JPS63297598A - Wear-resistant sliding member - Google Patents

Abstract

PURPOSE:To obtain a sliding member excellent in wear resistance, seizure resistance, and corrosion resistance, by forming a composite plating layer in which WC hard grains are dispersed in a specific area ratio into an alloy matrix having a specific composition consisting of Co, P, and Ni on a sliding surface. CONSTITUTION:A composite plating layer in which WC hard grains (0.5-10mum) are dispersed by 5-40area% in an alloy matrix consisting of 10-50wt.% Co, 1-15wt.% P, and the balance Ni is formed on the sliding surface of a metallic sliding parts. Further, it is preferable to disperse the grains of solid lubricant, such as MoS2, into the above WC hard grains by 5-30area%. Moreover, it is desirable to apply nitriding treatment to the above-mentioned composite plating layer so as to improve the toughness of the film matrix. By this method, the wear-resistant sliding member having a film layer excellent in wear resistance, seizure resistance, and corrosion resistance on the sliding surface can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to wear-resistant sliding members such as piston rings having a hard particle dispersed nickel-phosphorus-cobalt plating layer.

Conventional technology and its problems Wear-resistant sliding members, such as piston rings that slide at high speed, are widely used with hard chrome plating to increase wear resistance. In addition to the fact that it takes a considerable amount of time to complete the process, it also requires a large amount of money to take measures to prevent pollution caused by waste liquid from plating, which increases the cost of plating. When used in , there were problems with wear resistance, seizure resistance, corrosion resistance, etc.

In order to solve the above problems, attention has been paid to composite plating in which hard particles such as nitrides, carbides, or oxides are dispersed in an alloy matrix such as nickel-phosphorus. This is called composite plating or dispersion plating, and by appropriately selecting the type, size, and amount of dispersed particles, a film with excellent wear resistance, seizure resistance, and corrosion resistance can be created. It has already begun to be used in sliding members such as cylinders and piston rings.

However, when used in a high-speed engine, the coating tends to become brittle due to the effects of heat load. In addition, there is little wear on both the coating itself and the mating material, and even if the coating is nitrided after forming the plating coating, its functionality is fully satisfied.
It has been desired to develop a manufacturing method that forms a nitrided layer with excellent wear resistance on the sliding surface other than the coating.

The present invention solves the problems of conventional composite plating and provides a sliding member having a coating layer on its sliding surface with excellent wear resistance, seizure resistance, and corrosion resistance.

Means for Solving the Problems and Their Effects According to the present invention, there is provided a sliding member in which a composite plating layer is formed on the sliding surface of a metal sliding component, wherein the composite plating layer is made of cobalt: lo~50.
Tungsten carbide hard particles (0,
Provided is a wear-resistant sliding member having 5 to 40 area % of particles (5 to 10 μm) dispersed therein.

Phosphorus contained in the alloy matrix increases the hardness of the film by performing a thermosetting treatment, and as a result has an excellent effect on improving the wear resistance and further corrosion resistance of the film. The amount of phosphorus is
1 to 15% by weight is good. If the amount of phosphorus is less than 1% by weight, the above effect will be small, and if it exceeds 15% by weight, the film will become brittle, and the impact strength and adhesion of the film will decrease.

Seizure resistance is improved by adding cobalt to the alloy base.
Abrasion resistance and corrosion resistance are improved, and film strength is also increased.

In the world of cobalt, 10 to 50% by weight is good. The amount is 10
If it is less than 50% by weight, the effect will be small, and if it exceeds 50% by weight, there will be no significant change in the effect, which is not economical.

Tungsten carbide (W) dispersed in the alloy matrix
C) The particle size of the hard particles is 0.5 to 10 μm, and the product is 5 to 10 μm.
40 area% is good. Tungsten carbide (WC)
If the particle size of the hard particles is 0.5 μm or less or 5 area % or less, the effect on wear resistance is small. Also, the particle size is 10
If it exceeds .mu.m or 40 area %, the strength of the film will actually decrease and the wear of the mating material will increase. The particle size of the solid lubricant particles to be mixed is 0.5 to 10 μm.
However, the amount is preferably 5 to 30% by area. If the solid lubricant particles have a particle diameter of 0.5 μm or less or a particle size of 5 area % or less, the effect in terms of wear resistance and seizure resistance is low. In addition, the particle size is 10 μm
If the amount is more than 30% by area, the strength of the coating will be reduced and it will become brittle and easily fall off. As solid lubricant particles, molybdenum disulfide, tungsten disulfide, boron nitride, etc. are preferable.

In addition, the conventional composite plating layer has a 550 to 6
When the nitriding treatment was performed at 00°C, the wear resistance and seizure resistance of the coating decreased, but in the case of the plated layer, there was no decrease in these.
Rather, the toughness of the film increases, and the interlayer strength of the film, which causes peeling between the film layers, is improved. Therefore, if the glabellar strength of the coating is a problem in use, it is desirable to perform a gas nitriding treatment or the like after forming the plating layer to improve the toughness of the coating base. Furthermore, a nitrided layer can be formed on the sliding surface other than the plating layer film.

For example, nitriding treatment is performed to prevent wear on the upper and lower surfaces of piston rings, but this nitriding treatment can also be performed.

Example The tip end surface of steel material for piston ring is 5 mm x 5 mm.
As a first step, a nickel plating with a thickness of 5 μm was formed on the sliding surface of a steel test piece using the usual nickel strike plating method, and then as a second step, an electroplating method was applied to the sliding surface under the conditions shown in Table 1. A tungsten carbide (WC) dispersed 2.7 K phosphorus-cobalt plating layer was formed with a thickness of 120 μm.

As a third step, each test piece obtained by the above method was heated at 400°C for 1
Heat-cured for a period of time. This type of nickel-cobalt
The e-alloy plating layer is usually subjected to heat hardening treatment,
This heating temperature is generally 200 to 600°C. In addition, as another step, in the heat hardening treatment step of the present invention, a nitrided layer was formed on the sliding surface other than the coated portion at the same time as the heat hardening of the film by nitriding treatment.

Table 2 shows the results measured with a micro-Vickers hardness meter and the composition of the plating film.

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 a disc 3 made of cast iron FC25, which is used as a cylinder material, etc., and whose sliding surface 2 has been honed is removably attached to a stator holder 1, and a lubrication hole 4 is inserted into the center from the back side. Lubricating oil is applied to the stator holder 1 by a hydraulic device (not shown) so that a pressing force is applied to the stator holder 1 toward the right in the figure at a predetermined pressure. A test piece 7 is attached to each of the four holes carved at equal intervals on the circumference of the test piece holder 6, which is mounted on the rotor 5 facing the disk 3 and is concentric with the rotation axis. Ta. The 5 x 5 mm square tip end face of each test piece, which has been subjected to a predetermined surface treatment, contacts the sliding surface 2 of the disk 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 test piece 7 slides on the disk 3 by a predetermined sliding distance.The wear resistance is measured by the amount of wear of the test piece 7 and the stator disk 3. Assess gender.

Furthermore, when the rotor 5 is rotated, a torque F is generated in the stator holder l due to the friction between the test piece 7 and the disk 3 as shown in the figure, so this torque F is applied to the load cell 9 via the spindle 8, and the pressing force is The change in the torque F due to the change in is read by the dynamic strain meter 10, and it is assumed that seizure occurs when the torque F suddenly increases, and the seizure resistance is evaluated based on the pressing force at that time.

In addition to the test piece obtained in the above example, test piece 7 also contained hard chromium plating, which is generally used for wear-resistant surface treatment, molybdenum thermal spraying, which has excellent wear resistance and seizure resistance, for comparison. Similar tests were conducted on WC-dispersed nickel-phosphorus plating that did not contain cobalt.

a) Dust (318
2 types) added at 0.2 g/1 f, one temperature/c
While applying a pressing force of +1), the friction speed of test piece 7 was increased by 3.
~5m/sec, and the rotor 5 was rotated until the sliding distance reached 1)00k.

The test results are shown in Table 3 below.

b) Seizure resistance test The same lubricant as that used in the wear test was used, and the stator holder 1 was first supplied with a hydraulic pressure of 40 kg/ca toward the rotor.
The rotor 5 is rotated for 3 minutes at a friction speed of 8 m/sec, and the pressure is increased to 10 kg/sec in this way.
Increase the torque stepwise by cd and hold for 3 minutes each, record the change in torque F with the dynamic strain meter IO via the load cell 9, and calculate the contact surface pressure from the pressing force when the torque suddenly increases. is the generated surface pressure.

The test results are shown in Table 4 below.

C) Actual machine test Next, the nominal diameter x width x thickness is 86 x 2. OX3
．． The composite plating of the present invention was applied to the first pressure ring made of 6mm steel, and it was assembled into a 4-cylinder diesel engine with a bore diameter of 86mm and a water-cooled supercharger.
A high-speed durability test was conducted for 100 hours, and the wear of the piston ring sliding surface and the inner circumferential surface of the cast iron (Fe12 material) cylinder liner was measured. The composition of the composite plating layer of this piston ring is: Cobalt: 25% by weight, F: 4% by weight,
Tungsten carbide: average particle size 0.8 μm, 20 area% with the rest being nickel, and composite plating layer compositions of tungsten carbide particles and solid lubricant composites: cobalt: 25% by weight, phosphorus: 4% by weight, tungsten Carbide: average particle size 0.8 μm, 20 area%,
Molybdenum disulfide was used as the solid lubricant symmetry #, and the average particle size was 2.0 μm, 10UB volume %, and the rest was nickel. One was heat-hardened at 400°C, and the other was subjected to gas nitriding at 570°C for 3 hours. I used something.

The test results are shown in Figure 2. As comparative examples, tests were also conducted on hard chromium plating, molybdenum thermal spraying, and tungsten carbide dispersed nickel-phosphorus composite plating that does not contain cobalt, obtained by the same method as that used in the liner abrasion tester.

From Table 3.4 and Figure 2, nickel-cobalt of the present invention
Compared to conventional plating layers, the phosphorus composite plating layer has higher wear resistance and
It can be seen that the seizure resistance is excellent. Furthermore, it is a surface treated layer that causes less wear on the mating material, no breakage, no peeling or falling off of the coating, no wear on the side surfaces, and is suitable for sliding members such as piston rings.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional photograph of the piston ring plating layer of the present invention obtained by electroplating. FIG. 2 is a graph showing the amount of wear as a result of an actual machine test. 3 and 4 are schematic diagrams of the abrasion tester. In the figure: 1... Stator holder, 2... Sliding surface, 3... Circular counter, 4... Lubrication hole, 5... Rotor, 6... Test piece holder, 7... ...Test piece, 8...Spindle, 9...Load cell, 10...Dynamic strain diameter. Agent: Patent Attorney Hideaki Kuwahara (Director)
Procedural Dispute Book September 1988 Kunio Ogawa, Commissioner of the Patent Office 1, Indication of the Case Japanese Patent Application No. 131467/1982 2, Name of the Invention Wear-resistant Sliding Member 3, Person Making Amendment Case Relationship with Patent applicant Address: 1-13-5 Kudankita, Chiyoda-ku, Tokyo Name: Riken Co., Ltd. Representative
Hajime Mori 4, Representative 〒105

Claims (3)

[Claims] (1) A sliding member in which a composite plating layer is formed on the sliding surface of a metal sliding component, the composite plating layer being cobalt: 10
A wear-resistant sliding member comprising 5 to 40 area % of tungsten carbide hard particles (0.5 to 10 μm) dispersed in an alloy base consisting of ~50 weight %, phosphorus: 1 to 15 weight %, and the remainder nickel. (2) 5-30% in tungsten carbide hard particles
% of the solid lubricant particles are dispersed therein.The wear-resistant sliding member according to claim 1, wherein the solid lubricant particles are dispersed in an area of %. (3) The wear-resistant sliding member according to claim (1), wherein the composite plating layer is nitrided.