Method for forming high-bonding-strength coating on alloy surface

Abstract

The invention discloses a method for forming a high-bonding-strength coating on an alloy surface, which comprises the following steps: carrying out irradiation treatment on the alloy surface by using a high-current pulsed electron beam process to form a compact remelting layer on the alloy surface, wherein the roughness Ra of the compact remelting layer is less than or equal to 1 mu m, and the compact remelting layer has a high-energy-state structure with rich slippage and ultra-fine grains; and performing vapor deposition on the surface of the alloy by using a vapor deposition process to form a high-bonding-strength coating on the surface of the alloy. According to the method for forming the high-bonding-strength coating on the surface of the alloy, the microstructure state of the surface of the alloy matrix before deposition is modified through the high-current pulsed electron beam (HCPEB) technology, that is, extreme treatment conditions are generated through the energy thermal-mechanical coupling effect, so that the film forming conditions of the alloy matrix are optimized, and the bonding strength of the alloy matrix is improved. And the growth mode of the vapor deposition coating is changed, so that the bonding strength and the use performance of the coating are improved, and the service life of the coating is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of vapor deposition, and in particular relates to a method for forming a high-bonding-strength coating on an alloy surface. Background Art

[0002] Vapor deposition technology is a new coating preparation technology developed in recent decades. Through physical or chemical processes, a layer of thin film or coating with specific functions is formed on the surface of the substrate material. This technology is widely used in new tool coatings, aerospace high-temperature blade coatings, optical coatings and other fields. Its main working characteristics are: working in a vacuum environment, evaporating or sputtering the target material to form atomic or molecular gas phase substances, which are adsorbed on the surface of the substrate to form a single or multi-layer atomic adsorption layer; then, at a certain temperature, the atoms adsorbed on the surface of the substrate will diffuse; when the number of atoms adsorbed on the surface of the substrate reaches a certain concentration, they will polymerize into molecules or crystals through chemical bonding; as the deposition time increases and the temperature rises, the number of polymerized molecules or crystals will gradually increase, and finally form a continuous coating. This coating growth process of condensation, nucleation, growth, and film formation at the atomic level can theoretically evaporate and sputter targets of any material by adjusting relevant process parameters. However, it should be noted that in the actual preparation process of vapor deposition coatings, due to the influence of the microstructural state of the substrate surface, such as rough surface, holes, microcracks and metal inclusions, the growth direction of the crystals is random, which will increase the internal stress of the vapor deposition coatings prepared by most ordinary processes, and the lack of toughness will easily lead to cracking, which is obviously not conducive to the interface bonding and performance of this type of coating with the substrate.

[0003] At present, many researchers are committed to optimizing the bonding strength and performance of coatings through various treatment methods. The most common method is to perform surface treatment on the substrate. The patent "A method for improving the bonding strength of gear DLC coating based on shot peening treatment (publication number CN116814921A)" proposes a method for improving the bonding strength of gear DLC coating by shot peening treatment, that is, using shot peening to treat the surface of the gear workpiece, improving the residual stress and roughness of the gear surface, thereby changing the bonding force with the coating particles and increasing the bonding strength. Although this method improves the bonding effect of the coating to a certain extent, it is inevitable that the surface defects of the substrate cannot be eliminated, and shot peening may cause large-scale plastic deformation on the surface of the substrate, which will be detrimental to the coating forming effect of precision workpieces. In addition, the patent "An ultrasonic cleaning device for improving the bonding force of the coating (publication number CN219880784U)" proposes an ultrasonic cleaning device for improving the bonding force of the coating. The inventive method improves the bonding quality of the coating by fully cleaning the impurities and dirt on the surface of the workpiece. However, this method only improves the cleanliness of the substrate surface, and does not improve the morphological state of the substrate surface. Summary of the invention

[0004] Based on the above technical problems, the present invention provides a method for forming a high bonding strength coating on an alloy surface, which uses high-current pulsed electron beam (HCPEB) technology to modify the microstructural state of the surface of the alloy substrate before deposition, that is, to generate extreme processing conditions through energy thermal coupling, thereby optimizing the film forming conditions of the alloy substrate, changing the growth mode of the vapor deposited coating, thereby improving the bonding strength and performance of the coating, and extending the service life of the coating.

[0005] The present invention proposes a method for forming a high-bonding strength coating on an alloy surface, comprising: irradiating the alloy surface with a high-current pulsed electron beam process to form a dense remelted layer, a roughness as low as Ra≤1μm, and a high-energy state structure with rich slip and ultrafine grains on the alloy surface; and then performing vapor deposition on the alloy surface using a vapor deposition process to form a high-bonding strength coating on the alloy surface.

[0006] In the present invention, the surface of the alloy substrate is preliminarily remelted and polished by using a high-current pulsed electron beam (HCPEB) technology to repair its surface tissue defects and produce a dense remelted layer, a high-energy surface structure with rich slip systems and ultrafine grains; in the subsequent vapor phase atomic deposition process, the surface of the high-energy coating is more likely to capture atomic clusters to form crystal nuclei, resulting in an increase in the atomic nucleation rate, which is conducive to obtaining a finer columnar crystal structure at the interface, so that a layer of flat and dense equiaxed crystals is quickly generated on the deposition surface; in addition, the dense and fine microstructure at the interface significantly improves the atomic diffusion capacity, which can greatly improve the bonding strength and performance of the subsequent vapor phase deposition coating.

[0007] Preferably, the alloy is at least one of DZ125 alloy, YG6 cemented carbide or GH4169 high temperature alloy.

[0008] Preferably, the parameters of the high-current pulsed electron beam process include: vacuum degree ≤ 5.5×10 -3 Pa, irradiation voltage is 27-30KeV, energy density is 7-15J / cm 2 , pulse width time is 1-1.5μs, irradiation times are 25-35 times, overlap rate is 50-60%, and working distance is 20-30cm.

[0009] In the present invention, the parameters of the high-current pulsed electron beam process need to be controlled to ensure that the surface of the alloy matrix is ​​remelted and polished, its surface tissue defects are repaired and a dense remelted layer, rich slip systems and ultrafine grains of high-energy surface structures are produced.

[0010] In actual operation, the HCPEB irradiation strengthening process parameters are debugged using test pieces consistent with the alloy material. Specifically, the HCPEB strengthening process effect can be set according to the material parameter characteristics of the alloy (material parameters include element composition, melting point, hardness, phase structure, etc.) and geometric structure characteristics, and then the strengthening effect obtained by the sample is characterized and analyzed by adjusting parameters such as the number of irradiations, energy density and pulse width time, so as to determine the optimal process parameters of HCPEB; after the optimal process parameters of HCPEB are determined, the alloy matrix is ​​subjected to irradiation strengthening treatment.

[0011] Preferably, when the alloy is DZ125 alloy, the parameters of the high-current pulsed electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, irradiation times is 25 times, overlap rate is 50%, working distance is 30cm;

[0012] When the alloy is YG6 cemented carbide, the parameters of the high-current pulse electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 30KeV, energy density is 7J / cm 2 , pulse width time is 1μs, irradiation times is 35 times, overlap rate is 60%, working distance is 25cm;

[0013] When the alloy is GH4169 high temperature alloy, the parameters of the high current pulse electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, irradiation times is 30 times, overlap rate is 50%, and working distance is 20cm.

[0014] Preferably, the vapor deposition process includes an electron beam physical vapor deposition process (EB-PVD), an arc ion plating process (AIP), a magnetron sputtering deposition process (MS) or a chemical vapor deposition process (CVD).

[0015] Preferably, the coating includes a NiAl coating, a TiCN coating or a NiCoCrAlY coating.

[0016] Preferably, the NiAl coating is formed by electron beam physical vapor deposition process, and the process parameters include: substrate heating temperature is 850°C, evaporation chamber vacuum degree is 10 -3 Pa, the electron beam current is 1.5A, the workpiece turret speed is 15r / min, and the deposition rate is 2.5μm / min;

[0017] The TiCN coating is formed by chemical vapor deposition process, and the process parameters include: substrate heating temperature is 885°C, pressure is 60kPa, carrier gas is H2, C and N sources are CH3CN, Ti source is TiCl4, and the gas ratio of TiCl4 to CH3CN is 2:1;

[0018] The NiCoCrAlY coating is formed by arc ion plating process, and the process parameters include: arc current of 75A, arc voltage of 20V, substrate bias of -100V, and duty cycle of 60%.

[0019] In the present invention, when the alloy substrate is processed by vapor deposition coating, the processing technology is adjusted to ensure that the coating has good preparation effect and service performance.

[0020] Preferably, the alloy surface is pre-grinded and cleaned before being irradiated.

[0021] Preferably, after the alloy surface is subjected to vapor deposition, the high bonding strength coating is subjected to vacuum heat treatment;

[0022] The process parameters of the vacuum heat treatment include: vacuum degree ≤10 -3 Pa, heating temperature is 900-1050℃, and holding time is 4-5h.

[0023] In the present invention, in order to reduce or eliminate the internal stress generated during the preparation process and promote element diffusion to increase the interface bonding strength between the coating and the substrate, vacuum heat treatment, namely annealing treatment, is required if necessary.

[0024] Beneficial effects of the present invention:

[0025] The innovation of the present invention is:

[0026] The present invention is an innovative new process method for vapor deposition coating. The surface of the alloy substrate before vapor deposition is treated by using high-current pulsed electron beam technology, and the surface microstructure, component distribution, residual stress and roughness of the alloy substrate are regulated through a series of physical / chemical / mechanical processes such as deformation, phase change, melting and even evaporation. Subsequently, the genetic effect of the growth of the vapor deposition coating is utilized to obtain better bonding strength and growth mode on the surface of the high-energy state substrate after strengthening, thereby effectively improving the service performance of the alloy workpiece and providing innovative process guidance for the preparation of high-performance vapor deposition coatings.

[0027] The present invention has the following advantages:

[0028] (1) After treatment with high-current pulsed electron beam technology, a reinforced remelting layer can be formed on the surface of the substrate, which can effectively remove the surface defects of the original substrate, regulate the surface roughness, refine the surface grains, and form a high-density dislocation structure, significantly improving the surface state of the substrate.

[0029] (2) Compared with shot peening and sand blasting, high-current pulsed electron beam technology can obtain a deeper treatment layer through the effect of pure energy transfer and thermal coupling. In addition, since the strengthening process is carried out in a high vacuum, the generation of pollution during shot peening and sand blasting is avoided.

[0030] (3) The high-current pulsed electron beam process strengthens and regulates the surface morphology of the substrate, which plays a very important role in the growth behavior of the subsequent atmospheric deposition coating. The substrate surface obtains a mirror polishing effect, effectively reducing the roughness, thereby reducing the tilted shielding effect of the first-grown large-size columnar crystals, thereby obtaining a dense and defect-free coating effect; a high-density dislocation and fine-grained structure are generated inside the remelted layer, providing a large number of channels for the diffusion of atoms, enhancing the interface diffusion capacity of atoms, and thus improving the interface bonding strength of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The surface and cross-sectional microstructures of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1 are shown in FIG. 1-3 ) is the surface cross-section microstructure diagram of the original DZ125 alloy, (b 1-3 ) is the surface and cross-section microstructure diagram of DZ125 alloy after HCPEB irradiation modification;

[0032] Figure 2 The surface and cross-sectional microstructures of the NiAl coating deposited on the surface of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1: the left side is the surface and cross-sectional microstructure of the NiAl coating deposited on the surface of the original DZ125 alloy, and the right side is the surface and cross-sectional microstructure of the NiAl coating deposited on the surface of the DZ125 alloy modified by HCPEB irradiation;

[0033] Figure 3 The following are the film-substrate bonding strength diagrams of the NiAl coating deposited on the surface of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1: (a) is the film-substrate bonding strength diagram of the NiAl coating deposited on the surface of the original DZ125 alloy, and (b) is the film-substrate bonding strength diagram of the NiAl coating deposited on the surface of the DZ125 alloy modified by HCPEB irradiation. DETAILED DESCRIPTION

[0034] Hereinafter, the present invention will describe the technical solution in detail through specific embodiments, but it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0035] Example 1

[0036] This embodiment provides a method for forming a high bonding strength coating on an alloy surface, comprising the following steps:

[0037] (1) After pre-grinding the DZ125 alloy substrate, use acetone to clean and remove oil stains and dirt on its surface;

[0038] (2) The HCPEB process was used to irradiate and modify the DZ125 alloy matrix after the above pretreatment. The specific process parameters were: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, number of irradiation is 25 times, overlap rate is 50%, working distance is 30cm. After irradiation modification under the process parameters, MC carbides on the surface of DZ125 alloy matrix disappear, ultrafine grain structure appears, the thickness of remelting treatment layer is 4.5μm, the surface is smooth and uniform, the roughness is only Ra≈0.5μm, and the molten pit structure disappears;

[0039] (3) The NiAl coating was vapor deposited on the DZ125 alloy substrate after the irradiation modification by EB-PVD process. The specific process parameters were: substrate heating temperature of 850 °C, vacuum degree of evaporation chamber of 10 -3 Pa, electron beam current of 1.5A, workpiece rotating rack speed of 15r / min, deposition rate of 2.5μm / min, NiAl coating thickness of 30μm, after vapor deposition under the process parameters, a NiAl coating with high bonding strength is formed on the surface of the DZ125 alloy substrate;

[0040] (4) The DZ125 alloy substrate with the NiAl coating deposited thereon is subjected to vacuum heat treatment by a heat treatment process, and the specific process parameters are as follows: vacuum degree is 10 -3 Pa, heating temperature is 1050℃, and holding time is 4h. After vacuum heat treatment under this process parameter, the internal stress generated in the preparation process is reduced or eliminated, the element diffusion is promoted, and the interface bonding strength is further increased.

[0041] Figure 1 The surface and cross-sectional microstructures of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1. Figure 1It can be seen that the surface of the original DZ125 alloy matrix (i.e., without HCPEB irradiation modification) is mainly composed of γ / γ' phase, with a large number of large-sized hard and brittle MC carbides. TCP phase is easily precipitated at high temperature and easily becomes the crack initiation point of the coating, which will be detrimental to the high-temperature performance and bonding performance of the coating. The original DZ125 alloy matrix without HCPEB irradiation modification is obviously different from the original DZ125 alloy matrix without HCPEB irradiation modification. The DZ125 alloy matrix after HCPEB irradiation modification will be accompanied by extremely rapid cooling and directional solidification process after HCPEB pulse irradiation, and induces huge stress at ultra-high strain rate, so that the large-particle MC carbide on the surface of the DZ125 alloy matrix will be dissolved, and the grains will be ultra-fine and the deformation structure with rich slip system will be produced, which will eventually purify the surface of the material, homogenize the composition, change the surface phase, ultra-fine the grains, and produce rich crystal defects and deformation structure, and obtain a dense and defect-free surface. Through cross-sectional observation, due to the HCPEB heating and remelting effect, a dense remelted layer with a thickness of 4.5 μm is produced near the surface of the DZ125 alloy substrate. This irradiation strengthening effect provides good film growth conditions for subsequent coating deposition.

[0042] Referring to the method of the above embodiment, omitting step (2), a NiAl coating can also be formed on the surface of the DZ125 alloy substrate. The NiAl coating is deposited on the surface of the original DZ125 alloy. The NiAl coating and the NiAl coating deposited on the surface of the DZ125 alloy substrate modified by HCPEB irradiation in the above embodiment are detected by scanning electron microscopy. The results are as follows: Figure 2 As shown, Figure 2 The cross-sectional microstructure of the NiAl coating deposited on the surface of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1. Figure 2 It can be seen that the surface of the NiAl coating deposited on the original DZ125 alloy has undulations and local microcracks, with a roughness of Ra≈14μm. A large number of holes are found near the substrate interface on the cross section, and obvious cracks are found on the coating cross section. The mutual diffusion distance between the coating and the substrate is only 5.18μm, and the coating preparation effect is poor. The NiAl coating deposited on the surface of the DZ125 alloy modified by HCPEB irradiation has a significant improvement effect. The coating surface is flat, uniform, crack-free, and the grains are extremely small. The roughness is only Ra≈5.6μm, the cross section is straight and defect-free, and the mutual diffusion distance between the coating and the substrate is 10.38μm, which is twice that of the original coating. The improvement of the latter effect is due to the HCPEB irradiation strengthening of the DZ125 alloy matrix to produce ultrafine grains and rich crystal defects and deformation structures, and the genetic growth effect of EB-PVD vapor deposition is used to greatly reduce the grain size of the coating surface; in addition, the strengthening effect provides a short-circuit channel for the rapid diffusion of coating elements, thereby increasing the diffusion distance, which will be beneficial to the improvement of interface bonding performance.

[0043] Figure 3 The figure shows the film-substrate bonding strength of the NiAl coating deposited on the surface of the original DZ125 alloy and the DZ125 alloy modified by HCPEB irradiation in Example 1. Figure 3 It can be seen that the NiAl coating deposited on the surface of the original DZ125 alloy has Figure 2 The local cracks and holes shown have an average critical load of 67.68N; the bonding strength of the NiAl coating deposited on the surface of the DZ125 alloy modified by HCPEB is greatly improved, and the average critical load is increased to 130.02N, an increase of 92% compared with the original.

[0044] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×10 -3 Pa, irradiation voltage is 15KeV, energy density is 5J / cm 2 , pulse width time is 1μs, number of irradiation times is 20 times, overlap rate is 50%, working distance is 30cm. After irradiation modification under the process parameters, there are still a large number of undissolved MC carbides on the surface of the DZ125 alloy matrix, and no obvious ultrafine grain structure is found. The thickness of the remelting treatment layer is about 3.2μm. At the same time, there are a large number of eruption crater-like molten pit structures on the surface of the material. This is because during the irradiation process, the sub-surface low-melting point impurities expand in volume and break through the surface tension to erupt to the outside of the material. In addition, the shock wave brought by the molten pit eruption causes strong plastic deformation on the surface of the material, causing a wavy molten structure with a large roughness, which increases the surface roughness of the material to Ra≈2.5μm.

[0045] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×10 -3 Pa, irradiation voltage is 40KeV, energy density is 25J / cm 2 , pulse width time is 2μs, number of irradiations is 40 times, overlap rate is 50%, working distance is 30cm. After irradiation modification under the process parameters, there is no MC carbide on the surface of the DZ125 alloy matrix, and the thickness of the remelted layer has not increased significantly, only about 5μm. In addition, due to heat accumulation on the material surface under high energy density, the grains grow and coarsen, and the surface roughness of the material under this parameter is again increased to Ra≈3μm.

[0046] From the above comparison, it can be seen that the surface characteristics of the DZ125 alloy matrix are quite different after irradiation modification under different process parameters. Only by controlling the process parameters so that its macroscopic surface is completely polished and remelted, the roughness is reduced to Ra≤1μm, and the large MC carbide defects on the surface are repaired on the microstructure so that they are dissolved into the matrix, a dense remelted layer, rich nano-scale grains and slip structures are produced, can the subsequent vapor deposition coating growth be improved, thereby obtaining a higher coating interface bonding strength.

[0047] Example 2

[0048] This embodiment provides a method for forming a high bonding strength coating on an alloy surface, comprising the following steps:

[0049] (1) After pre-grinding, the YG6 (WC-Co) cemented carbide substrate was cleaned with alcohol to remove oil stains and dirt on its surface;

[0050] (2) The YG6 cemented carbide substrate after the above pretreatment was irradiated and modified by HCPEB process. The specific process parameters were as follows: vacuum degree was 5.5×10 -3 Pa, irradiation voltage is 30KeV, energy density is 7J / cm 2 , pulse width time is 1μs, number of irradiation is 35 times, overlap rate is 60%, working distance is 25cm. After irradiation modification under the process parameters, nano-scale fine grain structure appears on the surface of YG6 cemented carbide substrate, the thickness of the remelting treatment layer is 5.1μm, the surface is smooth and uniform, the roughness is only Ra≈0.7μm, and the molten pit structure disappears;

[0051] (3) The TiCN coating was vapor-deposited on the YG6 cemented carbide substrate after the irradiation modification by CVD process. The process parameters were as follows: substrate heating temperature was 885°C, pressure was 60 kPa, carrier gas was H2, the sources of C and N in the process were CH3CN, the source of Ti was TiCl4, the gas ratio of TiCl4 to CH3CN was 2:1, and the thickness of the TiCN coating was 10 μm. After vapor deposition under the process parameters, a TiCN coating with high bonding strength was formed on the surface of the YG6 cemented carbide substrate.

[0052] (4) The YG6 cemented carbide substrate with the TiCN coating deposited thereon is subjected to vacuum heat treatment by a heat treatment process, and the specific process parameters are as follows: vacuum degree is 10 -3 Pa, heating temperature is 1000℃, and holding time is 5h. After vacuum heat treatment under this process parameter, the internal stress generated in the preparation process is reduced or eliminated, the element diffusion is promoted, and the interface bonding strength is further increased.

[0053] In the above embodiment, the surface of the YG6 (WC-Co) cemented carbide substrate modified by HCPEB irradiation is defect-free, and a large number of nano-scale grains and rich crystal defects and deformation structures are produced; the surface roughness of the TiCN coating deposited on the surface of the YG6 (WC-Co) cemented carbide modified by HCPEB is reduced from the original Ra≈5.76μm to 1.01μm. In addition, compared with the TiCN coating deposited on the surface of the original YG6 (WC-Co) cemented carbide substrate, the bonding strength of the former is significantly improved, and the average critical load is increased from the original 77N to 135N.

[0054] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×10 -3 Pa, irradiation voltage is 10KeV, energy density is 6J / cm 2 , pulse width time is 0.5μs, number of irradiation times is 10 times, overlap rate is 50%, working distance is 25cm. After irradiation modification under the process parameters, no obvious ultrafine grain structure is found on the surface of YG6 cemented carbide substrate, and the thickness of the remelting treatment layer is about 1.8μm. At the same time, there are a large number of eruption crater-like molten pits and ripple-state molten structures on the surface of the material, which increases the surface roughness of the material to Ra≈3.5μm;

[0055] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×10 -3 Pa, irradiation voltage is 45KeV, energy density is 25J / cm 2 , pulse width time is 2μs, irradiation times are 50 times, overlap rate is 50%, working distance is 25cm. After irradiation modification under the process parameters, the thickness of the remelting layer of the YG6 cemented carbide substrate does not increase significantly, only 5.5μm. In addition, due to the heat accumulation on the surface of the material under high energy density, the grains also grow and coarsen. Under this parameter, the surface roughness of the material is again increased to Ra≈4.9μm;

[0056] From the above comparison, it can be seen that the surface characteristics of the YG6 cemented carbide substrate after irradiation modification under different process parameters are quite different. Only by controlling the process parameters so that its macroscopic surface is completely polished and remelted, the roughness is reduced to Ra≤1μm, there are no organizational defects in the microstructure, a dense remelted layer is produced, and nano-scale grains and slip structures are enriched, can the subsequent vapor deposition coating growth be improved, thereby obtaining a higher coating interface bonding strength.

[0057] Example 3

[0058] This embodiment provides a method for forming a high bonding strength coating on an alloy surface, comprising the following steps:

[0059] (1) After pre-grinding, the GH4169 high-temperature alloy substrate was cleaned with acetone to remove oil stains and dirt on its surface;

[0060] (2) The HCPEB process was used to irradiate and modify the GH4169 high-temperature alloy substrate after the above pretreatment. The specific process parameters were: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, irradiation times are 30 times, overlap rate is 50%, working distance is 20cm. After irradiation modification under the process parameters, nano-scale fine grain structure appears on the surface of GH4169 high temperature alloy substrate, the thickness of the obtained remelting treatment layer is 8.4μm, the surface is smooth and uniform, the roughness is only Ra≈0.5μm, and the molten pit structure disappears;

[0061] (3) The NiCoCrAlY (Cr 23wt%, Al 13wt%, Y0.5wt%, Co 25wt%, Ni Bal.) coating was vapor deposited on the GH4169 high-temperature alloy substrate after the irradiation modification by the AIP process. The specific process parameters were as follows: substrate heating temperature was 200°C, target-substrate distance was 140 mm, vacuum was drawn to 5×10 -3 Argon gas is introduced after Pa, and Ar atoms are ionized at high temperature and with an external bias voltage of -1000V to obtain Ar + , the substrate surface was bombarded for 1 hour under the action of electromagnetic field to remove dirt and impurities, the arc current was 75A, the arc voltage was 20V, the substrate bias was -100V, the duty cycle was 60%, and the NiCoCrAlY coating thickness was 35μm. After vapor deposition under the process parameters, a NiCoCrAlY coating with high bonding strength was formed on the surface of the GH4169 high-temperature alloy substrate;

[0062] (4) The GH4169 high temperature alloy substrate with the NiAl coating deposited thereon is subjected to vacuum heat treatment by a heat treatment process. The specific process parameters are: vacuum degree of 10 -3 Pa, heating temperature is 900℃, holding time is 4h, heating rate is 7℃ / min. After vacuum heat treatment under this process parameter, the internal stress generated in the preparation process is reduced or eliminated, element diffusion is promoted, and the interface bonding strength is further increased.

[0063] In the above embodiment, the surface of the GH4169 high-temperature alloy substrate modified by HCPEB irradiation is defect-free, and a large number of nano-scale grains and rich crystal defects and deformation structures are produced; the surface roughness of the NiCoCrAlY coating deposited on the surface of the GH4169 high-temperature alloy modified by HCPEB is reduced from the original Ra≈9.85μm to 2.67μm. In addition, compared with the NiCoCrAlY coating deposited on the surface of the original GH4169 high-temperature alloy substrate, the bonding strength of the former is significantly improved, and the average critical load is increased from the original 95N to 178N.

[0064] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×

[0065] 10 -3 Pa, irradiation voltage is 15KeV, energy density is 8J / cm 2 , pulse width time is 1.5μs, number of irradiation times is 15 times, overlap rate is 50%, working distance is 20cm. After irradiation modification under the process parameters, no obvious ultrafine grain structure is found on the surface of GH4169 high temperature alloy substrate, and the thickness of the remelting treatment layer is about 2.2μm. At the same time, there are a large number of eruption crater-like molten pits and ripple-state molten structures on the surface of the material, which increases the surface roughness of the material to Ra≈4.1μm;

[0066] In step (2) of the above embodiment, if the process parameters are specifically selected as follows: the vacuum degree is 5.5×10 -3 Pa, irradiation voltage is 50KeV, energy density is 25J / cm 2 , pulse width time is 1.5μs, number of irradiation is 40 times, overlap rate is 50%, working distance is 20cm. After irradiation modification under this process parameter condition, the thickness of the remelting layer of the GH4169 high-temperature alloy substrate does not increase significantly, but is only 8.7μm. In addition, due to heat accumulation on the surface of the material under high energy density, the grains also grow and coarsen. Under this parameter, the surface roughness of the material is again increased to Ra≈7.8μm.

[0067] From the above comparison, it can be seen that the surface characteristics of the GH4169 high-temperature alloy substrate are quite different after irradiation modification under different process parameters. Only by controlling the process parameters so that its macroscopic surface is completely polished and remelted, the roughness is reduced to Ra≤1μm, and there are no organizational defects in the microstructure, a dense remelted layer is produced, and nano-scale grains and slip structures are enriched, can the subsequent vapor deposition coating growth be improved, thereby obtaining a higher coating interface bonding strength.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for forming a high bonding strength coating on an alloy surface, characterized in that: include: After the alloy surface is irradiated by high-current pulsed electron beam technology, a dense remelted layer, a roughness as low as Ra≤1μm, and a high-energy state structure with rich slip and ultrafine grains are formed on the alloy surface; then the alloy surface is vapor deposited by vapor deposition technology, and a high bonding strength coating is formed on the alloy surface.

2. The method for forming a high bonding strength coating on the alloy surface according to claim 1, characterized in that: The alloy is at least one of DZ125 alloy, YG6 hard alloy or GH4169 high temperature alloy.

3. The method for forming a high bonding strength coating on the alloy surface according to claim 1 or 2, characterized in that: The parameters of the high-current pulse electron beam process include: vacuum degree ≤ 5.5×10 -3 Pa, irradiation voltage is 27-30KeV, energy density is 7-15J / cm 2 , pulse width time is 1-1.5μs, irradiation times are 25-35 times, overlap rate is 50-60%, and working distance is 20-30cm.

4. The method for forming a high bonding strength coating on an alloy surface according to claim 3, characterized in that: When the alloy is DZ125 alloy, the parameters of the high-current pulse electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, irradiation times is 25 times, overlap rate is 50%, working distance is 30cm; When the alloy is YG6 cemented carbide, the parameters of the high-current pulse electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 30KeV, energy density is 7J / cm 2 , pulse width time is 1μs, irradiation times is 35 times, overlap rate is 60%, working distance is 25cm; When the alloy is GH4169 high temperature alloy, the parameters of the high current pulse electron beam irradiation process include: vacuum degree of 5.5×10 -3 Pa, irradiation voltage is 27KeV, energy density is 15J / cm 2 , pulse width time is 1.5μs, irradiation times is 30 times, overlap rate is 50%, and working distance is 20cm.

5. The method for forming a high bonding strength coating on an alloy surface according to any one of claims 1 to 4, characterized in that: The vapor deposition process includes an electron beam physical vapor deposition process, an arc ion plating process, a magnetron sputtering deposition process or a chemical vapor deposition process.

6. The method for forming a high bonding strength coating on an alloy surface according to any one of claims 1 to 5, characterized in that: The coating includes a NiAl coating, a TiCN coating or a NiCoCrAlY coating.

7. The method for forming a high bonding strength coating on an alloy surface according to claim 6, characterized in that: The NiAl coating is formed by electron beam physical vapor deposition process, and the process parameters include: substrate heating temperature is 850°C, evaporation chamber vacuum degree is 10 -3 Pa, the electron beam current is 1.5A, the workpiece turret speed is 15r / min, and the deposition rate is 2.5μm / min; The TiCN coating is formed by chemical vapor deposition process, and the process parameters include: substrate heating temperature is 885°C, pressure is 60kPa, carrier gas is H2, C and N sources are CH3CN, Ti source is TiCl4, and the gas ratio of TiCl4 to CH3CN is 2:1; The NiCoCrAlY coating is formed by arc ion plating process, and the process parameters include: arc current of 75A, arc voltage of 20V, substrate bias of -100V, and duty cycle of 60%.

8. The method for forming a high bonding strength coating on an alloy surface according to any one of claims 1 to 7, characterized in that: The alloy surface is also pre-grinded and cleaned before being irradiated.

9. The method for forming a high bonding strength coating on an alloy surface according to any one of claims 1 to 8, characterized in that: After the alloy surface is subjected to vapor deposition, the high bonding strength coating is subjected to vacuum heat treatment; The process parameters of the vacuum heat treatment include: vacuum degree ≤10 -3 Pa, heating temperature is 900-1050℃, and holding time is 4-5h.

10. An alloy having a high bonding strength coating, characterized in that: The invention is prepared by the method according to any one of claims 1 to 9.

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