Method for rapidly preparing coating on surface of metal material and product

Abstract

The invention relates to a method for rapidly preparing a coating on the surface of a metal material and a product, and the method comprises the following steps: accurately regulating and controlling parameters such as pulse current, sintering pressure and sintering time required in the process of preparing the coating by flash sintering according to different coating matrixes, coating thicknesses and coating materials required to be prepared; according to the method, wear-resistant steel is used as a coating matrix, the TiC-M2 iron-based composite coating is prepared on the surface, and the remarkable advantages of the flash sintering technology in the aspect of preparing the high-performance coating are verified. Compared with a traditional coating preparation method, the method has the advantages that the required coating can be efficiently prepared on the surface of the metal material, the surface performance of the material is improved, the limitation of a traditional process on coating components and structural design is broken through, and a new way is provided for preparing a high-performance composite coating which is difficult to realize in the past; and the method has important significance for promoting the development of a high-end equipment key component surface strengthening technology.

Description

Technical Field

[0001] This invention belongs to the field of surface coating preparation technology, specifically relating to a method and product for rapidly preparing coatings on the surface of metal materials. Background Technology

[0002] With the rapid development of engineering technology and material performance, and the increasing demand for high-performance materials, adding coatings to the substrate to meet the increasingly higher performance requirements of wear resistance, corrosion resistance, impact resistance and fatigue resistance has made the preparation of material surface coatings a major highlight in the field of material surface treatment.

[0003] Current coating preparation technologies mainly include thermal spraying, physical or chemical deposition, and the mainstream laser cladding technology. However, current coating preparation technologies have drawbacks such as high production costs, long preparation times, generation of toxic gases during the preparation process, large equipment investment, and complex process parameter control. Coatings prepared by laser cladding technology have strong metallurgical bonding and good shape adaptability, and are often used for coating preparation on workpieces with special shapes. However, the problems of high preparation costs and long preparation times are still difficult to solve. The coatings prepared by other coating preparation methods have weak bonding strength with the substrate. At present, there is still no efficient, fast, strong bonding, and simple equipment method for preparing workpiece surface coatings.

[0004] In recent years, pulsed current flash sintering technology has been applied to the rapid preparation of ceramic and metallic materials that are difficult to manufacture. Due to the presence of voids in the powder, the Joule heating introduced by the current rapidly liquefies the low-melting-point powder, filling the voids. The core advantage of flash sintering technology lies in its extremely fast sintering speed (typically on the order of seconds to minutes), which is expected to significantly shorten the entire coating preparation cycle from the traditional tens of minutes to several hours. However, the coating preparation time still requires 20-100 minutes in the existing technology CN117187742A, which discloses a coating and preparation method that does not form a needle-like phase at the interface with a nickel-based alloy, and the density of the prepared material is above 98%. Compared with traditional sintering methods, flash sintering has the characteristics of being more dense, more efficient, and superior integrated sintering, making the technology of rapid material preparation using flash sintering highly anticipated. However, whether this technology can be used to rapidly prepare coatings on the surface of metallic conductors remains to be explored. Summary of the Invention

[0005] In order to overcome the above-mentioned problems in the prior art, the present invention provides a method and product for rapidly preparing a coating on the surface of a metal material, which solves the above-mentioned problems in the prior art.

[0006] A method for rapidly preparing a coating on the surface of a metallic material includes the following steps: S1. Grind and clean the surface of the metal substrate to which the coating is to be prepared; S2. Prepare the raw material powder according to the desired coating; S3. Place the cleaned matrix and the prepared powder into a sintering mold; S4. Flash sintering is performed in a sintering mold to complete the coating preparation on the substrate surface.

[0007] In addition to the aspects and any possible implementations described above, a further implementation is provided in which, in step S1, the substrate surface is successively polished with 400-800 grit, 1000-1400 grit, and 1800-2500 grit sandpaper.

[0008] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the coating is a TiC-M2 iron-based composite material, which is made from two raw material powders: TiC powder and M2 high-speed steel powder. The two powders are mixed by a high-speed ball mill with a rotation speed of 50~500 r / min. After ball milling for 30 min, the direction is reversed, and the direction is reversed again after an interval of 10 min. The ball milling time is 1 h~20 h.

[0009] In addition to the aspects and any possible implementations described above, a further implementation is provided in which, in S3, the sintering mold and the sintering material are separated by a ceramic tube, and the upper side of the raw material powder is separated from the upper tungsten electrode of the sintering mold by graphite paper.

[0010] In addition to the aspects described above and any possible implementation, a further implementation is provided in which the TiC powder has a particle size of 1 μm to 3 μm and the M2 high-speed steel powder has a particle size of 15 to 53 μm.

[0011] In addition to the aspects and any possible implementations described above, a further implementation is provided in which sintering in S4 is performed using a pulsed current, wherein the pulsed current is 0.5kA~5kA, the current frequency is 100~20000Hz, the sintering time is 10s~300s, and the sintering pressure is 0.1t~5t, wherein the pressure is provided by a jack and displayed by a pressure gauge.

[0012] In addition to the aspects and any possible implementations described above, a further implementation is provided, wherein S4 specifically includes: setting pulse current, pressure, and mixed powder quality parameters according to the composition of the prepared coating and the required thickness, specifically as follows: When preparing a TiC-M2 iron-based composite coating with a thickness of (0.5, 1] ​​μm, 5 × 10⁻⁶ mixed powders containing 10%~40% TiC-M2 were used. -3 g / mm 2 ~2.3×10 -2 g / mm 2The flash sintering pulse current is 2.5kA to 3.2kA, the sintering pressure is 1t to 5t, and the sintering time is 10s to 300s. When preparing a TiC-M2 iron-based composite coating with a thickness of (1, 1.5] μm, a mixed powder containing 10%–40% TiC-M2 was used at a density of 1.7 × 10⁻⁶ μm. -2 g / mm 2 ~3.5×10 -2 g / mm 2 The pulse current for flash sintering is 2.7kA to 3.5kA, the sintering pressure is 1t to 5t, and the sintering time is 10s to 300s.

[0013] In addition to the aspects and any possible implementations described above, a further implementation is provided in which the ceramic tube has an inner diameter of 11.8 mm to 12 mm and is crushed after sintering to prevent it from sticking to the sintering mold.

[0014] In addition to the aspects described above and any possible implementations, a further implementation is provided in which the metal material matrix is ​​wear-resistant steel BISPLATE 400.

[0015] The present invention also provides a metallic material having a surface coating, wherein the surface coating is prepared by the method described above.

[0016] Beneficial effects of the present invention This invention discloses a method for rapidly preparing coatings on the surface of metal materials based on flash sintering technology. The method involves setting appropriate flash sintering current, sintering pressure, and sintering time according to the desired coating composition, thickness, and substrate material. Simultaneously, the pressure is adjusted in real-time based on pressure changes during flash sintering to maintain a constant sintering pressure until the flash sintering process is complete. The entire process lasts only 10-300 seconds. This method overcomes the problems of low efficiency, high equipment cost, and weak adhesion in traditional methods for preparing coatings on material surfaces, thereby improving production efficiency and reducing production costs. Attached Figure Description

[0017] Figure 1 Schematic diagram of the sintering apparatus in the flash sintering process for preparing surface coatings; Figure 2 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2 kA, a sintering pressure of 2 t, and a sintering time of 30 s. Figure 3 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2kA, a sintering pressure of 2t, and a sintering time of 40s. Figure 4 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2 kA, a sintering pressure of 2 t, and a sintering time of 50 s. Figure 5 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2 kA, a sintering pressure of 5 t, and a sintering time of 30 s. Figure 6 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2kA, a sintering pressure of 5t, and a sintering time of 40s. Figure 7 This is a schematic diagram of the coating prepared in Example 1 with a sintering current of 3.2kA, a sintering pressure of 5t, and a sintering time of 50s. Figure 8 This is a flowchart of the method of the present invention. Detailed Implementation

[0018] To better understand the technical solution of this invention, the content of this invention includes, but is not limited to, the specific embodiments described below. Similar technologies and methods should be considered within the scope of protection of this invention. To make the technical problems to be solved, the technical solutions, and advantages of this invention clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments.

[0019] It should be understood that the embodiments described in this invention are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0020] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0021] like Figure 1 As shown, the sintering apparatus of the present invention includes: a hydraulic device and pressure sensor 1, an alloy conductive plate 2, a flash sintering cylindrical mold 3, a corundum ceramic tube 4, a tungsten electrode 5, graphite paper 6, M2-TiC mixed powder 7, a wear-resistant steel substrate 8, and a lower copper electrode 9. In this apparatus, the alloy conductive plate 2 contacts the upper copper electrode to form a circuit, and its lower side is connected to the tungsten electrode 5. To prevent adhesion between the coating and the electrode after preparation, graphite paper 6 is laid below the tungsten electrode 5 as an isolation layer. Below the graphite paper 6 are the powder 7 required for coating preparation and the wear-resistant steel substrate 8, respectively. The overall structure is externally wrapped and fixed by the cylindrical heat-resistant mold 3 and the ceramic tube 4, and the lower copper electrode 9 is connected at the bottom of the apparatus, thus forming a complete circuit. The upper and lower copper electrodes are respectively connected to a pulse power supply.

[0022] The arrows in the diagram indicate the direction of applied pressure. The lower copper electrode 9 is the anode, and the upper copper electrode is the cathode.

[0023] Traditional methods for preparing coatings on substrate surfaces, such as thermal spraying, physical deposition, and chemical deposition, suffer from problems such as weak interfacial adhesion, long preparation time, and significant environmental pollution. However, this invention utilizes a pulsed current flash sintering process to prepare materials with high density, short sintering time, and high product density. This technology achieves high-strength bonding between the coating and the substrate through instantaneous high temperature and electric field effects, while maintaining excellent microstructure density and performance consistency. Its application in preparing coatings on material surfaces shows significant potential. Based on this, this invention proposes a method for rapidly preparing coatings on metallic material surfaces using flash sintering technology.

[0024] like Figure 8 As shown, according to one aspect of the present invention, the present invention provides the following technical solution: A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology includes the following steps: S1: Polish and clean the surface of the substrate to be coated in order to maintain its conductivity during the flash sintering process; S2: Prepare, proportion, and mix the powder according to the required coating; S3: Place the matrix and the mixed powder into a cylindrical sintering mold. First, fit a corundum ceramic tube 4 with an inner diameter of 11.8mm~12mm into the sintering mold 3. Then, add the metal matrix 8 and the coating powder 7 into the ceramic tube 4 in sequence. Separate the powder 7 from the upper tungsten electrode 5 with graphite paper 6 to prevent the coating from sticking to the tungsten electrode 5.

[0025] S4: The alloy conductive plate 2 is brought into contact with the upper copper electrode to form a circuit, and its lower side is connected to the tungsten electrode 5. To prevent the coating from sticking to the electrode after preparation, graphite paper 6 is laid under the tungsten electrode 5 as an isolation layer. Below the graphite paper 6 are the powder 7 and the substrate 8 required for coating preparation. The overall structure is externally wrapped and fixed by a cylindrical heat-resistant mold 3 and a ceramic tube 4. The lower copper electrode is connected at the bottom of the device to form a complete circuit, and flash sintering is performed to complete the coating preparation on the material surface.

[0026] Preferably, in step S1, the surface of the substrate to be treated is polished sequentially with 400-800 grit, 1000-1400 grit, and 1800-2500 grit sandpaper.

[0027] Preferably, in step S2, the TiC powder in the TiC-M2 iron-based composite material has a particle size of 1μm~3μm, and the M2 high-speed steel powder has a particle size of 15~53μm; the powder is mixed by a high-speed ball mill with a rotation speed of 50~500r / min, and after ball milling for 30min, the direction is reversed, with a 10min interval between reversals to prevent the stainless steel balls from overheating; the ball milling time is 1h~20h, and the density of the iron-based composite material formed under the above particle size and ball milling conditions can reach ≥95%.

[0028] Preferably, in step S3, the corundum ceramic tube has an inner diameter of 11.8 mm to 12 mm. This size allows the powder 7 to be spread evenly on the surface of the metal material matrix 8 and crushed after sintering to prevent it from sticking to the mold.

[0029] Preferably, in step S4, the hydraulic device and pulse power supply apply high pressure and high current density to the M2-TiC mixed powder 7 in the flash sintering assembly through the upper and lower pressure heads and copper electrodes, respectively. The pressure sensor 1 is located at the pressure head position of the hydraulic device. The pulse current parameters are: 0.5kA~5kA, current frequency is 100~20000Hz, sintering time is 10s~300s, and sintering pressure is 0.1t~5t, which are provided by the hydraulic device and displayed by a pressure gauge.

[0030] Preferably, in step S4, during the sintering process, since the M2 powder in the mixed powder has a lower melting point, the gaps between the powders provide high resistance. At this time, the M2 powder is liquefied by heating with electricity, and the liquid phase fills the gaps between the mixed powders. At this time, the pressure changes, and the pressure of the flash sintering process is kept constant by using a hydraulic jack. After the pulse power is turned off, it is rapidly cooled and solidified to form a dense coating on the surface of the material matrix.

[0031] Preferably, in step S4, parameters such as pulse current, pressure, and mixed powder mass are set according to the required coating composition and thickness, specifically as follows: A mixed powder containing 10%~40% TiC-M2 was used. (4.57×10) -3 g / mm 2 ~2.29×10 -2 g / mm 2 When preparing a TiC-M2 iron-based composite coating with a thickness of (0.5,1] μm, the flash sintering parameters are a pulse current of 2.5 kA to 3.2 kA, a sintering pressure of 1 t to 5 t, and a sintering time of 10 s to 300 s. A mixed powder containing 10%–40% TiC-M2 was used at a concentration of 1.7 × 10⁻⁶. -2 g / mm 2 ~3.5×10 -2 g / mm 2When preparing TiC-M2 iron-based composite material coatings with a thickness of (1, 1.5] μm, the pulse current for flash sintering is 2.7 kA to 3.5 kA, the sintering pressure is 1 t to 5 t, and the sintering time is 10 s to 300 s.

[0032] As an embodiment of the present invention, the present invention also provides a metal material with a surface coating. The surface coating of the metal material is prepared by the method described in the present invention. According to the powder ratio for preparing the coating, the wear resistance, corrosion resistance, heat resistance and other required properties of the metal substrate with the coating can be effectively improved.

[0033] The technical solution of the present invention will be further described below with reference to specific embodiments. The technical solutions and technical problems solved in the embodiments of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0034] Example 1 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: TiC powder with a particle size of 1-3μm and M2 high-speed steel powder with a particle size of 15-53μm are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder. S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 2t. The coating preparation on the material surface is completed in 30s, and its cross-sectional effect is as follows. Figure 2As shown, under sintering conditions of 3.2 kA-2t-30s, a relatively dense coating with only a small amount of unmelted TiC regions can be observed.

[0035] Example 2 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: 1-3μm TiC powder and 15-53μm M2 high-speed steel powder are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder; S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 2t. The coating preparation on the material surface is completed in 40s, and its cross-sectional effect is as follows. Figure 3 As shown, under sintering conditions of 3.2 kA-2t-40s, a relatively dense coating with almost no unmelted TiC region was observed. The Vickers hardness of the surface coating was 900~1200 HV, compared to the Vickers hardness of the substrate of 400~500 HV. Hardness is closely related to the wear resistance of the material, indicating that the wear resistance of the material was significantly improved after the coating was prepared.

[0036] Example 3 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: 1-3μm TiC powder and 15-53μm M2 high-speed steel powder are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder; S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 2t. The coating preparation on the material surface is completed in 50s, and its cross-sectional effect is as follows. Figure 4 As shown, under sintering conditions of 3.2 kA-2t-50s, a relatively dense coating cross-section was observed, with no unmelted TiC regions observed. The TiC was uniformly distributed (the black areas in the scanning electron microscope image), and the interface with the substrate was smooth. The Vickers hardness of the surface coating was 1100-1200 HV, compared to 400-500 HV for the substrate. Hardness is closely related to the wear resistance of the material, indicating that the wear resistance of the material was significantly improved after the coating was prepared.

[0037] Example 4 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: 1-3μm TiC powder and 15-53μm M2 high-speed steel powder are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder; S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 5t. The coating preparation on the material surface is completed in 30s, and its cross-sectional effect is as follows. Figure 5 As shown, under the sintering conditions of 3.2kA-5t-30s, the coating cross-section exhibits a large number of protrusions and depressions, indicating that a large amount of TiC powder in the composite material is not completely melted. The sintering pressure is greater than that under the 3.2kA-2t-30s treatment conditions, which leads to a reduction in the voids between the powders and a reduction in the resistance between the materials. This results in less heat generated under the same current conditions, thus leading to a poorer sintering effect.

[0038] Example 5 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: 1-3μm TiC powder and 15-53μm M2 high-speed steel powder are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder; S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 5t. The coating preparation on the material surface is completed in 40s, and its cross-sectional effect is as follows. Figure 6 As shown, under the sintering conditions of 3.2 kA-5t-40s, it can be observed that the coating cross section still has a morphology of protrusions and depressions, indicating that the TiC powder in the composite material is still incompletely dissolved and solidified.

[0039] Example 6 A method for rapidly preparing coatings on the surface of metallic materials based on flash sintering technology, using wear-resistant steel BISPLATE 400 as the substrate, cut into cylinders with a diameter of 11.8 mm and a thickness of 3-5 mm by wire EDM as the substrate for coating preparation; preparing TiC powder with a particle size of 1-3 μm and M2 high-speed steel powder with a particle size of 15-53 μm as raw materials for preparing the iron-based composite coating; including the following steps: S1: Grind and clean the surface of BISPLATE 400 wear-resistant steel with a diameter of 11.8mm to maintain its conductivity during the flash sintering process; S2: 1-3μm TiC powder and 15-53μm M2 high-speed steel powder are mixed by high-speed ball milling at a ratio of 10%~40% TiC-M2 powder; S3: To prevent the coating from sticking to the electrode after preparation, graphite paper is laid under the tungsten electrode as an isolation layer. Underneath the graphite paper is a mixed powder and a BISPLATE 400 wear-resistant steel substrate with a diameter of 11.8 mm and a height of 3~5 mm. These three parts constitute the sintering material. The upper side of the alloy conductive plate is in contact with the copper electrode, and the lower side is in contact with the tungsten electrode in the sintering material. The sintering mold and the sintering material are separated by a ceramic tube. The overall structure is wrapped and fixed by a cylindrical heat-resistant mold and a ceramic tube. The bottom of the device is connected to the lower copper electrode, thus forming a complete circuit. S4: The materials stacked according to S3 are subjected to flash sintering, with the pulse current set to 3.2kA and the sintering pressure to 5t. The coating preparation on the material surface is completed in 50s, and its cross-sectional effect is as follows. Figure 7 As shown, under the sintering conditions of 3.2kA-5t-50s, a small number of protrusions and depressions can be observed in the cross-section of the coating, indicating that the TiC powder in the composite material is still not completely melted. However, under the condition of constant pressure, the degree of dissolution and solidification of TiC powder in the coating gradually improves with the extension of sintering time, but there is still a large gap compared with the treatment conditions of 3.2kA-2t. This shows that in different coating preparation processes, only the adjustment of multiple parameters such as sintering pressure, sintering time and current is needed to prepare coatings with optimal service performance.

[0040] As can be seen from the above embodiments, depending on the composition, thickness, and substrate material of the desired coating, the corresponding flash sintering current, sintering pressure, and sintering time are set. Simultaneously, the pressure is adjusted in real time according to the pressure changes during flash sintering to maintain a constant sintering pressure until the flash sintering process ends; the entire process lasts only 10s to 300s. The method of this invention can improve the problems of low efficiency, high equipment cost, and weak adhesion in coating preparation on material surfaces, thereby increasing production efficiency and reducing production costs.

[0041] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for rapidly preparing a coating on the surface of a metallic material, characterized in that, Includes the following steps: S1. Grind and clean the surface of the metal substrate to which the coating is to be prepared; S2. Prepare the raw material powder according to the desired coating; S3. Place the cleaned matrix and the prepared powder into a sintering mold; S4. Flash sintering is performed in a sintering mold to complete the coating preparation on the substrate surface.

2. The method according to claim 1, characterized in that, In step S1, the substrate surface is polished sequentially with 400-800 grit, 1000-1400 grit, and 1800-2500 grit sandpaper.

3. The method according to claim 1, characterized in that, The coating is a TiC-M2 iron-based composite material, which is made from two raw material powders: TiC powder and M2 high-speed steel powder. The two powders are mixed by a high-speed ball mill with a speed of 50~500 r / min. After ball milling for 30 min, the direction is reversed, and the direction is reversed again after an interval of 10 min. The ball milling time is 1h~20h.

4. The method according to claim 1, characterized in that, In S3, the sintering mold and the sintering material are separated by a ceramic tube, and the upper side of the raw material powder is separated from the upper tungsten electrode of the sintering mold by graphite paper.

5. The method according to claim 3, characterized in that, The TiC powder has a particle size of 1μm to 3μm, and the M2 high-speed steel powder has a particle size of 15 to 53μm.

6. The method according to claim 1, characterized in that, The sintering in S4 is performed using a pulsed current, wherein the pulsed current is 0.5kA~5kA, the current frequency is 100~20000Hz, the sintering time is 10s~300s, and the sintering pressure is 0.1t~5t. The pressure is provided by a jack and displayed by a pressure gauge.

7. The method according to claim 1, characterized in that, S4 specifically includes: setting pulse current, pressure, and mixed powder quality parameters according to the composition of the prepared coating and the required thickness, specifically as follows: When preparing a TiC-M2 iron-based composite coating with a thickness of (0.5, 1] ​​μm, 5 × 10⁻⁶ mixed powders containing 10%~40% TiC-M2 were used. -3 g / mm 2 ~2.3×10 -2 g / mm 2 The flash sintering pulse current is 2.5kA to 3.2kA, the sintering pressure is 1t to 5t, and the sintering time is 10s to 300s. When preparing a TiC-M2 iron-based composite coating with a thickness of (1, 1.5] μm, a mixed powder containing 10%–40% TiC-M2 was used at a density of 1.7 × 10⁻⁶ μm. -2 g / mm 2 ~3.5×10 -2 g / mm 2 The pulse current for flash sintering is 2.7kA to 3.5kA, the sintering pressure is 1t to 5t, and the sintering time is 10s to 300s.

8. The method according to claim 4, characterized in that, The ceramic tube has an inner diameter of 11.8mm to 12mm and is broken after sintering to prevent it from sticking to the sintering mold.

9. The method according to claim 6, characterized in that, The metal material matrix is ​​wear-resistant steel BISPLATE400.

10. A metallic material having a surface coating, characterized in that, The surface coating is prepared by the method described in any one of claims 1-9.

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