Preparation method for preparing honeycomb-shaped porous structure metal material based on cold spraying and material of honeycomb-shaped porous structure metal material

Abstract

The invention belongs to the field of metal material processing, and relates to a honeycomb porous structure metal material prepared on the basis of cold spraying and a preparation method of the honeycomb porous structure metal material, metal hydride is used as a cold spraying raw material, so that spraying powder particles present different attachment deviations, and a honeycomb structure is formed. The preparation method specifically comprises the following steps: S1, preparing metal hydrogenated powder; s2, cold spraying forming is conducted; and S3, dehydrogenation treatment. According to the preparation method, the requirements of cold spraying machining, especially the high critical spraying rate needed by powder and the like are lowered, the feasibility of cold spraying machining of metal materials is widened, and compared with preparation methods such as casting, powder metallurgy and additive manufacturing, the preparation method has the beneficial effects of being rapid, continuous and short in process. Compared with a conventional metal material processed through cold spraying, the porous structure metal material prepared through the method has higher electromagnetic shielding performance and can be applied to the field of electromagnetic shielding at low cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material processing, and in particular relates to a preparation method of a honeycomb porous structure metal material based on cold spraying and the porous structure metal material obtained. Background Art

[0002] Porous metal materials are widely used in catalysis, radiators, evaporators, sound insulation materials, biomedicine, lightweight structural materials and other fields because of their advantages such as light weight and high specific surface area, combined with the excellent properties of the matrix material. Traditional methods for manufacturing porous structures include casting, powder metallurgy and additive manufacturing. However, traditional methods such as casting and powder metallurgy have limitations in size, shape, porosity control and integrated multifunctional structures. Although additive manufacturing methods such as selective laser melting can improve the shape design and mechanical properties of porous metal materials, they still have defects such as low molding efficiency, discontinuous manufacturing process and harsh atmosphere requirements when manufacturing porous metal materials with large sizes. Therefore, although porous metal materials have a huge application scenario, the preparation process of this material is complicated and the cost is high.

[0003] Cold spraying is an emerging solid-state additive manufacturing method in which powders are deformed and consolidated under conditions below the melting point. Metal powder particles with a micron size of about 5 to 75 μm are accelerated by high-speed inert gas under heating conditions below 1000°C, and reach a critical deposition rate after passing through the de Laval nozzle. They impact the substrate under completely solid conditions, and bond and deposit through severe plastic deformation at the interface between the metal particles and the substrate. This method has the advantages of fast forming, less oxidation, and avoidance of various defects related to melting. It is currently a commonly used metal rapid manufacturing method. Because of the high processing efficiency of cold spraying, low requirements for powder sphericity, and low cost, researchers have developed a method for manufacturing porous metal materials based on cold spraying. By first mixing titanium with magnesium and aluminum elements and then cold spraying to prepare a block, the low-melting-point magnesium and aluminum elements are removed by vacuum heating to obtain porous titanium. Furthermore, by regulating the gas temperature and particle impact velocity, a porous Ti-6Al-4V alloy coating with a porosity of 30% was prepared. However, the holes in the materials prepared by the above methods are internal through holes, and such methods cannot prepare honeycomb porous structure metal materials. Therefore, existing technologies including casting, powder metallurgy, additive manufacturing and cold spraying cannot quickly and short-process prepare honeycomb porous structure metal materials. Summary of the invention

[0004] In view of the huge application potential of honeycomb porous structure materials, there is an urgent need to develop a fast, short-process, and low-cost preparation technology for preparing honeycomb porous structure metal materials based on cold spraying. The present invention provides a honeycomb porous structure metal material based on titanium hydride powder and a preparation method thereof.

[0005] The first aspect of the present invention provides a method for preparing a honeycomb porous structure metal material based on titanium hydride powder, comprising the following steps:

[0006] S1. Prepare metal hydride powder, specifically:

[0007] S11, placing a metal block in an atmosphere furnace, heating the metal block to a first set temperature in a high-purity H2 atmosphere at 1 atmosphere pressure, keeping the temperature for 2 to 3 hours, and then cooling the furnace to room temperature to obtain a metal hydride block;

[0008] S12, pouring the metal hydride block into a planetary ball mill and ball milling according to preset ball milling parameters, taking out the ball milled powder and sieving it to obtain metal hydride powder with a micron particle size; the ball milling parameters include: the ball milling atmosphere is 1 atmosphere of high-purity argon gas, the ball-to-material ratio is 1 to 2:1, the rotation speed is 400 to 500 rpm, and the ball milling time is 10 to 15 minutes;

[0009] S2, cold spray molding: the metal hydride powder prepared in S1 is combined with a substrate under inert gas acceleration to form surfaces with three structures: slope, curved and plane. During the continuous cold spraying process, the boundary of the metal hydride powder heats up and undergoes dehydrogenation during the deformation process at a high strain rate, forming powder particles with surface toughness. When the powder particles impact the curved surface and the slope structure, the tough phase of the powder particles has a high deposition efficiency on the slope and curved surface, but is difficult to deposit on the plane. After subsequent repeated cold spraying processes, the surface of the slope structure and the curved surface structure is continuously deposited and increased to form a wall structure, and the surface of the plane structure forms a pore structure, finally forming a hydrogenated porous structure metal material;

[0010] S3, dehydrogenation treatment: heating the hydrogenated porous structure metal material prepared in step S2 to 400-750° C. under vacuum conditions and keeping the temperature for 2-8 hours, then cooling the furnace to room temperature to obtain a porous structure metal material.

[0011] Preferably, step S2 specifically includes the following sub-steps:

[0012] S21: loading the metal hydride powder prepared in step S1 into a powder bin, and selecting a suitable inert gas as a gas source;

[0013] S22: adjusting the distance between the spray gun and the substrate, the movement speed of the spray gun, the heating temperature and pressure of the inert gas, and setting the number of spray layers to 10 to 50;

[0014] S23: starting the device, heating the compressed gas, moving the nozzle and repeating the spraying for 10 to 50 layers according to the same system parameters, the metal hydride powder is cold sprayed on the substrate surface under the acceleration of the inert gas to obtain a hydrogenated porous structure metal material.

[0015] Preferably, the reaction equation for preparing the metal hydride block in step S1 is:

[0016] M+H→MH x

[0017] Wherein, M is the metal block, x is the specific hydrogen content, the metal block is selected from titanium, zirconium, titanium alloy, zirconium alloy or titanium zirconium alloy, the metal block must have metal components that absorb and dehydrogenate hydrogen, and the metal block reaches a specific hydrogen content after the hydrogenation process is completed, that is, the hydrogen content of the metal block is between 0 and the saturated hydrogen content. The control factors of the specific hydrogen content are the first set temperature and the insulation time. If different metal blocks are selected in the hydrogenation process, the first set temperature will be different.

[0018] Preferably, the high-purity H2 atmosphere in step S1 refers to a hydrogen content ≥ 99.999%, the diameters of the stainless steel grinding balls used in the ball milling process are 15 mm, 10 mm and 6 mm respectively, the metal hydride powder is a micron-scale powder, and the size range of the metal hydride powder is 25 to 75 μm.

[0019] Preferably, the inert gas used in the cold spraying process is nitrogen, argon or helium, the content of the inert gas is ≧99.999%, the pressure of the inert gas is 20-50 Bar, and the thickness of every 10 spray layers in the spraying process is 1.1-1.3 mm.

[0020] Preferably, the chemical equation occurring during the dehydrogenation of the hydrogenated metal material in step S2 and step S3 is: MH x →M+H;

[0021] Among them, MH x is a hydrogenated metal material, M is an unhydrogenated metal material, and x is a specific hydrogen content. During the heating process of the dehydrogenation treatment, since the H atmosphere pressure in the environment is 0, H will be removed from TiH x Diffusion out of the matrix to achieve dehydrogenation treatment.

[0022] The second aspect of the present invention provides a porous structure metal material prepared by a preparation method of a honeycomb porous structure metal material based on cold spraying, wherein the metal structure of the porous structure metal material is a honeycomb porous structure, and the porous structure comprises pores, pore walls and triangular nodes, and the pores are formed by connecting adjacent pore walls through triangular nodes, wherein the pore density is 35% to 60%, the pore size is 100 to 3000 μm, the pore wall thickness is 10 to 120 μm, and the pore wall depth is 1 to 5 mm.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] (1) Compared with traditional preparation methods such as casting, powder metallurgy and additive manufacturing, the preparation method of the present invention can realize the rapid, continuous, short-process and low-cost preparation of honeycomb porous structure metal materials, which solves the problems that casting and powder metallurgy are difficult to prepare honeycomb porous structure metal materials and cannot continuously manufacture large-format porous materials.

[0025] (2) Compared with the traditional cold spraying method for preparing metal materials, the in-situ dehydrogenation during the metal hydride cold spraying process will partially remove the oxide layer between the metal particle interfaces, ensuring a better metal bonding effect at the interface of the cold sprayed sample particles, thereby improving the bonding strength between the particles, which is reflected in the improvement of the strength of the metal material in a macroscopic sense. In addition, the application of metal hydride powder effectively avoids the requirements of high critical spraying rate for special powders in cold spraying, greatly broadening the feasibility of cold spraying metal materials.

[0026] (3) The honeycomb porous structure metal material prepared by the preparation method of the present invention uses metal hydride as raw material and is the first honeycomb porous structure metal material prepared based on cold spraying technology. Compared with the metal material processed by conventional cold spraying, it has excellent electromagnetic shielding performance and can be used in the fields of catalysis, radiator, evaporator and sound insulation material at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a cold spraying device for preparing a honeycomb porous structure metal material based on cold spraying according to the present invention;

[0028] Figure 2 This is a scanning electron microscope image of the metal hydride of Ti prepared in Example 1 of the method for preparing a honeycomb porous structure metal material based on cold spraying of the present invention;

[0029] Figure 3 This is a macroscopic photograph of a porous structure metal material prepared in Example 1 of a method for preparing a honeycomb porous structure metal material based on cold spraying of the present invention;

[0030] Figure 4This is a scanning electron microscope image of the top observation hole of the porous structure metal material prepared in Example 1 of the present invention according to a method for preparing a honeycomb porous structure metal material based on cold spraying;

[0031] Figure 5 This is a scanning electron microscope image of the side observation hole of the porous structure metal material prepared in Example 1 of the present invention according to a method for preparing a honeycomb porous structure metal material based on cold spraying;

[0032] Figure 6 This is a sample picture of the metal Ti cold spraying process without hydrogenation treatment in comparative example 1.

[0033] Main reference numerals: inert gas storage device 1; hydrogenated powder silo 2; gas heater 3; sensor 4; nozzle 5; substrate 6. DETAILED DESCRIPTION

[0034] In order to fully describe the technical content, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0035] The present invention provides a method for preparing a honeycomb porous structure metal material based on cold spraying, which specifically comprises the following steps:

[0036] S1. Preparation of metal hydride powder: Place the metal block in an atmosphere furnace, heat the metal block to the first set temperature of 650°C in a high-purity H2 atmosphere at 1 atmosphere and keep it warm for 2 hours, then cool the furnace to room temperature to obtain a metal hydride block. Pour the metal hydride block into the stainless steel grinding tank of the planetary ball mill, and select three stainless steel grinding balls with diameters of 15mm, 10mm and 6mm for ball milling, with a mass ratio of 1:3:1. The ball milling parameters are as follows: the atmosphere is high-purity argon at 1 atmosphere, the ball-to-material ratio is 1 to 2:1, the rotation speed is 400rpm, and the ball milling time is 10min. Then take out the powder and sieve it to obtain a metal hydride powder with a micron particle size.

[0037] Among them, the reaction equation for preparing the metal hydride bulk is:

[0038] M+H→MH x .

[0039] Wherein, M is a metal block, and x is a specific hydrogen content. The metal block may be made of titanium, zirconium, titanium alloy, zirconium alloy, titanium zirconium alloy, etc. The metal block must have metal components that absorb and dehydrogenate hydrogen. Different metal blocks are selected during the hydrogenation process, and the hydrogenation reaction temperature is different. After the hydrogenation process is completed, the metal block reaches a specific hydrogen content, that is, the hydrogen content of the metal block is between 0 and the saturated hydrogen content. For example, the maximum saturated hydrogen content of Ti is 2, and the specific hydrogen content of the hydride TiHx of metal Ti satisfies 0<x≤2. The controlling factors of the specific hydrogen content are mainly the heating temperature and the insulation time.

[0040] S2, cold spray molding: Figure 1 As shown, the cold spray forming equipment is a commercial or self-assembled cold spray system, which includes compressed gas, a gas circuit, a powder supply system, other heating systems, sensors, a nozzle, and a substrate.

[0041] S21: Load the metal hydride powder prepared in step S1 into a powder bin, and select a suitable inert gas as a gas source.

[0042] S22: adjusting the distance between the spray gun and the substrate, the moving speed of the spray gun, the heating temperature and pressure of the inert gas, and setting the number of spray layers to 10 to 50 layers.

[0043] S23: Start the device, heat the compressed gas, move the nozzle and repeat spraying 20 layers according to the same system parameters, cold spray the metal hydride powder on the substrate surface under the acceleration of the inert gas to obtain a hydrogenated porous structure metal material.

[0044] Among them, since the heated compressed gas has a very high movement speed, it will drive the powder in the powder bin to further accelerate to the critical spraying speed through the nozzle and then impact the substrate. During the impact process, the powder undergoes high strain rate deformation and physically and metallurgically bonds with the remaining powder particles to eventually form a deposited block. Cold spray inert gas can be nitrogen, argon or helium as the inert gas in cold spray molding. The cold spray gas pressure is 20 to 50 Bar, and the distance between the spray gun and the substrate is 20 to 40 mm.

[0045] Specifically, during the first layer of cold spraying, the irregular metal hydride powder combines with the substrate to form three structural surfaces: slope, curved surface and plane. During the second layer of cold spraying, the irregular metal hydride powder particle boundaries heat up and dehydrogenate during the deformation process at a high strain rate, resulting in the transformation of the brittle metal hydride powder on the surface into powder particles with a brittle metal hydride phase wrapped inside and a tough metal single substance on the surface. The powder particles are completely broken when impacting the plane surface of the first layer of cold spraying, and it is difficult to form an effective combination with the plane structure. When the powder particles impact the curved surface and the slope structure, the compressive stress of the impact can be decomposed into the component force perpendicular to the slope and the curved surface, thereby promoting the excellent combination of the tough phase of the powder particles with the first layer of cold spraying. In short, the dehydrogenated irregular metal hydride powder has a high deposition efficiency on the slope and curve, but is difficult to deposit on the plane structure. In the subsequent cold spraying process, the particles on the slope and curved surface continue to deposit and increase to form a wall structure, while the plane eventually evolves into a pore structure, and finally forms a honeycomb porous structure metal material.

[0046] S3, dehydrogenation treatment: heating the hydrogenated porous structure metal material prepared in step S2 to 400-750° C. under vacuum conditions and keeping the temperature for 2-8 hours, then cooling the furnace to room temperature to obtain a honeycomb porous structure metal material.

[0047] Specifically, the chemical equation that occurs during the dehydrogenation of hydrogenated metal materials is: MH x →M+H.

[0048] Among them, MH x is a hydrogenated metal material, M is an unhydrogenated metal material, and x is a specific hydrogen content. During the heating process of the dehydrogenation treatment, since the H atmosphere pressure in the environment is 0, H will be removed from TiH x Diffusion out of the matrix to achieve dehydrogenation treatment.

[0049] The following is a further description of a method for preparing a honeycomb porous structure metal material based on titanium hydride powder according to the present invention in combination with an embodiment:

[0050] Embodiment 1:

[0051] A cold spray-based preparation method for a honeycomb porous structure metal material and a preparation method thereof, comprising the following steps:

[0052] The raw materials used in this example are as follows: 99.95wt.% titanium sponge block, hydrogen, nitrogen, and argon.

[0053] S1. Preparation of metal hydride powder: The target component of this embodiment is Ti. First, put 500g of sponge titanium block into an atmosphere furnace, heat the sponge titanium to 650℃ and keep it for 2h in a high-purity H2 atmosphere at 1 atmosphere, then cool the furnace to room temperature to obtain a titanium hydride block. Pour the titanium hydride block into the stainless steel grinding tank of the planetary ball mill. The diameters of the selected stainless steel grinding balls are 15mm, 10mm and 6mm, respectively, and the mass ratio is 1:3:1. The ball milling parameters are as follows: the atmosphere is high-purity argon at 1 atmosphere, the ball-to-material ratio is 1:1, the rotation speed is 400rpm, and the ball milling time is 10min. Then take out the powder and sieve it to obtain titanium hydride powder with a particle size of 45μm.

[0054] The hydrogen content in the titanium hydride powder was tested to be 1.74wt.%, which is lower than the saturated H content in Ti. It can be judged that the powder is TiH. Figure 2 As shown, the TiH powder has an irregular shape.

[0055] S2, cold spraying: Pour the TiH powder prepared in step S1 into the powder bin of the cold spraying system, and use high-purity N2 as the protective gas. The cold spraying parameters are: the distance between the spray gun and the substrate is 30 mm; the spray gun moving speed is 2 mm / s, the compressed N2 heating temperature is 750°C, the compressed N2 pressure is 30 Bar, and the number of spray layers is 20. After cold spraying, a honeycomb porous structure TiH material is obtained.

[0056] S3, dehydrogenation treatment: The hydrogenated porous structure TiH prepared in step S2 is placed in a vacuum sintering furnace, and the furnace is evacuated to 5×10 -3 Pa; then, the temperature was raised to 750°C at a heating rate of 10°C / min and kept at that temperature for 2h; the furnace was cooled to room temperature, and the sample was taken out to obtain a honeycomb porous structure Ti.

[0057] Embodiment 2:

[0058] A cold spray-based preparation method for a honeycomb porous structure metal material and a preparation method thereof, comprising the following steps:

[0059] The raw materials used in this example are as follows: 99.95wt.% zirconium sponge blocks, hydrogen, helium, and argon.

[0060] S1. Preparation of metal hydride powder: The target component of this embodiment is Zr. First, 500g of sponge zirconium block is placed in an atmosphere furnace, and the sponge titanium is heated to 700°C and kept warm for 3 hours in a high-purity H2 atmosphere at 1 atmosphere. Then the furnace is cooled to room temperature to obtain a titanium hydride block. Pour the zirconium hydride block into the stainless steel grinding tank of the planetary ball mill. The diameters of the selected stainless steel grinding balls are 15mm, 10mm and 6mm, respectively, and the mass ratio is 1:3:1. The ball milling parameters are as follows: the atmosphere is 1 atmosphere of high-purity argon, the ball-to-material ratio is 1:1, the rotation speed is 400rpm, and the ball milling time is 10min. Then take out the powder and sieve it to obtain zirconium hydride powder with a particle size of 25μm. After testing, the hydrogen content in the titanium hydride powder is 2.16wt.%, which is ZrH2.

[0061] S2, cold spray molding: Pour the ZrH2 powder prepared in step S1 into the powder bin of the cold spray system, and use high-purity N2 as the protective gas. The cold spray parameters are: the distance between the spray gun and the substrate is 30 mm; the spray gun moving speed is 5 mm / s, the compressed He gas heating temperature is 600°C, the compressed He pressure is 20 Bar, and the number of spray layers is 50. After cold spraying, a honeycomb porous structure ZrH material is obtained.

[0062] S3, dehydrogenation treatment: The hydrogenated porous structure ZrH prepared in step S2 is placed in a vacuum sintering furnace, and the furnace is evacuated to 5×10 -3 Pa; then, the temperature was raised to 400°C at a heating rate of 10°C / min and kept at that temperature for 8h; the furnace was cooled to room temperature, and the sample was taken out to obtain a honeycomb porous structure Zr.

[0063] Embodiment 3:

[0064] A cold spray-based preparation method for a honeycomb porous structure metal material and a preparation method thereof, comprising the following steps:

[0065] The raw materials used in this example are as follows: 99.95wt.% Ti-6Al-4V bulk, hydrogen, nitrogen, and argon.

[0066] S1. Preparation of metal hydride powder: The target component of this embodiment is Ti-6Al-4V. First, put 500g of Ti-6Al-4V block into an atmosphere furnace, heat the alloy to 650℃ and keep it warm for 4h in a high-purity H2 atmosphere at 1 atmosphere, and then cool the furnace to room temperature to obtain a hydrogenated Ti-6Al-4V block. Pour the hydrogenated Ti-6Al-4V block into the stainless steel grinding tank of the planetary ball mill. The diameters of the selected stainless steel grinding balls are 15mm, 10mm and 6mm, respectively, and the mass ratio is 1:3:1. The ball milling parameters are as follows: the atmosphere is 1 atmosphere of high-purity argon, the ball-to-material ratio is 1:1, the rotation speed is 400rpm, and the ball milling time is 20min. Then take out the powder and sieve to obtain zirconium hydride powder with a particle size of 75μm. After testing, the hydrogen content in the titanium hydride powder is 1.18wt.%, which is Ti-6Al-4V-1.18H.

[0067] S2, cold spraying: Pour the Ti-6Al-4V-1.18H powder prepared in step S1 into the powder bin of the cold spraying system, and use high-purity N2 as the protective gas. The cold spraying parameters are: the distance between the spray gun and the substrate is 30 mm; the spray gun moving speed is 1 mm / s, the compressed He gas heating temperature is 1000°C, the compressed N2 pressure is 50 Bar, and the number of spray layers is 30. After cold spraying, a honeycomb porous structure Ti-6Al-4V-1.18H material is obtained.

[0068] S3, dehydrogenation treatment: The hydrogenated porous structure Ti-6Al-4V-1.18H prepared in step S2 is placed in a vacuum sintering furnace, and the furnace is evacuated to 5×10 -3 Pa; then, the temperature was raised to 600°C at a heating rate of 10°C / min and kept at that temperature for 4h; the furnace was cooled to room temperature, and the sample was taken out to obtain a honeycomb porous structure Zr.

[0069] Embodiment 4:

[0070] A cold spray-based preparation method for a honeycomb porous structure metal material and a preparation method thereof, comprising the following steps:

[0071] The raw materials used in this example are as follows: 99.95wt.% Ti-5Al-3V-47Zr blocks, hydrogen, nitrogen, and argon.

[0072] S1. Preparation of metal hydride powder: The target component of this embodiment is: Ti-5Al-3V-47Zr. First, put 500g of Ti-5Al-3V-47Zr block into an atmosphere furnace, heat the alloy to 650℃ and keep it warm for 2h in a high-purity H2 atmosphere at 1 atmosphere, and then cool the furnace to room temperature to obtain a titanium hydride block. Pour the titanium hydride block into the stainless steel grinding tank of the planetary ball mill. The diameters of the selected stainless steel grinding balls are 15mm, 10mm and 6mm, respectively, and the mass ratio is 1:3:1. The ball milling parameters are as follows: the atmosphere is 1 atmosphere of high-purity argon, the ball-to-material ratio is 1:1, the rotation speed is 400rpm, and the ball milling time is 10min. Then take out the powder and sieve to obtain titanium hydride powder with a particle size of 75μm. After testing, the hydrogen content in the titanium hydride powder is 1.54wt.%, which is Ti-5Al-3V-47Zr-1.54H.

[0073] S2, cold spraying: Pour the Ti-5Al-3V-47Zr-1.54H powder prepared in step S1 into the powder bin of the cold spraying system, and use high-purity N2 as the protective gas. The cold spraying parameters are: the distance between the spray gun and the substrate is 30mm; the spray gun moving speed is 2mm / s, the compressed N2 heating temperature is 750℃, the compressed N2 pressure is 30Bar, and the number of spray layers is 20. After cold spraying, a honeycomb porous structure Ti-5Al-3V-47Zr-1.54H material is obtained.

[0074] S3, dehydrogenation treatment: The hydrogenated porous structure Ti-5Al-3V-47Zr-1.54H prepared in step S2 is placed in a vacuum sintering furnace, and the furnace is evacuated to 5×10 -3 Pa; then, the temperature was raised to 750°C at a heating rate of 10°C / min and kept at that temperature for 2h; the furnace was cooled to room temperature, and the sample was taken out to obtain a honeycomb porous structure Ti-5Al-3V-47Zr.

[0075] Comparative Example 1:

[0076] The raw materials used in this comparative example are as follows: 45 μm, 99.95 wt. % Ti powder, and nitrogen.

[0077] Pour Ti powder into the powder bin of the cold spray system, and use high-purity N2 as the protective gas. The cold spray parameters are: the distance between the spray gun and the substrate is 30 mm; the spray gun movement speed is 2 mm / s, the compressed N2 heating temperature is 750 ° C, the compressed N2 pressure is 30 Bar, and the number of spray layers is 20. After cold spraying, the Ti coating is obtained.

[0078] The honeycomb porous structure Ti sample prepared in Example 1 is as follows Figure 3-Figure 5 As shown. The macroscopic dimensions of the porous structure are 65 mm long and 25 mm wide. Figure 4As shown in the figure, a is a honeycomb hole, b is a hole wall, and c is a honeycomb node. When viewed from the top, the porous Ti presents a honeycomb structure, which includes three parts: holes, hole walls, and triangular nodes. According to the area method test, the hole density is about 51%, the average hole diameter is 1200μm, and the hole wall thickness is 56μm. Figure 5 As shown, a is the hole wall, b is the substrate, and the maximum depth is 2.4 mm. The hole is formed by connecting adjacent hole walls at triangular nodes. The compressive fracture strength of the sample is 5.2 MPa and the density is 1.34 g / cm 3 The sample was cut into a ring with an inner diameter of 3.04mm, an outer diameter of 7mm and a thickness of 1.5mm, and then placed in a vector network analyzer for electromagnetic shielding performance testing. The test results showed that the honeycomb porous structure Ti has a shielding effect in the range of 0-1000MHz, with the increase of electromagnetic wave frequency, the sample shielding effect decreases from 100dB to 38dB. After exceeding 1000MHz, the sample shielding effect is about 45dB.

[0079] The macroscopic size of the honeycomb porous structure Zr prepared in Example 2 is 65 mm long and 25 mm wide. Observed from the top, the porous Zr presents a honeycomb structure, which includes three parts: pores, pore walls and triangular nodes. According to the area method test, the pore density is about 45%, the average pore diameter is 600 μm, the pore wall thickness is 10 μm, and the pore wall depth is 5 mm. The pores are formed by connecting adjacent pore walls at the triangular nodes. The compressive fracture strength of the sample is 7.6 MPa. Due to the excellent biocompatibility of Zr, the method of the present invention can process a honeycomb porous structure Zr coating on the surface of a medical alloy, which is beneficial to cell adsorption and cell growth.

[0080] The macroscopic size of the honeycomb porous structure Ti prepared in Example 3 is 65 mm long and 25 mm wide. Observed from the top, the porous Ti-6Al-4V presents a honeycomb structure, which includes three parts: pores, pore walls and triangular nodes. According to the area method test, the pore density is about 35%, the average pore diameter is 100 μm, the pore wall thickness is 80 μm, and the pore wall depth is 3 mm. The pores are formed by connecting adjacent pore walls at the triangular nodes. After testing, the compressive fracture strength of the sample is 8.4 MPa.

[0081] The macroscopic size of the honeycomb porous structure Ti prepared in Example 4 is 65 mm long and 25 mm wide. Observed from the top, the porous Ti presents a honeycomb structure, which includes three parts: pores, pore walls and triangular nodes. According to the area method test, the pore density is about 60%, the average pore diameter is 3000 μm, the pore wall thickness is 56 μm, and the pore wall depth is 1.8 mm. The pores are formed by connecting adjacent pore walls at the triangular nodes. After testing, the compressive fracture strength of the sample is 6.9 MPa.

[0082] like Figure 6As shown in the figure, the macroscopic image of the cold sprayed Ti obtained in the comparative example, wherein the length L is 65 mm and the width is 25 mm. After testing, the cold sprayed Ti is solid and has no honeycomb porous structure. The density of the solid Ti block is 4.48 g / cm 3 The electromagnetic shielding performance test shows that the electromagnetic shielding effect of the solid Ti is 15 dB, which is worse than that of the honeycomb porous structure Ti prepared in Example 1.

[0083] The present invention is based on cold-sprayed honeycomb structure metal materials, and is different from internal through-hole porous materials prepared by casting and powder metallurgy methods. In addition, compared with the selective laser melting method, the method of the present invention has a simple process, no gas protection requirements, and can continuously manufacture large-format porous materials. It can be used in catalysis, radiators, evaporators, sound insulation materials, biomedicine, lightweight structural materials and other fields at low cost. In addition, due to the high degree of freedom of cold spray processing, it can be used to spray a specific thickness of metal material with a porous structure on the surface of biological plant parts, thereby facilitating cell adhesion and value-added.

[0084] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a honeycomb porous structure metal material based on cold spraying, characterized in that: The preparation method comprises the following steps: S1. Prepare metal hydride powder, specifically: S11, placing a metal block in an atmosphere furnace, heating the metal block to a first set temperature in a high-purity H2 atmosphere at 1 atmosphere pressure, keeping the temperature for 2 to 3 hours, and then cooling the furnace to room temperature to obtain a metal hydride block; S12, pouring the metal hydride block into a planetary ball mill and ball milling according to preset ball milling parameters, taking out the ball milled powder and sieving it to obtain metal hydride powder with a micron particle size; the ball milling parameters include: the ball milling atmosphere is 1 atmosphere of high-purity argon gas, the ball-to-material ratio is 1 to 2:1, the rotation speed is 400 to 500 rpm, and the ball milling time is 10 to 15 minutes; S2, cold spray molding: the metal hydride powder prepared in S1 is combined with a substrate under inert gas acceleration to form surfaces with three structures: slope, curved and plane. During the continuous cold spraying process, the boundary of the metal hydride powder heats up and undergoes dehydrogenation during the deformation process at a high strain rate, forming powder particles with surface toughness. When the powder particles impact the curved surface and the slope structure, the tough phase of the powder particles has a high deposition efficiency on the slope and curved surface, but is difficult to deposit on the plane. After subsequent repeated cold spraying processes, the surface of the slope structure and the curved surface structure is continuously deposited and increased to form a wall structure, and the surface of the plane structure forms a pore structure, finally forming a hydrogenated porous structure metal material; S3, dehydrogenation treatment: heating the hydrogenated porous structure metal material prepared in step S2 to 400-750° C. under vacuum conditions and keeping the temperature for 2-8 hours, then cooling the material to room temperature in a furnace to obtain a porous structure metal material.

2. The method for preparing a honeycomb porous structure metal material based on cold spraying according to claim 1, characterized in that: Step S2 specifically includes the following sub-steps: S21: loading the metal hydride powder prepared in step S1 into a powder bin, and selecting a suitable inert gas as a gas source; S22: adjusting the distance between the spray gun and the substrate, the moving speed of the spray gun, the heating temperature and pressure of the inert gas, and setting the number of spray layers to 10 to 50; S23: starting the device, heating the compressed gas, moving the nozzle and repeating the spraying for 10 to 50 layers according to the same system parameters, the metal hydride powder is cold sprayed on the substrate surface under the acceleration of the inert gas to obtain a hydrogenated porous structure metal material.

3. The method for preparing a honeycomb porous structure metal material based on cold spraying according to claim 1, characterized in that: The reaction equation for preparing the metal hydride block in step S1 is: M+H→MH x Wherein, M is the metal block, x is the specific hydrogen content, the metal block is selected from titanium, zirconium, titanium alloy, zirconium alloy or titanium zirconium alloy, the metal block must have metal components that absorb and dehydrogenate hydrogen, and the metal block reaches a specific hydrogen content after the hydrogenation process is completed, that is, the hydrogen content of the metal block is between 0 and the saturated hydrogen content. The control factors of the specific hydrogen content are the first set temperature and the insulation time. If different metal blocks are selected in the hydrogenation process, the first set temperature will be different.

4. The method for preparing a honeycomb porous structure metal material based on cold spraying according to claim 1, characterized in that: The high-purity H2 atmosphere in step S1 refers to a hydrogen content of ≥99.999%. The diameters of the stainless steel grinding balls used in the ball milling process are 15 mm, 10 mm and 6 mm respectively. The metal hydride powder is a micron-scale powder, and the size range of the metal hydride powder is 25 to 75 μm.

5. The method for preparing a honeycomb porous structure metal material based on cold spraying according to claim 1 or 2, characterized in that: The inert gas used in the cold spraying process is nitrogen, argon or helium, the content of the inert gas is ≧99.999%, the pressure of the inert gas is 20-50 Bar, and the thickness of every 10 spray layers in the spraying process is 1.1-1.3 mm.

6. The method for preparing a honeycomb porous structure metal material based on cold spraying according to claim 1, characterized in that: The chemical equation occurring during the dehydrogenation of the hydrogenated metal material in step S2 and step S3 is: MH x →M+H; Among them, MH x is a hydrogenated metal material, M is an unhydrogenated metal material, and x is a specific hydrogen content. During the heating process of the dehydrogenation treatment, since the H atmosphere pressure in the environment is 0, H will be removed from MH x Diffusion out of the matrix to achieve dehydrogenation treatment.

7. A porous metal material prepared by the method for preparing a honeycomb porous metal material based on cold spraying according to any one of claims 1 to 6, characterized in that: The metal structure of the porous metal material is a honeycomb porous structure, which includes holes, hole walls and triangular nodes. The holes are formed by connecting adjacent hole walls through triangular nodes, wherein the hole density is 35% to 60%, the hole size is 100 to 3000 μm, the hole wall thickness is 10 to 120 μm, and the hole wall depth is 1 to 5 mm.

Images