Cold spraying device and preparation method of amorphous alloy coating

Abstract

The invention provides a cold spraying device and a preparation method of an amorphous alloy coating. The cold spraying device comprises a Laval nozzle and a temperature compensation unit. The temperature compensation unit is used for heating the amorphous alloy powder between the expansion section and the matrix to realize temperature compensation; according to the preparation method of the amorphous alloy coating, in the deposition process, the amorphous alloy powder between the expansion section and the base body is heated through the temperature compensation unit so as to achieve temperature compensation, generation of a nanophase in the amorphous alloy powder is promoted, and the mechanical property and the like are improved; compared with a thermal spraying technology, a laser cladding technology or a laser-assisted technology, crystallization of the amorphous alloy can be avoided, and the excellent performance of the amorphous alloy can be kept in the coating; compared with a pure cold spraying technology, uniform deformation of the amorphous alloy powder can be achieved, the density of the amorphous alloy coating is improved, and therefore the advantages of the amorphous alloy coating in the fields of corrosion prevention, abrasion resistance and the like are fully played.

Description

Technical Field

[0001] The invention relates to the technical field of cold spraying, and in particular to a cold spraying device and a method for preparing an amorphous alloy coating. Background Art

[0002] Amorphous alloys are in a state where atoms in the internal structure present a long-range disordered arrangement. Therefore, compared with traditional crystalline materials, they have better mechanical properties and resistance to corrosion from a variety of media. Currently, amorphous alloys are widely used in many fields such as corrosion protection, wear resistance, and motor manufacturing and processing, especially in surface protection. They have broad application prospects. At present, thermal spraying technology (such as plasma spraying, arc spraying, etc.) is often used to prepare amorphous alloy coatings on the surface of the workpiece to be protected. However, thermal spraying requires heating the amorphous alloy powder to a molten or semi-molten state before deposition to form a coating, which results in a certain intermediate phase in the prepared amorphous alloy coating, resulting in a decrease or deterioration of the corresponding performance. In order to avoid this problem, cold spraying technology is gradually being used to prepare amorphous alloy coatings.

[0003] Cold spraying technology is a new coating preparation process that has developed rapidly in recent years. Under the action of high-pressure gas (helium, nitrogen, compressed air or a mixture of them), powder particles are accelerated by a Laval spray gun and hit the substrate at a very high speed, resulting in severe plastic deformation and deposition to form a coating. The coating prepared by cold spraying can avoid crystallization, oxidation and phase change of the powder, and its bonding strength is high (generally greater than 40MPa), so the coating is not easy to peel off. In addition, cold spraying equipment has low cost, simple operation, and no pollution to the environment during the spraying process. It is a new green and environmentally friendly surface strengthening technology. At present, Fe-based, Al-based (such as Al-TM-Re series) and Ni-based amorphous alloy coatings have been prepared.

[0004] However, there are great differences in the amorphous forming ability of different types of amorphous alloys, which are mainly reflected in the following aspects: (1) Fe-based and Zr-based amorphous alloys have a wide supercooled liquid phase region (about 50-90°C) and strong amorphous forming ability; (2) Although Al-based amorphous alloys can improve their amorphous forming ability by adding other alloying elements (such as transition elements and rare metal elements), they still have the problem of narrow supercooled liquid phase region (about 20°C) and poor amorphous forming ability. Since amorphous alloys have good mechanical properties in the supercooled liquid phase region, the particle temperature needs to be controlled within this range during the spraying process. In the actual cold spraying process, due to the acceleration of the Laval spray gun, the temperature of the amorphous alloy particles reaches the highest at the throat, and then the temperature gradually decreases. This means that for aluminum-based amorphous alloys with poor amorphous forming ability, the temperature at the moment of particle collision is lower than the supercooled liquid phase region, resulting in non-uniform deformation of the particles, thereby generating more pores, which is not conducive to the performance of corrosion resistance and wear resistance. For amorphous alloys with strong amorphous forming ability, if the temperature of the supercooled liquid phase is too high (such as the glass transition temperature > 550°C), the preheating temperature needs to be further increased to the upper limit of the equipment or even exceed the upper limit of the preheating temperature in order for the amorphous alloy particles to reach the supercooled liquid phase and deposit to form a dense coating.

[0005] Based on the defects of the current cold spraying method for preparing amorphous alloy coatings, it is necessary to improve it. Summary of the invention

[0006] In view of this, the present invention provides a cold spraying device and a method for preparing an amorphous alloy coating to solve or at least partially solve the defects existing in the prior art.

[0007] In a first aspect, the present invention provides a cold spraying device, comprising:

[0008] a Rafale nozzle having a diverging section;

[0009] A temperature compensation unit, which is located outside the expansion section and is used to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation;

[0010] Wherein, the temperature compensation unit is an induction heating coil sleeved outside the expansion section;

[0011] Or, the temperature compensation unit is a heating spray gun located outside the expansion section and reciprocating along the axis of the Rafale nozzle;

[0012] Alternatively, the temperature compensation unit is a laser beam located outside the expansion section nozzle outlet and can reciprocate along the Rafale nozzle axis between the expansion section outlet and the substrate, and the laser beam forms a certain angle with the Rafale nozzle axis.

[0013] Preferably, if the temperature compensation unit is an induction heating coil, a cooling unit is also provided on the periphery of the expansion section;

[0014] The number of turns of the induction heating coil is 1 to 5000, and the inner diameter is 10 to 500 mm.

[0015] Preferably, the heating spray gun is a plasma spray gun or an oxyacetylene flame spray gun;

[0016] If the heating spray gun is a plasma spray gun, the distance between the plasma spray gun and the expansion section is 50 to 1000 mm, and the nozzle diameter of the plasma spray gun is 2 to 50 mm;

[0017] If the heating spray gun is an oxyacetylene flame spray gun, the distance between the oxyacetylene flame spray gun and the expansion section is 50 to 500 mm;

[0018] If the temperature compensation unit is a laser beam, the angle between the laser beam and the axis of the Lafayette nozzle is 20-90°.

[0019] In a second aspect, the present invention further provides a method for preparing an amorphous alloy coating, which is prepared using the cold spraying device, comprising the following steps:

[0020] The amorphous alloy powder is sprayed out through the Rafale nozzle and deposited on the substrate to form an amorphous alloy coating on the deposition surface of the substrate;

[0021] During the deposition process, the temperature compensation unit is started to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation.

[0022] Preferably, the temperature compensation unit is an induction heating coil. During the deposition process, the current of the induction heating coil is controlled to be 0.1-200A and the voltage is controlled to be 5-380V.

[0023] Preferably, the temperature compensation unit is a heating spray gun, and the heating spray gun is a plasma spray gun. During the deposition process, the power of the plasma spray gun is controlled to be 1 to 80 kW, the flow rate is 10 to 1500 mL / s, and the moving speed is 10 to 500 mm / s;

[0024] Alternatively, the temperature compensation unit is a heating spray gun, and the heating spray gun is an oxyacetylene flame spray gun. During the deposition process, the air consumption and pressure ratio of the oxyacetylene flame spray gun are controlled to be 0.1-10, the nozzle diameter and spray width ratio of the oxyacetylene flame spray gun are controlled to be 0.1-15, and the moving rate is 10-500 mm / s.

[0025] Preferably, the temperature compensation unit is a laser beam, which is generated by a laser. During deposition, the laser power is controlled to be 100 to 8000 W, and the moving speed of the laser beam is 10 to 500 mm / s.

[0026] Preferably, the process parameters controlled during cold spraying are: the spraying carrier gas is nitrogen or helium or compressed air, the spraying pressure is 2-5.5 MPa, the carrier gas preheating temperature is 250-400°C, the spraying distance is 20-50 mm, the gun moving speed is 10-500 mm / s, and the powder feeding amount is 5-100 g / min.

[0027] Preferably, during the deposition process, the cooling unit is started to control the cooling temperature to be 5-25°C.

[0028] Preferably, the particle size of the amorphous alloy powder is 15 to 30 μm;

[0029] The matrix includes any one of a metal matrix and its alloy matrix, an amorphous alloy matrix, a ceramic matrix, and a polymer material matrix;

[0030] A cooling device is provided on the side of the substrate away from the deposition surface. During deposition, the cooling device is started to cool the substrate, and the temperature of the substrate is controlled to be 10-50°C.

[0031] The cold spraying device and the method for preparing the amorphous alloy coating of the present invention have the following beneficial effects compared with the prior art:

[0032] 1. The cold spraying device of the present invention comprises a Laval nozzle and a temperature compensation unit; the temperature compensation unit is used to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation; by setting the temperature compensation unit, the present invention can perform appropriate temperature compensation in the expansion section of the Laval nozzle and the two end areas from the outlet to the substrate, so that the temperature of the amorphous alloy is within the supercooled liquid phase region at the moment of collision, and uniform deformation occurs to obtain a dense cold sprayed amorphous alloy coating.

[0033] 2. The preparation method of the amorphous alloy coating of the present invention utilizes a temperature compensation unit to heat the amorphous alloy powder between the expansion section and the substrate during the deposition process to achieve temperature compensation, thereby promoting the generation of nanophases inside the amorphous alloy powder to improve mechanical properties, corrosion resistance and wear resistance, etc.; compared with thermal spraying technology, laser cladding or laser-assisted technology, the crystallization of the amorphous alloy can be avoided, so that its excellent performance is maintained in the coating; compared with simple cold spraying technology, the present invention can achieve uniform deformation of the amorphous alloy powder and improve the density of the amorphous alloy coating, thereby giving full play to the advantages of the amorphous alloy coating in the fields of corrosion protection and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 It is a structural schematic diagram of a cold spraying device in one embodiment of the present invention;

[0036] Figure 2 It is a structural schematic diagram of a cold spraying device in another embodiment of the present invention;

[0037] Figure 3 It is a structural schematic diagram of a cold spraying device in another embodiment of the present invention;

[0038] Figure 4 is a SEM image of the aluminum-based amorphous alloy coating prepared on the AZ31B substrate in Example 1;

[0039] Figure 5 This is a physical picture of the aluminum-based amorphous alloy coating prepared on the Al7075 substrate in Example 2.

[0040] Figure 6 is a SEM image of the aluminum-based amorphous alloy coating prepared on the AZ31B substrate in Comparative Example 1; DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] The following are described in detail. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) within the indicated range.

[0044] The present invention provides a cold spraying device, such as Figures 1 to 3 As shown, including:

[0045] A Rafale nozzle 1 having a diverging section 11;

[0046] A temperature compensation unit, which is located outside the expansion section 11 and is used to heat the amorphous alloy powder between the expansion section 11 and the substrate to achieve temperature compensation;

[0047] Wherein, the temperature compensation unit is an induction heating coil 2 sleeved outside the expansion section;

[0048] Or, the temperature compensation unit is a heating spray gun 3 located outside the expansion section 11 and reciprocating along the axis of the Rafale nozzle;

[0049] Alternatively, the temperature compensation unit is a laser beam 7 located outside the expansion section nozzle outlet and capable of reciprocating along the Rafale nozzle axis between the expansion section outlet and the substrate, and the laser beam 7 forms a certain angle with the Rafale nozzle axis.

[0050] The cold spraying device of the present invention comprises a Rafale nozzle 1 and a temperature compensation unit. The Rafale nozzle 1 comprises a connected contraction section 13, a throat 12 and an expansion section 11, and a temperature compensation unit is arranged outside the expansion section 11; specifically, the temperature compensation unit is an induction heating coil 2 sleeved outside the expansion section, or the temperature compensation unit is a heating spray gun 3 located outside the expansion section 11 and movable along the axis of the Rafale nozzle; or the temperature compensation unit is a laser beam 7, and the laser beam 7 is located outside the nozzle outlet of the expansion section and can reciprocate along the axis of the Rafale nozzle between the outlet of the expansion section and the substrate, and the laser beam 7 forms a certain angle with the axis of the Rafale nozzle. During cold spraying, the heated gas is accelerated after expansion through the contraction section 13 and the throat 12 of the Laval nozzle 1 to form a high-speed airflow that enters the expansion section 11. At the same time, the heated gas accelerates and preheats the amorphous alloy powder 6 in the Laval nozzle. The amorphous alloy powder is ejected from the expansion section 11 of the Laval nozzle 1 along with the high-speed airflow and deposited on the substrate 5 to form an amorphous alloy coating. Based on the characteristic that the temperature of the cold-sprayed amorphous alloy powder decreases at the expansion section and outlet of the Laval nozzle, a temperature compensation unit is provided in the expansion section and outlet area of ​​the Laval nozzle. For amorphous alloy materials with too high a temperature in the supercooled liquid phase region, the temperature compensation area can be extended to the contraction section of the Laval nozzle. By providing a temperature compensation unit, the present invention can perform appropriate temperature compensation in the expansion section of the Laval nozzle and in the two end areas from the outlet to the substrate, so that the temperature of the amorphous alloy is within the supercooled liquid phase region at the moment of collision, and uniform deformation occurs, thereby obtaining a dense cold-sprayed amorphous alloy coating.

[0051] In some embodiments, if the temperature compensation unit is an induction heating coil, a cooling unit 4 is also provided on the periphery of the expansion section;

[0052] The number of turns of the induction heating coil is 1 to 5000, and the inner diameter is 10 to 500 mm.

[0053] Specifically, Figure 1 The induction heating coil used directly heats the amorphous alloy powder to achieve temperature compensation; this method has a good electromagnetic induction effect on Fe-based amorphous alloys, so it can achieve a rapid temperature increase; for Al-based amorphous alloys, the electromagnetic induction effect is relatively weak, but because the temperature difference that needs to be compensated is generally smaller than that of Fe-based amorphous alloys, this method is also used; the Rafale nozzle materials that need to be used with the induction heating coil include metals, ceramics, polymer materials, etc., because induction heating does not generate eddy currents inside, so the spray gun can be avoided from being blocked; using this method for temperature compensation, a cooling unit can be installed on the outer peripheral surface of the expansion section 11 of the Rafale nozzle to avoid clogging of the Rafale nozzle; the inner diameter of the induction heating coil can be fixed or variable.

[0054] In some embodiments, the heating spray gun is a flame spray gun, and the flame spray gun is a plasma spray gun or an oxyacetylene flame spray gun; the heating spray gun is located on one side or both sides of the contraction section.

[0055] The flame spray gun is used to heat the airflow inside the expansion section, and then the temperature of the amorphous alloy powder inside the expansion section is compensated by heat conduction. This method has high requirements on the temperature resistance of the Rafale nozzle material, and Rafale nozzles made of ceramic, metal ceramic or high-temperature alloy materials are generally selected; when this method is used for temperature compensation, there is no need to install a cooling device in the expansion section.

[0056] In some embodiments, when performing temperature compensation, the temperature compensation device needs to be fixed, wherein: for the method of using an induction heating coil, the heating coil is wound around the surface of the expansion section 11 of the Rafale nozzle and then insulated with a heat-insulating material; for the method of using a flame spray gun, a robotic arm or a corresponding two-dimensional / three-dimensional work platform can be used to fix it on one side or both sides of the Rafale nozzle, and the flame spray gun can move back and forth along the expansion section at a moving rate of 10 to 500 mm / s.

[0057] In some embodiments, if the heating spray gun is a plasma spray gun, the distance between the plasma spray gun and the expansion section is 50-1000 mm, and the nozzle diameter of the plasma spray gun is 2-50 mm.

[0058] In some embodiments, if the heating spray gun is an oxyacetylene flame spray gun, the distance between the oxyacetylene flame spray gun and the expansion section is 50-500 mm.

[0059] In some embodiments, if the temperature compensation unit is a laser beam, the angle between the laser beam and the axis of the Rafale nozzle is 20-90°, and the laser beam reciprocates between the outlet of the expansion section 11 and the surface of the substrate.

[0060] Based on the same inventive concept, the present invention also provides a method for preparing an amorphous alloy coating, which is prepared by using the above-mentioned cold spraying device, and comprises the following steps:

[0061] The amorphous alloy powder is sprayed out through the Rafale nozzle and deposited on the substrate to form an amorphous alloy coating on the deposition surface of the substrate;

[0062] During the deposition process, the temperature compensation unit is started to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation.

[0063] The preparation method of the amorphous alloy coating of the present invention sets the parameters such as pressure, temperature, spraying distance, and gun moving speed required for spraying based on the cold spraying device used and the temperature range of the supercooled liquid phase region of the amorphous alloy powder used; selects the temperature difference between the amorphous alloy particles at the throat of the spray gun and the moment of collision obtained by numerical simulation. Figure 1 or Figure 2 A temperature compensation method is used, and the deposition of amorphous alloy particles in the supercooled liquid phase is achieved by adjusting the process parameters of the selected temperature compensation method. Among them, for the temperature compensation method of the induction heating coil, the main adjusted process parameters are the current, voltage and number of turns of the induction heating coil; for the temperature compensation method of the heating spray gun, the main adjusted process parameter is the power of the flame spray gun.

[0064] In some embodiments, the temperature compensation unit is an induction heating coil. During the deposition process, the current of the induction heating coil is controlled to be 0.1-200A and the voltage is controlled to be 5-380V.

[0065] In some embodiments, the temperature compensation unit is a heating spray gun, which is a plasma spray gun. During the deposition process, the plasma spray gun is controlled to have a power of 1 to 80 kW, a flow rate of 10 to 1500 mL / s, and a moving speed of 10 to 500 mm / s.

[0066] In some embodiments, the temperature compensation unit is a heating spray gun, which is an oxyacetylene flame spray gun. During the deposition process, the air consumption and pressure ratio of the oxyacetylene flame spray gun are controlled to be 0.1 to 10, the nozzle diameter and spray width ratio of the oxyacetylene flame spray gun are controlled to be 0.1 to 15, and the moving rate is 10 to 500 mm / s.

[0067] In some embodiments, the temperature compensation unit is a laser beam, which is generated by a laser. During deposition, the laser power is controlled to be 100 to 8000 W, and the moving speed of the laser beam is 10 to 500 mm / s.

[0068] In some embodiments, the process parameters controlled during cold spraying are: the process parameters controlled during cold spraying are: the spraying carrier gas is nitrogen or helium or compressed air, the spraying pressure is 2-5.5Mpa, the carrier gas preheating temperature is 250-400°C, the spraying distance is 20-50mm, the gun moving speed is 10-500mm / s, and the powder feeding amount is 5-100g / min.

[0069] In some embodiments, if the temperature compensation unit is an induction heating coil, during the deposition process, the cooling unit is started to control the cooling temperature to 5-25°C; specifically, the cooling unit is a chiller, and the chiller power is controlled to 1-20KW, so that the temperature of the cooling water is 5-25°C to meet the heat dissipation requirements of the inside of the Rafale nozzle under the temperature compensation of the induction coil.

[0070] In some embodiments, spherical amorphous alloy powder prepared by gas atomization is used as spray powder, and the particle size of the amorphous alloy powder is 15-30 μm.

[0071] In some embodiments, the amorphous alloy powder is an aluminum-based amorphous alloy powder, specifically an Al-Tm-Re series aluminum-based amorphous alloy powder. In the Al-TM-RE series amorphous alloy, the Al element content is greater than 80wt.%, TM is Fe, Co, Ni or Cu, and RE is a rare earth element.

[0072] In some embodiments, the substrate includes any one of a metal and its alloy substrate, an amorphous alloy substrate, a ceramic substrate, and a polymer material substrate. For example, the substrate is an AZ31B substrate, i.e., an AZ31B magnesium alloy substrate; the substrate may also be an Al7075 substrate, i.e., a 7075 aluminum plate substrate.

[0073] In some embodiments, a cooling device is provided on the side of the substrate away from the deposition surface, and the cooling device is started during deposition to cool the substrate, and the substrate temperature is controlled to be 10-50° C. Specifically, the substrate during the spraying process needs to be properly cooled to avoid heat accumulation, wherein: for metal substrates, it is easily affected by the heating of the induction coil, and a water cooling device needs to be added to the back of the substrate; for polymer substrates, it is easily affected by the flame spray gun to cause heat accumulation, and a water cooling device needs to be added to the back of the substrate.

[0074] In some embodiments, before deposition, the surface of the sprayed substrate is treated, such as sandblasting, shot blasting, sandpaper polishing, ultrasonic cleaning or degreasing.

[0075] The above method can be used not only to prepare high-density amorphous alloy coatings, but also to prepare amorphous alloy bulk materials. The cold spraying device suitable for the present invention is not limited to a high-pressure cold spraying device, but also suitable for a low-pressure cold spraying device; the materials used in the present invention include not only amorphous alloys, but also metal materials that need to be deformed at a higher temperature, such as Ni-based high-temperature alloys.

[0076] The following further illustrates the preparation method of the amorphous alloy coating of the present application with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0077] Example 1

[0078] The present invention provides a method for preparing an amorphous alloy coating. Figure 1 The cold spraying device shown is prepared, comprising the following steps:

[0079] The amorphous alloy powder is sprayed out through a Rafale nozzle and deposited on an AZ31B substrate to form an amorphous alloy coating with an average thickness of 400 μm on the substrate deposition surface;

[0080] Among them, during the deposition process, an induction heating coil is used for temperature compensation;

[0081] The inner diameter of the induction heating coil is 120 mm, the material of the induction coil is a copper tube, the number of turns of the induction heating coil is 55, the length of the Laval nozzle expansion section is 100 mm, the length of the induction heating coil on the axis of the Laval nozzle is 100 mm, and the current of the induction heating coil is controlled to be 15 A and the voltage is 380 V during deposition;

[0082] The process parameters controlled during cold spraying are: spray carrier gas is nitrogen, spray pressure is 4Mpa, carrier gas preheating temperature is 360℃, spray distance is 20mm, gun moving speed is 100mm / s, powder feeding amount is 15g / min;

[0083] During the deposition process, the cooling unit is started. The cooling unit is a water chiller. The power of the water chiller is controlled to be 15KW and the temperature of the cooling water is 12°C.

[0084] The amorphous alloy powder is an aluminum-based amorphous alloy powder with an average particle size of 25 μm;

[0085] The amorphous alloy powder is an Al-Tm-Re series aluminum-based amorphous alloy powder, and the amorphous alloy powder includes the following elements in mass fractions: Al 86%, Ni 7%, Co 1%, Y 5%, and La 1%;

[0086] A cooling device is provided on the side of the substrate away from the deposition surface. During deposition, the cooling device is started to cool the substrate, and the substrate temperature is controlled at 20°C.

[0087] Example 2

[0088] The present invention provides a method for preparing an amorphous alloy coating. Figure 1 The cold spraying device shown is prepared, comprising the following steps:

[0089] The amorphous alloy powder is sprayed out through a Rafale nozzle and deposited on an Al7075 substrate to form an amorphous alloy coating having a thickness greater than 4 mm on the substrate deposition surface;

[0090] Among them, during the deposition process, an induction heating coil is used for temperature compensation;

[0091] The inner diameter of the induction heating coil is 120 mm, the material of the induction coil is a copper tube, the number of turns of the induction heating coil is 55, the length of the Laval nozzle expansion section is 100 mm, the length of the induction heating coil on the axis of the Laval nozzle is 100 mm, and the current of the induction heating coil is controlled to be 18 A and the voltage is 200 V during deposition;

[0092] The process parameters controlled during cold spraying are: spray carrier gas is nitrogen, spray pressure is 4.3Mpa, carrier gas preheating temperature is 340℃, spray distance is 25mm, gun moving speed is 80mm / s, powder feeding amount is 28g / min;

[0093] During the deposition process, the cooling unit is started. The cooling unit is a water chiller. The power of the water chiller is controlled to be 15KW and the temperature of the cooling water is 12°C.

[0094] The amorphous alloy powder is an aluminum-based amorphous alloy powder with an average particle size of 25 μm; the amorphous alloy powder is an Al-Tm-Re series aluminum-based amorphous alloy powder, and the amorphous alloy powder is an Al-Tm-Re series aluminum-based amorphous alloy powder, and the amorphous alloy powder includes the following elements by mass fraction: Al 86%, Ni 7%, Co 1%, Y 5%, and La 1%;

[0095] A cooling device is provided on the side of the substrate away from the deposition surface. During deposition, the cooling device is started to cool the substrate, and the substrate temperature is controlled at 20°C.

[0096] Comparative Example 1

[0097] This comparative example provides a method for preparing an amorphous alloy coating, which is the same as that of Example 1, except that the cold spraying device does not have a temperature compensation unit, and specifically includes the following steps:

[0098] The amorphous alloy powder is sprayed out through a Rafale nozzle and deposited on an AZ31B substrate to form an amorphous alloy coating with an average thickness of 400 μm on the substrate deposition surface;

[0099] Among them, the process parameters controlled during cold spraying are: spray carrier gas is nitrogen, spray pressure is 4Mpa, carrier gas preheating temperature is 360℃, spray distance is 20mm, gun moving speed is 100mm / s, powder feeding amount is 15g / min;

[0100] The amorphous alloy powder is an aluminum-based amorphous alloy powder with an average particle size of 25 μm;

[0101] The amorphous alloy powder is an Al-Tm-Re series aluminum-based amorphous alloy powder, and the amorphous alloy powder includes the following elements in mass fractions: Al 86%, Ni 7%, Co 1%, Y 5%, and La 1%;

[0102] A cooling device is provided on the side of the substrate away from the deposition surface. During deposition, the cooling device is started to cool the substrate, and the substrate temperature is controlled at 20°C.

[0103] Figure 4 The SEM image of the aluminum-based amorphous alloy coating prepared on the AZ31B substrate in Example 1 ( Figure 4 The upper middle part is the aluminum-based amorphous alloy coating). Figure 4 It can be seen that the prepared aluminum-based amorphous alloy coating is dense inside and has a porosity of <1%.

[0104] Figure 5 This is a photo of the aluminum-based amorphous alloy coating prepared on the Al7075 substrate in Example 2. Figure 5 It can be seen that the surface of the prepared aluminum-based amorphous alloy coating is dense and has no holes.

[0105] Figure 6 The SEM image of the aluminum-based amorphous alloy coating prepared on the AZ31B substrate in Comparative Example 1 ( Figure 6 The upper middle part is the aluminum-based amorphous alloy coating). Figure 6 It can be seen that in Comparative Example 1, due to the lack of temperature compensation, the temperature of the aluminum-based amorphous alloy particles at the moment of collision is lower than the supercooled liquid phase, resulting in non-uniform deformation of the particles, thereby generating more pores, which reduces the corrosion and wear resistance of the aluminum-based amorphous alloy coating.

[0106] The aluminum-based amorphous alloy coatings prepared in Example 1 and Comparative Example 1 were respectively placed in a 3.5% mass fraction NaCl aqueous solution, and a polarization curve experiment was carried out using a three-electrode system to test the self-corrosion potential and self-corrosion current of the aluminum-based amorphous alloy coating. The results are shown in Table 1; wherein, during the test, the working electrode was the aluminum-based amorphous alloy coating, the reference electrode was a saturated calomel electrode (SCE), the counter electrode was Pt, the scanning voltage range was ±1000mV, and the scanning rate was 0.1mV / s.

[0107] Table 1 - Self-corrosion potential and self-corrosion current of aluminum-based amorphous alloy coating in Example 1 and Comparative Example 1

[0108] Example <![CDATA[Self-corrosion potential / V SCE > <![CDATA[Self - corrosion current / (10 -4 A·cm -2 )]]> Comparative Example 1 -0.867V 6.52 Example 1 -0.815V 2.98

[0109] It can be seen from Table 1 that the aluminum-based amorphous alloy coating prepared by temperature compensation in Example 1 has a higher self-corrosion potential and a lower self-corrosion current than that in Comparative Example 1, indicating that the aluminum-based amorphous alloy coating prepared by the present invention has good corrosion resistance.

[0110] The aluminum-based amorphous alloy coatings prepared in Example 1 and Comparative Example 1 were respectively subjected to wear rate tests at a load of 10 N and a wear distance of 562.5 m. The results are shown in Table 2.

[0111] Table 2 - Wear rate of aluminum-based amorphous alloy coating in Example 1 and Comparative Example 1

[0112] Example <![CDATA[Wear rate / (10 -4 mm -3 ·N -1 ·m -1 )]]> Comparative Example 1 2.74 Example 1 2.25

[0113] It can be seen from Table 2 that the aluminum-based amorphous alloy coating prepared by temperature compensation in Example 1 has a lower wear rate than that in Comparative Example 1, indicating that the aluminum-based amorphous alloy coating prepared by the present invention has good wear resistance.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cold spraying device, characterized in that: include: a Rafale nozzle having a diverging section; A temperature compensation unit, which is located outside the expansion section and is used to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation; Wherein, the temperature compensation unit is an induction heating coil sleeved outside the expansion section; Or, the temperature compensation unit is a heating spray gun located outside the expansion section and reciprocating along the axis of the Rafale nozzle; Alternatively, the temperature compensation unit is a laser beam located outside the expansion section nozzle outlet and can reciprocate along the Rafale nozzle axis between the expansion section outlet and the substrate, and the laser beam forms a certain angle with the Rafale nozzle axis.

2. The cold spraying device according to claim 1, characterized in that: If the temperature compensation unit is an induction heating coil, a cooling unit is also provided on the periphery of the expansion section; The number of turns of the induction heating coil is 1 to 5000, and the inner diameter is 10 to 500 mm.

3. The cold spraying device according to claim 1, characterized in that: The heating spray gun is a plasma spray gun or an oxyacetylene flame spray gun; If the heating spray gun is a plasma spray gun, the distance between the plasma spray gun and the expansion section is 50 to 1000 mm, and the nozzle diameter of the plasma spray gun is 2 to 50 mm; If the heating spray gun is an oxyacetylene flame spray gun, the distance between the oxyacetylene flame spray gun and the expansion section is 50 to 500 mm; If the temperature compensation unit is a laser beam, the angle between the laser beam and the axis of the Lafayette nozzle is 20-90°.

4. A method for preparing an amorphous alloy coating, using the cold spraying device as described in any one of claims 1 to 3, characterized in that: The following steps are involved: The amorphous alloy powder is sprayed out through the Rafale nozzle and deposited on the substrate to form an amorphous alloy coating on the deposition surface of the substrate; During the deposition process, the temperature compensation unit is started to heat the amorphous alloy powder between the expansion section and the substrate to achieve temperature compensation.

5. The method for preparing an amorphous alloy coating according to claim 4, characterized in that: The temperature compensation unit is an induction heating coil. During the deposition process, the current of the induction heating coil is controlled to be 0.1-200A and the voltage is controlled to be 5-380V.

6. The method for preparing an amorphous alloy coating according to claim 4, characterized in that: The temperature compensation unit is a heating spray gun, and the heating spray gun is a plasma spray gun. During the deposition process, the power of the plasma spray gun is controlled to be 1-80KW, the flow rate is 10-1500mL / s, and the moving speed is 10-500mm / s; Alternatively, the temperature compensation unit is a heating spray gun, and the heating spray gun is an oxyacetylene flame spray gun. During the deposition process, the air consumption and pressure ratio of the oxyacetylene flame spray gun are controlled to be 0.1-10, the nozzle diameter and spray width ratio of the oxyacetylene flame spray gun are controlled to be 0.1-15, and the moving rate is 10-500 mm / s.

7. The method for preparing an amorphous alloy coating according to claim 4, characterized in that: The temperature compensation unit is a laser beam, which is generated by a laser. During deposition, the laser power is controlled to be 100-8000W, and the moving speed of the laser beam is 10-500mm / s.

8. The method for preparing an amorphous alloy coating according to any one of claims 4 to 7, characterized in that: The process parameters controlled during cold spraying are: the spraying carrier gas is nitrogen, helium or compressed air, the spraying pressure is 2-5.5Mpa, the carrier gas preheating temperature is 250-400℃, the spraying distance is 20-50mm, the gun moving speed is 10-500mm / s, and the powder feeding amount is 5-100g / min.

9. The method for preparing an amorphous alloy coating according to claim 5, characterized in that: During the deposition process, the cooling unit is started and the cooling temperature is controlled to be 5-25°C.

10. The method for preparing an amorphous alloy coating according to claim 4, characterized in that: The particle size of the amorphous alloy powder is 15 to 30 μm; The matrix includes any one of a metal matrix and its alloy matrix, an amorphous alloy matrix, a ceramic matrix, and a polymer material matrix; A cooling device is provided on the side of the substrate away from the deposition surface. During deposition, the cooling device is started to cool the substrate and the substrate temperature is controlled to be 10-50°C.

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