JPH0121879B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a sliding member with excellent wear resistance and seizure resistance, particularly a wear resistant material suitable for vane materials such as piston rings and cylinders of internal combustion engines, rotary pumps, and rotary compressors. This invention relates to composite nickel-phosphorus alloy plating, which is a coating with excellent seizure resistance. [Prior Art] Conventionally, parts that require wear resistance and seizure resistance, such as sliding members such as piston rings and cylinders of internal combustion engines, have been treated with hard chrome plating, thermal spraying, etc. to impart wear and seizure resistance. surface treatments are used. However, if we take piston rings as an example,
Hard chrome plating is becoming unable to cope with the deterioration of sliding conditions due to higher speeds and higher output engines, and thermal spraying has its own excellent wear and seizure resistance, but Cylinder wear tends to increase, so it has not become widely used. In addition, recently, as a countermeasure against the use of high-lead gasoline, composite nickel-phosphorus alloy plating with silicon nitride dispersed has been proposed as a surface treatment other than hard chrome plating and thermal spraying (Japanese Patent Laid-Open Publication No. 59-96295). ). However, in the case of a composite nickel-phosphorus alloy in which silicon nitride is dispersed, although it has the effect of reducing the wear of the mating material and improving the seizure resistance, the problem of its own wear resistance has not been completely resolved. [Problems to be Solved by the Invention] Under these circumstances, it is desired to establish a surface treatment technology that can improve its own wear resistance and seizure resistance and also reduce wear on the mating material. In order to meet the above-mentioned needs, the present invention has been made in order to not only improve the wear resistance and seizure resistance of the material itself, but also reduce the wear of the mating material. [Means to solve the problem] Particle size of 5 μm or more in the nickel-phosphorus alloy plating layer
Silicon nitride with a particle size of 1 μm or more and titanium carbide with a particle size of 1 μm or more and 3 μm or less is combined in a volume ratio of 20:80 to 80:20, and the total of the silicon nitride and the titanium carbide is 20:80 to 80:20 by volume. It is characterized by being dispersed and precipitated at 5 to 30 Vol% with respect to the above-mentioned nickel-phosphorus alloy plating layer, thereby improving its own wear resistance and seizure resistance compared to the previously proposed silicon nitride alone dispersed precipitation. In addition to making it equal to or better than the case of
Abrasion of the mating material can be greatly reduced. In the present invention, the reason why silicon nitride and titanium carbide are dispersed and precipitated in the nickel-phosphorus alloy plating layer (hereinafter referred to as Ni-P plating) is as follows. That is, as shown in the wear test results (Fig. 3) using a reciprocating friction tester shown schematically in Fig. 1, Ni
-SiC as a composite material to be dispersed during P plating,
As a result of conducting wear tests using hard particles of TiC, Si ₃ N ₄ , and Cr ₃ C ₂ as candidates (hereinafter referred to as Experiment 1), the results showed that in the case of a gray cast iron (FC25) counterpart equivalent to a cylinder,
When the above-mentioned hard particles were dispersed alone in Ni-P plating, there was a tendency that those with excellent wear resistance on their own would have more wear on the other side, and those with less wear on the other side would have poorer wear resistance on their own. , it is not possible to obtain something that can satisfy both parties. On the other hand, when a material is combined with a material that has excellent wear resistance and a material that has low wear resistance, the weak points of both materials tend to be compensated for. In particular, the combination of Si ₃ N ₄ and TiC is
Compared to when dispersed during Ni-P plating, both wear on itself and wear on the other party are reduced, and a remarkable synergistic effect can be obtained. Therefore, in the present invention, silicon nitride and titanium carbide are dispersed and precipitated. In Figure 1, 1 is the pin (upper specimen), 2 is the flat plate (lower specimen ((mate material))), 3 is the hydraulic cylinder, 4 is the load cell, 5 is the drive source, and arrow α is the sliding Show direction. To evaluate the amount of wear, the wear mark of the pin (upper specimen) 1 shown in Figure 2A is measured at two locations using a roughness meter running in the direction of arrow β, and the average value is displayed. Flat plate shown in B (lower specimen ((opposite material))) 2
For this, the height difference was measured at three locations using a roughness gauge running in the direction of the arrow γ, and the average value is shown. The test conditions for Experiment 1 are as follows. 1 Test specimen Lower specimen (counterpart material) (2 in Figure 1) FC25 (JIS G5501 (1976) gray cast iron): Hardness HRB96 70 ^L × 17 ^w × 7 ^t (mm) flat plate test surface Buffing. Surface roughness: 0.4μm Upper specimen (1 in Figure 1) Base material: SK5 (JIS G4401 (1972) carbon tool steel) Hardness HRB98 Shape: 8〓× ^23L (mm) end face with ^18R Spherical processing Plating: Hard particles are dispersed on the end surface to coat Ni-
P-plating was applied to a thickness of 0.18mm, giving it a ^18R spherical finish. The plating conditions at that time were as follows. Bath composition: Nickel sulfamate: 400g/Boric acid: 60g/Sodium hypophosphite: 2g/Pitt inhibitor (sodium lauryl sulfate):
2ml/ Bath temperature: 53℃ Bath PH: 4.0 Current density: 6A/dm ² , time: 3.5Hr Composite material (fine particles): 80g/, SiC, TiC,
Si ₃ N ₄ , Cr ₃ C ₂ , SiC + Si ₃ N ₄ (50:50), SiC
+Cr ₃ C ₂ (50:50), TiC + Si ₃ N ₄ (50:50),
TiC+ _Cr3C2 ( _50:50 )

【table】

[Table] Note 1. Load 2 of the pyramid indenter of the Micro-Vickers hardness tester Wear test conditions Breaking in: 2Kgf x 100cm/min (hereinafter abbreviated as cpm) x 30 minutes Test: 10Kgf x 600cpm x 30 minutes Lubricating oil: SAE10W equivalent, 0.2cc/min Mist spraying Figure 4 shows the relationship between the amount of P precipitation during Ni-P plating and the hardness (average value), and the results of a reciprocating wear test (hereinafter referred to as Experiment 2) with varying hardness. is shown in Figure 5. The shape and finish of the wear test piece was determined in Experiment 1.
is the same as Furthermore, the total composite ratio of silicon nitride and titanium carbide is
The reason for setting the Ni-P plating to 5 to 30 vol% is that as shown in the reciprocating friction test (hereinafter referred to as Experiment 3) results shown in Figure 6, less than 5 vol% causes sufficient wear on the Ni-P plating. However, if it exceeds 30 vol%, the plating film becomes hard and brittle, causing hard particles to fall off, which not only accelerates the wear of the other but also increases the wear of itself. In addition, considering the wear of itself and the other party, a range of 10 to 20 vol% is more desirable. The reason why the P content in the Ni-P plating is 1 to 8 wt% and the micro-Vickers hardness of the plating that has been subjected to hardening heat treatment is 800 or more is that Looking at the relationship between quantity and hardness, as shown in Figure 5, Hmv800
As shown in Figure 4, in order to significantly reduce the amount of wear and secure Hmv800 or more, as shown in Figure 4,
This is because P precipitation of 1wt% or more is required, and if P exceeds 8wt%, the hardness of the Ni-P alloy plating film increases, but it becomes brittle, so it is not suitable as a wear-resistant coating layer. be. Note that the upper limit of hardness can be about Hmv1100 by subjecting a plating layer with a P content of 8 wt% to hardening heat treatment. The hardening heat treatment conditions for Ni-P alloy plating above are as follows:
300-450℃×1-2Hr, preferably 300-450℃×
1 to 2 hours, and under the conditions of 300℃ or less x 1 hour or less, the alloying of Ni and P is incomplete;
If it exceeds 2 hours, it will become over-aged and the hardness will decrease. The samples used in Examples 2 and 3 above were the same as those in Experiment 1 in terms of the mating material, its shape, finish, the base material of the pin (upper specimen), shape, finish, and plating conditions. The wear test conditions were also the same as in Experiment 1.

【table】

【table】

[Table] In addition, the reason why the composite ratio of silicon nitride and titanium carbide is set to be 20:80 to 80:20 by volume is the reason why the reciprocating friction test shown in Fig. 7 (hereinafter referred to as Experiment 4 This is because when the proportion of silicon nitride is less than 20%, the wear of the other material increases rapidly, and when it exceeds 80%, the wear of the silicon nitride itself increases. The samples used in Experiment 4 were the same as those in Experiment 1 in terms of mating material, pin base material, shape, finish, and plating conditions, and the contents of the plating were the same as those shown in Table 3. The test conditions were the same as in Experiment 1. The reason why the particle size of silicon nitride is 5 μm or more and 10 μm or less and the particle size of titanium carbide is 1 μm or more and 3 μm or less is as follows. Ni-P plating was performed using various grain sizes of silicon nitride and titanium carbide (and silicon carbide for reference), and a reciprocating friction test (hereinafter referred to as Experiment 5) was performed, as shown in Figure 8. In addition, when the particle size of silicon nitride exceeds 10 μm and the particle size of titanium carbide (and silicon carbide for reference) exceeds 3 μm, wear of the mating material increases rapidly. When considering both its own wear and the wear of the other material, the particle size of silicon nitride should be in the range of 0.5 to 10 μm, and the particle size of titanium carbide should be in the range of 1 to 3 μm. The maximum particle size is 1.0 μm (analytical diameter 0.3 to 1.0 μm). The sample used in Experiment 5 had the same mating material, pin base material, shape, and finishing method as Experiment 1.
is the same as

〔Example〕

Examples of the present invention will be described below. Upper specimen 1 of the reciprocating friction tester shown in Figure 1
(φ8×23 ^L , SK-5, pin) The end face was processed into an 18R spherical surface, and the Ni-P plating according to the present invention was applied by 0.2 mm.
After applying it to a certain thickness, it was polished to an 18R spherical surface. The plating thickness after polishing is 0.15 mm, and the hardness after hardening heat treatment at 350℃ x 1 hr is Si ₃ N ₄ + SiC for reference.
Hmv906 and Hmv896 were Si ₃ N ₄ +TiC of the present invention. The details of the plating at that time are as follows. Bath composition: Nickel sulfamate: 400g/Boric acid: 60g/Sodium hypophosphite: 2g/Pitt inhibitor (sodium lauryl sulfate): 2
ml/ Bath temperature: 53℃ Bath PH: 4.0 Current density: 6A/dm ² /, time: 3.5Hr Composite agent: Si ₃ N ₄ 40g/, SiC (reference example) 40
g/ Si ₃ N ₄ 40 g/, TiC (example of the present invention) 40 g/ The maximum particle size of Si ₃ N ₄ used as a composite material is 1.5μ
m (average particle size 0.6 μm), TiC (and for reference
The maximum particle size of SiC) was 1 μm (average particle size 0.6 μm), and the volume ratio was approximately 50:50 during plating, and the total composite ratio was 20 vol%. As a comparison material, Fe-C-Cr alloy (JIS G2303 equivalent material) made by hard chrome plating and plasma spraying.
Thermal spray was applied to the end face of a φ8×23 ^L pin, which was machined into a 18 ^R spherical surface and used for testing. The hardness of hard chrome plating (no hardening heat treatment applied) is
The hardness of the Fe-C-Cr thermal spraying (no hardening heat treatment was applied) was Hmv958 and Hmv786. As a mating material for the above four types of pins,
FC25 cast iron material was tested using the test machine shown in Figure 1 at 70 ^L ×
It was processed into a flat plate (lower specimen) 2 of 17 ^W × 7 ^t m/m, the test surface was buffed, and a reciprocating friction test was performed. The results are shown in FIG. The test conditions were the same as in Experiment 1 above. In addition, the reference materials in Figure 9 are
It shows Si ₃ N ₄ +SiC. As is clear from FIG. 9, the plating according to the present invention is different from the hard chrome plating of the comparative material and the Fe-C-
Compared to plasma-sprayed Cr material, when using FC25 cast iron material, not only the wear of the material itself but also the wear of the other material is less. Furthermore, it can be seen that the plating according to the present invention has smooth friction surfaces on both itself and the mating material, and has excellent properties as a friction material. Further, FIGS. 10A and 10B show micrographs of the above-mentioned plating according to the present invention and plating for reference at a magnification of 100 times. Figure 10A shows Si ₃ N ₄ +SiC as hard particles.
(Reference example) and FIG. 10B shows the case where Si ₃ N ₄ +TiC (Example of the present invention) were used, respectively. Furthermore, the 10th
In Figures A and B, 11 is the base material (SK-5), 12 is Ni
-P layer 13 is a composite Ni-P plating layer. Ni
-P layer 12 is generated by plating without stirring the liquid during composite plating, and if composite plating is performed directly on the base material (SK-5), poor adhesion will occur. It is created for the purpose of eliminating this. [Effects of the present invention] As described above, in the composite plating of the present invention, when there is little wear on the plate itself, there is a lot of wear on the other side, and when there is little wear on the other side, there is a large amount of wear on the other side. The composite plating of the present invention can eliminate the disadvantage of a large amount of wear on the sliding member and produce a synergistic effect of reducing both the wear and the wear of the other party compared to those obtained by adding it alone. When applied, it exhibits extremely useful effects and has great industrial value.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a known reciprocating friction tester used in the wear test of the present invention, Figure 2 is a diagram showing the method for evaluating the amount of wear, and Figure 3 is a diagram showing various composite materials during Ni-P plating. Figure 4 is a graph showing the results of a wear test conducted to check the wear resistance when Ni was added.
- A graph showing the hardness of the plating layer with changes in the P content in the P plating layer, Fig. 5 is a graph showing the results of wear tests conducted with varying hardness of the plating layer, Fig. 6 is Si Graph showing the results of wear tests with different composite ratios of ₃ N ₄ +SiC and Si ₃ N ₄ +TiC, No. 7
_The figure is a graph showing the results of wear tests conducted by changing the blending ratios of _{Si 3 N 4} and TiC (and SiC for reference). ) is a graph of the wear test results showing the relationship between the particle size and the amount of wear. Figure 9 shows the comparative wear test results of the composite plating according to the present invention and the reference example, the conventional hard chrome plating, and the plasma sprayed material. Graph, 1st
Figures A and B are cross-sectional photographs showing the metal composition of composite plating according to the reference example and the example of the present invention.

Claims (1)

[Claims] 1. Silicon nitride with a grain size of 5 μm or more and 10 μm or less and titanium carbide with a grain size of 1 μm or more and 3 μm or less in a nickel-phosphorus alloy plating layer, such that the composite ratio of the silicon nitride and the titanium carbide is a volume ratio. 20:80 to 80:20, and the total of the silicon nitride and the titanium carbide is dispersed and precipitated at 5 to 30 Vol% on the nickel-phosphorus alloy plating layer. Excellent composite nickel-phosphorus alloy plating. 2. A patent characterized in that the phosphorus content in the composite nickel-phosphorus alloy plating layer is 1 to 8% by weight, and the plating layer that has been subjected to hardening heat treatment has a microvitkers hardness of 800 or more. A composite nickel-phosphorus alloy plating with excellent wear resistance as claimed in claim 1.