A silver-based solid lubricating material and its preparation method and application

Abstract

This invention relates to the field of conductive slip ring lubrication technology, and more particularly to a silver-based solid lubricant material, its preparation method, and its application. The invention provides a silver-based solid lubricant material, which, by mass percentage, comprises the following raw materials: 74-92% metallic silver, 0.5-1.5% metallic tantalum, 0.5-1.5% metallic titanium, 1.0-4.5% molybdenum disulfide, 1.0-4.5% tungsten disulfide, 1.0-4.5% niobium diselenide, 0.5-1.5% graphite, 1.5-3.5% antimony thioantimonate, 0.5-1.0% lanthanum fluoride, and 1.5-3.5% antimony trioxide. This silver-based solid lubricant material can improve the tribological properties of the brush-slip ring friction pair in a vacuum environment, thereby increasing the service life of the conductive slip ring in a vacuum environment.

Description

Technical Field

[0001] This invention relates to the field of conductive slip ring lubrication technology, and in particular to a silver-based solid lubricating material, its preparation method, and its application. Background Technology

[0002] A conductive slip ring is a precision device that enables signal and power transmission between rotating and stationary components. In the aerospace field, conductive slip rings are widely used in various applications requiring rotational communication, such as satellites, rockets, and spacecraft. With the continuous advancement of aerospace technology and the rapid development of deep spaceflight, the lifespan requirements for conductive slip rings are becoming increasingly stringent. The frictional wear performance between the brush bristles and the slip ring determines its lifespan. Therefore, improving the frictional wear performance between the slip ring and the brush bristles is one of the technical approaches to achieving a long lifespan (greater than 20 million revolutions) for conductive slip rings. Summary of the Invention

[0003] The purpose of this invention is to provide a silver-based solid lubricant material, its preparation method, and its application. The silver-based solid lubricant material can improve the tribological properties of the brush-slip ring friction pair in a vacuum environment, thereby increasing the service life of the conductive slip ring in a vacuum environment.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] This invention provides a silver-based solid lubricant material. The raw materials for preparing the silver-based solid lubricant material, by mass percentage, include: 74-92% metallic silver, 0.5-1.5% metallic tantalum, 0.5-1.5% metallic titanium, 1.0-4.5% molybdenum disulfide, 1.0-4.5% tungsten disulfide, 1.0-4.5% niobium diselenide, 0.5-1.5% graphite, 1.5-3.5% antimony thioantimonate, 0.5-1.0% lanthanum fluoride, and 1.5-3.5% antimony trioxide.

[0006] Preferably, the raw materials for preparing the silver-based solid lubricant, by mass percentage, include: 78-88% metallic silver, 1.0-1.5% metallic tantalum, 1.0-1.5% metallic titanium, 2.0-4.5% molybdenum disulfide, 1.0-3.5% tungsten disulfide, 1.0-2.5% niobium diselenide, 0.5-1.0% graphite, 2.0-3.0% antimony thioantimonate, 0.8-1.0% lanthanum fluoride, and 2.0-3.0% antimony trioxide;

[0007] Furthermore, the sum of the mass percentages of the raw materials used in the preparation of the silver-based solid lubricant is 100%.

[0008] This invention also provides a method for preparing the silver-based solid lubricant material described in the above technical solution, comprising the following steps:

[0009] Molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride, and antimony trioxide were ball-milled to obtain a premixed non-metallic powder.

[0010] The premixed non-metallic powder, silver, tantalum and titanium are mixed and then hot-pressed and sintered to obtain the silver-based solid lubricant material.

[0011] Preferably, the particle size of the molybdenum disulfide, tungsten disulfide and niobium diselenide is independently 1 to 10 mm.

[0012] Preferably, the graphite has a particle size of 5–25 mm.

[0013] Preferably, the particle size of the antimony thioantimonate, lanthanum fluoride and antimony trioxide is independently ≤10 mm.

[0014] Preferably, the metallic silver is a -200 mesh whole powder; the particle size of the metallic tantalum and metallic titanium is independently <10 mm.

[0015] Preferably, the ball milling mixing time is 4-8 hours, and the mixing time is 2-6 hours.

[0016] Preferably, the hot pressing sintering is performed at a sintering pressure of 30–80 MPa, a sintering temperature of 650–690 °C, and a holding time of 2–6 h.

[0017] The present invention also provides the application of the silver-based solid lubricating material described in the above technical solution or the silver-based solid lubricating material prepared by the preparation method described in the above technical solution in conductive slip rings.

[0018] This invention provides a silver-based solid lubricant material. The raw materials for preparing the silver-based solid lubricant material, by mass percentage, include: 74-92% metallic silver, 0.5-1.5% metallic tantalum, 0.5-1.5% metallic titanium, 1.0-4.5% molybdenum disulfide, 1.0-4.5% tungsten disulfide, 1.0-4.5% niobium diselenide, 0.5-1.5% graphite, 1.5-3.5% antimony thioantimonate, 0.5-1.0% lanthanum fluoride, and 1.5-3.5% antimony trioxide. The silver-based solid lubricant material of this invention uses silver as a matrix and adds solid lubricants (molybdenum disulfide, tungsten disulfide, niobium diselenide, and graphite) and film-forming additives (antimony thioantimonate, lanthanum fluoride, and antimony trioxide) to achieve excellent transferability, film-forming properties, and conductive lubrication properties. When this silver-based solid lubricant material is applied to a conductive slip ring, contacting the slip ring, the lubrication provided by the silver-based solid lubricant improves the tribological properties of the brush-slip ring friction pair in a vacuum environment, thereby achieving a long service life of the conductive slip ring in a vacuum. The results of the embodiments show that the coefficient of friction of the silver-based solid lubricant material of this invention in a vacuum is 0.05–0.15, and the wear rate in a vacuum is 1.5 × 10⁻⁶. -5 ~8.0×10 -5 mm 3 / Nm. Attached Figure Description

[0019] Figure 1 The image shows the microstructure of the silver-based solid lubricant material described in Example 1.

[0020] Figure 2 This is a schematic diagram of the conductive slip ring described in the application example, where 11 is the slip ring, 12 is the filamentous brush, 13 is the support, and 14 is the solid lubricating block. Detailed Implementation

[0021] This invention provides a silver-based solid lubricant material. The raw materials for preparing the silver-based solid lubricant material, by mass percentage, include: 74-92% metallic silver, 0.5-1.5% metallic tantalum, 0.5-1.5% metallic titanium, 1.0-4.5% molybdenum disulfide, 1.0-4.5% tungsten disulfide, 1.0-4.5% niobium diselenide, 0.5-1.5% graphite, 1.5-3.5% antimony thioantimonate, 0.5-1.0% lanthanum fluoride, and 1.5-3.5% antimony trioxide.

[0022] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0023] The raw materials for preparing the silver-based solid lubricant material of the present invention, by weight percentage, comprise 74-92% metallic silver, preferably 78-88%. In embodiments of the present invention, the weight percentage of metallic silver can be 83.5% or 86.7%. In the present invention, the metallic silver serves as the matrix material in the silver-based solid lubricant material.

[0024] The raw materials for preparing the silver-based solid lubricant of the present invention, by weight percentage, include 0.5-1.5% tantalum metal, preferably 1.0-1.5%. In embodiments of the present invention, the weight percentage of tantalum metal can be 1.0% or 1.5%.

[0025] In this invention, the tantalum metal, as a hard phase, can be dispersed in the silver-based solid lubricant material, becoming a microscopic support point on the friction surface of the silver-based solid lubricant material, thereby improving the hardness and wear resistance of the silver-based solid lubricant material.

[0026] The raw materials for preparing the silver-based solid lubricant material of the present invention, by weight percentage, include 0.5-1.5% titanium, preferably 1.0-1.5%. In embodiments of the present invention, the weight percentage of titanium may be 1.0% or 1.5%.

[0027] In this invention, since there is a small amount of atomic oxygen in space, metallic titanium can preferentially react with atomic oxygen, thereby preventing the oxidation of molybdenum disulfide. At the same time, the presence of titanium can enhance the strength of the silver-based solid lubricant transfer film.

[0028] The raw materials for preparing the silver-based solid lubricant material of the present invention, by weight percentage, include 1.0-4.5% molybdenum disulfide, preferably 2.0-4.5%. In embodiments of the present invention, the weight percentage of molybdenum disulfide may be 3.5% or 2.0%.

[0029] The raw materials for preparing the silver-based solid lubricant of the present invention, by weight percentage, include 1.0-4.5% tungsten disulfide, preferably 1.0-3.5%. In embodiments of the present invention, the weight percentage of tungsten disulfide may be 3.0% or 1.5%.

[0030] The raw materials for preparing the silver-based solid lubricant material of the present invention, based on mass percentage, include 1.0-4.5% niobium diselenide, preferably 1.0-2.5%. In embodiments of the present invention, the mass percentage of niobium diselenide may be 2.0% or 1.0%.

[0031] The raw materials for preparing the silver-based solid lubricant material of the present invention, based on mass percentage, include 0.5-1.5% graphite, preferably 0.5-1.0%. In embodiments of the present invention, the mass percentage of graphite may be 1.0%.

[0032] In this invention, the composite of molybdenum disulfide, tungsten disulfide, niobium diselenide, and graphite exhibits a synergistic effect in a vacuum environment. This invention regulates the friction transfer performance, friction reduction performance, wear resistance, and electrical conductivity of the silver-based solid lubricant by adjusting the content ratio of the above four substances.

[0033] The raw materials for preparing the silver-based solid lubricant material of the present invention, based on mass percentage, include 1.5-3.5% antimony thioantimonate, preferably 2.0-3.0%. In embodiments of the present invention, the mass percentage of antimony thioantimonate can be 2.0%.

[0034] In this invention, the antimony thioantimonate can improve the integrity of the transfer membrane.

[0035] The raw materials for preparing the silver-based solid lubricant material of the present invention, based on mass percentage, include 0.5-1.0% lanthanum fluoride, preferably 0.8-1.0%. In embodiments of the present invention, the mass percentage of lanthanum fluoride may be 1.0% or 0.8%.

[0036] In this invention, the lanthanum fluoride can improve the wear resistance of the transfer film.

[0037] The raw materials for preparing the silver-based solid lubricant material of the present invention, based on mass percentage, include 1.5-3.5% antimony dioxide, preferably 2.0-3.0%. In embodiments of the present invention, the mass percentage of antimony trioxide may be 2.0%.

[0038] In this invention, the antimony dioxide can reduce the harmfulness of molybdenum trioxide generated by the oxidation of the transfer membrane.

[0039] In this invention, the combined use of antimony thioantimonate, lanthanum fluoride, and antimony trioxide can improve the integrity and wear resistance of the transfer film of the silver-based solid lubricant material described in this invention, as well as reduce the harmfulness of molybdenum trioxide generated by the oxidation of molybdenum disulfide transfer film.

[0040] This invention also provides a method for preparing the silver-based solid lubricant material described in the above technical solution, comprising the following steps:

[0041] Molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride, and antimony trioxide were ball-milled to obtain a premixed non-metallic powder.

[0042] The premixed non-metallic powder, silver, tantalum and titanium are mixed and then hot-pressed and sintered to obtain the silver-based solid lubricant material.

[0043] This invention involves ball milling and mixing molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride, and antimony trioxide to obtain a premixed non-metallic powder.

[0044] In this invention, the particle size of molybdenum disulfide, tungsten disulfide, and niobium diselenide is preferably 1–10 mm. The particle size of graphite is preferably 5–25 mm. The particle size of antimony thioantimonate, lanthanum fluoride, and antimony trioxide is preferably ≤10 mm.

[0045] In this invention, the ball milling speed is preferably 100-200 rpm, more preferably 120-180 rpm; the time is preferably 4-8 h, more preferably 5-6 h. In an embodiment of this invention, the ball milling speed can be 150 rpm, and the time can be 6 h or 5 h.

[0046] After obtaining the premixed non-metallic powder, the present invention mixes the premixed non-metallic powder, silver, tantalum and titanium, and then performs hot pressing sintering to obtain the silver-based solid lubricant material.

[0047] In this invention, the metallic silver is preferably -200 mesh whole powder; the particle size of the metallic tantalum and metallic titanium is independently preferably <10 mm.

[0048] In this invention, the mixing method is preferably ballless mixing; the ballless mixing speed is preferably 100-200 rpm, more preferably 120-180 rpm; the mixing time is preferably 2-6 hours, more preferably 4-5 hours. In an embodiment of this invention, the ballless mixing speed can be 150 rpm, and the mixing time can be 4 hours. In this invention, the ballless mixing is preferably carried out in a ball mill.

[0049] In this invention, the sintering pressure of the hot-pressing sintering is preferably 30-80 MPa, more preferably 40-60 MPa; the sintering temperature is preferably 650-690℃, more preferably 660-680℃; and the holding time is preferably 2-6 h, more preferably 3-5 h. In an embodiment of this invention, the sintering pressure of the hot-pressing sintering can be 50 MPa, the sintering temperature can be 670℃ or 680℃, and the holding time can be 3 h. In an embodiment of this invention, the hot-pressing sintering specifically involves placing the material obtained after the ballless mixing into a steel mold for hot-pressing sintering.

[0050] The present invention also provides the application of the silver-based solid lubricating material described in the above technical solution or the silver-based solid lubricating material prepared by the preparation method described in the above technical solution in conductive slip rings.

[0051] In this invention, the preferred method is to prepare the silver-based solid lubricant material described in the above technical solution into a solid lubricant block, and then install it into the conductive slip ring. This invention does not impose any special limitations on the preparation process of the solid lubricant block; any process well-known to those skilled in the art can be used. In embodiments of this invention, the structure of the conductive slip ring (e.g.) Figure 2 The preferred embodiment (shown) includes a slip ring 11, a filamentous brush 12, a support 13, and a solid lubricant block 14. The filamentous brush 12 and the solid lubricant block 14 are respectively mounted on opposite sides of the support, and the filamentous brush 12 and the solid lubricant block 14 are in contact with the slip ring 11. In this invention, the contact pressure is preferably 10-50 kPa, more preferably 20-30 kPa. In this invention, the solid lubricant block 14 is a solid lubricant block prepared from the silver-based solid lubricant material described in the above technical solution, and the curvature of the friction surface of the solid lubricant block 14 is consistent with the curvature of the slip ring 11.

[0052] In this invention, during the rotation of the slip ring, friction is generated between the solid lubricating block and the slip ring surface under a certain pressure. This transfers the solid lubricant from the solid lubricating block to the slip ring surface, forming an extremely thin solid lubricating film, thus lubricating the brush / slip ring friction pair. The extremely thin lubricating film formed on the slip ring surface has a certain conductivity, and the resulting resistance is controlled within the acceptable range of the slip ring circuit. The lubricating block continuously provides lubricant to the slip ring friction surface, greatly extending the lifespan of the conductive slip ring.

[0053] The following detailed description of the silver-based solid lubricant material, its preparation method, and its application provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0054] Example 1

[0055] Raw materials and their mass percentages: Silver (Ag, 83.5%) powder with a particle size of -200 mesh and a purity of 99.9%; Tantalum (Ta, 1.0%) and Titanium (Ti, 1.0%) with particle sizes of 1–10 mm and a purity of 99.9%; Molybdenum disulfide (MoS2, 3.5%), Tungsten disulfide (WS2, 3.0%), and Niobium diselenide (NbSe2, 2.0%) with particle sizes of 1–10 mm and a purity of 99.5%; Graphite (C, 1.0%) with particle sizes of 5–25 mm and a purity of 99.0%; Antimony thioantimonate (SbSbS2, 2.0%), Lanthanum fluoride (LaF3, 1.0%), and Antimony trioxide (Sb2O3, 2.0%) with particle sizes of 1–10 mm and a purity of 99.5%.

[0056] Preparation method: Molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride and antimony trioxide were ball-milled in a ball mill (150 rpm for 6 h) to obtain a premixed non-metallic powder.

[0057] The premixed non-metallic powder, silver, tantalum and titanium were mixed in a ball mill without balls (150 rpm for 4 hours). The resulting powder was hot-pressed and sintered (680°C for 3 hours and 50 MPa), and then cooled in the furnace to obtain a silver-based solid lubricant.

[0058] Figure 1 The image shows the microstructure of the silver-based solid lubricant material, where the white portion represents the metallic component and the black portion represents the non-metallic component, forming a solid lubricant material with a metallic matrix and non-metallic components as the lubricant.

[0059] The performance testing standards and results of the silver-based solid lubricant are shown in Table 1.

[0060] Table 1 shows the performance test standards and results of the silver-based solid lubricants.

[0061] Test Project Test standards Test Results Brinell hardness / HB GB / T231.1-2018 32 Yield strength / MPa GB / T7314-2017 129 coefficient of friction GB / T12444-2006 0.09 <![CDATA[Wear rate / × 10 -5 mm 3 / (Nm)]]> GB / T12444-2006 3.6

[0062] Example 2

[0063] Raw materials and their mass percentages: Silver (Ag, 86.7%) powder with a particle size of -200 mesh and a purity of 99.9%; Tantalum (Ta, 1.5%) and Titanium (Ti, 1.5%) with particle sizes of 1–10 mm and a purity of 99.9%; Molybdenum disulfide (MoS2, 2.0%), Tungsten disulfide (WS2, 1.5%), and Niobium diselenide (NbSe2, 1.0%) with particle sizes of 1–10 mm and a purity of 99.5%; Graphite (C, 1.0%) with particle sizes of 5–25 mm and a purity of 99.0%; Antimony thioantimonate (SbSbS2, 2.0%), Lanthanum fluoride (LaF3, 0.8%), and Antimony trioxide (Sb2O3, 2.0%) with particle sizes of 1–10 mm and a purity of 99.5%.

[0064] Preparation method: Molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride and antimony trioxide are ball-milled in a ball mill (150 rpm for 5 h) to obtain a premixed non-metallic powder.

[0065] The premixed non-metallic powder, silver, tantalum and titanium were mixed in a ball mill without balls (150 rpm for 4 hours). The resulting powder was then hot-pressed and sintered (670°C for 3 hours and 50 MPa), and cooled in the furnace to obtain a silver-based solid lubricant.

[0066] The performance testing standards and results of the silver-based solid lubricant are shown in Table 2.

[0067] Table 2 shows the performance test standards and results of the silver-based solid lubricants.

[0068] Test Project Test standards Test Results Brinell hardness / HB GB / T231.1-2018 63 Yield strength / MPa GB / T7314-2017 196 coefficient of friction GB / T12444-2006 0.13 <![CDATA[Wear rate / × 10 -5 mm 3 / (Nm)]]> GB / T12444-2006 1.9

[0069] Application examples

[0070] The silver-based solid lubricant material described in Example 1 is processed into a solid lubricant block and installed on, as shown in Example 1. Figure 2 In the conductive slip ring shown, the structure of the conductive slip ring (as shown) Figure 2 The device (shown) includes a slip ring 11, a filamentous brush 12, a bracket 13, and a solid lubricant block 14. The filamentous brush 12 and the solid lubricant block are respectively installed on opposite sides of the bracket, and the bracket 13 and the solid lubricant block 14 are in contact with the slip ring 11 and are subjected to a pressure of 20 kPa. The solid lubricant is transferred to the surface of the slip ring 11 by friction between the solid lubricant block 14 and the slip ring 11, forming a conductive solid lubricant film, which provides effective lubrication for the friction pair between the brush 12 and the slip ring 11. The curvature of the friction surface of the solid lubricant block 14 is consistent with the curvature of the slip ring. The conductive slip ring has a life of 58 million revolutions verified on a ground bench test machine (in a vacuum environment).

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silver-based solid lubricant, characterized in that, The raw materials for preparing the silver-based solid lubricant, by weight percentage, include: 74-92% metallic silver, 0.5-1.5% metallic tantalum, 0.5-1.5% metallic titanium, 1.0-4.5% molybdenum disulfide, 1.0-4.5% tungsten disulfide, 1.0-4.5% niobium diselenide, 0.5-1.5% graphite, 1.5-3.5% antimony thioantimonate, 0.5-1.0% lanthanum fluoride, and 1.5-3.5% antimony trioxide.

2. The silver-based solid lubricant material as described in claim 1, characterized in that, The raw materials for preparing the silver-based solid lubricant, by weight percentage, include: 78-88% metallic silver, 1.0-1.5% metallic tantalum, 1.0-1.5% metallic titanium, 2.0-4.5% molybdenum disulfide, 1.0-3.5% tungsten disulfide, 1.0-2.5% niobium diselenide, 0.5-1.0% graphite, 2.0-3.0% antimony thioantimonate, 0.8-1.0% lanthanum fluoride, and 2.0-3.0% antimony trioxide; Furthermore, the sum of the mass percentages of the raw materials used in the preparation of the silver-based solid lubricant is 100%.

3. The method for preparing the silver-based solid lubricant material according to claim 1 or 2, characterized in that, Includes the following steps: Molybdenum disulfide, tungsten disulfide, niobium diselenide, graphite, antimony thioantimonate, lanthanum fluoride, and antimony trioxide were ball-milled to obtain a premixed non-metallic powder. The premixed non-metallic powder, silver, tantalum and titanium are mixed without balls and then hot-pressed and sintered to obtain the silver-based solid lubricant material.

4. The preparation method according to claim 3, characterized in that, The particle size of the molybdenum disulfide, tungsten disulfide, and niobium diselenide is independently 1–10 mm.

5. The preparation method according to claim 3, characterized in that, The graphite has a particle size of 5–25 mm.

6. The preparation method according to claim 3, characterized in that, The particle sizes of antimony thioantimonate, lanthanum fluoride, and antimony trioxide are independently ≤10 mm.

7. The preparation method according to claim 3, characterized in that, The silver is a 200-mesh powder; the tantalum and titanium have particle sizes that are independently <10 mm.

8. The preparation method according to any one of claims 3 to 7, characterized in that, The ball milling mixing time is 4-8 hours, and the mixing time is 2-6 hours.

9. The preparation method according to claim 3, characterized in that, The hot pressing sintering process involves a sintering pressure of 30–80 MPa, a sintering temperature of 650–690 °C, and a holding time of 2–6 h.

10. The application of the silver-based solid lubricant material according to claim 1 or 2 or the silver-based solid lubricant material prepared by the preparation method according to any one of claims 3 to 9 in the lubrication of conductive slip rings.

Images