JPH03180491A - Sliding member - Google Patents

Abstract

PURPOSE:To form a sliding surface having superior wear, seizing and corrosion resistances even at high temp. under high load by forming an Ni-B composite plating layer contg. dispersed fine particles of a hard material and a solid lubricant on the sliding surface of a sliding member. CONSTITUTION:An Ni-B composite plating layer contg. 0.1-10% B and 5-30vol.% dispersed fine particles of <=10mum particle size including hard fine particles of Si3N4, SiC, WC, Al2O3, ZrO2, Cr2O3, etc., and solid lubricative particles of a sulfide such as MoS2, a boron compd. such as trimethylamine boran, a self- lubricative synthetic resin, etc., is formed by electroplating on the sliding surface of a sliding member exposed to high temp. under high load, e.g. the piston ring of an internal-combustion engine. The wear and seizing resistances of the sliding surface are remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a sliding member having a composite nickel alloy plating layer formed on its surface.

[Prior Art] Sliding parts such as piston rings for internal combustion engines that are subjected to high heat and high load are often coated with hard chrome plating to improve wear resistance, but chrome plating requires a long time to process and is difficult to use. Furthermore, plating costs are high because a large amount of money is required to prevent pollution of plating waste liquid, and furthermore, when used in engines that use high-lead gasoline as fuel, there are problems with wear resistance, seizure resistance, corrosion resistance, etc. As a method to solve this problem, composite plating, in which hard particles such as nitrides, carbides, and oxides are dispersed in a nickel-phosphorus alloy matrix, was developed
No. 6-18080. With this known plating, by appropriately selecting the type, size, and amount of dispersed particles, it is possible to form a film with a certain degree of wear resistance, seizure resistance, and corrosion resistance. , used in sliding members such as piston rings.

[Problems to be Solved by the Invention] However, the above-mentioned composite plating film in which hard particles are dispersed in the Ni-Keirin alloy matrix tends to become brittle when subjected to high heat and high load, so it cannot be used under severe conditions. When used as a sliding member of an engine operating at high speed, wear resistance, seizure resistance, etc. were not necessarily satisfactory.

An object of the present invention is to solve the problems of composite plating and to provide a sliding member having a film formed on the sliding surface with excellent wear resistance, seizure resistance, and corrosion resistance.

[Means for Solving the Problems] In order to achieve the above object, the means adopted by the present invention is to apply a nickel alloy matrix containing 0.1 to 10% of poron to the sliding surface of a metal sliding member. A composite plating film is provided in which hard particles with a particle size of 10 pm or less and/or solid Y4 smooth particles with a particle size of 104 m or less are dispersed and co-deposited in a volume ratio of 5 to 30%.

[Function] Poron contained in the nickel alloy base has the effect of increasing the hardness of the film and improving wear resistance, seizure resistance, and corrosion resistance. The amount of Poron is preferably 0.1 to 10% by hair volume.The reason is that if the amount of Poron is less than 0.1%, the effect will be small, and if it exceeds 10%, the film will become brittle and the impact strength will decrease.
This is because adhesion also deteriorates.

Hard particles (e.g. S
i3 N4, S iC, WC, Ami203, ZrO2
, Cr203, etc.) and solid lubricant particles (e.g., sulfide, boride, self-lubricating synthetic resin, one or more types) are 0.3 to 10μ.
In addition, the amount of hard particles and/or solid lubricant particles to be dispersed is preferably 5 to 30% by volume.If the particle size of the hard particles is 0.3 μm or less or 5% by volume or less, wear resistance is reduced. The effect of improving sex is small, and 104
If the amount exceeds m or 30% by volume, the strength of the film will actually decrease and the wear of the mating material will increase.

[Example] Examples of the sliding member of the present invention will be described.

(Composite plating conditions and liquid composition) (1) Plating condition temperature 55℃ PH3,5 Current density 5A/drn' (2) Comparative example of plating solution composition-1 Nickel sulfate 240g/nickel exchange chloride 45g/boric acid 30g/mon Silicon nitride (Si3N4. Average particle size 0.7 m) 100 g/text Comparative Example-2 Added 3.0% hypophosphorous acid to the plating solution composition of Comparative Example-1.
Example (invention product 1) Addition of 6°0 g/l of trimethylamine poran (hereinafter referred to as TMAB) to the plating solution composition of comparative example-l (invention product 2) Nickel sulfate 240g/invention nickel chloride 45 g/ml boric acid 30 g 1 boron cross-nitride 100 g/ml (BN, average particle size 2 m) TMAB 6, Og/l (inventive product 3) 6.0 g TMAB was added to the plating solution composition of Comparative Example-1. /text, 100 g/fL of molybdenum disulfide (MoS2, average particle size 0.1 μm) was added Under the above plating conditions, Comparative Example-1, Comparative Example-2, Implementation M (Invented product 1. Uninvented product) Composite plating films were formed for each of the liquid compositions of product 2 and product 3). When TMAR is added to Comparative Example-1, the hardness increases even if boric acid is not included in the liquid composition, but when considering the lifespan and stability of the liquid, it is better to add boric acid.

[Hardness test] The hardness of the composite plating films obtained using the three types of plating solutions was measured using a micro-Vickers hardness meter for the as-plated film and the film after heat treatment at a predetermined temperature for 1 hour. As shown in the figure.

From the above results, in the case of no addition of poron (Comparative Examples -1, -2)
) has low hardness as plated, and furthermore, a large decrease in hardness occurs at a heat treatment temperature of 300°C. In comparison, the product of the present invention (Example) containing poron already exhibits high hardness as plated, and the heat treatment temperature is 300.
It can be seen that the addition of poron also contributes to improving heat resistance since it maintains high hardness up to around 350°C.

Further, as in Comparative Example-2, the phosphorus-added film is more effective in improving hardness than the non-additive film (Comparative Example-1). C'b)
Comparing the phosphorus-added coating and the poron-added coating of the example of the present invention (product of the present invention), the boron-added coating has higher hardness even as plated, and is more suitable as a sliding member. In addition, when applying a phosphorus-added coating to a harsh sliding member, it cannot be used unless it is heat-treated at 350 to 380°C, but the poron-added coating of the present invention has high hardness from the beginning and cannot be used after heat treatment. is not necessary, or even if it is, the temperature may be lower than 300°C, which reduces the cost accordingly.

[Abrasion Test] The abrasion resistance of Comparative Example-1, Comparative Example-2, and the product of the present invention (Example) was evaluated under the abrasion test conditions shown in Table 1. For the abrasion resistance test, an Amsler type abrasion tester was used, and test pieces (18
mmX l 2mmX6mm) as the fixed piece, and the mating material (
The rotating piece) has a donut shape (outer diameter 40 mm, inner diameter 16 m).
m, thickness 10 mm) was used. It was set so that the formed plating film was in contact with the doughnut-shaped test piece. The test results are shown in Figure 2.

(Scuffing test Vk) The scuffing resistance of Comparative Example-1, Comparative Example-2, and the product of the present invention (Example) was evaluated under the scuffing test conditions shown in Table 2. The test results are shown in FIG.

As is clear from Fig. 3, N1-B-S of the product of the present invention
i3N4 is conventional comparative example-1 (Ni-Si3N4),
Scuffing resistance is improved compared to Comparative Example 2 (Ni-P-Si3 N4).

Table 1: Wear test conditions: Table 2: Scuffing test conditions [Effects of the invention] As described above, the sliding member of the present invention has a composite plating film provided on the sliding surface that is formed by combining hard particles and solids on a nickel-poron alloy base. Since it contains both or one of the lubricating particles dispersed therein, it has an excellent effect that it does not become brittle due to high heat and high load compared to conventional nickel-phosphorus alloy base materials. When the sliding member of the present invention is made by applying nickel-poron composite plating to the surface of cast iron or steel piston rings or cylinder litchi, etc., it has high wear resistance and scuffing resistance, so it is suitable for high temperature and high load engines. can also be used adequately.

[Brief explanation of drawings]

Fig. 1 is a graph showing the change in hardness due to heat treatment, Fig. 2 is a graph showing the results of the wear test, and Fig. 3 is a graph showing the results of the scuffing test.

Claims (1)

[Claims] 1) Eutectoid dispersion of 5 to 30% by volume of hard particles with a particle size of 10 μm or less and/or solid lubricant particles with a particle size of 10 μm or less in a nickel alloy base containing 0.1 to 10% boron. A sliding member characterized in that a composite plating film is formed on the sliding surface.