High-corrosion-resistance cold spraying Zn-Al-Ta ternary composite coating material and spraying method

Abstract

The invention discloses a cold spraying Zn-Al-Ta ternary composite coating material with high corrosion resistance and a spraying method, and the material comprises three metal powders of Zn, Al and Ta: 15-35 wt% of the Al powder, 15 wt% of the Ta powder, and the balance of the Zn powder. A metal matrix is pretreated firstly, and cold spraying process parameters are as follows: both powder feeding gas and working gas are compressed N2, the gas pressure is 0.8-1.2 MPa, the gas heating temperature is 350-410 DEG C, the powder feeding amount is 40-60 g / min, the cold spraying distance is 15-25 mm, and the relative movement speed is 5-10 mm / s. The sacrificial anode properties of Zn and Al and the extreme corrosion resistance of Ta are combined, Zn and Al can form a more compact corrosion product, Ta can effectively'pin 'the corrosion product, the loss rate of the corrosion product is reduced, the corrosion resistance of the coating is improved, and the service life of the coating is prolonged.

Description

TECHNICAL FIELD

[0001] The application relates to the field of cold spraying technology, in particular to a high-corrosion-resistance cold-sprayed Zn-Al-Ta ternary composite coating material and a spraying method. BACKGROUND

[0002] Magnesium alloy is an extremely common light metal material, and magnesium alloy is limited in wide application due to insufficient corrosion resistance. In addition to modifying the components of the material itself, preparing a corrosion-resistant protective coating on the surface of the magnesium alloy is a more common choice for improving the corrosion resistance of the magnesium alloy. The coating preparation methods include plasma spraying, arc spraying, flame spraying and the like. Although these technologies can realize coating deposition, these technologies are complicated to operate and high in cost, and more importantly, thermal stress is inevitably introduced in the high-temperature processing process, which can cause oxidation phase change of oxygen-sensitive and heat-sensitive materials and change the original components of the coating.

[0003] Cold spraying is an emerging coating deposition technology, which mainly uses high-temperature and high-pressure gas to wrap raw material powder to impact the substrate to realize coating deposition through plastic deformation. Compared with other spraying technologies, cold spraying has a lower processing temperature, and the temperature of the powder raw material is always lower than the melting point of the powder during the spraying process, which is very friendly to some temperature- and oxygen-sensitive materials and has obvious advantages in the coating protection field.

[0004] Metal Zn has a wide application in the fields of electricity, chemical industry and marine ships due to the excellent cathodic protection effect of the sacrificial anode and relatively dense corrosion products. However, under the condition of long service time, Zn will be consumed, and defects will appear in some positions due to the loss of Zn, thereby affecting the service life of the workpiece. The existing solutions mainly reflect the optimization of the components of the Zn coating. The common added phases of the Zn coating include pure metal phases such as Al, Ni and Sn and ceramic phases such as Al2O3, HA (hydroxyapatite) and h-BN (hexagonal boron nitride). The addition of the metal phase generally improves the corrosion resistance of the coating by improving the coating density and obtaining more dense corrosion products.

[0005] Al has similar chemical properties to Zn, and Zn-Al composite coating has also been subjected to a large amount of experiments and research in recent years. The addition of Al makes the corrosion product Zn6Al2(OH) 16CO3·4H2O, the protective effect is better. At the same time, Ta can effectively improve the protective effect of pure Zn coating because of its high corrosion resistance, which can effectively pin the corrosion product and prevent the dense corrosion product from falling off. However, both Zn-Al coating and Zn-Ta coating have the problem of less corrosion product coverage area, and pitting and other problems are prone to occur during the corrosion process. The corrosion protection effect under extreme working conditions cannot meet the requirements, the coating loss rate is still too fast, and the economic benefit is not high. This shows that the corrosion resistance of the two coatings still has a large room for improvement. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a cold sprayed Zn-Al-Ta ternary composite coating material with high corrosion resistance and a spraying method. The ternary composite coating prepared by the method has good corrosion resistance and service life, and solves the problems of unsatisfactory corrosion resistance effect, poor corrosion resistance and short service life of the existing metal substrate surface.

[0007] The present application is realized by the following technical solutions.

[0008] The cold sprayed Zn-Al-Ta ternary composite coating material with high corrosion resistance comprises Zn, Al and Ta three kinds of metal powders: the mass percentage of Al powder is 15% to 35%, the mass percentage of Ta powder is 15%, and the balance is Zn powder.

[0009] The particle size of the Zn powder and the Al powder is 5 to 50 microns, the particle size of the Ta powder is 5 to 80 microns, and the shape can be spherical or irregular.

[0010] The mixing method of the Zn, Al and Ta powders is mechanical ball milling, and the parameters of the planetary ball mill are as follows: the rotation speed is 120 to 200 rpm, the mixing time is 2 to 3 hours, the ball-to-material ratio is 5:1, and the grinding ball material is any one of Al2O3 and ZrO2.

[0011] A spraying method of a cold sprayed Zn-Al-Ta ternary composite coating with high corrosion resistance, the pretreatment step before spraying the metal substrate: the surface of the metal substrate is cleaned with acetone and dried, and then sandblasting treatment is carried out, 6# corundum sand is used for sandblasting, and the surface oxide layer is removed and the roughness is increased to 1.0 to 3.0 microns under the condition of compressed air pressure of 0.4 MPa.

[0012] The cold spraying process parameters are as follows: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 0.8-1.2 MPa, the gas heating temperature is 350-410 DEG C, the powder feeding amount is 40-60 g / min, the distance between the spray gun and the substrate surface during the cold spraying is 15-25 mm, and the relative moving speed between the spray gun and the substrate is 5-10 mm / s.

[0013] The thickness of the Zn-Al-Ta ternary composite coating is greater than 150 microns.

[0014] The metal substrate is any one of a steel material and a magnesium alloy substrate.

[0015] The technical effects of the present application are as follows:

[0016] (1) The Zn-Al-Ta coating designed in the present application is a ternary composite coating, wherein Zn and Al have the property of sacrificial anode, and both of them can generate corrosion product Zn6Al2(OH) 16 CO3·4H2O in the corrosion process, which is a hydrotalcite structure, is more compact and less soluble than Zn5(OH)8Cl2·H2O and Zn(OH)2 commonly found in pure Zn coating, and Ta, as an extremely corrosion-resistant material, generates Ta2O5 in the corrosion environment, which has extremely high corrosion resistance and can effectively "pin" the corrosion products of Zn and Al, reduce the overall loss rate of the corrosion products, and thus prolong the existence time of the passivation layer of the corrosion products on the coating surface. Therefore, the coating obtained by the method of the present application can better prevent the substrate from being corroded and improve the service life of the metal substrate.

[0017] (2) The corrosion current density of the Zn-Al-Ta coating obtained by the present application is significantly lower than that of pure Zn coating and Zn-Al composite coating, which is 1 / 6 of that of pure Zn coating and 1 / 2 of that of Zn-Al composite coating. According to Faraday's law, this indicates that the less oxidation reaction occurs per unit time, the better the corrosion resistance.

[0018] (3) The three kinds of metal powders used in the present application will produce diffusion effect among each other during mechanical ball milling and cold spraying, which is reflected in the strengthening of the deposited particle boundary in the coating, and the Ta element diffuses to other metal powders, so that the influence range is further enhanced.

[0019] (4) The Al powder with an addition amount of less than 35 wt.% used in the present application can avoid the enrichment of Al particles in the coating. The expansion stress generated by the enriched Al corrosion products will directly cause the interlayer separation of the coating in local areas, and thus lead to premature failure. Therefore, the powder ratio used is reasonable, and the corrosion resistance of the coating is improved.

[0020] (5) The target coating is prepared by the cold spraying process method, and the process is simple. The spraying temperature is low, so that the heat input of the substrate and the powder is avoided. The powder gas and the working gas are compressed N2, which effectively avoids the adverse effects of oxidation and phase change of the coating, and ensures the uniformity of the composition and performance of the powder and the coating.

[0021] (6) The mass ratio of the mixed powder is very reasonable. After trying various ratios, it is found that the ratio in the application can ensure the deposition efficiency of the powder, and then under the condition of considering the raw material cost, the final coating has a relatively thick thickness, which can meet the requirements of corrosion-resistant coating. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a morphology diagram of Zn, Al and Ta composite powder.

[0023] Figure 2 The figure is a particle size distribution diagram of three original powders of Zn, Al and Ta. Among them, Volume is the total amount, Patical size is the particle size, Gauss fit is Gaussian fitting, and Size distribution is particle size distribution.

[0024] Figure 3 The figure is an XRD phase diagram of pure Zn, Zn-Al and Zn-Al-Ta composite coatings and raw powders. Among them, A: 70wt.% Zn-15wt.% Al-15wt.% Ta; B: 60wt.% Zn-25wt.% Al-15wt.% Ta; C: 50wt.% Zn-35wt.% Al-15wt.% Ta; D: 60wt.% Zn-40wt.% Al; E: pure Zn; Intensity: intensity; 2Theta: 2Θ

[0025] Figure 4 The figure is a cross-sectional morphology diagram of pure Zn, Zn-Al and Zn-Al-Ta composite coatings.

[0026] Figure 5 The figure is an impedance diagram of pure Zn, Zn-Al and Zn-Al-Ta composite coatings in a 3.5 wt.% NaCl solution at room temperature. Among them, Z'' is the imaginary part of impedance, and Z is the real part of impedance.

[0027] Figure 6 The figure is a polarization curve diagram of pure Zn, Zn-Al and Zn-Al-Ta composite coatings in a 3.5 wt.% NaCl solution at room temperature. Among them, Potential is the potential, and Current is the current.

[0028] Figure 7XRD results of surface corrosion products of pure Zn, Zn-Al and Zn-Al-Ta composite coatings after 10 days of salt spray corrosion in 3.5 wt.% NaCl at 35℃.

[0029] Figure 8 EDS line scanning spectrum of Zn and Ta diffusion phenomenon in Zn-Al-Ta composite coating. Wherein, Count-total number; Distance-distance; Scanning direction-scanning direction; Fit denoising-fitting denoising.

[0030] Figure 9 Coating cross-section of Zn-Al and Zn-Al-Ta composite coatings after 30 days of salt spray corrosion in 3.5 wt.% NaCl at 35℃. DETAILED DESCRIPTION

[0031] The present application will be further described by examples in conjunction with the accompanying drawings.

[0032] Raw material sources:

[0033] In the specific embodiment, the raw powder material selected by the present application is: Zn and Al metal powder with a powder particle size of 5-50 μm, a purity of 99.9%, and a powder particle shape of spherical or irregular shape; Ta metal powder with a powder particle size of 5-80 μm, a purity of 99.9%, and a powder particle shape of spherical or irregular shape.

[0034] The substrate is AZ31B magnesium alloy with a thickness of 5 mm.

[0035] The raw materials not specifically described in the examples and comparative examples are all commercially available products.

[0036] The steps not described in detail in the examples and comparative examples are carried out by using the conventional processes in the technical field.

[0037] Example 1

[0038] The present embodiment provides a high corrosion-resistant cold sprayed Zn-Al-Ta ternary composite coating material and a spraying method, comprising the following steps:

[0039] S1, mixing different gradations of Zn, Al and Ta powders; weighing 50% by weight of spherical or irregularly shaped Zn powder with a particle size of 5-50 pm, 35% by weight of spherical or irregularly shaped Al powder with a particle size of 5-50 pm, and 15% by weight of spherical or irregularly shaped Ta powder with a particle size of 5-80 pm into a planetary ball mill, the rotation speed of the ball mill is 120-200 rpm, the mixing time is 2-3 h, the ball-to-material ratio is 5:1, and any one of Al2O3 and ZrO2 is used as the ball mill material.

[0040] S2, pretreating the surface of the substrate; before spraying, the surface of the metal substrate is cleaned with acetone and dried, and then sandblasting is performed, 6# corundum sand is used for sandblasting, and the compressed air pressure is 0.4 MPa to remove the surface oxide layer and increase the roughness to 1.0-3.0 pm.

[0041] S3, cold spraying, the mixed powder after mechanical ball milling in step S1 is cold sprayed onto the pretreated substrate surface in step S2, and the cold spraying process parameters are as follows: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 0.8 MPa, the gas heating temperature is 350°C, the powder feeding amount is 40 g / min, the distance between the spray gun and the substrate surface during cold spraying is 15 mm, and the relative movement speed between the spray gun and the substrate is 6 mm / s.

[0042] Example 2

[0043] The embodiment provides a cold sprayed Zn-Al-Ta ternary composite coating material with high corrosion resistance and a spraying method, which comprises the following steps:

[0044] S1, mixing different gradations of Zn, Al and Ta powders; weighing 60% by weight of spherical or irregularly shaped Zn powder with a particle size of 5-50 pm, 25% by weight of spherical or irregularly shaped Al powder with a particle size of 5-50 pm, and 15% by weight of spherical or irregularly shaped Ta powder with a particle size of 5-80 pm into a planetary ball mill, the rotation speed of the ball mill is 120-200 rpm, the mixing time is 2-3 h, the ball-to-material ratio is 5:1, and any one of Al2O3 and ZrO2 is used as the ball mill material.

[0045] S2, pretreating the surface of the substrate; before spraying, the surface of the metal substrate is cleaned with acetone and dried, and then sandblasting is performed, 6# corundum sand is used for sandblasting, and the compressed air pressure is 0.4 MPa to remove the surface oxide layer and increase the roughness to 1.0-3.0 pm.

[0046] S3, cold spraying, the mixed powder after mechanical ball milling in step S1 is cold sprayed to the substrate surface pretreated in step S2, the cold spraying process parameters are: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 0.8 MPa, the gas heating temperature is 400℃, the powder feeding amount is 50g / min, the distance between the spray gun and the substrate surface during cold spraying is 20mm, and the relative moving speed between the spray gun and the substrate is 6mm / s.

[0047] Example 3

[0048] The embodiment provides a cold sprayed Zn-Al-Ta ternary composite coating material with high corrosion resistance and a spraying method, which comprises the following steps:

[0049] S1, mixing different gradations of Zn, Al and Ta powders; 70wt% of spherical or irregularly shaped Zn powder with a particle size of 5-50μm, 15wt% of spherical or irregularly shaped Al powder with a particle size of 5-50μm and 15wt% of spherical or irregularly shaped Ta powder with a particle size of 5-80μm are weighed and put into a planetary ball mill, the rotation speed of the ball mill is 120-200rpm, the mixing time is 2-3h, the ball-to-material ratio is 5:1, and any one of Al2O3 and ZrO2 is used as the ball mill material.

[0050] S2, pretreating the substrate surface; the metal substrate surface is cleaned with acetone and dried before spraying, and then sand blasting is performed, 6# corundum sand is used, and the compressed air pressure is 0.4MPa, so as to remove the surface oxide layer and increase the roughness to 1.0-3.0μm.

[0051] S3, cold spraying, the mixed powder after mechanical ball milling in step S1 is cold sprayed to the substrate surface pretreated in step S2, the cold spraying process parameters are: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 1.2 MPa, the gas heating temperature is 410℃, the powder feeding amount is 60g / min, the distance between the spray gun and the substrate surface during cold spraying is 25mm, and the relative moving speed between the spray gun and the substrate is 10mm / s.

[0052] Comparative Example 1

[0053] The comparative example provides a preparation method of a cold sprayed pure Zn coating, which comprises the following steps:

[0054] S1, simply screening spherical or irregularly shaped pure Zn powder with a particle size of 5-50μm to enhance the flowability for facilitating spraying.

[0055] S2, pretreatment of the substrate surface; before spraying, the metal substrate surface is cleaned with acetone and dried, then sandblasting is performed, sandblasting uses No. 6 corundum sand, and the surface oxide layer is removed and the roughness is increased to 1.0-3.0 μm under the condition of compressed air pressure of 0.4 MPa.

[0056] S3, cold spraying, the pure Zn powder in step S1 is cold sprayed onto the pretreated substrate surface in step S2, and the cold spraying process parameters are as follows: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 0.8 MPa, the gas heating temperature is 400℃, the powder feeding amount is 50 g / min, the distance between the spray gun and the substrate surface during cold spraying is 20 mm, and the relative moving speed between the spray gun and the substrate is 6 mm / s.

[0057] Comparative Example 2

[0058] The present comparative example provides a preparation method of a cold sprayed Zn-Al composite coating, comprising the following steps:

[0059] S1, mixing of Zn and Al powders with different gradations; the spherical or irregularly shaped Zn powder with a particle size of 5-50 μm in a weight percentage of 60% and the spherical or irregularly shaped Al powder with a particle size of 5-50 μm in a weight percentage of 40% are weighed and added into a planetary ball mill, the ball mill speed is 120-200 rpm, the mixing time is 2-3 h, the ball-to-material ratio is 5:1, and any one of Al2O3 and ZrO2 is used as the grinding ball material.

[0060] S2, pretreatment of the substrate surface; before spraying, the metal substrate surface is cleaned with acetone and dried, then sandblasting is performed, sandblasting uses No. 6 corundum sand, and the surface oxide layer is removed and the roughness is increased to 1.0-3.0 μm under the condition of compressed air pressure of 0.4 MPa.

[0061] S3, cold spraying, the mixed powder after mechanical ball milling in step S1 is cold sprayed onto the pretreated substrate surface in step S2, and the cold spraying process parameters are as follows: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 1.2 MPa, the gas heating temperature is 410℃, the powder feeding amount is 60 g / min, the distance between the spray gun and the substrate surface during cold spraying is 25 mm, and the relative moving speed between the spray gun and the substrate is 10 mm / s.

[0062] The powders used in Examples 1-3 and Comparative Examples 1 and 2 are subjected to EDS testing and laser particle size testing to determine the uniformity and particle size distribution of the mixed powders, the coatings of Examples 1-3 and Comparative Examples 1 and 2 are subjected to cross-sectional SEM scanning, XRD phase testing and electrochemical performance experiments, the coating compactness and composition consistency are observed, and their corrosion resistance is tested.

[0063] Experimental Example 1 Powder SEM characterization

[0064] The mixed powder was tested by energy dispersive X-ray spectroscopy (EDS) using a field emission electron microscope. The main elements were Zn, Al, and Ta. The scanning results are shown in Figure 1 .

[0065] Experimental Example 2 Powder laser particle size test

[0066] The raw material powder was placed in a laser particle size analyzer, and the dispersant was anhydrous ethanol. The test results are shown in Figure 2 .

[0067] Experimental Example 3 3.5 wt.% NaCl salt spray corrosion test under 35°C conditions

[0068] The neutral salt spray corrosion test was performed according to the GB / T 10125-2021 standard. The inlaid surface sample was ground to 2000 mesh to ensure that the surface roughness was less than 1 μm. To avoid premature failure of the sample due to poor sealing of the edge part in contact with the epoxy resin, the sample was inlaid along the edge gap of the sample inlaid and sealed again by applying epoxy resin. After the epoxy resin solidified, the sample was placed at an angle of 70° to the horizontal in a salt spray chamber (HJ-YW90Y, 2 kW, 50 Hz) for salt spray corrosion testing. The salt spray solution was 3.5 wt.% NaCl solution, and the corrosion environment temperature was 35±1 ℃. Each coating sample was placed in 3 samples to ensure the reliability of the salt spray corrosion results. To test the long-term corrosion resistance of the coating, the corrosion time gradient was set to 10 days and 30 days, referring to the recommended duration of the experimental standard. After reaching the corrosion time, the sample was taken out and slowly rinsed with room temperature deionized water to remove the surface residual salt, and then dried.

[0069] Experimental Example 4 XRD phase characterization

[0070] The coating, raw material powder, and coating surface after 10 days of salt spray corrosion obtained from Examples 1-3 and Comparative Examples 1 and 2 were characterized using an X-ray diffractometer. The scanning range was set to 3° to 90°, the step size was 0.02°, the working current was 40 mA, the voltage was 40 kV, and a Cu-alpha target was used. The characterization results are shown in Figure 3 and Figure 7 .

[0071] Experimental Example 5 SEM and EDS line scanning of coating cross-section before and after corrosion

[0072] The coatings obtained in Examples 1-3 and Comparative Examples 1 and 2 were metallographically polished and characterized using field emission electron microscopy (FET) to observe their thickness and density. EDS line scans were performed on the Zn-Ta powder interface in Examples 1-3 using the EDS module of the SEM to observe diffusion. The cross-sections of the coatings from Examples 1-3 and Comparative Example 2 after 30 days of salt spray corrosion were also metallographically polished and characterized to observe corrosion conditions. The SEM scan results are shown below. Figure 4 and Figure 9 EDS line scan results are shown below. Figure 8 .

[0073] Experiment Example 6: Electrochemical Performance Testing

[0074] Electrochemical tests of the three-electrode system were conducted using a Chenhua electrochemical workstation (CHI760e). The test solution was 3.5 wt.% NaCl solution, and the test temperature was room temperature (25 ℃). The reference electrode was a saturated calomel electrode, the auxiliary electrode was a platinum sheet, and the working electrode was the coated sample. The substrate bottom surface was connected to the workstation, and the coating surface was exposed to the solution for testing. To ensure the accuracy of the test results, impedance and polarization curve measurements were performed after the open-circuit potential had stabilized (fluctuation <0.1 V). The electrochemical impedance spectroscopy frequency range was 0.01 Hz to 100,000 Hz, and the polarization curve scan rate was 0.01 V / s. The self-corrosion current density measured by the polarization curve was then calculated using Faraday's law. The test results are shown below. Figure 5 (Impedance spectrum) Figure 6 (Polarization curves) and Table 1 (Polarization curve data).

[0075] Table 1. Polarization curve test data of pure Zn and Zn-Al-Ta composite coatings in 3.5 wt.% NaCl solution at room temperature.

[0076]

[0077] from Figure 1 As can be seen, the Zn, Al, and Ta powders can be fully and uniformly mixed using the ball milling method, ensuring the uniformity of the composition in the coating.

[0078] from Figure 2 As can be seen, the Zn, Al, and Ta powders are all within the required range, and the powder particle size meets the particle size requirements of conventional cold spray powders, ensuring high deposition efficiency and low economic cost required to form a coating.

[0079] from Figure 3 As can be seen, the raw material powder and the coating after spraying have the same phase, indicating that the N2 gas and cold spraying parameters used ensure that the metal powder does not undergo oxidation or phase change during the spraying process.

[0080] From Figure 4 It can be seen from the above that the coating porosities of Examples 1-3 and Comparative Examples 1 and 2 are all very low, indicating that the cold spraying parameters adopted can ensure the deposition effect of the coating and obtain a dense coating.

[0081] From Figure 5 and Figure 6 It can be seen from the above that only the type and content of the raw material powder are changed in Example 2 compared with Comparative Example 1, and the open circuit potential of the coating obtained after adding a certain content of Al powder to the pure Zn powder is obviously improved, the circular arc radius in the impedance diagram is obviously larger, and the passivation of the polarization curve is more obvious. It is indicated that the corrosion resistance is obviously improved, and the corrosion resistance of the ternary composite coating obtained after further adding Ta powder is significantly improved.

[0082] From Figure 7 It can be seen from the XRD results of the coating samples of Comparative Examples 1-3 and Comparative Example 2 after salt spray corrosion for 10 days that the characteristic peaks of Zn5(OH)8Cl2·H2O are obviously observed in the Ta-containing coating, which indicates that the addition of Ta effectively “pins” the corrosion products such as Zn5(OH)8Cl2·H2O. The retention time of the passivation layer of the corrosion products on the surface of the coating is effectively prolonged, and the corrosion resistance of the coating is significantly improved.

[0083] From Figure 8 It can be seen from the above that there is an obvious diffusion phenomenon between Ta and Zn in Examples 1-3, and the diffusion range reaches 0.3 μm. It is indicated that the influence of Ta in the coating can be further expanded by the spraying method of the present application, and the relatively weak particle boundary position is effectively protected.

[0084] From Figure 9 It can be seen from the coating cross sections of Comparative Examples 1-3 and Comparative Example 2 after corrosion for 30 days that a large number of long cracks appear in the coatings of Example 1 and Comparative Example 2 with high Al content, and the starting position is the Al-rich region. The expansion stress caused by the aggregation of a large amount of corrosion products leads to cracking of the coating, while the coatings of Example 2 and Example 3 do not have this situation and are still very dense after corrosion. It is indicated that a lower Al content helps to avoid premature failure of the coating.

[0085] It can be seen from Table 1 that the corrosion current density of the obtained Zn-Al-Ta ternary composite coating is obviously lower compared with Comparative Example 1 and Comparative Example 2, and the corrosion current density is reduced to about 1 / 6 of the pure Zn coating and about 1 / 2 of the Zn-Al composite coating. It is indicated that the electronic exchange efficiency in the corrosion process is lower, and the corrosion resistance is significantly improved.

[0086] The above merely illustrates the preferred embodiments of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A high corrosion resistant cold sprayed Zn-Al-Ta ternary composite coating material, characterized in that The three metal powders include Zn, Al and Ta, wherein the mass percentage of the Al powder is 15-35%, the mass percentage of the Ta powder is 15%, and the rest is Zn powder; The particle size of the Zn powder and the Al powder is 5-50 μm, and the particle size of the Ta powder is 5-80 μm.

2. The method for spraying the high corrosion resistant cold sprayed Zn-Al-Ta ternary composite coating of claim 1, characterized in that First, the surface of the metal matrix is cleaned with acetone and dried, and then sand blasting is performed, wherein the sand blasting uses No. 6 corundum sand, and the compressed air pressure is 0.4 MPa, so as to remove the surface oxide layer and increase the roughness to 1.0-3.0 μm; The cold spraying process parameters are as follows: the powder feeding gas and the working gas are both compressed N2, the gas pressure is 0.8-1.2 MPa, the gas heating temperature is 350-410 ℃, the powder feeding amount is 40-60 g / min, the distance between the spray gun and the matrix surface during the cold spraying is 15-25 mm, and the relative moving speed between the spray gun and the matrix is 5-10 mm / s; The thickness of the Zn-Al-Ta ternary composite coating is greater than 150 μm; The metal matrix is any one of a steel material and a magnesium alloy matrix.

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