A Ti-Al-C based conductive wear-resistant composite coating on copper alloy surface and preparation method thereof

Abstract

The present invention relates to the technical field of copper alloy surface wear protection, and in particular to a copper alloy surface Ti-Al-C based conductive wear-resistant composite coating and a preparation method thereof. First, raw materials Ti powder, Al powder and graphite powder are selected, Ti-Al-C powder is prepared by spray granulation, powder bonding strength is improved by vacuum sintering, and the polyvinyl alcohol binder used during granulation is removed, the sintered Ti-Al-C powder and Cu powder are mixed by an automatic mixer to prepare composite coating powder, atmospheric plasma spraying equipment is used for coating preparation, Ti-Al-C / Cu composite coating with a thickness of 200 to 300 μm is prepared on the surface of a Cu substrate, and the Cu substrate is subjected to surface sandblasting and alcohol ultrasonic cleaning before spraying. The coating phases prepared under such conditions include a reinforcing phase TiC phase and a TiAl phase formed by reaction, a lubricating conductive phase Ti2AlC phase formed by reaction, and unreacted conductive Ti, Cu and other phases, thereby achieving low-cost preparation of the conductive wear-resistant composite coating.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloy surface wear protection, and in particular to a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface and a preparation method thereof. Background Art

[0002] Copper alloys are widely used in brushes, pantograph slides, integrated circuit lead frames, and electromagnetic gun rails due to their excellent electrical conductivity, ductility, and machinability. However, their lack of strength, hardness, and wear resistance limits their widespread application. Surface coating technology is often used to overcome the problems of insufficient hardness and poor wear resistance of copper alloys. Ti2AlC, a typical representative of MAX phases, possesses the high hardness, high wear resistance, and good oxidation resistance of ceramics, as well as the excellent thermal and electrical conductivity and good plasticity of metals, and is considered to be an ideal conductive and wear-resistant coating material. Ti2AlC powder is expensive, and direct spraying is prone to high-temperature decomposition of the Ti2AlC phase material, resulting in deterioration of the performance of the Ti2AlC phase coating material. Therefore, direct spraying to prepare Ti2AlC phase coatings is not economical from an industrial perspective and has limited success.

[0003] In view of the above-mentioned defects, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems that the cost of preparing Ti2AlC powder is high and direct spraying easily causes high-temperature decomposition of Ti2AlC phase materials, resulting in performance degradation of Ti2AlC phase coating materials. A Ti-Al-C based conductive wear-resistant composite coating on the surface of a copper alloy and a preparation method thereof are provided.

[0005] In order to achieve the above object, the present invention discloses a method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface, comprising the following steps:

[0006] S1, adding Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose into deionized water and stirring to prepare Ti-Al-C powder granulation slurry;

[0007] S2, preparing Ti-Al-C spherical powder from the Ti-Al-C powder granulation slurry obtained in step S1 by spray granulation, and vacuum sintering the slurry to obtain Ti-Al-C powder;

[0008] S3, mechanically mixing the Ti-Al-C powder obtained in step S2 with Cu powder to obtain a Ti-Al-C / Cu composite powder;

[0009] S4, sandblasting and ultrasonic cleaning of the Cu substrate spray surface;

[0010] S5, performing atmospheric plasma spraying using the Ti-Al-C / Cu composite powder prepared in step S3 to obtain a Ti-Al-C / Cu composite thick coating of 200 to 300 μm.

[0011] In step S1, the molar ratio of Ti powder, Al powder and graphite powder is 2:1:1, the particle size of Ti powder is 5-30 μm, the particle size of Al powder is 3-15 μm, and the particle size of graphite powder is 1-5 μm.

[0012] In step S1, the mass of deionized water is 1.5 times the mass of the powder, the mass of polyvinyl alcohol is 2.5% of the mass of the powder, and the mass of sodium carboxymethyl cellulose is 0.5% of the mass of the powder.

[0013] In step S2, the vacuum degree during sintering is 1×10 -2 Pa, the heating process is as follows: heat from room temperature to 300℃ at 10℃ / min, then heat to 610-650℃ at 5℃ / min, keep warm for 2 hours, and cool with the furnace after the end of the heat preservation.

[0014] In step S3, the Ti-Al-C composite powder accounts for 40-60% of the total molar ratio, and the Cu powder is a spherical powder of 30-60 μm.

[0015] In step S5, the spraying parameters are as follows: current is 450-500 A, power is 30-32 kW, main gas flow rate of argon is 30-45 L / min, linear speed is 450-550 mm / s, and spraying distance is 90-110 mm.

[0016] The invention also discloses a Ti-Al-C based conductive wear-resistant composite coating on the surface of the copper alloy prepared by the preparation method.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention selects low-cost Ti, Al and graphite powder, prepares Ti-Al-C spherical powder by granulation, and adopts atmospheric plasma spraying to prepare Ti-Al-C / Cu composite coating, the preparation method is simple, the preparation cost is low, and through process control, the reinforcing phase TiC phase and TiAl phase, the lubricating conductive phase Ti2AlC phase, and the unreacted conductive Ti, Cu and other phases are obtained, which are well combined with the matrix and have good wear resistance and conductivity, thereby realizing the low-cost preparation of the conductive wear-resistant composite coating, which can be applied as a conductive wear-resistant material on the surface of copper alloy materials to improve the current-carrying wear resistance of the copper alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The powder morphology of the embodiment of the present invention and comparative example 2;

[0019] Figure 2This is a cross-sectional morphology diagram of the coating according to an embodiment of the present invention;

[0020] Figure 3 The hardness test results of the embodiment of the present invention and comparative example 3 are shown;

[0021] Figure 4 The conductivity test results of the embodiment of the present invention and comparative example 4 are shown;

[0022] Figure 5 The porosity test results of the embodiment of the present invention and comparative example 5 are shown;

[0023] Figure 6 The hardness test results of the embodiment of the present invention and comparative example 6 are shown in FIG.

[0024] Figure 7 The wear marks of current-carrying friction and wear of the embodiment of the present invention and comparative example 1 are shown. DETAILED DESCRIPTION

[0025] The above and other technical features and advantages of the present invention are described in more detail below with reference to the accompanying drawings.

[0026] Example 1

[0027] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0028] S2: The Ti-Al-C powder granulation slurry obtained in step S1 is prepared into Ti-Al-C spherical powder by spray granulation, and the powder is vacuum sintered to obtain Ti-Al-C powder. The vacuum degree during sintering is maintained at 1×10 -2 Pa, the heating process is from room temperature to 300℃ at 10℃ / min, then to 630℃ at 5℃ / min, and keep warm for 2 hours. After the end of the heat preservation, the furnace is cooled.

[0029] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 50% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0030] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0031] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 30 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0032] Comparative Example 1

[0033] Untreated copper alloy.

[0034] The wear marks of current-carrying friction and wear of the embodiment and comparative example 1 are as follows Figure 7 As shown, the wear condition of Comparative Example 1 is more serious than that of the embodiment, which indicates that the performance of the embodiment in resisting current-carrying friction and wear is much better than that of the comparative example.

[0035] Comparative Example 2

[0036] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0037] S2: The Ti—Al—C powder granulation slurry obtained in step S1 is prepared into Ti—Al—C spherical powder by spray granulation.

[0038] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 50% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0039] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0040] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 30 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0041] The powder of Comparative Example 2 was not sintered, and its powder morphology was compared with the powder after sintering in Example 2. Figure 1 As shown, the unsintered powder is brittle, resulting in a low proportion of spherical powder and poor fluidity, which leads to low spraying efficiency and poor coating performance.

[0042] Comparative Example 3

[0043] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0044] S2: The Ti-Al-C powder granulation slurry obtained in step S1 is prepared into Ti-Al-C spherical powder by spray granulation, and the powder is vacuum sintered to obtain Ti-Al-C powder. The vacuum degree during sintering is maintained at 1×10 -2 Pa, the heating process is from room temperature to 300℃ at 10℃ / min, then to 630℃ at 5℃ / min, and keep warm for 2 hours. After the end of the heat preservation, the furnace is cooled.

[0045] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 20% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0046] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0047] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 30 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0048] The hardness test results of Example 3 and Comparative Example 3 are as follows Figure 3 As shown in the figure, when the Ti-Al-C powder content is insufficient, the hardness of the coating decreases significantly and the wear resistance of the coating is poor.

[0049] Comparative Example 4

[0050] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0051] S2: The Ti-Al-C powder granulation slurry obtained in step S1 is prepared into Ti-Al-C spherical powder by spray granulation, and the powder is vacuum sintered to obtain Ti-Al-C powder. The vacuum degree during sintering is maintained at 1×10 -2 Pa, the heating process is from room temperature to 300℃ at 10℃ / min, then to 630℃ at 5℃ / min, and keep warm for 2 hours. After the end of the heat preservation, the furnace is cooled.

[0052] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 80% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0053] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0054] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 30 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0055] The conductivity test results of Example 4 and Comparative Example 4 are as follows Figure 4 As shown in the figure, when the Ti-Al-C powder content is too high, the content of ceramic phase by-products is high, which leads to a decrease in the electrical conductivity of the coating, affecting the conductive properties and resistance to current-carrying friction and wear of the coating.

[0056] Comparative Example 5

[0057] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0058] S2: The Ti-Al-C powder granulation slurry obtained in step S1 is prepared into Ti-Al-C spherical powder by spray granulation, and the powder is vacuum sintered to obtain Ti-Al-C powder. The vacuum degree during sintering is maintained at 1×10 -2 Pa, the heating process is from room temperature to 300℃ at 10℃ / min, then to 630℃ at 5℃ / min, and keep warm for 2 hours. After the end of the heat preservation, the furnace is cooled.

[0059] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 50% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0060] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0061] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 25 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0062] The porosity test results of Example 5 and Comparative Example 5 are as follows Figure 5 As shown in the figure, when the spraying power is low, the powder melting is poor and the coating porosity is high, which affects the coating's electrical conductivity and resistance to current-carrying friction and wear.

[0063] Comparative Example 6

[0064] S1: Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose were added to deionized water and stirred to prepare a Ti-Al-C powder granulation slurry. The molar ratio of Ti:Al:C was 2:1:1, and the Ti powder particle size was 5-30 μm, the Al powder particle size ranged from 3-15 μm, and the graphite powder particle size was 1-5 μm.

[0065] S2: The Ti-Al-C powder granulation slurry obtained in step S1 is prepared into Ti-Al-C spherical powder by spray granulation, and the powder is vacuum sintered to obtain Ti-Al-C powder. The vacuum degree during sintering is maintained at 1×10 -2 Pa, the heating process is from room temperature to 300℃ at 10℃ / min, then to 630℃ at 5℃ / min, and keep warm for 2 hours. After the end of the heat preservation, the furnace is cooled.

[0066] S3: Mechanically mix the Ti-Al-C powder obtained in S2 with Cu powder, wherein the Ti-Al-C composite powder accounts for 50% of the total molar ratio and the Cu powder is a 30-60 μm spherical powder, thereby obtaining a Ti-Al-C / Cu composite powder.

[0067] S4: The sprayed surface of the Cu substrate is roughened by sandblasting and cleaned by alcohol ultrasonic cleaning.

[0068] S5: Atmospheric plasma spraying was performed with a current of 460 A, a power of 35 kW, a main gas flow rate of argon gas of 45 L / min, a linear speed of 500 mm / s, and a spraying distance of 100 mm to obtain a Ti-Al-C / Cu composite coating.

[0069] The hardness test results of Example 6 and Comparative Example 6 are as follows Figure 6 As shown in the figure, when the spraying power is high, more oxides are generated in the coating, which affects the hardness of the coating and causes the coating's resistance to current-carrying friction and wear to decrease.

[0070] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative rather than restrictive of the present invention. Those skilled in the art will appreciate that many changes, modifications, and even equivalents may be made to the present invention within the spirit and scope of the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface, characterized in that: The following steps are involved: S1, adding Ti powder, Al powder, graphite powder, polyvinyl alcohol, and sodium carboxymethyl cellulose into deionized water and stirring to prepare Ti-Al-C powder granulation slurry; S2, preparing Ti-Al-C spherical powder from the Ti-Al-C powder granulation slurry obtained in step S1 by spray granulation, and vacuum sintering the slurry to obtain Ti-Al-C powder; S3, mechanically mixing the Ti-Al-C powder obtained in step S2 with Cu powder to obtain a Ti-Al-C / Cu composite powder; S4, sandblasting and ultrasonic cleaning of the Cu substrate spray surface; S5, performing atmospheric plasma spraying using the Ti-Al-C / Cu composite powder prepared in step S3 to obtain a Ti-Al-C / Cu composite thick coating of 200-300 μm; In step S2, the vacuum degree during sintering is 1×10 -2 Pa, the heating process is as follows: heating from room temperature to 300℃ at 10℃ / min, then heating to 610~650℃ at 5℃ / min, keeping warm for 2 hours, and cooling with the furnace after the end of the heat preservation; In step S3, the Ti-Al-C composite powder accounts for 40-60% of the total molar ratio; The Ti-Al-C based conductive wear-resistant composite coating on the copper alloy surface comprises a reinforcement phase TiC phase and a TiAl phase formed by reaction, a lubricating conductive phase Ti2AlC phase formed by reaction, and unreacted conductive Ti and Cu phases.

2. The method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface according to claim 1, characterized in that: In step S1, the molar ratio of Ti powder, Al powder, and graphite powder is 2:1:1, the particle size of Ti powder is 5-30 μm, the particle size of Al powder is 3-15 μm, and the particle size of graphite powder is 1-5 μm.

3. The method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface according to claim 1, wherein: In step S1, the mass of deionized water is 1.5 times the mass of the powder, the mass of polyvinyl alcohol is 2.5% of the mass of the powder, and the mass of sodium carboxymethyl cellulose is 0.5% of the mass of the powder.

4. The method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface according to claim 1, wherein: In step S3, the Cu powder is 30-60 μm spherical powder.

5. The method for preparing a Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface according to claim 1, wherein: In step S5, the spraying parameters are as follows: current of 450-500 A, power of 30-32 kW, main gas flow rate of argon of 30-45 L / min, linear speed of 450-550 mm / s, and spraying distance of 90-110 mm.

6. A Ti-Al-C based conductive wear-resistant composite coating on a copper alloy surface prepared by the preparation method according to any one of claims 1 to 5.

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