A multi-layer structure arc erosion resistant coating based on a five-element composite system, preparation method and application thereof

Abstract

The present invention relates to the technical field of cold spraying and micro-arc oxidation surface modification, and specifically to a multilayer structure arc erosion-resistant coating based on a five-element composite system, a preparation method, and its application. The multilayer structure arc erosion-resistant coating based on the five-element composite system comprises, in sequence: a pure Cu bonding layer, a Cu-ZrN / ZrB2 transition layer, a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer, and a CuO-Al2O3-Y2O3 modified layer. The present invention solves the problems of weak load-bearing capacity and poor interlayer bonding of traditional cold spray coatings by preparing a multilayer structure coating with a dual-scale ceramic reinforcement phase. The thermal and electrical conductivity properties of the graphene@CuO / CNTs reinforcement phase are utilized, combined with micro-arc oxidation to obtain a surface modification layer, thereby improving the current-carrying wear and arc erosion performance of the multilayer structure coating while ensuring thermal and electrical conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of cold spraying and micro-arc oxidation surface modification, and in particular to a multi-layer structure arc erosion resistant coating based on a five-element composite system, a preparation method and an application thereof. Background Art

[0002] As a core component for high current carrying and sliding contact, the electromagnetic guide rail is usually made of a copper alloy with excellent conductivity (such as chromium-zirconium copper or tungsten-copper). However, the low hardness and poor arc erosion resistance of copper alloys make them face serious wear and arc erosion problems during long-term service. Traditional surface strengthening technologies such as plasma spraying and laser cladding are prone to copper substrate oxidation, grain coarsening and thermal stress cracking due to the high process temperature. Although supersonic flame spraying can produce highly dense metal ceramic wear-resistant coatings, its high-temperature flame flow will still cause thermal damage to the substrate when it acts directly on the copper alloy. In addition, since the electromagnetic guide rail is in a combined environment of high-frequency electromagnetic fields, mechanical wear and arc shock for a long time, a single material or traditional double-layer coating structure is difficult to meet the multiple functional synergistic requirements such as conductivity, wear resistance and arc erosion resistance. For example, a single conductive wear-resistant layer often has insufficient interface bonding strength due to the difference in thermal expansion coefficient with the substrate, and is prone to peeling failure under alternating electromagnetic loads; and a simple superposition structure of a conductive layer and a wear-resistant layer cannot effectively control the interlayer stress gradient, and lacks targeted protection against arc erosion.

[0003] Cold spray technology, with its low-temperature, high-speed deposition characteristics, can form a dense, adhesive transition layer on the substrate surface. This layer significantly enhances the interfacial bonding strength between the surface functional layer and the substrate through the dual effects of mechanical intercalation and metallurgical bonding of metal particles. Its gradient composition design also alleviates stress concentration between the high-hardness functional layer and the metal substrate. The addition of a self-lubricating phase and a thermally / electrically conductive reinforcing phase effectively disperses frictional heat and inhibits wear failure, ensuring the electrical contact performance of the guide rail under high-speed sliding conditions. However, metal-ceramic composite coatings can still suffer melting damage due to localized temperature rise under extreme arc conditions. Micro-arc oxidation technology is used to create a ceramic modified layer on the surface, forming a high-melting-point oxide barrier that significantly improves its resistance to arc erosion. Compared to traditional single-layer or double-layer structures, this composite system formed by combining a cold-sprayed multilayer coating with a micro-arc oxidation surface modification layer can meet the performance requirements of electromagnetic guide rail surfaces under special operating conditions. Summary of the Invention

[0004] The purpose of the present invention is to solve the problem that common coating preparation methods and single-layer / double-layer structure designs in the prior art make it difficult to prepare a protective coating on the surface of copper alloy electromagnetic guide rail materials that has high bonding strength, excellent electrical / thermal conductivity, wear resistance, and arc erosion resistance. A multi-layer structure anti-arc erosion coating based on a five-element composite system, a preparation method, and its application are provided.

[0005] In order to achieve the above objectives, the present invention discloses a multi-layer structure arc erosion resistant coating based on a five-component composite system, which includes a pure Cu bonding layer, a Cu-ZrN / ZrB2 transition layer, a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer, and a CuO-Al2O3-Y2O3 modified layer.

[0006] The thickness of the pure Cu bonding layer is 45-60 μm, the thickness of the Cu-ZrN / ZrB2 transition layer is 65-80 μm, the thickness of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer is 125-175 μm, and the thickness of the CuO-Al2O3-Y2O3 modified layer is 0.5-1 μm.

[0007] The present invention also discloses a method for preparing the multi-layer structure arc erosion resistant coating based on the five-component composite system, comprising the following steps:

[0008] S1, cold spraying pure Cu powder on the sandblasted substrate surface, spraying 1-2 times, to prepare a pure Cu bonding layer;

[0009] S2, cold spraying Cu-ZrN / ZrB2 composite powder on the surface of pure Cu bonding layer, spraying 2-3 times, to prepare Cu-ZrN / ZrB2 transition layer;

[0010] S3, cold spraying CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder on the surface of the Cu-ZrN / ZrB2 transition layer, spraying 5-8 times, to prepare a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer;

[0011] S4, micro-arc oxidation treatment is performed on the surface of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer after grinding and polishing to obtain a CuO-Al2O3-Y2O3 modified layer, and finally a multilayer structure arc erosion resistant coating based on a five-element composite system is obtained.

[0012] In step S2, the preparation method of Cu-ZrN / ZrB2 composite powder is as follows: first, the Cu and ZrB2 mixed powders are subjected to high-energy ball milling for 20 hours, and then ZrN powder is added and the ball milling is continued for 12 hours.

[0013] In step S2, the ZrN content in the Cu-ZrN / ZrB2 composite powder is 3wt.%~5wt.%, the particle size is less than 0.1μm, and the ZrB2 content is 8wt.%~15wt.%, and the particle size is 1-3μm.

[0014] In step S3, the preparation method of CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder is as follows: first, the CuCrZr and ZrB2 mixed powder is ball-milled for 20 hours, then ZrN powder is added and ball-milled for another 12 hours, and then graphene@CuO and CNTs powder are added and ball-milled for another 8 hours.

[0015] In step S3, the ZrN content in the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder is 3wt.%~5wt.%, the particle size is less than 0.1μm, the ZrB2 content is 8wt.%~15wt.%, the particle size is 1-3μm, the graphene@CuO content is 2wt.%~6wt.%, the length is 4-6μm, and the CNTs content is 1wt.%~3wt.%, and the length is 5-8μm.

[0016] In steps S1 to S3, the cold spraying parameters are as follows: nitrogen is used as the accelerating gas, the pressure is 3 MPa, the gas preheating temperature is 600° C., the spraying distance is 30 mm, the step distance is 3 mm, and the powder feeding rate is 20 g / min.

[0017] In step S4, the specific process of micro-arc oxidation treatment is as follows: the multi-layer structure coating obtained in step S3 after polishing and cleaning is immersed in the working solution as the anode, and a 316 stainless steel container is used as the cathode. A pulsed AC power supply is used to perform single-phase and then bidirectional micro-arc oxidation treatment, with a forward voltage of 400-600V, a negative voltage of 120-150V, a pulse width of 2500-3000ms, an interval of 800-1000ms, a temperature of 60-75°C, and a treatment time of 5-10min to obtain a CuO-Al2O3-Y2O3 surface modification layer; the working solution includes: KOH (4-6g / L) to provide an alkaline environment, NaAlO2 (20-40g / L) to provide Al 2+ 、 (10-15g / L) provides Cu 2+ 、Y(NO3)3(1-3g / L)provides Y 3+ , Na2SiO3 (10-14g / L) basic electrolyte, promotes the formation of Al2O3, (5-10mL / L) complexed Cu 2+ , KF (4-6g / L) improves the density of the film layer, PEG-400 (0.5-1g / L) dispersant prevents agglomeration.

[0018] The present invention also discloses the application of the multi-layer structure arc erosion resistant coating based on the five-component composite system in electromagnetic guide rails.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. Using cold-sprayed pure Cu as the bonding layer, taking advantage of its excellent plasticity and conductivity, it can form a good bond with the copper alloy substrate, effectively enhancing the interfacial bonding strength, while blocking the diffusion of matrix elements into the functional layer and maintaining the composition stability of the coating; in the Cu-ZrN / ZrB2 transition layer, Cu has a similar composition to the CuCrZr matrix in the functional layer, which can relieve interfacial thermal stress, reduce the gradient difference in thermal expansion coefficient, and reduce the risk of interlayer delamination caused by thermal cycling. In addition, the dual-scale reinforcement phases composed of nano-ZrN and micron-ZrB2 can respectively play the role of refining grains and hindering crack propagation, further enhancing the coating's resistance to crack initiation and propagation. In addition, the high hardness and high-temperature resistance of ZrN / ZrB2 can enhance the load-bearing capacity of the transition layer and provide stable support for the functional layer;

[0021] 2. In the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer, graphene@CuO / CNTs, through its high electrical conductivity and layered structure, significantly enhances the coating's thermal and electrical conductivity, effectively reducing friction interface resistance and Joule heat accumulation, and inhibiting arc erosion. Simultaneously, its dispersion-strengthening and self-lubricating properties synergistically optimize the contact state between the friction pair surfaces, reducing adhesive wear and oxidative spalling, thereby achieving low wear rate and long life under current-carrying conditions. In the CuO-Al2O3-Y2O3 surface modification layer prepared by micro-arc oxidation, Al2O3 and Y2O3 form a high-melting-point composite ceramic phase, significantly enhancing its resistance to high-temperature softening. The dispersed distribution of the conductive CuO phase promotes arc energy dissipation and inhibits localized melt pool formation. Ultimately, the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer coating exhibits excellent resistance to arc erosion and current-carrying friction and wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the SEM image of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system multilayer structure coating;

[0023] Figure 2 for Figure 1 A partial enlarged view of point A in the middle;

[0024] Figure 3 Schematic diagram of the multilayer structure coating of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system. 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] A preparation method for a multilayer structural coating based on a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system (before micro-arc oxidation) includes the following steps: first, preparing Cu-ZrN / ZrB2 powder and CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs powder by step-by-step mechanical alloying; cold spraying a pure Cu bonding layer on a CuCrZr substrate; cold spraying a Cu-ZrN / ZrB2 transition layer on the surface of the bonding layer; and cold spraying a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer on the surface of the transition layer.

[0028] The step-by-step mechanical alloying process for preparing the Cu-ZrN / ZrB2 powder comprises the following steps:

[0029] (1) First, weigh the pure Cu, ZrN, and ZrB2 powders used in the step-by-step mechanical alloying method of Cu-ZrN / ZrB2 powder. The mass ratio of Cu:ZrN:ZrB2=8.5:0.5:1 is used, and the total mass of these powders is calculated.

[0030] (2) Add the weighed Cu and ZrB2 powders into the ball mill, and add mixed grinding balls into the ball mill. The size and mass ratio of the mixed grinding balls are 15mm:10mm:6mm:5mm=1:4:2:3, and the total mass ratio of the mixed grinding balls to the total mass of the elemental powder is 10:1. Then seal the ball mill, evacuate the interior of the jar and fill it with argon. The vacuum degree must be below 10Pa, and the argon gas filled is high-purity argon with a pressure of 0.2-0.3MPa. The filling time is 15min.

[0031] (3) Place the ball mill jar in a full-scale planetary ball mill, set the ball mill speed to 220 rpm, and rotate forward for 10 minutes, stop for 2 minutes, reverse for 10 minutes, and stop for 2 minutes as one cycle. The ball milling time is 20 hours.

[0032] (4) After ball milling for 20 h, the ball mill was opened and the weighed ZrN powder was added. The ball mill was then sealed, vacuumed, and filled with argon as in step (2). The ball mill was then continued for 12 h according to the parameters of step (3).

[0033] (5) After the ball milling time is reached, Cu-ZrN / ZrB2 powder with a particle size range of 8-53 μm is screened out.

[0034] The step-by-step mechanical alloying process for preparing the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs powder comprises the following steps:

[0035] (1) First, the CuCrZr, ZrN, ZrB2 powders, graphene@CuO, and CNTs used in the step-by-step mechanical alloying method of CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs powder were weighed out. The mass ratio was CuCrZr:ZrN:ZrB2:graphene@CuO:CNTs=8:0.5:1:0.3:0.2, and the total mass of these powders was calculated.

[0036] (2) Add the weighed CuCrZr and ZrB2 powders into a ball mill, and add mixed grinding balls into the ball mill. The size and mass ratio of the mixed grinding balls are 15mm:10mm:6mm:5mm=1:4:2:3, and the total mass ratio of the mixed grinding balls to the total mass of the elemental powder is 10:1. Then seal the ball mill, evacuate the interior of the jar and fill it with argon. The vacuum degree must be below 10Pa, and the argon gas filled in is high-purity argon with a pressure of 0.2-0.3MPa. The filling time is 15min.

[0037] (3) Place the ball mill jar in a full-scale planetary ball mill, set the ball mill speed to 220 rpm, and rotate forward for 10 minutes, stop for 2 minutes, reverse for 10 minutes, and stop for 2 minutes as one cycle. The ball milling time is 20 hours.

[0038] (4) After ball milling for 20 h, the ball mill was opened and the weighed ZrN powder was added. The ball mill was then sealed, vacuumed, and filled with argon as in step (2). The ball mill was then continued for 12 h according to the parameters of step (3).

[0039] (5) After ball milling for 32 h, the ball mill was opened and weighed graphene@CuO and CNTs were added. The ball mill was then sealed, vacuumed, and filled with argon as in step (2). The ball mill was then continued for 8 h according to the parameters of step (3).

[0040] (6) After the ball milling time is reached, CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs powder with a particle size range of 8-53 μm is screened out.

[0041] The cold spraying process for preparing the pure Cu bonding layer, Cu-ZrN / ZrB2 transition layer, and CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer comprises the following steps:

[0042] (1) Pure Cu, Cu-ZrN / ZrB2, and CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs powders were dried to remove excess moisture at a temperature of 60 °C for 30 min.

[0043] (2) The surface of the CuCrZr substrate was roughened by sandblasting using 24-mesh brown corundum sand and a sandblasting carrier gas pressure of 0.2 MPa. The substrate after sandblasting was cleaned with anhydrous ethanol or acetone.

[0044] (3) Nitrogen was used as the accelerating gas, with a pressure of 3 MPa, a gas preheating temperature of 600 °C, a spraying distance of 30 mm, a step distance of 3 mm, and a powder feeding rate of 20 g / min. Two spraying passes were performed to obtain a pure Cu bonding layer with a thickness of 45-60 μm. Three spraying passes were performed to obtain a Cu-ZrN / ZrB2 transition layer with a thickness of 65-80 μm. Five spraying passes were performed to obtain a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer with a thickness of 125-175 μm.

[0045] Example 2

[0046] A method for preparing a Cu-ZrB2 transition layer comprises the following steps: firstly preparing Cu-ZrB2 powder by step-by-step mechanical alloying; and then preparing the Cu-ZrB2 transition layer by cold spraying.

[0047] The step-by-step mechanical alloying process for preparing the Cu-ZrB2 powder comprises the following steps:

[0048] (1) First, pure Cu and ZrB2 powders used in the step-by-step mechanical alloying method of Cu-ZrB2 powder were weighed out with a mass ratio of Cu:ZrB2=8.5:1.5, that is, the total ZrB2 content was 15 wt.%.

[0049] (2) Weighed Cu and ZrB2 powders (10 wt.%) were added to a ball mill. The other process steps were the same as steps 2 and 3 of the stepwise mechanical alloying preparation process of Cu-ZrN / ZrB2 powder in Example 1.

[0050] (3) After ball milling for 20 h, the ball mill was opened and the remaining ZrB2 powder (5 wt.%) was added. The other process steps were the same as steps 4 to 5 of the step-by-step mechanical alloying preparation process of Cu-ZrN / ZrB2 powder in Example 1.

[0051] The process steps in the above-mentioned cold spraying Cu-ZrN / ZrB2 transition layer preparation process are the same as the cold spraying Cu-ZrN / ZrB2 transition layer preparation process in Example 1.

[0052] The hardness and elastic modulus of the pure Cu bonding layer, Cu-ZrB2 transition layer, Cu-ZrN / ZrB2 transition layer and CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer prepared in Examples 1 and 2 were measured using a nanoindenter. The results are shown in Table 1.

[0053] Table 1 Hardness and elastic modulus of single-layer coatings

[0054]

[0055] As shown in Table 1, the hardness and elastic modulus of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer are 7.25GPa and 152.38GPa, respectively, which are significantly higher than those of the CuCrZr matrix material. This difference will significantly increase the risk of functional layer peeling. After testing, it was found that adding micron ZrB2 to Cu can increase the hardness of the coating, but reduce its elastic modulus. After adding nano ZrN, a dual-scale reinforcement phase is formed, which significantly improves the hardness and elastic modulus of the coating, and is between the pure Cu bonding layer and the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer. At the same time, the composition of the Cu-ZrN / ZrB2 transition layer is similar to that of the functional layer, which can relieve interfacial thermal stress, reduce the gradient difference in thermal expansion coefficient, and further reduce the risk of interlayer peeling caused by thermal cycling.

[0056] Example 3

[0057] The difference between this embodiment and embodiment 1 is that the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer is directly prepared on the CuCrZr substrate, and the other process steps are the same as those in embodiment 1.

[0058] Example 4

[0059] The difference between this embodiment and embodiment 1 is that a pure Cu bonding layer and a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer are directly prepared on a CuCrZr substrate, and the other process steps are the same as those in embodiment 1.

[0060] Example 5

[0061] The difference between this embodiment and embodiment 1 is that the Cu-ZrB2 transition layer and the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer are prepared directly on the CuCrZr substrate, and the other process steps are the same as those in embodiments 1 and 2.

[0062] Example 6

[0063] The difference between this embodiment and embodiment 1 is that the Cu-ZrN / ZrB2 transition layer and the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer are prepared directly on the CuCrZr substrate, and the other process steps are the same as those in embodiment 1.

[0064] The bonding strength of the single-layer, double-layer and multi-layer structure coatings prepared in Example 1 and Example 3 to Example 6 was measured using a universal testing machine, and the results are shown in Table 2. Among them, the bonding strength of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer prepared directly on the CuCrZr matrix was only 28.13MPa, and the bonding strength was significantly improved to 39.65MPa after adding the bonding layer. The bonding strength of the double-layer coating composed of the Cu-ZrB2 transition layer or the Cu-ZrN / ZrB2 transition layer and the functional layer can also improve the bonding strength of the functional layer, but is lower than the double-layer coating composed of the bonding layer and the functional layer. The bonding strength of the multi-layer structure coating composed of the bonding layer + Cu-ZrN / ZrB2 transition layer + functional layer reached a maximum of 42.95MPa, which was the most obvious improvement compared to the single-layer functional layer.

[0065] Table 2 Bonding strength of single-layer, double-layer and multi-layer coatings

[0066]

[0067] Example 7

[0068] A method for preparing a CuO-Al2O3-Y2O3 modified layer on the surface of a multilayer structure coating based on a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system by micro-arc oxidation comprises the following steps:

[0069] (1) The surface of the multilayer structure coating based on the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system is ground and polished, and the polished surface is thoroughly cleaned with anhydrous ethanol or acetone.

[0070] (2) The components of the working fluid include: KOH (4g / L) to provide an alkaline environment, NaAlO2 (25g / L) to provide Al 2+ 、 (12g / L) provides Cu 2+ 、Y(NO3)3(3g / L)provides Y 3+ , Na2SiO3 (12g / L) basic electrolyte, promotes the formation of Al2O3, (7mL / L) complexed Cu 2+ , KF (4g / L) improves the density of the film layer, and PEG-400 (0.5g / L) dispersant prevents agglomeration.

[0071] (3) The polished and cleaned multilayer structure coating was immersed in the working solution as the anode, and the 316 stainless steel container was used as the cathode. A pulsed AC power supply was used for single-phase and then bidirectional micro-arc oxidation treatment. The forward voltage was 450 V, the negative voltage was 110 V, the pulse width was 2500 ms, the pulse interval was 800 ms, the temperature was 65 ° C, and the treatment time was 8 min.

[0072] (4) Rinse the sample surface after micro-arc oxidation with deionized water to remove the residual working solution and dry it.

[0073] The performance tests of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer structure coatings before and after micro-arc oxidation prepared in Example 1 and Example 7 were carried out: the thermal conductivity of the coating was measured using a laser thermal conductivity analyzer; the resistance of the coating was measured using a comprehensive physical property measurement system; a reciprocating current-carrying friction and wear tester was used to carry out a current-carrying friction and wear test, and the specific parameters included: a load of 5N, a loading current set to 0A, 0.5A, 1A and 2A respectively, a frequency of 5Hz, a friction time of 5min, and a grinding material of GCr15 bearing steel balls with a diameter of 6mm; and a friction tester with a current-carrying friction and wear tester. Arc ablation tests were conducted according to the experimental parameters set in GB14048.4-2010. The specific parameters include: inductive load (AC-3), current 100A, voltage 400V, coil frequency 50Hz, discharge frequency 0.17Hz, air, room temperature, and the number of discharges was set to 1, 10, 100, 1000 and 2000 times respectively. A precision balance was used to evaluate the weight loss after ablation. The cross-section of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer coating after micro-arc oxidation was observed using SEM, such as Figure 1 and Figure 2 shown.

[0074] Depend on Figure 1 It can be seen that the internal structure of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite system multilayer coating is uniformly distributed, has no voids, and has good bonding at the multilayer interface. It includes a pure Cu bonding layer with a thickness of 52.3μm, a Cu-ZrN / ZrB2 transition layer with a thickness of 75.6μm, and a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer with a thickness of 143.5μm. Figure 2 This is an enlarged view near the top of the multilayer structure coating. After micro-arc oxidation, a continuous and dense CuO-Al2O3-Y2O3 modified layer is formed on the coating surface with a thickness of 0.86μm. Figure 3 Shown is a schematic diagram of the multilayer structure coating.

[0075] The thermal conductivity and resistivity of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer coating before and after surface micro-arc oxidation are shown in Table 3.

[0076] Table 3 Thermal conductivity and resistivity of coatings before and after surface micro-arc oxidation

[0077]

[0078] As shown in Table 3, the thermal conductivity and resistivity of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer coating before micro-arc oxidation are 201.43 and 201.43, respectively. and 3.83 Its thermal conductivity can reach more than 80% of the CuCrZr matrix; the thermal conductivity and electrical conductivity of the multilayer coating after micro-arc oxidation are 190.85 and 3.97 This indicates that the above steps can prepare a composite system multilayer structure coating that meets the thermal / electrical conductivity properties of the electromagnetic guide rail, and micro-arc oxidation will not have a significant effect on the thermal / electrical conductivity of the coating.

[0079] The friction coefficient and wear rate of the coating before and after surface micro-arc oxidation under different loading currents are shown in Table 4.

[0080] Table 4 Friction coefficient and wear rate of coating before and after micro-arc oxidation under different loading currents

[0081]

[0082] As shown in Table 4, the friction coefficient and wear rate of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs five-component composite multilayer coating before micro-arc oxidation are 0.616 and 10.60×10 -5 The friction coefficient and wear rate of the coating will be significantly reduced after the current is loaded. When the current is 0.5A, the friction coefficient and wear rate are 0.545 and 8.73×10 -5 With the increase of loading current, the friction coefficient and wear rate show a trend of slow increase. The friction coefficient of the multilayer structure coating after micro-arc oxidation is generally lower than that before micro-arc oxidation. Among them, the friction coefficient and wear rate are the lowest when the loading current is 0.5A, which are only 0.424 and 4.22×10 -5 Comparing the test results of different loading currents, it can be seen that the wear resistance of the multilayer coating is improved by nearly 2 times.

[0083] The coating mass and area loss before and after micro-arc oxidation under different discharge times are shown in Table 5.

[0084] Table 5 Coating mass and area loss before and after micro-arc oxidation at different discharge times

[0085]

[0086] The coating's arc erosion resistance was assessed by mass loss and area loss after different discharge cycles, as shown in Table 5. Both mass and area losses increased with the number of discharge cycles. The mass and area losses of the multilayer coating before micro-arc oxidation after 2000 discharges were 8.78% and 87.62%, respectively, while those after micro-arc oxidation were 5.32% and 62.35%, respectively. This indicates that the CuO-Al2O3-Y2O3 surface modification layer obtained by micro-arc oxidation inhibits arc erosion.

[0087] Based on the bonding strength, thermal conductivity, resistivity, current-carrying friction and wear performance tests, and arc ablation performance tests of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs quinary composite multilayer coating before and after micro-arc oxidation, the following conclusions can be drawn: The above-mentioned steps can be used to prepare a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs quinary composite multilayer coating with high bonding strength and thermal and electrical conductivity close to that of the CuCrZr substrate. In addition, micro-arc oxidation of the coating surface to obtain a CuO-Al2O3-Y2O3 surface modification layer can further enhance the arc ablation and current-carrying friction and wear performance of the multilayer coating.

[0088] 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 multi-layered arc erosion resistant coating based on a five-component composite system, characterized in that: It includes pure Cu bonding layer, Cu-ZrN / ZrB2 transition layer, CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer, and CuO-Al2O3-Y2O3 modified layer in sequence; The method for preparing the multi-layer structure arc erosion resistant coating based on the five-component composite system comprises the following steps: S1, cold spraying pure Cu powder on the sandblasted substrate surface, spraying 1-2 times, to prepare a pure Cu bonding layer; S2, cold spraying Cu-ZrN / ZrB2 composite powder on the surface of pure Cu bonding layer, spraying 2-3 times, to prepare Cu-ZrN / ZrB2 transition layer; S3, cold spraying CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder on the surface of the Cu-ZrN / ZrB2 transition layer, spraying 5-8 times, to prepare a CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer; S4, micro-arc oxidation treatment is performed on the surface of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer after grinding and polishing to obtain a CuO-Al2O3-Y2O3 modified layer, and finally a multilayer structure arc erosion resistant coating based on a five-element composite system is obtained.

2. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: The thickness of the pure Cu bonding layer is 45-60 μm, the thickness of the Cu-ZrN / ZrB2 transition layer is 65-80 μm, the thickness of the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs functional layer is 125-175 μm, and the thickness of the CuO-Al2O3-Y2O3 modified layer is 0.5-1 μm.

3. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In step S2, the preparation method of Cu-ZrN / ZrB2 composite powder is as follows: first, the Cu and ZrB2 mixed powder is ball-milled for 20 hours, and then ZrN powder is added and the ball-milling is continued for 12 hours.

4. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In step S2, the ZrN content in the Cu-ZrN / ZrB2 composite powder is 3wt.%~5wt.%, the particle size is less than 0.1μm, and the ZrB2 content is 8wt.%~15wt.%, and the particle size is 1-3μm.

5. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In step S3, the preparation method of CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder is as follows: first, the CuCrZr and ZrB2 mixed powder is ball-milled for 20 hours, then ZrN powder is added and ball-milled for another 12 hours, and then graphene@CuO and CNTs powder are added and ball-milled for another 8 hours.

6. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In step S3, the ZrN content in the CuCrZr-ZrN / ZrB2-graphene@CuO / CNTs composite powder is 3wt.%~5wt.%, the particle size is less than 0.1μm, the ZrB2 content is 8wt.%~15wt.%, the particle size is 1-3μm, the graphene@CuO content is 2wt.%~6wt.%, the length is 4-6μm, and the CNTs content is 1wt.%~3wt.%, and the length is 5-8μm.

7. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In steps S1 to S3, the cold spraying parameters are as follows: nitrogen is used as the accelerating gas, the pressure is 3 MPa, the gas preheating temperature is 600° C., the spraying distance is 30 mm, the step distance is 3 mm, and the powder feeding rate is 20 g / min.

8. The multi-layered arc erosion resistant coating based on a five-component composite system according to claim 1, characterized in that: In the step S4, the specific process of micro-arc oxidation treatment is as follows: the multilayer structure coating obtained in the polished and cleaned step S3 is immersed in the working solution as the anode, and a 316 stainless steel container is used as the cathode. A pulsed AC power supply is used to perform single-phase and then bidirectional micro-arc oxidation treatment, with a forward voltage of 400-600V, a negative voltage of 120-150V, a pulse width of 2500-3000ms, an interval of 800-1000ms, a temperature of 60-75°C, and a treatment time of 5-10min to obtain a CuO-Al2O3-Y2O3 surface modification layer; the working solution includes 4-6g / L KOH, 20-40g / L NaAlO2, 10-15g / L, 1-3g / L Y(NO3)3, 10-14g / L Na2SiO3, 5-10mL / L, and 0.5-1g / L PEG-400.

9. Use of the multi-layer anti-arc ablation coating based on the five-component composite system according to any one of claims 1 to 8 in an electromagnetic guide rail.

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