JPS6115997A - Wear resistant sliding member and its manufacture - Google Patents

Abstract

PURPOSE:To improve the wear and seizing resistances of a sliding member by forming a composite layer contg. hard particles dispersed under prescribed conditions in the Ni matrix contg. a prescribed percentage of P on the sliding surface by plating. CONSTITUTION:A composite plating bath is prepd. by suspending 5-40g/l hard particles of 0.5-10mum average particle size in an Ni-P alloy electroplating soln. of 0.3-3pH contg. 5-130g/l nickel chloride and 5-30g/l phosphorous acid. The sliding surface of a sliding member is plated in the composite plating bath to obtain a sliding member having a composite layer contg. 5-30vol% hard particles of 0.5-10mum average particle size dispersed in the Ni matrix contg. 5-12% P.

Description

[Detailed description of the invention]

Technical Field of the Invention The present invention relates to a wear-resistant sliding member having a hard particle dispersed nickel plating layer and a method for manufacturing the same. 2. Prior Art and Problems Recently, a composite plating method that forms a wear-resistant and seizure-resistant film on a metal surface has been attracting attention. This method is a plating method in which hard particles such as silicon nitride and silicon carbide are dispersed in a metal matrix such as nickel, and is called composite plating or dispersion plating. By selecting an appropriate material, it is possible to form a film with excellent wear resistance, seizure resistance, and corrosion resistance, and it has already begun to be used for cylinders and sliding members such as piston rings. Nickel-phosphorus composite plating includes an electroless method and an electrolytic method. An example of the former is silicon nitride in an electroless nickel plating bath containing nickel salt and hypophosphite as a reducing agent.
This is a method in which nickel, phosphorus, and hard particles are dispersed using the reducing power of hypophosphite ions while suspending and dispersing hard particles such as silicon carbide. As an example of the latter, hard particles such as silicon nitride and silicon carbide are suspended and dispersed in an electrolytic nickel plating bath mainly composed of nickel sulfate, nickel sulfamate, etc., and nickel and This is a method of dispersing phosphorus and hard particles. Although the electroless composite plating method has the property of being able to obtain a uniform film thickness even on products with complex shapes, it has the following disadvantages. In other words, the operating temperature is high, the bath composition changes greatly, when the liquid gets old it tends to cause powdery precipitation and the liquid cannot be used permanently, the precipitation rate is slow, it is difficult to arbitrarily change the phosphorus content, etc. . On the other hand, the electrolytic composite plating method has a fast deposition rate even at low temperatures, has a long bath life, and because phosphorous acid and hypophosphorous acid do not participate in the reduction of metal ions, there is less consumption of phosphorous groups such as phosphorous acid and sodium hypophosphite. Although it has the advantage of being able to adjust the phosphorous content by adjusting the amount of phosphorous acid and hypophosphorous acid added to the plating bath, it is difficult to obtain a uniform film thickness on products with complex shapes. There are drawbacks such as not being able to raise the price. Purpose of the Invention The present invention improves both the phosphorus content and the hard particle content, which were the problems of conventional composite electrolytic nickel plating, and provides a sliding surface with a hard coating layer with excellent wear resistance on the sliding surface. It provides a moving member. 20 Structure of the Invention The present invention relates to a phosphorus compound in an electrolytic nickel plating solution. The present invention relates to a sliding member having a film containing a high content of phosphorus and hard particles by maintaining appropriate pH values of nickel chloride and a plating solution, and a method for manufacturing the same. The phosphorous compound contained in the plating solution is preferably phosphorous acid, and the amount of phosphorous acid is suitably 5 to 30 g/l. If it is less than 5g71, the content of phosphorus precipitated in the film will be as low as 4% or less, resulting in poor wear resistance and corrosion resistance. On the other hand, if it exceeds 30 g/1, the content of phosphorus deposited in the plating film will exceed 12%, which makes the film brittle. The amount of nickel chloride contained in the plating solution is 5 to 130 g.
/l is appropriate. If the amount of nickel chloride is small,
The amount of nickel precipitated is slow, and the dissolution of nickel ions is reduced. Moreover, as the amount increases, the effect of electrodeposition of nickel increases, and therefore the content of phosphorus decreases relatively. As the pH value of the plating solution decreases, more phosphorus is precipitated, but on the other hand, the precipitation of hard particles becomes worse and the electrodeposition rate becomes slower. From this, a pH value of 0.3 to 3 is appropriate. Next, a plating apparatus applied to the present invention will be described. The amount of eutectoid hard particles is related to the pH value of the plating solution.
Hard particles precipitate relatively easily when the pH is high. This plating solution has a low pH value (conventional methods tend to reduce the amount of hard particles dispersed). Therefore, it is desirable to use a plating apparatus as shown in FIG. 1(b). In this example, the workpiece 1, which was conventionally vertical as shown in Figure 1(a), was changed to horizontal as shown in Figure 1(b), and this was slowly rotated at 1 to 10 ppm, so that the hard particles formed into rings. It was made to be more likely to be deposited on the outer peripheral surface. In addition, in the method shown in Figure 1 (b), hard particles and plating liquid enter the bearing part, which can easily cause wear and corrosion of the bearing part. It is preferable to position it above the surface to be covered. In this case, it is necessary to continuously moisten the workpiece by pouring plating solution onto it from above. E1 Example of the invention The tip end surface of the steel material for piston rings is 5 us X 5
As a first step, each sliding surface of a steel specimen of 100 mn was plated with a thickness of 10 mm using the usual nickel strike plating method.
The material was formed by forming μ nickel plating. Next, as a second step, each material was plated in Examples 1 and 2 under the conditions shown in Table 1. For comparison, plating of Comparative Examples A and B was applied to the same material using the method conventionally used by our company.

[Table 11] As the third step, the test piece obtained by the method of the above example was subjected to heat hardening treatment at 370° C. for 1 hour, and the following hardness test, seizure test, and wear test were conducted. This type of nickel-phosphorus alloy plating layer is usually subjected to heat hardening treatment, and the heating temperature is generally 200 to 450°C.
. a) Hardness test results The results measured using a micro Vickers hardness meter are shown in Table 2 below. Next, a wear resistance test and a seizure test of sliding surfaces according to the present invention will be explained. The test was conducted using a lidar one-type abrasion tester shown in FIGS. 3 and 4. The outline is that the stator holder 1 is made of a cast iron Fe12 material used as a cylinder material, etc., and the sliding surface 2 is honed.
is removably attached to the stator holder 1, and lubricating oil is supplied to the center from the back side through an oil fill hole 4, and a predetermined pressure is applied to the stator holder 1 toward the right in the figure by a hydraulic device (not shown). It is designed so that pressing force is applied. A test piece 7 is attached to each of four attachment holes carved at equal intervals on a circumference concentric with the rotation axis of a test piece holder 6 attached to the rotor 5 facing the disk 3, 5 x 5 m of test pieces, each with a specified surface treatment
The m-square tip end surface contacts the sliding surface 2 of the disc 3 and is rotated at a predetermined speed by a drive device (not shown). The test is conducted while lubricating oil at a constant temperature is supplied to the sliding surface from the oiling hole 4 on the stator side. In the wear test, the rotor 5 is rotated under a constant pressing force, and the wear resistance is measured by the amount of wear of the test piece 7 and the stator disk 3 when the test piece 7 slides on the disk 3 by a predetermined sliding distance. Assess gender. Also, when the rotor 5 is rotated, the friction between the test piece 7 and the disk 3 causes the stator holder No. 1 = to have a torque F as shown in the figure.
Therefore, this torque F is applied to the load cell 9 through the spindle 8, and the change in the torque F due to the change in the pressing force is read by the dynamic strain meter 10. If the torque F suddenly increases, it is assumed that seizure has occurred. Seizure resistance is evaluated based on the pressing force applied at that time. b) Wear test results Dust (JI
Using oil at a temperature of 80°C to which 0.2 g/L of 82 types) was added, it was supplied from the oil filling hole 4, and while applying a pressing force of hydraulic pressure of 10Q K g / cs'' to the stator holder 1 toward the rotor side. , the friction speed of test piece 7 was set to 3 to 5 m/s.
ee, and the rotor 5 was rotated until the sliding distance reached 1100K. The test results are shown in Table 3 below. [Table 3] C) Seizure test lubricant used was the same as that used in the wear test. Stator holder 1 has a hydraulic pressure of 40K facing the rotor side.
g/cm'' was applied, the rotor 5 was rotated for 3 minutes at a friction speed of 8 m/secC, and the primary pressing force was 50 Kg/am.
In this way, the pressing force was increased stepwise by 10 kg/am and held for 3 minutes each, and the change in torque F was recorded with the dynamic strain meter 10 via the load cell 9. The contact surface pressure was determined from the pressing force when the torque suddenly increased and was used as the surface pressure at which seizure occurred. The test results are shown in Table 4 below. From the above, it can be seen that the nickel-phosphorus dispersion plating layer of the present invention has superior wear resistance and seizure resistance compared to conventional plating layers. Furthermore, the present invention provides a surface treatment layer that is suitable for sliding members such as piston rings because it does not cause abrasion of the mating material.

[Brief explanation of drawings]

Figure 1 a) is a vertical plating equipment b) is a horizontal plating device 1 in the diagram is the workpiece Figure 2 shows a plating device with the bearing section higher than the plating liquid level. 1 in the diagram is the workpiece Figures 3 and 4 are wear test machines. 1 in the figure is the stator holder 2 is the sliding surface 3 is 1 circular plate 4 is the oil hole 5 is the rotor 6 is a test piece holder 7 is a test piece 8 is the spindle 9 is the load cell 1o is a dynamic strain meter (戊)　　　　　　　　　(b) Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1) A sliding surface having a composite plating layer in which hard particles with an average particle size of 0.5 to 10 μm are dispersed in a volume ratio of 5 to 30% in a nickel matrix containing phosphorus. A wear-resistant sliding member characterized in that the amount of phosphorus contained in the nickel base is 5 to 12%.2) Phosphorous acid is added to an electrolytic nickel plating solution containing 5 to 130 g/l of nickel chloride. To the electrolytic nickel-phosphorus alloy plating solution to which 5 to 30 g/l was added and the pH value was set to 0.3 to 3,
Electroplating is performed using a composite plating solution in which hard particles with an average particle size of 0.5 to 10 μ are suspended at 5 to 40 g/l. A sliding member having a composite plating layer containing 5 to 30% of phosphorus dispersed in the matrix, the amount of phosphorus contained in the base being 5 to 30%.
~12% Abrasion resistant sliding member manufacturing method