film layer directly on the metal portion of the journal of the camshaft (the film layer is directly formed without using metal). Further, as the sliding member, it is preferable to apply the coating layer to the cam lob surface of the cam shaft. Further, for the sliding member, it is preferable to apply the coating layer to the metal of the piston and the piston pin. Further, it is preferable that the coating film layer is directly formed on the metal portions of the piston and the piston pin of the sliding member. Further, for the sliding member, it is preferable to apply the coating layer to the surface of the piston skirt. Further, as the sliding member, it is preferable to apply the coating layer to the crown surface of the valve lifter. Further, for the sliding member, it is preferable to apply the coating layer to the side surface of the valve lifter. Further, as the sliding member, it is preferable to apply the coating layer to the sliding surface of the cylinder head with the valve lifter of the lift turbo. Further, the sliding member may apply the coating layer to the tooth surface of the sprocket (at this time, for example, forming the coating layer on the sprocket of the aluminum sintered alloy instead of the sprocket of the iron sintered alloy). preferable. Further, as for the sliding member, it is preferable to apply the coating layer to the pin of the chain. Further, for the sliding member, it is preferable to apply the coating layer to the chain plate.

Further, in the sliding member in the first or second embodiment described above, the coating layer is formed on the surface of the teeth of a gear other than the internal combustion engine (at this time, for example, a steel gear is made into an aluminum alloy, and the coating layer is formed on the aluminum alloy. It is preferable to apply to.). Here, examples of non-internal combustion engines include differential gears of automobiles, generators of automobiles, and generators other than automobiles. Further, the sliding member in the first or second form described above is preferably applied to all sliding bearings (sliding bearings in a broad sense that are not rolling bearings).

Next, a method of manufacturing the sliding member will be described in detail. The method for manufacturing a sliding member is, for example, a method for manufacturing a sliding member having a base material in the above-mentioned form and a predetermined coating layer formed on the base material. The method for manufacturing this sliding member is to prepare iron-based alloy raw material particles or a mixture containing iron-based alloy raw material particles and one or both of copper-based alloy raw material particles and cobalt-based alloy raw material particles in a non-melted state. It comprises a step of spraying onto a substrate to form a predetermined coating layer on the substrate.

As described above, the iron-based alloy raw material particles or the mixture in a non-melted state are sprayed onto the base material to form a predetermined coating layer on the base material, thereby forming a coating layer having excellent wear resistance. It can be formed efficiently. In other words, by forming the coating layer by a method called kinetic spray, cold spray, worm spray or the like, the coating layer having excellent wear resistance can be efficiently formed. However, the sliding member of the present invention is not limited to the one manufactured by such a manufacturing method.

Here, a more specific manufacturing method will be described in more detail.

As described above, when the iron-based alloy raw material particles or the mixture are sprayed onto the base material, the iron-based alloy raw material particles or the mixture are applied at a rate of forming a plastically deformed portion on at least one of the base material and the coating layer. It is preferable to spray it on the material. As a result, a coating layer having more excellent wear resistance can be efficiently formed.

For example, the pressure of the working gas supplied for spraying the iron-based alloy raw material particles or the mixture is preferably 0.5 to 5 MPa, more preferably 0.8 to 4 MPa, and 0.8 to 3.5 MPa. Is more preferable. If the pressure of the working gas is less than 0.5 MPa, the particle velocity cannot be obtained and the porosity may increase. However, it is needless to say that the range is not limited to such a range, and the range may be out of this range as long as the effect of the present invention can be exhibited.

The temperature of the working gas is not particularly limited, but is preferably 400 to 800 ° C, more preferably 600 to 800 ° C, for example. If the temperature of the working gas is less than 400 ° C., the porosity may increase and the wear resistance may decrease. Further, if the temperature of the working gas exceeds 800 ° C., nozzle clogging may occur. However, it is needless to say that the range is not limited to such a range, and the range may be out of this range as long as the effect of the present invention can be exhibited.

Further, the type of the working gas is not particularly limited, and examples thereof include nitrogen and helium. These may be used individually by 1 type, and may be used in combination of a plurality of types such as main gas and carrier gas. Further, the fuel gas and nitrogen may be mixed and used.

Further, the iron-based alloy raw material particles or the mixture are not particularly limited, but are preferably in the state of a supersaturated solid solution, for example. Since it is in the state of a supersaturated solid solution, it has a large ductility, in other words, it has a deformability, so that a coating film layer can be efficiently formed and the film forming property can be improved. Here, the raw material particles in the state of a supersaturated solid solution are not particularly limited, but for example, it is preferable to apply the quenching solidified particles obtained by quenching and solidifying by an atomizing method or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)
SKH51 (manufactured by Daido Special Steel Co., Ltd., trade name: DAPMH51, classification: SKH material / high-speed steel, component: Fe-0.85C-4Cr-5Mo-) specified in Japanese Industrial Standards G4403 as raw material particles for iron-based alloys. 6W-2V, particle size: -20 μm) was prepared. In addition, "particle size: -20 μm" means that the particle diameter is 20 μm or less (the same applies hereinafter). Further, as the "particle diameter" when measuring and calculating such a particle size, for example, the above-mentioned "maximum major axis", specifically, any two points on the contour line of the observed particle (observation surface). The maximum distance between them was adopted.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a cold spray device (Kinetic Metallization, gas manufactured by Inovati). Seed: He, gas pressure: 0.8 MPa, gas temperature: 600 ° C.) was used to spray to form a coating layer having a coating layer thickness of 1.0 mm on the substrate.

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained. The thickness of the coating layer is 0.5 mm (the same applies hereinafter).

(Example 2)
As iron-based alloy raw material particles, SUS440C (manufactured by Daido Special Steel Co., Ltd., trade name: DAP440C, classification: martensitic SUS, component: Fe-1.1C-0.5Si-0. 5Mn-17Cr, particle size: −20 μm) was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a cold spray device (Kinetic Metallization, gas manufactured by Inovati). Seed: He, gas pressure: 0.8 MPa, gas temperature: 600 ° C.) was used to spray to form a coating layer having a coating layer thickness of 1.0 mm on the substrate.

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Example 3)
SUS420J2 (manufactured by Daido Special Steel Co., Ltd., trade name: DAP420J2, classification: martensitic SUS, component: Fe-0.35C-13Cr, particle size: -30 μm) specified in Japanese Industrial Standards G4303 as raw material particles for iron-based alloy. ) Was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a high-pressure cold spray device (Kintics 4000, manufactured by CGT). A coating layer having a coating layer thickness of 1.0 mm was formed on the substrate by spraying using a gas type: N ₂ , gas pressure: 3.5 MPa, gas temperature: 750 ° C.).

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Example 4)
As iron-based alloy raw material particles, SKD61 (manufactured by Daido Steel Co., Ltd., trade name: DAPDHA1, classification: SKD material, component: Fe-0.35C-5Cr-1.25Mo-1V, specified in Japanese Industrial Standards G4404, Particle size: -30 μm) was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a high-pressure cold spray device (Kintics 4000, manufactured by CGT). A coating layer having a coating layer thickness of 1.0 mm was formed on the substrate by spraying using a gas type: N ₂ , gas pressure: 3.5 MPa, gas temperature: 750 ° C.).

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Example 5)
SKH51 (manufactured by Daido Special Steel Co., Ltd., trade name: DAPMH51, classification: SKH material / high-speed steel, component: Fe-0.85C-4Cr-5Mo-) specified in Japanese Industrial Standards G4303 as raw material particles for iron-based alloys. 6W-2V, particle size: -20 μm) was prepared. Further, Cu—Ni—Si alloy (classification: copper alloy (Corson alloy), component: Cu-3Ni—0.7Si, particle size: -30 μm) was prepared as the raw material particles for the copper-based alloy. Further, as the cobalt-based alloy raw material particles, a Co alloy (manufactured by Kennametal Stellite, trade name: Tribaloy T-400, classification: Co alloy, component: Co-28Mo-8Cr-2.5Si, particle size: -45 μm) was prepared. .. Further, these were mixed to prepare mixed raw material particles.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material is mounted on the rotary table, and the prepared mixed raw material particles are placed on the prepared aluminum base material while rotating the rotary table (CGT, Kinetics 4000, gas type). : N ₂ , gas pressure: 3.5 MPa, gas temperature: 750 ° C.) was used to form a coating layer having a coating layer thickness of 1.0 mm on the substrate.

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Comparative Example 1)
SUS316L (manufactured by Daido Special Steel Co., Ltd., trade name: DAP316L, classification: austenitic SUS, component: Fe-0.02C-17Cr-13Ni-2Mo-0) specified in Japanese Industrial Standards G4303 as raw material particles for iron-based alloys. .9Si, particle size: -30 μm) was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a high-pressure cold spray device (Kintics 4000, manufactured by CGT). A coating layer having a coating layer thickness of 1.0 mm was formed on the substrate by spraying using a gas type: N ₂ , gas pressure: 3.5 MPa, gas temperature: 750 ° C.).

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Comparative Example 2)
As raw material particles for iron-based alloy, SUS304L specified in Japanese Industrial Standards G4303 (manufactured by Daido Special Steel Co., Ltd., trade name: DAP304L, classification: austenitic SUS, component: Fe-0.02C-19Cr-11Ni, particle size:- 30 μm) was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a high-pressure cold spray device (Kintics 4000, manufactured by CGT). A coating layer having a coating layer thickness of 1.0 mm was formed on the substrate by spraying using a gas type: N ₂ , gas pressure: 3.5 MPa, gas temperature: 750 ° C.).

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Comparative Example 3)
Fe—Si—B—Cr-based amorphous particles (classification: amorphous iron-based alloy, component: Fe—Si—B—Cr, particle size: −20 μm) were prepared as iron-based alloy raw material particles.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared iron-based alloy raw material particles were placed on the prepared aluminum base material with a cold spray device (Kinetic Metallization, gas manufactured by Inovati). Seed: He, gas pressure: 0.8 MPa, gas temperature: 600 ° C.) was used to spray to form a coating layer having a coating layer thickness of 1.0 mm on the substrate.

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Comparative Example 4)
As cobalt-based alloy raw material particles, CoNiCrAlY (manufactured by Inovati, trade name: KMCoNiCrAlY powder, classification: cobalt-based alloy, component: Co-32Ni-21Cr-8Al-0.5Y, particle size: -22 μm) was prepared.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared cobalt-based alloy raw material particles were placed on the prepared aluminum base material with a cold spray device (Kinetic Metallization, gas manufactured by Inovati). Seed: He, gas pressure: 0.8 MPa, gas temperature: 600 ° C.) was used to spray to form a coating layer having a coating layer thickness of 1.0 mm on the substrate.

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained.

(Comparative Example 5)
Cu—Ni—Si alloy (classification: copper alloy (Corson alloy), component: Cu-3Ni—0.7Si, particle size: -30 μm) was prepared as the raw material particles for the copper-based alloy.

With the processing of the seating part of the engine valve in the cylinder head completed, pre-processing the aluminum base material (Japanese Industrial Standards H4040A5056) is performed assuming a target coating layer thickness of 0.5 mm, and the pre-processed aluminum base material is used. I prepared it.

Next, the prepared aluminum base material was attached to the rotary table, and while rotating the rotary table, the prepared copper-based alloy raw material particles were placed on the prepared aluminum base material with a high-pressure cold spray device (Kintics 4000, manufactured by CGT). A coating layer having a coating layer thickness of 1.0 mm was formed on the substrate by spraying using a gas type: N ₂ , gas pressure: 4 MPa, gas temperature: 600 ° C.).

After that, by machining, the shape of the seating portion of the engine valve in the actual cylinder head was finished, and the sliding member of this example was obtained. Tables 1 to 4 show some of the specifications of each example.

Here, in Tables 3 and 4, the presence / absence of nanocrystal structure, the presence / absence of amorphous structure, the presence / absence and details of precipitates, the presence / absence of microcrystal structure, and the ratio of each particle or pore in the coating layer are scan type. It was identified by observation using an electron microscope and a transmission electron microscope, energy dispersive X-ray analysis, and backscattered electron diffraction analysis.

Further, in Tables 3 and 4, the Vickers hardness of iron-based alloy particles (bases) and the like was measured and calculated in accordance with the Vickers hardness test (Japanese Industrial Standard Z2244) specified by Japanese Industrial Standards. The number of measurements was set to 10 in order to obtain the arithmetic mean value. In determining the measurement position, the results of observation of scanning electron microscope images and transmission electron microscope images of the coating layer, energy dispersive X-ray analysis, backscattered electron diffraction analysis, and the like were used.

[Performance evaluation]
The wear resistance of the sliding members of each of the above examples was evaluated as follows.

(Abrasion resistance)
The amount of wear was measured and calculated under the following test conditions using a valve seat wear tester manufactured by Takachiho Seiki Co., Ltd. Specifically, the shape of the seated portion of the engine valve in the cylinder head before and after the test is acquired using a shape measuring device, the amount of wear at four points is measured, the average value is calculated, and this is worn. The amount was taken. The obtained results are also shown in Tables 3 and 4.

From Tables 3 and 4, it can be seen that Examples 1 to 5 belonging to the scope of the present invention have better wear resistance than Comparative Examples 1 to 5 outside the scope of the present invention.

It is considered that this is because the sliding member is provided with the above-mentioned predetermined coating layer. Specifically, the coating layer contains iron-based alloy particles having either or both of a nanocrystalline structure and an amorphous structure on the particle surface side, and the iron-based alloy particles contain carbon and carbides, and the iron-based alloy. It is considered that the carbon content in the particles is 0.08% by mass or more.

Further, it is the above-mentioned predetermined coating layer that Examples 1 to 5 belonging to the scope of the present invention have better wear resistance than Comparative Examples 1 to 5 outside the scope of the present invention. It is also considered that the sliding member is provided, and the content of chromium in the iron-based alloy particles is 0.20% by mass or more. Furthermore, it is also considered that the iron-based alloy particles contain chromium carbides.

Further, it is provided with the above-mentioned predetermined coating layer that Examples 1, 4 and 5 belonging to the scope of the present invention have better wear resistance than Examples 2 and 3. It is also considered that the sliding member is a sliding member, the chromium content in the iron-based alloy particles is 0.20% by mass or more, and the iron-based alloy particles contain vanadium, tungsten, and the like. Furthermore, it is also considered that the iron-based alloy particles contain carbides such as chromium, vanadium, and tungsten.

Further, it is the sliding member provided with the above-mentioned predetermined coating layer that the examples 1 and 5 belonging to the scope of the present invention have better wear resistance than the examples 2 to 4. Further, the content of chromium in the iron-based alloy particles is 0.20% by mass or more, the iron-based alloy particles contain vanadium, tungsten, etc., and further, the content of vanadium in the iron-based alloy particles is high. It is considered that the content is 0.90 to 5.20% by mass and the content of tungsten is 1.20 to 19.0% by mass. Furthermore, it is also considered that the iron-based alloy particles are high-speed tool steel specified in Japanese Industrial Standard G4403 containing carbides such as chromium, vanadium, and tungsten.

Further, it is the above-mentioned predetermined coating layer that Examples 1 to 5 belonging to the scope of the present invention have better wear resistance than Comparative Examples 1 to 5 outside the scope of the present invention. It is also considered that the sliding member is provided and the porosity of the coating layer is 5 area% or less.

Further, it is the above-mentioned predetermined coating layer that Examples 1 to 5 belonging to the scope of the present invention have better wear resistance than Comparative Examples 1 to 5 outside the scope of the present invention. It is also considered that the iron-based alloy particles have a core portion containing a microcrystal structure on the particle center side.

Further, it is the sliding member provided with the above-mentioned predetermined coating layer that the Example 5 belonging to the scope of the present invention has better wear resistance than the Example 1, and the coating layer further comprises. It is also considered that the plurality of particles include one or both of the copper-based alloy particles and the cobalt-based alloy particles.

Further, it is the sliding member provided with the above-mentioned predetermined coating layer that the Example 2 belonging to the scope of the present invention has better wear resistance than the Example 3, and further, the iron-based alloy particles. Is also thought to be due to the inclusion of silicon. Furthermore, it is also considered that the iron-based alloy particles contain chromium silicate.

Although the present invention has been described above with some embodiments and examples, the present invention is not limited thereto, and various modifications can be made within the scope of the gist of the present invention.

1, 2 Sliding member 10 Base material 20 Coating layer 20a Surface 30 Particles 31 Iron-based alloy particles 31A Nanocrystalline structure and / or amorphous structure (layered part)
31B Precipitate 31C Core 32 Copper-based alloy particles 33 Cobalt-based alloy particles

Claims (8)

A sliding member including a base material and a coating layer formed on a sliding portion of the base material.
The coating layer is composed of a plurality of particles bonded to each other, and contains iron-based alloy particles as the plurality of particles.
The iron-based alloy particles have a nanocrystalline structure and / or an amorphous structure on the surface side of the particles.
The iron-based alloy particles contain carbon and a carbide of the constituent elements of the iron-based alloy particles and carbon, and / or a precipitate composed of a constituent element of the iron-based alloy particles and a compound of silicon or nitrogen. A sliding member having a carbon content of 0.08% by mass or more in iron-based alloy particles. The sliding member according to claim 1, wherein the iron-based alloy particles contain chromium and the chromium content is 0.20% by mass or more. The sliding member according to claim 2, wherein the iron-based alloy particles contain at least one selected from the group consisting of vanadium, tungsten, molybdenum, and manganese. The iron-based alloy particles contain vanadium and tungsten, and the vanadium content is 0.90 to 5.20% by mass, and the tungsten content is 1.20 to 19.0% by mass. The sliding member according to claim 3. The sliding member according to any one of claims 1 to 4, wherein the coating layer has pores and the porosity of the coating layer is 5 area% or less. The sliding member according to any one of claims 1 to 5, wherein the iron-based alloy particles have a core portion containing a microcrystal structure on the center side of the particles. The sliding member according to any one of claims 1 to 6, wherein the coating layer contains copper-based alloy particles and / or cobalt-based alloy particles as the plurality of particles. The sliding member according to any one of claims 1 to 3, wherein the iron-based alloy particles contain silicon.

Images