JP5386585B2 - Sintered sliding material and manufacturing method thereof - Google Patents

Description

  The present invention relates to a sintered sliding material excellent in heat resistance, corrosion resistance and wear resistance, and a method for producing the same.

  As a sintered sliding material exposed to high-temperature exhaust gas, there is a bearing (see, for example, Patent Document 1) used for a recirculation exhaust gas flow rate adjustment valve of an EGR (Exhaust Gas Recirculation) type internal combustion engine. . And as a bearing used for the recirculation exhaust gas flow control valve of an EGR type internal combustion engine, the thing made from graphite, and the sintered Cu alloy containing Sn: 7-10% and C: 5-9% by mass% The ones made are known.

  However, the recent increase in output and fuel consumption of internal combustion engines is remarkable, and there is a strong demand for weight reduction and compactness of internal combustion engines. For this reason, the above-mentioned recirculation exhaust gas flow rate control valve has been arranged in the vicinity of the combustion chamber of the engine. As a result, it is assumed that the recirculated exhaust gas flow rate control valve is placed in a high temperature environment near 450 ° C. in combination with an increase in the amount of heat generated by the engine as the output increases.

  As a bearing that can be used even in such a high temperature environment, the composition contains Ni: 10 to 30%, Sn: 5 to 12%, C: 3 to 10% by mass%, and the remainder consisting of Cu and inevitable impurities. And what was comprised by the sintered Cu alloy which has the structure | tissue in which the free graphite was disperse-distributed in the base of a Cu-Ni-Sn type solid solution is indicated by patent documents 2.

JP-T-2002-521610 JP 2004-68074 A

  According to the sintered alloy of the above-mentioned Patent Document 2, although excellent wear resistance can be exhibited even in a high temperature environment, a sintered sliding material having further excellent heat resistance and corrosion resistance is desired.

  Accordingly, an object of the present invention is to provide a novel sintered sliding material that is excellent in wear resistance and also excellent in heat resistance and corrosion resistance.

The sintered sliding material of the present invention contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%, with the balance being the balance. It consists of Cu and inevitable impurities.

Moreover, it contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%, and further 0.3 to 10% solid lubrication. And the balance consists of Cu and inevitable impurities.

  Further, there are dispersed alloy phases in which the Sn concentration is higher than the average concentration of Sn in the entire sintered sliding material.

  Further, alloy phases having a P concentration higher than the average concentration of P in the entire sintered sliding material are dispersed.

  The solid lubricant is any of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide.

The manufacturing method of the sintered sliding material of the present invention contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%. The raw material powder is mixed and molded so that the balance is made of Cu and inevitable impurities, and then sintered at 1100 ° C. or lower in a reducing atmosphere.

Moreover, it contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%, and further 0.3 to 10% solid lubrication. The raw material powder is mixed and molded so that the balance is made of Cu and inevitable impurities, and then sintered at 1100 ° C. or lower in a reducing atmosphere.

  The solid lubricant is any of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide.

The sintered sliding material of the present invention contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P by mass%, or further When it contains 0.3 to 10% of a solid lubricant and the balance is made of Cu and inevitable impurities, the wear resistance is excellent, and the heat resistance and corrosion resistance are also excellent.

  Also, the alloy phase whose Sn concentration is higher than the average concentration of Sn in the entire sintered sliding material has higher hardness than the base material, and the hard phase is dispersed and present, so that it has excellent wear resistance. It becomes.

  In addition, the alloy phase whose P concentration is higher than the average concentration of P in the entire sintered sliding material is harder than the base, and the hard phase is dispersed and present, so that it has excellent wear resistance. It becomes.

  Further, the solid lubricant is any one of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide, so that lubricity is imparted and wear resistance is excellent.

The manufacturing method of the sintered sliding material of the present invention contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%. Or further containing 0.3 to 10% of a solid lubricant, mixing and molding the raw material powder so that the balance is made of Cu and inevitable impurities, and then sintering at 1100 ° C. or lower in a reducing atmosphere. Further, it is possible to produce a sintered sliding material that is excellent in wear resistance and also excellent in heat resistance and corrosion resistance.

  Further, the solid lubricant is any one of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide, so that a lubrication is imparted and a sintered sliding material having excellent wear resistance is manufactured. be able to.

It is an electron micrograph in one Example of the sintering sliding material of this invention.

The sintered sliding material of the present invention contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P by mass%, or further It contains 0.3 to 10% of a solid lubricant, and the balance consists of Cu and inevitable impurities. And by this composition, the sintered sliding material of this invention is excellent in abrasion resistance, and also excellent in heat resistance and corrosion resistance.

Moreover, the manufacturing method of the sintered sliding material of the present invention is at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P in mass%. Containing or further containing 0.3 to 10% of a solid lubricant, mixing and molding the raw material powder so that the balance is made of Cu and inevitable impurities, and then sintering at 1100 ° C. or lower in a reducing atmosphere. . In more detail, first, raw material powder is mixed so that it may become said content rate. Then, this is filled in a mold having a required shape and compacted to obtain a molded body having a required density. This molded body is sintered at 1100 ° C. or lower in a reducing atmosphere to obtain a sintered alloy. Finally, the sintered sliding material of the present invention is obtained by sizing the sintered alloy with a mold so as to satisfy the dimensional accuracy of the product.

  Hereinafter, the composition of the sintered sliding material of the present invention will be described in detail. In addition, all content demonstrated below is the mass%.

(A) About Ni Ni has the effect of increasing the heat resistance and corrosion resistance of the sintered sliding material, and forms a solid solution by combining at least one of Sn and P with Cu, and the sintered sliding material. In addition to improving the strength, the sintered sliding material is given wear resistance in a high temperature environment. If Ni is less than 63 %, the heat resistance and corrosion resistance of the sintered sliding material will be insufficient, and if it exceeds 90%, the wear resistance of the sintered sliding material will be significantly reduced. Therefore, the content of Ni is set to 63 to 90%.

(B) About Sn and P Sn has the effect of lowering the melting point of the alloy, and forms a solid solution with a combination of Ni and Cu to improve the strength of the sintered sliding material and to resist the sintered sliding material. Abrasion is imparted. P also has the effect of lowering the melting point of the alloy, and forms a solid solution in combination with Ni and Cu to improve the strength of the sintered sliding material and to impart wear resistance to the sintered sliding material. . It is only necessary to contain at least one of Sn and P. When Sn is contained and P is not contained, when Sn is not contained and P is contained, both of Sn and P are contained. In addition, Sn and P impart wear resistance to the sintered sliding material.

  When only Sn is contained, if the Sn content is less than 2%, the wear resistance of the sintered sliding material becomes insufficient, and if it exceeds 20%, the sintered sliding material will wear the sliding mating member, which is not preferable. . Therefore, the Sn content is 2 to 20%.

  When only P is contained, if the P content is less than 0.1%, the wear resistance of the sintered sliding material becomes insufficient, and if it exceeds 1.2%, the sintered sliding material wears the sliding counterpart material. Therefore, it is not preferable. Therefore, the content of P is set to 0.1 to 1.2%.

  Even when both Sn and P are contained, it is desirable that the contents of Sn and P be within the above range.

(C) Alloy phase By making the Sn content 2 to 20% and sintering at a temperature of 1100 ° C. or lower, the alloy phase has a higher Sn concentration than the average Sn concentration in the entire sintered sliding material. A sintered sliding material present in a dispersed state is obtained. Further, by making the P content 0.1 to 1.2% and sintering at a temperature of 1100 ° C. or less, an alloy phase in which the concentration of P is higher than the average concentration of P in the entire sintered sliding material is obtained. A sintered sliding material present in a dispersed state is obtained. Further, the Sn content is set to 2 to 20%, the P content is set to 0.1 to 1.2%, and sintering is performed at a temperature of 1100 ° C. or less, whereby the Sn and P concentrations are sintered and slid. A sintered sliding material in which alloy phases higher than the average concentrations of Sn and P in the entire material are dispersed is obtained. These alloy phases have higher hardness than the portion where the concentration of Sn and P is not high, and contribute to the wear resistance of the sintered sliding material. In addition, since Ni is a high content of 63 to 90%, it is necessary to increase the sintering temperature as compared with the case where the content of Ni is low, but when the sintering temperature exceeds 1100 ° C., Sn and P The diffusion proceeds and the alloy phase disappears. For this reason, when manufacturing the sintered sliding material in which the alloy phase is dispersed, the sintering temperature needs to be 1100 ° C. or lower. Moreover, in order to make an alloy phase exist, it is preferable that sintering time shall be 10 to 20 minutes.

(D) Solid lubricant The solid lubricant imparts excellent lubricity to the sintered sliding material and contributes to the improvement of the wear resistance of the sintered sliding material. As a solid lubricant, boron nitride, talc (Mg ₃ Si ₄ O ₁₀ (OH) ₂ ), calcium fluoride, graphite, or molybdenum disulfide is contained.

The solid lubricant may be included as necessary. However, when the solid lubricant is included, the effect is not obtained when the solid lubricant is less than 0.3%, and when the solid lubricant exceeds 10%, the sintered sliding is performed. This is not preferable because the strength and abrasion resistance of the material are significantly reduced. Therefore, the content of the solid lubricant is set to 0.3 to 10%. Talc becomes enstatite (MgSiO ₃ ) after sintering.

  It is desirable to use a solid lubricant properly depending on the temperature at which the sintered sliding material is used. Boron nitride, calcium fluoride, talc, graphite, and molybdenum disulfide are effective when the sintered sliding material is used at 500 ° C. or lower, and boron nitride, calcium fluoride, talc is exceeded when it exceeds 500 ° C. Is effective. In addition, when it is 500 ° C. or lower, fluorinated graphite, tungsten disulfide, magnesium silicate mineral powder, and when it exceeds 500 ° C., magnesium silicate mineral powder can be used. Two or more solid lubricants may be added.

  Hereinafter, specific examples of the sintered sliding material of the present invention will be described. In addition, this invention is not limited to a following example, A various deformation | transformation implementation is possible. For example, in the following embodiments, a bearing having a sliding surface on the inner periphery will be described.

As raw material powder, Ni-30% Cu atomized powder with particle size of -100 mesh, Ni-45% Cu atomized powder and Ni-1% Cu atomized powder, Sn atomized powder with particle size of -250 mesh, particle size of -200 mesh Cu-8% P atomized powder, BN powder with an average particle size of 75 μm, MoS ₂ powder with an average particle size of 4 μm, talc powder with a particle size of −200 mesh, graphite powder with a particle size of −150 mesh, CaF with a particle size of −200 mesh _Two powders were prepared. These raw material powders are blended so as to have the final component composition shown in Table 1, 0.5% zinc stearate is added and mixed for 20 minutes with a V-type mixer, and then pressed to produce a green compact. did. In a sintering furnace set at a predetermined temperature in an endothermic gas (endothermic gas) atmosphere obtained by decomposing and transforming natural gas by passing this green compact through a catalyst heated with natural gas and air Was sintered under predetermined furnace passage time conditions, followed by sizing.

  Through the above-described steps, a ring-shaped test piece having various composition components as a bearing and having dimensions of an outer diameter of 18 mm, an inner diameter of 8.020 ± 0.005 mm, and a height of 8 mm (Reference Example 1, Example 2). -35, Comparative Examples 1-10) were produced and tested as follows.

[Abrasion resistance test]
A stainless steel shaft made of SUS304 having an outer diameter of 7.994 to 8.000 mm and subjected to hard chrome plating treatment with a thickness of 10 μm is inserted into each of the ring-shaped test pieces of Reference Example 1, Examples 2-35 and Comparative Examples 1-10. did. A load of 29 N is applied from the outside of the ring-shaped specimen toward the radial direction of the ring-shaped specimen (perpendicular to the axial direction of the stainless steel shaft), and heated so that the ring-shaped specimen is maintained at 120 ° C. A sliding test was performed in which the stainless steel shaft was reciprocated in the range of an arc having a central angle of 90 ° of the ring-shaped test piece under controlled dry conditions where no lubricant was used. The bearing inner diameter and the maximum wear depth of the stainless steel shaft after 250,000 reciprocating sliding tests were measured to evaluate the wear resistance. Further, the wear resistance of the ring-shaped test pieces of some examples was evaluated in the same manner as described above except that the heating was controlled to be maintained at 450 ° C. The results are shown in Table 1 as the maximum wear depth of the bearing and the maximum wear depth of the stainless steel shaft.

[Salt spray test]
A neutral salt spray test was performed on the ring-shaped test pieces of Reference Example 1, Examples 2-35 and Comparative Examples 1-10, and corrosion resistance due to the presence or absence of rust was evaluated. The salt spray test method was performed according to JIS Z 2371, and the occurrence of rust up to 48 hours was evaluated. The results are shown in Table 1 as the presence or absence of corrosion due to salt spray.

  As shown in Table 1, in each of Reference Example 1 and Examples 2 to 35, the alloy phase (Sn rich phase; Sn, Ni, Cu) in which the Sn concentration is higher than the average concentration of Sn in the entire sintered sliding material. And a metal structure in which at least one of the alloy phases (P-rich phase; including P, Ni, and Cu) having a P concentration higher than the average concentration of P in the entire sintered sliding material is dispersed. Was. The presence or absence of Sn-rich phase and P-rich phase was analyzed using an electron microscope and an electron beam microanalyzer.

  In Reference Example 1 and Examples 2-35, the maximum wear depth of the bearing is 0.067 mm or less, the maximum wear depth of the stainless steel shaft is 0.060 or less, corrosion due to salt spray is not seen, and wear resistance and corrosion resistance. It became a thing with. In Examples 13, 14, 19, 20, 28, 29, 31, and 32, it was confirmed that the abrasion resistance at 450 ° C. was high and the heat resistance was also excellent.

  On the other hand, Comparative Examples 1 to 3 in which neither Sn-rich nor P-rich phases exist, Example 5 with a Ni content of 95%, Example 6 with a Sn content of 1%, and nitriding as a solid lubricant In Comparative Example 10 in which the boron content was 12%, the maximum bearing wear depth was increased. Further, in Comparative Example 4 where the Ni content was 35%, there was corrosion due to salt spray. In Comparative Example 7 in which the Sn content was 22% and Comparative Examples 8 and 9 in which the P content was 1.5%, the maximum wear depth of the stainless steel shaft was increased.

  From the above results, it was confirmed that the sintered sliding material of the present invention was excellent in wear resistance, heat resistance, and corrosion resistance.

[Electron beam microanalyzer analysis]
As an example, the analysis result of the ring-shaped test piece of Reference Example 1 will be described.

  The crystal structure present in the ring-shaped test piece of Reference Example 1 was analyzed for Sn, Cu, and Ni using an electron beam microanalyzer (EPMA). The analysis conditions were set at an acceleration voltage of 15 kV and a beam diameter of 1 μm, and as shown in the electron micrograph (COMPO image) in FIG. The average value of the measured values was obtained. The results are shown in Table 2. It was confirmed that there was an alloy phase in which the Sn concentration was higher than the average concentration of Sn in the entire sintered sliding material.

Claims (8)

It contains at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P, and the balance is made of Cu and inevitable impurities. Sintered sliding material. And containing at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P, and further 0.3 to 10% solid lubricant, A sintered sliding material characterized in that the balance is made of Cu and inevitable impurities. The sintered sliding material according to claim 1 or 2, wherein an alloy phase having a Sn concentration higher than the average concentration of Sn in the entire sintered sliding material is dispersed. The sintered sliding material according to claim 1 or 2, wherein an alloy phase having a P concentration higher than the average concentration of P in the entire sintered sliding material is dispersed. The sintered sliding material according to claim 2, wherein the solid lubricant is any one of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide. Raw material powder containing at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P, with the balance being Cu and inevitable impurities. A method for producing a sintered sliding material, which is formed by mixing and sintering at 1100 ° C. or lower in a reducing atmosphere. And containing at least one of 63 to 90% Ni, 2 to 20% Sn and 0.1 to 1.2% P, and further 0.3 to 10% solid lubricant, A raw material powder is mixed and molded so that the balance is made of Cu and inevitable impurities, and then sintered in a reducing atmosphere at 1100 ° C. or lower, and a method for producing a sintered sliding material is provided. The method for manufacturing a sintered sliding material according to claim 7, wherein the solid lubricant is any one of boron nitride, talc, calcium fluoride, graphite, and molybdenum disulfide.

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