A lead-free bismuth-copper alloy material, its preparation method and application

Abstract

The present invention discloses a lead-free bismuth copper alloy material, a preparation method thereof and an application thereof. The preparation raw materials include commercially available copper rice and additives; the additives include metal additives and metal nitride additives; the metal additives include tin ingots, bismuth ingots and aluminum ingots; the metal nitride additives include magnesium nitride, chromium nitride and aluminum nitride; by weight, for every 100 parts of the copper rice, 1-5 parts of the tin ingot, 1-5 parts of the bismuth ingot and 1-5 parts of the aluminum ingot are used; by weight, for every 100 parts of the copper rice, 0.1-1 part of the magnesium nitride, 0.1-1 part of the chromium nitride and 0.1-1 part of the aluminum nitride are used; the copper alloy material in this application has better wear resistance, corrosion resistance and cutting effect.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloys, and particularly to a lead-free bismuth copper alloy material. Background Art

[0002] Due to the characteristics of solid lead such as low melting point, anti-seizure property, soft and easy to deform, excellent boundary lubrication property, good affinity with oil, embeddability and good running-in property, it has been widely used as a soft phase or soft matrix in self-lubricating sliding bearing parts for a long time. For example, lead-containing Babbitt alloys, copper-lead alloys, aluminum-lead alloys, etc. are widely used as typical sliding bearing materials.

[0003] Moreover, lead is insoluble in copper and has a very small solid solubility in copper alloys. It forms an easy-melting eutectic structure with copper. In the solid state, lead is distributed in the form of a single substance in copper and can be distributed in the grains and grain boundaries. When the lead-containing copper alloy undergoes phase transformation and recrystallization, the lead at the grain boundaries can transfer into the grains. Lead has no significant effect on the electrical and thermal conductivity of copper alloys, but can improve their cutting performance. The lead particles are also solid phases, which are exactly what is desired for bearing materials. Therefore, lead-containing copper and copper alloys are valuable easy-cutting materials and bearing materials. Lead-containing copper alloys are extremely widely used. The finer and more uniformly distributed the lead particles are, the better the performance. Lead-containing copper and copper alloys can be used in the as-cast state or can be processed by pressure.

[0004] However, since lead is a toxic element, long-term contact with lead-containing substances will cause harm to human health. The lead that enters the human body is very difficult to excrete. The half-life of lead in human blood is up to one month, and the lead in human bones can even last for 20 - 30 years. After lead enters the human body, it can damage the hematopoietic function of the bone marrow, destroy the nervous system, and interfere with normal metabolism. Due to the toxicity of lead, with the enhancement of human environmental protection and health awareness, the use of lead has been strictly restricted. Lead-free involves many fields, such as the lead-free of solders, the lead-free of piezoelectric ceramics, the lead-free of electronic and electrical equipment, and the lead-free of bearing materials, etc. In recent years, the lead-free work in China has also been increasingly valued, and the relevant research work has been continuously deepened. However, compared with advanced foreign countries, there is still a certain gap in the research on the lead-free of bearing materials in China.

[0005] Therefore, in order to improve the comprehensive performance of the bismuth copper alloy material in the lead-free situation, so that it has more excellent wear resistance, corrosion resistance and cutting effect, the present application provides a solution. Summary of the Invention

[0006] The object of the present invention is to design a lead-free bismuth copper alloy material so that the copper alloy material has more excellent wear resistance, corrosion resistance and cutting effect in the lead-free situation.

[0007] In a first aspect, a lead-free bismuth copper alloy material designed by the present invention has raw materials for preparation including commercially available copper rice and additives; the additives include metal additives and metal nitride additives; the metal additives include tin ingots, bismuth ingots and aluminum ingots; the metal nitride additives include magnesium nitride, chromium nitride and aluminum nitride; by weight, for every 100 parts of the copper rice, 1-5 parts of the tin ingots, 1-5 parts of the bismuth ingots and 1-5 parts of the aluminum ingots are combined; by weight, for every 100 parts of the copper rice, 0.1-1 part of the magnesium nitride, 0.1-1 part of the chromium nitride and 0.1-1 part of the aluminum nitride are combined; the lead-free wear-resistant bismuth copper alloy material is obtained through secondary modification; the metal additives are added during the first modification process; the metal nitride additives are added during the second modification process; the mass of the metal additives is 2-10 times greater than the mass of the metal nitride additives.

[0008] By adopting the above technical solution, in the first modification, the tin in the tin ingot will be dispersed and dissolved in the copper alloy matrix, which can strengthen the grain boundaries of the copper alloy, greatly reduce the corrosion sensitivity of the grain boundaries, and improve the corrosion resistance; and improve the casting performance, reducing defects such as pores and porosity in subsequent castings. However, when the tin content increases, it will lead to an increase in the alloy cost, and in the present invention, the tin content is reduced as much as possible under the condition of meeting the use performance of tin. The bismuth in the bismuth ingot has a similar action characteristic to lead in the copper alloy matrix and is beneficial to improving the cutting performance of the copper alloy. However, if the bismuth content in the copper alloy matrix is excessive, it is easy to cause agglomeration at the phase boundary of the copper alloy matrix, resulting in hot cracking of the copper alloy casting. In the present invention, the bismuth content is reduced as much as possible under the condition of meeting the use performance. The aluminum in the aluminum ingot can not only improve the melt fluidity, but also is beneficial to generating a dense Al 2 O 3 oxide film on the surface of the alloy to play a passivation and corrosion prevention role; however, when the aluminum content is on the high side, it is easy to cause relatively serious solid solution strengthening, making the alloy hardness on the high side and being not conducive to cutting processing.

[0009] In the secondary modification, metal nitrides are beneficial to filling the pores and defects on the copper alloy matrix, thereby enhancing the surface density and continuity of the copper alloy, and also improving the corrosion resistance of the copper alloy material. Generally, the floating bearings of turbochargers in motors are low-speed and heavy-load bearings, and the copper alloy materials used in them have high hardness and strong bonding ability. Therefore, by adding magnesium nitride, a regular structure is formed on the crystal plane of the copper alloy, thereby reducing the anti-adhesion ability. However, if too much magnesium nitride is added to the surface of the copper alloy, the anti-adhesion ability will be too low, resulting in an increase in the friction coefficient. Therefore, in the present invention, the content of magnesium nitride is reduced as much as possible under the condition of meeting the use performance. Adding chromium nitride can increase the surface hardness of the copper alloy, but the brittleness of the copper alloy surface will increase. Moreover, due to the very small radius of hydrogen atoms, it is easy to enter the lattice voids of metals and diffuse. After atoms recombine at the material defect positions or react with other substances to form gaseous molecules, the volume expands rapidly, resulting in cracks at that position. By adding aluminum nitride, a hydrogen storage layer is formed on the surface, thereby reducing the probability of hydrogen embrittlement. In addition, a corrosion-resistant protective layer is formed on the surface.

[0010] Preferably, in the metal nitride additive; the magnesium nitride is nano magnesium nitride particles with a particle size of 20-100 nm; the chromium nitride is nano magnesium nitride particles with a particle size of 20-100 nm; the aluminum nitride is nano aluminum nitride particles with a particle size of 20-100 nm.

[0011] By adopting the above technical solution, controlling the particle sizes of the nano magnesium nitride particles, the nano magnesium nitride particles and the nano aluminum nitride particles within a certain range can not only make the distribution of the interphase more uniform, increase the contact area between the main phase grains, and effectively improve the properties of the copper alloy.

[0012] On the other hand, the present invention provides a preparation method of a lead-free bismuth copper alloy material, including the following steps: primary modification: weighing commercially available copper powder and metal additives in set weight portions, melting them together, and performing shaped casting on the molten liquid on a cooling roller to obtain a copper alloy rough product; secondary modification: weighing nano magnesium nitride, nano chromium nitride and nano aluminum nitride in set weight portions, respectively making slurries and coating them on the surface of the copper alloy rough product; diffusion sintering: sintering the copper alloy rough product coated with the secondary modification additive in a nitrogen atmosphere to obtain a copper alloy material.

[0013] Preferably, in the primary modification step, the tin ingot, the bismuth ingot and the aluminum ingot are all subjected to lead washing treatment.

[0014] By adopting the above technical solution, since lead is a toxic element, long-term contact with lead-containing substances will pose a hazard to human health. Lead-free involves many fields, and in our country, lead-free is an inevitable trend. The present invention aims at reducing the entry of lead into the copper alloy matrix in the form of impurities by lead-washing tin ingots, bismuth ingots and aluminum ingots during the primary modification of copper alloys.

[0015] Preferably, in the secondary modification step, the nano-magnesium nitride is added to the silica dispersion (hydrolyzed silica solution), and ammonia is introduced to increase the pH of the solution to 8.0 - 9.0 to form a gel slurry of nano-magnesium nitride; the nano-chromium nitride is added to the silica dispersion, and ammonia is introduced to increase the pH of the solution to 8.0 - 9.0 to form a gel slurry of nano-chromium nitride; the nano-aluminum nitride is added to the silica dispersion, and ammonia is introduced to increase the pH of the solution to 8.0 - 9.0 to form a gel slurry of nano-aluminum nitride.

[0016] During the secondary modification process, the surface of the copper alloy rough product is modified by uniformly dispersing nano-magnesium nitride particles, nano-magnesium nitride particles and nano-aluminum nitride particles on the surface of the copper alloy rough product, which is beneficial to the modification of the copper alloy. At the same time, in the subsequent sintering process of the dispersion formed by silica, the silicon therein has a solid solution strengthening and deoxidation effect, forming a micro-ceramic coating and forming a eutectic with the matrix phase.

[0017] Preferably, in the secondary modification step, the preparation of the silica dispersion: tetraethyl orthosilicate is hydrolyzed in a hydrochloric acid solution with a pH of 3 - 4 for 20 - 60 minutes, and polyacrylamide is added while stirring during the hydrolysis process to obtain a hydrolyzed silica solution; by weight, every 100 parts by weight of tetraethyl orthosilicate requires 50 - 100 parts by weight of hydrochloric acid solution with a pH of 3 - 4 for hydrolysis, and 10 - 20 parts by weight of polyacrylamide is added during the hydrolysis process.

[0018] By adopting the above technical solution, since the particles of nano-silica are extremely fine, the surface atom ratio is high, the specific surface area is large, and the particles are extremely easy to attract each other through the action of van der Waals force, hydrogen bond and covalent bond to form agglomerates such as secondary particle size and tertiary particle size; according to the characteristics of nano-silica being easy to agglomerate and difficult to disperse. The hydrolysis of tetraethyl orthosilicate is carried out to improve the uniformity of the silica dispersion. And it is found that when adding polyacrylamide as a chelate of metal ions, polyacrylamide can play a promoting role in the hydrolysis of tetraethyl orthosilicate, which is beneficial to improving the characteristics of the copper alloy matrix during the sintering process.

[0019] Preferably, the magnesium nitride nanogel slurry, the chromium nitride nanogel slurry, and the aluminum nitride nanogel slurry are mixed according to a ratio of 5:(1 - 10):(1 - 10) and coated on the surface of the rough copper alloy.

[0020] By adopting the above technical solution, since the silica dispersion obtained by the hydrolysis of tetraethyl orthosilicate has different solubilities for different metal nitrides, and a uniform dispersed solution layer is used for coating, there will be errors in the specific ratio according to the differences in metal nitrides. Therefore, separately preparing the gel slurry of magnesium nitride nanogel, the gel slurry of chromium nitride nanogel, and the gel slurry of aluminum nitride nanogel is beneficial for formulating according to the ratio of nanometer metal nitrides in the gel slurry in the actual environment.

[0021] Preferably, in the step of diffusion sintering, the rough copper alloy coated with the secondary modification additive is placed in a spark plasma sintering furnace for sintering; the sintering temperature of the spark plasma sintering furnace is 700 - 1000 °C, the heating rate is 50 - 70 °C / min, the pressure is 60 - 90 Mpa, and the heat preservation time is 30 - 90 min.

[0022] By adopting the above technical solution, since the additive used in the secondary modification is a metal nitride, a huge amount of energy is required to excite the metal arrangement and improve the densification degree. Through multiple experiments, it is found that in the range of 700 - 1000 °C and 60 - 90 Mpa, there is a sintering area with a relatively high densification degree, the lattice arrangement of the metal is neat, the contact area of the crystal planes is close, and sufficient heat is generated by passing through a large enough current to make the boundary dense.

[0023] Finally, the lead - free wear - resistant bismuth - copper alloy material in the present invention is applied to components such as the floating bearing of the turbocharger in the motor. Detailed implementation mode

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0025] Raw materials

[0026] Copper rice, with a CAS number of 7440 - 50 - 8, and the copper rice of grade YT - C is used in this embodiment;

[0027] Tin ingot, with a CAS number of 7440 - 31 - 5 and a purity of 99.9%, and the mass of each tin ingot is 500 - 1000 g in this embodiment;

[0028] Bismuth ingot, with a CAS number of 7440-69-9 and a purity of 99.9%. In this example, the mass of each bismuth ingot is 500-1000g;

[0029] Aluminum ingot, with a CAS number of 7429-90-5 and a purity of 99.9%. In this example, the mass of each aluminum ingot is 500-1000g;

[0030] Magnesium nitride nanometer, with a CAS number of 12057-71-5 and a purity ≥ 99.9%. In this example, it is illustrated with 100 ± 10nm;

[0031] Chromium nitride nanometer, with a CAS number of 12053-27-9 and a purity ≥ 99.9%. In this example, it is illustrated with 100 ± 10nm;

[0032] Aluminum nitride nanometer, with a CAS number of 24304-00-5 and a purity ≥ 99.9%. In this example, it is illustrated with 100 ± 10nm;

[0033] Tetraethyl orthosilicate, with a CAS number of 78-10-4 and a purity ≥ 99.9%;

[0034] Polyacrylamide, with a CAS number of 9003-05-8 and a purity ≥ 98.0%, anionic PAM, with a molecular weight less than 1 million.

[0035] Preparation example

[0036] Silica dispersion (hydrolyzed silica solution): Add 5 kg of 0.001 mol / L hydrochloric acid solution to 10 kg of tetraethyl orthosilicate for hydrolysis to obtain a colloidal solution with a uniform medium. During the hydrolysis process, stir while adding 1 kg of polyacrylamide, stir for a total of 20 minutes, and complete the feeding within 20 minutes to obtain the hydrolyzed silica solution.

[0037] Example

[0038] Example 1

[0039] A lead-free bismuth copper alloy material, and its preparation method includes the following steps:

[0040] S1 Primary modification: Weigh 100 kg of commercially available copper rice, 1 kg of bismuth ingot (after lead washing treatment), 1 kg of aluminum ingot (after lead washing treatment), and 1 kg of tin ingot (after lead washing treatment), put them into a furnace for co-melting, and slowly cool and cast the molten liquid in a water-cooled roller. The rotation speed of the water-cooled roller is 10 m / s, and the thickness of the cast sheet is 300 μm to obtain a copper alloy crude product;

[0041] S2 Secondary modification: Weigh 10 kg of the hydrolyzed silica solution obtained in the preparation example, add 1 kg of nano magnesium nitride particles thereto, and introduce ammonia during stirring to keep the solution at a pH of 8 to form a nano magnesium nitride gel slurry. Similarly, prepare a nano chromium nitride gel slurry and a nano aluminum nitride gel slurry. Then, mix 0.1 kg of the nano magnesium nitride gel slurry, 0.1 kg of the nano chromium nitride gel slurry, and 0.1 kg of the nano aluminum nitride gel slurry according to a ratio of 1:1:1 and coat the surface of the rough copper alloy product.

[0042] S3 Diffusion sintering: Place the rough copper alloy product coated with the secondary modification additive in a spark plasma sintering furnace for sintering; the sintering temperature of the spark plasma sintering furnace is 700 °C, the heating rate is 50 °C / min, the pressure is 60 Mpa, and the heat preservation time is 30 min, thereby obtaining the copper alloy material.

[0043] Example 2 - 15

[0044] In Example 2 - 15, based on the preparation method of Example 1, the component contents between the metal additive and the metal nitride additive and the copper powder were adjusted.

[0045] The specific component adjustment situations of the above Examples 1 - 15 are shown in Table 1 below, with the unit being kg.

[0046] Table 1. Component Table of Preparation Raw Materials for Copper Alloy Modification

[0047] Copper rice Tin ingot Bismuth ingot Aluminum ingot Nano magnesium nitride Nano chromium nitride Nano aluminum nitride Example 1 100 1 1 1 0.1 0.1 0.1 Example 2 100 1 3 2 0.1 0.3 0.2 Example 3 100 1 5 4 0.2 0.5 0.3 Example 4 100 2 2 1 0.2 0.2 0.4 Example 5 100 2 3 3 0.3 0.4 0.5 Example 6 100 2 5 4 0.3 0.1 0.1 Example 7 100 3 1 1 0.4 0.3 0.2 Example 8 100 3 3 2 0.4 0.5 0.3 Example 9 100 3 5 4 0.5 0.4 0.4 Example 10 100 4 2 1 0.5 0.3 0.5 Example 11 100 4 3 3 0.1 0.1 0.1 Example 12 100 4 5 4 0.2 0.3 0.2 Example 13 100 5 2 2 0.3 0.2 0.3 Example 14 100 5 3 4 0.4 0.4 0.4 Example 15 100 5 5 5 0.5 0.5 0.5

[0048] Comparative Example

[0049] Comparative Example 1

[0050] The difference between Comparative Example 1 and Example 1 is that the surface of the copper powder was treated by secondary modification, and primary modification was not used for the modification treatment of the copper powder.

[0051] Comparative Example 2

[0052] The difference between Comparative Example 1 and Example 1 is that the copper powder was improved by primary modification, and secondary modification was not used for the surface treatment of the copper powder.

[0053] Performance Detection Test

[0054] For the copper - titanium alloys provided in Examples 1 - 15 and Comparative Examples 1 - 2 of this application, performance detection tests were carried out, and the specific performance values are referred to Table 2.

[0055] 1. Tensile Measurement of Metal Materials

[0056] According to the latest national standard GB / T 228.1-2021, for "Metallic materials - Tensile testing - Part 1: Method of test at room temperature", the copper alloy in the examples is analyzed and determined from the perspectives of tensile strength and elongation rate.

[0057] 2. Determination of corrosion resistance

[0058] Place the copper alloy material in a sealed box with a constant temperature set at 90°C, and the oxygen concentration in the sealed box is set at 50%, and test the time when rust spots first appear on the surface of the copper alloy material; according to the national standard GB / T10125-1997, conduct a neutral salt spray test (NSS test) on the metal coating of the copper alloy material, and test the time when rust spots first appear on the surface of the copper alloy material.

[0059] 3. Determination of cutting index

[0060] Evaluate according to the cutting performance detection method in Appendix B of YS-T 647-2007 "Copper-zinc-bismuth-tellurium alloy rods", and set the cutting index of HPb63-3 lead brass as 100% as the index reference control.

[0061] 4. Determination of lead content in the alloy

[0062] According to GB / T 5121.3-2008, for "Methods for chemical analysis of copper and copper alloys - Part 3: Determination of lead content", the lead content in the copper alloy material in the examples is determined.

[0063] Table 2. Performance test data table

[0064]

[0065]

[0066] The following combines the test data provided in Table 2 to elaborate on this application in detail.

[0067] In Examples 1-15, the component contents between the metal additives and the metal nitride additives and the copper powder are changed to improve the modification effect of the copper alloy material. Among them, in combination with Comparative Examples 1 and 2, the primary modification improves the tensile strength and elongation rate of the copper alloy by changing the metal ratio in the alloy, and can also greatly improve in terms of cutting; at the same time, the secondary modification improves the corrosion resistance of the copper alloy material by modifying the surface of the copper alloy material. The copper alloy material obtained in Example 1 is subjected to hardness test and bonding ability test for actual application, and compared with the hardness test and bonding ability test in Comparative Example 2, it is obtained that under the condition of secondary modification, it is more beneficial to be applied on low-speed heavy-duty bearings. According to Table 2, the optimal example is 8.

[0068] Example

[0069] Examples 16 - 20

[0070] Based on the preparation method of Example 8, Examples 16 - 20 changed the parameters for preparing the hydrolyzed silica solution.

[0071] Table 3. Component Table of Raw Materials for Surface Modification of Copper Alloy Materials

[0072]

[0073]

[0074] The copper alloy materials prepared in Examples 16 - 20 above were tested according to the above performance detection tests, and the test results were combined with those of Example 9. See Table 4 below.

[0075] Table 4. Performance Detection Data Table

[0076]

[0077] The present application will be described in detail below in combination with the detection data provided in Table 4. Among Examples 16 - 20, the parameters for preparing the hydrolyzed silica solution were changed, and it was found that while changing the parameters, Example 18 was the optimal example. The parameters for preparing the hydrolyzed silica solution used therein could make the surface modification of the copper alloy material more perfect. In addition, it could make nano - magnesium nitride, nano - chromium nitride, and nano - aluminum nitride disperse more evenly in the gel slurry, and could increase the performance of the copper alloy material after being coated on the surface of the copper alloy material.

[0078] Examples 21 - 23

[0079] Based on the preparation method of Example 18, Examples 21 - 23 adjusted the process optimization data of the spark plasma sintering furnace.

[0080] The process optimization data of the spark plasma sintering furnace in Examples 21 - 23 above are shown in Table 5 below.

[0081] Table 5. Process Optimization Data Table of Spark Plasma Sintering Furnace

[0082] Sintering temperature (°C) Pressure (Mpa) Heat preservation time (min) Example 18 700 60 30 Example 21 800 70 50 Example 22 900 80 70 Example 23 1000 90 90

[0083] The copper alloy materials prepared in Examples 21 - 23 above were tested according to the above performance detection tests, and the test results were combined with those of Example 18. See Table 6 below.

[0084] Table 6. Performance Detection Data Table

[0085]

[0086] The present application will be described in detail below in conjunction with the detection data provided in Table 6. Among them, in Examples 21-23, the process optimization data of the spark plasma sintering furnace was changed. As a result, at 900 °C and 80 Mpa for 70 minutes of heat preservation, a more densified sintering region appeared on the surface of the copper alloy material. The lattice arrangement of the metal was neat, the contact area of the crystal planes was tight, and it had a better modification effect. Example 22 was the optimal example.

[0087] In all examples of the present application, the lead content of the copper alloy material is lower than the standard for floating bearing applications in GB / T 5121.3-2008, "Methods for Chemical Analysis of Copper and Copper Alloys - Part 3: Determination of Lead Content", and can be applied to production practice. Moreover, the overall performance of the copper alloy material is better than that of copper alloy materials on the market.

[0088] Testing the hardness and bonding ability of the copper alloy material in the optimal Example 22 has better advantages when applied to the floating bearing of the turbocharger in the motor.

[0089] The present invention is not limited to the above best embodiment. Anyone can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as it has the same or similar technical solutions as the present application, it falls within the protection scope of the present invention.

Claims

1. A lead-free bismuth copper alloy material, characterized in that, its preparation raw materials include commercially available copper rice and additives; the additives include metal additives and metal nitride additives; the metal additives include tin ingots, bismuth ingots and aluminum ingots; the metal nitride additives include magnesium nitride, chromium nitride and aluminum nitride; by weight, for every 100 parts of the copper rice, 1-5 parts of the tin ingot, 1-5 parts of the bismuth ingot and 1-5 parts of the aluminum ingot are combined; by weight, for every 100 parts of the copper rice, 0.1-1 part of the magnesium nitride, 0.1-1 part of the chromium nitride and 0.1-1 part of the aluminum nitride are combined; The preparation of the lead-free wear-resistant bismuth copper alloy material includes the following steps: primary modification: weighing commercially available copper rice and metal additives in set weight parts and melting them together, and subjecting the molten liquid to shaped casting on a cooling roller to obtain a copper alloy rough product; secondary modification: weighing set weight parts of nano magnesium nitride, nano chromium nitride and nano aluminum nitride, respectively making slurries and coating them on the surface of the copper alloy rough product; diffusion sintering: sintering the copper alloy rough product coated with the secondary modification additives in a nitrogen atmosphere to obtain a copper alloy material; wherein in the secondary modification process: the nano magnesium nitride is added to a silica dispersion liquid, and ammonia is introduced to increase the pH of the solution to 8.0-9.0 to form a nano magnesium nitride gel slurry; the nano chromium nitride is added to a silica dispersion liquid, and ammonia is introduced to increase the pH of the solution to 8.0-9.0 to form a nano chromium nitride gel slurry; the nano aluminum nitride is added to a silica dispersion liquid, and ammonia is introduced to increase the pH of the solution to 8.0-9.0 to form a nano aluminum nitride gel slurry; the nano magnesium nitride gel slurry, the nano chromium nitride gel slurry and the nano aluminum nitride gel slurry are mixed and coated on the surface of the copper alloy rough product according to a ratio of 5:1-10:1-10; The preparation of the silica dispersion liquid: tetraethyl orthosilicate is hydrolyzed in a hydrochloric acid solution with a pH of 3-4 for 20-60 min, and polyacrylamide is added while stirring during the hydrolysis process to obtain a hydrolyzed silica solution; by weight, for every 100 parts by weight of the tetraethyl orthosilicate, 50-100 parts by weight of the hydrochloric acid solution with a pH of 3-4 is required for hydrolysis, and 10-20 parts by weight of polyacrylamide is added during the hydrolysis process; in the step of the diffusion sintering, the copper alloy rough product coated with the secondary modification additives is placed in a spark plasma sintering furnace for sintering; the sintering temperature of the spark plasma sintering furnace is 700-1000 °C, the heating rate is 50-70 °C / min, the pressure is 60-90 MPa, and the holding time is 30-90 min; the mass of the metal additives is 2-10 times greater than the mass of the metal nitride additives.

2. The lead-free wear-resistant bismuth copper alloy material according to claim 1, characterized in that, among the metal nitride additives; the magnesium nitride is nano magnesium nitride particles with a particle size of 20-100 nm; the chromium nitride is nano magnesium nitride particles with a particle size of 20-100 nm; The aluminum nitride is nano-aluminum nitride particles with a particle size of 20-100 nm.

3. The lead-free wear-resistant bismuth-copper alloy material according to claim 1, characterized in that in the primary modification step, the tin ingot, the bismuth ingot and the aluminum ingot are all subjected to lead washing treatment.

4. Application of the lead-free wear-resistant bismuth-copper alloy material according to any one of claims 1-2 in the floating bearing parts of a turbocharger in an electric motor.

Images