JPH04151073A - Sliding member - Google Patents

Abstract

PURPOSE:To improve wear resistance and seizure resistance of a slide surface by setting a ratio of a particle with an average grain size of 0.5-10.0mum contained in Ni composite alloy plating on the slide surface to a particle with an average grain size of 0.5mum to a value within a specified range. CONSTITUTION:An Ni composite alloy plated layer wherein one or two or more particles selected from rigid particles, such as metallic nitride particles, metallic carbide particles, and metallic oxide particles, metallic sulfide particles, and solid lubricating particles, such as boride particles, are dispersed is formed on the slide surface of a slide member. Further, particles with an average grain size of 0.5-10.0mum are dispersed in the Ni composite alloy plated layer in a ratio of five area percentage or less based on a plated layer and a total of particle with a fine average grain size of 0.5mum or less and large particles with an average grain size of 0.5-10.0mum are dispersed in the plated layer in a ratio of 2-30 area percentage based on the plated layer. This constitution improves wear resistance and seizure resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a sliding member in which a Ni composite plating layer in which hard particles are dispersed is formed on a sliding surface.

[Prior Art] Sliding members such as piston rings for internal combustion engines that are subjected to high temperatures and high loads are often plated with hard chrome on their sliding surfaces to improve wear resistance. However, chrome plating not only takes a long time to process, but also takes a lot of time to process plating waste liquid to prevent environmental pollution.
As a result, there was a problem in that the cost required for plating increased. Additionally, the use of chrome-plated sliding parts for components of engines that use high-lead gasoline or high-output, high-load engines may cause problems in terms of wear resistance, corrosion resistance, seizure resistance, etc. was there.

As a method for solving this problem, composite plating in which hard particles such as nitrides, carbides, oxides, etc. are dispersed in an N1-P alloy base is proposed in Japanese Patent Publication No. 5B-18080. According to this known plating, the types of dispersed particles,
By appropriately selecting the particle size and dispersion amount, it is possible to form a film with a certain degree of wear resistance, seizure resistance, and corrosion resistance, and it is already used for sliding parts such as cylinder liners and piston rings. .

In order to further reduce friction, plating with solid lubricant particles added in addition to the hard particles described above is also used.

Usually, the particles dispersed in the plating layer in this way have an average particle size of 0. Those having a diameter of 5 to 10.0 μm were used.

[Problem to be solved by the invention] N in the N1 multi-plated layer in which the above hard particles are dispersed
1-P alloy base tends to become brittle when subjected to high heat and high load, and its wear resistance, seizure resistance, etc. are not necessarily satisfactory when used as a sliding member of an engine operated at high speed under harsh conditions. It wasn't something.

Furthermore, the hard particles in the N1 double plating layer improve the wear resistance and seizure resistance of the plating layer by coming into contact with the mating material during sliding. Therefore, as the number of particles such as hard particles and solid lubricant particles dispersed in the Ni composite plating layer increases, the dispersion area of the particles increases accordingly, and the wear resistance and seizure resistance of the plating layer improve. .

However, when the dispersion rate of these particles exceeds a certain value, the proportion of the base material in the plating layer decreases, and the holding power of the plating layer to retain the particles and the like decreases. For this reason, the particles tend to fall off from the plating layer, making the plating layer brittle, resulting in a decrease in wear resistance and seizure resistance. Therefore, there is a certain limit to the improvement of wear resistance and seizure resistance by increasing the dispersion rate of the particles.

On the other hand, if fine particles are used, it is possible to increase the particle dispersion area without significantly increasing the dispersion rate (area percentage) of the particles in the plating layer, and as a result, the brittleness of the plating layer increases. However, fine particles are expensive and the cost of products using them increases.

In view of the above problems, the present invention improves the wear resistance and seizure resistance of the plating layer by dispersing two types of hard particles with different average particle sizes in the plating layer on the sliding surface at a predetermined ratio. It is an object of the present invention to provide a sliding member that has a plating film of a desired quality and is inexpensive to produce.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides hard particles made of metal nitrides, carbides, oxides, etc. and having a particle size of 10 μm or less, and sulfides, borides or A sliding member having, at least on its sliding surface, a former composite plating layer in which one or more particles selected from solid lubricant particles made of fluoride etc. and having a particle size of 10 μm or less are dispersed. , the average particle size dispersed in the Ni composite plating layer is 0. 5~
The dispersion rate of particles with a diameter of 10.0 μm is less than 5 area percent, and the dispersion rate of particles with an average particle size of less than 0.5 μm dispersed in the N1 double plating layer is 0.0 μm.
5-10. O) 2 to 30 in total with the dispersion rate of particles of tm
It is an object of the present invention to provide a sliding member characterized by a dispersion ratio that is an area percent.

[Operation] The sliding member according to the present invention has a predetermined ratio of particles with an average particle size of 0.5 to 10.0 μm and particles with an average particle size of less than 0.5 μm contained in the Ni composite plating on the sliding surface. Since it is within this range, the sliding surface has excellent wear resistance and seizure resistance. As a result, good results can be obtained even when the sliding member is used in an engine using high-lead gasoline or a high-output, high-load engine.

[Example] Hereinafter, a sliding member of the present invention used as a piston ring or the like of an engine will be described in detail.

The material as the base material of the sliding member of the present invention includes, for example, 0
．． Examples of use include steel containing 16 to 1.30% carbon and 12 to 19% chromium, or steel containing molybdenum and vanadium.

The sliding surface of the sliding member of the present invention contains hard particles selected from hard particles such as metal nitride particles, metal carbide particles, and metal oxide particles, and solid lubricant particles such as metal sulfide particles and boride particles. A Ni composite plating layer in which two or more particles are dispersed is formed.

Here, examples of hard particles and solid lubricant particles include the following. As hard particles, Si3N4, S
i C, W C, A l 20 s, zrO2, Cr
These are metal nitrides, metal carbides, metal oxide particles, etc. such as 2O5, and solid lubricant particles include, for example, MoS2.
(molybdenum disulfide), BN (boron nitride),
These include metal sulfides, borides, and fluorides such as polytetrafluoroethylene.

In addition, the upper layer of the Ni composite alloy has an average grain size of 0.
The above-mentioned particles of 5 to 10.0 μm (large particles) account for less than 5 area percent of the plating layer, and furthermore, particles with an average particle diameter of less than 0.5 μm (small particles), which are finer than conventionally used particles, are used. The above average particle size is 0. 5-10.0μm
The large particles are dispersed in such a way that the total area of the particles is 2 to 30 percent by area in the plating layer.

Here, the reason why the dispersion rate of the large particles is set to be less than 5 area percent is that if the dispersion rate is higher than this, the effect of dispersing the small particles together will not be produced, and the same effect as when only the large particles are dispersed will not occur. This is because the effects will no longer occur.

In addition, the reason why the total dispersion rate of large particles and small particles was set to 30 area percent or less was to prevent the Ni composite plating layer from becoming brittle, and the reason why the total dispersion rate of large particles and small particles was set to 2 area percent or more was because these particles were This is because the effect of dispersion does not occur.

When the particle size of the particles to be dispersed is 10 μm or more, the aggressiveness toward others becomes strong, causing the particles to fall off and impairing the abrasion resistance of the plating film.

Further, the amount of the hard particles or solid lubricant particles to be dispersed is appropriately selected within the above-mentioned range, taking into consideration the purpose and the like.

Furthermore, when the plated film in which the hard particles and solid lubricant particles are dispersed is subjected to heat treatment, the hardness and toughness can be increased. Since the rate of increase in hardness depends on the processing temperature, by appropriately selecting the processing temperature, the hardness of the Ni composite plating layer can be varied within a certain range to obtain a hardness that suits the usage conditions.

The thickness of the Ni composite plating film of the present invention is 5 μm to 250 μm.
The thickness is approximately μm, and the thickness is selected depending on the material, surface treatment, etc. of the outer peripheral sliding surface of the sliding member.

An example of a plating solution and plating conditions when manufacturing a sliding member according to the present invention is shown below.

Plating solution composition and plating conditions Nickel sulfate (NiSOm・6H20): 240g/liter Nickel chloride (N i Cl 2・6H20): 45
g/liter Hydrolic acid (HsB O3): 30g/liter Current density: 5A/dtd Liquid temperature: 55±1°C In addition, in the above table, hypophosphorous M (Hspo2) is added to the Watts bath as the electrolytic N1 plating bath. Trimethylamine borane (CHs) is used as a phosphorus additive and as a boron additive.
) s N B Hs: T MA B was used.

Next, the abrasion resistance, opponent attack resistance, and
The test results regarding seizure resistance are shown.

(Abrasion resistance, opponent attack test) The following test samples were used.

Sample A (comparative sample): H3P0□ was added to the plating solution as a phosphorus additive at 3 g/liter, and the average particle size of the dispersed particles was 1. 0μm Si3N
4 was added at 125 g/liter (15 volume percent), and after plating, the resulting sliding surface was coated with an average particle size of 1. 0μrn
Sliding member in which 15 area percent of Si3N4 was dispersed: Hardness HvE100, Sample B (comparative sample): Sliding member in which sample A was heat-treated at 380°C for 1 hour; Hardness Hv850, Sample C (this invention): In the plating solution Hs P O2 as phosphorus additive 3g/
liter, average particle size as large particles of dispersed particles 0.7μ
25 g/liter (3 volume percent) of Si3N4 and 5isN4 with an average particle size of 0°3 pm as small particles.
100g/liter (12% by volume) of
The sliding surface obtained after plating has an average grain size of 0. 7 μm Si
3N4 with 3 area percent and an average particle size of 0.3 μm
Sliding member in which i3N4 was dispersed at 12 area percent and the total amount of dispersed large particles and small particles was 15 area percent: Hardness Hv750, Sample D (Product of the present application): Sliding material obtained by heat treating sample C at 380°C for 1 hour. Component: Hardness HvlOOO1 Sample E (this invention): 3 g/liter of TMAB as a boron additive in the plating solution, 25 g/liter (3 volume percent) of Si3N4 with an average particle size of 0.7 μm as large particles of the dispersed particles, and small particles. Si3N4 with an average particle size of 0°3 μm is
Si3N with an average particle size of 0.7 μm was added to the sliding surface obtained after plating.
4 to 3 area percent and average particle size 0. 3 μm Si
Sliding member in which 12 area percent of 3N4 was dispersed, and the total amount of dispersed large and small particles was 15 area percent: Hardness Hv800, Sample F (this invention): A sliding member obtained by heat-treating sample E at 300°C for 1 hour. ;Hv
1050, Sample G (this invention): 3 g/liter of H and PO2 as phosphorus additives in the plating solution, and an average particle size of 2, O, cz as large particles of dispersed particles.
m of BN at 25 g/liter (3 volume percent) and 10 m of Si3N4 with an average particle size of 0.3 μm as small particles.
0 g/liter (12 volume percent) was added, and after plating, the resulting sliding surface had an average particle size of 2. 3 0μm BN
Area percent and average particle size 0. 3μm Si3N,
Sliding member with 12 area percent dispersed with 15 area percent of the total amount of large and small particles dispersed: Hardness Hv700, Sample H (invention): Sliding member obtained by heat treating sample G at 380°C for 1 hour: Hardness Hv850° Abrasion resistance and opponent attack tests were conducted using an Amsler type abrasion tester by immersing approximately half of the rotating piece in oil, bringing it into contact with a stationary piece, and applying a load. The test conditions are as follows.

(Test conditions for abrasion resistance and partner attack test) Compatible material:
PO25 (HR898) Lubricating oil: 10W30 Oil temperature: Room temperature Friction speed: 0.89m/5ee (500r, p, m, ) Load: 60Kg Time: 20 hours Wear amount measurement: Wear amount ( μm).

The test results are shown in Figure 1. It can be seen that Samples C-H according to the present invention have better wear resistance and attack resistance than Comparative Samples A-B.

Furthermore, it can be seen that even among the sliding members according to the present invention, those subjected to heat treatment are better in both abrasion resistance and attack resistance than those not subjected to heat treatment.

(Seizure resistance test) A rotating disk type plane sliding friction and wear test was conducted under the following test conditions.

(Seize resistance test conditions) Compatible material: PO25 (Hpa98) Lubricating oil:
SAE#30 + white kerosene (50% each) Oil amount: 0.02 liters/min Oil temperature:
50℃ (temperature inside the tank) Friction speed: 3.75m/see (300rpm) Surface pressure: 25Kg/cm2 After running in for 20 minutes under test conditions, the supply of lubricating oil was stopped and the surface pressure was 30 kg / c rrl
The surface pressure is then increased by 1 Ok g/c rrf every 2 minutes, and the surface pressure at which scuffing occurs is defined as the limit surface pressure for scuffing.

Sample A, the same as that used in the wear resistance and opponent attack tests
-I used H.

The test results are shown in Figure 2. As is clear from FIG. 2, the seizure resistance of the sliding member according to the present invention is better than that of the comparative sample. Furthermore, as in the case of wear resistance and attack resistance, it can be seen that among the sliding members according to the present invention, the heat-treated samples are superior to the non-heat-treated samples.

In the above embodiment, the Ni composite plating layer according to the present invention is provided directly on the base material of the sliding member, but the present invention is not limited to this. A nitrided layer may be provided on the nitrided layer, and a Ni composite plating layer according to the present invention may be provided thereon.

[Effects] The sliding member according to the present invention contains a predetermined proportion of hard particles and solid lubricant particles on its sliding surface and has a Ni composite plating film with excellent wear resistance and seizure resistance. Good results can be obtained even when used in engines that use high-output, high-load engines.

Furthermore, because expensive small particles are mixed or combined with relatively inexpensive large particles, the amount of expensive small particles used can be reduced while maintaining excellent wear resistance and seizure resistance, resulting in lower product costs. It is also possible to reduce the

[Brief explanation of the drawing]

FIG. 1 is a graph showing the test results regarding the wear characteristics and aggressiveness of the sliding member according to the present invention, and FIG. 2 is a graph showing the test results regarding the seizure resistance of the sliding member according to the present invention. Patent applicant Nippon Piston Ring Co., Ltd. Agent Patent attorney Hiroshi Kitazawa (1 other person)

Claims (2)

[Claims] (1) Selected from hard particles made of metal nitrides, carbides, oxides, etc. with a particle size of 10 μm or less, and solid lubricant particles made of metal sulfides, borides, fluorides, etc. with a particle size of 10 μm or less. A sliding member having, at least on its sliding surface, a Ni composite alloy plating layer in which one or more particles dispersed therein are dispersed, the average grain size of which is dispersed in the Ni composite alloy plating layer 0.
The dispersion rate of particles of 5 to 10.0 μm is less than 5 area percent, and the average particle size dispersed in the Ni composite plating layer is 0.
．． The dispersion rate of particles less than 5 μm is the above average particle size of 0.5 to 1
A sliding member characterized in that the dispersion rate, including the dispersion rate of particles of 0.0 μm, is 2 to 30 area percent in total. (2) The sliding member according to claim 1, wherein the Ni composite alloy plating layer has a hardness of Hv800 or more.