JP2002146598A - Composite plating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that, when the conventional composite plating film obtained by dispersing a ceramic based dispersion material into nickel- phosphorous plating is slid with a corresponding member coated with a hard film such as a chromium plated layer under a high load, a relative amount of wear is caused, and that, in a film with hard particles dispersed, the coefficient of friction in sliding increases. SOLUTION: This composite plating film is deposited on the surface of a base material consisting of a light alloy. The film contains a matrix consisting of a nickel-phosphorous alloy and boron carbide particles or/and zirconia (zirconium oxide) particles dispersed into the matrix. In this way, its wear resistance, durability or seizure resistance are improved while maintaining the lubricity equal to that of the conventional composite plating film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite plating film applied to a sliding member such as an inner surface of an engine cylinder having excellent wear resistance, durability or seizure resistance.

[0002]

2. Description of the Related Art Conventionally, cast iron has been used for cylinders of various engines. However, in recent years, in motorcycles, small generator engines, lawn mower engines, and the like, there has been an increasing demand for weight reduction for energy saving, and light alloys have been increasingly used for engine cylinders. However, in the case of a light alloy cylinder, hard chromium plating or nickel-phosphorus plating is mainly performed.

In recent years, composite plating with improved wear resistance has been frequently performed by dispersing ceramic particles as a dispersing material in a nickel-phosphorus alloy plating film. The dispersion material has an effect of relaxing stress in the film and increasing the hardness of the entire film. In addition, silicon carbide is generally used as the dispersing material because of its ease of handling and difficulty in producing defects in the film quality.

[0004] Composite plating in which ceramic particles are dispersed in a nickel-phosphorus alloy plating film has been applied to a piston for an internal combustion engine disclosed in JP-A-55-78856 and to a SiC composite plating disclosed in JP-A-5-171455. It has been disclosed. Further, a composite plating in which silicon carbide or silicon nitride is dispersed in nickel-phosphorus plating is used for the wear-resistant metal member disclosed in JP-A-5-78900, in combination with the sliding member disclosed in JP-A-9-42447. Discloses a composite plating film in which one of boron nitride, silicon carbide and silicon nitride is used as a dispersing material during nickel-phosphorus plating.

[0005]

However, the composite plating film obtained by dispersing the above-mentioned ceramic dispersing material in nickel-phosphorus plating has a high load under the high load with the mating member hard coated with a chromium plating layer or the like. A significant amount of wear occurs when slid. Further, in a coating film in which hard particles are dispersed, the friction coefficient at the time of sliding tends to increase.

[0006]

According to a first aspect of the present invention, there is provided a matrix formed of a nickel-phosphorus alloy and formed on a surface of a substrate made of a light alloy. The composite plating film is characterized in that either boron carbide particles or zirconia (zirconium oxide) particles, or both particles are dispersed and contained.

According to a second aspect of the present invention, there is provided a composite plating film characterized in that a matrix made of a nickel-phosphorus alloy contains 1 to 5% of a phosphorus compound. Also,
In claim 3, the boron carbide particles dispersed in the matrix disperse 1 to 2 micron particles by 2 to 8% by volume, and in claim 4, the zirconia particles dispersed in the matrix are 1 to 2 micron Are dispersed in a volume of 2 to 8% by volume to form a composite plating film.
According to a fifth aspect of the present invention, the boron carbide particles and the zirconia particles dispersed in the matrix form a composite plating film in which 1 to 2 micron particles are dispersed by 2 to 8% by volume in total.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a longitudinal sectional view of a composite plating film showing a first embodiment of the present invention. In the figure, a plating solution is formed on the surface of a base material 1 made of a light alloy, and a plating solution containing nickel sulfate, nickel chloride and a phosphorus compound (phosphonic acid) is used. The nickel-phosphorus composite plating film 2 containing the dispersing material 4 in the matrix 3 made of a nickel-phosphorus alloy can be formed by mixing the particulate dispersing material and performing electroplating while stirring. When abrasion resistance and durability are required, the dispersion material 4 is made of boron carbide particles,
When abrasion resistance and seizure resistance are required, zirconia particles are used.

In the second embodiment, the matrix 3 made of nickel-phosphorus contains 1 to 5% of a phosphorus compound. The purpose of adding the phosphorus compound is to increase the hardness by using a nickel-phosphorus alloy. Generally, as the amount of phosphorus increases, the hardness of the base material 1 made of a light alloy becomes harder. However, when the amount of phosphorus is excessive, the composite plating film 2 becomes too hard and brittle, and on the contrary, the durability decreases. Therefore, the content of phosphorus in the coating is desirably 1 to 5%,
By containing phosphorus in this range, a composite plating film 2 having both required hardness and toughness can be obtained.

[0010] In the third embodiment, the boron carbide particles dispersed in the matrix 3 are particles of 1 to 2 microns dispersed in 2 to 8% by volume. If the particle size of the dispersion material 4 is excessively large, the particles are likely to precipitate, and the dispersion in the film becomes insufficient. Conversely, if the particle size is too small, the particles tend to segregate in the film, and a uniform coating cannot be obtained. For this reason, the particle size of the dispersion material 4 is optimally 1 to 2 microns.
Regarding the amount of the dispersing material 4, dispersing the particles in the coating has the effect of increasing the hardness and reducing the residual stress, and has the effect of improving the abrasion resistance. The material itself becomes brittle, and the wear resistance is rather reduced. For this reason, the optimal amount of the dispersant 4 is 2 to 8% by volume.

In the fourth embodiment, the zirconia particles dispersed in the matrix 3 are particles of 1 to 2 microns dispersed in 2 to 8% by volume. If the particle size of the dispersion material 4 is excessively large, the particles are likely to precipitate, and the dispersion in the film becomes insufficient. Conversely, if the particle size is too small, the particles tend to segregate in the film, and a uniform coating cannot be obtained. For this reason, the particle size of the dispersion material 4 is optimally 1 to 2 microns.
Regarding the amount of the dispersing material 4, dispersing the particles in the coating has the effect of increasing the hardness and reducing the residual stress, and has the effect of improving the abrasion resistance. The material itself becomes brittle, and the wear resistance is rather reduced. For this reason, the optimal amount of the dispersant 4 is 2 to 8% by volume.

In the fifth embodiment, the boron carbide particles and the zirconia particles dispersed in the matrix 3 are particles of 1 to 2 microns. The total amount of boron carbide particles and zirconia particles dispersed in the matrix 3 is 2 to 8% by volume. If the particle size of the dispersion material 4 is excessively large, the particles are likely to precipitate, and the dispersion in the film becomes insufficient. Conversely, if the particle size is too small, the particles tend to segregate in the film, and a uniform coating cannot be obtained. For this reason, the particle size of the dispersion material 4 is optimally 1 to 2 microns. Regarding the amount of the dispersing material 4, dispersing the particles in the coating has the effect of increasing the hardness and reducing the residual stress, and has the effect of improving the abrasion resistance. The material itself becomes brittle, and the wear resistance is rather reduced. Therefore, the amount of the dispersant 4 is 2 to 8% by volume.
Is optimal.

[0013]

The composite plating film according to the present invention will be described in more detail with reference to the following examples. Example 1 (Wear test) Two disk-shaped test pieces 5 were manufactured using an aluminum alloy (AC4B), and a composite plating film 2 was applied to the surface portions thereof. Next, the surface was ground to perform a wear test. The composite plating film thickness after grinding is about 50 microns. Test piece A is a composite plating film in which 3.2% by volume of boron carbide particles according to the present invention are dispersed. Test piece B is a composite plating in which conventional silicon carbide particles are dispersed in 5.1% by volume as a comparative example. It is a coating.

The wear of the test piece 5 was measured using a pin-disk type wear tester as shown in FIG.
The pins 6 on the sliding surface are made of hardened steel plated with hard chrome. The test piece 5 and the pin 6 are
Then, a load of 20 kgf was applied by the load applying device 8 and the test piece 5 was rotated by the rotation driving device 9 to measure the wear resistance and the friction coefficient. Table 1 shows the test conditions.

[0015]

[Table 1]

FIG. 3 is a diagram comparing the wear resistance of the composite plating films. The horizontal axis indicates the test piece A according to the present invention and the test piece B of the comparative example, and the vertical axis indicates the wear depth (μm). ing. As is apparent from the figure, the wear depth of the composite plating film of the present invention A (in which boron carbide was used as a dispersing material) was 1.84 μm, and that of the composite in Comparative Example B (in which silicon carbide was used as a dispersing material). The wear depth of the plating film is 4.67μ
m, the present invention A has a smaller wear depth than the comparative example B, and shows excellent wear resistance.

FIG. 4 is a diagram comparing the friction coefficients of the composite plating films, wherein the horizontal axis represents the test piece A according to the present invention and the test piece B of the comparative example, and the vertical axis represents the average friction coefficient. The average friction coefficient is an average value of the friction coefficient measured every second. As is apparent from the figure, the average wear coefficient of the composite plating film of the present invention A (using boron carbide as a dispersing material) was 0.089, and the composite plating using Comparative Example B (using silicon carbide as a dispersing material). The average wear coefficient of the coating is 0.088, and the composite plating coating according to the present invention A,
The average wear coefficient of the composite plating film according to Comparative Example B was almost the same as that of the composite plating film, indicating that they had the same lubricity.

The use of boron carbide as the dispersing material 4 of the composite plating film 2 resulted in good results because it has almost the same hardness as silicon carbide and a small specific gravity, so that This seems to be related to the fact that it is easy to disperse in heat and that heat generated locally during sliding is easily dissipated due to good thermal conductivity.

Example 2 Two disk-shaped test pieces were manufactured using an aluminum alloy (AC4B), and a composite plating film was applied to the surface of these test pieces. Next, the surface was ground to perform a scuffing test and a wear test. The composite plating film thickness after grinding is about 50 microns. Test piece C is a composite plating film in which zirconia particles according to the present invention are dispersed by 4.8% by volume, and test piece D is a comparative example in which conventional silicon carbide particles are dispersed by 5.1% by volume. It is.
The test conditions are the same as those in Table 1.

(Scuffing test) The scuffing test was carried out by a known method.
The test was performed at the surface pressure at the time of seizure. FIG. 5 shows the results of the scuffing test, in which the horizontal axis represents the test piece C according to the present invention.
(With zirconia as the dispersing material) and the test piece D of the comparative example
The vertical axis represents the surface pressure (kgf / cm ² ) during seizure. As is apparent from the figure, the surface pressure during seizure of the composite plating film of the present invention C was 390, the surface pressure during seizure of the composite plating film of Comparative Example D was 320, and the composite pressure of the present invention C was This shows that the plating film has better seizure resistance than the composite plating film of Comparative Example D.

(Wear Test) A wear test was performed using a pin-disk type wear tester as shown in FIG. The test conditions are the same as those in Table 1 above. FIG. 6 is a diagram comparing the wear depths of the composite plating films. The horizontal axis represents the test piece C according to the present invention and the test piece D of the comparative example.
And the vertical axis indicates the friction depth (μm). As is apparent from the figure, the wear depth of the composite plating film of the present invention C (in which zirconia was used as a dispersing material) was 4.75.
μm, the wear depth of the composite plating film of Comparative Example D (in which silicon carbide was used as the dispersing material) was 4.25 μm,
The friction depths of the composite plating film of the present invention C and the composite plating film of Comparative Example D were almost the same, indicating that they had the same lubricity.

[0022]

According to the present invention, there is provided a matrix formed of a nickel-phosphorus alloy containing 1 to 5% of a phosphorus compound and formed on the surface of a substrate made of a light alloy. 2 to 8% by volume of zirconium oxide particles having a particle size of 1 to 2
Micron boron carbide particles were dispersed in 2-8% by volume.
This makes it possible to improve abrasion resistance and seizure resistance while maintaining the same lubricity as a conventional composite plating film using silicon carbide as a dispersing material.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a composite plating film according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a pin-disk type wear tester used for a wear test of the present invention.

FIG. 3 is a diagram comparing the wear resistance of a composite plating film according to a second embodiment of the present invention and a conventional example.

FIG. 4 is a diagram comparing the coefficient of friction of the composite plating film of the second embodiment of the present invention with that of the conventional composite plating film.

FIG. 5 is a diagram comparing the surface pressure of the composite plating film of the third embodiment of the present invention with that of the conventional example during seizure.

FIG. 6 is a diagram comparing the wear depths of the third embodiment of the present invention and the composite plating film of the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Composite plating film 3 Matrix 4 Dispersion material 5 Test piece 6 Pin 7 Lubricating oil 8 Load applying device 9 Rotation drive device

Claims (5)

[Claims] 1. A matrix formed of a nickel-phosphorus alloy formed on a surface portion of a substrate made of a light alloy, and boron carbide particles and / or dispersed in the matrix.
And a zirconia particle. 2. The composite plating film according to claim 1, wherein the matrix composed of a nickel-phosphorus alloy contains 1 to 5% of a phosphorus compound. 3. The composite plating film according to claim 1, wherein the boron carbide particles dispersed in the matrix have particles of 1 to 2 microns dispersed therein in an amount of 2 to 8% by volume. 4. The composite plating film according to claim 1, wherein the zirconia particles dispersed in the matrix have particles of 1 to 2 microns dispersed therein in an amount of 2 to 8% by volume. 5. The boron carbide particles and zirconia particles dispersed in the matrix, wherein 1 to 2 micron particles are dispersed by 2 to 8% by volume in total. Composite plating film.