Corrosion-resistant high-strength high-toughness metal-based self-lubricating composite material and preparation and application thereof

Abstract

The application belongs to the technical field of corrosion resistance and self-lubrication, and particularly relates to a corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material and preparation and application thereof. The composite material is composed of a metal matrix phase, a metal reinforcing phase, a metal self-lubricating phase and a ceramic self-lubricating phase. The metal matrix phase is nickel, cobalt, nickel-chromium alloy or cobalt-chromium alloy. The metal reinforcing phase is any one or more than two combinations of molybdenum, tungsten, tantalum and niobium. The self-lubricating phase is silver, tungsten disulfide and molybdenum disulfide. The application controls the interface reaction between the self-lubricating phase and the metal matrix phase by special material composition and network structure design, forms interface chemical combination or metallurgical combination, and promotes solid solution of the metal reinforcing phase, fully plays the advantages of high strength and high toughness of the metal matrix phase and the friction-reducing and wear-resistant advantages of the self-lubricating phase, and the prepared composite material has excellent corrosion resistance, high strength, high toughness and self-lubricating comprehensive performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of corrosion resistance and self-lubrication, and particularly relates to a corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material and its preparation and application, which can be used for joint bearings, shaft sleeves, bushings and other transmission and moving parts serving in marine or atmospheric corrosion environments in the fields of aviation, aerospace, energy and chemical industry, and meets the requirements of bushing cold shrinkage or press-fit assembly scheme. BACKGROUND

[0002] A typical feature of marine environment corrosion is that there are extremely corrosive chloride ions in seawater or salt mist, which can easily destroy the passivation film on the surface of the material. At the same time, the fatigue cracks generated in the subsurface during friction also accelerate the peeling and degradation of the surface passivation film.

[0003] A. Lopez (Wear 338-339 (2015) 1-10) reported that the wear amount of a high-strength steel for marine use in simulated seawater was 2.1 times the simple sum of single seawater corrosion wear and single wear, and solid-state self-lubrication is the most effective solution for reducing friction and wear of moving parts. Because of the low shear strength of solid-state self-lubricating materials, the transfer between the counter-surfaces can be easily completed during friction, so that the friction finally occurs only between the two self-lubricating film layers, greatly reducing the friction coefficient and wear amount, and protecting the transmission parts and main load-bearing parts (moving parts) at the same time.

[0004] Chinese patent (publication number CN107177758A) proposes a high-temperature-resistant and oxidation-resistant metal-based self-lubricating composite material and its preparation method. The composite material is composed of high-aluminum nickel-based alloy as the matrix, calcium fluoride / barium fluoride eutectic and enamel as the self-lubricating phase, aluminum oxide as the hard phase, and rare earth oxides such as cerium dioxide and yttrium trioxide as the antioxidant, which are prepared by spark plasma sintering. Among them, according to the weight percentage, the high-aluminum nickel-based alloy is 65% to 82%, the self-lubricating phase is 8% to 15% (of which calcium fluoride / barium fluoride eutectic is ≤10%, enamel is 3-10%), aluminum trioxide is 6-15%, and antioxidant is 2-10%. Through the design of high-aluminum nickel-based alloy, the addition of antioxidant and new high-temperature self-lubricating phase enamel, the composite material has the properties of high-temperature resistance, oxidation resistance and excellent self-lubricating comprehensive performance, and can be used for the production of parts in oxidation-resistant, high-temperature-resistant and self-lubricating environments. However, the self-lubricating composite material prepared by this method contains a large amount of ceramic lubricating phase (such as fluoride and enamel 8-15%) and ceramic particles (aluminum trioxide 6-15%), which results in very low toughness and plasticity, and cannot meet the processing requirements of complex parts, not to mention the cold shrinkage and press-fit assembly requirements of self-lubricating bushings.

[0005] For some key transmission components which are not suitable for grease lubrication and are facing the salt spray and seawater corrosion in marine environment, simple alloy materials cannot adapt to such complex and harsh service environment, and new corrosion-resistant composite materials with self-lubricating function are urgently needed. The fields involved include deep-sea oilfield exploitation, offshore power, ships, aircraft, etc. SUMMARY

[0006] The present application aims to provide a corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material and its preparation and application. The metal-based composite material prepared by designing the grain size of the composite material, the matching ratio and size of the self-lubricating phase, etc. breaks through the traditional cognition that the self-lubricating performance, strength and toughness, and corrosion resistance of the material are contradictory. In the preparation process, the interface reaction between the metal matrix and the self-lubricating phase is controlled by using the spark plasma sintering method to improve the interface bonding strength and reduce the porosity, so as to realize the optimization of the mechanical properties. The prepared composite material has excellent comprehensive properties such as corrosion resistance, high strength, high toughness and self-lubrication.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material, the composition of the composite material is as follows in terms of weight percentage:

[0009]

[0010] Among them, the metal matrix phase is nickel, cobalt, nickel-chromium alloy or cobalt-chromium alloy, the original powder particle size of the metal matrix phase used for preparing the composite material is 30-70 μm; the metal reinforcing phase is any one or more than two combinations of molybdenum, tungsten, tantalum and niobium, the original powder particle size of the metal reinforcing phase used for preparing the composite material is ≤20 μm; the metal self-lubricating phase is silver or copper-silver alloy, the ceramic self-lubricating phase is tungsten disulfide and molybdenum disulfide, and the weight percentage of molybdenum disulfide in the composite material is ≤2%; the original powder of the metal self-lubricating phase and the ceramic self-lubricating phase used for preparing the composite material is sub-micron size, and the powder particle size is ≤2 μm.

[0011] The corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material has a network-like microstructure, a defect-free surface, and the metal self-lubricating phase and the ceramic self-lubricating phase are dispersedly distributed in the metal matrix phase and chemically combined with the matrix interface, and part or all of the metal reinforcing phase is solid-solved in the metal matrix phase.

[0012] The corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material has the following properties after seawater or salt spray corrosion: the density is ≥98.0%, the corrosion resistance level is better than 2 levels, the neutral salt spray corrosion life is ≥500 h, the compressive strength is ≥1200 MPa, and the compression deformation rate is ≥25%.

[0013] The preparation method of the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material comprises the following steps:

[0014] (1) Powder mixing: according to the component proportion of the composite material, the metal matrix phase powder, the metal reinforcing phase powder, the metal self-lubricating phase powder and the ceramic self-lubricating phase powder are mixed by a planetary ball mill at a rotating speed of 280-320 rpm for 10-15 hours to obtain uniformly mixed composite powder;

[0015] (2) Vacuum discharge plasma sintering: the composite powder obtained in step (1) is subjected to vacuum discharge plasma sintering to obtain the metal-based self-lubricating composite material.

[0016] The preparation method of the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material, and the process parameters of the vacuum discharge plasma sintering are as follows:

[0017] Vacuum degree < 1 x 10 -2 atm;

[0018] Sintering temperature: 1000-1100 DEG C;

[0019] Heating rate: 50-100 DEG C / min;

[0020] Sintering pressure: 20-30 MPa;

[0021] Soaking time: 10-20 min, and natural cooling after soaking.

[0022] The application of the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material, and the composite material is applied to the preparation of bushings, joint bearings or shaft parts of marine environment oilfield exploitation, offshore power, ships and aircraft equipment, and is suitable for cold shrinkage and press-fit assembly of bushings.

[0023] The design principle and beneficial effects of the present application are as follows:

[0024] 1. The existing ordinary composite material cannot have high strength, high toughness and self-lubricating performance, the present application combines the metal self-lubricating phase with the ceramic self-lubricating phase, the introduction of a large amount of ceramic self-lubricating phase inevitably reduces the fracture toughness of the composite material, and the low shear strength of the soft metal (self-lubricating phase) reduces the yield strength of the composite material, so that the composite material is difficult to realize the synergistic optimization of mechanical properties and friction and wear properties. The composite material provided by the present application has high strength, good toughness, and low friction coefficient and wear rate. The friction coefficient of the composite material is ≤0.25, the wear rate is ≤3 x 10 -5 mm 3 / (N.m), the compressive strength is ≥1200 MPa, and the compression deformation rate is ≥25%.

[0025] 2. Conventional self-lubricating composite materials cannot simultaneously achieve both corrosion resistance and self-lubrication properties. Friction and wear easily destroy the passivation film generated during the corrosion process, thereby accelerating corrosion; while corrosion increases the brittleness of the material surface, inducing the initiation and propagation of subsurface cracks during friction, thus accelerating wear. The composite material provided by this invention exhibits low friction coefficient and wear rate, low corrosion rate, and the overall material consumption under the interaction of corrosion and wear is less than the simple sum of single corrosion and single wear in a seawater environment. The relative density of this composite material in seawater or after salt spray corrosion is ≥98.0%, the corrosion resistance level is better than level 2, the neutral salt spray corrosion life is ≥500h, the friction coefficient is ≤0.25, and the wear rate is ≤3×10. - 5 mm 3 / (Nm).

[0026] 3. Spark plasma sintering (SPS) offers rapid heating, enabling the preparation of high-density nanoscale composite materials with controllable microstructure, thereby optimizing the material's mechanical and tribological properties. Due to its unique heating method, the self-lubricating phase is prone to decomposition or interfacial reaction with the alloy matrix during heating, thus impairing the self-lubricating properties of the composite material. This invention utilizes a dual self-lubricating agent, a soft metal silver (or copper-silver alloy), combined with sulfides (tungsten disulfide, molybdenum disulfide). The high affinity between sulfides and silver weakens the reaction between the sulfides and the alloy matrix, promoting the dissolution and even nano-sized dissolution of submicron silver particles, forming an interfacial chemical or metallurgical bond with the alloy matrix. This ensures the composite material's mechanical properties while improving the high-temperature stability of the self-lubricating phase, achieving dual optimization of both mechanical and self-lubricating properties.

[0027] 4. The corrosion-resistant, high-strength, and high-toughness metal-based self-lubricating composite material provided by this invention possesses excellent mechanical properties, corrosion resistance, and self-lubricating properties. In corrosive environments, the wear rate is reduced by an order of magnitude compared to aluminum bronze, the coefficient of friction is reduced by 50%, and the strength is increased by 100%. The composite material prepared by the sintering method of this invention can be processed into moving components of various shapes, thus serving as a raw material for the manufacture of moving or transmission parts such as bushings, joint bearings, and bushings for various equipment in marine environments.

[0028] 5. This invention, through special material composition design and network structure control, and by selecting the particle size of each component, controlling the ball milling process and spark plasma sintering, obtains a self-lubricating composite material with a network structure. This overcomes the shortcomings of traditional materials where mechanical properties, corrosion resistance, and wear resistance and self-lubricating properties cannot be simultaneously achieved. The prepared composite material has excellent comprehensive properties of corrosion resistance, high strength, and self-lubrication. Attached Figure Description

[0029] Figure 1The scanning electron microscope photo of the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material for spark plasma sintering.

[0030] Figure 2 The contrastive graph of the friction coefficient curves of the aluminum bronze (QAl10-3-1.5) and the composite material in simulated seawater.

[0031] Figure 3 The contrastive graph of the wear rates of the aluminum bronze (QAl10-3-1.5) and the composite material after the friction test in simulated seawater.

[0032] Figure 4 The friction coefficient curve graph of the nickel-based corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material.

[0033] Figure 5 The compressive strength curve graph of the nickel-based corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material. DETAILED DESCRIPTION

[0034] In the specific implementation process, the present application provides a corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material, which is composed of a metal matrix phase of 65-80% (preferably 70-80%) by weight, a metal reinforcing phase of 10-22% (preferably 15-20%) by weight, a metal self-lubricating phase of 5-10% by weight, and a ceramic self-lubricating phase of 3-8% by weight. The metal matrix phase is nickel, cobalt or nickel-chromium and cobalt-chromium alloy. The metal reinforcing phase is molybdenum, tungsten, tantalum, niobium or a combination of two or more thereof. The self-lubricating phase is silver, tungsten disulfide and molybdenum disulfide. The composite powder is sintered by vacuum spark plasma to obtain the metal-based self-lubricating composite material.

[0035] The following examples are further detailed descriptions of the present application, and it should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application.

[0036] Example 1:

[0037] The nickel-chromium (NiCr20) is used as the metal matrix phase (average particle size 50 μm), the molybdenum is used as the metal reinforcing phase (average particle size 10 μm), and the silver (average particle size 1 μm) and the tungsten disulfide (average particle size 1 μm) are used as the self-lubricating phase to prepare the metal-based self-lubricating composite material, and the specific preparation parameters are as follows:

[0038] (1) Powder mixing: the original powder of the composite material is mixed by a planetary ball mill at a speed of 320 revolutions per minute for 10 hours according to the following ingredient ratio: nickel-chromium (NiCr20) 75 wt%, molybdenum 15 wt%, silver 6%, and tungsten disulfide 4 wt% to obtain the composite powder.

[0039] (2) Spark plasma sintering: the mixed composite powder is put into a graphite mold, compacted, and sintered by spark plasma sintering in vacuum:

[0040] Vacuum: 1 x 10 -3 atm;

[0041] Sintering temperature: 1050°C;

[0042] Heating rate: 60°C / min;

[0043] Sintering pressure: 20 MPa.

[0044] Soaking time: 15 min, and natural cooling after soaking.

[0045] As shown in Figure 1 , the density of the sintered composite material is 99.1%, and it can be seen from the microstructure scanning electron microscope photos that the composite material has a network microstructure, and the components are dispersedly distributed, and no macroscopic or even micron-level defects are found in the scanning electron microscope field of view. The metal reinforcing phase has been solid-solved into the metal matrix, and the metal and the ceramic self-lubricating phase are well combined with the metal matrix.

[0046] Comparative Example 1

[0047] The difference from Example 1 is that the sintering method of the composite material is ordinary vacuum hot-pressing sintering.

[0048] Vacuum: 1 x 10 -3 atm;

[0049] Sintering temperature: 1050°C;

[0050] Heating rate: 60°C / min;

[0051] Sintering pressure: 20 MPa.

[0052] Soaking time: 120 min, and natural cooling after soaking.

[0053] The density of the sintered composite material is 96.1%, which is lower than that of the spark plasma sintered material. The composite material is still a network microstructure in general, and the components are dispersedly distributed. However, a large number of sintering pores and insufficient sintering areas are found in the scanning electron microscope field of view.

[0054] Example 2

[0055] The difference from Example 1 is that nickel is used as the metal matrix phase (average particle size 50 μm), tungsten is used as the metal reinforcing phase (average particle size 10 μm), silver (average particle size 1 μm) and tungsten disulfide (average particle size 1 μm) are used as the self-lubricating phase, and a metal-based self-lubricating composite material is prepared.

[0056] The original composite powder is mixed by ball milling according to the following component ratio: nickel 70wt%, tungsten 17wt%, silver 8wt%, and tungsten disulfide 5wt%. After vacuum discharge plasma sintering, the density of the composite material is 99.2%.

[0057] After 100h salt spray corrosion, the corrosion weight loss of the comparative test sample aluminum bronze (QAl10-3-1.5) reaches 0.091g / (m 2 .h), and the corrosion resistance level is 5, i.e. strong corrosion resistance. The corrosion weight loss of the sintered corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material is only 0.004g / (m 2 .h), and the corrosion rate is reduced by one order of magnitude compared with the aluminum bronze, and the corrosion resistance level is 2, i.e. very strong corrosion resistance.

[0058] Example 3

[0059] Different from Example 1, the metal-based self-lubricating composite material is prepared by taking nickel as the metal matrix phase (average particle size 40μm), molybdenum as the metal reinforcing phase (average particle size 5μm), silver (average particle size 1μm) and tungsten disulfide (average particle size 1μm) as the self-lubricating phase.

[0060] The original composite powder is mixed by ball milling according to the following component ratio: nickel 68wt%, molybdenum 20wt%, silver 8wt%, and tungsten disulfide 4wt%. After vacuum discharge plasma sintering, the density of the composite material is 99.4%.

[0061] After 30min simulated seawater immersion corrosion, the corrosion behaviors of the comparative test sample aluminum bronze (QAl10-3-1.5) and the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material are found. The aluminum bronze material undergoes selective local corrosion, and the corrosion result is the electrochemical dissolution of the aluminum-rich phase. For the composite material, uniform corrosion occurs, and the corrosion degree is very light, and there is no obvious corrosion product on the surface.

[0062] As shown in Figure 2 , the friction coefficient curve comparison of the aluminum bronze and the composite material in seawater shows that the friction coefficient of the aluminum bronze material in seawater is 0.51, and the friction coefficient of the composite material is only 0.21. As shown in Figure 3 , the wear amount comparison of the two materials in seawater friction test shows that the wear amount of the aluminum bronze after friction in seawater is 12.5×10 - 5 mm 3 / (N.m), and the wear amount of the composite material under the same conditions is only 2.1×10 -5 mm 3The wear amount of the composite material is only 1 / 6 of that of the aluminum bronze, and the composite material exhibits excellent corrosion resistance and self-lubricating comprehensive performance compared with the aluminum bronze material.

[0063] Example 4

[0064] Different from Example 1, cobalt-chromium (CoCr20) is used as the metal matrix phase (average particle size 50 μm), niobium is used as the metal reinforcing phase (average particle size 10 μm), and silver (average particle size 1 μm), tungsten disulfide (average particle size 1 μm) and molybdenum disulfide (average particle size 1 μm) are used as the self-lubricating phase to prepare the metal-based self-lubricating composite material.

[0065] The original composite powder is proportioned according to the following components: cobalt-chromium 65 wt%, niobium 20 wt%, silver 10 wt%, tungsten disulfide 3 wt%, and molybdenum disulfide 2 wt%.

[0066] The ball-mixed composite powder is subjected to the vacuum discharge plasma sintering process as follows:

[0067] Vacuum degree: 1×10 -3 atm;

[0068] Sintering temperature: 1000℃;

[0069] Heating rate: 60℃ / min, natural cooling after 15 min of heat preservation at the final sintering temperature;

[0070] Sintering pressure: 30 MPa.

[0071] After 100 h of salt spray corrosion, the corrosion weight loss of the composite material is 0.003 g / (m 2 .h), and the corrosion resistance level is level 2, i.e., the corrosion resistance is very strong.

[0072] The composite material has a density of 98.5%, a compressive strength of 1480 MPa, a compression deformation rate of 25.5%, and a friction coefficient of 0.25.

[0073] Example 5

[0074] Different from Example 1, nickel-chromium (NiCr20) is used as the metal matrix phase (average particle size 50 μm), tantalum and molybdenum are used as the metal reinforcing phase (average particle size 10 μm), and silver (average particle size 1 μm), tungsten disulfide (average particle size 1 μm) and molybdenum disulfide (average particle size 1 μm) are used as the self-lubricating phase to prepare the metal-based self-lubricating composite material.

[0075] The original composite powder is proportioned according to the following components: nickel-chromium 68 wt%, tantalum 12 wt%, molybdenum 5 wt%, silver 8 wt%, tungsten disulfide 5 wt%, and molybdenum disulfide 2 wt%.

[0076] The process of vacuum discharge plasma sintering for ball-milled composite powders is as follows:

[0077] Vacuum degree: 1×10 -3 atm;

[0078] Sintering temperature: 1050℃;

[0079] Heating rate: 60℃ / min, hold at the final sintering temperature for 15 minutes and then cool naturally;

[0080] Sintering pressure: 15MPa.

[0081] After 500 hours of salt spray corrosion, no obvious corrosion marks were observed on the surface of the composite material, and the corrosion weight loss was 0.003 g / (m³). 2 .h), the corrosion resistance level is 2, which means it has very strong corrosion resistance.

[0082] The composite material has a density of 99.3%, a compressive strength of 1460 MPa, a compression deformation rate of 28.0%, and a friction coefficient of 0.22.

[0083] Example 6

[0084] The difference from Example 1 is that a metal-based self-lubricating composite material was prepared using nickel-chromium (NiCr20) as the metal matrix phase (average particle size 50 μm), tungsten and niobium as the metal reinforcing phases (average particle size 10 μm), and silver (average particle size 1 μm) and tungsten disulfide (average particle size 1 μm) as the self-lubricating phases.

[0085] The original powder of the composite material was mixed with the following components in the following proportions: 72 wt% nickel-chromium, 9 wt% tungsten, 6 wt% niobium, 7 wt% silver, and 6 wt% tungsten disulfide. The resulting composite powder was ball-milled and then sintered by vacuum discharge plasma to obtain a composite material with a density of 99.6%.

[0086] like Figure 4 As shown in the curve of the friction coefficient of the composite material, it can be seen that within the test time range (60 min), the friction coefficient of the composite material is low and relatively stable, maintaining at around 0.21.

[0087] like Figure 5 As shown in the figure, the compressive strength test curve of the composite material shows that the compressive strength of the self-lubricating composite material reaches 1510 MPa and the compression rate is about 25.1%, exhibiting good strength and toughness.

[0088] Comparative Example 2

[0089] The difference between the example 1 is that the composition of the metal-based self-lubricating composite material is: nickel-chromium 80wt%, molybdenum 5wt%, silver 10wt%, tungsten disulfide 5wt%, that is, the content of the metal reinforcing phase in the original component of the composite material is too low. The compressive strength of the composite material after sintering is only 1120MPa, which is significantly lower than the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material in examples 5, 6 and 7.

[0090] After the friction test of the composite material, the friction coefficient is 0.27, and slight adhesive wear occurs; the wear rate is 7.1x10 -5 mm 3 The friction coefficient is high, and the wear rate is significantly higher than the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material in examples 5, 6 and 7.

[0091] Example 7

[0092] The difference between the example 1 is that the composition of the metal-based self-lubricating composite material is: nickel-chromium 80wt%, molybdenum 5wt%, silver 10wt%, tungsten disulfide 5wt%, that is, the content of the metal reinforcing phase in the original component of the composite material is too low. The compressive strength of the composite material after sintering is only 1120MPa, which is significantly lower than the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material in examples 5, 6 and 7.

[0093] The original powder of the composite material is mixed according to the following composition: nickel 60wt%, cobalt 10wt%, molybdenum 17wt%, silver 6wt%, tungsten disulfide 5wt%, and molybdenum disulfide 2wt%. After vacuum discharge plasma sintering of the ball-mixed composite powder, the density of the composite material is 99.0%.

[0094] The self-lubricating phase in the composite material after sintering reacts with the nickel matrix, and the silver particles are nanometerized. After the friction test of the composite material, the friction coefficient is 0.23.

[0095] Example 8

[0096] The difference between the example 1 is that the composition of the metal-based self-lubricating composite material is: nickel-chromium 80wt%, molybdenum 5wt%, silver 10wt%, tungsten disulfide 5wt%, that is, the content of the metal reinforcing phase in the original component of the composite material is too low. The compressive strength of the composite material after sintering is only 1120MPa, which is significantly lower than the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite material in examples 5, 6 and 7.

[0097] The original powder of the composite material is mixed according to the following composition: nickel 60wt%, cobalt 10wt%, molybdenum 17wt%, silver 6wt%, tungsten disulfide 5wt%, and molybdenum disulfide 2wt%. After vacuum discharge plasma sintering of the ball-mixed composite powder, the density of the composite material is 99.0%.

[0098] The friction coefficient of the composite material after sintering is 0.25, the surface of the grinding trace is smooth after the friction test, no obvious furrow and sticking wear appears, and the self-lubricating phase is uniformly distributed on the surface of the grinding trace.

[0099] Comparative example 3

[0100] Different from example 1, the composition of the corrosion-resistant self-lubricating composite material is: cobalt 65wt%, tantalum 10wt%, silver 10wt% and tungsten disulfide 15wt% (excessive). The friction coefficient of the composite material after sintering is 0.24, the wear rate is 10.9*10 -5 mm 3 / (N.m), and obvious furrow appears on the surface; the compressive strength is 870MPa, and the compressive deformation rate is 9.5%. Obviously, the wear rate of the composite material is excessive, and the mechanical properties are obviously lower than those of the corrosion-resistant high-strength and high-toughness metal-based self-lubricating composite materials in examples 5, 6 and 7.

[0101] The implementation results show that, by means of special material composition and network structure design, the interface reaction between the self-lubricating phase and the metal matrix phase is regulated in the present application, the interface chemical combination or metallurgical combination is formed, and the solid solution of the metal reinforcing phase is promoted, so that the advantages of high strength and high toughness of the metal matrix phase and the advantages of friction reduction and wear resistance of the self-lubricating phase are fully exerted, and the prepared composite material has excellent corrosion resistance, high strength, high toughness and self-lubricating comprehensive performance.

[0102] The above examples are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable the person skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent change or modification made according to the spirit and essence of the present application should be covered in the protection scope of the present application.

Claims

1. A corrosion-resistant, high-strength, and high-toughness metal-based self-lubricating composite material, characterized in that, The composite material has the following composition by weight percentage: Metal matrix phase 65-80%; Metal-reinforced phase 10–22%; 5-10% of the metal self-lubricating phase; The ceramic self-lubricating phase is 3-8%; The metal matrix phase is nickel, cobalt, nickel-chromium alloy, or cobalt-chromium alloy, and the original powder particle size of the metal matrix phase used to prepare the composite material is 30–70 μm; the metal reinforcing phase is any one or a combination of two or more of molybdenum, tungsten, tantalum, and niobium, and the original powder particle size of the metal reinforcing phase used to prepare the composite material is ≤20 μm; the metal self-lubricating phase is silver or copper-silver alloy, and the ceramic self-lubricating phase is tungsten disulfide and molybdenum disulfide, and the weight percentage of molybdenum disulfide in the composite material is ≤2%; the original powder of the metal self-lubricating phase and the ceramic self-lubricating phase used to prepare the composite material is submicron in size, and the powder particle size is ≤2 μm; The composite material has a network-like microstructure with no surface defects. The metal self-lubricating phase and the ceramic self-lubricating phase are dispersed in the metal matrix phase and are chemically bonded to the matrix interface. The metal reinforcing phase is partially or completely dissolved in the metal matrix phase. The composite material exhibits the following properties in seawater or after salt spray corrosion: density ≥98.0%, corrosion resistance level better than 2, neutral salt spray corrosion life ≥500h, compressive strength ≥1200MPa, and compression deformation rate ≥25%.

2. A method for preparing the corrosion-resistant, high-strength, and high-toughness metal-based self-lubricating composite material according to claim 1, characterized in that, The method includes the following steps: (1) Powder mixing: The metal matrix phase powder, metal reinforcement phase powder, metal self-lubricating phase powder and ceramic self-lubricating phase powder are mixed by planetary ball milling according to the composition ratio of the composite material. The speed is 280-320 rpm and the ball milling time is 10-15 hours to obtain a uniformly mixed composite powder. (2) Vacuum discharge plasma sintering: The composite powder obtained in step (1) is sintered by vacuum discharge plasma to obtain a metal-based self-lubricating composite material.

3. The method for preparing the corrosion-resistant, high-strength, and high-toughness metal-based self-lubricating composite material according to claim 2, characterized in that, The process parameters for vacuum discharge plasma sintering are as follows: Vacuum degree < 1×10 -2 atm; Sintering temperature: 1000~1100℃; Heating rate: 50~100℃ / min; Sintering pressure: 20-30 MPa; Keep warm for 10-20 minutes, then allow to cool naturally.

4. The application of the corrosion-resistant, high-strength, and high-toughness metal-based self-lubricating composite material according to claim 1, characterized in that, This composite material is used in the preparation of bushings, spherical bearings or shaft components for marine oilfield extraction, offshore power, ships and aircraft equipment, and is suitable for cold shrinkage and press-fit assembly of bushings.

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