Self-lubricating composite powder, self-lubricating composite material and preparation method and application thereof

Abstract

The application provides a self-lubricating composite powder, a self-lubricating composite material and a preparation method and application thereof, the self-lubricating composite powder is composed of NiCr, Cr3C2 and LaF3; the preparation method of the self-lubricating composite powder comprises the following steps: mixing raw materials and ball milling under a protective atmosphere; and the self-lubricating composite material is prepared by hot-pressing sintering through the self-lubricating composite powder. The self-lubricating composite powder provided by the application can form a single structure, has uniform composition and particle size, and can regulate the content of components, and has good effects on the preparation of the self-lubricating composite material; the self-lubricating composite material provided by the application has a compact structure, uniform composition and excellent mechanical properties, has high hardness, few defects, and uniform distribution of ceramic reinforcing phases and lubricating phases, has a low friction coefficient and good wear resistance; the preparation method is simple, the preparation cost is low, and the success rate is high.

Description

Technical Field

[0001] This invention belongs to the field of self-lubricating materials technology, and relates to a self-lubricating composite material, specifically a self-lubricating composite powder, a self-lubricating composite material, its preparation method and application. Background Technology

[0002] Solid lubricants can be used in harsh working environments with high temperatures where lubricating greases cannot be used, playing a crucial role in reducing energy loss and extending component life in mechanical components. With the continuous development of high-end equipment and cutting-edge industries, the energy density of friction surfaces is increasing dramatically, leading to a significant rise in temperature. Solid self-lubricating materials need to meet even higher operating temperatures. Simultaneously, to reduce friction loss and extend service life, the materials must possess good wear resistance. Therefore, the development of high-temperature wear-resistant self-lubricating materials has significant strategic value.

[0003] CN102965596A discloses a Fe-Ni-Cr high-temperature self-lubricating composite material with added NbSe2 and its preparation method. This composite material uses iron as the matrix, nickel and chromium as reinforcing alloying elements, and calcium fluoride, niobium diselenide and graphite composite as the lubricating phase. It is prepared by powder metallurgy and has good self-lubricating properties and excellent wear resistance at 550-750℃.

[0004] CN110965058A discloses a NiCr / Cr3C2 / WS2 self-lubricating wear-resistant coating. This coating is prepared using laser cladding technology and contains Cr7C3, (Cr,W)C carbide reinforcing phase, γ-(Fe,Ni) / Cr7C3 eutectic toughening phase, WS2 and CrS lubricating phase, which improves the hardness and wear resistance of the substrate.

[0005] CN113308690A discloses a self-lubricating wear-resistant coating for engine bearings and its preparation method. The coating consists of TiC, NiCr and functional powders, and is prepared by a high-laser coating method. The coating has high density, good adhesion to the substrate, and good wear resistance.

[0006] In the existing technology, self-lubricating materials have many additive phase components, which can easily lead to uneven composition. The preparation method is complicated and has high requirements for preparation conditions and technology. In addition, the wear resistance of the material at high temperature needs to be further improved.

[0007] Therefore, to address the shortcomings of existing technologies, there is a need to provide a self-lubricating composite powder, a self-lubricating composite material, its preparation method, and its application. Summary of the Invention

[0008] The purpose of this invention is to provide a self-lubricating composite powder, a self-lubricating composite material, and their preparation methods and applications. The composite powder and composite material have uniform composition and good high-temperature wear resistance.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a self-lubricating composite powder, wherein the self-lubricating composite powder is composed of NiCr, Cr3C2 and LaF3;

[0011] The self-lubricating composite powder contains 5-20 wt% LaF3.

[0012] The self-lubricating composite powder provided by this invention has uniform composition and consistent particle size, and can form a single structure. NiCr exhibits good oxidation resistance, a low coefficient of friction, and good mechanical properties at higher temperatures. Introducing Cr3C2 significantly improves its wear resistance and hardness. Simultaneously, the addition of LaF3 lubricating phase reduces the coefficient of friction and improves friction performance. LaF3 possesses good lubrication properties and thermal stability; its introduction increases the overall quality of the ceramic phase. Using a NiCr alloy to bind the components further enhances lubrication performance and hardness, resulting in excellent performance for preparing composite materials.

[0013] The self-lubricating composite powder contains 5-20 wt% LaF3, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, or 20 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, in the self-lubricating composite powder, the mass ratio of NiCr to Cr3C2 is 1:(1-3), for example, it can be 1:1, 1:1.5, 1:2, 1:2.5 or 1:3, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] In a second aspect, the present invention provides a method for preparing the self-lubricating composite powder as described in the first aspect, the method comprising the following steps:

[0016] Ni raw material, Cr raw material, Cr3C2 raw material and LaF3 raw material are mixed to obtain raw material mixture, and the raw material mixture is ball-milled under a protective atmosphere.

[0017] The composite powder preparation method provided by this invention can prepare composite powder with uniform composition, controllable particle size, and good sintering performance. Furthermore, when the composite powder is applied to the preparation of self-lubricating composite materials, it can effectively reduce the loss of LaF3 during the hot pressing process.

[0018] During the ball milling process, Ni and Cr are mixed to form a NiCr alloy. The amount of Ni, Cr, Cr3C2 and LaF3 raw materials added is such that the content of LaF3 is 5-20wt%, and the mass ratio of NiCr to Cr3C2 is 1:(1-3).

[0019] Preferably, the purity of the Ni raw material, Cr raw material, Cr3C2 raw material and LaF3 raw material is ≥99%, for example, it can be 99%, 99.2%, 99.4%, 99.5%, 99.6%, 99.8% or 99.9%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the particle size of the Ni raw material, Cr raw material, Cr3C2 raw material and LaF3 raw material is ≤325 mesh, for example, it can be 325 mesh, 350 mesh, 500 mesh, 700 mesh or 1000 mesh, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0021] Preferably, the rotational speed of the ball mill is 100-400 r / min, for example, it can be 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min or 400 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, the ball-to-material mass ratio of the ball mill is (1-15):1, for example, it can be 1:1, 5:1, 8:1, 10:1, 12:1 or 15:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, the ball milling time is 2-48 hours, for example, it can be 2 hours, 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours or 48 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] Preferably, the protective atmosphere includes any one or a combination of at least two of nitrogen, helium, argon, or neon. Typical but non-limiting combinations include combinations of nitrogen and helium, argon and neon, nitrogen, helium, and argon, helium, argon, and neon, or nitrogen, helium, argon, and neon.

[0025] Preferably, the ball milling is followed by filtration and vacuum drying.

[0026] Preferably, the vacuum drying temperature is 60-150℃, for example, it can be 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0027] Preferably, the vacuum drying time is 2-8 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Thirdly, the present invention provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder described in the first aspect.

[0029] The self-lubricating composite material provided by this invention has a dense structure, uniform composition, high hardness, few defects, and uniform distribution of ceramic reinforcing phase and lubricating phase, resulting in a low coefficient of friction and good wear resistance.

[0030] Fourthly, the present invention provides a method for preparing a self-lubricating composite material as described in the third aspect, the method comprising the following steps:

[0031] The self-lubricating composite powder was hot-pressed and sintered.

[0032] Preferably, the heating rate of the hot pressing sintering is 50-100℃ / min, for example, it can be 50℃ / min, 60℃ / min, 70℃ / min, 80℃ / min, 90℃ / min or 100℃ / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0033] Preferably, the hot pressing sintering temperature is 1000-1200℃, for example, it can be 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] Preferably, the hot pressing sintering pressure is 30-50 MPa, for example, it can be 30 MPa, 35 MPa, 40 MPa, 45 MPa or 50 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0035] Preferably, the hot pressing sintering time is 5-30 min, for example, it can be 5 min, 10 min, 15 min, 20 min, 25 min or 30 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Fifthly, the present invention provides an application of the self-lubricating composite material as described in the third aspect, wherein the self-lubricating composite material is used in brush seals in aero engines and / or gas turbines.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The self-lubricating composite powder provided by this invention can form a single structure with uniform composition and consistent particle size, and the composition content can be controlled, making it effective for preparing self-lubricating composite materials. The self-lubricating composite material provided by this invention has a dense structure, uniform composition, and excellent mechanical properties, with high hardness, few defects, and uniform distribution of ceramic reinforcing phase and lubricating phase, resulting in a low coefficient of friction and good wear resistance. Its preparation method is simple, with low preparation cost and high success rate. Attached Figure Description

[0039] Figure 1 This is a scanning electron microscope image of the self-lubricating composite powder prepared in Preparation Example 1.

[0040] Figure 2 This is the XRD pattern of the self-lubricating composite powder prepared in Example 1.

[0041] Figure 3 This is a scanning electron micrograph of the self-lubricating composite material prepared in Example 1.

[0042] Figure 4 This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 1.

[0043] Figure 5 This is a scanning electron microscope image of the self-lubricating composite powder prepared in Preparation Example 2.

[0044] Figure 6 This is a scanning electron micrograph of the self-lubricating composite material prepared in Example 2.

[0045] Figure 7 This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 2.

[0046] Figure 8 This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 3.

[0047] Figure 9 This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 4.

[0048] Figure 10 This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 5.

[0049] Figure 11This is a three-dimensional image of the wear marks after friction of the self-lubricating composite material prepared in Example 6. Detailed Implementation

[0050] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0051] To clearly illustrate the technical solution of the present invention, scanning electron micrographs of the self-lubricating composite powder and self-lubricating composite material prepared in the preparation examples and embodiments were taken using a Zeiss Gemini 300 scanning electron microscope (UK); the friction properties of the self-lubricating composite material prepared in the embodiments were tested using a China Zhongke Kaihua HT-1000 high-temperature friction and wear tester; and the three-dimensional morphology of the wear tracks after friction of the self-lubricating composite material prepared in the embodiments was taken using a ZYGO nexview white light confocal microscope (USA).

[0052] In the embodiments of the present invention, the hot pressing sintering for preparing the self-lubricating composite material was carried out using the FMP-888 rapid hot pressing sintering furnace of Hatten Technology Co., Ltd.

[0053] Preparation Example 1

[0054] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:3 and the content of LaF3 is 15wt%.

[0055] The method for preparing the self-lubricating powder includes the following steps:

[0056] (1) Ni, Cr, Cr3C2 and LaF3 raw materials were mixed evenly, wherein the mass ratio of Ni, Cr and Cr3C2 was 4:1:15, the purity of the four raw material powders was 99% and the particle size was ≤325 mesh. Under the protection of argon, the raw material mixture was ball-milled at 300 r / min for 15 h. During ball milling, the mass ratio of ball to material was 10:1. Zirconia balls with sizes of 10 mm, 5 mm and 3 mm were used in a nylon tank at a mass ratio of 5:10:5.

[0057] (2) The product obtained in step (1) is taken out and filtered, and then vacuum dried at 80°C for 2 hours to obtain self-lubricating composite powder.

[0058] The scanning electron microscope image of the self-lubricating composite powder prepared in this example is shown below. Figure 1 As shown, the XRD pattern is as follows Figure 2 As shown.

[0059] The microstructure of the self-lubricating composite powder prepared in this example is as follows: Figure 1 As shown, the composite powder is relatively uniformly dispersed, with a diameter of less than 10 μm. The small particle size promotes sintering. XRD phase analysis of the composite powder using an X-ray diffractometer shows that the phase of the composite powder is consistent with the designed composition.

[0060] Preparation Example 2

[0061] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:1.5 and the content of LaF3 is 10wt%.

[0062] The method for preparing the self-lubricating powder includes the following steps:

[0063] (1) Ni, Cr, Cr3C2 and LaF3 raw materials were mixed evenly, wherein the mass ratio of Ni, Cr and Cr3C2 was 4:1:7.5, the purity of the four raw material powders was 99%, and the particle size was ≤325 mesh. Under the protection of argon, the raw material mixture was ball-milled at 300 r / min for 48 h. During ball milling, the mass ratio of ball to material was 5:1. Zirconia balls with sizes of 10 mm, 5 mm and 3 mm were used in a nylon tank at a mass ratio of 5:10:5.

[0064] (2) The product obtained in step (1) is taken out and filtered, and then vacuum dried at 80°C for 2 hours to obtain self-lubricating composite powder.

[0065] The scanning electron microscope image of the self-lubricating composite powder prepared in this example is shown below. Figure 5 As shown.

[0066] The microstructure of the self-lubricating composite powder prepared in this example is as follows: Figure 5 As shown, the composite powder is relatively uniformly dispersed, with a powder diameter of less than 10 μm. The small particle size promotes sintering. XRD phase analysis of the composite powder using an X-ray diffractometer shows that the phase of the composite powder is consistent with the designed composition.

[0067] Preparation Example 3

[0068] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:3 and the content of LaF3 is 20wt%.

[0069] The method for preparing the self-lubricating powder includes the following steps:

[0070] (1) Ni, Cr, Cr3C2 and LaF3 raw materials were mixed evenly, wherein the mass ratio of Ni, Cr and Cr3C2 was 3:1:12, the purity of the four raw material powders was 99% and the particle size was ≤325 mesh. Under the protection of argon, the raw material mixture was ball-milled at 100 r / min for 48 h. During ball milling, the mass ratio of ball to material was 1:1. Zirconia balls with sizes of 10 mm, 5 mm and 3 mm were used in a nylon tank at a mass ratio of 5:10:5.

[0071] (2) The product obtained in step (1) is taken out and filtered, and then vacuum dried at 60°C for 8 hours to obtain self-lubricating composite powder.

[0072] Preparation Example 4

[0073] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:1 and the content of LaF3 is 5wt%.

[0074] The method for preparing the self-lubricating powder includes the following steps:

[0075] (1) Ni, Cr, Cr3C2 and LaF3 raw materials were mixed evenly, wherein the mass ratio of Ni, Cr and Cr3C2 was 4:1:5, the purity of the four raw material powders was 99% and the particle size was 325 mesh. Under the protection of argon, the raw material mixture was ball-milled at 200 r / min for 2 h. During ball milling, the mass ratio of ball to material was 15:1. Zirconia balls with sizes of 10 mm, 5 mm and 3 mm were used in a nylon tank at a mass ratio of 5:10:5.

[0076] (2) The product obtained in step (1) is taken out and filtered, and then vacuum dried at 150°C for 5 hours to obtain self-lubricating composite powder.

[0077] Preparation Example 5

[0078] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:0.5 and the content of LaF3 is 15wt%.

[0079] The preparation method of the self-lubricating composite powder is the same as that in Preparation Example 1.

[0080] Preparation Example 6

[0081] This preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:4 and the content of LaF3 is 15wt%.

[0082] The preparation method of the self-lubricating composite powder is the same as that in Preparation Example 1.

[0083] Comparative Preparation Example 1

[0084] This comparative preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:3 and the content of LaF3 is 2.5 wt%.

[0085] The preparation method of the self-lubricating composite powder is the same as that in Preparation Example 1.

[0086] Comparative Preparation Example 2

[0087] This comparative preparation example provides a self-lubricating composite powder, the composition of which is NiCr, Cr3C2 and LaF3, wherein the mass ratio of NiCr to Cr3C2 is 1:3 and the content of LaF3 is 25wt%.

[0088] The preparation method of the self-lubricating composite powder is the same as that in Preparation Example 1.

[0089] Comparative preparation example 3

[0090] This comparative preparation example provides a self-lubricating composite powder, the composition of which is NiCr and Cr3C2, wherein the mass ratio of NiCr to Cr3C2 is 1:3.

[0091] The preparation method of the self-lubricating composite powder is the same as that in Preparation Example 1.

[0092] Example 1

[0093] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 1.

[0094] The preparation method of the self-lubricating composite material includes the following steps:

[0095] The self-lubricating composite powder was hot-pressed and sintered, with the temperature increased to 1100℃ at a rate of 100℃ / min and the pressure increased to 50MPa. The temperature and pressure were then maintained for 5 minutes to obtain the self-lubricating composite material.

[0096] The scanning electron micrograph of the self-lubricating composite material prepared in this embodiment is shown below. Figure 3 As shown, the 3D image of the wear marks is as follows: Figure 4 As shown.

[0097] The microstructure of the self-lubricating composite material prepared in this embodiment is as follows: Figure 3 As shown, the composite material is mainly composed of a ceramic-rich phase formed by sintering Cr3C2 and LaF3, which gives it both high hardness and good self-lubricating properties. The NiCr alloy phase is distributed in a dotted pattern within the matrix, filling the material's pores and providing good antioxidant protection. The composite material has a dense structure with few defects, and the added LaF3 is evenly distributed. The wear marks after friction at 800℃ were observed using a white light interference microscope. Figure 4 As shown, the wear tracks of the composite material after friction are shallow and narrow, with very little wear loss, indicating excellent wear resistance.

[0098] Example 2

[0099] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 2.

[0100] The preparation method of the self-lubricating composite material includes the following steps:

[0101] The self-lubricating composite powder was hot-pressed and sintered, with the temperature increased to 1100℃ at a rate of 50℃ / min and the pressure increased to 30MPa. The temperature and pressure were maintained for 15 minutes to obtain the self-lubricating composite material.

[0102] The scanning electron micrograph of the self-lubricating composite material prepared in this embodiment is shown below. Figure 6 As shown, the 3D image of the wear marks is as follows: Figure 7 As shown.

[0103] The microstructure of the self-lubricating composite material prepared in this embodiment is as follows: Figure 6 As shown, the composite material has a dense structure with few defects, and the added LaF3 is evenly distributed. The wear marks after friction at 800℃ were observed using a white light interference microscope. Figure 7 As shown, the wear tracks of the composite material after friction are shallow and narrow, with very little wear loss, indicating excellent wear resistance.

[0104] Example 3

[0105] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 3.

[0106] The preparation method of the self-lubricating composite material includes the following steps:

[0107] The self-lubricating composite powder was hot-pressed and sintered, with the temperature increased to 1000℃ at a rate of 80℃ / min and the pressure at 40MPa, and the temperature and pressure were held for 5 minutes to obtain the self-lubricating composite material.

[0108] The wear track 3D image of the self-lubricating composite material prepared in this embodiment is shown below. Figure 8 As shown.

[0109] Example 4

[0110] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 4.

[0111] The preparation method of the self-lubricating composite material includes the following steps:

[0112] The self-lubricating composite powder was hot-pressed and sintered, with the temperature increased to 1200℃ at a rate of 100℃ / min and the pressure at 30MPa, and the temperature and pressure were held for 30min to obtain the self-lubricating composite material.

[0113] The wear track 3D image of the self-lubricating composite material prepared in this embodiment is shown below. Figure 9 As shown.

[0114] Example 5

[0115] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 5.

[0116] The preparation method of the self-lubricating composite material is the same as that in Example 1.

[0117] The wear track 3D image of the self-lubricating composite material prepared in this embodiment is shown below. Figure 10 As shown.

[0118] Example 6

[0119] This embodiment provides a self-lubricating composite material, which is prepared from the self-lubricating composite powder prepared in Preparation Example 6.

[0120] The preparation method of the self-lubricating composite material is the same as that in Example 1.

[0121] The wear track 3D image of the self-lubricating composite material prepared in this embodiment is shown below. Figure 11 As shown.

[0122] Example 7

[0123] This embodiment provides a self-lubricating composite material, the composition of which is the same as that in Embodiment 1.

[0124] The preparation method of the self-lubricating composite material is the same as that of Example 1, except that the hot pressing sintering temperature is 900℃.

[0125] Example 8

[0126] This embodiment provides a self-lubricating composite material, the composition of which is the same as that in Embodiment 1.

[0127] The preparation method of the self-lubricating composite material is the same as that of Example 1, except that the hot pressing sintering temperature is 1300℃.

[0128] Scanning electron microscopy was used to analyze the morphology of the composite material prepared in this embodiment. The results showed that the LaF3 ceramic phase was unevenly distributed and the composition was lost. Analysis using a high-temperature friction and wear tester showed that the friction coefficient of the prepared composite material was high at all temperatures and showed a trend of increasing with increasing temperature. Analysis of the wear tracks using white light interference microscopy showed that the wear tracks were deep and wide, with a large volume wear rate and poor wear resistance.

[0129] Example 9

[0130] This embodiment provides a self-lubricating composite material, the composition of which is the same as that in Embodiment 1.

[0131] The preparation method of the self-lubricating composite material is the same as that of Example 1, except that the hot pressing sintering pressure is 20 MPa.

[0132] Example 10

[0133] This embodiment provides a self-lubricating composite material, the composition of which is the same as that in Embodiment 1.

[0134] The preparation method of the self-lubricating composite material is the same as that of Example 1, except that the hot pressing sintering pressure is 60 MPa.

[0135] Comparative Example 1

[0136] This comparative example provides a self-lubricating composite material prepared from the self-lubricating composite powder prepared in Comparative Preparation Example 1.

[0137] The preparation method of the self-lubricating composite material is the same as that in Example 1.

[0138] XRD phase analysis of the self-lubricating composite powder prepared in this comparative example was performed using an X-ray diffractometer. The results showed that the LaF3 diffraction peaks were not obvious. The microstructure of the self-lubricating composite material was observed using a scanning electron microscope. The results showed that the LaF3 distribution was uneven. Analysis using a high-temperature friction and wear tester showed that the friction coefficient of the prepared composite material was high at all temperatures and showed a trend of continuous increase with increasing temperature. Analysis of the wear tracks using a white light interference microscope showed that the wear tracks were deep and wide, with a large volumetric wear rate and poor wear resistance.

[0139] Comparative Example 2

[0140] This comparative example provides a self-lubricating composite material prepared from the self-lubricating composite powder prepared in Comparative Preparation Example 2.

[0141] The preparation method of the self-lubricating composite material is the same as that in Example 1.

[0142] Comparative Example 3

[0143] This comparative example provides a self-lubricating composite material prepared from the self-lubricating composite powder prepared in Comparative Preparation Example 3.

[0144] The preparation method of the self-lubricating composite material is the same as that in Example 1.

[0145] Table 1

[0146]

[0147] As can be seen from Table 1:

[0148] The self-lubricating composite material provided by this invention has a low coefficient of friction from room temperature to 800°C, with a minimum of 0.32 at high temperatures. It also has a very low volumetric wear loss, combining good self-lubricating properties at both room temperature and high temperature with good wear resistance.

[0149] Compared with Example 1, Examples 5 and 6 added Cr3C2 content exceeding the preferred content of the present invention, which affected the overall hardness and wear resistance of the material and increased its volumetric wear loss. In Examples 7-10, when the hot pressing sintering parameters exceeded the preferred content of the present invention, the hot pressing sintering process was prone to material composition loss or uneven phase distribution, which in turn caused a significant decrease in its performance.

[0150] In Comparative Examples 1 and 3, when the content of LaF3 is too low or no LaF3 is added, the material lacks a lubricating phase, and its friction coefficient increases significantly at all temperatures, making it difficult to meet the requirements for self-lubricating materials. In Comparative Example 2, when too much LaF3 is added, the wear resistance decreases significantly due to the relatively insufficient content of the wear-resistant phase. Therefore, when an inappropriate amount of LaF3 is added to the material, it is difficult to achieve both good self-lubrication and wear resistance.

[0151] In summary, the self-lubricating composite powder provided by this invention can form a single structure with uniform composition and consistent particle size, and the composition content can be controlled, making it effective for preparing self-lubricating composite materials. The self-lubricating composite material provided by this invention has a dense structure, uniform composition, and excellent mechanical properties, with high hardness, few defects, and uniform distribution of ceramic reinforcing phase and lubricating phase, resulting in a low coefficient of friction and good wear resistance. Its preparation method is simple, with low preparation cost and high success rate.

[0152] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A self-lubricating composite material, characterized in that, The self-lubricating composite material is prepared from self-lubricating composite powder; The self-lubricating composite powder is composed of NiCr, Cr3C2 and LaF3; The self-lubricating composite powder contains 5-20 wt% LaF3 and the mass ratio of NiCr to Cr3C2 is 1:(1-3). The preparation method of the self-lubricating composite powder includes the following steps: mixing Ni raw material, Cr raw material, Cr3C2 raw material and LaF3 raw material to obtain a raw material mixture, and ball milling the raw material mixture under a protective atmosphere; The self-lubricating composite material is prepared by the following method, the method comprising: The self-lubricating composite powder was hot-pressed and sintered at 1000-1200℃ and 30-50MPa.

2. The self-lubricating composite material according to claim 1, characterized in that, The purity of the Ni, Cr, Cr3C2, and LaF3 raw materials is ≥99%.

3. The self-lubricating composite material according to claim 1, characterized in that, The particle size of the Ni, Cr, Cr3C2, and LaF3 raw materials is ≤325 mesh.

4. The self-lubricating composite material according to claim 1, characterized in that, The ball mill rotates at a speed of 100-400 r / min.

5. The self-lubricating composite material according to claim 1, characterized in that, The ball-to-material mass ratio of the ball mill is (1-15):

1.

6. The self-lubricating composite material according to claim 1, characterized in that, The ball milling time is 2-48 hours.

7. The self-lubricating composite material according to claim 1, characterized in that, The protective atmosphere includes any one or a combination of at least two of nitrogen, helium, argon, or neon.

8. The self-lubricating composite material according to claim 1, characterized in that, After ball milling, the material is sequentially filtered and vacuum dried.

9. The self-lubricating composite material according to claim 8, characterized in that, The vacuum drying temperature is 60-150℃.

10. The self-lubricating composite material according to claim 8, characterized in that, The vacuum drying time is 2-8 hours.

11. A method for preparing a self-lubricating composite material as described in any one of claims 1-10, characterized in that, The preparation method includes the following steps: The self-lubricating composite powder is hot-pressed and sintered at 1000-1200℃ and 30-50MPa.

12. The preparation method according to claim 11, characterized in that, The heating rate of the hot pressing sintering is 50-100℃ / min.

13. The preparation method according to claim 11, characterized in that, The hot pressing and sintering time is 5-30 minutes.

14. The application of a self-lubricating composite material as described in any one of claims 1-10, characterized in that, The self-lubricating composite material is used in brush seals for aero engines and / or gas turbines.

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