JPH0559596A - Composite plating method and device - Google Patents

Abstract

PURPOSE:To provide the composite plating method and device which allow the speeding up, heretofore being arduous, of composite dispersion plating in composite electroplating, can economically treat even a large-sized work, such as large-diameter piston ring in particular, with the compact device and are adequate for the outer peripheral sliding surface of the ring required to have good wear resistance, seizure resistance and initial fit property. CONSTITUTION:This device includes an anode body 20 which supplies a suspended plating liquid by coming into contact with the surface to be plated of a rotatably supported base material (piston ring of the work 10 in the embodiment) and a cathode terminal 30 which is energized by receiving spring force to come into contact with the surface to be plated of the base material. This method forms a composite plating layer by subjecting the surface to be plated of the base material to an acidic activation electrolysis by this device after degreasing the surface to be plated, then by rotating the base material to bring the anode body 20 into contact with the surface to be plated and electrodepositing the surface to be plated suspended with metallic hard particles or solid lubricant particles while rubbing the surface to be plated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is particularly suitable for plating formed on the outer peripheral sliding surface of a piston ring, and a composite plating method and apparatus for forming a composite dispersed plating layer of hard metal particles or solid lubricant particles. Regarding

[0002]

2. Description of the Related Art In recent years, attention has been paid to a composite plating method capable of forming a plating film having excellent wear resistance, seizure resistance and initial familiarity on a metal surface. This composite plating method is a method of dispersing hard particles such as silicon nitride and silicon carbide or solid lubricant particles such as molybdenum disulfide and boron nitride in a metal matrix such as nickel, and is called dispersion plating. Sometimes. That is, by appropriately selecting the type, size and amount of dispersed particles, a film having excellent wear resistance, seizure resistance, corrosion resistance and initial familiarity can be formed. At present, it has already been adopted as a plating method suitable for products that slide like cylinders and piston rings.

[0003]

Generally, in the composite plating method, a work is immersed in a plating bath in which hard particles or solid lubricant particles are uniformly suspended. By swinging or rotating the work in the immersed state, a plating film is deposited on the surface of the work by an electrolytic method or an electroless method. However, in the conventional method of immersing the work in the plating bath, if the current density is increased in order to increase the electrodeposition rate, there is a problem that the content of dispersed particles decreases. Also, especially when the work is a piston ring with a large ring diameter such as for ships and generators, the plating bath becomes large and the suspended particles in the bath are uniformly dispersed, and a composite dispersion is formed in the film. Difficult to do uniformly. Therefore, there is a problem that it becomes difficult to increase the dispersed content. Therefore, the object of the present invention is to speed up the composite dispersion plating in the composite electrolytic plating, which is a conventional problem,
Especially for large workpieces such as large diameter piston rings, it can be economically processed with a compact device, and is suitable for ring outer peripheral sliding surfaces that require good wear resistance, seizure resistance, and initial familiarity. An object is to provide a suitable composite plating method and its apparatus.

[0004]

The composite plating method according to the present invention comprises a step of electrolytically cleaning and degreasing a surface of a base material to be plated,
Process of acid-activated electrolysis of degreased surface to be plated, rotating base material and bringing anode body into contact with the surface to be plated, and plating with plating solution in which hard metal particles or solid lubricant particles are suspended while rubbing Forming a composite dispersion plating layer by electrodeposition on the surface. Here, the metal hard particles include metal carbide, metal nitride, metal oxide, and the like. Further, for the solid lubricant particles, boron nitride, molybdenum disulfide, graphite fluoride, Teflon, or the like can be used. A piston ring is suitable for the base material, and at least the outer peripheral surface of the piston ring can be the surface to be plated. The plating apparatus of the present invention, the anode body which is in contact with the surface of the base material rotatably supported to supply the suspension plating solution, and the surface of the base material which is to be plated are brought into contact with each other by a spring force to conduct electricity. And a cathode terminal in which a suspension plating solution is circulated and injected, a graphite anode which is provided in the case and is porous-formed so that the plating solution can penetrate, and the anode body is bonded to the graphite anode. And a fibrous friction material capable of penetrating the suspension plating solution that comes into contact with the surface to be plated of the base material and rubs, and the suspension plating solution is electrodeposited on the surface of the rotating base material to be plated. Then, the composite dispersed plating layer is formed.

[0005]

Function: The plated surface of the base material is degreased, and the degreased plated surface is subjected to acid activation electrolysis. The suspension plating solution is electrodeposited by bringing the anode body into contact with the surface to be plated of the rotating base material and rubbing. Since the surface to be plated is activated by rubbing it, the plating speed can be increased, and the composite dispersed plating layer formed by electrodeposition has excellent wear resistance, seizure resistance, and initial familiarity.

[0006]

EXAMPLE An example in which the composite plating method according to the present invention is applied to a piston ring will be described below with reference to the drawings.
1 and 2 have, for example, specifications of nominal diameter: 120 mm,
1 shows a top ring (hereinafter referred to as a work) 10 of a general truck automobile engine made of steel having a width of 3 mm and a thickness of 4.5 mm.

FIG. 3 shows an apparatus for plating the outer peripheral sliding surface of the work 10. In the plating apparatus, a large number of workpieces 10 are stacked with their axes aligned to form a single tubular shape, which can be rotatably supported. Further, the anode body 20 pressed against the entire outer peripheral sliding surface of the work 10 of such a laminated body is arranged, and the anode body 20 has a curved case 21 along the curvature of the work, and is provided in the case 21. The entire anode body 20 is fixed via a support rod 22 which is an anode electrode. A plating solution is injected into the case 21 from a solution cooling tank 24 through an injection pipe 23. Further, the case 21 is filled with a graphite anode 25 which is an electrode, and the porous graphite anode 25 can permeate the plating solution sent from the injection pipe 23.
The surface of the graphite anode 25 facing the work 10 has a concave curved surface, and along this concave curved surface, chemical fibers such as vinyl fibers, or a friction material 26 such as a mesh non-woven fabric or a felt material is adhered. The friction material 26 is also capable of penetrating the plating solution, and the plating solution is applied by bringing the friction material 26 into contact with the outer peripheral surface of the rotating work 10.

A tray 27 for collecting the plating solution dropped from the work 10 during the plating process is arranged immediately below the work 10, and the plating solution collected in the tray 27 is passed through a filter 28 by a pump 29. A circulation system for returning to the solution cooling tank 24 is adopted.

On the other hand, a cathode terminal 30 is arranged at a position where it can come into contact with the work 10. The cathode terminal 30 is energized, and the cathode 31 can be pressed into contact with the outer peripheral surface of the rotating work 10 by a spring 31. is there.

Next, the steps of plating the work 10 by the composite plating method using the above-described plating apparatus will be described in order. First, in [Step 1], the work 1 to be plated is prepared according to the bath composition and conditions shown in the following "Table 1".
The outer peripheral surface of No. 0 is electrolytically cleaned and degreased.

[Table 1] Next, as [Step 2], the work 10 that has been degreased
The outer peripheral surface is subjected to acidic activation electrolysis with the bath composition and conditions shown in "Table 2". (Hereafter this page margin)

[Table 2]

Next, in [Step 3], as shown in FIG. 3, the friction material 26 of the anode body 20 is pressed and brought into contact with the outer peripheral surface of the rotating work 10 by transmitting the drive. At the same time, the cathode terminal 30 is brought into contact with the outer peripheral surface of the work 10 by the urging force of the spring 31, and the electric circuit with the anode body 20 is energized. The plating solution is injected into the case 21 of the anode body 20 from the solution cooling tank 24 through the injection pipe 23. The composition of the plating solution is a suspension of hard particles or solid lubricant particles shown in "Table 3". (Margins below this page)

[Table 3] (Hereinafter, this page margin) The plating solution injected into the anode body 20 permeates the friction material 26 from the graphite anode 25. Workpiece 1 rotating in this way
While rubbing the friction material 26 on the outer peripheral surface of 0,
100 μm of the dispersion composite plating of Co—Ni—P alloy chromium oxide is electrodeposited on the outer peripheral surface of. Workpiece 1 in rotation
The outer peripheral surface of No. 0 is activated by the friction material 26 being constantly slid on it, and a certain amount of the particle suspension plating solution is supplied to this active surface through each member on the anode body 20 side.

Further, in [Step 4], the outer peripheral surface of the work 10 which has been electrodeposited in [Step 3] is finished by, for example, buffing, and then heat treatment is performed at 400 ° C. for 1 hour.

Here, the hard particles contained in the plating solution are
Metal carbide, metal nitride, metal oxide and the like are suitable.
Further, the solid lubricant particles are preferably boron nitride, molybdenum disulfide, fluorinated graphite, Teflon, or the like. In consideration of wear resistance and seizure resistance, the size of these particles is set to 0 in order to stably supply the plating solution to the contact surface gap between the friction material 26 of the anode body 20 and the outer peripheral surface of the work 10. 5
˜5.0 μm is preferable. The amount of the dispersant suspended in the plating solution is preferably 5 to 50 g / l in order to obtain a high content of dispersed particles and a uniform dispersed state. 50 g / l
In the above case, the dispersed particles may block the contact surface gap between the work 10 and the friction material 26 or the piping of the circulation system. When it is 5 g / l or less, the content of the dispersed particles contained in the coating becomes low, resulting in deterioration of abrasion resistance and scuffing resistance. Further, if dispersed particles in the suspension plating solution are deposited between the outer peripheral surface of the work 10 and the graphite electrode 25, the electric resistance may increase and the deposition may decrease.

Next, in order to compare the superiority of the composite plating method of the present invention adopted for the top ring which is the work 10, a top ring of the same material and shape as the work 10 of the embodiment is designated as "Comparative Example 1". A hard chrome plating electrodeposited on the outer peripheral surface with a thickness of 100 μm was prepared. Further, as “Comparative Example 2”, a top ring of the same material and shape was prepared, and a bath composition in which the content of particles suspended in the homogeneous plating solution by the conventional immersion plating method was increased to 100 g / l was prepared. A plating process was performed. That is, Co-
Ni-P alloy chromium oxide dispersion composite plating with a thickness of 100
It was electrodeposited with a thickness of μm. After electrodeposition of both samples of Comparative Examples 1 and 2, the outer peripheral surface of the sample was finished and heat treatment was performed at 400 ° C. for 1 hour as in the above-mentioned [Step 4].

A total of three samples of Examples and Comparative Examples 1 and 2 were actually worn as a top ring of a 6-cylinder water-cooled 4-cycle engine, and after running-in, a rotation speed of 43 at full load.
A durability test of 200 hours operation at 00 rpm was performed. "Table 4" shows the results of measuring the amount of wear by observing the sliding surface between the top ring and the cylinder of each sample.

[Table 4] As is clear from "Table 4", in the case of the samples of the examples according to the present invention, the amount of wear was extremely reduced as in the case of the mating cylinder in comparison with Comparative Examples 1 and 2, and the surface condition was good. It has excellent wear resistance and seizure resistance.

[0016]

As described above, the composite plating method according to the present invention is suitable for the sliding surface of a sliding member such as a piston ring, and the outer peripheral surface of the piston ring, which is a workpiece, is rubbed during the plating process. Since it is rubbed with the material, activation of the electrodeposition interface is promoted. That is, since the electrodeposition is carried out while being activated, the adhesion is good, the content rate of the particles is increased, the electrodeposition plating rate is also increased, and the obtained composite plating layer is dense and has abrasion resistance and resistance. Excellent in printability and initial familiarity.

[Brief description of drawings]

FIG. 1 is a plan view of a piston ring (top ring) of an embodiment to which a composite plating method according to the present invention is applied.

FIG. 2 is a cross-sectional view of the piston ring taken along the line AA in FIG.

FIG. 3 is a schematic view of a composite plating apparatus of the present invention.

[Explanation of symbols]

10. ． Piston ring, 11. ． Composite dispersed plating layer,
20. ． Anode body, 21. ． Case, 23. ． Plating solution injection pipe, 25. ． Graphite anode, 26. ． Friction material, 30. ． Cathode terminal, 31. ． Spring, 24. ． Solution cooling tank, 27. ． Collection tray

Claims (5)

[Claims] 1. A step of electrolytically cleaning and degreasing a plated surface of a base material, a step of subjecting the degreased plated surface to acid activation electrolysis, and rotating the base material to bring an anode body into contact with the plated surface. A composite plating method comprising a step of forming a composite dispersed plating layer by electrodepositing a plating solution in which hard metal particles or solid lubricant particles are suspended while rubbing on a surface to be plated. 2. The composite plating method according to claim 1, wherein the hard metal particles are any of metal carbide, metal nitride and metal oxide. 3. The composite plating method according to claim 1, wherein the solid lubricant particles are any one of boron nitride, molybdenum disulfide, graphite fluoride and Teflon. 4. The composite plating method according to claim 1, wherein the base material is a piston ring, and at least the outer peripheral surface of the base material is the surface to be plated. 5. An anode body, which is in contact with a surface of a base material that is rotatably supported and which supplies a suspension plating solution, and a surface of the base material, which is to be plated, are contacted by a spring force to be energized. The anode body includes a cathode terminal, and a case where the suspension plating solution is circulated and injected, a graphite anode that is provided in the case and is porous-formed so that the plating solution can penetrate, and the anode body is joined to the graphite anode. A fibrous friction material capable of penetrating the suspension plating solution that comes into contact with the surface to be plated of the base material and rubs, and the suspension plating solution is electrodeposited on the surface of the rotating base material to be plated. A plating apparatus for forming a composite dispersed plating layer.