Method for preparing ceramic iron-nickel alloy multilayer film on metal surface

Abstract

The application discloses a method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface, which comprises the following steps: 1) preparing a multilayer film composed of a metal layer with carbide forming ability and a nickel layer on the surface of a transition metal substrate through a thin film preparation process; 2) selecting a carbon-containing iron-carbon alloy, and preparing a fine-grained iron layer on the surface of the iron-carbon alloy to obtain a carbon source material; 3) contacting the surface of the multilayer film with the surface of the iron layer of the carbon source material, and performing pressure heat treatment until a carbide layer is formed on the surface layer of the transition metal substrate; and 4) removing the carbon source material on the surface of the multilayer film, so that a ceramic / metal multilayer film is finally obtained on the surface of the transition metal, wherein the ceramic layer is composed of carbides in which iron and nickel elements are dissolved, and the metal layer is composed of an iron-nickel alloy with face-centered cubic or (and) body-centered cubic crystal structure; the multilayer film is dense and pore-free, has a high-strength interlayer interface and film-substrate interface with serrations and metallurgical bonding, and the hardness, toughness and wear resistance of the surface of the metal substrate are improved.

Description

Technical Field

[0001] This invention belongs to the technical field of surface treatment methods for metal materials, and specifically relates to a method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface. Background Technology

[0002] In recent years, with the continuous development of material surface technology, multilayer films have become ubiquitous in daily life and various fields of the national economy. Research on multilayer films has become a hot topic in the field of materials. Ceramic-metal multilayer films are layered thin films formed by alternating deposition of high-strength, high-hardness ceramic phases and high-ductility metal phases. They have excellent comprehensive mechanical properties with both strength and toughness. The mechanical properties of ceramic-metal multilayer films, such as hardness and toughness, are closely related to the bonding strength of the interlayer interface and the film-substrate interface.

[0003] Currently, multilayer films are mainly prepared by physical vapor deposition (PVD). PVD technology has advantages such as no pollution, low deposition temperature, fast film formation speed, precise control of the thickness of each film layer, and good process stability. However, multilayer films prepared by PVD have common characteristics such as overly flat interlayer interfaces and lack of metallurgical bonding, resulting in poor interfacial adhesion and limiting the comprehensive mechanical properties of multilayer films. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing ceramic iron-nickel alloy multilayer films on metal surfaces, which solves the problem of poor interlayer and substrate bonding in the existing technology for preparing multilayer films.

[0005] The technical solution adopted in this invention is a method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface, specifically including the following steps:

[0006] Step 1: Pre-treat the surface of the metal substrate, and alternately prepare the first metal layer and the second metal layer on the surface of the metal substrate using a thin film preparation process to obtain a metal substrate with multiple films;

[0007] Step 2: Select an iron-carbon alloy, grind and polish its surface, and prepare an iron layer on its surface using a thin film preparation process to obtain a carbon source material;

[0008] Step 3: The surface of the metal substrate with multilayer film described in Step 1 is brought into contact with the surface of the carbon source material, and pressure heat treatment is performed in a heat treatment furnace to obtain a metal substrate with carbon source material and ceramic-iron-nickel alloy multilayer film.

[0009] Step 4: The carbon source material is machined to a thickness of 0.01mm-1mm, and then the carbon source material is completely corroded with a chemical solution to obtain a ceramic iron-nickel alloy multilayer film on the metal surface.

[0010] The invention is further characterized by:

[0011] The surface pretreatment of the metal substrate in step 1 involves sanding the surface of the transition metal substrate with sandpaper until the contaminants and oxides on the surface of the metal substrate are removed.

[0012] In step 1, the first metal layer is one of W, Mo, Cr, Ta, Nb, Ti, Zr and V or an alloy thereof as the main chemical component, and the second metal layer is a nickel layer, in which the mass fraction of nickel element ranges from 80% to 99.9999%.

[0013] The metal matrix is ​​one of W, Mo, Cr, Ta, Nb, Ti, Zr, V and Fe or an alloy thereof as the main chemical component;

[0014] The thin film preparation process in steps 1 and 2 is physical vapor deposition, chemical vapor deposition, electroplating, and electroless plating, and any one of magnetron sputtering or ion plating can be selected;

[0015] In step 2, the thickness of the iron layer ranges from 100 nm to 3 μm, the grain size ranges from 0.01 μm to 2 μm, and the mass fraction of iron in the iron layer ranges from 95% to 99.9999%.

[0016] The carbon content in iron-carbon alloys ranges from 1.0% to 4.0% by mass.

[0017] In step 3, the pressure heat treatment involves applying uniaxial pressure to press the two surfaces together. The pressure range generated by the applied uniaxial pressure is 2-30 MPa, and the pressure heat treatment temperature range is 900℃-1200℃. During the pressure heat treatment, the multilayer film and carbon source material are in a vacuum or inert gas environment. The heat treatment ends when a carbide ceramic layer is formed on the surface of the metal substrate.

[0018] The machining in step 4 includes one of wire electrical discharge machining, machine cutting, turning, and milling; the chemical etching solution is any one of hydrochloric acid solution, sulfuric acid solution, and nitric acid solution, wherein the mass fraction of hydrochloric acid in the hydrochloric acid solution is 15%-26%, the mass fraction of sulfuric acid in the sulfuric acid solution is 39%-69%, and the mass fraction of nitric acid in the nitric acid solution is 28%-48%.

[0019] The beneficial effects of this invention are:

[0020] (1) The carbide ceramic layer in the metal surface ceramic-iron-nickel alloy multilayer film prepared by the present invention is formed by carburizing the metal, the carbide precipitates in situ, and the grain boundary bonding is strong; the carbide grows inward until it enters the interior of the substrate, and the film-substrate interface bonding is strong.

[0021] (2) Carbide ceramic layers with iron and nickel atoms dissolved in solid solution have a faster growth rate and higher density.

[0022] (3) Iron, nickel and metals with carbide-forming ability diffuse into each other, forming a high-strength interlayer interface with metallurgical bonding.

[0023] (4) The interlayer interface of the multilayer film is irregularly serrated with high roughness, which improves the interlayer bonding strength and toughness of the multilayer film.

[0024] (5) During the pressurized heat treatment, the iron element in the fine-grained iron layer on the surface of the carbon source material diffuses into the multilayer film, transforming the nickel layer into an iron-nickel alloy layer with iron as the main component. By adjusting the heat treatment temperature, the iron content of the iron-nickel alloy layer can be controlled, thereby adjusting the ratio of the phase with body-centered cubic crystal structure and the phase with face-centered cubic crystal structure in the iron-nickel alloy layer, and thus controlling the plasticity and toughness of the metal layer;

[0025] (6) Carbon has a high solid solubility in the iron-nickel alloy layer, so the iron-nickel alloy layer can promote the continuous diffusion of carbon into the matrix.

[0026] (7) The characteristic parameters of multilayer membrane structure include layered structure parameters, iron element gradient, and ceramic grain size gradient, which provide more adjustable parameters for the strengthening and toughening of multilayer membranes. It is suitable for preparing multilayer membranes with high membrane-substrate bonding strength, interlayer interface bonding strength, and both strength and toughness. Attached Figure Description

[0027] Figure 1 This is a flowchart of the method for preparing ceramic iron-nickel alloy multilayer films on metal surfaces according to the present invention;

[0028] Figure 2 This is a cross-sectional view of the WC / iron-nickel alloy multilayer film on the metal tungsten surface in Example 1 of the method for preparing ceramic iron-nickel alloy multilayer films on metal surfaces according to the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to the present invention specifically includes the following steps:

[0031] Step 1: The metal substrate is pretreated, and a first metal layer and a second metal layer are alternately prepared on the surface of the metal substrate using a thin film preparation process to form a metal substrate with multiple films. The first metal layer includes one of W, Mo, Cr, Ta, Nb, Ti, Zr and V or an alloy thereof as the main chemical component. The second metal layer is a nickel layer. The metal substrate includes one of W, Mo, Cr, Ta, Nb, Ti, Zr, V and Fe or an alloy thereof as the main chemical component. The surface of the metal substrate is polished with sandpaper to remove contaminants and oxides from the substrate surface and reduce the surface roughness of the transition metal substrate. The mass fraction of nickel in the nickel layer ranges from 80% to 99.9999%. The thin film preparation process includes one of physical vapor deposition, chemical vapor deposition, electroplating and electroless plating.

[0032] Step 2: Select an iron-carbon alloy, grind and polish its surface, and prepare an iron layer with a thickness ranging from 100 nm to 3 μm and a grain size ranging from 0.01 μm to 2 μm on its surface to obtain the carbon source material. The mass fraction of carbon in the iron-carbon alloy ranges from 1.0% to 4.0%, and the mass fraction of iron in the iron layer ranges from 95% to 99.9999%. Any feasible thin film preparation method can be used to prepare the film, including physical vapor deposition, chemical vapor deposition, electroplating, and chemical plating; preferably, magnetron sputtering and ion plating are used.

[0033] Step 3: The surface of the multilayer film obtained in Step 1 is brought into contact with the surface of the carbon source material. In the heat treatment furnace, uniaxial pressure is applied to press the two surfaces together and pressure heat treatment is performed. During the pressure heat treatment, the multilayer film and the carbon source material are in a vacuum or inert gas environment. When the first metal layer is completely transformed into a carbide ceramic layer of solid solution iron and nickel elements and a carbide ceramic layer is generated on the surface of the metal substrate, the furnace temperature of the heat treatment furnace is reduced to room temperature. Finally, a ceramic / metal multilayer film with alternating solid solution iron and nickel carbide ceramic layers and iron-nickel alloy layers is obtained on the surface of the transition metal.

[0034] The uniaxial pressure range in step 3 is 2-30 MPa, and the heat treatment temperature range is 900 degrees Celsius to 1200 degrees Celsius.

[0035] Step 4: The carbon source material on the surface of the multilayer film is removed using a combination of mechanical processing and chemical etching to obtain a metal substrate with a ceramic-iron-nickel alloy multilayer film. First, the carbon source material on the surface of the multilayer film is removed by mechanical processing until the remaining carbon source material thickness is between 0.01 mm and 1 mm. Then, the remaining carbon source material is etched away using a chemical solution.

[0036] The machining in step 4 includes one of wire electrical discharge machining, machine cutting, turning, and shaving; the chemical etching solution is any one of hydrochloric acid solution, sulfuric acid solution, and nitric acid solution, wherein the mass fraction of hydrochloric acid in the hydrochloric acid solution is 15%-26%, the mass fraction of sulfuric acid in the sulfuric acid solution is 39%-69%, and the mass fraction of nitric acid in the nitric acid solution is 28%-48%.

[0037] Finally, a ceramic-iron-nickel alloy multilayer film was obtained on the transition metal surface, with the following characteristics: the ceramic layer is composed of carbides of iron and nickel elements dissolved in solid solution, and the volume fraction of the ceramic phase is not less than 95%; the iron-nickel alloy layer is composed of iron-nickel alloy with face-centered cubic or (and) body-centered cubic crystal structure; the interlayer interface of the multilayer film is irregularly serrated and has metallurgical bonding; along the direction from the surface to the substrate, the proportion of iron element in each iron-nickel alloy layer gradually decreases, the ratio of body-centered cubic phase to face-centered cubic phase gradually decreases, and the ceramic grain size gradually increases; the surface layer of the transition metal substrate is also transformed into a carbide ceramic layer.

[0038] In the method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to the present invention, step 3 uses pressure heat treatment to transform the metal layer with carbide forming ability into a carbide ceramic layer and the nickel layer into an iron-nickel alloy layer with iron as the main component. The principle is that during the pressure heat treatment, interstitial carbon atoms in the carbon source material and iron atoms in the fine-grained iron layer on the carbon source surface diffuse into the multilayer film. At the same time, nickel atoms in the nickel layer also diffuse in the multilayer film, so that the metal layer with carbide forming ability is transformed into a carbide ceramic layer with solid solution of iron atoms and nickel atoms, and the nickel layer is transformed into an iron-nickel alloy layer with a face-centered cubic or (and) body-centered cubic crystal structure. The carburization depth should exceed the total thickness of the multilayer film in step 1, so that a carbide layer is generated on the surface of the transition metal substrate.

[0039] The crystal structure of the iron-nickel alloy layer modified by this method is affected by the iron content. When the iron mass fraction is >60 wt.%, a body-centered cubic crystal structure will be formed. When the iron mass fraction is in the range of 40 wt.%-60 wt.%, a coexisting face-centered cubic and body-centered cubic crystal structures will be formed. When the iron mass fraction is <40%, a face-centered cubic crystal structure will be formed. The crystal structure of the iron-nickel alloy layer in the multilayer film changes with the iron atom concentration gradient of the penetrating nickel layer, showing a variation of body-centered cubic crystal structure as the main structure (face-centered cubic crystal structure as the secondary structure) - coexistence of face-centered cubic and body-centered cubic crystal structures - and body-centered cubic crystal structure as the main structure (body-centered cubic crystal structure as the secondary structure).

[0040] Furthermore, due to the interdiffusion of elements at the interlayer interface and the in-situ precipitation of carbide phases, the interlayer interface of the final ceramic / metal multilayer film has metallurgical bonding and irregular serrations, which can improve the interlayer bonding force and increase toughness. As carbon atoms and iron atoms in the carbon source material diffuse toward the transition metal matrix, their concentration decreases with diffusion distance, and the size of the generated ceramic grains gradually increases with the distance from the surface.

[0041] Example 1:

[0042] Step 1: Select tungsten metal as the substrate, perform surface pretreatment on the tungsten metal substrate for which a multilayer film needs to be prepared, and alternately deposit tungsten metal layers and nickel layers on the surface of the tungsten substrate by magnetron sputtering to form a tungsten-nickel multilayer film;

[0043] Step 1.1: Polish the surface of the selected tungsten substrate with sandpaper to remove contaminants and oxides from the surface of the tungsten substrate;

[0044] Step 1.2: Place the tungsten substrate into the magnetron sputtering chamber, load the tungsten metal target and nickel target into the magnetron sputtering equipment, and alternately deposit Ni and W layers on the surface of the tungsten metal substrate. The nickel element mass fraction in the nickel layer is 99.9999%, thereby obtaining a Ni / W multilayer film with uniform layer thickness and consistent layer thickness ratio.

[0045] Step 2: Select a piece of gray cast iron HT300 with a carbon content of 3.0 wt%. Polish its surface with sandpaper to remove contaminants and oxides and reduce its surface roughness. Place the gray cast iron HT300 into a magnetron sputtering coating chamber and deposit an iron layer with a thickness of 3 μm and an average iron grain size of 2 μm on the surface of the gray cast iron HT300. The iron element mass fraction in the iron layer is 99.9999%.

[0046] Step 3: The surface of the Ni / W multilayer film obtained in Step 1 is brought into contact with the surface of the iron layer obtained in Step 2. They are placed together in a hot press furnace and a uniaxial pressure in the up and down direction is applied to press the two surfaces together. The pressure is 30 MPa. At the same time, argon gas is introduced as a protective atmosphere. The temperature is raised to 1200 degrees Celsius and held. When the carburizing depth exceeds the total thickness of the multilayer film in Step 1, and a carbide layer is generated on the surface of the tungsten metal substrate, the carburizing ends. The furnace is cooled to room temperature to obtain a WC-iron-nickel alloy multilayer film with gray cast iron HT300.

[0047] Step 4: The gray cast iron HT300 on the surface of the multilayer film is cut to a thickness of 1 mm using wire electrical discharge machining. Then, a hydrochloric acid solution is prepared and diluted with water to a 15% hydrochloric acid solution. The wire-cut material is placed in the hydrochloric acid solution until the gray cast iron HT300 is completely corroded. Finally, a multilayer film with alternating WC layers of solid solution iron and nickel atoms and iron-nickel alloy layers is obtained on the surface of the tungsten metal.

[0048] The multilayer film obtained by the above method has the following characteristics: 1) The ceramic layer is formed by tungsten carbide, with WC precipitated in situ, having a volume fraction of 99%, and is dense and non-porous, with iron and nickel atoms dissolved in the WC; 2) The original nickel layer enables the diffused iron layer to have a face-centered cubic crystal structure; 3) The interlayer interface is irregularly serrated, with high interface roughness and metallurgical bonding, and the interlayer interface bonding force of the multilayer film can reach 100N; 4) The surface hardness is about 2000HV; 5) The film-substrate interface is a WC / W interface, and the film-substrate bonding force is about 150N; 6) The surface wear resistance of the tungsten substrate is significantly improved (about 50 times higher than that of the substrate).

[0049] Example 2:

[0050] Step 1: Select molybdenum metal as the substrate, perform surface pretreatment on the molybdenum metal substrate for which a multilayer film needs to be prepared, and alternately deposit molybdenum metal layer and nickel layer on the surface of the molybdenum substrate by cathode arc ion plating to form a molybdenum / nickel multilayer film.

[0051] Step 1.1: Polish the selected molybdenum substrate surface with sandpaper to remove contaminants and oxides from the molybdenum substrate surface and reduce the surface roughness of the molybdenum substrate.

[0052] Step 1.2: Place the molybdenum substrate into the coating chamber of the cathode arc ion plating, load the molybdenum metal target and nickel target into the cathode arc ion plating equipment, and alternately deposit Ni and Mo layers on the surface of the molybdenum metal substrate. The nickel layer has a nickel element mass fraction of 80%, thereby obtaining a Ni / Mo multilayer film with uniform layer thickness and consistent layer thickness ratio.

[0053] Step 2: Select a piece of high-carbon steel T10 with a carbon content of 1.0 wt%; polish its surface with sandpaper to remove contaminants and oxides and reduce its surface roughness; place the pretreated high-carbon steel T10 into the coating chamber of the cathode arc ion plating; load the metal iron target into the cathode arc ion plating equipment; deposit an iron layer with a thickness of 100 nm and an average iron grain size of 0.01 μm on the surface of the high-carbon steel T10; the iron element mass fraction in the iron layer is in the range of 95%.

[0054] Step 3: The surface of the Ni / Mo multilayer film obtained in Step 1 is brought into contact with the surface of the iron layer obtained in Step 2. They are placed together in a hot press furnace and a uniaxial pressure in the up and down direction is applied to press the two surfaces together. The pressure is 2MPa. At the same time, argon gas is introduced as a protective atmosphere. The temperature is raised to 900 degrees Celsius and held. When the carburizing depth exceeds the total thickness of the multilayer film in Step 1, and a carbide layer is formed on the surface of the metal Mo substrate, the carburizing ends. The film is cooled to room temperature with the furnace to obtain a Mo2C-iron-nickel alloy multilayer film with high carbon steel T10.

[0055] Step 4: The high-carbon steel T10 on the surface of the multilayer film is cut to a thickness of 0.01 mm by turning. Then, a sulfuric acid solution is prepared and diluted with water to make the sulfuric acid mass fraction in the solution 65%. The wire-cut material is placed in the sulfuric acid solution until the high-carbon steel T10 is completely corroded. Finally, a multilayer film with alternating layers of Mo2C with iron and nickel atoms and iron-nickel alloy layers is obtained on the surface of the molybdenum metal.

[0056] The multilayer film obtained by the above method has the following characteristics: 1) The ceramic layer is formed by the carburization of metallic molybdenum, with Mo2C precipitated in situ. The volume fraction of Mo2C is 100%, which is dense and non-porous, and iron and nickel atoms are dissolved in Mo2C; 2) The original metallic nickel layer enables the diffusion-formed iron layer to have a body-centered cubic crystal structure; 3) The interlayer interface is irregularly serrated, with high interface roughness and metallurgical bonding. The interlayer interface bonding force of the multilayer film can reach 120N; 4) The surface hardness is about 1000HV; 5) The film-substrate interface is a Mo2C / Mo interface, and the film-substrate bonding force is about 150N; 6) The surface wear resistance of the metallic molybdenum substrate is greatly improved (about 35 times higher than that of the substrate).

[0057] Example 3:

[0058] Step 1: Select tantalum metal as the substrate, perform surface pretreatment on the tantalum metal substrate for which a multilayer film needs to be prepared, and alternately deposit tungsten and nickel layers on the surface of the tantalum substrate by cathode arc ion plating to form a tungsten / nickel multilayer film.

[0059] Step 1.1: Polish the surface of the selected tantalum substrate with sandpaper to remove contaminants and oxides from the tantalum substrate surface;

[0060] Step 1.2: Place the tantalum substrate into the coating chamber of the cathode arc ion plating, load the tungsten metal target and nickel target into the cathode arc ion plating equipment, and alternately deposit Ni and W layers on the surface of the tantalum substrate. The nickel layer has a nickel element mass fraction of 99%, thereby obtaining a Ni / W multilayer film with uniform layer thickness and consistent layer thickness ratio.

[0061] Step 2: Select a piece of ductile iron QT400-15 with a carbon content of 4.0wt%. Cut it into a size suitable for electroplating using wire cutting. Then, polish its surface with sandpaper to remove contaminants and oxides and reduce its surface roughness. Next, perform a pre-treatment process for electroplating on the ductile iron QT400-15. Prepare an electroplating iron solution, use low-carbon steel as the electroplating anode material, and use the pre-treated ductile iron QT400-15 as the electroplating cathode material. According to the operating requirements of the electroplating equipment, set parameters such as current density and electroplating time. Electroplat a layer of iron with a thickness of 100nm and an average iron grain size of 1μm on the surface of the ductile iron QT400-15. The mass fraction of iron in the iron layer is 99%.

[0062] Step 3: The surface of the Ni / W multilayer film obtained in Step 1 is brought into contact with the surface of the iron layer obtained in Step 2. They are placed together in a hot press furnace and a uniaxial pressure of 10 MPa is applied to press the two surfaces together. Argon gas is introduced as a protective atmosphere. The temperature is raised to 1050 degrees Celsius and held. When the carburizing depth exceeds the total thickness of the multilayer film in Step 1, and a carbide layer is formed on the surface of the tantalum substrate, the carburizing ends. The film is then cooled to room temperature with the furnace to obtain a WC-iron-nickel alloy multilayer film with QT400-15 cast iron.

[0063] Step 4: Using wire cutting, cut the ductile iron QT400-15 on the surface of the multilayer film to a thickness of 0.5 mm. Then, prepare a hydrochloric acid solution and dilute the saturated hydrochloric acid solution with water to make the hydrochloric acid mass fraction in the hydrochloric acid solution 26%. Place the wire-cut material in the hydrochloric acid solution until the ductile iron QT400-15 is completely corroded. Finally, a multilayer film with alternating WC layers of solid solution iron and nickel atoms and iron-nickel alloy layers is obtained on the surface of metal Ta.

[0064] The multilayer film obtained by the above method has the following characteristics: 1) The ceramic layer is formed by tungsten carbide, the substrate-side ceramic layer is formed by tantalum carbide, and the WC layer and TaC are precipitated in situ, which is dense and non-porous, and both have iron and nickel atoms dissolved in solid solution; 2) The original nickel layer enables the diffused iron layer to have body-centered cubic and face-centered cubic crystal structures; 3) The interlayer interface is irregularly serrated, with high interface roughness and metallurgical bonding, and the interlayer interface bonding force of the multilayer film can reach 140N; 4) The surface hardness is about 2200HV; 5) The film-substrate interface is a TaC / Ta interface, and the film-substrate bonding force is about 150N; 6) The surface wear resistance of the tantalum substrate is greatly improved (about 75 times higher than that of the substrate).

[0065] Example 4:

[0066] Step 1: Select niobium metal as the substrate, perform surface pretreatment on the niobium metal substrate for which multilayer films need to be prepared, and alternately deposit tantalum metal layers and nickel layers on the surface of the niobium substrate by magnetron sputtering to form a tantalum / nickel alloy multilayer film;

[0067] Step 1.1: Polish the surface of the selected niobium substrate with sandpaper to remove contaminants and oxides from the niobium substrate surface;

[0068] Step 1.2: Place the niobium substrate into the magnetron sputtering chamber, load the tantalum metal target and nickel target into the magnetron sputtering equipment, and alternately deposit Ni and Ta layers on the surface of the niobium substrate. The nickel layer has a nickel mass fraction of 90%, thereby obtaining a Ni / Ta multilayer film with uniform layer thickness and consistent layer thickness ratio.

[0069] Step 2: Select a piece of vermicular graphite cast iron RuT400 with a carbon content of 3.7%. Polish its surface with sandpaper to remove contaminants and oxides and reduce its surface roughness. Place the pretreated vermicular graphite cast iron RuT400 into the coating chamber of the cathode arc ion plating. Load the metal iron target into the cathode arc ion plating equipment to deposit an iron layer with a thickness of 500nm and an average iron grain size of 0.1μm on the surface of the vermicular graphite cast iron RuT400. The iron element mass fraction in the iron layer is 99.9%.

[0070] Step 3: The surface of the Ni / Ta multilayer film obtained in Step 1 is brought into contact with the surface of the iron layer obtained in Step 2. They are placed together in a hot press furnace and a uniaxial pressure in the up and down direction is applied to press the two surfaces together. The pressure is 20 MPa. At the same time, argon gas is introduced as a protective atmosphere. The temperature is raised to 1150 degrees Celsius and held. When the carburizing depth exceeds the total thickness of the multilayer film in Step 1, and a carbide layer is formed on the surface of the niobium substrate, the carburizing ends. The furnace is cooled to room temperature to obtain a TaC-iron-nickel alloy multilayer film with vermicular graphite cast iron RuT400.

[0071] Step 4: The vermicular graphite cast iron RuT400 on the surface of the multilayer film is cut to a thickness of 0.2 mm using wire cutting. Then, a nitric acid solution is prepared and diluted with water to make the mass fraction of nitric acid in the solution 48%. The wire-cut material is placed in the nitric acid solution until the vermicular graphite cast iron RuT400 is completely corroded. Finally, a multilayer film with alternating layers of TaC layer containing solid solution iron and nickel atoms and iron-nickel alloy layer is obtained on the surface of metallic niobium.

[0072] The multilayer film obtained by the above method has the following characteristics: 1) The ceramic layer is formed by tantalum carbide, the substrate-side ceramic layer is formed by niobium carbide, and the TaC layer and NbC are precipitated in situ, which is dense and non-porous, and both contain iron and nickel atoms in solid solution; 2) The original nickel alloy layer enables the diffusion-formed iron-nickel alloy layer to have a body-centered cubic crystal structure; 3) The interlayer interface is irregularly serrated, with high interface roughness and metallurgical bonding, and the interlayer interface bonding force of the multilayer film can reach 90N; 4) The surface hardness is about 2100HV; 5) The film-substrate interface is an NbC / Nb interface, and the film-substrate bonding force is about 140N; 6) The surface wear resistance of the niobium substrate is greatly improved (about 35 times higher than that of the substrate).

[0073] Example 5:

[0074] Step 1: Select iron-based alloy martensitic aging steel (18Ni type) as the substrate, perform surface pretreatment on the iron-based alloy substrate that needs to be prepared with a multilayer film, and alternately deposit chromium and nickel layers on the surface of the iron-based alloy substrate by cathode arc ion plating to form a chromium-nickel multilayer film.

[0075] Step 1.1: Polish the surface of the selected iron-based alloy substrate with sandpaper to remove contaminants and oxides from the substrate surface;

[0076] Step 1.2: Ni and Cr layers are alternately deposited on the surface of the iron-based alloy substrate by chemical vapor deposition. The nickel layer contains 99% nickel by mass, thereby obtaining a Ni / Cr multilayer film with uniform layer thickness and consistent layer thickness ratio.

[0077] Step 2: Select a piece of 45 steel with a carbon content of 0.5 wt.%, cut it into a size suitable for electroplating using wire cutting, and then polish its surface with sandpaper to remove contaminants and oxides and reduce its surface roughness. Then, perform a pre-treatment process for electroplating on the 45 steel, prepare an electroplating iron solution, prepare low-carbon steel as the electroplating anode material, and use the pre-treated 45 steel as the electroplating cathode material. According to the operating requirements of the electroplating equipment, electroplat a layer of iron with a thickness of 500 nm and an average iron grain size of 0.3 μm on the surface of the 45 steel, with an iron element mass fraction of 99% in the iron layer.

[0078] Step 3: The surface of the Ni / Cr multilayer film obtained in Step 1 is brought into contact with the surface of the iron layer obtained in Step 2. They are placed together in a hot press furnace and a uniaxial pressure in the up and down direction is applied to press the two surfaces together. The pressure is 15 MPa. At the same time, argon gas is introduced as a protective atmosphere. The temperature is raised to 1000 degrees Celsius and held. When the carburizing depth exceeds the total thickness of the multilayer film in Step 1, and a carbide layer is generated on the surface of the iron-based alloy martensitic aging steel, the carburizing ends. The furnace is cooled to room temperature to obtain a Cr3C2-iron-nickel alloy multilayer film with 45 steel.

[0079] Step 4: The 45 steel on the surface of the multilayer film is cut to a thickness of 1 mm using wire cutting. Then, a nitric acid solution is prepared and diluted with water to make the nitric acid mass fraction in the nitric acid solution 28%. The wire-cut material is placed in the nitric acid solution until the 45 steel is completely corroded. Finally, a multilayer film with alternating layers of Cr3C2 with solid solution iron and nickel atoms and iron-nickel alloy layers is obtained on the surface of the iron-based alloy martensitic aging steel.

[0080] The multilayer film obtained by the above method has the following characteristics: 1) The ceramic layer is formed by chromium carbide, Cr3C2 is precipitated in situ, the volume fraction of Cr3C2 is 98%, the ceramic layer is dense and non-porous, and iron and nickel atoms are dissolved in Cr3C2; 2) The original nickel layer enables the diffusion-formed iron layer to have a face-centered cubic crystal structure; 3) The interlayer interface is irregularly serrated, with high interface roughness and metallurgical bonding, and the interlayer interface bonding force of the multilayer film can reach 120N; 4) The surface hardness is about 2400HV; 5) The film-substrate interface is an Fe3C / Fe interface, and the film-substrate bonding force is about 150N; 6) The surface wear resistance of the iron-based alloy martensitic aging steel is greatly improved (about 20 times higher than the wear resistance of the substrate).

[0081] The mechanical properties of the metal-ceramic iron-nickel alloy multilayer films prepared in Examples 1-5 were tested, and the test results are shown in the table below:

[0082] project Interlayer interface bonding strength Membrane-based bonding strength Surface hardness Example 1 100N 150N 2000HV Example 2 120N 150N 1000HV Example 3 140N 150N 2200HV Example 4 90N 140N 2100HV Example 5 120N 150N 2400HV

[0083] Through the above methods, the surface hardness of the metal surface ceramic iron-nickel alloy multilayer film of the present invention reaches 1000HV-2400HV, and the mechanical properties of the metal surface ceramic iron-nickel alloy multilayer film are good; the interlayer interface bonding force exceeds 90N, the interlayer interface of the multilayer film is irregularly serrated, and the roughness is high, which improves the interlayer interface bonding strength and toughness of the multilayer film. The carbide ceramic layer is formed by carburizing the metal, the carbide precipitates in situ, the grain boundary bonding force is strong, the carbide grows inward until it enters the interior of the matrix, the film-substrate interface bonding force is strong, and the film-substrate interface bonding force exceeds 140N.

Claims

1. A method for preparing a ceramic-iron-nickel alloy multilayer film on a metal surface, characterized in that, Specifically, the following steps are included: Step 1: Pre-treat the surface of the metal substrate, and alternately prepare a first metal layer and a second metal layer on the surface of the metal substrate using a thin film preparation process to obtain a metal substrate with a multilayer film; Step 2: Select an iron-carbon alloy, grind and polish its surface, and prepare an iron layer on its surface using a thin film preparation process to obtain a carbon source material; Step 3: Contact the surface of the metal substrate with the multilayer film obtained in Step 1 with the surface of the carbon source material, and perform pressure heat treatment in a heat treatment furnace to obtain a metal substrate with a carbide ceramic-iron-nickel alloy multilayer film containing the carbon source material; Step 4: Machining the carbon source material to a thickness of 0.01mm-1mm, and then corroding the carbon source material completely with a chemical solution to obtain a carbide ceramic-iron-nickel alloy multilayer film on the metal surface; In step 1, the first metal layer is one of W, Mo, Cr, Ta, Nb, Ti, Zr and V, and the second metal layer is a nickel layer, wherein the mass fraction of nickel in the nickel layer ranges from 80% to 99.9999%.

2. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, The surface pretreatment of the metal substrate in step 1 involves sanding the surface of the metal substrate with sandpaper until contaminants and oxides on the surface of the metal substrate are removed.

3. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, The metal matrix is ​​one of W, Mo, Cr, Ta, Nb, Ti, Zr, V and Fe.

4. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, The thin film preparation process described in steps 1 and 2 is either magnetron sputtering or ion plating.

5. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, In step 2, the thickness of the iron layer ranges from 100 nm to 3 μm, the grain size ranges from 0.01 μm to 2 μm, and the mass fraction of iron in the iron layer ranges from 95% to 99.9999%.

6. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, The carbon content of the iron-carbon alloy ranges from 1.0% to 4.0% by mass.

7. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, In step 3, the pressure heat treatment involves applying uniaxial pressure to press the two surfaces together. The pressure range of the uniaxial pressure is 2-30 MPa, and the pressure heat treatment temperature range is 900℃-1200℃. During the pressure heat treatment, the multilayer film and carbon source material are in a vacuum or inert gas environment. The heat treatment ends when a carbide ceramic layer is formed on the surface of the metal substrate.

8. The method for preparing a ceramic iron-nickel alloy multilayer film on a metal surface according to claim 1, characterized in that, The machining in step 4 includes one of wire electrical discharge machining, machine cutting, turning, and milling; the chemical solution is any one of hydrochloric acid solution, sulfuric acid solution, and nitric acid solution, wherein the hydrochloric acid solution has a hydrochloric acid mass fraction of 15%-26%, the sulfuric acid solution has a sulfuric acid mass fraction of 39%-69%, and the nitric acid solution has a nitric acid mass fraction of 28%-48%.

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