JP3370785B2 - Copper-based sintered sliding material - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-based sintered sliding material, and more specifically to a sliding material having a multilayer structure in which copper-based powder is sprinkled and sintered on a backing metal. Is.

[0002]

2. Description of the Related Art The applicant of the present invention discloses in US Pat. No. 5,279,638 (issued on January 18, 1994) that a Cu-Sn alloy constituting a sliding layer of a sliding material having the above-mentioned multilayer structure is used as hard particles. Fe ₂ P, Fe ₃ P, FeB, Fe ₂ B, Mo, Co, Co-based self-fluxing alloy, Ni-based self-fluxing alloy, SiC, TiC, WC, B ₄ C, TiN,
Cubic BN, Si ₃ N ₄ , SiO ₂ , ZrO ₂ , Al ₂ O ₃ , Si-Mn, Cu-
It has been proposed that the addition of Si, and / or FeS enhances the wear resistance against the sliding mating material when the surface is rough.

It is also known that a copper-based sliding material containing Pb is likely to corrode when the lubricating oil deteriorates. As a countermeasure against this, U.S. Pat.
No. 8768 proposes adding indium to the lead phase. In addition, it is also disclosed that Sn, Ni, Sb, Al, Fe, Mn, and Zn are added to copper as elements that improve corrosion resistance or mechanical properties.

[0004]

Although the wear resistance of the sliding material has been improved by the above-mentioned hard additives, it is due to the fact that the load applied to the bearing has increased in recent years under high load conditions and the sliding speed has increased. As the bearing is used under high peripheral speed conditions and / or boundary lubrication conditions with a decrease in the amount of lubricating oil,
The above sliding materials had insufficient wear resistance and seizure resistance.

Although Sn, Sb and Al improve the corrosion resistance of copper against deteriorated lubricating oil, their effect is limited. Further, In significantly improves the corrosion resistance of lead, but is not very effective in improving the corrosion resistance of copper itself.

Accordingly, the first object of the present invention is to improve the wear resistance and seizure resistance of a copper-based sintered sliding material used under high load conditions, high peripheral speed conditions and / or boundary lubrication conditions. To aim. Further, in addition to the above conditions, the present invention aims to improve the wear resistance, seizure resistance and corrosion resistance of a copper-based sintered sliding material used under corrosive conditions due to deterioration of lubricating oil. To aim.

[0007]

A copper-based sintered sliding material that achieves the first object of the present invention is 5 to 40% by weight Zn and 5 to 50% by weight.
In a copper-based sintered sliding material obtained by sintering Cu or a Cu alloy containing one or more kinds of Ni by weight, the average particle size is 1 to 30.
The copper-based sintered sliding material, which is characterized by adding 0.2 to 15% by weight of aluminum nitride particles of μm and dispersed, and which achieves the second object, is a copper-based sintered material obtained by sintering Cu or a Cu alloy. In the binding and sliding material, the Cu or Cu alloy should be added with 0.1
.About.5% by weight of Ag and 0.2 to 15% by weight of aluminum nitride particles having an average particle size of 1 to 30 .mu.m are added and dispersed. The configuration of the present invention will be described in detail below.

Aluminum nitride (hereinafter referred to as "aluminum nitride"), which has a structure common to both the first and second aspects of the present invention, has been attracting attention as a material for a semiconductor substrate, but its application to a sliding material has been studied. Didn't. The present inventors have studied aluminum nitride based on experiments and found the following points.
First, conventional Al ₂ O ₃ , SiC and the like are preferable tribological property improving components which have a marked tendency to increase the friction coefficient of copper-based sliding materials, but do not have such a tendency to aluminum nitride.

Generally, ceramic particles have poorer adhesion to copper matrix than metal particles, but aluminum nitride has good adhesion to copper matrix. Therefore, aluminum nitride is less likely to fall off the copper base during sliding.

Aluminum nitride has a specific gravity of about 3.2 g / cm ³ , and Fe ₃ P has a specific gravity of about 6.7 g / cm ³ . In general, the effect of hard particles on the sliding surface is proportional to the area of contact with the mating material, so aluminum nitride occupies a larger area than Fe ₃ P with the same added weight, and as a result, the sliding characteristic improving effect is large. Further, the amount of particles dropped off during sliding is proportional to the added weight, so that the amount of aluminum nitride dropped can be smaller than that of Fe ₃ P having the same area.

Aluminum nitride has a hardness of about Hv = 1000 to 1
The value is 300, which is comparable to that of TiN which is a conventional hard material additive. Therefore, chambered aluminum has a great effect of increasing the hardness of the copper-based sintered material and imparting wear resistance.

The inventors of the present invention have found that aluminum nitride has a greater effect of improving sliding characteristics than conventional hard material additives, and that this also has the above-mentioned properties, thereby completing the present invention. It was done. Further, if the amount of aluminum nitride added is less than 0.2% by weight, there is almost no effect of improving the sliding characteristics, while if it exceeds 15% by weight, the friction coefficient becomes high and the amount of particles falling off becomes large. On the contrary, the sliding property is rather deteriorated. Therefore, the addition amount of aluminum nitride needs to be in the range of 0.2 to 15% by weight with respect to the entire sliding layer, and the preferable addition amount is 0.5 to 10% by weight, more preferably 1 to 5% by weight. %.

It is necessary that the aluminum nitride particles and the copper or copper alloy particles are evenly distributed in each other. If the aluminum nitride is whiskers, needles, plates or the like, it is difficult to achieve a uniform distribution when mixed with copper (alloy) particles. Therefore, it is preferable to use granular or massive aluminum nitride. Granular aluminum nitride can be easily prepared by nitriding an aluminum plate and crushing.

The copper or copper alloy particles may be those conventionally known. That is, Pb, Sn, Sb, Al, In,
0.5 to 40% by weight of one or more elements that improve the sliding characteristics of copper such as P, Si, graphite and MoS ₂ may be added. Although a heavy metal element such as Fe, Co, Mn, or Cr that hardens the copper matrix to improve the wear resistance may be added in an amount of 10% by weight or less, the improvement of the wear resistance of aluminum nitride is utilized to make the copper matrix familiar. It is better to avoid the positive addition of heavy metals in order to maintain good properties and lubricity.

Although the system made of the combination of pure copper and aluminum nitride does not contain Pb and Sn which are soft metals, the sliding characteristics are better than the Kelmet grade if the lubricating conditions are relatively good. .

The copper or copper alloy particles may be general atomized powder, crushed powder, electrolytic powder, etc., and their particle sizes are general, and it is preferable to use particles of 1 μm to 100 μm in particular. it can.

A second aspect of the present invention is characterized in that copper or a copper alloy contains Ag in addition to the above-mentioned dispersion and addition of aluminum nitride. The present inventors conducted a wear test on a copper-based sliding material added with Ag in deteriorated lubricating oil, and then chemically analyzed the sliding surface, whereby Ag and S were concentrated and the progress of corrosion was stopped. It was found that it was completed. Here, S is contained in the corrosive organic compound of the deteriorated lubricating oil, and Cu and P are contained if Ag is not contained.
The amount of the copper alloy is reduced by chemically reacting with b or the like, and the reaction product is dissolved in the lubricating oil. But A
When g is contained, a chemical reaction with S occurs, but an Ag-S concentrated layer is stably formed on the surface, and the corrosion thereafter slows down. Further, in a copper alloy to which an element that easily causes corrosion such as Pb is added, if the addition amount of Ag is increased to preferably 0.2% or more, corrosion due to Pb can be suppressed and excellent corrosion resistance can be achieved. In addition, the above A
Since the effect of g is remarkable in the presence of pressure from the mating material, wear resistance and seizure resistance are remarkably enhanced in a corrosive environment.

If the added amount of Ag is less than 0.1% by weight, the effect of improving the corrosion resistance is not obtained. If the added amount of Ag exceeds 5% by weight, the effect of improving the corrosion resistance does not increase even if the added amount is large. It should be in the range of 0.1 to 5% by weight, preferably 0.2 to 2% by weight, more preferably 0.1.
It is 3 to 1% by weight.

The first aspect of the present invention is characterized in that the copper alloy contains Zn and / or Ni. Zn and Ni are elements that make it difficult for the copper alloy to react with the S component in the deteriorated lubricating oil. If the added amount of Zn and / or Ni is less than 5% by weight, there is almost no effect of improving the corrosion resistance. On the other hand, when Zn exceeds 40% by weight, the sliding characteristics are deteriorated due to precipitation hardening, and when Ni exceeds 50% by weight, the particles are apt to adhere to the mating shaft and the sliding characteristics are deteriorated. The added amount of Ni needs to be 5 to 40% by weight and 5 to 50% by weight, respectively, preferably 10 to 35% by weight, and more preferably 15 to 30% by weight. When Ag and Zn and / or Ni are added at the same time, the lower limit of the amount of Zn and / or Ni added can be 0.5%.

In the present invention, the sliding characteristics are not improved as much as the addition of aluminum nitride even if the hard materials listed in Paragraph No. 0002 are added, but if the same amount or less is added to aluminum nitride, the effect of aluminum nitride is Not damaged. When the addition ratio exceeds the same amount, Fe ₃ P and the like fall off, the friction coefficient increases, and the effect of aluminum nitride is impaired.

The method for producing the sintered sliding material according to the present invention will be described below. This method is described in Applicant's US Pat.
It is basically the same as the general method described in column 3, lines 21-28 of 279638. However, since aluminum nitride has a specific gravity of less than about 1/2 that of copper (alloy) powder, in order to uniformly disperse the former, the rotation speed of the V-type blender is lowered and stirring is performed slowly. Points are important. Also, the mixed powder of copper (alloy) powder and aluminum nitride is sprayed to a thickness of about 1 mm to several mm, and light pressure is applied as it is or to the extent that the uneven surface thickness is somewhat smoothed. Then, the powder is sintered without pressure. After that, it is preferable to perform roll reduction to reduce the thickness by about 50 to 70% and further perform the second sintering.
The sintering is preferably performed at 700 to 900 ° C. in a reducing atmosphere.

[0022]

[Function] According to the above-mentioned manufacturing method, a sintered sliding material having the same thickness and containing various additives or additive elements is manufactured and tested for wear resistance, seizure resistance and corrosion resistance, and various sliding material compositions are used. The changes in characteristics were investigated.

Abrasion resistance Abrasion resistance test conditions (1) Cylindrical / flat plate test (2) Lubricant-liquid paraffin (Cristol Energy:
(3) Temperature-150 ° C (4) Test time-1 hour (5) Sliding speed-0.5m / sec (6) Mating material-S50C (7) Load-10kgf

The test results test materials ratio wear amount (mm ² / kg) Kerumetto sintered material (Cu-Pb) 6 × 10 -8 Cu-3wt% Fe 3 P 3.7 × 10 -8 Cu-1wt% AlN 3.6 x 10 ^-9

Fe ₃ P had an average particle size of 25 μm, and aluminum nitride had a lump shape with an average particle size of 6 μm. The additive weights of Fe ₃ P and aluminum nitride were adjusted so that the volume ratio was the same. The hardness of Cu-3 wt% Fe ₃ P was Hv 105, and the hardness of Cu-1 wt% AlN was Hv 101.

From the above results, it can be seen that aluminum nitride reduces the specific wear amount by about 10 times that of Fe ₃ P and is very effective in improving the wear resistance.

Seizure resistance (1) Seizure resistance 3 pin / disk test (2) Lubricant-liquid paraffin (Cristol Energy) (3) Temperature -20 ° C (5) Sliding speed -1 m / sec (6) Counterpart Material-SUJ2 (7) Load-30kgf / 15min Gradually increase

The test results test materials seizure surface pressure (MPa) Kerumetto sintered material (Cu-Pb) 12 Cu- 3wt% Fe 3 P 15 Cu-1wt% AlN 20

From the above results, it can be seen that aluminum nitride has a baking surface pressure about 30% higher than that of Fe ₃ P, and is therefore very effective in improving the seizure resistance.

Corrosion Resistance (Oil Boil Test) The following test materials (weight = 1.5 g) were boiled at 180 ° C. in deteriorated diesel oil for 24 hours to examine the amount of corrosion.

The test results test materials corrosion amount (mg) Kerumetto sintered material (Cu-Pb) 120 phosphor bronze (0.2% P) 95 Cu- 1wt % AlN 80 Cu- 1wt% Ag-1wt% AlN 45 Cu -25 wt% Zn-1 wt% AlN 5 Cu-10 wt% Ni-1 wt% AlN 6

Kelmet contains Pb and thus has poor corrosion resistance, but addition of P and removal of Pb improve corrosion resistance (phosphor bronze). In addition, the addition of Ag significantly improves the corrosion resistance. The corrosion resistance is further improved by adding Zn.

Corrosion wear resistance Corrosion wear resistance test conditions (1) Cylinder / plate test (2) Lubricant-degraded diesel oil (3) Temperature-150 ° C (4) Test time-8 hours (5) Sliding speed -0.5 m / sec (6) Counterpart material-S50C (7) Load-10 kgf The abrasion resistance test conditions were corrected so that corrosion was likely to occur, and the test was conducted.

Test Results Test Material Specific Amount of Wear (mm ² / kg ) Kelmet Sintered Material (Cu-Pb) 8 × 10 ^-8 Phosphor Bronze (0.2% P) 8 × 10 ^-8 Cu-1 wt% AlN 3.6 × 10 ^-9 Cu-1 wt% Ag-1 wt% AlN 9 × 10 ^-10 Cu-25 wt% Zn-1 wt% AlN 4 × 10 ^-9

Although this result is almost the same as the corrosion resistance,
The performance has been improved by adding only 1N, and Z
The difference is that n has a smaller performance improving effect than AlN.

Corrosion and seizure resistance Corrosion and seizure resistance test conditions (1) multi-area tester (2) lubricant-degraded engine oil (7.5W-30) (3) temperature -150 ° C (4) test time -8 Time (5) Sliding speed -15 m / sec (6) Counterpart material-S50C (7) Load -20 kgf / 5 min at a rate of 200 kg
Increased up to f, and then increased at a rate of 40 kgf / 10 min. The above-mentioned conditions of the seizure resistance test were corrected so that corrosion was likely to occur, and the test was conducted.

The test results test materials seizure load (kgf) Kerumetto sintered material (Cu-Pb) 400 phosphor bronze (0.2% P) 300 Cu- 1wt % AlN 550 Cu- 1wt% Ag-1wt% AlN 700 Cu -25wt% Zn-1wt% AlN 500

The seizure test in the multi-area tester is a test close to the performance in an actual machine using deteriorated lubricating oil. From this result, it is clear that excellent seizure resistance can be realized by adding aluminum nitride and Ag or Zn in combination with copper. Hereinafter, the present invention will be described in more detail with reference to examples.

[0039]

EXAMPLE Copper or copper alloy powder having a particle size of -100 mesh and massive aluminum nitride (Al having an average particle size of 6.6 μm)
N) were mixed in the proportions shown in Table 1. For comparison, Fe3 P was also added. These mixed powders were sprinkled on a steel plate to a thickness of about 1 mm, and then intermediate roll reduction was performed to reduce the thickness to 0.3 mm, and two-stage sintering was performed. The sintering temperature was 900 ° C. for 30 minutes.
Tables 1 to 3 show the results of the seizure resistance and corrosion seizure resistance tests of the obtained material under the above conditions.

As a comparative material to which AlN was not added, a sliding material having the following composition (%) was prepared in the same manner as in the example. Cu Ag Ni Sn Pb Fe ₃ P No Amount μm 48 Remaining − − 10 10 − − 49 Remaining 11 1 − − 3 20

The specific wear amount, seizure-resistant surface pressure and corrosion amount of the comparative material are as follows, and were significantly inferior to the performance of the examples of the present invention.

[0042]

As described above, according to the present invention, the wear resistance and seizure resistance superior to those of conventional copper-based sintered sliding materials containing hard particles and their performance in deteriorated lubricating oil and Corrosion resistance can be obtained. Therefore, the present invention can contribute to the performance improvement of the sliding member, which has been used under severe conditions in recent years, and can provide a sliding material having extremely high practicality. In particular, the sliding material of the present invention is expected to exhibit excellent performance when used as an automatic transmission for an engine or the like.

[Brief description of drawings]

FIG. 1 shows a material No. according to an embodiment of the present invention. It is a chart which described the composition of 1-15, the amount of specific wear, the seizure surface pressure, and the amount of corrosion.

FIG. 2 shows a material No. according to an embodiment of the present invention. It is a chart which described the composition of 16 to 30, the specific wear amount, the seizure surface pressure, and the corrosion amount.

FIG. 3 shows a material No. according to an embodiment of the present invention. It is a chart which described the composition of 31-47, the specific wear amount, the seizure surface pressure, and the corrosion amount.

Continuation of the front page (56) Reference JP-A-6-145845 (JP, A) JP-A-2-133537 (JP, A) JP-A-4-131340 (JP, A) JP-A-54-163704 (JP , A) JP 64-39307 (JP, A) JP 5-279772 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22C 9/00 C22C 1/04 C22C 9/04 C22C 9/06 C22C 32/00

Claims (4)

(57) [Claims] 1. 5-40% by weight Zn and 5-50% by weight N
In a copper-based sintered sliding material obtained by sintering Cu or a Cu alloy to which at least one of i is added, 0.2 to 15% by weight of aluminum nitride particles having an average particle size of 1 to 30 μm are added and dispersed. Copper-based sliding material 2. A copper-based sintered sliding material obtained by sintering Cu or a Cu alloy, in which 0.1 to 5% by weight of Ag is added to the Cu or Cu alloy and the average particle size is 1 to 30 μm. A copper-based sintered sliding material comprising 0.2 to 20% by weight of aluminum particles dispersed therein. 3. 0.5 to 40% by weight Zn and 0.5 to 50% by weight
The copper-based sintered sliding material according to claim 2, wherein one or more kinds of Ni are added to the Cu or Cu alloy. 4. The copper-based sintered slide according to claim 1, wherein the backing metal is sintered in a non-pressurized state or a substantially non-pressurized state. material.