Sliding member

Abstract

To provide a slide member capable of reducing man-hours for removing Bi and improving the adhesive force between a lining layer and a coating layer.SOLUTION: A slide member 10 of an embodiment comprises a lining layer 11 including a Bi phase 17, and a coating layer 12 containing Ni, provided on the surface of the lining layer 11, and forming a penetration unit 19 where a part has penetrated into the lining layer 11 side in an interface 16 with the lining layer 11. In an arbitrary observation region 20 including the interface 16 between the lining layer 11 and the coating layer 12, R=S1 / S2 which is a value R of the ratio between the maximum area S1 of the Bi phase 17 included in the lining layer 11 and the maximum area S2 of the penetration part 19 which has penetrated into the lining layer 11 is 1.00≤R≤9.00.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This embodiment relates to a sliding member.

Background Art

[0002] Conventionally, a sliding member having an overlay layer provided on the surface of a Cu-based lining layer has been known (Patent Document 1). In Patent Document 1, by removing the second-phase component contained in the lining layer from the surface of the lining layer, the bonding strength between the lining layer and the overlay layer is improved. Further, in order to stabilize the overlay layer, it is also disclosed that a Ni coating layer is provided on the surface of the lining layer. However, Bi, which is the second-phase component contained in the lining layer, forms a Bi-Ni compound at the interface with the coating layer depending on the temperature conditions during operation of the applied device. This Bi-Ni compound causes a decrease in the adhesive force between the lining layer and the coating layer. Therefore, when adopting the configuration as in Patent Document 1, it is necessary to thoroughly remove the Bi phase existing on the surface of the lining layer, that is, the surface in contact with the coating layer. The removal of this Bi phase requires a long time of cleaning, such as cleaning using an acid and ultrasonic cleaning with ultrasonic irradiation, and there is a problem that a large number of man-hours are required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, an object of the present invention is to provide a sliding member that improves the adhesive force between the lining layer and the coating layer while reducing the man-hours for removing Bi.

Means for Solving the Problems

[0005] To solve the above problems, the sliding member of the present embodiment includes a lining layer containing a Bi phase, and a coating layer containing Ni, provided on the surface of the lining layer, and forming an intrusion portion that partially penetrates into the lining layer side at the interface with the lining layer. In any observation region including the interface between the lining layer and the coating layer, the ratio value R = S1 / S2 of the maximum area S1 of the Bi phase contained in the lining layer to the maximum area S2 of the intrusion portion that has penetrated into the lining layer is 1.00 ≦ R ≦ 9.00.

[0006] The sliding member of the present embodiment sets the ratio value R of the maximum area S1 of the Bi phase to the maximum area S2 of the intrusion portion. When the Bi phase is removed by cleaning or the like, a concave portion corresponding to the removed Bi phase is formed in the lining layer. Therefore, the concave portion corresponding to the removed Bi phase is replaced by Ni or Ni alloy forming the coating layer. Thereby, the generation of Bi-Ni compounds is reduced. Further, even if a part of the Bi phase remains in the lining layer, Ni or Ni alloy penetrates into the concave portion formed by the removal of the Bi phase as an intrusion portion. Therefore, the intrusion portion that has penetrated into the concave portion is in a state of biting into the lining layer. As a result, the coating layer is in a state of being hooked on the lining layer in a predetermined shape, and even if a Bi-Ni compound is formed, the peeling from the lining layer is reduced. Thus, even if the cleaning of the Bi phase contained in the lining layer is insufficient, the bonding force between the lining layer and the coating layer is ensured. Therefore, it is possible to improve the adhesive force between the lining layer and the coating layer while reducing the man-hour for removing Bi.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Mode for Carrying Out the Invention

[0008] Hereinafter, a sliding member according to an embodiment will be described with reference to the drawings. As shown in FIG. 1, the sliding member 10 includes a lining layer 11 and a coating layer 12. The sliding member 10 is formed, for example, in a cylindrical shape or a semi-divided shape and is used for a bearing device or the like. The lining layer 11 is provided on one end face of the backing layer 13. Further, the sliding member 10 includes an overlay layer 14 on the side opposite to the backing layer 13 of the coating layer 12. That is, the coating layer 12 is an intermediate layer provided between the lining layer 11 and the overlay layer 14. The surface of the overlay layer 14 forms a sliding surface 15 that slides against a mating member (not shown). Note that the sliding member 10 is not limited to a semi-divided shape of a split cylindrical shape, and may be divided into three or more parts in the circumferential direction.

[0009] The lining layer 11 is formed of a Cu-based alloy. The lining layer 11 has Cu as a main component and contains Bi. The lining layer 11 contains 0.1 to 2.0 mass% of Bi. Bi contributes to the improvement of workability, for example, during mechanical processing such as cutting or polishing of the formed lining layer 11. The lining layer 11 is not limited to a Cu-based alloy, and may be a Sn-based alloy or an Al-based alloy. The thickness of the overlay layer is preferably set to 10 μm to 30 μm. In the case of the lining layer 11, it is preferably set to 0.1 mm to 1.5 mm. In this case, the thickness of the coating layer 12 is preferably set to 1 μm to 5 μm.

[0010] The coating layer 12 is formed of Ni. The coating layer 12 may be a Ni alloy. In this case, the coating layer 12 may contain Cr or the like at 30 mass% or less in Ni. The coating layer 12 is formed, for example, by plating or the like on the surface opposite to the backing layer 13 of the lining layer 11. The boundary between the lining layer 11 and the coating layer 12 is the interface 16. The backing layer 13 is formed of an alloy mainly composed of Fe, such as steel or the like. One or more layers such as an intermediate layer (not shown) may be provided between the lining layer 11 and the backing layer 13. The overlay layer 14 is formed of, for example, Sn or an alloy mainly composed of Sn. Note that the overlay layer 14 may be other elements or alloys instead of Sn or Sn-based alloys.

[0011] The lining layer 11 contains a Bi phase 17 derived from Bi added to the Cu-based alloy as shown in FIG. 2 in its structure. Although the Bi phase 17 is contained in the structure of the Cu-based alloy, there are also those that are exposed at the interface 16. After the lining layer 11 is formed on the surface of the backing layer 13, it is washed, for example, with acid or water. As a result, most of the Bi phase 17 exposed at the interface 16 among the Bi phases 17 contained in the lining layer 11 is removed by washing. The interface 16 between the lining layer 11 and the coating layer 12 is preferably formed to be generally flat. However, this interface 16 is not limited to being flat. When the Bi phase 17 is removed at the interface 16 of the lining layer 11, the portion where the Bi phase 17 is removed forms a recess 18 that is recessed toward the lining layer 11 side. When a coating layer 12 of Ni or a Ni alloy is formed on the interface 16 including this recess 18, for example, by plating or the like, a part of the Ni or Ni alloy constituting the coating layer 12 penetrates into the recess 18 of the lining layer 11. That is, the recess 18 formed by the removal of the Bi phase 17 at the interface 16 is filled with the Ni or Ni alloy forming the coating layer 12. As a result, the coating layer 12 forms an intrusion portion 19 that partially intrudes toward the lining layer 11 side at the interface 16 with the lining layer 11. This intrusion portion 19 bites into the inside of the lining layer 11 on the backing layer 13 side rather than the interface 16 between the lining layer 11 and the coating layer 12.

[0012] In this embodiment, in any observation region 20 shown in FIGS. 1 and 2, the maximum area S1 of the Bi phase 17 included in the lining layer 11 and the maximum area S2 of the intrusion part 19 that has intruded into the lining layer 11 are measured. The ratio value R is calculated as R = S1 / S2 using the measured maximum area S1 and maximum area S2. In the case of this embodiment, the observation region 20 is set as an arbitrary range including the intrusion part 19 in a cross section including the interface 16 between the lining layer 11 and the coating layer 12. The dimensions of the observation region 20 are set, for example, in the range of 450 μm in the thickness direction × 600 μm in width. Note that the dimensions of this observation region 20 are exemplary, and can be set to arbitrary dimensions within the range where the intrusion part 19 can be observed.

[0013] The maximum area S1 of the Bi phase 17 included in the lining layer 11 is the area of the Bi phase with the largest area among the Bi phases 17 included in this observation region 20. The area of the Bi phase 17 correlates with the area of the particles that would have been present at the interface and the area of the particles included inside the lining layer 11. Here, the maximum area S1 of the Bi phase 17 is measured based on the particles of the Bi phase 17 included inside the lining layer 11. For example, as shown in FIG. 2, when a plurality of particles of the Bi phase 17 are included in the observation region 20, the area of the Bi phase 17 with the largest area is the maximum area S1. The observation region 20 is a cross section cut in the thickness direction, such as the direction along the axis of the sliding member 10 or the direction perpendicular to the axis, and can be set in any orientation as long as the intrusion part 19 can be observed. Also, in this case, the observation region 20 has a larger length in the width direction perpendicular to the thickness direction of the lining layer 11 compared to the length in the thickness direction of the lining layer 11, such as 450 μm in the thickness direction × 600 μm in width as described above.

[0014] As shown in Fig. 3, the intrusion part 19 is defined as the area on the lining layer 11 side with respect to a virtual straight line L connecting the vertices 21 and 22 on the interface 16 side of the intrusion part 19. That is, the intrusion part 19 is the area shaded in Fig. 3. And the area of the region on the lining layer 11 side with respect to this straight line L is the area of the intrusion part 19. When a plurality of intrusion parts 19 are observed in the observation region 20 as shown in Fig. 2, the area of the intrusion part 19 with the largest area among these intrusion parts 19 is the maximum area S2. From the maximum area S1 and the maximum area S2 obtained in this way, the ratio value R is calculated. In this embodiment, the ratio value R satisfies 1.00 ≦ R ≦ 9.00.

[0015] The Bi phase 17 included in the lining layer 11 preferably has a maximum area S1 such that S1 ≦ 810 μm 2 If the maximum area of the Bi phase 17 is set in this way, the adhesion between the lining layer and the coating layer can be further improved. Also, the Bi phase 17 is essential for improving workability during processing such as cutting of the lining layer 11. Therefore, from the viewpoint of ensuring the workability of the lining layer 11, the maximum area S1 of the Bi phase 17 is preferably 20 μm 2 ≦ S1. The maximum area S1 of the Bi phase 17 included in the lining layer 11 preferably satisfies S1 ≦ 810 μm 2 The maximum area S2 of the intrusion part 19 is preferably 20 μm 2 ≦ S2 ≦ 90 μm 2 By setting the maximum area S1 of the Bi phase 17 in this way, it is possible to achieve both an improvement in workability during processing such as cutting of the lining layer 11 and an improvement in the adhesion to the coating layer 12.

[0016] When forming the coating layer 12 containing Ni on the surface of the lining layer 11, if the Bi17 added to the lining layer 11 is exposed to the coating layer 12, Bi of the Bi phase 17 diffuses into the coating layer 12. For example, when the temperature of the sliding member 10 is between 100°C and 250°C, Bi in the Bi phase 17 contained in the lining layer 11 that contacts the coating layer 12 at the interface 16 diffuses toward the coating layer 12 side. Therefore, near the interface 16, a Bi-Ni compound is likely to be formed from Bi derived from the lining layer 11 and Ni derived from the coating layer 12. This Bi-Ni compound reduces the adhesive force between the lining layer 11 and the coating layer 12. Therefore, in the conventional case, the interface 16 of the lining layer 11 requires a large amount of labor and thorough advanced cleaning to avoid the residue of the Bi phase 17 and remove almost all of the Bi phase.

[0017] On the other hand, in the present embodiment, although the interface 16 of the lining layer 11 is cleaned, advanced cleaning as in the conventional case is not required. In the case of the present embodiment, most of the Bi phase 17 exposed at the interface 16 is removed by, for example, simple cleaning with an acid. Then, the lining layer 11 forms a recess 18 at the interface 16 when the Bi phase 17 is removed. The coating layer 12 laminated on the lining layer 11 enters the recess 18 formed in the lining layer 11 to form an intrusion part 19. As a result, the formed coating layer 12 is in a state where the intrusion part 19 intrudes into the lining layer 11 and meshes with it. In the present embodiment, the ratio value R is set to 1.00 ≦ R ≦ 9.00. Thus, even when the Bi phase 17 that could not be removed remains in the recess 18, the intrusion part 19 that has intruded into the lining layer 11 meshes sufficiently with the lining layer 11, and the strength, that is, the adhesive force, at the interface 16 between the lining layer 11 and the coating layer 12 is improved. Therefore, it is possible to improve the adhesive force between the lining layer 11 and the coating layer 12 while reducing the man-hours for removing the Bi phase 17.

[0018] Next, the manufacturing method of the sliding member 10 of the present embodiment will be described. The lining layer 11 has fine Bi phases 17 dispersed in a Cu-based alloy. Such a lining layer 11 is formed, for example, by using sintering. Sintering is carried out by mixing a bronze powder that is the main component of the Cu-based alloy forming the lining layer 11 and a Bi powder forming the Bi phase 17. The size of the particles of the Bi phase 17 in the lining layer 11 is controlled by changing the particle size of the Bi powder used as the material. The size of the particles of the Bi phase is adjusted, for example, by blending particles classified as having a particle size of 75 μm or less or 38 μm or less.

[0019] In the primary sintering of sintering these mixed powders, the sintering temperature is set to 600°C to 800°C, which is about 4 / 5 of the conventional sintering temperature. Thereby, in the primary sintering of the powders, the powders can be bonded to each other with relatively fine neck formation, and the Cu-based lining layer 11 becomes porous. As a result, the particles of the Bi phase 17 contained in the lining layer 11 after the primary sintering exist in a finely dispersed state in the porous portion of the lining layer 11. Thereafter, post-treatment such as rolling is performed to produce the lining phase 11.

[0020] The post-treated lining layer 11 is washed with an acid for the purpose of removing the oxide film at the interface 16. Thereby, the Bi phase 17 contained in the lining layer 11 is removed prior to Cu, which is the main component of the lining layer 11, due to the difference in ionization tendency. The portion where the Bi phase 17 is removed at the interface 16 forms a recess 18. The lining layer 11 washed with an acid is washed with water or the like, and then a coating layer 12 is formed. The coating layer 12 is formed, for example, by plating with Ni or a Ni alloy. In the case of this embodiment, the lining layer 11 is not subjected to strict washing other than washing with an acid and water. That is, a small amount of Bi may remain in the recess 18 or the like in the lining layer 11 of this embodiment. The coating layer 12 formed by plating or the like partially penetrates into the recess 18. Thereby, the coating layer 12 forms an intrusion portion 19 that penetrates into the lining layer 11 side.

[0021] Hereinafter, an example of the sliding member 10 of this embodiment will be described. In the examples and comparative examples, the sliding member 10 was evaluated based on the adhesion strength between the lining layer 11 and the coating layer 12. The evaluation of the adhesion strength was performed by the cross-cut evaluation specified in "JIS K5600-5-6" for evaluating the adhesion strength of plating. Since the conditions of the heat treatment temperature and time set before the implementation of the cross-cut evaluation according to the regulation are strict evaluation conditions, "Classification 0", "Classification 1" and "Classification 2" were considered qualified. After the test pieces of the examples and comparative examples were prepared based on the above manufacturing method, a heat treatment at 150°C for 500 hours was applied to reproduce the use conditions, and then the adhesion strength was evaluated.

[0022] Figure 4 shows the evaluation of the influence of the ratio value R on the adhesion strength. In Examples 1 to 3 and Comparative Example 1, the concentration C of Bi contained in the lining layer 11 is all set to 2.0 mass%. As shown in Examples 1 to 3, if the ratio value R is in the range of 1.00 ≦ R ≦ 9.00, it is "Classification 2", and it can be seen that it does not affect the adhesion strength. On the other hand, Comparative Example 1 with a ratio value R greater than 9.00 becomes "Classification 3", and it can be seen that the adhesion strength decreases. The lower limit of the ratio value R is set to 1.00 in consideration of the workability of the sliding member 10, particularly the machinability.

[0023] Figure 5 shows the evaluation of the influence of the maximum area S1 of the Bi phase 17 on the adhesion strength. In Examples 4 to 7, the concentration C of Bi contained in the lining layer 11 is all set to 2.0 mass%. As shown in Examples 4 to 7, if the ratio value R is constant, the smaller the maximum area S1 of the Bi phase 17, the higher the adhesion strength. However, as described above, if the maximum area S1 of the Bi phase 17 becomes too small, it will affect the workability of the lining layer 11. Therefore, the maximum area S1 of the Bi phase 17 is preferably 20 μm 2 or more.

[0024] FIG. 6 shows an evaluation of the influence of the maximum area S2 of the intrusion portion 19 on the adhesive strength. In Examples 8 to 11, the concentration C of Bi contained in the lining layer 11 is all set to 2.0 mass%. As shown in Examples 8 to 11, when the ratio R is constant, it shows that the smaller the maximum area S2 of the intrusion portion 19, the higher the adhesive strength.

[0025] FIG. 7 shows an evaluation of the influence of the concentration C of Bi added to the lining layer 11 on the adhesive strength. When the value of the ratio R is constant, it shows that the smaller the concentration C, the higher the adhesive strength. However, as described above, the concentration of Bi affects the workability of the lining layer 11. Therefore, it is premised that Bi is added to the lining layer 11, and from a practical point of view, the lower limit value is set to 0.1 mass%.

[0026] The present invention described above is not limited to the above embodiments, and can be applied to various embodiments without departing from the gist thereof.

Explanation of Reference Numerals

[0027] In the drawings, 10 represents a sliding member, 11 represents a lining layer, 12 represents a coating layer, 17 represents a Bi phase, 19 represents an intrusion portion, and 20 represents an observation region.

Claims

[

1. ] A sliding member comprising: a lining layer formed of any one of a Cu-based alloy, a Sn-based alloy, or an Al-based alloy containing 0.1 mass% to 2.0 mass% of Bi and having a thickness of 0.1 mm to 1.5 mm and containing a Bi phase; a coating layer formed of Ni or an alloy containing 70 mass% or more of Ni and having a thickness of 1 µm to 5 µm, provided on the surface of the lining layer, and forming an intrusion portion partially intruding into the lining layer side at the interface with the lining layer; wherein the ratio value R = S1 / S2 of the maximum area S1 of the Bi phase contained in the lining layer and the maximum area S2 of the intrusion portion intruding into the lining layer in any observation region including the intrusion portion at the interface between the lining layer and the coating layer is 1.00 ≤ R ≤ 9.

00. A sliding member. [

2. ] The maximum area S1 of the Bi phase is the sliding member according to Claim 1. S1 ≤ 810 μm ２ which is [

3. ] The maximum area S2 of the intrusion portion is the sliding member according to Claim 1. 20 μm ２ ≤ S2 ≤ 90 μm ２ is satisfied [

4. ] The concentration C of Bi contained in the lining layer is 0.1 mass% ≤ C ≤ 1.5 mass%, the sliding member according to Claim 1. ​

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