阅读说明：本技术 一种高温润滑复合材料及其制备方法和应用 (High-temperature lubricating composite material and preparation method and application thereof ) 是由 刘峰 任静姝 王雷 赵文文 曹伟锋 张骁勇 于 2020-05-14 设计创作，主要内容包括：本发明属于高温润滑材料技术领域,提供了一种高温润滑复合材料及其制备方法,所述制备方法包括如下步骤：以质量百分含量计,将如下配比的原料混合：镍38.08～52.64％,铬9.52～13.16％,稳定性氧化锆20.4～28.2％,硫酸锶3～12％和银3～20％,得到固态混合物；将所述固态混合物进行球磨,得到混合粉末；将所述混合粉末进行压制成型,得到成型材料；将所述成型材料进行真空热压烧结,得到所述高温润滑复合材料；所述真空热压烧结的温度为1050～1150℃,压力为20～30MPa,时间为60～120min。本发明提供的高温润滑复合材料在高温下具有较低的摩擦系数和较低的磨损率。(The invention belongs to the technical field of high-temperature lubricating materials, and provides a high-temperature lubricating composite material and a preparation method thereof, wherein the preparation method comprises the following steps: mixing the following raw materials in percentage by mass: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, so as to obtain a solid mixture; ball-milling the solid mixture to obtain mixed powder; performing compression molding on the mixed powder to obtain a molding material; carrying out vacuum hot-pressing sintering on the molding material to obtain the high-temperature lubricating composite material; the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure is 20-30 MPa, and the time is 60-120 min. The high-temperature lubricating composite material provided by the invention has a lower friction coefficient and a lower wear rate at high temperature.)

1. A preparation method of a high-temperature lubricating composite material comprises the following steps:

1) mixing the following raw materials in percentage by mass: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, so as to obtain a solid mixture;

2) ball-milling the solid mixture to obtain mixed powder;

3) performing compression molding on the mixed powder to obtain a molding material;

4) carrying out vacuum hot-pressing sintering on the molding material to obtain the high-temperature lubricating composite material;

the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure is 20-30 MPa, and the time is 60-120 min.

2. The method for preparing a high-temperature lubricating composite material as claimed in claim 1, wherein the absolute pressure of the environment for vacuum hot-pressing sintering is 1.0 × 10^-2～8.0×10^-3Pa。

3. The method for preparing the high-temperature lubricating composite material according to claim 1, wherein the average particle sizes of the nickel, the chromium, the strontium sulfate and the silver are independently 15-74 μm; the stable zirconia has an average particle size of 30 to 50 nm.

4. The preparation method of the high-temperature lubricating composite material according to claim 1, wherein the ball milling is wet ball milling, the dispersion medium of the wet ball milling is ethanol, and the mass ratio of the volume of the dispersion medium to the solid mixture is 2-4 mL: 1-2 g.

5. The preparation method of the high-temperature lubricating composite material according to claim 4, wherein the diameter of the grinding balls for ball milling is 3-10 mm, the rotation speed of the ball milling is 200-450 r/min, the time is 10-30 h, and the ball-to-material ratio of the ball milling is 5-15: 1.

6. The method for preparing a high-temperature lubricating composite material as claimed in claim 4 or 5, wherein the method further comprises the following steps after ball milling: and drying the material obtained by ball milling.

7. The preparation method of the high-temperature lubricating composite material as claimed in claim 6, wherein the drying temperature is 75-85 ℃, and the drying time is 120-240 min.

8. The preparation method of the high-temperature lubricating composite material as claimed in claim 1, wherein the pressure of the compression molding is 5-10 MPa, and the time is 20-40 s.

9. The high-temperature lubricating composite material obtained by the preparation method of any one of claims 1 to 8 comprises strontium zirconate and silver, wherein the mass content of the strontium zirconate is 3.6-14.2%.

10. Use of the high temperature lubricating composite according to claim 9 in the fields of aerospace, oil industry or nuclear technology.

Technical Field

The invention belongs to the technical field of high-temperature lubricating materials, and particularly relates to a high-temperature lubricating composite material and a preparation method and application thereof.

Background

Mechanical moving parts represented by advanced engines are subject to severe working conditions such as high speed, high temperature, heavy load and the like, so that the lubricating material is required to have stable friction coefficient and reliable wear resistance, higher strength, higher oxidation resistance and the like at high temperature. Therefore, the novel high-temperature lubricating composite material designed and prepared by the solid lubricating technology is produced. The high-temperature lubricating composite material is prepared by adding single or multiple solid lubricants and other additional components into a matrix through a certain process method, and has certain mechanical strength and good lubricating property.

In order to improve the high-temperature tribological performance of the high-temperature lubricating composite material, the friction coefficient and the wear rate of the high-temperature lubricating composite material need to be reduced, but the friction coefficient and the wear rate of the existing high-temperature lubricating composite material at high temperature are difficult to be reduced simultaneously. For example, containing Ag/CaF₂/BaF₂The nickel-based composite material has low friction coefficient and wear rate below 600 ℃. However, when the temperature reaches 800 ℃, although the composite material maintains a low friction coefficient, the wear rate is increased sharply and reaches 10 DEG C^-13m³·N^-1·m^-1An order of magnitude.

Disclosure of Invention

The invention provides a high-temperature lubricating composite material and a preparation method and application thereof for solving the problems.

The invention provides a preparation method of a high-temperature lubricating composite material, which comprises the following steps:

1) mixing the following raw materials in percentage by mass: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, so as to obtain a solid mixture;

2) ball-milling the solid mixture to obtain mixed powder;

3) performing compression molding on the mixed powder to obtain a molding material;

4) carrying out vacuum hot-pressing sintering on the molding material to obtain the high-temperature lubricating composite material;

the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure is 20-30 MPa, and the time is 60-120 min.

Preferably, the absolute pressure of the environment for vacuum hot-pressing sintering is 1.0 × 10^-2～8.0×10^-3Pa。

Preferably, the average particle size of the nickel, the chromium, the strontium sulfate and the silver is 15-74 μm independently; the stable zirconia has an average particle size of 30 to 50 nm.

Preferably, the ball milling is wet ball milling, the dispersion medium of the wet ball milling is ethanol, and the mass ratio of the volume of the dispersion medium to the solid mixture is 2-4 mL: 1-2 g.

Preferably, the diameter of the grinding balls used for ball milling is 3-10 mm, the rotating speed of the ball milling is 200-450 r/min, the time is 10-30 h, and the ball-to-material ratio of the ball milling is 5-15: 1.

Preferably, the ball mill further comprises: and drying the material obtained by ball milling.

Preferably, the drying temperature is 75-85 ℃, and the drying time is 120-240 min.

Preferably, the pressure of the compression molding is 5-10 MPa, and the time is 20-40 s.

The invention also provides a high-temperature lubricating composite material obtained by the preparation method in the technical scheme, which comprises strontium zirconate and silver, wherein the mass content of the strontium zirconate is 3.6-14.2%.

The invention also provides the application of the high-temperature lubricating composite material in the technical scheme in the fields of aerospace, petroleum industry or nuclear technology.

The invention provides a preparation method of a high-temperature lubricating composite material, which comprises the following steps: mixing the following raw materials in percentage by mass: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, so as to obtain a solid mixture; ball-milling the solid mixture to obtain mixed powder; performing compression molding on the mixed powder to obtain a molding material; carrying out vacuum hot-pressing sintering on the molding material to obtain the high-temperature lubricating composite material; the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure is 20-30 MPa, and the time is 60-120 min. The nickel, the chromium and the stable zirconia are combined to ensure that the composite material has certain ductility so as to ensure that the material cannot be brittle-broken under high-temperature impact load; according to the invention, strontium sulfate is decomposed through vacuum hot-pressing sintering to obtain strontium oxide, the strontium oxide and stable zirconia form strontium zirconate, and the high-temperature lubricating composite material has a low friction coefficient and a low wear rate at high temperature under the synergistic effect of the strontium zirconate and silver.

Drawings

FIG. 1 is an XRD pattern of a mixed powder and a high-temperature lubricating composite material obtained in examples 2-4; wherein (1), (2) and (3) are XRD patterns of the mixed powders obtained in examples 2, 3 and 4, respectively; (4) and (5) and (6) are XRD patterns of the high-temperature lubricating composite materials obtained in examples 2, 3 and 4, respectively.

Detailed Description

The invention provides a preparation method of a high-temperature lubricating composite material, which comprises the following steps:

1) mixing the following raw materials in percentage by mass: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, so as to obtain a solid mixture;

2) ball-milling the solid mixture to obtain mixed powder;

3) performing compression molding on the mixed powder to obtain a molding material;

4) carrying out vacuum hot-pressing sintering on the molding material to obtain the high-temperature lubricating composite material;

the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure is 20-30 MPa, and the time is 60-120 min.

The invention mixes the following raw materials by mass percentage: 38.08-52.64% of nickel, 9.52-13.16% of chromium, 20.4-28.2% of stable zirconia, 3-12% of strontium sulfate and 3-20% of silver, and obtaining a solid mixture.

In the invention, the raw materials preferably comprise the following components in percentage by mass: 42-50.4% of nickel, 10.5-12.6% of chromium, 22.5-27% of stable zirconia, 5-10% of strontium sulfate and 5-15% of silver. In the present invention, the purities of the nickel, chromium, stabilized zirconia, strontium sulfate, and silver are independently greater than 99%; the average particle size of the nickel is preferably 15-74 μm, more preferably 18-60 μm, and most preferably 40-50 μm; the average particle size of the chromium is preferably 15-74 μm, more preferably 18-55 μm, and most preferably 30-45 μm; the average particle size of the stable zirconia is preferably 30-50 nm, more preferably 35-45 nm, and most preferably 40 nm; the average grain size of the strontium sulfate is preferably 15-74 μm, more preferably 18-65 μm, and most preferably 35-50 μm; the average grain size of the silver is preferably 15-74 μm, more preferably 18-67 μm, and most preferably 28-43 μm. The invention limits the particle sizes of nickel, chromium, stable zirconia, strontium sulfate and silver, is more beneficial to the solid phase reaction in the vacuum hot pressing sintering process, and is beneficial to the reaction of the decomposition product strontium oxide of the strontium sulfate and the stable zirconia to generate strontium zirconate.

In the present invention, the stabilized zirconia preferably comprises one or more of yttria-stabilized zirconia, magnesia-stabilized zirconia, and calcia-stabilized zirconia, and more preferably comprises magnesia-stabilized zirconia or calcia-stabilized zirconia.

In the invention, the strength of the friction layer is reduced and the wear rate of the composite material is increased when the content of silver in the composite material exceeds 20%, and the content of silver less than 3% does not play a role in reducing the friction coefficient. In the invention, strontium oxide formed by decomposing strontium sulfate reacts with stable zirconia to generate strontium zirconate, and the obtained strontium zirconate and silver act synergistically under the condition of the proportion of silver, strontium sulfate and stable zirconia defined in the technical scheme, so that the wear resistance of the composite material is improved.

After obtaining the solid mixture, the invention ball-mills the solid mixture to obtain the mixed powder. In the invention, the ball milling is preferably wet ball milling, the dispersion medium of the wet ball milling is preferably ethanol, and the volume of the dispersion medium and the mass ratio of the solid mixture are preferably 2-4 mL: 1-2 g. In the invention, the grinding balls used for ball milling are preferably alumina balls, and the diameter of the grinding balls is preferably 3-10 mm, and more preferably 5-9 mm; the ball-to-material ratio of the ball milling is preferably 5-15: 1, and more preferably 10: 1; the rotation speed of the ball milling is preferably 200-450 r/min, more preferably 250-400 r/min, and most preferably 350 r/min; the ball milling time is preferably 10-30 h, and more preferably 15-20 h. The invention has no special requirements on equipment used for ball milling, and the embodiment of the invention adopts a planetary high-energy ball mill.

In the present invention, after the ball milling, preferably, the method further comprises drying the material obtained by the ball milling to obtain a mixed powder. In the invention, the drying temperature is preferably 75-85 ℃, and more preferably 77-83 ℃; the drying time is preferably 120-240 min, and more preferably 150-210 min.

The solid mixture is ball-milled, so that nickel, chromium, stable zirconia, strontium sulfate and silver are uniformly mixed, and uniformly mixed powder is obtained. In the invention, nickel and chromium are ball-milled to form a nickel-chromium solid solution, and the nickel-chromium solid solution and the stable zirconia are matched with each other to ensure that the composite material has certain ductility, thereby ensuring that the composite material cannot be brittle under high-temperature impact load.

After the mixed powder is obtained, the mixed powder is pressed and formed to obtain a forming material. In the invention, the pressure of the compression molding is preferably 5-10 MPa, and more preferably 7-9 MPa; the time for the compression molding is preferably 20-40 s, and more preferably 25-35 s; the temperature of the compression molding is preferably 30-50 ℃, more preferably 35-45 ℃, and most preferably 40 ℃. The shape of the molding material is not particularly limited, and the molding material in the embodiment of the present invention is a cylinder, and the diameter of the cylinder is 40 mm.

After a forming material is obtained, the forming material is subjected to vacuum hot-pressing sintering to obtain a high-temperature lubricating composite material, the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, the pressure of the vacuum hot-pressing sintering is 20-30 MPa, and the time of the vacuum hot-pressing sintering is 60-120 min^-2～8.0×10^-3Pa. In the invention, the temperature rise and the vacuum condition of the vacuum hot pressing sintering process are kept consistent.

In the invention, the temperature of the vacuum hot-pressing sintering is 1050-1150 ℃, preferably 1070-1080 ℃; the pressure of the vacuum hot-pressing sintering is 20-30 MPa, preferably 25-28 MPa; the time of the vacuum hot-pressing sintering is 60-120 min, and preferably 85-110 min. The invention has no special requirements on the equipment of vacuum hot-pressing sintering, and the embodiment of the invention adopts a vacuum hot-pressing sintering furnace. The vacuum hot-pressing sintering is carried out within the range of 1050-1150 ℃, and silver in the molding material obtained by pressing the mixed powder can be prevented from being melted and extruded out in the sintering process.

In the process of vacuum hot pressing sintering, strontium sulfate (SrSO)₄) The decomposition generates strontium oxide (SrO) and weak oxidizing gas, the nano-particle stable zirconia with large specific surface area is easy to generate solid phase reaction with the strontium oxide in the sintering process to generate pseudo-cubic strontium zirconate, and nickel and chromium are oxidized to form nickel chromate (NiCr) under the weak oxidizing gas₂O₄). The high-temperature tribological performance of the composite material is improved by the synergistic effect of strontium zirconate and silver. In the invention, nickel and chromium in the composite material are oxidized under the action of high-temperature friction, and the oxidized oxidation products, strontium zirconate and silver are interacted to generate the interacted oxidation products, strontium zirconate and silverUnder the action of frictional stress, the silver generates plastic deformation to form a friction layer with low shear strength, so that the friction coefficient and the wear rate are reduced, and the high-temperature tribology performance of the composite material is obviously improved.

In the present invention, the mold used for the vacuum hot-pressing sintering is preferably a graphite mold.

After the vacuum hot-pressing sintering, the obtained sintering product is preferably cooled to room temperature along with the furnace, so that the high-temperature lubricating composite material is obtained. The invention has no special requirement on the cooling rate of the furnace cooling, and the furnace cooling can be carried out only by cooling to room temperature.

The invention also provides a high-temperature lubricating composite material obtained by the preparation method in the technical scheme, which comprises strontium zirconate and silver, wherein the mass content of the strontium zirconate is 3.6-14.2%. In the present invention, the high temperature lubricating composite material contains phases further comprising ni (cr) solid solution, stabilized zirconia and nickel chromate; in the embodiment of the present invention, the content of the strontium zirconate in the composite material is preferably 6 to 11.9% by mass.

The invention also provides the application of the high-temperature lubricating composite material in the technical scheme in the fields of aerospace, petroleum industry or nuclear technology.

With the development of modern industry, a plurality of sliding parts which need to work under extreme environments (such as high temperature, high speed and high load) exist in the fields of aerospace, oil industry and nuclear technology, the high-temperature lubricating composite material provided by the invention has high wear resistance at high temperature, and can be used for sliding parts which work under high temperature, high speed and high load conditions, such as turbine engine intake valve ejector pin lubrication, guide sleeves, shaft sleeves, blades of rotors and stators and the like.

In order to further illustrate the present invention, a high temperature lubricating composite material and its application provided by the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.