A composite nickel-based alloy microchannel and a preparation method thereof

Abstract

The application provides a composite nickel-based alloy microchannel and a preparation method thereof, and the preparation method comprises the following steps: S1, preparing a nickel-based alloy powder comprising the following element components in percentage by mass: Cr: 15-20%, Mo: 16-20%, Mn: 0.5-1%, W: 2-3%, and Ni: 54-62.5%, and the nickel-based alloy powder is used; S2, adding 2-3% silicon powder into the nickel-based alloy powder in S1, and ball-milling the mixture, wherein no grinding ball is added during the ball-milling process, so as to obtain a nickel-based alloy composite powder, and the nickel-based alloy composite powder is used; S3, preheating, using 3D printing to prepare a target from the nickel-based alloy composite powder in S2, and performing annealing treatment at 600-780 DEG C, and cooling in the furnace, so that the composite nickel-based alloy microchannel is obtained. The composite nickel-based alloy microchannel prepared by selecting elements and separately adding silicon powder has excellent 3D printing forming quality, no crack, high density, few pores, high density, good corrosion resistance and good forming quality, and can effectively avoid the problems of poor corrosion resistance and poor forming quality of the prior art and materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal additive manufacturing, in particular to a composite nickel-based alloy microchannel and a preparation method thereof. BACKGROUND

[0002] Microchannels, also known as microchannel reactors, are three-dimensional structural units manufactured from solid substrates for chemical reactions. The fluid channel equivalent diameter of such a reactor is only a few microns or a few hundred microns, and it contains numerous microchannels. The dynamic boundary layer thickness is greatly reduced, and the average heat and mass diffusion distance is greatly shortened, so that the fluid in the microchannel can flow in a specific physical state in the reactor, enabling efficient mass and heat transfer between fluids, utilizing the inherent characteristics of fast surface reaction kinetics to achieve process intensification of chemical reactions, and greatly improving reaction rates.

[0003] In the manufacturing technology of metal microchannel reactors, the traditional manufacturing method is to first use mechanical processing, and then bolt compression or diffusion welding to obtain a shaped microchannel. However, there are too many welding surfaces, the pressure-bearing capacity is poor, and the risk of leakage is great. In 2019, Chinese patent CN110935407A “Microchannel reactor and manufacturing method thereof” first manufactured a 3D printed microchannel with a large holdup liquid. Its special forming method is different from traditional processing methods, has the advantages of one-piece forming, high space utilization, high density, and low cost, and can manufacture structures that are difficult to manufacture by traditional processing methods. 3D printed microchannels are revolutionary replacement technologies that can replace traditional chemical equipment due to their safety, high efficiency, and green energy saving.

[0004] However, due to the high specific surface area and small channel characteristic size of microchannels, even extremely small corrosion degradation has a very significant impact on microchannels, which makes microchannels have high corrosion resistance requirements for materials. Currently, the raw materials used in 3D printed microchannels are mainly pure tantalum, nickel-based superalloys, hastelloy, and stainless steel. Ordinary nickel-based alloys or stainless steel cannot withstand strong acid corrosion environments such as hydrofluoric acid for a long time, while pure tantalum, which can withstand corrosion, is very expensive and cannot be used to produce microchannel reactors entirely. Although hastelloy has good corrosion resistance, it cannot maintain stability under long-term acidic liquid scouring, especially in environments exceeding 50°C. As the core component of microreactors, a material with higher corrosion resistance needs to be developed.

[0005] Chinese patent CN117643849A “Microchannel reactor and manufacturing method thereof” discloses a 3D printed microchannel made of a double-metal material in an ABA sandwich structure. Only the middle interlayer structure uses high-corrosion-resistant B material to reduce the overall cost of the microchannel reactor, but this patent does not study the corrosion resistance of the microchannel material.

[0006] Therefore, it is of great significance to develop a composite nickel-based alloy microchannel that is uniformly formed and can improve the comprehensive performance of the composite nickel-based alloy microchannel, as well as a preparation method and application thereof. Summary of the Invention

[0007] Given that the corrosion resistance of existing 3D-printed microchannels still needs to be further improved, the present invention provides a composite nickel-based alloy microchannel and its preparation method. By doping with silicon powder to introduce partial covalent bonds, and then using heat treatment to evenly diffuse the silicon throughout the metal, the corrosion resistance of the microchannel is comprehensively enhanced. The resulting composite nickel-based alloy microchannel exhibits excellent 3D printing performance, is crack-free, has high density, and exhibits minimal pores. This demonstrates high density, excellent corrosion resistance, and superior build quality, effectively avoiding the poor corrosion resistance and build quality associated with existing technologies and materials.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0010] S1. Prepare nickel-based alloy powder comprising the following elements by mass percentage: Cr: 15-20%, Mo: 16-20%, Mn: 0.5-1%, W: 2-3%, Ni: 54-62.5% for use;

[0011] S2 to the nickel-based alloy powder S1 doped with 2-3% silicon powder, ball milling mixing, the ball milling process is not added to obtain a nickel-based alloy composite powder, set aside;

[0012] S3 preheating, using 3D printing to prepare the nickel-based alloy composite powder S2 target, annealing at 600-780 ° C, and furnace cooling to obtain the composite nickel-based alloy microchannel;

[0013] The nickel-based alloy powder described in S1 has a particle size of 15-53 μm and a sphericity of ≥90%, and the silicon powder described in S2 has a particle size of 5-15 μm and a sphericity of ≥80%;

[0014] The 3D printing laser power of S3 is 250-450w, the speed is 600-1000mm / s, and the powder thickness is 40-60μm.

[0015] Existing corroded chemical transportation pipeline materials make it difficult to maintain long-term safe transportation. Therefore, the pipelines are replaced with new materials during annual maintenance. However, microchannels, as core components of key chemical equipment, are difficult to meet the annual replacement requirements due to issues such as value and materials. The failure of microchannels is often caused by microscopic pitting, and pitting often occurs first in the grain boundaries.

[0016] In view of this, the present application creatively proposes a method for preparing a composite nickel-based alloy microchannel, by compounding silicon powder and nickel-based alloy powder according to the ratio provided in the present application, 3D printing is used to prepare the composite nickel-based alloy microchannel, partial covalent bonds are introduced by doping silicon powder, and the silicon element is evenly diffused throughout the metal through heat treatment. During the 3D printing process, the nickel-based alloy powder melts and solidifies, and the boundaries of the general nickel-based alloy powder melt to form a eutectic structure with the silicon powder, existing in the form of a mixture, thereby comprehensively enhancing the corrosion resistance of the composite nickel-based alloy microchannel, reducing the stress of the composite nickel-based alloy microchannel, and preventing cracks.

[0017] When the silicon powder content exceeds 3%, cracks are prone to appear in the composite nickel-based alloy microchannel. When the content exceeds 5%, cracks will inevitably appear in the 3D printed sample. The reason is that excessive silicon powder can easily break the balance of the alloy elements, causing the FCC phase in the composite nickel-based alloy microchannel to transform into the BCC phase, and unmelted silicon particles will appear, which will lead to cracks.

[0018] In this application, by preferably selecting a nickel-based alloy powder particle size of 15-53 μm and a sphericity of ≥90%, and preferably selecting a silicon powder particle size of 5-15 μm and a sphericity of ≥80%, it is ensured that the silicon powder is effectively retained in the gaps of the nickel-based alloy powder by ball milling, so that the silicon powder and the nickel-based alloy powder are fully mixed, thereby avoiding the situation in which silicon powder segregation during 3D printing causes defects in the composite nickel-based alloy microchannel, ensuring the formation of a good eutectic structure, and improving the molding quality of the composite nickel-based alloy microchannel. If the silicon powder particle size is too small or the nickel-based alloy powder particle size is too large, the silicon powder will not be able to be well mixed with the nickel-based alloy powder, and silicon powder segregation may occur during the printing process. Similarly, if the silicon powder particle size is too large or the nickel-based alloy powder particle size is too small, it will be difficult to form a good eutectic structure, affecting the molding quality.

[0019] In this application, it is preferred not to add any grinding balls during the ball milling process. If grinding balls are added, the mixed silicon powder may be broken into nanopowders, which may cause the silicon powder particle size to be unable to be well matched with the nickel-based alloy powder, resulting in defects in the composite nickel-based alloy microchannels.

[0020] In this application, the preferred 3D printing laser power is 250-450w, the speed is 600-1000mm / s, and the powder thickness is 40-60μm. If the laser power is less than 250w, the laser energy input is low, and the powder melting is not complete. If the laser power exceeds 450w, it is easy to cause element burnout; the scanning speed is lower than 600mm / s, the energy input time is long, and voids are prone to occur. The scanning speed is higher than 1000mm / s, the energy input time is short, and the powder is prone to unmelted phenomenon; if the powder thickness is lower than 40μm, powder jamming is easy to occur, and the powder cannot be evenly spread. If the powder spraying thickness is higher than 60 microns, the powder is prone to sintering.

[0021] In this application, it is preferred that 3D printing also include an annealing step immediately after printing is completed. Annealing can better promote the solid solution of the metal, increase the corrosion resistance of the metal, eliminate stress, and reduce the chance of cracking. If the annealing temperature is lower than 600°C, it is easy to cause the solid solution of silicon element to be unclear and the corrosion resistance to be improved. If it is higher than 780°C, it is easy to cause changes in the coating structure and performance.

[0022] Furthermore, the nickel-based alloy powder described in S1 has a median particle size of 30-35 μm and a fluidity of 15-20 s / 50 g.

[0023] Furthermore, the nickel-based alloy powder described in S1 is prepared by the following preparation method:

[0024] The required metal elements are mixed in proportion, placed in a smelting furnace, and repeatedly smelted and stirred three times in a vacuum to obtain a nickel-based alloy ingot, which is then powdered by gas atomization to obtain the nickel-based alloy powder.

[0025] Furthermore, the purity of the metal element is greater than 99.7%, and the particle size is 0.5-3 mm.

[0026] Furthermore, the median particle size of the silicon powder in S2 is about 8-10 μm.

[0027] Furthermore, the ball milling mixing time in S2 is 60-180 min.

[0028] Furthermore, the 3D printing in S3 is to deposit the nickel-based alloy composite powder on the steel plate using a 3D printing method.

[0029] Furthermore, the steel plate is made of 45 steel.

[0030] Furthermore, the preheating temperature in S3 is 200-300°C.

[0031] Furthermore, the annealing treatment in S3 is carried out at 600-780° C. for 60-240 minutes.

[0032] Another object of the present invention is to provide a composite nickel-based alloy microchannel.

[0033] A composite nickel-based alloy microchannel is prepared by any of the aforementioned composite nickel-based alloy microchannel preparation methods.

[0034] Furthermore, the microchannel has an FCC phase.

[0035] Furthermore, the microchannel has an elliptical series structure.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] The present application is to obtain a composite nickel-based alloy microchannel by compounding a nickel-based alloy with a silicon element, wherein the added Cr, Mo, and Si can effectively improve the acid corrosion resistance of the nickel-based alloy, wherein Cr and Mo can significantly improve the acid corrosion of Ni, the solid solution nature of Si, and it has a strong interatomic bonding force with the alloy, with the characteristics of coexistence of covalent bonds and metallic bonds. The main role of Si and W is to improve the hardness and strength of the alloy, wherein Si, in addition to increasing corrosion resistance, also has the effect of increasing hardness, while W can reduce the elongation of the alloy to a small extent, improve the strength limit and yield point of the alloy, and can also improve the hardness and wear resistance of the alloy. In addition to the above gain effect, Cr, Mo, and Mn are similar to the atomic diameter of Ni, effectively promoting lattice distortion, and can alleviate the brittleness problem caused by Si and W.

[0038] The present application dopes silicon into the composite nickel-based alloy microchannel by doping silicon powder alone, avoiding the problem of cracks that cannot be solved by heating during the printing process due to the large stress when silicon is doped with nickel-based alloy powder in the form of an alloy, and the forming quality of the composite nickel-based alloy microchannel cannot be guaranteed. By doping small-particle silicon powder alone, the silicon powder is distributed in the gaps of the nickel-based alloy powder during the printing process, so that the silicon element is dissolved into the grains as little as possible during the printing process, and most of it remains in the grain boundaries in the form of eutectic, reducing the generation of cracks. Subsequently, the silicon element is evenly diffused throughout the entire composite nickel-based alloy microchannel through heat treatment, thereby comprehensively enhancing the corrosion resistance and obtaining a composite nickel-based alloy microchannel with excellent forming quality and good corrosion resistance.

[0039] The composite nickel-based alloy microchannel provided in this application has excellent 3D printing molding quality, no cracks, high density, and few pores, which can effectively avoid the problems of cracks and pores caused by printing quality. At the same time, heat treatment makes the distribution of various elements more uniform, effectively avoiding the problem of pitting corrosion, and the corrosion resistance is further improved. It can be used in microreactor equipment in acidic corrosive environments and has broad economic value in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The invention is further described with reference to the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the invention. A person skilled in the art can obtain other drawings based on the following drawings without making any creative effort.

[0041] Figure 1 This is a microstructure diagram of the composite nickel-based alloy microchannel in Example 1 of the present application.

[0042] Figure 2 This is a macroscopic image of a composite nickel-based alloy sample prepared by the method for preparing a composite nickel-based alloy microchannel of the present application.

[0043] Figure 3 This is a microstructure diagram of the composite nickel-based alloy microchannel in Example 1 of the present application after being immersed in a mixed acid for 60 days.

[0044] Figure 4 This is a picture of the composite nickel-based alloy microchannel sample of Example 1 of this application. DETAILED DESCRIPTION

[0045] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention is further described by the following examples. Obviously, the following examples are only a part of the embodiments of the present invention, rather than all the embodiments; it should be understood that the embodiments of the present invention are only used to illustrate the technical effects of the present invention, and are not used to limit the scope of protection of the present invention.

[0046] The raw materials in the examples can be obtained commercially; unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0047] Example 1

[0048] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0049] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0050] S2. The nickel-based alloy powder described in S1 was doped with 2% silicon powder and placed in a planetary ball mill. The mixture was ball-milled for 80 min without adding grinding balls during the ball milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0051] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 400W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 700°C for 120min, and then cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0052] Example 2

[0053] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0054] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0055] S2. The nickel-based alloy powder of S1 was doped with 3% silicon powder and placed in a planetary ball mill. The mixture was milled for 80 min without adding grinding balls during the milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0056] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 400W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 700°C for 120min, and then cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0057] Compared with Example 1, the main difference of this embodiment is that the doping amount of silicon powder in step S2 is 3%.

[0058] Example 3

[0059] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0060] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0061] S2. The nickel-based alloy powder described in S1 was doped with 2.5% silicon powder and placed in a planetary ball mill. The mixture was milled for 80 min without adding grinding balls during the milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0062] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 400W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 700°C for 120min, and then cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0063] Compared with Example 1, the main difference of this embodiment is that the doping amount of silicon powder in step S2 is 2.5%.

[0064] Example 4

[0065] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0066] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0067] S2. The nickel-based alloy powder described in S1 was doped with 2% silicon powder and placed in a planetary ball mill. The mixture was ball-milled for 80 min without adding grinding balls during the ball milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0068] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 450W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 700°C for 120min, and cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0069] Compared with Example 1, the main difference of this embodiment is that the laser power in step S3 is 450W.

[0070] Example 5

[0071] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0072] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0073] S2. The nickel-based alloy powder described in S1 was doped with 2% silicon powder and placed in a planetary ball mill. The mixture was ball-milled for 80 min without adding grinding balls during the ball milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0074] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 500W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 700°C for 120min, and cooled with the furnace to obtain the composite nickel-based alloy microchannel.

[0075] Compared with Example 1, the main difference of this embodiment is that the laser power in step S3 is 500W.

[0076] Example 6

[0077] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0078] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0079] S2. The nickel-based alloy powder described in S1 was doped with 2% silicon powder and placed in a planetary ball mill. The mixture was ball-milled for 80 min without adding grinding balls during the ball milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0080] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 400W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 750°C for 150min, and then cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0081] Compared with Example 1, the main difference of this embodiment is that the annealing treatment in step S3 is carried out at 750° C. for 150 minutes.

[0082] Example 7

[0083] A method for preparing a composite nickel-based alloy microchannel comprises the following steps:

[0084] S1. Prepare nickel-based alloy powder comprising the following elements, by mass percentage: 15% Cr, 20% Mo, 0.5% Mn, 2% W, and 62.5% Ni, for later use. The nickel-based alloy powder has a sphericity of ≥90%, a particle size distribution of 20-50 μm, a median particle size of 30-35 μm, and a flowability of 17 s / 50 g.

[0085] S2. The nickel-based alloy powder described in S1 was doped with 2% silicon powder and placed in a planetary ball mill. The mixture was ball-milled for 80 min without adding grinding balls during the ball milling process to obtain a nickel-based alloy composite powder for later use. The sphericity of the silicon powder was ≥80%, the particle size distribution was 5-15 μm, the median particle size was 8-10 μm, and the flowability was 25 s / 50 g.

[0086] S3. Place the No. 45 steel plate in the forming chamber, polish the surface of the steel plate, and wipe it clean with alcohol; add the mixed nickel-based alloy composite powder into the powder chamber, preheat it to 240°C, and use 3D printing to prepare the nickel-based alloy composite powder described in S2 to obtain the target. The process parameters of 3D printing are as follows: laser power of 400W, scanning speed of 850mm / s, powder thickness of 50μm, and after 3D printing, annealing treatment is carried out simultaneously at 780°C for 150min, and then cooled in the furnace to obtain the composite nickel-based alloy microchannel.

[0087] Compared with Example 1, the main difference of this embodiment is that the annealing treatment in step S3 is carried out at 780° C. for 150 minutes.

[0088] Comparative Example 1

[0089] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0090] Compared with Example 1, the doping amount of silicon powder in step S2 of this comparative example is 5%.

[0091] Comparative Example 2

[0092] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0093] Compared with Example 1, the doping amount of silicon powder in step S2 of this comparative example is 6%.

[0094] Comparative Example 3

[0095] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0096] Compared with Example 1, the particle size of the silicon powder in step S2 of this comparative example is 15-53 μm, and the sphericity is less than 80%.

[0097] Comparative Example 4

[0098] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0099] Compared with Example 1, the particle size of the silicon powder in step S2 of this comparative example is 15-53 μm, and the sphericity is less than 60%.

[0100] Comparative Example 5

[0101] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0102] Compared with Example 1, grinding balls were added during the ball milling process in step S2 of this comparative example.

[0103] Comparative Example 6

[0104] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0105] Compared with Example 1, the 3D printing scanning speed in step S3 of this comparative example is 500 mm / s.

[0106] Comparative Example 7

[0107] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0108] Compared with Example 1, the 3D printing scanning speed in step S3 of this comparative example is 1200 mm / s.

[0109] Comparative Example 8

[0110] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0111] Compared with Example 1, no annealing treatment is performed in step S3 of this comparative example.

[0112] Comparative Example 9

[0113] A method for preparing a composite nickel-based alloy microchannel, wherein the steps not specifically described are the same as those in Example 1, except that:

[0114] Compared with Example 1, step S3 of this comparative example does not perform furnace cooling.

[0115] The composite nickel-based alloy microchannel of Example 1 was characterized and analyzed, and the results are shown below:

[0116] The microstructure of the composite nickel-based alloy microchannel obtained in this embodiment is shown in FIG. Figure 1 As shown. Figure 1 It can be seen that the composite nickel-based alloy microchannel obtained in this embodiment is well-formed, relatively flat, crack-free, and dense with a density of 99.9% and no unmelted particles.

[0117] like Figure 2 As shown, the composite nickel-based alloy sample prepared by the method for preparing the composite nickel-based alloy microchannel of the present application has a good macroscopic shape, a relatively smooth surface and no cracks.

[0118] like Figure 3 As shown, the microstructure of the composite nickel-based alloy microchannel obtained in this embodiment was immersed in a mixed solution of nitric acid and sulfuric acid at 50° C. for 90 days, and the corrosion resistance was 0.0143 mm / a. The corrosion resistance of the sample was better than that of the Hastelloy material.

[0119] like Figure 4 As shown, the composite nickel-based alloy microchannel sample obtained in this embodiment has excellent forming quality, a smooth surface, and no cracks.

[0120] The test results of the other embodiments are basically consistent with the above, as shown in Table 1 below:

[0121] Table 1 Test data of composite nickel-based alloy microchannels in Examples 2-7

[0122]

[0123] The performance tests of Comparative Examples 1-9 were performed using the same testing method as Example 1.

[0124] The results are shown in Table 2 below:

[0125] Table 2 Comparative Examples 1-9 Composite Nickel-Based Alloy Microchannel Performance Test Results

[0126]

[0127]

[0128] As can be seen from the table above, the embodiments of the present invention have high density, good corrosion resistance, and good molding quality, without deformation or cracks, and can effectively avoid the problems of poor corrosion resistance and poor molding quality of existing technologies and materials. However, in Comparative Examples 1 and 2, the silicon powder doping amount exceeds the range, breaking the balance of the alloy elements and generating cracks; in Comparative Example 3, the silicon powder particle size is too large, making it difficult to form a good eutectic structure, resulting in poor molding quality; in Comparative Example 4, the silicon powder particle size is too large and the sphericity is too small, resulting in poor molding quality; in Comparative Example 5, grinding balls are added during the ball milling process, causing the mixed silicon powder to break into nanopowder and fail to form; in Comparative Examples 6 and 7, the laser parameters exceed the range and there are many surface defects; in Comparative Example 8, no annealing treatment is performed, resulting in high stress and deformation of the surface; in Comparative Example 9, no furnace cooling is performed, resulting in cracks.

[0129] In summary, the present invention obtains a composite nickel-based alloy microchannel by compounding a nickel-based alloy with a silicon element, and improves the hardness and strength of the composite nickel-based alloy microchannel through the synergistic effect of Cr, Mo, Mn, W, Ni and Si elements, effectively improving the acid corrosion resistance of the nickel-based alloy. The silicon element is doped into the composite nickel-based alloy microchannel by the operation of doping silicon powder alone, so that the silicon element is dissolved into the grain as little as possible during the printing process, and most of it remains in the grain boundary in the form of a eutectic, reducing the generation of cracks. Subsequently, the silicon element is uniformly diffused throughout the composite nickel-based alloy microchannel by heat treatment, thereby comprehensively enhancing the corrosion resistance and obtaining a composite nickel-based alloy microchannel with excellent forming quality and good corrosion resistance. The 3D printing molding quality is excellent, there is no crack, high density, and few pores, which can effectively avoid the problems of cracks and pores caused by printing quality. At the same time, the heat treatment makes the distribution of each element more uniform, effectively avoiding the problem of pitting corrosion, and the corrosion resistance is further improved. It can be used for microreactor equipment in acidic corrosive environments, and has broad economic value in the future.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a composite nickel-based alloy microchannel, characterized in that: The following steps are involved: S1. Prepare nickel-based alloy powder, comprising the following elements by mass percentage: Cr: 15-20%, Mo: 16-20%, Mn: 0.5-1%, W: 2-3%, Ni: 54-62.5%, set aside; S2 to the nickel-based alloy powder S1 doped with 2-3% silicon powder, ball milling mixing, the ball milling process is not added to obtain a nickel-based alloy composite powder, set aside; S3. The mixed nickel-based alloy composite powder was added to the powder bin, preheated, and the nickel-based alloy composite powder was prepared using 3D printing to obtain the target, annealed at 600-780°C, and cooled in the furnace to obtain the composite nickel-based alloy microchannel; The nickel-based alloy powder in S1 has a particle size of 15-53 μm and a sphericity of ≥90%, and the silicon powder in S2 has a particle size of 5-15 μm and a sphericity of ≥80%; The 3D printing laser power of S3 is 250-450w, the speed is 600-1000mm / s, and the powder thickness is 40-60µm.

2. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The nickel-based alloy powder described in S1 has a median particle size of 30-35 μm and a fluidity of 15-20 s / 50 g.

3. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The silicon powder S2 has a median particle size of 8-10 μm and a fluidity of 15-30 s / 50 g.

4. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The ball milling mixing time in S2 is 60-180 min.

5. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The 3D printing described in S3 is to deposit the above nickel-based alloy composite powder on the steel plate using a 3D printing method.

6. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The preheating temperature in S3 is 200-300°C.

7. A method for preparing a composite nickel-based alloy microchannel according to claim 1, characterized in that: The annealing treatment in S3 is carried out at 600-780° C. for 60-240 minutes.

8. A composite nickel-based alloy microchannel, characterized in that: The composite nickel-based alloy microchannel is prepared by the preparation method according to any one of claims 1 to 7.

9. A composite nickel-based alloy microchannel according to claim 8, characterized in that: The microchannel has an FCC phase.

10. A composite nickel-based alloy microchannel according to claim 8, characterized in that: The microchannel has an elliptical series structure.

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