GB2492228A

GB2492228A - A slide memeber with improved resistance to fagtiue and seizur

Info

Publication number: GB2492228A
Application number: GB1210977.3A
Authority: GB
Inventors: Ryo Sato; Naohisa Kawakami; Moritaka Fukuda; Tadatoshi Nagasaki
Original assignee: Daido Metal Co Ltd
Current assignee: Daido Metal Co Ltd
Priority date: 2011-06-21
Filing date: 2012-06-20
Publication date: 2012-12-26
Anticipated expiration: 2032-06-20
Also published as: DE102012210382A1; JP5707245B2; JP2013002613A; DE102012210382B4; GB201210977D0; KR101373683B1; KR20120140614A; GB2492228B

Abstract

The present invention provides a slide member comprising: a first layer 2 mainly containing a first metal having thermal conductivity of 200 to 450 W/(mK) at room temperature to 450 K (177Â°C); a second layer 3 mainly containing a second metal having lower hardness than the first metal; and a third layer 4 provided between the first layer 2 and the second layer 3. The third layer 4 contains the first metal 5 as a parent phase and the second metal 6 as a secondary phase, an area ratio of the secondary phase in the third layer 4 being 10% to 30%, and a thickness of the third layer 4 being 3% or more of a total thickness of the third layer 4 and the first layer 2. There may also be a fourth layer 7 present between the second layer 3 and the third layer 4, the fourth layer including a fifth layer 8 and a sixth layer 9. The sixth layer 9 is composed of a group of minute intermetallic compound particles 10 and is distributed in a strip shape.

Description

SLIDE MEMBER

Background of the invention

(1) Field of the invention

The present invention relates to a slide member with improved fatigue resistance and seizure resistance. . +

(2) Description of related art

Conventionally, a Sn-based alloy or an Al-Sn alloy or the like is used as a bearing alloy in a bearing for a large diesel engine of, for example, a ship. In recent years, with increasing size and output of a diesel engine, a slide member, of a bearing etc. is exposed to severer environments. However, a conventional Sn-based alloy has low strength and easily causes fatigue failure. And also, the Al-Sn alloy more easily causes seizure than the Sn-based alloy. Thus, a slide member having high fatigue resistance and seizure resistance is desired.

As a means to solve the above problem, it is considered to be effective that a Sn-based alloy layer having high seizure resistance is placed on an Al alloy layer having high fatigue resistance to form a multilayer structure. Such a muttilayer structure has been conventionally proposed. For example, JP-A-5-99229 (see Fig. 2) discloses a bearing metal for a large engine having a structure described below. An Al-Sn alloy sheet to be a bearing at by.

layer and an Al foil to be an intermediate adhesive layer are stacked, rolled and joined to form a two-layer composite sheet. The composite sheet and steel back metal to be a base material are stacked with the Al foil layer in contact with the steel back metal, arid cladded to form a three-layer composite body (bimetal). Then, the composite body is worked into a semicylindrical shape. And then, a Sn-based alloy layer is provided as a surface layer on a surface of the Al-Sn alloy layer by electroplating. In this case, it is disclosed that a Ni-plating layer is provided between a bearing alloy layer (Al-Sn alloy layer) and a surface layer (Sn-based alloy layer) in order to obtain good bond between the layers.

In the technique described above, it is necessary to provide a Ni-plating layer between the bearing alloy layer (Al-Sn alloy layer) and the surface layer (Sn-based alloy layer) in order to obtain good bond between the layers. However, if the surface layer wears and the Ni-plating layer is exposed, the Ni-plating layer and a counterpart member (for example, a shaft) come into direct contact with each other, which easily causes seizure. In particular, since a product'for a ship is larger than a small product for a general automobile or the like, a large misalignment easily occurs. Thus, the slide portion quickly wears and seizure is easily caused.

* The present invention is achieved in view of the above circumstances, and has an object to provide a slide member with improved fatigue resistance and seizure resistance.

Brief summary of the invention

To achieve the above object, in accordance with a first aspect of the present invention, a slide member includes: a first layer containing, as a main component, first metal having thermal conductivity of 200 to 450 WJ(mK) at from room temperature to 450 K; a second layer containing, as a main component, second metal having lower hardness than the first metal; and a third layer provided between the first layer and the second layer, wherein the third layer contains the first metal as a parent phase (i.e., a matrix) and the second metal as a secondary phase, an area ratio of the secondary phase in the third layer is 10% to 30%, and a thickness of the third layer is 3% or more of a total thickness of the third layer and the first layer.

The slide member in accordance with the first aspect of the present invention has a multilayer structure including the first layer; the third layer, and the second layer. The slide member includes the second layer on a side of a sliding surface, and the first layer on a side opposite to the sliding surface. The first layer is preferably used to be placed on one surface of a base material such as a steel sheet to be back metal. Since the third layer located between the first layer and the second layer contains the first metal that is the main component of the first, layer as the parent phase, the third layer has a high bonding property to the first layer. Since the third layer contains the second metal that is the main component of the layer in contact on the side of the sliding surface as the secondary phase, the third layer is advantageous in light of the bonding property to the layer.

The first metal that is the main component of the first layer and is the parent phase of the third layer has thermal conductivity of 200 to'450 WJ(rnK) at from room temperature to 450 K (about from 20°C to 177°C). If the thermal conductivity of the first metal is 200 WI(mK) or more, heat of the second layer generated by sliding with a counterpart member can be efficiently released via the first metal. Since the layer containing, as a main component, the second metal having lower hardness than the first metal is placed on the sliding surface as the second layer, seizure resistance is improved. Fatigue resistance, seizure resistance, and also mass productivity are required for a slide member. The metal that can be used for the slide member is a metal having thermal conductivity of 450 W/(mK) or less.

The area ratio of the secondary phase (second metal) in the third layer is 10% to 30%. The area ratio of the secondary phase is calculated as described below. A composition image of a section in a thickness direction of a produced slide member is taken by an electron microscope. The obtained image is analyzed using analysis software, and an area of the secondary phase is calculated and represented by percentage.

If the area ratio of the secondary phase is lower than 10%, a sufficient bonding property between the third layer and the layer containing the second metal as a main component cannot be ensured. In this case, minute debonding easily occurs between the secondary phase and the parent phase near an interface of the third layer on a side of the second layer, and a crack easily occurs from the debonding. Thereby, fatigue resistance is reduced. If the area ratio of the secondary phase exceeds 30%, a break occurs in the secondary phase in the third layer which is relatively soft. Thus, a crack is grown easily, thereby fatigue resistance is also reduced.

Thus, the area ratio of the secondary phase in the third layer is preferably 10% to 30%.

Athickness of the third layer is 3% or more of a total thickness of the third layer and the first layer. In order to sufficiently ensure the bonding property between the third layer and the layer containing the second metal as a main component, the thickness of the third layer needs to be 3% or more of the total thickness of the third layer and the first layer.

By adopting the multilayer structure having the first layer, the third layer, and the second layer, the slide member in accordance with the first aspect of the present invention has high fatigue resistance and seizure resistance.

The slide member described above can be produced, for example, as described below. For simplicity of description, Al is used as the first metal as an example. Al satisfies the above condition of the thermal conductivity. Similarly, Sn is used as the second metal. Sn has lower hardness than Al. The first layer mainly contains Al, which is the first metal. The second layer is composed of a Sn-based alloy mainly containing Sn, which is the second metal.

The third layer is composed of an Al-Sn alloy containing Al which is the first metal as the parent phase and Sn which is the second metal as the secondary phase.

First, the Al-Sn alloy is cast into a sheet shape. The obtained Al-Sn alloy sheet is cladded to a base material, for example, made of a steel sheet via an adhesive layer of an Al sheet. Then, so-called bimetal of three layers is obtained. Then, a film of Sn which is the second metal is provided on a surface of the Al-Sn alloy sheet by cold spraying. Then, the Sn-based alloy is provided on the Sn film by casting. The Sn-based alloy layer may be provided by plating.

Fig. 1 is a schematic sectional view of the slide member produced in this manner.

In Fig. 1, a first layer 2 mainly containing Al which is the first metal is provided on a base material 1. Between the first layer 2 and a second layer 3 composed of a Sn-based alloy mainly containing Sn having lower hardness than Al, a third layer 4 is provided. The third layer 4 is composed of an Al-Sn alloy containing Al S which is the first metal as a parent phase and Sn 6 which is the second metal as a secondary phase.

In the above structure, by forming a Sn film on the third layer 4 composed of the Al-Sn alloy by cold spraying, and then by casting the Sn-based alloy on the Sn film, a composite structure of an Al-Sn alloy layer (third layer 4) and a Sn-based alloy layer (second layer 3) is produced.

When the Sn-based alloy layer is provided on the Al-Sn alloy layer, a stable oxide film is generally formed on a surface of the Al-Sn alloy layer. Thus, if the Sn-based alloy is cast as it is, the Sn-based alloy cannot be easily joined to the surface. Thus, in the conventional technique, an oxide film on the surface of the Al-Sn alloy layer needs to be removed by pretreatment before casting. The oxide film is often removed by, for example, a chemical measure using a drug or the like. This causes complexity in process and cost increases. Also, in this case, the surface is to be Ni-plated after the oxide film is removed. However, if the surface is Ni-plated, the Sn-based alloy layer (second layer 3) on the surface side wears and the Ni-plating layer is exposed as is described above. Then, the Ni-plating layer and the counterpart member (for example, shaft) come into direct contact with each other, which causes seizure easily.

Thus, in this development, cold spraying is employed as means for removing the oxide film on the Al-Sn alloy layer (third layer 4). The cold spraying is a technique in which a gas at a lower temperature than a melting point or a softening temperature of material powder is made to be a supersonic flow by a tapered convergent-divergent nozzle, the material powder (in this case, Sn powder) is fed into the flow and accelerated, and is brought into collision with the surface of the base material (in this case, Al-Sn alloy layer (third layer 4)) in a solid phase state at high speed to form a film. An advantage of the cold spraying is that by bringing the material powder into collision with the surface of the base material surface at high speed, the oxide film on the base material surface can be removed, and also a film of the material powder can be formed.

For the above production method, the cold spraying is used to remove the oxide film on the Al-Sn alloy layer (third layer 4) and form the Sn (second metal) film. Thus, the Sn film serves as a bonding aid portion to improve a bonding property between the Al-Sn alloy and the Sn-based alloy having low wettability. Specifically, in the cold spraying, removal of the oxide film and formation of the bonding aid portion can be simultaneously perthrmed, which is cost-efFective. If the bonding aid portion has a thickness smaller than a predetermined thickness, the third layer 4 and the second layer 3 come in contact with each other, since the bonding aid portion is completely melted, for example, at the time of casting of the Sn-based alloy to form the second layer 3. If the bonding aid portion has a thickness larger than the predetermined thickness, a layer comes to be formed between the third layer 4 and the second layer 3, since the bonding aid portion is not completely melted.

The Sn-based alloy layer to be the second layer 3 may be formed by plating.

In accordance with a second aspect of the invention, the slide member in accordance with the first aspect of the present invention fUrther includes a fourth layer between the second layer and the third layer, wherein the fourth layer includes a fifth layer in contact with the third layer and a sixth layer in contact with the second layer, the fifth layer containing the second metal as a main component and being softer than the second layer, and the sixth layer being composed of a group of minute intermetallic compound particles containing the first metal.

By providing the fourth layer between the second layer and the third layer, fatigue resistance is further improved. One reason is that since the fifth layer softer than the second layer is present between the second layer and the third layer, the fifth layer serves as a cushion when a load is applied from the surface of the slide member. This reduces burden on the second layer and improves fatigue resistance. The sixth layer is composed of the group of minute intermetallic compound particles distributed in a strip shape. The minute intermetallic compound particles are harder than the parent phase. The presence of the minute intermetallic compound particles causes dispersion strengthening to prevent excessive deformation of the fifth layer and improves fatigue resistance. Further, when a crack occurs in the second layer, growth of the crack can be prevented by the sixth layer. Thus, large damage is prevented.

Fig. 2 schematically shows a structure having a fourth layer 7 between the second layer 3 and the third layer 4. The fourth layer 7 includes a fifth layer 8 and a sixth layer 9.

The sixth layer 9 is composed of a group of minute intermetallic compound particles tO and is distributed in a strip shape.

The slide member in accordance with the second aspect of the present invention can be produced, for example, as described below. For simplicity of description, it is assumed that the second layer contains Cu as an accessory component as an example. Similarly, the minute intermetallic compound particles in the sixth layer contain Cu as a main component.

In production of the slide member in accordance with the second aspect of the present invention, hot dipping with Sn is conducted on an Al-Sn alloy which forms the third layer before forming the second layer (Sn-based alloy layer), and a Sn-based alloy containing Cu is cast thereon. Specifically, bimetal containing the Al-Sn alloy is immersed in a hot Sn bath.

An oxide film or impurity on an Al-Sn alloy surface is then removed in the Sn bath by physical means such as barrel polishing. And then, the Al-Sn alloy surface is hot dipped with Sn. This method can easily form a thicker bonding aid portion, that is, a Sn film than that formed by cold spraying. Then, by casting the Sn-based alloy on the Sn film at proper temperature and for proper time, a multilayer structure as shown in Fig. 2 is obtained. In this case, for example, the fifth layer 8 is composed of Sn, and the minute intermetallic compound particle 10 in the sixth layer 9 is composed of a Cu-Al alloy containing Cu as a main component and also containing Al.

According to such a production method, the structure of the slide member in accordance with the second aspect of the present invention can be obtained, and also a high io bonding property can be advantageously obtained. Since the oxide film or impurity on the Al-Sn alloy surface is removed in the Sn bath, the Al-Sn alloy and Sn can bond to each other immediately after formation of a new surface of the Al-Sn alloy surface. Tbereby,.the possibility that the oxide film or impurity is got caught in, and a bonding property is improved.

Since atoms are sufficiently diffused in a bonding interface at the time of casting of the Sn-based alloy, a stronger bonding force is provided. Since a high bonding property can prevent generation of a crack in the interface, high fatigue resistance is provided. Further, since a thick Sn film can be easily formed, the method is particularly suitable for forming the fourth layer between the third layer and the second layer.

The Sn-based alloy layer to be the second layer 3 may be formed by plating.

In accordance with a third aspect of the present invention, the second layer is composed of metal structure in which intermetallic compound particles are dispersed in a matrix composed of a main component, and an average particle angle of the intermetallic compound particles is 55° or less.

in Fig. 2, intermetallic compound particles II of, for example, Sn and Cu are dispersed in the second layer 3. A particle angle of the intermetallic compound particle 11 is measured as described below. Metal structure in a section in a thickness direction of the produced slide member is taken by an optical microscope. The obtained image is analyzed using analysis software to measure the particle angle of the intermetallic compound particle ii.

For the particle angle, a horizontal line perpendicular to the thickness direction (depth direction) of the third Layer is set to 00. As shown in Fig. 3, the intermetallic compound particles 11 are enclosed in a rectangle, and a particle angle 0 is measured from tanO b/a. An average of obtained particle angles B is an average particle angle. If the average particle angle is 55° or less, fatigue failure hardly occurs from the intennetallic compound particles Il. Thus, the average particle angle of the intermetallic compound particles in the second layer is preferably 550 or less. By forming the second layer by casting, the average particle angle can be reliably controlled to 550 or less.

In accordance with a forth aspect of the present invention, a thickness of the second layer is 3% to 45% of a total thickness from the first layer to the second layer including the third layer and also the fourth layer in some cases. In view of a presence ratio of the first layer and the third layer having higher fatigue resistance than the second layer, the thickness of the second layer is preferably 45% or less of the total thickness. In view of the possibility of exposure of the Al-Sn alloy of the third layer by wear of the second layer, the thickness of the second layer is preferably 3% or more of the total.thickness.

In accordance with a fifth aspect of the present invention, an average thickness of the fifth layer is 0.2% to 5% of the total thickness of the first layer and the third layer. An interface of the fifth layer ona side of the sixth layer has a corrugated shape. An average height of protrusions in the corrugated shape is 2 to 15 sm, and an average distance between adjacent protrusions is 20 to 100.tm.

The interface between the fifth layer and the sixth layer has the corrugated shape (has irregularities in the thickness direction). Since this can efficiently provide a cushioning effect for a load from a shearing direction (direction perpendicular to the thickness direction), fatigue resistance is improved. If the thickness of the fifth layer is 0.2% or more ofthetotal thickness of the first layer and the third layer, the cushioning effect of the fifth layer can be reliably provided. If the thickness of the fifth layer is 5% or less of the total thickness of the first layer and the third layer, the soft fifth layer has an appropriate thickness to provide high fatigue resistance. Thus, the thickness of the fifth layer is preferably 0.2% to 5% of the total thickness of the first layer and the third layer.

The average height of the protrusions in the corrugated shape of the interface of the fifth layer on the side of the sixth layer, and the average distance between adjacent protrusions are measured as described below. A metal structure image of a section in the thickness direction of a produced slide member is taken by an electron microscope. The obtained image is analyzed using analysis software to measure the average height of the protrusions in the corrugated shape and the average distance between adjacent protrusions.

The height of the protrusion in the corrugated shape is a height from a bottom to a top of the protrusion. In this application, the average height of the protrusions in the corrugated shape being 2 to 15 p.m means that an average value of heights of the protrusions in each of three measurement views is within 2 to 15 km Specifically, for example, in the case where there are two protrusions in a first measurement view and an average height of the two protrusions is 3 p.m, there being three protrusions in a different second measurement view and an average height of the three protrusions being 6 sm, and there being four protrusions in a different third measurement view and an average height of the four protrusions being 13 urn, it follows that the average height of the protrusions is within 2 to 15 t.tm.

The distance between adjacent protrusions is a distance between tops of two adjacent protrusions. The average distance between adjacent protrusions being 20 to 100 jsm means that an average value of distances between adjacent protrusions in each of three measurement views is within 20 to 100 pm, similar to the measurement of the average height.

If the average height of the protrusions in the corrugated shape is 2 pm or more, a high cushioning effect for a load from the shearing direction can be provided. If the average height of the protrusions exceeds 15 Mm, fatigue resistance tends to be reduced. Thus, the average height of the protrusions in the corrugated shape of the interface between the fifth layer and the sixth layer is preferably within 2 to 15 pm.

If the average distance between adjacent protrusions is less than 20 pm, a small is distance between protrusions on which stress is concentrated tends to cause a break. If the average distance exceeds 100 Mm, the cushioning effect for a load from the shearing direction tends to be reduced. Thus, the average distance between adjacent protrusions is preferably within 20 to 100 pm.

The height and the distance of the protrusions can be controlled by adjusting a casting condition in formation of the second layer and by adjusting a heat treatment condition.

In accordance with a sixth aspect of the present invention, in the sixth layer, the minute intermetallic compound particles having an average particle size of 5 pm or less are distributed in a strip shape along the interface shape of the fifth layer, and 70% or more of the minute intermetallic compound particles are present in a 10 pm width in a thickness direction from the fifth layer toward the second layer If the average particle size of the minute intermetallic compound particle in the sixth layer exceeds 5 pm, the probability of coupling between the minute intermetallic compound particles tends to increase, and the cushioning effect of the fifth layer tends to be reduced. If 70% or more of the intermetallic compound particles are present in the 10 pm width in the thickness direction from the fifth layer toward the second layer, the effect of the sixth layer is effectively provided.

In accordance with a seventh aspect of the present invention, the first metal is Al or Cu. The second metal is Sn or Pb. And the second layer contains Cu as an accessory component.

As for the first metal, Al having high fatigue resistance is particularly preferable.

In view of cost, Al is more preferable than Cu. As for the second metal, Sn having high seizure resistance is particularly preferable. In view of an environmental problem, Sn is more preferably used than Pb. The second layer containing Cu as an accessory component can increase strength of the second layer. The second layer may contain Cu and also Sb. The second layer containing Sb can increase strength of the second layer without reducing a cushioning property of the fifth layer.

[n accordance with an eighth aspect of the present invention, the minute intérmetallic compound particle in the sixth layer contains Cu as a main component in the slide member in accordance with the seventh aspect of the present invention. Thus, in this case, the minute intermetallic compound particle containing the first metal contains Cu as a main component. The minute intermetallic compound particle is preferably a Cu-Al based particle.

By making the second layer contain Cu, the sixth layer is efficiently formed: Thereby, the effect of the sixth layer is effectively provided.

Brief description of the several views of the drawings Fig. 1 is a schematic sectional view of a slide member according to a first embodiment of the present invention; Fig. 2 is a schematic sectional view of a slide member according to a second embodiment of the present invention; Fig. 3 illustrates a particle angle; and Fig. 4 illustrates a height of a protrusion in a corrugated shape, and a distance between adjacent protrusions

DetaileddescriPtion of the invention

To confirm an advantage of a slide member of the present invention, samples (embodiment products 1 to 34 and comparative products 1 to 5) shown in Tables I and 2 were produced. Seizure tests of these samples were performed under test conditions shown in Table 3. And also, fatigue tests of the samples were performed under test conditions shown in Table 4. Test results are shown in Table 2: -10-V t-' -?: C , U z cc NNNm i ri e -: -4,-d d 0 I. *--c'3⁄4 -<! "t C 0 0 0 00 0 0* " Ce! n. -0 -0 . 2 i i q rnc en m 0 0.q c'4 ci 0* 0 r oo'oO O \O O D C L$ i.4 ¶4 0 0 0 0 0 zzzmn : mNOZm C." -Cl) C) E2 L3flQOM jAllUOWAE -11 - T j'Yr 1 fT 1;fl G A I;Q th ° ; th I oocJo QQQJQQQQOQOLQOOOO i C-) L1 C-) C) C) C) 0 -1 I;s I ° C) C) ___ --t-----------__-- 1 I I *

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[Table 3]

TEST CONDITION -.

SEIZURE TEST

TESTING MACHINE SEIZURE TESTING MACHINE

NUMBER OF REVOLUTIONS -7200 rpm TEST LOAD INCREASE BY 2.5 MPa EVERY 10 MINUTES LUBRICATION TEMPERATURE 90°C LUBRICATION AMOUNT 200 mI/mm LUBRICANT VG22 MATERIALOF SHAFT S55C

SPECIFIC LOAD WHEN BEARING BACK

hAT TTAI' W TEMPERATURE EXCEEDS 200°C OR WHEN SHAFT E vnL,IJflLIJn DRIVING BELT SLIPS BY TORQUE CHANGE IS

REGARDED AS SEIZURE LOAD

[Table 41

TEST CONDITION

-FATIGUE TEST

TESTING MACHINE H FATIGUE TESTING MACHINE

NUMBER OF REVOLUTIONS -3300 rpm LUBRICATION TEMPERATURE 110°C LUBRICATION AMOUNT tOO mi/mm LUBRICANT -VG68 * MATERIAL OF SHAFT SS5C * EVALUATION METHOD MAXIMUM SPECIFIC LOAD WITHOUT FATIGUE As for a structure of the embodiment product, there are two main structures of a structure without afourth layer shown in Fig. I and a structure with the fourth layer (fifth layer and sixth layer) shown in Fig. 2.

* A production method of a slide member of a first embodiment without a fourth layer (embodiment products I to 4, 9 to 12, 33, and 34) will be described below.

First, a method for producing the embodiment products 9 to 12 will be described.

-15 -An Al-Sn alloy to be a third layer was first cast into a sheet shape. I he obtained Al-Sn alloy sheet was roll bonded on a base material made of a steel sheet via an Al sheet to be a first layer.

Thereby, so-called bimetal of 3 layers was produced. At this time, the bimetal may be produced by explosive bonding instead of roll bonding. Sn powder having an average particle size of 15 j.tm was brought into collision with the Al-Sn alloy sheet in the produced bimetal at gas pressure of 1.5 MPa by cold spraying to form a Sn film. Then, a Sn-based alloy at 500°C was cast on the Sn film. Compositions of the layers are shown in Table 1. A multilayer structure produced as above was worked into a semicircular shape to be a half bearing and used as a sample.

A method for producing the embodiment products I to 4 is different from the method for producing the embodiment product 9 to 12 in that a Sn-based alloy to be a second layer is provided by electroplating instead of casting.

The embodiment product 33 included a first layer of Cu, a second layer of a Bi-based alloy containing mainly Bi having lower hardness than Cu, and a third layer of a Cu-Bi 16 alloy containing Cu as a parent phase and Bi as a secondary phase. The method for producing the embodiment product 33 was the same as the method for producing the embodiment products I to 4. The Bi-based alloy of the second layer was provided by electroplating.

The embodiment product 34 included a first layer of Cu, a second layer of a Pb-based alloy containing mainly Pb having lower hardness than Cu, and a third layer of a Cu-Pb alloy containing Cu as a parent phase and Pb as a secondary phase. The method for producing the embodiment product 34 was the same as the method for producing the embodiment products 9 to 12. The Pb-based alloy of the second layer was provided by casting.

A method for producing a slide member of a second embodiment (embodiment products 5 to 8 and 13 to 32) with a fourth layer will be described below.

As for the embodiment products 13 to 32, similar to the embodiment products 9 to 12 described above, an Al-Sn alloy to be a third layer was first cast into a sheet shape. The obtained Al-Sn alloy sheet was roll bonded on a base material made of a steel sheet via an Al sheet to be a first layer. Thereby, bimetal of 3 layers is produced. At this time, the bimetal may be produced by explosive bonding instead of roll bonding. The produced bimetal was immersed in a hot Sn bath at 300°C containing multiple iron balls having a diameter of 5 mm.

Then, a container of the Sn bath was rotated at 100 rpm to remove an oxide film or impurity on an Al-Sn alloy surface. Thereby, the Al-Sn alloy surface was hot dipped with Sn. Then, a Sn-based alloy at 500°C was cast on the hot-dipped Sn plating. Compositions of the layers are shown in Table 1. A multilayer structure produced as above was worked into a semicircular shape to be a half bearing and used as a sample.

A method for producing the embodiment products 5 to S is different from the method for producing the embodiment product 13 to 32 in that a Sn-based alloy to be a second layer is provided by electroplating instead of casting.

The comparative products 1 to 5 were basically produced by the same method as the method for producing the embodiment products 1 to 4.

In Table 1, hardness of the second layer was measured with test load ofHVO.0l, and hardness of the fifth layer was measured with test load of HVO.000l, respectively, by using a micro-Vickers hardness testing machine.

In Table 2, a thickness (%) of the third layer represents a percentage of a thickness of the third layer with respect to a total thickness of the third layer and the first layer. A thickness of each layer was calculated by taking a composition image of a section in a thickness direction using an electron microscope, and by analyzing the obtained image using analysis software (image-Pro Plus (version 4.5) produced by Planetron, Inc.). As for a secondary phase area ratio (%) in the third layer, similar to the above, a composition image of a section in the thickness direction of a produced slide member was taken by an electron microscope, the obtained image being analyzed using the analysis software, and an area of the secondary phase being calculated and represented by percentage: An average particle angle of the intermetallic compound particle in the second layer is measured as described below. Similar to the above, a metal structure in a section in the thickness direction of the produced slide member was taken by an optical microscope. The obtained image was analyzed using analysis software to measure a particle angle B shown in Fig. 3. An average of obtained particle angles 0 is an average particle angle. A thickness (%) of the second layer represents a percentage of a thickness of the second layer with respect to a total thickness from the first layer to the second layer including the third layer and also the fourth layer in some cases.

An average thickness (%) of the fifth layer represents a percentage of an average thickness of the fifth layer with respect to the total thickness of the first layer and the third layer.

An average height of protrusions is a height of a protrusion in a corrugated shape of an interface of the fifth layer, that is, an average of distances H (see Fig. 4) between an intersection point of a tangential line connecting adjacent bottoms of protrusions 12 and a line from a top in a thickness direction T, and the top. An average distance between protrusions is a distance between adjacent protrusions in the corrugated shape of the interface of the fifth layer, that is, an average of distances L (see Fig. 4) perpendicular to the thickness direction T of tops of the adjacent protrusions 12. The average height of the protrusions and the averaged distance between the protrusions were also calculated by taking a composition image of a section in the thickness direction of a produced slide member using an electron microscope, and by analyzing.the obtained image using analysis software.

The average particle size of the minute intermetallic compound particles in the sixth layer was also calculated by taking a composition image of a section in the thickness direction of the produced slide member using an electron microscope, and by analyzing the obtained image using analysis software. Distribution (%) of the minute intermetallic compound particles in the sixth layer is expressed as a percent of a total area ratio of minute intermetallic compound particles existing in a 10 tm width in the thickness direction from the fifth layer toward the second layer, to all the minute intermetallic compound particles in the sixth layer.

The distribution (%) of the minute intermetallic compound particles in the sixth layer was also calculated by taking a composition image of a section in the thickness direction of the produced slide member using an electron microscope, and by analyzing the obtained image using analysis software.

Next, the test results will be considered mainly with reference to Table 2.

First, the embodiment products I to 4 are compared with the comparative products 1 to 5. In the comparative products 1 to 3, a thickness of a third layer was less than 3% of a total thickness of the third layer and a first layer. in the comparative products 1 and 4, an area ratio of a secondary phase was less than 10%. In the comparative products 2 and 5, an area ratio of a secondary phase exceeded 30%. In contrast to this, as for the embodiment products Ito 4, the thickness of the third layer was 3% or more of the total thickness of the third layer and the first layer, and the area ratio of the secondary phase was 10% to 30%. Thus, it can be found that the embodiment products l'to 4 have higher seizure resistance and fatigue resistance than the comparative products 1 to 5.

The embodiment products 1 to 4 are compared with the embodiment products 9 to 12. in the embodiment products I to 4, the Sn-based alloy layer to be the second layer was provided by electroplating. In contrast to this, in the embodiment products 9 to 12, the Sn-based alloy layer to be the second layer was provided by casting. In the embodiment product 9 to 12, since the Sn-based alloy layer to be the second layer was provided by casting, the average particle angle of the intermetallic compound particles in the second layer was controlled to 550 or less. Thus, it can be found that the embodiment products 9 to 12 have higher seizure resistance than the embodiment products 1 to 4. In the embodiment product 3, the intermetallic compound particles were not deposited in the second layer.

The embodiment products I to 4 are compared with the embodiment products 5 to 8. The embodiment products 5 to 8 include a fourth layer. * Thus, it can be found that the embodiment products 5 to 8 have higher fatigue resistance than the embodiment product 1 to 4 without a fourth layer.

The embodiment products 5 to S are compared with the embodiment products 13 to 16. In the embodiment products 13 to 16, since the Sn-based alloy layer to be the second layer was provided by casting, the average particle angle of the intermetallic compound particles in the second layer was controlled to 55° or less. Thus, it can be found that the embodiment product 13 to 16 have higher seizure resistance and fatigue resistance than the embodiment products5toS.

The embodiment products 13 to 16 are compared with the embodiment products I? to 19. In the embodiment products 17 to 19, the thickness of the second layer was controlled within 3% to 45% of a total thickness from the first layer to the second layer Thus, it can be found that the embodiment products 17 to 19 have higher fatigue resistance than the embodiment products 13 to 16.

The embodiment product 18 is compared with the embodiment products 20 to 22.

In the embodiment products 20 to 22, the thickness of the fifth layer was controlled within 0.2% to 5% of the total thickness of the first layer and the third layer. Thus, it can be found that the embodiment products 20 to 22 have higher fatigue resistance than the embodiment product 18.

The embodiment product 21 is compared with the embodiment products 23 to 25.

In the embodiment products 23 to 25, the average height of the protrusions in the corrugated shape of the interface of the fifth layer was controlled within 2w 15 zm. Thus, it can be found that the embodiment products 23 to 25 have higher fatigue resistance than the embodiment product 21.

The embodiment product 24 is compared with the embodiment products 26 to 28.

In the embodiment products 26 to 28, the average distance between the protrusions in the corrugated shape of the interface of the fifth layer was controlled within 20 to 100 m. Thus, it can be found that the embodiment product 26 to 28 have higher fatigue resistance than the embodiment product 24.

The embodiment product 27 is compared with the embodiment products 29 and 30. In the embodiment products 29 and 30, the average particle size of the minute intermetallic compound particles in the sixth layer was controlled to 5 m or less. Thus, it can be found that the embodiment products 29 and 30 have higher fatigue resistance than the embodiment product 27.

The embodiment product 30 is compared with the embodiment products 31 and 32. in the embodiment products 31 and 32, a distribution state of the minute intermetallic.

compound particles in the sixth layer was 70% or more. Thus, it can be found that the embodiment product 31 and 32 have higher fatigue resistance than the embodiment product 30.

S The embodiment product 33 is compared with the embodiment product 1. Ih the embodiment product 33, first metal was Cu, second metal being Bi, a third layer being an Cu-Bi alloy, and a second layer being a Bi-based alloy plating, and the layers containing different components from those in the embodiment product 1. However, the same seizure resistance and fatigue resistance as in the embodiment product 1 can be obtained.

to The embodiment product 34 is compared with the embodiment product 9. In the embodiment product 34, first metal was Cu, second metal being Pb, a third layer being a Cu-Pb alloy, and a second layer being a Pb alloy casting, and the layers containing different components from those in the embodiment product 9. However, the same seizure resistance and fatigue resistance as in the embodiment product 9 can be obtained.

in a slide member that particularly requires seizure resistance, Ag can be used as first metal and Sn can be used as second metal.

In this embodiment, while the example of using Al as the first layer is described, an Al-Sn alloy may be used. Specifically, the first layer may contain first metal as a main component, and may have the first metal as a parent phase and the second metal.as a secondary phase. In this case, an area ratio of the secondary phase in the first layer is preferably lower than that in the third layer in terms of strength of the slide member. As for an accessory component of the first layer, an element different from the second metal in the third layer may be used.

This embodiment can be changed without departing from the scope of the invention.

A description about incidental impurity is omitted. Each composition may contain incidental impurity.

Elements other than those described above, for example, Si, Mn, Zr, Fe, or additives such as hard particles or a solid lubricant may be added to each layer to the extent not preventing the advantage of the invention.

Claims

CLAIMS: 1. A slide member, comprising: a first layer (2) mainly containing a first metal having thermal conductivity of 200 to 450 W/(mK) at from room temperature to 450 K; a second layer (3) mainly containing a second metal having tower hardness than the first metal; and a third layer (4) provided between the first layer (2) and the second layer (3), wherein the third layer (4) contains the first metal (5) as a parent phase and the second metal (6) as a secondary phase, an area ratio of the secondary phase in the third layer (4) being 10% to 30%, and a thickness of the third layer (4) being 3% or more of a total thickness of the third layer (4) and the first layer (2).
2. The slide member according to claim 1, further comprising a fourth layer (7) between the second layer and the third layer, wherein the fourth layer (7) includes a fifth layer (8) in contact with the third layer and a sixth layer (9) in contact with the second layer, the fifth layer containing the second metal as a main component and being softer than the second layer, and the sixth layer being composed of a group of minute intermetallic compound particles containing the first metal.
3. The slide member according to claim I or 2, wherein the second layer is composed of metal structure in which intermetallic compound particles are dispersed in a matrix of a main component, and an average particle angle of the intermetallic compound particles being 55° or less.
4. The slide member according to any one of claims ito 3, wherein a thickness of the second layer is 3% to 45% of a total thickness from the first layer to the second layer
5. The slide member according to claim 2, wherein an average thickness of the fifth layer is 0.2% to 5% of the total thickness of the first layer and the third layer, an interface shape of the fifth layer on a side of the sixth layer having a corrugated shape, and an average height of protrusions in the corrugated shape being 2 to 15 iim, and an average distance between adjacent protrusions being 20 to 100 pm.
6. The slide member according to claim 2 or 5, wherein in the sixth layer, the minute intermetallic compound particles having an average particle size of 5.tni or less are distributed in a strip shape along the interface shape of the fifth layer, and 70% or more of the minute intermetallic compound particles being present in a 10 sm width in a thickness direction from the fifth layer toward the second layer
7. The slide member according to any one of claims Ito 6, wherein the first metal is Al or Cu, the second metal being Sn or Pb, and the second layer containing Cu as an accessory component.
8. The slide member according to any one of claims 2 to 6, wherein the first metal is Al or Cu,the second metal being Sn or Pb, the second layer containing Cu as an accessory component, and the minute intermetallic compound particle in the sixth layer containing Cu as a * main component.
9. A slide member substantially as hereinbefore described with reference to figure 1 or figure 2 of the drawings.