A kind of AlFe x Surface ceramicization method of CrCoNi high entropy alloy

Abstract

The present invention discloses an AlFe x CrCoNi high entropy alloy surface ceramicization method, AlFe x CrCoNi high entropy alloy was pretreated; a DC pulsed micro-arc oxidation power supply and a prepared silicate micro-arc oxidation electrolyte were used to pre-treat the AlFe x CrCoNi high entropy alloy was treated by micro-arc oxidation to obtain x A ceramic layer is formed on the surface of the CrCoNi high entropy alloy; the present invention uses AlFe x With the goal of ceramicizing the surface of CrCoNi high-entropy alloy, by regulating the matching degree of high-entropy alloy elements, combining the electrical parameters of high frequency, low duty cycle and high voltage, and selecting a suitable micro-arc oxidation electrolyte, a black oxide film ceramic layer can be quickly obtained on the surface of AlFexCrCoNi high-entropy alloy, realizing the ceramicization of the high-entropy alloy and improving its corrosion resistance and wear resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of high entropy alloy surface coatings, and particularly relates to an AlFe x Surface ceramicization method of CrCoNi high entropy alloy. Background Art

[0002] High-entropy alloy is also a new type of metal material developed in recent years. It is a single-phase solid solution formed by mixing five or more elements in an equiatomic ratio or a nearly equiatomic ratio. It has the advantages of high strength and hardness, good toughness, as well as excellent thermal stability and high-temperature mechanical properties.

[0003] AlFeCrCoNi high-entropy alloys are a well-researched alloy system. Their microstructure consists of a single-phase BCC solid solution with a dendritic morphology. They exhibit excellent corrosion resistance, compressive strength, and wear resistance in NaCl solutions. To further enhance the performance of high-entropy alloys, preparing suitable coatings on their surfaces is an effective approach.

[0004] Micro-arc oxidation (MAO) is a commonly used coating preparation method. It is simple, environmentally friendly, and forms a ceramic oxide film on the substrate surface, effectively improving the properties of the alloy substrate. However, the growth mechanism of MAO ceramic layers requires the substrate to be a valve metal. In the AlFeCrCoNi high-entropy alloy, Fe is not a valve metal, making MAO difficult to ceramicize. Summary of the Invention

[0005] The purpose of the present invention is to provide an AlFe x The invention discloses a surface ceramicization method for a CrCoNi high entropy alloy, which realizes the surface ceramicization of the high entropy alloy by reducing the iron content in the high entropy alloy and adjusting the micro-arc oxidation parameters to quickly establish an oxide film.

[0006] The present invention adopts the following technical solutions: an AlFe x A method for ceramicizing the surface of a CrCoNi high-entropy alloy comprises the following steps:

[0007] AlFe x CrCoNi high entropy alloy is pretreated; wherein, 0.3≤X≤0.7;

[0008] Using DC pulse micro-arc oxidation power supply and prepared silicate micro-arc oxidation electrolyte, the pre-treated AlFe x CrCoNi high entropy alloy is used as anode, and the pretreated AlFe x The CrCoNi high entropy alloy is subjected to micro-arc oxidation treatment to form a ceramic layer on its surface;

[0009] The electrical parameters of the micro-arc oxidation treatment are: single pulse output voltage of 550-650V, frequency of 800Hz-1500Hz, duty cycle of 3-6%, and oxidation time of 5-45min.

[0010] Furthermore, 0.3≤X≤0.5.

[0011] Furthermore, X=0.3.

[0012] Furthermore, AlFe x The preparation method of CrCoNi high entropy alloy is:

[0013] Select the elemental metals Al, Fe, Cr, Co and Ni with purity greater than 99.9% for use;

[0014] Heat B2O3 or boric acid with elemental metals Al, Fe, Cr, Co or Ni respectively;

[0015] The heated elemental metals Al, Fe, Cr, Co and Ni are sequentially cleaned and dried;

[0016] The dried metal elements are placed into the smelting furnace in the order of melting point to obtain AlFe x CrCoNi high entropy alloy.

[0017] Further, smelting includes:

[0018] Evacuate the furnace to a vacuum degree of 3.0×10 -3 Mpa;

[0019] Inert gas is introduced into the furnace chamber until the vacuum degree in the furnace chamber reaches -0.05 MPa;

[0020] Maintaining vacuum, using 250A melting current and 10A electromagnetic stirring current to perform forward and reverse repeated melting to obtain AlFe x CrCoNi high entropy alloy.

[0021] Furthermore, the silicate micro-arc oxidation electrolyte consists of solid analytically pure sodium silicate, sodium hydroxide, sodium metaaluminate, potassium titanium oxalate and deionized water;

[0022] The concentration of solid analytically pure sodium silicate in the electrolyte is 50 g / L, the concentration of sodium hydroxide is 0.5 g / L, the concentration of sodium metaaluminate is 5 g / L, and the concentration of potassium titanium oxalate is 10 g / L.

[0023] Furthermore, the thickness of the ceramic layer is 5 to 30 μm.

[0024] The beneficial effects of the present invention are:x The goal is to ceramicize the surface of CrCoNi high entropy alloy. By adjusting the matching degree of high entropy alloy elements, combining the electrical parameters of high frequency, low duty cycle and high voltage, and selecting the appropriate micro-arc oxidation electrolyte, it is possible to x A black oxide film ceramic layer is quickly formed on the surface of the CrCoNi high-entropy alloy, realizing the ceramicization of the high-entropy alloy and improving its corrosion resistance and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a microscopic SEM image of the black ceramic layer on the surface of the high entropy alloy of the embodiment of the present invention.

[0026] Figure 2 This is a wear curve diagram of the high entropy alloy of the embodiment of the present invention before and after micro-arc oxidation treatment DETAILED DESCRIPTION

[0027] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The present invention discloses an AlFe x The method for ceramicizing the surface of a CrCoNi high entropy alloy specifically comprises the following steps:

[0029] AlFe x CrCoNi high entropy alloy is pretreated. Specifically, the pretreatment can be degreasing and degreasing, then grinding with different water sandpapers, and finally polishing and washing. Among them, 0.3≤X≤0.7; DC pulse micro-arc oxidation power supply and prepared silicate micro-arc oxidation electrolyte are used to pre-treat AlFe x CrCoNi high entropy alloy is used as anode, and the pretreated AlFe x CrCoNi high entropy alloy was treated by micro-arc oxidation to x A ceramic layer is formed on the surface of the CrCoNi high-entropy alloy; the electrical parameters of the micro-arc oxidation treatment are: a single pulse output voltage of 550 to 650 V, a frequency of 800 Hz to 1500 Hz, a duty cycle of 3 to 6%, and an oxidation time of 5 to 45 minutes. By controlling the time of the micro-arc oxidation, on the one hand, the thickness of the film layer can be controlled, and on the other hand, the roughness of the formed film layer can be controlled, thereby improving the wear resistance of the film layer.

[0030] The present invention uses AlFe x With the goal of ceramicizing the surface of CrCoNi high-entropy alloy, by regulating the matching degree of high-entropy alloy elements, combining the electrical parameters of high frequency, low duty cycle and high voltage, and selecting a suitable micro-arc oxidation electrolyte, a black oxide film ceramic layer can be quickly obtained on the surface of AlFexCrCoNi high-entropy alloy, realizing the ceramicization of the high-entropy alloy and improving its corrosion resistance and wear resistance.

[0031] In the embodiment of the present invention, 0.3≤X≤0.5, and the optimal X=0.3.

[0032] AlFe x The preparation method of CrCoNi high entropy alloy is generally a smelting method. The smelting method of this embodiment is specifically as follows:

[0033] Select the elemental metals Al, Fe, Cr, Co and Ni with purity greater than 99.9% for use;

[0034] Heating B2O3 or boric acid with elemental metals such as Al, Fe, Cr, Co, or Ni can remove oxide films from the metal's surface, increasing the purity of the metal. When using boric acid, it decomposes to form boric anhydride, which has a melting point of 580°C. The reaction proceeds as follows: 2H2BO3 → B2O3 + 2H2O. Boric anhydride reacts with Cu, Zn, Ni, and Fe oxides to form readily soluble borates. The reaction proceeds as follows: MeO + B2O3 → MeO·B2O3. This removes oxide films from the metal's surface, with MeO representing the oxides formed by the metal's elemental components.

[0035] The heated elemental metals Al, Fe, Cr, Co and Ni are cleaned and dried in turn; the common cleaning method is ultrasonic cleaning, using alcohol as the cleaning liquid, and drying in an oven.

[0036] According to the order of melting point (low melting point metal element at the bottom, high melting point metal element at the top), the dried metal elements Al, Fe, Cr, Co and Ni are put into the smelting furnace in turn for smelting. After smelting, AlFe x CrCoNi high entropy alloy. The metal elements are placed in the order of melting point. The metal element with high melting point is pressed on the metal element with low melting point. This can effectively prevent the metal element with low melting point from volatilizing, causing uneven composition and mismatching.

[0037] Specifically, during smelting, a pure Ti ingot is first placed in a water-cooled copper crucible to absorb any residual oxygen in the furnace before smelting, ensuring a vacuum during smelting. The high-entropy alloy is then melted. The smelting furnace typically contains four crucibles, which rotate automatically to switch between the metals in each crucible.

[0038] In the specific smelting process, first vacuum is drawn to make the vacuum degree in the smelting furnace chamber reach 3.0×10 -3 Mpa and below; introduce inert gas into the furnace chamber until the vacuum degree in the furnace chamber is -0.05MPa; repeatedly evacuate and fill with argon gas for at least 3 times to reduce the air in the furnace body and keep the vacuum degree at -0.05MPa; maintain the vacuum, use 250A melting current and 10A electromagnetic stirring current to repeat forward and reverse melting to obtain AlFex CrCoNi high entropy alloy. To ensure uniform composition of the alloy, the material is repeatedly melted in forward and reverse directions many times.

[0039] The micro-arc oxidation electrolyte needs to be selected according to the specific composition of the high-entropy alloy. In the embodiment of the present invention, the silicate micro-arc oxidation electrolyte is composed of solid analytical pure sodium silicate, sodium hydroxide, sodium metaaluminate, potassium titanium oxalate and deionized water; wherein, the concentration of solid analytical pure sodium silicate in the electrolyte is 50 g / L, the concentration of sodium hydroxide is 0.5 g / L, the concentration of sodium metaaluminate is 5 g / L, and the concentration of potassium titanium oxalate is 10 g / L.

[0040] Through the above preparation process, a high entropy alloy with a ceramic layer having a thickness of 5 to 30 μm on the surface can be obtained.

[0041] The high-entropy alloy prepared by the above method has both a black decorative surface and a high-performance protective ceramic layer, which can greatly expand the application space of high-entropy alloys in decoration, military industry, optical equipment and other fields. By adjusting the Fe element in the alloy composition of the high-entropy alloy, the ceramic layer is made black. In a silicate electrolyte system, by regulating the electrical parameters of micro-arc oxidation (including voltage, frequency, duty cycle and time), the surface elements of the high-entropy alloy form their oxides in situ under the high temperature and high pressure of micro-arc oxidation discharge. The Al element generates Al2O3 during the micro-arc oxidation process, which appears white; the Cr element is oxidized to CrO3 and Cr2O3 during the micro-arc oxidation process, which appear dark purple and dark green respectively; the Co element is oxidized to CoO during the micro-arc oxidation process, which appears black-gray; in addition, under the action of high temperature and high pressure, the Fe element on the surface of the high-entropy alloy reacts with the electrolyte to generate Fe3O4. The specific reaction equation is 3Fe+4H2O(g)=Fe3O4+4H2 (high temperature conditions). Since the above-mentioned oxides are all dark colors, only Al2O3 appears white. If observed from a microscopic point of view, some differences may be observed. However, just by naked eye observation, the entire high-entropy alloy is black, and the ceramic layer thickness is 5 to 30μm.

[0042] The ceramic layer can effectively improve the hardness, wear resistance and corrosion resistance of the alloy matrix. At the same time, the porous characteristics of the ceramic layer have a more metallic texture than the traditional anodized coloring layer, which can meet the color requirements in decoration, military industry, optical equipment and other fields.

[0043] Example 1:

[0044] In this embodiment, AlFe 0.3 A black ceramic layer is prepared on the surface of the CrCoNi high entropy alloy, that is, a micro-arc oxidation ceramic layer is prepared in an electrolyte, so that a ceramic layer composed of various oxides containing Fe3O4 is uniformly formed in situ on the surface of the high entropy alloy matrix. The thickness of the ceramic layer is 5μm.

[0045] The above AlFe 0.3 The method for preparing a black ceramic layer on the surface of a CrCoNi high entropy alloy comprises the following steps:

[0046] Step 1: Select the following five elements of high purity: Al, Fe, Cr, Co, and Ni (purity is above 99.9%), and prepare them according to the chemical composition of the molar ratio of 1:0.3:1:1:1:, wherein, Al selects pure aluminum particles, and prepares 10.11g of material; Fe selects pure iron particles, and prepares 6.28g of material; Cr selects pure chromium particles, and prepares 19.49g of material; Co selects pure cobalt particles, and prepares 22.09g of material; Ni selects pure nickel particles, and prepares 22.00g of material; the prepared raw materials are heated with B2O3 to remove the oxide film on the metal surface, and then ultrasonically cleaned with alcohol for 30 minutes, dried in an oven, and set aside.

[0047] Step 2: Place the processed Al, Fe, Cr, Co, and Ni particles into a water-cooled copper crucible according to their melting points, placing the low-melting-point, volatile materials first. Once ready, close the furnace door and prepare for smelting.

[0048] The specific process is as follows: first, vacuumize the furnace so that the vacuum degree in the furnace chamber reaches 3.0×10 -3 Mpa; then fill the furnace with argon until the vacuum degree is -0.05MPa, and repeatedly evacuate and fill with argon, and repeat this process 3 times to reduce the air in the furnace body while keeping the vacuum degree at -0.05MPa; finally, smelting is carried out, using a melting current of 250A and an electromagnetic stirring current of 10A. In order to ensure the uniform composition of the alloy, the material is repeatedly melted 5 times in both directions.

[0049] Step 3: After the smelted high entropy alloy sample is degreased and polished with different water-sandpaper, and then washed with water for micro-arc oxidation treatment.

[0050] Step 4: Select chemical reagents according to the selection principle of high-entropy alloy micro-arc oxidation electrolyte to prepare a silicate-based micro-arc oxidation electrolyte. The electrolyte composition is selected as 250g of solid analytical pure sodium silicate, 2.5g of sodium hydroxide, 25g of sodium metaaluminate and 50g of potassium titanium oxalate, which are dissolved in 5L of deionized water to complete the electrolyte preparation.

[0051] Step 5: A DC pulsed micro-arc oxidation power supply was used with a single pulse output voltage of 600 V, a frequency of 800 Hz, a duty cycle of 5%, and an oxidation time of 5 minutes to form a black ceramic layer with a thickness of 5 μm on the alloy surface.

[0052] like Figure 1 As shown, it is AlFe 0.3The surface SEM image of the black micro-arc oxidation ceramic layer of CrCoNi high entropy alloy shows that 0.3 A micro-arc oxidation layer with a porous "crater" morphology is generated on the surface of the CrCoNi high-entropy alloy, and the film grows relatively uniformly, resulting in a smooth surface and increased wear resistance.

[0053] like Figure 2 Shown are AlFe before and after micro-arc oxidation treatment 0.3 The friction coefficient diagram of CrCoNi high entropy alloy shows that AlFe 0.3 The friction coefficient of CrCoNi high entropy alloy is significantly reduced to about 0.19, while that of AlFe 0.3 The friction coefficient of CrCoNi high entropy alloy is 0.65, indicating that micro-arc oxidation treatment can significantly improve the AlFe 0.3 Wear resistance of CrCoNi high entropy alloy.

[0054] Example 2:

[0055] In this embodiment, AlFe 0.5 The black ceramic layer on the surface of the CrCoNi high entropy alloy is prepared by micro-arc oxidation in an electrolyte, so that a ceramic layer composed of multiple oxides containing Fe3O4 is in situ formed on the surface of the high entropy alloy matrix. The thickness of the ceramic layer is 15μm.

[0056] The above AlFe 0.5 The method for preparing a black ceramic layer on the surface of a CrCoNi high entropy alloy comprises the following steps:

[0057] Step 1: Select high-purity Al, Fe, Cr, Co, and Ni (purity is above 99.9%) metals and prepare them according to the chemical composition of 1:0.5:1:1:1:. Among them, pure aluminum particles are selected for Al, and 9.61g of material is prepared; pure iron particles are selected for Fe, and 9.94g of material is prepared; pure chromium particles are selected for Cr, and 18.52g of material is prepared; pure cobalt particles are selected for Co, and 20.99g of material is prepared; pure nickel particles are selected for Ni, and 20.91g of material is prepared. The prepared raw materials are heated with boric acid to remove the oxide film on the metal surface, and then cleaned with alcohol ultrasonic for 30 minutes, dried in an oven, and set aside.

[0058] Step 2: Place metal particles into the water-cooled copper crucible in order of melting point, with the low-melting-point and volatile materials placed first. After preparation, close the furnace door and prepare for smelting. The specific process is: first, vacuum the furnace chamber to a vacuum degree of 3.0×10 -3Mpa; then fill the furnace with argon until the vacuum degree is -0.05MPa, and repeatedly evacuate and fill with argon, and repeat this process 3 times to reduce the air in the furnace body while keeping the vacuum degree at -0.05MPa; finally, smelting is carried out, using a melting current of 250A and an electromagnetic stirring current of 10A. In order to ensure the uniform composition of the alloy, the material is repeatedly melted 5 times in both directions.

[0059] Step 3: After the smelted high-entropy alloy sample is degreased and polished with different water-sandpaper, and then washed with water for micro-arc oxidation treatment.

[0060] Step 4: Select chemical reagents according to the selection principle of high-entropy alloy micro-arc oxidation electrolyte to prepare a silicate-based micro-arc oxidation electrolyte. The electrolyte composition is selected as 250g of solid analytical pure sodium silicate, 2.5g of sodium hydroxide, 25g of sodium metaaluminate and 50g of potassium titanium oxalate, which are dissolved in 5L of deionized water to complete the electrolyte preparation.

[0061] Step 5: A DC pulsed micro-arc oxidation power supply was used with a single pulse output voltage of 550V, a frequency of 1000Hz, a duty cycle of 3%, and an oxidation time of 20min to form a black ceramic layer with a thickness of 15μm on the alloy surface.

[0062] Example 3:

[0063] In this embodiment, AlFe 0.4 The black ceramic layer on the surface of the CrCoNi high entropy alloy is prepared by micro-arc oxidation in an electrolyte, so that a ceramic layer composed of multiple oxides containing Fe3O4 is in situ formed on the surface of the high entropy alloy matrix. The thickness of the ceramic layer is 30μm.

[0064] The above AlFe 0.4 The method for preparing a black ceramic layer on the surface of a CrCoNi high entropy alloy comprises the following steps:

[0065] Step 1: Select the following five elements of high purity: Al, Fe, Cr, Co, and Ni (purity is above 99.9%), and prepare them according to the chemical composition of 1:0.4:1:1:1:. Among them, pure aluminum particles are selected for Al, and 9.85g of material is prepared; pure iron particles are selected for Fe, and 8.16g of material is prepared; pure chromium particles are selected for Cr, and 18.99g of material is prepared; pure cobalt particles are selected for Co, and 21.53g of material is prepared; pure nickel particles are selected for Ni, and 21.44g of material is prepared. The prepared raw materials are heated with boric acid to remove the oxide film on the metal surface, and then cleaned with alcohol ultrasonic for 30 minutes, dried in an oven, and set aside.

[0066] Step 2: Place the metal particles into the water-cooled copper crucible in order of their melting points, with the low-melting-point and volatile materials placed first. After preparation, close the furnace door and prepare for smelting. The specific process is: first, vacuum the furnace chamber to a vacuum degree of 3.0×10 -3 Mpa; then fill the furnace with argon until the vacuum degree is -0.05MPa, and repeatedly evacuate and fill with argon, and repeat this process 3 times to reduce the air in the furnace body while keeping the vacuum degree at -0.05MPa; finally, smelting is carried out, using a melting current of 250A and an electromagnetic stirring current of 10A. In order to ensure the uniform composition of the alloy, the material is repeatedly melted 5 times in both directions.

[0067] Step 3: After the smelted high entropy alloy sample is degreased and polished with different water-sandpaper, and then washed with water for micro-arc oxidation treatment.

[0068] Step 4: Select chemical reagents according to the selection principle of high-entropy alloy micro-arc oxidation electrolyte to prepare a silicate-based micro-arc oxidation electrolyte. The electrolyte composition is selected as 250g of solid analytical pure sodium silicate, 2.5g of sodium hydroxide, 25g of sodium metaaluminate and 50g of potassium titanium oxalate, which are dissolved in 5L of deionized water to complete the electrolyte preparation.

[0069] Step 5: A DC pulsed micro-arc oxidation power supply was used with a single pulse output voltage of 650V, a frequency of 800Hz, a duty cycle of 6%, and an oxidation time of 45min to form a black ceramic layer with a thickness of 30μm on the alloy surface.

[0070] Example 4:

[0071] In this embodiment, AlFe 0.7 The black ceramic layer on the surface of the CrCoNi high entropy alloy is prepared by micro-arc oxidation in an electrolyte, so that a ceramic layer composed of multiple oxides containing Fe3O4 is in situ formed on the surface of the high entropy alloy matrix. The thickness of the ceramic layer is 20μm.

[0072] The above AlFe 0.7 The method for preparing a black ceramic layer on the surface of a CrCoNi high entropy alloy comprises the following steps:

[0073] Step 1: Select high-purity Al, Fe, Cr, Co, and Ni (purity is above 99.9%) metals and prepare them according to the chemical composition of 1:0.7:1:1:1:. Among them, Al selects pure aluminum particles, prepare 9.15g of material, Fe selects pure iron particles, prepare 13.26g of material, Cr selects pure chromium particles, prepare 17.64g of material, Co selects pure cobalt particles, prepare 20.00g of material, and Ni selects pure nickel particles, prepare 19.92g of material. Heat the prepared raw materials with boric acid to remove the oxide film on the metal surface, then clean them with alcohol ultrasonic for 30 minutes, dry them in an oven, and set aside.

[0074] Step 2: Place metal particles into the water-cooled copper crucible in order of melting point, with the low-melting-point and volatile materials placed first. After preparation, close the furnace door and prepare for smelting. The specific process is: first, vacuum the furnace chamber to a vacuum degree of 3.0×10 -3 Mpa; then fill the furnace with argon until the vacuum degree is -0.05MPa, and repeatedly evacuate and fill with argon, and repeat this process 3 times to reduce the air in the furnace body while keeping the vacuum degree at -0.05MPa; finally, smelting is carried out, using a melting current of 250A and an electromagnetic stirring current of 10A. In order to ensure the uniform composition of the alloy, the material is repeatedly melted 5 times in both directions.

[0075] Step 3: After the smelted high-entropy alloy sample is degreased and polished with different water-sandpaper, and then washed with water for micro-arc oxidation treatment.

[0076] Step 4: Select chemical reagents according to the selection principle of high-entropy alloy micro-arc oxidation electrolyte to prepare a silicate-based micro-arc oxidation electrolyte. The electrolyte composition is selected as 250g of solid analytical pure sodium silicate, 2.5g of sodium hydroxide, 25g of sodium metaaluminate and 50g of potassium titanium oxalate, which are dissolved in 5L of deionized water to complete the electrolyte preparation.

[0077] Step 5: Using a DC pulsed micro-arc oxidation power supply with a single pulse output voltage of 550V, a frequency of 1500Hz, a duty cycle of 3%, and an oxidation time of 20min, a black ceramic layer with a thickness of 20μm is formed on the alloy surface.

Claims

1. AlFe x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: The following steps are involved: AlFe x CrCoNi high entropy alloy is pretreated; wherein, 0.3≤X≤0.7; A DC pulse micro-arc oxidation power supply and a prepared silicate micro-arc oxidation electrolyte are used to prepare the AlFe x CrCoNi high entropy alloy is used as anode, and the pretreated AlFe x The CrCoNi high entropy alloy is subjected to micro-arc oxidation treatment to form a ceramic layer on its surface; The electrical parameters of the micro-arc oxidation treatment are: single pulse output voltage of 550-650V, frequency of 800Hz-1500Hz, duty cycle of 3-6%, and oxidation time of 5-45min; The thickness of the ceramic layer is 5 to 30 μm; The concentration of solid analytically pure sodium silicate in the electrolyte is 50 g / L.

2. An AlFe according to claim 1 x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: 0.3≤X≤0.5。 3. The AlFe according to claim 1 x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: X=0.3。 4. The AlFe according to claim 1 x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: The AlFe x The preparation method of CrCoNi high entropy alloy is: Select the elemental metals Al, Fe, Cr, Co and Ni with purity greater than 99.9% for use; Heat B2O3 or boric acid with elemental metals Al, Fe, Cr, Co or Ni respectively; The heated elemental metals Al, Fe, Cr, Co and Ni are sequentially cleaned and dried; The dried metal elements are placed into the smelting furnace in the order of melting point to obtain the AlFe x CrCoNi high entropy alloy.

5. An AlFe according to claim 4 x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: The smelting comprises: Evacuate the furnace to a vacuum degree of 3.0×10 -3 Mpa; Inert gas is introduced into the furnace chamber until the vacuum degree in the furnace chamber reaches -0.05 MPa; Maintaining vacuum, the melting current was 250 A and the electromagnetic stirring current was 10 A to perform forward and reverse repeated melting to obtain the AlFe x CrCoNi high entropy alloy.

6. An AlFe according to claim 5 x The method for ceramicizing the surface of a CrCoNi high entropy alloy is characterized in that: The silicate micro-arc oxidation electrolyte is composed of solid analytical pure sodium silicate, sodium hydroxide, sodium metaaluminate, potassium titanium oxalate and deionized water; Among them, the concentration of sodium hydroxide is 0.5 g / L, the concentration of sodium aluminate is 5 g / L, and the concentration of potassium titanium oxalate is 10 g / L.

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