A seamless cored wire for an Al / aluminum oxide composite coating with a high friction coefficient and a preparation method thereof

Abstract

The present invention relates to the technical field of material processing engineering, and specifically to a seamless cored wire for an Al / aluminum oxide composite coating with a high friction coefficient and a preparation method thereof. The cored wire includes an outer skin and a core. The core includes aluminum alloy powder with a particle size of 15-75 μm and aluminum oxide ceramic powder with particle sizes of 15-75 μm and 350-420 μm respectively, and the total content of the aluminum oxide ceramic powder in the core is ≥ 20 wt%. The core is wrapped with industrial pure aluminum tube and obtained by rotary forging. By mixing aluminum alloy powder and multi-scale Al2O3 ceramic powder, the present invention can obtain a cored wire with high density, good thermal conductivity and good uniformity, thereby significantly improving the wear resistance of the arc spraying coating.

Description

Technical Field

[0001] The present invention relates to the technical field of material processing engineering, and particularly relates to a seamless cored wire for an Al / aluminum oxide composite coating with a high friction coefficient and a preparation method thereof. Background Art

[0002] China is rich in marine resources and has a relatively large number of marine operation equipment. The surfaces of these equipment are subject to wear and corrosion problems during long-term service in the marine environment. Surface protective coatings are one of the effective ways to improve the reliability and service life of equipment, especially key components. Therefore, surface coatings for marine environment applications should have good corrosion resistance and wear resistance. Compared with iron-based, nickel-based and other materials, aluminum-based coatings have better corrosion resistance and relatively low prices. Therefore, aluminum-based coatings are widely used in the marine field.

[0003] Due to the relatively negative potential of aluminum and the easy passivation characteristics of aluminum, pure aluminum coatings can exhibit good corrosion resistance. However, the hardness and wear resistance of pure aluminum coatings are insufficient, which limits their wide application in the field of marine wear and corrosion resistance. Aluminum-based composite coatings containing Al2O3 ceramic particles have the advantages of strong corrosion resistance, high wear resistance, etc. In particular, they enhance the friction coefficient of the coating and improve the wear resistance of the coating, and have good application prospects in the surface protection field of key equipment such as ships and offshore drilling platforms. In the preparation technology of surface protective coatings, arc spraying has the advantages of high spraying efficiency, good process controllability, simple operation, environmental friendliness, etc., and is widely used in the preparation of surface protective coatings for marine equipment.

[0004] At present, the materials used in arc spraying technology are mainly cored wires. However, most Al / Al2O3 cored wires are prepared by rolling and drawing methods, and the filling rate generally does not exceed 32%, and most of them are seamless wires. Moreover, due to the low strength and insufficient plasticity of aluminum, it is difficult to prepare Al / Al2O3 cored wires with a high Al2O3 content by rolling and drawing processes. And the cored wires prepared by rolling and drawing will have powder leakage phenomenon, resulting in a lower density of the wires, an increase in the loss during the arc spraying process, and thus a lower content of Al2O3 ceramic particles in the coating, and the friction coefficient and wear resistance of the coating are greatly limited.

[0005] In view of this, it is necessary to design an improved seamless cored wire for an Al / aluminum oxide composite coating with a high friction coefficient and a preparation method thereof to solve the above problems. Summary of the Invention

[0006] The object of the present invention is to provide a seamless cored wire for an Al / aluminum oxide composite coating with a high friction coefficient. By mixing aluminum alloy powder and multi-scale Al2O3 ceramic powder, a cored wire with high density, good thermal conductivity and good uniformity can be obtained, thereby improving the wear resistance of the arc spraying coating.

[0007] To achieve the above object, the present invention provides a seamless cored wire, including an outer skin and a core. The core includes aluminum alloy powder with a particle size in the range of 15-75 μm and alumina ceramic powder with particle sizes in the ranges of 15-75 μm and 350-420 μm respectively, and the total content of the alumina ceramic powder in the core is ≥20 wt%. By changing the content and particle size of the Al2O3 ceramic powder in the core, the density and uniformity of the core are improved, thereby effectively enhancing the spraying process of the wire and the coating performance, especially improving the wear resistance of the coating.

[0008] Preferably, the cored wire is obtained by a rotary forging process, so as to ensure a high filling rate and a high content of Al2O3 ceramic powder, thereby increasing the content of Al2O3 ceramic powder in the arc spraying coating, and the coating uniformity and density are also improved. Among them, the powder with a particle size range of 15-75 μm has no powder leakage phenomenon during the rotary forging process, and both the aluminum alloy powder and the Al2O3 ceramic powder are powders with good sphericity and good flowability, which helps to obtain a cored wire with a high filling rate, thereby increasing the content of Al2O3 ceramic powder.

[0009] Furthermore, the total content of the alumina ceramic powder in the core is 30-95 wt%, such as 38 wt%, 43 wt%, 55 wt%, 60 wt%, 70 wt%, 80 wt%, 85 wt%, etc., preferably 50-70 wt%, and more preferably 55-65%. Although the alumina ceramic powder can improve the wear resistance of the coating, when its content is too high, it is not conducive to improving the coating bonding strength. Therefore, it is necessary to ensure the content of the aluminum alloy powder at the same time, so that during the arc spraying process, the melting and bonding effect of the aluminum alloy powder is used to improve the formability of the coating and the bonding strength with the substrate.

[0010] Furthermore, the mass ratio of the alumina ceramic powder with particle sizes of 15-75 μm and 350-420 μm in the core is (0.6-1.7):1, preferably (0.8-1.2):1, and more preferably 1:1. By controlling the total content of the alumina ceramic powder and the respective contents of the two particle sizes, the density and formability of the core can be regulated, thereby realizing the optimization of the arc spraying coating performance.

[0011] Further, the filling rate of the cored wire is 40-50%, preferably 45-50%. The filling rate refers to the mass content of the powder core in the cored wire. Through rotary swaging processing, the present invention can achieve the preparation of cored wires with a high filling rate, and the loss of the powder core during the rotary swaging process is small.

[0012] Further, the aluminum alloy powder is an aluminum alloy powder with an aluminum content of 85-95 wt%, and the aluminum content is preferably 88-92 wt%; for example, AlSi10Mg powder is selected.

[0013] Preferably, the outer skin is an Al tube with a purity greater than 99.9%, such as a 1060 half-hard aluminum tube.

[0014] In some preferred embodiments, the powder core, by mass percentage, comprises the following components: 20-35% of the 15-75 μm Al2O3 ceramic powder, 20-35% of the 350-420 μm Al2O3 ceramic powder; the balance is the AlSi10Mg powder.

[0015] The present invention also provides a method for preparing a seamless cored wire, which is obtained by wrapping an industrial pure aluminum tube around a powder core and performing rotary forging. Through the rotary swaging and diameter reduction process, it helps to ensure the filling rate of the powder core, and thus ensure the content of the Al2O3 ceramic powder. Under this process, the present invention further regulates the relative content of the aluminum alloy powder and the Al2O3 ceramic powder, so as to optimize the formability and spraying processability of the cored wire, and further improve the wear resistance of the coating obtained by arc spraying.

[0016] Further, after mixing the aluminum alloy powder with a particle size of 15-75 μm and the alumina ceramic powder with particle sizes of 15-75 μm and 350-420 μm respectively evenly, it is filled into the industrial pure aluminum tube, and both ends are sealed to obtain a cored wire with an initial diameter; then the cored wire with the initial diameter is subjected to rotary forging treatment to obtain a cored wire with a diameter of 3.0 ± 0.1 mm. The small-particle-size powder can be filled into the gaps of the large-particle-size powder, and after rotary swaging, the distribution of the powder in the cored wire is more uniform and compact, further improving the density of the powder, and the coating prepared by arc spraying has a high friction coefficient. Among them, the alumina ceramic powder with particle sizes of 15-75 μm and 350-420 μm can be obtained by sieving twice to obtain the alumina ceramic powder within this range.

[0017] Further, the number of diameter reduction passes of the rotary forging is 8-14 passes; and / or, the total deformation amount of the cored wire is 90%-97%; the total deformation amount = (the cross-sectional area of the initial wire - the cross-sectional area of the final wire) / the cross-sectional area of the initial wire. Through the regulation of the number of diameter reduction passes and the deformation amount, the processability of the cored wire can be optimized.

[0018] Preferably, the commercially pure aluminum tube is an Al tube with a purity greater than 99.9%.

[0019] The present invention also provides an Al / Al2O3 composite coating, which is obtained by arc spraying using the seamless cored wire according to any one of the above, or the cored wire obtained by the preparation method according to any one of the above.

[0020] Preferably, the voltage of the arc spraying is 30 - 40V, the current is 100 - 200A, the spraying pressure is 0.4 - 0.8MPa, and the spraying distance is 100 - 200mm. Before spraying, the Q235 substrate is sandblasted and then blown clean with compressed air. The cored wire is fed into the spraying equipment, the spraying parameters are adjusted, and then spraying is carried out.

[0021] Furthermore, the friction coefficient of the Al / Al2O3 composite coating is greater than 1.30, and the friction and wear weight loss is less than 42.1×10 -4 g.

[0022] In summary, the cored wire prepared by the present invention has the advantages of high density, good thermal conductivity, good uniformity, etc. The aluminum-based coating containing Al2O3 ceramic particles prepared has the advantages of uniform composition, high friction coefficient, etc.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The seamless cored wire provided by the present invention can obtain a cored wire with high density, good thermal conductivity, and good uniformity by mixing aluminum alloy powder and multi-scale Al2O3 ceramic powder, providing favorable conditions for subsequent applications such as arc spraying.

[0025] 2. The cored wire prepared by the present invention has a high filling rate, ensuring a high content of Al2O3 ceramic powder, which is much higher than that of rolled and drawn wire with the same content.

[0026] 3. By using the cored wire obtained by the present invention for arc spraying, the obtained Al / Al2O3 composite coating has a high friction coefficient and excellent wear resistance. The dry friction coefficient of the coating exceeds 1.30, and the friction and wear weight loss is less than 42.1×10 -4 g. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1Metallographic photograph of the Al / Al2O3 composite coating prepared by arc spraying in Example 3;

[0029] Figure 2 XRD analysis pattern of the Al / Al2O3 composite coating prepared by arc spraying in Example 3. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0031] In the following embodiments, the rotary swaging machine used is produced by Xi'an Innovation Precision Instrument Research Institute.

[0032] The same parts in the following embodiments are described as follows:

[0033] 1. Preparation of seamless cored wire:

[0034] Step 1: Prepare the powder according to the formula described in the following embodiments, and mechanically mix the powder evenly. First, seal one side of the industrial pure aluminum tube, and after mixing the powder evenly, fill it into the industrial pure aluminum tube in a manner of shaking while filling. After filling, seal both ends of the industrial pure aluminum tube to obtain the cored wire with the initial diameter.

[0035] Step 2: Feed the cored wire with the initial diameter into the rotary swaging machine for diameter reduction. By controlling the number of diameter reduction passes and the deformation amount, the finally obtained cored wire has a diameter of 3.0 mm.

[0036] 2. Preparation of the coating:

[0037] Use a TLAS-400C type high-performance supersonic arc spraying equipment to prepare the coating, and the substrate of the spraying sample is Q235 steel.

[0038] Example 1

[0039] By mass percentage, the cored wire formula is: AlSi10Mg powder (15 - 75 μm): 79.7 wt%, Al2O3 ceramic powder (15 - 75 μm): 10.15 wt%, Al2O3 ceramic powder (350 - 420 μm): 10.15 wt%. Wire filling rate: 49.2%. The outer diameter of the Al tube is 10.0 mm, and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a cored wire with a diameter of 3.0 mm. Arc spraying process parameters: voltage 38 V, current 175 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0040] Example 2

[0041] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 59.6 wt%, Al2O3 ceramic powder (15 - 75 μm): 20.2 wt%, Al2O3 ceramic powder (350 - 420 μm): 20.2 wt%. Wire filling rate: 49.5%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 38 V, current 175 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0042] Example 3

[0043] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 40.0 wt%, Al2O3 ceramic powder (15 - 75 μm): 30.0 wt%, Al2O3 ceramic powder (350 - 420 μm): 30.0 wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 38 V, current 175 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0044] Example 4

[0045] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 18.50 wt%, Al2O3 ceramic powder (15 - 75 μm): 40.75 wt%, Al2O3 ceramic powder (350 - 420 μm): 40.75 wt%. Wire filling rate: 49.1%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 38 V, current 175 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0046] Example 5

[0047] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 6.4wt%, Al2O3 ceramic powder (15 - 75μm): 46.8wt%, Al2O3 ceramic powder (350 - 420μm): 46.8wt%. Wire filling rate: 48.1%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0048] Example 6

[0049] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 40.0wt%, Al2O3 ceramic powder (15 - 75μm): 30.0wt%, Al2O3 ceramic powder (350 - 420μm): 30.0wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 11.0mm and the inner diameter is 9.0mm. Rotary swaging process: 10 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0050] Example 7

[0051] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 40.0wt%, Al2O3 ceramic powder (15 - 75μm): 30.0wt%, Al2O3 ceramic powder (350 - 420μm): 30.0wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 13.0mm and the inner diameter is 8.0mm. Rotary swaging process: 12 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0052] Example 8

[0053] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 40.0wt%, Al2O3 ceramic powder (15 - 75μm): 30.0wt%, Al2O3 ceramic powder (350 - 420μm): 30.0wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 15.0mm and the inner diameter is 9.0mm. Rotary swaging process: 14 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0054] Example 9

[0055] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 40.0 wt%, Al2O3 ceramic powder (15 - 75 μm): 30.0 wt%, Al2O3 ceramic powder (350 - 420 μm): 30.0 wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 30 V, current 100 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0056] Example 10

[0057] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 40.0 wt%, Al2O3 ceramic powder (15 - 75 μm): 30.0 wt%, Al2O3 ceramic powder (350 - 420 μm): 30.0 wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 36 V, current 150 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0058] Example 11

[0059] In terms of mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75 μm): 40.0 wt%, Al2O3 ceramic powder (15 - 75 μm): 30.0 wt%, Al2O3 ceramic powder (350 - 420 μm): 30.0 wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0 mm and the inner diameter is 8.0 mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0 mm. The process parameters of arc spraying are: voltage 40 V, current 200 A, spraying pressure: 0.5 MPa, spraying distance: 150 mm.

[0060] Example 12

[0061] By mass percentage, the cored powder formula is: AlSi10Mg powder (15 - 75μm): 40.0wt%, Al2O3 ceramic powder (15 - 75μm): 22.5wt%, Al2O3 ceramic powder (350 - 420μm): 37.5wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a cored wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0062] Example 13

[0063] By mass percentage, the cored powder formula is: AlSi10Mg powder (15 - 75μm): 40.0wt%, Al2O3 ceramic powder (15 - 75μm): 37.5wt%, Al2O3 ceramic powder (350 - 420μm): 22.5wt%. Wire filling rate: 50.0%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a cored wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0064] Comparative Example 1

[0065] By mass percentage, the cored powder formula is: AlSi10Mg powder (15 - 75μm): 100wt%. Wire filling rate: 48.0%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a cored wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0066] Comparative Example 2

[0067] By mass percentage, the cored powder formula is: AlSi10Mg powder (15 - 75μm): 83.4wt%, Al2O3 ceramic powder (15 - 75μm): 4.15wt%, Al2O3 ceramic powder (350 - 420μm): 12.45wt%. Wire filling rate: 48.1%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a cored wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0068] Comparative Example 3

[0069] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 91.6wt%, Al2O3 ceramic powder (15 - 75μm): 4.2wt%, Al2O3 ceramic powder (350 - 420μm): 4.2wt%. Wire filling rate: 47.9%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0070] Comparative Example 4

[0071] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 79.04wt%, Al2O3 ceramic powder (15 - 75μm): 20.96wt%. Wire filling rate: 47.7wt%. The outer diameter of the Al tube is 10.0mm and the inner diameter is 8.0mm. Rotary swaging process: 8 passes of diameter reduction to obtain a powder core wire with a diameter of 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0072] The following comparative examples use the rolling and drawing process to prepare powder core wires:

[0073] Comparative Example 5

[0074] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 31.50wt%, Al2O3 ceramic powder (15 - 75μm): 34.25wt%, Al2O3 ceramic powder (350 - 420μm): 34.25wt%. Wire filling rate: 29.2%. Using a wire drawing die to gradually reduce the diameter by drawing, and finally the diameter of the wire is 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0075] Comparative Example 6

[0076] By mass percentage, the powder core formula is: AlSi10Mg powder (15 - 75μm): 12wt%, Al2O3 ceramic powder (15 - 75μm): 44wt%, Al2O3 ceramic powder (350 - 420μm): 44wt%. Wire filling rate: 28.4%. Using a wire drawing die to gradually reduce the diameter by drawing, and finally the diameter of the wire is 3.0mm. The process parameters of arc spraying are: voltage 38V, current 175A, spraying pressure: 0.5MPa, spraying distance: 150mm.

[0077] Metallographic observation, XRD testing and friction and wear experiments were carried out on the coatings prepared in the examples. The metallographic photos of the coatings prepared in Example 3 are as shown in Figure 1 and the XRD test results are as shown in Figure 2 . The friction coefficient and friction and wear weight loss are shown in Table 1.

[0078] The substrate of the friction and wear test specimen is a Q235 steel plate with a thickness of 10 mm, and the thickness of the coating is 600 μm. A rectangular block of 20 mm × 14 mm was cut off by wire electrical discharge machining, and then the surface of the coating was ground flat with 200#, 400#, 600#, and 800# sandpapers. A MRH-3 type high-speed ring-block friction and wear testing machine was used for the friction and wear experiments. The material of the grinding ring is GCr15, and its hardness is 60 - 62 HRC. The friction form is dry friction, the applied load is 20 N, and the experimental time is 60 min. An ME235S analytical balance was used to measure the mass of the coating before and after the experiment, and the mass difference of the coating before and after friction and wear was used as a parameter to evaluate the wear resistance of the coating. The results of the coating friction coefficient and friction and wear weight loss are shown in Table 1.

[0079] Table 1 Test results of the coating friction coefficient and friction and wear weight loss of the examples and comparative examples (the total content of Al2O3 ceramic powder in the wire is calculated including the powder core and the outer skin)

[0080]

[0081]

[0082] As can be seen from Table 1, by mixing aluminum alloy powder and multi-scale Al2O3 ceramic powder, after the obtained powder core wire is arc sprayed, the dry friction coefficient of the coating is significantly increased, and the friction and wear weight loss is significantly reduced. Among them, when the total content of Al2O3 ceramic powder in the wire of Example 3 is 30 wt% and the filling rate is 50%, the comprehensive performance of the coating is the best. When there is no Al2O3 ceramic powder in the powder core of Comparative Example 1, the dry friction coefficient is significantly reduced, and the friction and wear weight loss is as high as 110.56×10 -4 g. It can be seen that the Al2O3 ceramic powder is crucial for improving the wear resistance of the coating. The total content of Al2O3 ceramic powder in Comparative Examples 2 and 3 is less than 10 wt%, and the wear resistance is still lower than that of the examples. In Comparative Example 4, when only Al2O3 ceramic powder (15 - 75 μm) is contained, the wear resistance is also lower than that of the examples, indicating that the combined use of Al2O3 ceramic powders with different particle sizes also has a great influence on the wear resistance of the coating. Comparative Examples 5 and 6 adopt the drawing process, and both the filling rate and wear resistance are lower than those of the examples.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A seamless cored wire, comprising an outer skin and a core, characterized in that, The cored powder includes aluminum alloy powder with a particle size of 15 - 75 μm and alumina ceramic powder with particle sizes of 15 - 75 μm and 350 - 420 μm respectively, and the total content of alumina ceramic powder in the cored powder is ≥ 20 wt%; The method for preparing the seamless cored wire is rotary forging; The friction coefficient of the Al / Al2O3 composite coating obtained by arc spraying of the seamless cored wire is greater than 1.30, and the friction and wear weight loss is less than 42.1×10 -4 g.

2. The seamless cored wire according to claim 1, characterized in that, The total content of alumina ceramic powder in the cored powder is 50 - 70 wt%; 3. The seamless cored wire according to claim 2, wherein The mass ratio of the alumina ceramic powder with particle sizes of 15 - 75 μm and 350 - 420 μm in the cored powder is 1:1; 4. The seamless cored wire according to any one of claims 1-3, characterized in that, The filling rate of the cored wire is 48.1 - 50%; 5. The seamless cored wire according to any one of claims 1-4, characterized in that, The aluminum alloy powder is an aluminum alloy powder with an aluminum content of 88 - 92 wt%; And / or, the outer skin is an Al tube with a purity greater than 99.9%; 6. The preparation method of the seamless cored wire according to any one of claims 1-5, characterized in that, It is obtained by wrapping the cored powder with an industrial pure aluminum tube and performing rotary forging; 7. The preparation method of the seamless cored wire according to claim 6, characterized in that, The aluminum alloy powder with a particle size of 15 - 75 μm and the alumina ceramic powder with particle sizes of 15 - 75 μm and 350 - 420 μm are filled into the industrial pure aluminum tube. After sealing both ends, rotary forging treatment is carried out to obtain a seamless cored wire with a diameter of 3.0 ± 0.1 mm; 8. The method for preparing a seamless cored wire according to claim 6 or 7, characterized in that, The number of diameter reduction passes of the rotary forging is 8 - 14 passes; and / or, the total deformation amount of the cored wire is 90% - 97%; The industrial pure aluminum tube is an Al tube with a purity greater than 99.9%; 9. An Al / Al2O3 composite coating, characterized in that, It is obtained by arc spraying the seamless cored wire described in any one of claims 1 - 5 or the seamless cored wire obtained by the preparation method described in any one of claims 6 - 8; 10. The Al / Al2O3 composite coating according to claim 9, wherein The voltage of the arc spraying is 30 - 40 V, the current is 100 - 200 A, the spraying pressure is 0.4 - 0.8 MPa, and the spraying distance is 100 - 200 mm.

Images