JP2914746B2 - Sliding member - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sliding member in which a Ni composite alloy plating layer in which hard particles are dispersed is formed on a sliding surface.

[Prior Art] A sliding member such as a piston ring for an internal combustion engine subjected to a high temperature and a high load is often provided with hard chrome plating on a sliding surface in order to enhance abrasion resistance. However, chromium plating not only requires a long time for its treatment, but also has a problem that a large amount of cost is required for treating a plating waste solution to prevent environmental pollution, and as a result, the cost required for plating is increased. Also, using chrome-plated sliding members for components of engines that use high-lead gasoline or high-output, high-load engines can cause problems in terms of wear resistance, corrosion resistance, seizure resistance, etc. there were.

As a method for solving this problem, a composite plating in which hard particles such as nitrides, carbides and oxides are dispersed in a Ni-P alloy matrix has been proposed in Japanese Patent Publication No. 56-18080. According to this known plating, the type and particle size of the dispersed particles,
By selecting an appropriate amount of dispersion, abrasion resistance to some extent,
It can form a film having excellent seizure resistance and corrosion resistance, and has already been used for sliding members such as cylinder liners and piston rings.

In order to further reduce friction, in addition to the hard particles,
Plating with the addition of solid lubricant particles has also been used.

Usually, the particles dispersed in the plating layer as described above have an average particle diameter of 0.5 to 10.0 μm.

[Problems to be Solved by the Invention] In the Ni composite plating layer in which the hard particles are dispersed
The Ni-P alloy matrix tends to become brittle under the influence of high heat and high load, and when used as a sliding member of an engine that is operated at high speed under severe conditions, its wear resistance and seizure resistance are always satisfactory It was not something.

Further, the hard particles and the like in the Ni composite plating layer improve the wear resistance and seizure resistance of the plating layer by coming into contact with the mating material during sliding. Therefore, when the number of particles such as hard particles and solid lubricating particles dispersed in the Ni composite plating layer is increased, the dispersion area of the particles increases accordingly, and the wear resistance and seizure resistance of the plating layer are improved. Become.

However, when the dispersion ratio of these particles becomes a certain value or more, the ratio of the base material in the plating layer decreases, and the holding power of the plating layer for retaining the particles and the like decreases. For this reason, the particles easily fall off from the plating layer, so that the plating layer becomes brittle, and as a result, abrasion resistance and seizure resistance decrease. Therefore, abrasion resistance by increasing the dispersion of the particles,
There was a certain limit in improving seizure resistance.

On the other hand, if fine particles are used, the dispersion ratio (area percent) of the particles to the plating layer is not significantly increased,
The particle dispersion area can be increased, and as a result, the wear resistance can be improved without increasing the brittleness of the plating layer. However, there is a problem that fine particles are expensive and products using the same increase the cost.

In view of the above problems, the present invention improves the wear resistance and seizure resistance of a plating layer by dispersing two types of hard particles having different average particle sizes in a predetermined ratio in the plating layer on the sliding surface. It is an object of the present invention to provide a sliding member having a plating film as intended and having a low product cost.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a hard particle having a particle diameter of 10 μm or less and a metal sulfide, boride or fluoride comprising a metal nitride, carbide or oxide. A sliding member having a Ni composite alloy plating layer on one or more sliding surfaces of which one or two or more particles selected from solid lubricating particles having a particle size of 10 μm or less are dispersed.
In the composite alloy plating layer, at least one of large hard particles or solid lubricating particles having an average particle size of 0.5 to 10.0 μm and small hard particles or solid lubricating particles having an average particle size of less than 0.5 μm. Is dispersed together with at least one of the above, the dispersion ratio of the large particles is less than 5 area percent, and the dispersion ratio of the small particles is 2 to 30 in total with the dispersion ratio of the large particles. The present invention provides a sliding member having a dispersion ratio that is an area percentage.

[Operation] In the sliding member according to the present invention, the ratio of particles having an average particle diameter of 0.5 to 10.0 μm and particles having an average particle diameter of less than 0.5 μm contained in the Ni composite alloy plating on the sliding surface is within a predetermined range. Therefore, the abrasion resistance and seizure resistance of the sliding surface are excellent. 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.

EXAMPLES Hereinafter, the 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 a base material of the sliding member of the present invention, for example,
A steel material containing 0.16 to 1.30% of carbon and 12 to 19% of chromium, or a steel material containing molybdenum and vanadium therein can be cited as an example of use.

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

Here, examples of the hard particles and the solid lubricant particles include the following. Hard particles include Si ₃ N ₄ , SiC,
Metal nitrides, metal carbides such as WC, Al ₂ O ₄ , ZrO ₂ , Cr ₂ O ₃ ,
Metal oxide particles and the like; solid lubricant particles such as MoS ₂ (molybdenum disulfide), BN (boron nitride), and metal sulfides such as polytetrafluoroethylene;
Boride or fluoride.

Further, the average particle size in the Ni composite alloy plating layer is 0.5 to 1
The flow particles (small particles) having a particle size of less than 5% by area with respect to the plating layer and having an average particle size smaller than 0.5 μm are smaller than the particles having been used conventionally. The particles are dispersed so as to have a ratio of 2 to 30 area percent in the plating layer in total with the large particles having a diameter of 0.5 to 10.0 μm.

Here, the reason why the dispersion ratio of the large particles is set to less than 5 area percent is that if the dispersion ratio is higher than this, the effect of dispersing the small particles together does not occur, and the same as the case where only the large particles are dispersed. This is because only the effect occurs.

The reason why the total dispersion ratio of the large particles and the small particles is set to 30 area percent or less is to prevent the Ni composite alloy plating layer from becoming brittle, and to set the area ratio to 2 area percent or more, these particles are used below. This is because the dispersed effect does not occur.

If the particle size of the particles to be dispersed is 10 μm or more, the aggressiveness to the opponent becomes strong, and the particles fall off, thereby impairing the wear resistance of the plating film.

The dispersion amount of the hard particles or solid lubricant particles is appropriately selected in consideration of the purpose and the like within the above range.

Further, when the plating film in which the hard particles and the solid lubricant particles are dispersed is subjected to a heat treatment, the hardness can be increased and the toughness can be enhanced. Since the rate of increase in hardness depends on the processing temperature,
By appropriately selecting the treatment temperature, the hardness of the Ni composite alloy plating layer can be changed within a certain range, and a hardness suitable for use conditions can be obtained.

The thickness of the Ni composite alloy plating layer of the present invention is 5 μm to 250 μm.
m, and the thickness is selected according to the material of the outer peripheral sliding surface of the sliding member, surface treatment, and the like.

An example of a plating layer and plating conditions for manufacturing the sliding member according to the present invention will be described below.

Plating solution composition and plating conditions nickel sulfate _{(NiSO 4 · 6H 2 O)} : 240g / l nickel chloride _{(NiCl 2 · 6H 2 O)} : 45g / l boric acid _{(H 3 BO 3): 30g} / l Current density: 5A / dm ² solution temperature: 55 ± 1 ° C. In the above table, hypophosphorous acid (H ₃ PO ₂ ) was used as a phosphorus additive in a Watt bath as an electrolytic Ni plating bath, and trimethylamine borane was used as a boron additive. (CH ₃ ) ₃ NB
H _3: Using the TMAB.

Next, test results on the abrasion resistance, counterpart aggression, and seizure resistance of the sliding member according to the present invention will be described.

(Abrasion resistance and mating aggression test) The following were used as test samples.

Sample A (comparative sample): 3 g / liter of H ₃ PO ₂ as a phosphorus additive in the plating solution,
125 g / liter (15 volume percent) of Si ₃ N ₄ having an average particle diameter of 1.0 μm is added as dispersed particles, and 15 area percent of Si ₃ N ₄ having an average particle diameter of 1.0 μm is dispersed on a sliding surface obtained after plating. Sliding member subjected to hardness: hardness Hv600, sample B (comparative sample): sliding member obtained by heat-treating sample A at 380 ° C. for 1 hour; hardness H
v850, Sample C (invention of the present invention): 3 g / liter of H ₃ PO ₂ as a phosphorus additive in the plating solution,
Si ₃ N ₄ having an average particle size of 0.7 μm
g / liter (3% by volume) and 100 g / liter (12% by volume) of Si ₃ N ₄ having an average particle size of 0.3 μm as small particles were added to the sliding surface obtained after plating.
μm Si ₃ N ₄ with 3 area percent and average particle size 0.3 μm
A sliding member in which Si ₃ N ₄ is dispersed by 12 area percent and the total amount of dispersion of large particles and small particles is 15 area percent: hardness Hv750, sample D (product of the present application): sample C is heat-treated at 380 ° C. for 1 hour. Sliding member; hardness H
v1000, Sample E (present invention): 3 g / liter of TMAB the plating solution as a boron additive, the average particle size of 0.7μm as large particles of the dispersed particles Si ₃ N ₄
Was added at 25 g / liter (3 volume percent) and 100 g / liter (12 volume percent) of Si ₃ N ₄ having a small particle diameter of 0.3 μm and an average particle diameter of 0.7 μm was added to the sliding surface obtained after plating. 3% by volume of Si ₃ N ₄ and an average particle size of 0.3
A sliding member in which Si ₃ N ₄ of 12 μm was dispersed by 12 area percent and the total amount of dispersion of large particles and small particles was 15 area percent: hardness Hv800, sample F (invention of the present application): sample E at 300 ° C. for 1 hour Heat treated sliding member; Hv105
0, Sample G (invention of the present application): 3 g / liter of H ₃ PO ₂ as a phosphorus additive in the plating solution,
25 g of BN with an average particle size of 2.0 μm as large particles of dispersed particles
Liter (3% by volume) and 100 g / liter (12% by volume) of Si ₃ N ₄ having an average particle diameter of 0.3 μm as small particles are added to the sliding surface obtained after plating to obtain an average particle diameter of 2.0 μm.
Si 3 area percent and the average particle size 0.3μm to BN of m ₃ N ₄
12% by area and a total of 15 area percent of the dispersion amount of the large particles and the small particles is a sliding member: hardness Hv70
0, Sample H (invention of the present invention): sliding member obtained by heat-treating sample G at 380 ° C. for 1 hour; hardness H
v850.

The abrasion resistance and aggressiveness tests were performed by using an Amsler abrasion tester by immersing almost half of the rotating piece in oil, contacting the fixed piece and applying a load. The test conditions are as follows. (Test conditions for abrasion resistance and mating aggression test) Mating material: FC25 (H _RB 98) Lubricating oil: 10W30 Oil temperature: Room temperature Wear speed: 0.89m / sec (500r.pm) Load: 60Kg Time: 20 hours wear Amount measurement: The wear amount (μm) was measured by a step profile using a roughness meter.

The test results are as shown in FIG. It can be seen that Samples C to H according to the present invention have better abrasion resistance and aggressiveness to the other party than Comparative Samples A and B. In addition, it can be seen that even the sliding member according to the present invention, which has been subjected to the heat treatment, has better abrasion resistance and counterpart aggressiveness than the sample which has not been subjected to the heat treatment, as compared with the sample which has not been subjected to the heat treatment.

(Seizure Resistance Test) A rotating disk type flat sliding friction wear test was performed under the following test conditions.

(Seizure resistance test conditions) Partner material: FC25 (H _RB 98) Lubricating oil: SAE # 30 + white kerosene (50% each) Oil volume: 0.02 l / min Oil temperature: 50 ° C (tank temperature) Friction speed: 3.75 m / sec (300rpm) surface pressure: after the operation to if 25 Kg / cm ² or more test conditions at 20 minutes, stop the supply of the lubricating oil, the surface pressure from the surface pressure 30kg / cm ² every 2 minutes Ten
Pressure is applied in units of kg / cm ² , and the surface pressure at which scuffing occurs due to this is defined as the scuffing occurrence limit surface pressure.

The same samples A to H as those used for the abrasion resistance and the aggressiveness test were used.

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

In the above embodiment, the Ni composite alloy 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, And a Ni composite alloy plating layer according to the present invention may be provided thereon.

[Effect] The sliding member according to the present invention contains a predetermined ratio of hard particles and solid lubricating particles on its sliding surface, and has a Ni composite alloy plating film having excellent wear resistance and seizure resistance. Even if the present invention is used for an engine using a high-power or high-load engine, good results can be obtained.

Furthermore, since expensive small particles are mixed or used in combination with relatively inexpensive large particles, the amount of expensive small particles used can be suppressed while maintaining excellent abrasion resistance and seizure resistance. Can be downed.

[Brief description of the drawings]

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.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16J 1/00-10/04 C23C 24/00-30/00

Claims (2)

(57) [Claims] (1) Hard particles of a metal nitride, carbide or oxide having a particle size of 10 μm or less and solid lubricating particles of a metal sulfide, boride or fluoride having a particle size of 10 μm or less. A sliding member having, on at least a sliding surface thereof, a Ni composite alloy plating layer in which one or more particles are dispersed, wherein the Ni composite alloy plating layer has an average particle size of 0.5 to 10.0 μm.
m, at least one of large hard particles or solid lubricating particles, and at least one of small hard particles or solid lubricating particles having an average particle size of less than 0.5 μm are coexistent and dispersed, The dispersion rate of the large particles is less than 5 area percent, and the dispersion rate of the small particles is 2 to 30 area percent in total with the dispersion rate of the large particles. Sliding member. 2. The sliding member according to claim 1, wherein the hardness of the Ni composite alloy plating layer is Hv800 or more.