Low-temperature thermal spraying method and low-temperature thermal spraying equipment

Abstract

The present invention provides a method and apparatus for forming a low-temperature thermal spray molded article having good mechanical properties (minimum porosity, high adhesive tensile strength, high tensile strength, and / or high elongation at fracture) and good corrosion resistance. [Solution] The present invention relates to a method and apparatus for forming a thermal spray molded body 10 on a substrate surface 30 by low-temperature injection. In the present invention, raw material particles and forging particles are introduced into a process airflow 20 to accelerate the process airflow 20. The accelerated raw material particles and forging particles are ejected toward the substrate surface 30 by the process airflow. The raw material particles have a speed at which they adhere to the substrate surface 30 and form a thermal spray molded body 10, but the forging particles do not adhere to the substrate surface 30 due to their low speed. The raw material particles and forging particles are made of the same material or materials from the same group.

Description

[Technical Field]

[0001] This invention relates to a method for forming and producing a low-temperature spray-molded body on a substrate surface, particularly to a low-temperature spraying method and a low-temperature spraying apparatus for producing a low-temperature spray-molded body on a substrate surface. The low-temperature spraying method is a technique for forming a spray-molded body on a substrate surface by impacting a powder material onto the substrate surface without melting it. [Background technology]

[0002] Cryogenic spraying (also known as "low-temperature gas spraying") is a material fixing method that uses dynamic energy to fix powdered materials to a substrate. In cryogenic spraying, the supplied material is neither melted nor fused, but the supplied material, i.e., powdered particles, is accelerated through a process airflow and sprayed at high speed onto the substrate surface to be coated, thereby fixing the powdered particles to the substrate surface. This material fixing method can fix powdered particles to the substrate surface at different layer thicknesses.

[0003] To generate a process airflow for high-speed transport of powder materials, a heated and pressurized process gas is accelerated at high speed (e.g., supersonic) by expansion within a shrinking and diffusing nozzle device while simultaneously being cooled. After the expansion of the process gas, the process airflow is maintained at a temperature range of 100°C or lower. The process gases used include nitrogen, carbon dioxide, helium, compressed air, water vapor, and argon. Similarly, mixtures of multiple such gases are also used as process gases.

[0004] The powder particles injected into the contraction region of the contraction diffusion nozzle device are accelerated by the process gas, which forms the process airflow, reaching speeds of, for example, 1500 m / s or less in conventional low-temperature thermal spraying methods. As the powder particles collide with the substrate surface in the contraction ejection flow, they deform themselves at least on the substrate surface, forming a high-density, low-porosity material adhesion layer that firmly adheres to the substrate surface along with minute oxide particles. The thickness of the material adhesion layer can be set from several hundred millimeters to several millimeters or even several centimeters.

[0005] Unlike thermal spraying methods such as flame spraying, low-temperature thermal spraying does not dissolve or melt the powder particles. Since the expanding process airflow is at a temperature significantly below the melting point of the powder particles, the heat input to the substrate material is low. Because the material properties associated with low heat load are largely maintained when introduced into the process airflow, low-temperature thermal spraying is suitable for material adhesion methods that form coatings, particularly for coating, repair, and corrosion protection.

[0006] In the past, low-temperature thermal spraying methods used helium as the process gas, particularly to form high-density, low-porosity material coatings. For example, compared to nitrogen, helium allows for significantly faster spraying at the same temperature, increasing the kinetic energy of the powder particles. Due to this increased kinetic energy, the resulting coating layer is low-porosity and has good bonding strength. However, the cost of manufacturing methods using helium is extremely high.

[0007] Furthermore, the technique of combining the low-temperature spray method with impact forging (shot peening) is well known. In this combined method, the ejected raw material particles are mixed with the supply raw material particles. The supply raw material particles, called forging particles, are harder than the actual raw material particles and are formed from other materials, such as high-quality steel or martensitic steel. The raw material particles include, for example, aluminum particles. The forging particles are harder than the actual raw material particles and are formed from other materials, such as high-quality steel or martensitic steel. The raw material particles include, for example, aluminum particles. In addition, the forging particles are accelerated through the process airflow and cause additional deformation of the raw material particles when they collide with the substrate surface. Impact forging (shot peening) has the advantage of reducing porosity and increasing the material density of the substrate surface formed without necessarily using expensive helium gas. However, the forging particles added to the applied raw material particles, or at least the remainder thereof, have the drawback of creating fragile heterogeneous defects in the sprayed molded body, particularly causing cracks and / or corrosion. [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to provide a method and apparatus for forming a low-temperature spray-molded article on a substrate surface, at least partially overcoming the aforementioned drawbacks of the conventional method. In particular, the low-temperature spray-molded article applied to the substrate surface by the method and apparatus is characterized by good mechanical properties (minimum porosity, high adhesive tensile strength, high tensile strength and / or high elongation at fracture) and good corrosion resistance.

[0009] The object of the present invention is solved by the invention of the low-temperature thermal spraying method described in claim 1 and the invention of the low-temperature thermal spraying apparatus described in claim 11. Furthermore, other problems to be solved by the present invention are described in the dependent claims and the following description. In particular, the object of the present invention is solved by a method, especially a method for forming a low-temperature thermal sprayed article and a low-temperature thermal spraying method applied to a material fixed to a substrate surface. The low-temperature thermal sprayed article is formed from raw material particles. [Means for solving the problem]

[0010] The cryogenic spraying method according to the present invention comprises a spraying step of injecting a process gas flow through a shrink-diffusion nozzle device. The shrink-diffusion nozzle device has a shrink region and a diffusion region in the flow direction of the process gas flow. For example, the shrink-diffusion nozzle device has a Laval nozzle. The process gas constituting the process gas flow includes, for example, gases such as nitrogen, carbon dioxide, helium, compressed air, water vapor, and argon. Similarly, a mixture of gases, particularly a mixture of nitrogen, can be used as the process gas.

[0011] The raw material particles used are aluminum, aluminum-based alloys (e.g., Al2024; Al6061; Al7050; Al7075; Al5083; Al6082), nickel, nickel-based alloys, magnesium, magnesium-based alloys, titanium, titanium-based alloys (e.g., Ti6Al4V; 3.7164), copper, copper-based alloys, zinc, zinc alloys, iron, iron-based alloys, cobalt, cobalt-based alloys, niobium, tantalum, and / or molybdenum. Other materials such as steel, especially high-alloy steel, can also be used.

[0012] The melting point of aluminum and aluminum alloys is approximately 600°C. The melting point of nickel and nickel alloys is approximately 1400°C. The melting point of magnesium and magnesium alloys is approximately 650°C. The melting point of titanium and titanium alloys is approximately 1600°C. The melting point of copper and copper alloys is approximately 1000°C. The melting point of zinc and zinc alloys is approximately 420°C. The melting point of cobalt and cobalt alloys is 1500°C, and the melting points of iron, iron alloys, and steel are approximately 1400°C to 1600°C.

[0013] Therefore, the raw material particles and forging particles have or are composed of at least one of aluminum, aluminum-based alloys, nickel, nickel-based alloys, magnesium, magnesium-based alloys, titanium, titanium-based alloys, copper, copper-based alloys, zinc, zinc alloys, iron, iron-based alloys, cobalt, cobalt-based alloys, niobium, tantalum and / or molybdenum.

[0014] Material particles and forging particles are introduced into the process airflow. The introduced particles (material particles and forging particles) are accelerated by the process airflow flowing through the nozzle device. The material particles and forging particles accelerated in the process airflow are sprayed onto the substrate surface. For this purpose, the process airflow is contracted or converged by the nozzle device so that the material particles can be attached to extremely precise locations on the substrate surface.

[0015] Material particles in the process airflow have a velocity that allows them to adhere to the substrate surface and form a thermal spray molded body. Forging particles in the process airflow have an extremely low velocity and therefore do not adhere to the substrate surface. The critical velocity of material particles that adhere to the substrate surface depends particularly on the temperature, size, and material composition of the material particles. The critical velocity corresponds to an increase in particle temperature. On the other hand, the particle velocity depends particularly on the particle size.

[0016] The forging particles have a median particle size larger than that of the material particles. Therefore, only the material particles can be used for the thermal spray molded body. In this case, the forging particles are not added to the thermal spray molded body, but are used to further deform the adhesion of the material particles during impact to the thermal spray molded body. As a result, thermal spray molded bodies with particularly low porosity and high density can be achieved. Furthermore, the thermal spray molded body exhibits good mechanical properties such as high adhesion tensile strength, high tensile strength and / or high elongation at break.

[0017] Furthermore, the raw material particles and the forged particles may contain the same material (e.g., standard Al6061), or the raw material particles and the forged particles may be manufactured from materials of the same group (e.g., both aluminum-based alloys).

[0018] The substrate is made from the same material or group of materials as the raw material particles. However, it is possible to form a thermal spray molded body on a substrate different from the raw material particles, resulting in a material from another group. For example, the low-temperature thermal spraying method of the present invention can be used to form a thermal spray molded body having aluminum and / or copper on a steel substrate.

[0019] In this specification, the group of raw material particles is understood to mean alloys that have the same base material (aluminum-based alloy, titanium-based alloy, nickel-based alloy, copper-based alloy, etc.) but differ in their additional composition. For example, an aluminum-based alloy (Al6061) may be used as the raw material particle (melting point 588°C), and a high-melting-point aluminum or aluminum-based alloy may be used as the forging particle.

[0020] By selecting material particles and forging particles from the same material or group of materials, it is possible to avoid the formation of foreign matter defects in the sprayed molded body, which weakens the body and particularly increases the risk of cracking and / or leads to corrosion. Accordingly, the sprayed molded body to which the low-temperature spraying method of the present invention is applied exhibits good mechanical strength, in particular high adhesive tensile strength, high tensile strength and / or high elongation at break and / or good corrosion resistance.

[0021] Therefore, the low-temperature spraying method of the present invention is particularly suitable for repair applications. In particular, the defects of titanium or aluminum parts used in the aviation industry can be repaired quickly and economically using the low-temperature spraying method of the present invention. In one embodiment of the present invention, the material particles have a first particle temperature, the forged particles have a second particle temperature, and the first particle temperature is higher than the second particle temperature. Therefore, a highly pure sprayed molded body of the raw material particles can be formed.

[0022] In one embodiment of the present invention, the process air flow in the diffusion region of the nozzle device has a temperature below the melting point of the raw material particles. In particular, the temperature of the process air flow is at a level where the material particles introduced into the process air flow are not melted and not sufficiently melted even when transported by the process air flow. The raw material particles and / or the forged particles are preferably introduced into the process air flow in the contraction region of the nozzle device. Therefore, both the material particles and the forged particles can be injected and accelerated together with the process air flow through the nozzle device.

[0023] Similarly, the raw material particles and / or the forged particles can be introduced into the diffusion region of the nozzle device. Therefore, both types of particles can be introduced into the already accelerated process air flow and accelerated by the process air flow.

[0024] Furthermore, a first portion of the particles (raw material particles and / or forged particles) can be introduced into the contraction region of the nozzle device, and a second portion of the particles (raw material particles and / or forged particles) can be introduced into the diffusion region of the nozzle device. For example, the raw material particles can be introduced into the contraction region of the nozzle device, and the forged particles can be introduced into the diffusion region of the nozzle device. By the position of introduction, the length of time the particles stay in the process air flow can be determined, and in particular, the temperature and / or the velocity of the particles when colliding with the substrate surface can be determined.

[0025] For example, particles (raw material particles and / or forging particles) are introduced into a supported gas. For this purpose, the supported gas transports the particles (raw material particles and / or forging particles) or particle mixture from a corresponding container, and the particles / particle mixture are supplied to the corresponding area of ​​the nozzle device. The supported gas is the same as the process gas, but the supported gas and the process gas may be different. The supported gas used may be nitrogen, carbon dioxide, helium, compressed air, water vapor, argon, etc. Alternatively, a mixture of the above gases can be used as the supported gas.

[0026] In one embodiment of the present invention, the particles introduced into the process airflow include 15% to 40% by volume of raw material particles and 60% to 85% by volume of forging particles. Alternatively, the particles introduced into the process airflow may include 20% to 35% by volume of raw material particles and 55% to 80% by volume of forging particles. The aforementioned ratio of raw material particles to forging particles allows for rapid thermal spray molding and good mechanical properties.

[0027] The raw material particles have a median particle size within the particle size ranges of 5 μm to 65 μm, 15 μm to 50 μm, 20 μm to 45 μm, or 30 μm to 40 μm. Larger refined particles have a median particle size within the particle size ranges of 60 μm to 500 μm, 90 μm to 350 μm, 150 μm to 320 μm, or 180 μm to 300 μm. The median particle size is usually expressed as the median particle size D50 value of the particle size distribution.

[0028] In one embodiment of the present invention, raw material particles and forging particles are introduced into the process airflow as a particle mixture. For example, both particles, i.e., raw material particles and forging particles, are supplied together into the process airflow by a particle injection device whose end is connected to the contraction region of a nozzle device. In this case, the ratio of raw material particles to forging particles is determined by the particle mixture supplied to the particle injection device. The particle mixture can be pre-mixed and supplied from a container containing the particle mixture, or the particle mixture can be mixed by the particle injection device. For this purpose, two separate containers are provided, one for the raw material particles and the other for the forging particles. The composition of the particle mixture in this mixing method can be controlled by corresponding values.

[0029] Similarly, the raw material particles and the forging particles can be introduced into the process airflow separately. For this purpose, for example, two particle injection devices can be provided.

[0030] In one embodiment of the present invention, the raw material particles are accelerated to a velocity range of 200 m / s to 2000 m / s, 500 m / s to 1500 m / s, or 800 m / s to 1000 m / s. Similarly, the raw material particles are accelerated to a velocity range of 200 m / s to 700 m / s or 300 m / s to 500 m / s. This velocity range is selected so that the raw material particles adhere to the substrate surface.

[0031] The forging particles are accelerated to speed ranges such as 100 m / s to 600 m / s, 300 m / s to 550 m / s, or 450 m / s to 500 m / s. Similarly, the forging particles can be accelerated to speed ranges such as 100 m / s to 400 m / s or 150 m / s to 300 m / s. The speed of the forging particles is determined in particular by the particle dimensions. The dimensions of the forging particles are set to achieve a speed at which the forging particles do not adhere to the substrate surface.

[0032] The raw material particles, when impacted onto the substrate surface, have a temperature range of 20°C to 800°C, 25°C to 600°C, 100°C to 500°C, 150°C to 400°C, or 200°C to 300°C. The temperature at the time of impact onto the substrate surface is understood to mean the temperature of the particles themselves before deformation due to impact with the substrate surface.

[0033] The particle temperature upon impact with the substrate surface is particularly influenced by the particle temperature before and during introduction into the process airflow. Further factors include the particle size and introduction time into the process airflow. The time spent in the process airflow is influenced by the particle's injection position, injection direction, and / or injection velocity.

[0034] In particular, the cryogenic spraying method of the present invention comprises a step of controlling the cooling of the raw material particle temperature and / or the forging particle temperature, especially before and / or during introduction into the process airflow. The raw material particles and forging particles are temperature-controlled together (for example, when they are introduced into the process airflow as a particle mixture) or individually (for example, when they are introduced into the process airflow individually).

[0035] In particular, particles can be supplied to process airflows in temperature ranges of 0°C to 400°C, 10°C to 250°C, or 25°C to 200°C. When the temperatures of the raw material particles and the forging particles are controlled individually, for example, when introduced into the process airflow, the forging particles will have a temperature lower than that of the raw material particles.

[0036] In one embodiment of the present invention, the process gas constituting the process airflow is nitrogen or a nitrogen mixture. Since nitrogen is inexpensive (compared to, for example, helium), it can reduce the manufacturing cost of forming high-density thermal spray molded articles with low porosity. Similarly, other gases such as carbon dioxide, helium, compressed air, water vapor, argon, and / or gas mixtures can be used as the process gas.

[0037] In another embodiment of the present invention, the process airflow upstream of the shrink-diffuse nozzle device is heated to a temperature range of 200°C to 1400°C or 500°C to 1200°C. For this purpose, a heating device is provided. The velocity (and particle velocity) of the supported airflow downstream of the nozzle device is affected by the temperature upstream of the nozzle device. Furthermore, the process airflow upstream of the shrink-diffuse nozzle device has a pressure range of 5 bar to 100 bar or 40 bar to 60 bar. The velocity of the process airflow downstream of the nozzle device is affected by the aforementioned pressure.

[0038] Furthermore, the object of the present invention is to be solved by a manufacturing apparatus for low-temperature thermal spray molded articles applied to a substrate surface. The low-temperature thermal spray molding apparatus according to the present invention is configured to carry out the low-temperature thermal spraying method described above.

[0039] The low-temperature thermal spray molding apparatus has a heating device that controls the temperature of the process airflow (e.g., nitrogen or a nitrogen mixture). The heating device is located downstream of a nozzle device which has a shrinkage region and a diffusion region. The diffusion region is located downstream of the shrinkage region in the flow direction. The nozzle device is also configured to determine and accelerate the flow direction of the temperature-controlled process airflow. The nozzle device directs and accelerates the temperature-controlled process airflow.

[0040] Furthermore, the low-temperature thermal spray molding apparatus includes at least one particle injection device for introducing raw material particles and forging particles into the process airflow.

[0041] In particular, the particle injection device is configured to introduce material particles and / or training particles into the contraction region of the nozzle device. Similarly, the particle injection device is configured to introduce material particles and / or training particles into the diffusion region of the nozzle device. Furthermore, the particle injection device can introduce a first portion of the particles (material particles and / or training particles) into the contraction region of the nozzle device, while introducing a second portion of the particles (material particles and / or training particles) into the diffusion region of the nozzle device.

[0042] Furthermore, at least one particle injection device is configured to control, in particular, the temperature of the material particles and / or the forging particles, especially to cool them.

[0043] In one embodiment of the present invention, the particle injection device includes a particle injection device having particle guide grooves formed by groove walls and controlling the temperature of the particles, particularly cooling the particle temperature. The groove walls have at least one cooling groove for guiding a refrigerant, particularly cooling water. The thermal performance and particle temperature can be set by the temperature and flow rate of the refrigerant.

[0044] Furthermore, the particle injection device is configured to introduce a mixture of raw material particles and / or training particles into the diffusion or contraction region of the nozzle device. For this purpose, pre-prepared mixed particles contained in a container can be extracted from the container. Similarly, mixed particles can be prepared first upstream of the particle injection device. For this purpose, two different containers can be provided, one for the raw material particles and the other for the training particles. The composition of the mixed particles can be controlled by corresponding measuring devices (e.g., a constant-volume feeder equipped with a transport disc, transport screw, etc.).

[0045] The low-temperature thermal spray molding apparatus comprises at least two particle injection devices: a first particle injection device for introducing material particles into the diffusion region or shrink region of a shrink-diffusion nozzle, and a second particle injection device for introducing forging particles into the diffusion region or shrink region of the shrink-diffusion nozzle.

[0046] Furthermore, at least one particle injection device is configured to introduce material particles and / or forging particles into the process airflow substantially in the flow direction of the process airflow (particularly in the diffusion and / or contraction regions of the contraction-diffusion nozzle). In this case, the direction of the process airflow and the injection direction of the introduced particles form an angle α corresponding to 0 degrees.

[0047] Furthermore, at least one particle injection device is configured to introduce material particles and / or grinding particles into the process airflow (particularly the diffusion and / or contraction regions of the nozzle device) at an angle α other than angle 0, in particular substantially lateral to the direction of the process airflow (angle α is approximately 90 degrees). Angle α can be in the range of 0 to 90 degrees, in the range of 30 to 60 degrees, or approximately 45 degrees.

[0048] Furthermore, the low-temperature thermal spray molding apparatus includes a process gas supply device configured to supply process gas to a heating device and / or at least one particle emission device. [Brief explanation of the drawing]

[0049] Embodiments of the present invention will be described in detail below with reference to the attached drawings. [Figure 1] Flowchart showing the steps of the low-temperature thermal spray molding method according to the present invention [Figure 2] Cross-sectional diagram showing the process of low-temperature thermal spray molding using the structure of a thermal spray molded product. [Figure 3A] Cross-sectional view showing one embodiment of a low-temperature thermal spray molding apparatus. [Figure 3B] Cross-sectional view showing another embodiment of the low-temperature thermal spray molding apparatus. [Figure 3C] Cross-sectional view showing another embodiment of the low-temperature thermal spray molding apparatus. [Figure 4] Cross-sectional view showing different embodiments of a low-temperature thermal spray molding apparatus. [Figure 5] Cross-section of a particle injector [Figure 6] Graph showing the relationship between speed and temperature [Modes for carrying out the invention]

[0050] Figure 1 shows a flowchart illustrating the following steps of the low-temperature thermal spraying method 1000 for the low-temperature thermal spray molded body 10 shown in Figure 2.

[0051] First, in the ejection process 1100, the shrinking diffusion nozzle device (abbreviated as "nozzle device") 110 ejects a process airflow 20 {for example, nitrogen gas (N2 or a mixture of N2)}. The temperature of the process airflow 20 has a temperature range that inhibits the melting of raw material particles introduced into the process airflow 20.

[0052] The raw material particles 14, which include raw material particles and forging particles 16, are introduced into the process airflow 20 in the introduction step 1200. For example, the raw material particles 14 are introduced into the process airflow 20 in the contraction region of the nozzle device 110 (introduction step 1200). Next, the raw material particles 14 and forging particles 16 are accelerated by the process airflow supplied through the nozzle device 110 (acceleration step 1300).

[0053] The raw material particles 14 and forging particles 16, accelerated by the process airflow 20, are then sprayed or ejected toward the substrate surface 30 (injection process 1400). For this purpose, the process airflow 20 is focused toward the substrate surface 30 of a specific target. The injection process is shown in detail in Figure 2. In order to form a low-temperature sprayed molded body 10 that adheres to the substrate surface 30, the raw material particles 14 have a constant velocity (e.g., 200 m / sec to 2000 m / sec) (Figures 2B and 2C). The larger the forging particles 16 carried by the process airflow 20, the lower their velocity (e.g., 100 m / sec to 600 m / sec) is compared to the forging particles 16 that adhere to the substrate surface 30 (Figure 2C). The forging particles 16 collide with the substrate surface 30, increasing the density of the substrate material already fixed to the substrate surface 30 (i.e., further deforming the fixed raw material particles 14), and the larger forging particles 16 detach from the substrate surface 30. For example, the forging particles 16 that have detached from the substrate surface 30 can be captured and reused or reprocessed.

[0054] The forged particles 16 have a median particle size that is larger than the median particle size of the raw material particles 14. For example, the forged particles 16 are 3 times, at least 4 times, at least 5 times, at least 8 times, at least 10 times, or at least 15 times (based on particle diameter) larger than the raw material particles 14. Furthermore, the raw material particles 14 and the forged particles 16 are manufactured from the same material or the same group of materials. The materials or group of materials that can be manufactured are aluminum, aluminum-based alloys, nickel, nickel-based alloys, magnesium, magnesium-based alloys, titanium, titanium-based alloys, magnesium, magnesium-based alloys, titanium, titanium-based alloys, copper, copper-based alloys, zinc, zinc-based alloys, iron, iron-based alloys, cobalt, cobalt-based alloys, niobium, tantalum, and / or molybdenum. Other materials such as steel, especially high-alloy steel, can also be used.

[0055] Furthermore, the cryogenic spraying method 1000 may include control steps, particularly steps to control the temperature of the raw material particles 14 and / or the forging particles 16 before and / or during the introduction of the process airflow 20 (introduction step 1200), especially cooling steps. Similarly, the cryogenic spraying method 1000 may include steps to control the temperature of the process gas upstream of the nozzle device (110), for example, a heating device. In addition to the quality (or flow rate) of the process gas, the temperature of the process airflow also affects its pressure. For example, the process airflow 20 may be heated to a temperature range of 200°C to 1400°C and / or controlled to a pressure range of 5 bar to 100 bar upstream of the nozzle device (110).

[0056] Figures 3A, 3B, and 3C are cross-sectional views showing different embodiments of the low-temperature spray molding apparatus 100 for the low-temperature spray molded body 10. In the low-temperature spray molding apparatus 100 shown in Figures 3A, 3B, and 3C, multiple particles (particle mixture 18, raw material particles 14, and / or forging particles 16) are introduced into the shrinkage region 114 of the nozzle device 110, which is positioned substantially transversely (angle α = approximately 90 degrees) to the flow direction of the process airflow 20. In the low-temperature spray molding apparatus 100 shown in Figure 4, multiple particles (particle mixture 18, raw material particles 14, and / or forging particles 16) are introduced into the shrinkage region 114 of the nozzle device 110, which is positioned substantially in the same direction (angle α = approximately 0°C) to the flow direction of the process airflow 20.

[0057] Figures 3A, 3B, 3C, and 4 show cross-sectional views of a heater 105 that introduces multiple particles into the contraction region 114 of the nozzle device 110. However, unlike the contraction region 114 of the nozzle device 110, the particle injection device 200 or particle injector 210 can be arranged in a manner that introduces multiple particles (raw material particles 14, forging particles 16, and / or particle mixture 18) into the diffusion region 112 of the nozzle device 110. Alternatively, a first portion of the multiple particles (raw material particles 14, forging particles 16, and / or particle mixture 18) may be introduced into the contraction region 114 of the nozzle device 110, while a second portion of the multiple particles (raw material particles 14, forging particles 16, and / or particle mixture 18) may be introduced into the diffusion region 112 of the nozzle device 110.

[0058] The nozzle device 110 shown in Figures 3A, 3B, and 3C is used to generate a low-temperature spray-molded body 10 on the substrate surface 30. The low-temperature spray-molded body 10 can be applied in thicknesses ranging from less than a millimeter to several centimeters. For example, even if defects 32 such as scratches or cracks are formed on the substrate, the application of the low-temperature spray-molded body 10 can close and correct the defects 32.

[0059] The low-temperature thermal spray molding apparatus 100 includes a heater 105 into which process gas is introduced via an optional gas supply device 300. The gas supply device 300 can control the characteristics of the process airflow, particularly the flow rate. For this purpose, a corresponding control device, in particular a flow controller 302, can be provided.

[0060] The temperature of the process gas is controlled by a heating device 105 located upstream of the nozzle device 110. For this purpose, a corresponding heater 107 is provided, for example, to specifically control the temperature of the process gas. The process gas 20 passing through the nozzle device 110, which has a contraction region 112 and a diffusion region 114, is accelerated through the nozzle device 110. The flow velocity of the process gas downstream of the nozzle device 110 can be controlled upstream of the nozzle device 110 by controlling the temperature and / or arbitrary pressure of the process gas 20.

[0061] A carrier gas is introduced from at least one particle injection device 200 and a carrier gas supply device 305, which are provided to introduce the raw material particles 14 and the refined particles 16 into the process airflow 20 (e.g., the diffusion region 114 of the nozzle device 110). The carrier gas is used to introduce the raw material particles 14 and the refined particles 16 into the process airflow 20. The carrier gas supply device 305 can control the carrier airflow 22, particularly its flow velocity. For this purpose, at least one corresponding controller, in particular flow controllers 307, 307a, and 307b, are provided. The quality of the particles (raw material particles 14, refined particles 16, and / or particle mixture 18) introduced into the process airflow 20 via the carrier gas is controlled by at least one metering device, such as a conveying disc or a conveying screw.

[0062] The particle injection apparatus 200 illustrated in Figure 3A comprises a container 228 having a particle mixer 18 that contains raw material particles 14 and forging particles 16. The particle mixture 18 is supplied via a particle injection nozzle 210 to a process airflow 20, for example, a contraction region 114 of a nozzle device 110, by a carrier airflow 22. The particles introduced into the carrier airflow 22 are captured and accelerated by the process airflow 20. The process airflow 20 carrying the particles is converged or focused in the contraction region 114 and directed toward the substrate surface 30. The structure of the low-temperature sprayed molded body 10 is formed as described with respect to Figure 2.

[0063] The particle injection device 200 illustrated in Figure 3B comprises two separate containers: a first container 224 for containing raw material particles 14 and a second container 226 for containing refined particles 16. The first container 224 and the second container 226 are connected to a particle injector 210 that supplies particles from the first container 224 and the second container 226 into the process airflow 20 (in this embodiment, the contraction region 114 of the nozzle device 110). This allows the ratio of refined particles 16 to raw material particles 14 to be changed. For example, the particles introduced into the process airflow 20 may contain 15% to 40% by volume of raw material particles 14 and 60% to 85% by volume of refined particles 16.

[0064] The raw material particles 14 and forging particles 16 introduced into the nozzle device 110 are captured and accelerated by the process airflow 20. The process airflow 20 carrying the particles is then converged and flows toward the substrate surface 30. The structure of the low-temperature sprayed molded body 10 is achieved as described in Figure 2.

[0065] The particle injection apparatus 200, further illustrated in Figure 3C, comprises two individual containers, a first container 224 and a second container 226, each assigned to at least one particle injection unit 210. The raw material particles 14 are contained in the first container 224 and then supplied to the first particle injection unit 210. The first particle injection unit 210 supplies the raw material particles 14 to the process airflow 20. As illustrated, the raw material particles 14 are transported by a carrier airflow 22, which is controlled by a controller 307a. For example, the quality of the raw material particles 14 to be introduced is controlled by a weighing device.

[0066] The forging particles 16 are contained in a second container 226 and then supplied to a second particle injector 210. The second particle injector 210 supplies the forging particles 16 to a carrier airflow 22. The example forging particles 16 are transported by the carrier airflow 22. The carrier airflow 22 is controlled by a controller 307b. For example, the quality of the forging particles 16 being introduced is controlled by a weighing device.

[0067] The introduction positions of the forging particles 16 and the raw material particles 14 can be substantially the same, or the forging particles 16 can be introduced into the process airflow upstream or downstream of the raw material particles 14. For example, the raw material particles 14 and the forging particles 16 can be introduced into the contraction region 114 of the nozzle device 110. Similarly, the raw material particles 14 can be supplied to the contraction region 112 of the nozzle device 110, and the forging particles 16 can be supplied to the diffusion region 114.

[0068] The particle injection device 200 shown in Figure 3C can introduce raw material particles 14 and forging particles 16 individually by particularly changing the ratio of raw material particles 14 to forging particles 16. The raw material particles 14 and forging particles 16 introduced into the process airflow (particularly the nozzle device 110) are captured and accelerated by the process airflow 20. The process airflow 20 carrying the particles is then contracted and directed toward the substrate surface 30. The structure of the low-temperature sprayed molded body 10 is formed as described in Figure 2.

[0069] Figure 4 shows another embodiment of the cryogenic spray molding apparatus 100 for a cryogenic spray-molded body 10. The structure of the embodiment shown in Figure 4 substantially corresponds to the structure of the container 228 that contains the pre-mixed particle mixture 18 introduced into the process airflow 200 in the shrinking region 114 of the nozzle device 110, as shown in Figure 3A. The cryogenic spray molding apparatus 100 shown in Figure 4 has substantially different injection directions for the raw material particles 14 and the densifying particles 16 or particle mixture 18, which are directed in the direction of the process airflow 20. The cryogenic spray molding apparatus 100 shown in Figure 4 is configured to include separate containers 224, 226 and / or at least two separating particle injectors 210 (similar to Figure 3C). Similarly, it is also possible to introduce the raw material particles 14 and densifying particles 16 into the process airflow 20 by providing at least one particle injector 210 directed in the direction of the process airflow 20 and at least one particle injector 210 directed laterally to the direction of the process airflow 20.

[0070] In one embodiment of the present invention, the injection positions of the raw material particles 14, the forging particles 16, and / or the particle mixture 18 can be changed by changing the position of at least one particle injector 210, particularly in relation to the process airflow 20.

[0071] In particular, the particle injector 210 shown in Figure 5 is configured to control the temperature of the raw material particles 14 and / or the forging particles 16, and especially to cool them. Specifically, the particle injector 210 is configured to be temperature controllable or coolable. In this way, the temperature of the raw material particles 14, the forging particles 16 and / or the particle mixture 18 can be controlled, especially before and during introduction into the process airflow 20. When two separate particle injectors 210 (e.g., Figure 3C) are provided, the temperatures of the raw material particles 14 and the forging particles 16 can be controlled individually.

[0072] The particle injector 210 shown in Fig. 5 includes a particle guiding groove 212 formed by a central wall 214 and provided at the center. The central wall 214 includes at least one cooling groove 216 for guiding a coolant, particularly cooling water. For example, the central wall 214 can be formed in a double-wall structure to form a coolant groove between the radially inner wall and the radially outer wall. The coolant can be supplied to the particle injector 210 from a coolant inlet 226a and discharged from the particle injector 210 through a coolant outlet 226b.

[0073] Fig. 6 is a graph showing the velocity-temperature characteristics indicating the related characteristics of the particle temperature and the particle velocity for attaching particles to the substrate surface. The solid line represents the critical velocity V crit16 and the upper velocity V eros16 of the forged particles 16. The dotted line represents the critical velocity V crit14 and the upper velocity V eros14 of the raw material particles 14. If the raw material particles 14 and the forged particles 16 collide with the substrate surface at velocities and temperatures exceeding the upper velocities V eros14 and V eros16 respectively, the low-temperature sprayed molded body 10 will not be formed. Instead, an erosion effect will occur on the substrate surface.

[0074] When the temperature-dependent critical velocity V eros14 or V eros16 is exceeded, the raw material particles 14 and the forged particles 16 will adhere to the substrate surface and the sprayed molded body 10 will be formed. If the critical velocity V eros14 or V eros16 is not reached, the sprayed molded body 10 will not be formed. The raw material particles 14 sprayed at the velocity and temperature indicated by the typical point (in this embodiment, for example, about 700 m / s and 240 °C) will adhere to the substrate surface. In contrast, the forged particles 16 sprayed at the velocity and temperature (in this embodiment, for example, about 500 m / s and 70 °C) will not adhere to the substrate surface but rather contribute to the solidification of the sprayed molded body 10. The velocity-temperature characteristics shown in Fig. 6 are merely illustrative. The critical velocity and the upper velocity particularly depend on the particle material used.

Explanation of Reference Numerals

[0075] 10...Cryogenic spray-molded body, 12...Feed material, 14...Raw material particles, 16...Forging particles, 18...Particle mixture, 20...Process airflow, 22...Carrier airflow, 30...Substrate surface, 32...Defects, 40...Coolant, 100...Cryogenic spray molding apparatus, 105...Heating apparatus, 107...Heater, 110...Nozzle apparatus, 112...Diffusion region, 114...Shrinkage region, 200...Particle injection apparatus, 210...Particle injector, 212...Particle guide groove, 216...Cooling groove, 216a...Coolant inlet, 216b...Coolant outlet, 224, 226, 228...Container, 300...Process gas supply apparatus, 302...Flow controller, 305... Carrier gas supply device, 307, 307a, 307b... Flow controller, 1100... Injection process, 1200... Introduction process, 1300... Acceleration process, 1400... Particle direction, T P ·Particle temperature, V P ·Particle velocity, V crit14 ·Critical velocity of raw material particles, V crit16 ··Forging particle critical velocity, V eros14 ...Raw material particle top velocity, V eros16 ··Forging particle velocity,

Claims

1. A method for forming a thermal spray molded body (10) on a substrate surface (30) by ejecting raw material particles (14) of a supply raw material (12) onto the substrate surface (30), particularly in a low-temperature thermal spray method (1000), A spraying process (1100) in which a process airflow (20) is ejected toward the substrate surface (30) through a shrinking diffusion nozzle device (110), An introduction process (1200) for introducing raw material particles (14) and forging particles (16) into the process airflow (20), An acceleration step (1300) accelerates the raw material particles (14) and the forging particles (16) with a process airflow (20) supplied by a shrinking diffusion nozzle device (110), The process includes an injection process (1400) in which raw material particles (14) and forging particles (16), accelerated by a process airflow (20), are injected onto the substrate surface (30). The raw material particles (14) have a speed at which they adhere to the substrate surface (30) and form the thermal spray molded body (10), while the forging particles (16) have an ultra-low speed at which they do not adhere to the substrate surface (30). The refined particles (16) have a median particle size that is larger than the median particle size of the raw material particles (14). A low-temperature thermal spraying method (1000) characterized in that the raw material particles (14) and the forging particles (16) are made of the same material or are formed from the same group of materials.

2. The introduction step (1200) of raw material particles (14) is performed in the contraction region (114) and / or the diffusion region (112) of the contraction diffusion nozzle (110), and / or The low-temperature thermal spraying method (1000) according to claim 1, wherein the introduction step (1200) of the forging particles (16) is performed in the contraction region (114) and / or the diffusion region (112) of the contraction diffusion nozzle (110).

3. The raw material particles (14) and forging particles (16) introduced into the process airflow (20) consist of 15% to 40% by volume of raw material particles (14) and 60% to 85% by volume of forging particles (16), or The raw material particles (14) have a median particle size in the range of 5 μm to 65 μm, 15 μm to 50 μm, 20 μm to 45 μm, or 30 μm to 40 μm. The low-temperature thermal spraying method (1000) according to claim 1 or 2, wherein the forging particles (16) have a median particle size in the range of 60 μm to 500 μm, 90 μm to 350 μm, 150 μm to 320 μm, or 180 μm to 300 μm.

4. A low-temperature thermal spraying method (1000) according to any one of claims 1 to 3, comprising a mixing introduction step of introducing raw material particles (14) and forging particles (16) as a particle mixture into a process airflow (20), or an individual introduction step of introducing raw material particles (14) and forging particles (16) individually into a process airflow (20).

5. A process of accelerating raw material particles (14) to a speed range of 200 m / s to 2000 m / s, 500 m / s to 1500 m / s, 800 m / s to 1000 m / s, 200 m / s to 700 m / s, or 300 m / s to 500 m / s and / or A low-temperature thermal spraying method (1000) according to any one of claims 1 to 4, comprising the step of accelerating the forging particles (16) to a speed range of 100 m / s to 600 m / s, 300 m / s to 550 m / s, 450 m / s to 500 m / s, 100 m / s to 400 m / s, or 150 m / s to 300 m / s.

6. A process of impacting a substrate surface (30) with raw material particles (14) in a temperature range of 200°C to 800°C, 25°C to 600°C, 100°C to 500°C, 150°C to 400°C, or 200°C to 300°C and / or A low-temperature thermal spraying method (1000) according to any one of claims 1 to 5, comprising the step of impacting a substrate surface (30) with forging particles (16) in the temperature ranges of 25°C to 300°C, 30°C to 200°C, 50°C to 120°C, and 80°C to 100°C.

7. A low-temperature thermal spraying method (1000) according to any one of claims 1 to 6, comprising a step of controlling the temperature of raw material particles (14) and / or forging particles (16) to within the temperature range of 0°C to 400°C, 10°C to 250°C, or 25°C to 200°C before and / or during introduction into the process airflow (20), and particularly cooling them.

8. A low-temperature thermal spraying method (1000) according to any one of claims 1 to 7, wherein the raw material particles (14) and forging particles (16) include or consist of at least one of aluminum, aluminum-based alloys, magnesium, magnesium-based alloys, zinc, zinc-based alloys, nickel, nickel-based alloys, titanium, titanium-based alloys, copper, copper-based alloys, iron, iron-based alloys, cobalt, cobalt-based alloys, niobium, tantalum and / or molybdenum.

9. The cryogenic thermal spraying method (1000) according to any one of claims 1 to 8, wherein the process gas constituting the process airflow (20) is nitrogen, carbon dioxide, helium, compressed air, water vapor and / or argon.

10. A heating step and / or heating the process airflow (20) upstream of the shrinking diffusion nozzle device (110) to a temperature range of 200°C to 1400°C or 500°C to 1200°C. A cryogenic spraying method (1000) according to any one of claims 1 to 9, comprising a pressure holding step of maintaining the pressure range of the process airflow (20) upstream of the shrinkage diffusion nozzle device (110) to 5 bar to 100 bar or 40 bar to 60 bar.

11. In a low-temperature thermal spraying apparatus (100) that performs a low-temperature thermal spraying method (1000) according to any one of claims 1 to 10 to form a thermal spray molded body (10) on a substrate surface (30), A heating device (105) that controls the temperature of the process airflow (20), The system includes a shrink-diffusion nozzle device (110) that determines and accelerates the injection direction of a temperature-controlled process airflow (20) having a diffusion region (112) and a shrink region (114), The shrinking diffusion nozzle device (110) includes at least one particle injection device (200) that introduces raw material particles (14) and / or forging particles (16) into the process airflow (20), A low-temperature thermal spray molding apparatus (100) characterized in that at least one particle injection device (200) controls and, in particular, cools the temperature of the raw material particles (14) and / or the forging particles (16).

12. At least one particle injector (200) comprises a temperature-controllable, and in particular, coolable, particle injector (210), The particle injector (210) is equipped with a particle guide groove (212) formed by a groove wall (214), The low-temperature thermal spray molding apparatus (100) according to claim 11, wherein the groove wall (214) comprises at least one cooling groove (216) through which a coolant, in particular cooling water, is circulated.

13. The particle injection device (200) introduces a particle mixture containing raw material particles (14) and forging particles (16) into the contraction region (112) or contraction region (114) of the contraction diffusion nozzle device (110) and / or A low-temperature thermal spray molding apparatus (100) according to claim 11 or 12, comprising two particle injection devices: a first particle injection device (200) for introducing raw material particles (14) into the shrinking region (112) or shrinking region (114) of a shrinking diffusion nozzle device (110), and a second particle injection device (200) for introducing forging particles (16) into the shrinking region (112) or shrinking region (114) of the shrinking diffusion nozzle device (110).

14. At least one particle injection device (200) introduces raw material particles (14) and grinding particles (16) into the shrinking region (112) and / or shrinking region (114) of the shrinking diffusion nozzle device (110) in substantially the flow direction of the process airflow (20), A low-temperature thermal spray molding apparatus (100) according to any one of claims 11 to 13, wherein at least one particle injection device (200) introduces raw material particles (14) and / or forging particles (16) into the shrink region (112) and / or shrink region (114) of a shrink diffusion nozzle device (110) at an angle α with respect to the flow direction of the process airflow (20), particularly substantially lateral.

15. A low-temperature thermal spray molding apparatus (100) according to any one of claims 11 to 14, comprising a heating device (105) and / or a process gas supply device (300) for supplying process gas to at least one particle injection device (200).

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