A method for preparing an aluminum alloy drill pipe surface with a high wear-resistant and corrosion-resistant aluminum-based amorphous coating

Abstract

This invention relates to a method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of aluminum alloy drill pipes, belonging to the field of drilling engineering technology. The method utilizes a low-temperature supersonic flame spraying method to coat aluminum-based amorphous powder onto the surface of the aluminum alloy drill pipe, forming an aluminum-based amorphous coating. The process parameters for the low-temperature supersonic flame spraying are: the sum of the total flow rates of propylene and oxygen is 0.004370–0.013110 kg / s, the oxygen-fuel ratio is 2.0–4.0, the flow rate of cooling nitrogen is 0.003678–0.011034 kg / s, the powder injection angle is -45°–45°, the powder injection speed is 5–25 m / s, and the powder spraying distance is 120–160 mm. This invention utilizes low-temperature supersonic flame spraying technology to coat the surface of the aluminum alloy drill pipe with aluminum-based amorphous alloy in the form of powder particles, forming an aluminum-based amorphous alloy coating.

Description

Technical Field

[0001] This invention relates to a method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of aluminum alloy drill pipes, belonging to the field of drilling engineering technology. Background Technology

[0002] With the exploration and development of deep oil and gas resources, a large number of complex and special wells, such as ultra-deep wells, extended reach wells, and wells in high-temperature, high-pressure, and highly corrosive media, have emerged. This has continuously placed new demands on exploration and development equipment and technologies, especially on drill pipes. In the drilling process of deep oil and gas wells, aluminum alloy drill pipes are widely used due to their advantages such as low density, non-magnetic properties, high specific strength, strong impact resistance, and insensitivity to hydrogen sulfide stress corrosion. However, under long-term exposure to complex working conditions, the inherent disadvantages of aluminum alloy drill pipes, such as low hardness, easy wear, poor high-temperature mechanical properties, and poor resistance to salt corrosion, have gradually become apparent. These disadvantages easily lead to failure modes such as scratches, wear, corrosion, and fracture during drilling, which seriously affects the normal use of aluminum alloy drill pipes and greatly reduces their service life.

[0003] Currently, the main technology for preparing films on the surface of aluminum alloy drill pipes is micro-arc oxidation (MAO). MAO, also known as micro-plasma oxidation or anodic spark deposition, is a new technology that uses micro-plasma discharge to grow oxide ceramic films in situ on the surface of light alloys through complex electrochemical, plasma chemical, and thermochemical processes. Films formed on aluminum alloy drill pipes using this technology exhibit high bonding strength with the substrate, high hardness, good wear resistance, and strong thermal shock resistance. However, aluminum alloy drill pipes operate for extended periods in deep wells, ultra-deep wells, and oil and gas wells containing hydrogen sulfide and carbon dioxide. Facing high temperatures, high wear, and salt corrosion, the performance of films prepared by MAO is not yet strong enough. The high coefficient of friction may lead to a decline in the mechanical properties of the film, resulting in peeling and wear-through within a short period. Therefore, there is a need to find a new technology or method to improve the hardness, wear resistance, and corrosion resistance of aluminum alloy drill pipes, and extend their service life under complex working conditions.

[0004] With the continuous advancement of science and technology, amorphous alloys have become a focus of attention for scholars both domestically and internationally due to their unique disordered structure and excellent mechanical, physical, and chemical properties. Among them, aluminum-based amorphous alloys stand out from other amorphous alloys due to their high strength, high toughness, superplasticity, and excellent corrosion and wear resistance, among other advantages. They are widely used in surface corrosion protection in fields such as energy and chemical engineering, marine equipment, and aerospace. Typically, aluminum-based amorphous alloys are produced in the form of strips, powders, and wires with small thicknesses or diameters, which can be coated onto the surface of aluminum alloy drill pipes using various spraying techniques to form an aluminum-based amorphous alloy coating. This coating, without compromising the original mechanical properties of the aluminum alloy drill pipe, can fully utilize the excellent properties of the aluminum-based amorphous alloy, thus improving the hardness, wear resistance, and corrosion resistance of the aluminum alloy drill pipe. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of aluminum alloy drill pipes. This method utilizes low-temperature supersonic flame spraying technology to coat the aluminum-based amorphous alloy onto the surface of the drill pipe in the form of powder particles, forming an aluminum-based amorphous alloy coating. Without compromising the original mechanical properties of the aluminum alloy drill pipe, this method fully leverages the advantages of aluminum-based amorphous alloys, such as high strength, high toughness, superplasticity, and excellent corrosion resistance and wear resistance, to improve the shortcomings of aluminum alloy drill pipes exposed during deep oil and gas well drilling, such as low hardness, easy wear, poor high-temperature mechanical properties, and poor salt corrosion resistance. This improves the hardness, wear resistance, and corrosion resistance of the aluminum alloy drill pipe, reduces the probability of failure modes such as scratches, wear, corrosion, and fracture during drilling, and extends the service life of the aluminum alloy drill pipe under complex working conditions.

[0006] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod involves coating aluminum-based amorphous powder onto the surface of the aluminum alloy drill rod using a low-temperature supersonic flame spraying method to form an aluminum-based amorphous coating. The process parameters for the low-temperature supersonic flame spraying are as follows:

[0007] The total flow rate of propylene and oxygen is 0.004370–0.013110 kg / s, and the oxygen-fuel ratio is 2.0–4.0.

[0008] The flow rate of cooling nitrogen is 0.003678~0.011034 kg / s.

[0009] The powder injection angle is -45° to 45°, the powder injection speed is 5 to 25 m / s, and the powder spraying distance is 120 to 160 mm.

[0010] The method described in this invention uses a low-temperature supersonic flame spraying device to apply a coating, wherein the combustion-supporting gas is propylene, the combustion-supporting gas is oxygen, and the cooling gas is nitrogen.

[0011] The low-temperature supersonic flame spraying device used in this invention can be obtained by the methods disclosed in JP2009-523648 or JP2006-277286.

[0012] The aluminum-based amorphous alloy coating of the present invention is entirely composed of amorphous materials.

[0013] The coating prepared on the surface of the aluminum alloy drill rod according to the present invention is Al 86 Ni 6.75 Co 2.25 Y 3.25 La 1.75 Aluminum-based amorphous coating, this Al 86 Ni 6.75 Co 2.25 Y 3.25 La 1.75 The aluminum-based amorphous coating is a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating.

[0014] The aluminum-based amorphous powder of this invention is Al 86 Ni 6.75 Co 2.25 Y 3.25 La 1.75 The size is 5-60 μm.

[0015] The thickness of the aluminum-based amorphous coating on the surface of the aluminum alloy drill rod of the present invention is 400-500 μm.

[0016] The aluminum-based amorphous coating on the surface of the aluminum alloy drill pipe of the present invention has a surface hardness of 500-600 HV, a porosity of ≤0.30%, and a corrosion current density of ≤0.50 μA / cm². 2 .

[0017] Preferably, before spraying, the oxide film on the surface of the aluminum alloy drill rod is sanded off with sandpaper, and the aluminum alloy drill rod is immersed in a 15% sodium hydroxide solution at room temperature for 3-5 minutes. Then, the aluminum alloy drill rod is rinsed with deionized water and allowed to air dry naturally.

[0018] The low-temperature supersonic flame spraying technology described in this invention is a thermal spraying process. This invention combines the characteristics of cold spraying and high-velocity supersonic flame spraying (HVAF), giving low-temperature supersonic flame spraying the excellent performance of both low temperature and high speed, filling the technological gap between the two. Compared with other thermal spraying technologies, the low-temperature supersonic flame spraying technology of this invention can reduce the impact of thermal degradation on the sprayed material, improve the adhesion between the coating and the aluminum alloy drill rod, and reduce the number of porosity defects on the surface coating of the aluminum alloy drill rod. This plays a key role in improving the wear resistance and corrosion resistance of the aluminum alloy drill rod. This is an effective way to avoid failure modes of aluminum alloy drill rods during drilling and also a method to extend the service life of aluminum alloy drill rods.

[0019] The beneficial effects of this invention are as follows: This invention is practical and rationally designed; it utilizes low-temperature supersonic flame spraying technology to coat aluminum-based amorphous alloy in the form of powder particles onto the surface of aluminum alloy drill pipes, forming an aluminum-based amorphous alloy coating. Without compromising the original mechanical properties of the aluminum alloy drill pipe, it fully leverages the advantages of aluminum-based amorphous alloy, such as high strength, high toughness, superplasticity, and excellent corrosion resistance and wear resistance. This improves upon the shortcomings of aluminum alloy drill pipes exposed during deep oil and gas well drilling, such as low hardness, easy wear, poor high-temperature mechanical properties, and poor salt corrosion resistance. Consequently, it enhances the hardness, wear resistance, and corrosion resistance of the aluminum alloy drill pipe, reducing the probability of failure modes such as scratches, wear, corrosion, and fracture during drilling, and extending the service life of the aluminum alloy drill pipe under complex working conditions.

[0020] The low-temperature supersonic flame spraying technology employed in this invention is simple to operate, highly efficient, and has broad application prospects. It combines the advantages of cold spraying with the characteristics of high-velocity supersonic flame spraying (HVAF), exhibiting excellent low-temperature and high-speed performance. This reduces the impact of thermal degradation on the sprayed material, improves the adhesion between the coating and the substrate, and results in a coating with good deposition properties and high production efficiency. The obtained coating material is an aluminum-based amorphous alloy, which possesses a series of advantages such as high strength, high toughness, superplasticity, and excellent corrosion resistance and wear resistance. Compared to the film layer prepared on the surface of aluminum alloy drill pipes using micro-arc oxidation technology, the aluminum-based amorphous coating prepared on the surface of aluminum alloy drill pipes using the low-temperature supersonic flame spraying technology of this invention is a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating, exhibiting excellent wear resistance and corrosion resistance. The coating has a high amorphous content and few pore defects, resulting in good coating density and high bonding strength with the aluminum alloy drill rod. Facing high temperature, high friction, and salt corrosion working environments, the coating is not easy to peel off or wear through, thereby improving the hardness, wear resistance, and corrosion resistance of the aluminum alloy drill rod. This reduces the probability of failure modes such as scratches, wear, corrosion, and fracture during drilling, and extends the service life of the aluminum alloy drill rod under complex working conditions. Attached Figure Description

[0021] Figure 1 This is the XRD pattern of the aluminum-based amorphous coating prepared on the surface of an aluminum alloy drill rod in Example 1;

[0022] Figure 2 These are SEM images of the surface and cross-section of the aluminum-based amorphous coating prepared on the surface of an aluminum alloy drill rod in Example 1; wherein: (a) surface; (b) cross-section;

[0023] Figure 3 This is a corrosion current density diagram of the aluminum-based amorphous coating prepared on the surface of an aluminum alloy drill rod in Example 1. Detailed Implementation

[0024] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0025] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0026] Example 1

[0027] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod, wherein:

[0028] Before spraying, the oxide film on the surface of the aluminum alloy drill rod was sanded off with sandpaper. The drill rod was then immersed in a 15% sodium hydroxide solution at room temperature for 5 minutes to further remove oxides and oil stains. It was then rinsed with deionized water to remove any residual alkaline solution. After air-drying, the drill rod was sandblasted to facilitate adhesion between the coating and the drill rod. The low-temperature supersonic flame spraying process parameters were as follows: the total flow rate of propylene and oxygen was 0.008740 kg / s, the oxygen-fuel ratio was 2.7, the flow rate of cooling nitrogen was 0.007356 kg / s, the size of the aluminum-based amorphous powder was 5–35 μm, the powder injection angle was 0°, the powder injection speed was 10 m / s, and the powder spraying distance was 142 mm. Based on these parameters, the thickness of the prepared aluminum-based amorphous coating was 500 μm, and the calculated surface hardness was 600 HV. Figure 1 This indicates that the aluminum-based amorphous coating prepared on the surface of the aluminum alloy drill pipe is a fully amorphous alloy coating, which has fully amorphous characteristics. Figure 2 The images show (a) and (b) SEM images of the surface and cross-section of the aluminum-based amorphous coating prepared on the surface of the aluminum alloy drill pipe. Figure 2 (a) indicates that the surface melting state of the coating is good, with no unmelted particles and over-melting; Figure 2(b) indicates that the coating structure is uniform, without obvious pore defects, and has good bonding with the substrate. Based on this, the porosity of the coating is calculated to be 0.12%. Figure 3 The image shows the corrosion current density of an aluminum-based amorphous coating prepared on the surface of an aluminum alloy drill pipe. Based on this, the corrosion current density of the coating is calculated to be 0.15 μA / cm². 2 .

[0029] Example 2

[0030] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod, wherein:

[0031] Before spraying, the oxide film on the surface of the aluminum alloy drill rod is sanded off with sandpaper. The drill rod is then immersed in a 15% sodium hydroxide solution at room temperature for 5 minutes to further remove oxides and oil stains. It is then rinsed with deionized water to remove any residual alkaline solution. After air-drying, the drill rod is sandblasted to improve the adhesion between the coating and the drill rod. The low-temperature supersonic flame spraying process parameters are as follows: the total flow rate of propylene and oxygen is 0.008740 kg / s, the oxygen-fuel ratio is 3.0, the flow rate of cooling nitrogen is 0.003678 kg / s, the size of the aluminum-based amorphous powder is 5–35 μm, the powder injection angle is -45°, the powder injection speed is 5 m / s, and the powder spraying distance is 160 mm. The prepared aluminum-based amorphous coating has a thickness of 500 μm, a calculated surface hardness of 600 HV, a porosity of 0.17%, and a corrosion current density of 0.23 μA / cm². 2 .

[0032] Example 3

[0033] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod, wherein:

[0034] Before spraying, the oxide film on the surface of the aluminum alloy drill rod is sanded off with sandpaper. The drill rod is then immersed in a 15% sodium hydroxide solution at room temperature for 5 minutes to further remove oxides and oil stains. It is then rinsed with deionized water to remove any residual alkaline solution. After air-drying, the drill rod is sandblasted to improve the adhesion between the coating and the drill rod. The low-temperature supersonic flame spraying process parameters are as follows: the total flow rate of propylene and oxygen is 0.013110 kg / s, the oxygen-fuel ratio is 2.0, the flow rate of cooling nitrogen is 0.007356 kg / s, the size of the aluminum-based amorphous powder is 5–35 μm, the powder injection angle is 45°, the powder injection speed is 25 m / s, and the powder spraying distance is 120 mm. The prepared aluminum-based amorphous coating has a thickness of 500 μm, a calculated surface hardness of 550 HV, a porosity of 0.21%, and a corrosion current density of 0.31 μA / cm². 2 .

[0035] Example 4

[0036] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod, wherein:

[0037] Before spraying, the oxide film on the surface of the aluminum alloy drill rod is sanded off with sandpaper. The drill rod is then immersed in a 15% sodium hydroxide solution at room temperature for 5 minutes to further remove oxides and oil stains. It is then rinsed with deionized water to remove any residual alkaline solution. After air-drying, the drill rod is sandblasted to facilitate adhesion between the coating and the drill rod. The low-temperature supersonic flame spraying process parameters are as follows: the total flow rate of propylene and oxygen is 0.013110 kg / s, the oxygen-fuel ratio is 4.0, the flow rate of cooling nitrogen is 0.011034 kg / s, the size of the aluminum-based amorphous powder is 5–35 μm, the powder injection angle is 0°, the powder injection speed is 20 m / s, and the powder spraying distance is 160 mm. The prepared aluminum-based amorphous coating has a thickness of 400 μm, a calculated surface hardness of 500 HV, a porosity of 0.26%, and a corrosion current density of 0.37 μA / cm². 2 .

[0038] Example 5

[0039] A method for preparing a highly wear-resistant and corrosion-resistant aluminum-based amorphous coating on the surface of an aluminum alloy drill rod, wherein:

[0040] Before spraying, the oxide film on the surface of the aluminum alloy drill rod is sanded off with sandpaper. The drill rod is then immersed in a 15% sodium hydroxide solution at room temperature for 5 minutes to further remove oxides and oil stains. It is then rinsed with deionized water to remove any residual alkaline solution. After air-drying, the drill rod is sandblasted to improve the adhesion between the coating and the drill rod. The low-temperature supersonic flame spraying process parameters are as follows: the total flow rate of propylene and oxygen is 0.004370 kg / s, the oxygen-fuel ratio is 3.5, the flow rate of cooling nitrogen is 0.003678 kg / s, the size of the aluminum-based amorphous powder is 5–35 μm, the powder injection angle is 45°, the powder injection speed is 25 m / s, and the powder spraying distance is 120 mm. The prepared aluminum-based amorphous coating has a thickness of 400 μm, a calculated surface hardness of 500 HV, a porosity of 0.30%, and a corrosion current density of 0.43 μA / cm². 2 .

[0041] Comparative Example 1

[0042] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 1.5, the flow rate of cooling nitrogen was 0.003417 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 30 m / s, the powder spraying distance was 110 mm, and the coating thickness was 300 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 400 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 2.87%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 1.79 μA / cm². 2 It is higher than that of Example 1.

[0043] Comparative Example 2

[0044] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.014385 kg / s, the oxygen-fuel ratio was 4.5, the flow rate of cooling nitrogen was 0.012439 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was 60°, the powder injection speed was 3 m / s, the powder spraying distance was 110 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 400 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 3.07%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 2.87 μA / cm². 2 It is higher than that of Example 1.

[0045] Comparative Example 3

[0046] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 4.5, the flow rate of cooling nitrogen was 0.003417 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 3 m / s, the powder spraying distance was 170 mm, and the coating thickness was 300 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 450 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 2.65%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 3.17 μA / cm². 2 It is higher than that of Example 1.

[0047] Comparative Example 4

[0048] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.014385 kg / s, the oxygen-fuel ratio was 1.5, the flow rate of cooling nitrogen was 0.003417 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was 60°, the powder injection speed was 30 m / s, the powder spraying distance was 170 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 430 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 3.19%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 2.59 μA / cm². 2 It is higher than that of Example 1.

[0049] Comparative Example 5

[0050] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 4.5, the flow rate of cooling nitrogen was 0.012439 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 3 m / s, the powder spraying distance was 110 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 400 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 3.27%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 2.84 μA / cm². 2 It is higher than that of Example 1.

[0051] Comparative Example 6

[0052] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 1.5, the flow rate of cooling nitrogen was 0.012439 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was 60°, the powder injection speed was 30 m / s, the powder spraying distance was 110 mm, and the coating thickness was 300 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 450 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 3.34%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 4.06 μA / cm². 2 It is higher than that of Example 1.

[0053] Comparative Example 7

[0054] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.014385 kg / s, the oxygen-fuel ratio was 1.5, the flow rate of cooling nitrogen was 0.012439 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 30 m / s, the powder spraying distance was 170 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 470 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 4.09%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 3.35 μA / cm². 2 It is higher than that of Example 1.

[0055] Comparative Example 8

[0056] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 1.5, the flow rate of cooling nitrogen was 0.012439 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 3 m / s, the powder spraying distance was 170 mm, and the coating thickness was 300 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 460 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 4.28%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 2.18 μA / cm². 2 It is higher than that of Example 1.

[0057] Comparative Example 9

[0058] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.014385 kg / s, the oxygen-fuel ratio was 4.5, the flow rate of cooling nitrogen was 0.003417 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was -60°, the powder injection speed was 30 m / s, the powder spraying distance was 170 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 480 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 5.17%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 2.92 μA / cm². 2 It is higher than that of Example 1.

[0059] Comparative Example 10

[0060] The differences from Example 1 are as follows: the total flow rate of propylene and oxygen was 0.003581 kg / s, the oxygen-fuel ratio was 4.5, the flow rate of cooling nitrogen was 0.003417 kg / s, the size of the aluminum-based amorphous powder was 5–60 μm, the powder injection angle was 60°, the powder injection speed was 30 m / s, the powder spraying distance was 110 mm, and the coating thickness was 600 μm. Results: The surface hardness of the prepared aluminum-based amorphous coating was 430 HV, lower than that of Example 1; the porosity of the prepared aluminum-based amorphous coating was 5.37%, higher than that of Example 1; and the corrosion current density of the prepared aluminum-based amorphous coating was 3.61 μA / cm². 2 It is higher than that of Example 1.

Claims

1. A method of surface preparation of an aluminum alloy drill pipe with high wear and corrosion resistant aluminum-based amorphous coating, characterized by: Aluminum-based amorphous powder is coated onto the surface of an aluminum alloy drill pipe using a low-temperature supersonic flame spraying method to form an aluminum-based amorphous coating. The aluminum-based amorphous alloy in the coating is entirely composed of amorphous materials. The process parameters for the low-temperature supersonic flame spraying are as follows: The total flow rate of propylene and oxygen is 0.004370~0.013110 kg / s, and the oxygen-fuel ratio is 2.0~4.

0. The flow rate of cooling nitrogen is 0.003678~0.011034 kg / s. The powder injection angle is -45° to 45°, the powder injection speed is 5 to 25 m / s, and the powder spraying distance is 120 to 160 mm. The aluminum-based amorphous powder is Al 86 Ni 6.75 Co 2.25 Y 3.25 La 1.75 , and the size is 5-60 μm.

2. The method of claim 1, wherein: The thickness of the aluminum-based amorphous coating on the surface of the aluminum alloy drill pipe is 400~500μm.

3. The method of claim 1, wherein: The surface hardness of the aluminum alloy drill rod surface aluminum-based amorphous coating is 500-600 HV, the porosity of the coating is ≤0.30%, and the corrosion current density of the coating is ≤0.50 μA / cm 2 .

4. The method of claim 1, wherein: Before spraying, use sandpaper to remove the oxide film on the surface of the aluminum alloy drill rod. Immerse the aluminum alloy drill rod in a 15% sodium hydroxide solution at room temperature for 3-5 minutes, then rinse the aluminum alloy drill rod with deionized water and let it air dry naturally.

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