A gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating and a preparation method thereof

Abstract

The present invention discloses a gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating and a preparation method thereof. After sequentially depositing a Cr film and a FeCrAlTi film on a substrate by using a method combining multi-arc ion plating and magnetron sputtering, an FeCrAlTiSi-N film is obtained by sputtering an FeCrAlTiSi target in a nitrogen atmosphere. The coating obtained by the present invention has high film-substrate bonding strength, high hardness, excellent wear resistance and corrosion resistance to liquid lead-bismuth.

Description

Technical Field

[0001] The present invention relates to a dispersion-strengthened high-entropy alloy nitride ceramic coating with a gradient structure of Fe-Cr-Al-Ti-Si and a preparation method thereof, belonging to the fields of coating materials and surface science and technology. Background Art

[0002] High-entropy ceramics generally refer to solid solutions formed by five or more ceramic components. Due to their unique "high-entropy effect" and excellent properties, they have become a hot topic in the ceramic field in recent years. The research on high-entropy ceramics can be traced back to 2015. At that time, Rost, Maria from North Carolina State University in the United States and Curtarolo from Duke University first reported a rock-salt-structured entropy-stabilized oxide ceramic, that is, high-entropy ceramics. Subsequently, more and more high-entropy ceramics, including fluorite-structured, perovskite-structured, spinel-structured high-entropy oxide ceramics and non-oxide high-entropy ceramics such as borides, carbides, nitrides, and silicides, have emerged like bamboo shoots after a spring rain and gradually become a research hotspot.

[0003] So far, the large family of high-entropy ceramics has covered carbides, nitrides, borides, silicides, sulfides, etc., and the application fields involved include high-temperature heat insulation, high-temperature heat protection, resistance to high-temperature corrosion and oxidation, superhard machining and wear-resistant coatings, biocompatible coatings, electromagnetic absorption and shielding, catalysis and cracking, supercapacitors, lithium-ion batteries, thermoelectric conversion, oxygen ion sensors, etc.

[0004] A high-entropy ceramic coating refers to depositing high-entropy ceramics on the surface of various materials or workpieces through physical or chemical methods, so as to make full use of the advantages of high-entropy ceramics and play a role in protecting the substrate. At present, the common methods for preparing high-entropy ceramic coatings mainly include spraying method and magnetron sputtering method. The spraying method for preparing coatings has a fast speed, but has a high porosity and the coating is not dense enough; the coating prepared by the magnetron sputtering method has a dense surface and good uniformity, but the bonding strength between the coating and the substrate is not high enough. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a dispersion-strengthened high-entropy alloy nitride ceramic coating with a gradient structure and a preparation method thereof, aiming to prepare a new type of Cr / Fe with a total thickness of 1-3 μm by using a composite method of multi-arc ion plating and magnetron sputtering x1 Cr y1 Al z1 Ti k1 / Fe x2 Cr y2 Al z2 Ti k2 Si r2 Np2 Coating

[0006] To achieve the purpose, the present invention adopts the following technical solutions:

[0007] A gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating, characterized in that: the coating is obtained by sequentially depositing a Cr film and an FeCrAlTi film on a substrate, and then sputtering an FeCrAlTiSi target in a nitrogen atmosphere to obtain an FeCrAlTiSi-N film.

[0008] Furthermore, the total thickness of the coating is 1-3 μm, where the thickness of the Cr film is 15-30 nm, the thickness of the FeCrAlTi film is 20-40 nm, and the balance of the total thickness is the FeCrAlTiSi-N film.

[0009] Furthermore, the elements in the FeCrAlTi film are composed according to the atomic ratio as Fe x1 Cr y1 Al z1 Ti k1 , where x1 + y1 + z1 + k1 = 100, and 5 < x1, y1, z1, k1 < 40.

[0010] Furthermore, the elements in the FeCrAlTiSi-N film are composed according to the atomic ratio as Fe x2 Cr y2 Al z2 Ti k2 Si r2 N p2 , and the structure is an FeCrAlTiN high-entropy alloy nitride dispersion-strengthened by Si3N4 ceramic particles, where x2 + y2 + z2 + k2 + r2 = 100, and 0 < x2, y2, z2, k2, r2, p2 < 50.

[0011] The preparation method of the gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating of the present invention is characterized by including the following steps:

[0012] Step 1: Load the substrate onto the sample stage;

[0013] Step 2: Install the Cr target and the Fe-Cr-Al-Ti target on the multi-arc source, and adjust the distance between the target and the substrate to 100-200 mm;

[0014] Step 3: Install the Fe-Cr-Al-Ti-Si target on the magnetron cathode, and adjust the distance between the target and the substrate to 80-100 mm;

[0015] Step 4: Turn on the machine, first evacuate to 5×10 -4 Pa, and then heat the substrate to 300-450 °C;

[0016] Step 5: Introduce argon, set the argon flow rate to 40 - 100 sccm, and control the working pressure to 0.5 - 1.0 Pa;

[0017] Step 6: Turn on the DC bias power supply, set the sputtering bias voltage to -200 V to -700 V, and sputter - clean the substrate;

[0018] Step 7: Turn on the multi - arc Cr target sputtering power supply, set the bias voltage to -50 V to -200 V, the multi - arc target sputtering current to 30 - 100 A, control the sputtering time for 1 - 10 min, and prepare the Cr thin film;

[0019] Step 8: Turn off the multi - arc Cr target sputtering power supply, turn on the multi - arc Fe - Cr - Al - Ti target sputtering power supply, set the multi - arc target sputtering current to 30 - 80 A, control the sputtering time for 1 - 20 min, and prepare the Fe - Cr - Al - Ti thin film;

[0020] Step 9: Turn off the multi - arc Fe - Cr - Al - Ti target sputtering power supply, introduce nitrogen, set the flow rate to 5 - 50 sccm, and control the working pressure to 0.5 - 1.5 Pa;

[0021] Step 10: Turn on the DC sputtering power supply of the Fe - Cr - Al - Ti - Si magnetron target, control the sputtering power to 90 - 200 W, and the sputtering time to 2 - 3 h, and prepare the FeCrAlTiSi - N thin film;

[0022] Step 11: After sputtering is completed, turn off the sputtering power supply, the heating power supply and the bias power supply, stop gas supply. The sample is cooled to below 100 °C under the condition of vacuum pumping by the molecular pump, then the molecular pump is turned off and the power supply is turned off. It is cooled to room temperature under natural vacuum, and then the sample is taken out, and a gradient - structured, Si3N4 - dispersed - strengthened FeCrAlTi - N coating (Cr / FeCrAlTi / FeCrAlTiSi - N) is formed on the substrate.

[0023] Compared with the existing technology, the beneficial effects of the present invention are as follows:

[0024] The present invention uses a method of combining multi - arc ion plating and magnetron sputtering to prepare a novel Cr / FeCrAlTi / FeCrAlTiSi - N coating, which has high film - substrate bonding strength, high hardness, excellent wear resistance and liquid lead - bismuth corrosion resistance. Description of the Drawings

[0025] Figure 1 For the Cr / Fe obtained in Example 2 29 Cr 38 Al 14 Ti 19 / Fe 17 Cr20 Al7Ti 16 Si5N 35 SEM images of the surface morphology of the coating show that the coating surface is dense, smooth, and free of large particles.

[0026] Figure 2 The nano-indentation hardness and film-substrate bonding strength of the Cr / FeCrAlTi / FeCrAlTiSi-N coatings obtained in each example.

[0027] Figure 3 The wear rate and corrosion rate of the Cr / FeCrAlTi / FeCrAlTiSi-N coatings obtained in each example. Specific embodiments

[0028] The present invention will be further described in conjunction with the following examples.

[0029] In the following examples, the equipment used to prepare the Cr / FeCrAlTi / FeCrAlTiSi-N coating is a magnetron-multi-arc composite vacuum ion plating equipment.

[0030] The target materials used in the following examples are target materials prepared by powder metallurgy method or can be purchased on the market.

[0031] The nano-indentation hardness of the coatings obtained in the following examples was tested using a nano-indentation instrument.

[0032] The film-substrate bonding strength of the coatings obtained in the following examples was obtained by combining indentation technology with scanning electron microscopy observation.

[0033] The wear rate of the coatings obtained in the following examples was obtained by a friction and wear tester.

[0034] The corrosion rate of the coatings obtained in the following examples was analyzed by a dynamic lead-bismuth corrosion tester combined with cross-sectional scanning electron microscopy

[0035] Example 1

[0036] This example provides a gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating. After depositing a Cr film and a FeCrAlTi film on a substrate in sequence, a FeCrAlTiSi-N film is obtained by sputtering a FeCrAlTiSi target in a nitrogen atmosphere. The composition of each element in the FeCrAlTi film by atomic ratio is Fe 29 Cr 38 Al 14 Ti 19 , and the composition of each element in the FeCrAlTiSi-N film by atomic ratio is Fe 18 Cr 21 Al8Ti 17 Si6N30 . The preparation steps of the coating are as follows:

[0037] Step 1: After cutting the 314L stainless steel into pieces, polish and clean it to obtain the substrate, and then load the substrate onto the sample stage.

[0038] Step 2: Install the Cr target and the Fe 30 Cr 30 Al 10 Ti 30 targets on the multi-arc source, and adjust the distance between the target and the substrate to 120 mm.

[0039] Step 3: Install the Fe 25 Cr 30 Al 12 Ti 25 Si8 target on the magnetron cathode, and adjust the distance between the target and the substrate to 100 mm.

[0040] Step 4: Turn on the machine, first evacuate the vacuum to 5×10 -4 Pa, and then heat the substrate to 400 °C.

[0041] Step 5: Introduce argon, set the argon flow rate to 60 sccm, and control the working pressure to 1.0 Pa.

[0042] Step 6: Turn on the DC bias power supply, set the sputtering bias to -700 V, and sputter and clean the substrate.

[0043] Step 7: Turn on the multi-arc Cr target sputtering power supply, set the bias to -50 V, the multi-arc target sputtering current to 40 A, control the sputtering time for 3 min, and prepare a Cr film with a thickness of 30 nm.

[0044] Step 8: Turn off the multi-arc Cr target sputtering power supply, turn on the multi-arc Fe 30 Cr 30 Al 10 Ti 30 target sputtering power supply, set the multi-arc target sputtering current to 50 A, control the sputtering time for 3 min, and prepare a Fe 29 Cr 38 Al 14 Ti 19 film.

[0045] Step 9: Turn off the multi-arc Fe-Cr-Al-Ti target sputtering power supply, introduce nitrogen, set the flow rate to 15 sccm, and control the working pressure to 0.8 Pa.

[0046] Step 10: Turn on the Fe 25 Cr 30 Al 12 Ti 25Si8 magnetron sputtering DC power supply, control the sputtering power to 120 W, sputtering time 2 h, to prepare Fe 18 Cr 21 Al8Ti 17 Si6N 30 thin film.

[0047] Step 11: After sputtering is completed, turn off the sputtering power supply, heating power supply and bias power supply, stop ventilation, let the sample cool down to below 100 °C under the condition of molecular pump vacuuming, then turn off the molecular pump and turn off the power supply; cool to room temperature under natural vacuum, and then take out the sample, that is, a Cr / Fe 29 Cr 38 Al 14 Ti 19 / Fe 18 Cr 21 Al8Ti 17 Si6N 30 coating is prepared on the substrate, and the Fe 18 Cr 21 Al8Ti 17 Si6N 30 coating is an FeCrAlTi-N face-centered cubic structure coating strengthened by amorphous Si3N4 particles dispersion, with a thickness of 1600 nm.

[0048] After testing, the film-substrate bonding strength of the coating obtained in this example is 48 MPa, the hardness is 28 GPa, the wear rate is 0.6×10 -3 mg / Nm, and the corrosion rate in liquid lead-bismuth at 500 °C is 0.45 μm / month.

[0049] Example 2

[0050] This example provides a gradient structure dispersion-strengthened high-entropy alloy nitride ceramic coating. After sequentially depositing a Cr thin film and an FeCrAlTi thin film on the substrate, an FeCrAlTiSi-N thin film is obtained by sputtering an FeCrAlTiSi target in a nitrogen atmosphere. The atomic ratio of each element in the FeCrAlTi thin film is Fe 29 Cr 38 Al 14 Ti 19 , and the atomic ratio of each element in the FeCrAlTiSi-N thin film is Fe 17 Cr 20 Al7Ti 16 Si5N 35 . The preparation steps of the coating are as follows:

[0051] Step 1: After cutting 314L stainless steel into pieces, obtain the substrate through polishing and cleaning, and load the substrate onto the sample stage.

[0052] Step 2: Install the Cr target and Fe 30 Cr 30 Al 10 Ti 30 targets on the multi-arc source, and adjust the distance between the target and the substrate to 120 mm.

[0053] Step 3: Install the Fe 25 Cr 30 Al 12 Ti 25 Si8 target on the magnetron cathode, and adjust the distance between the target and the substrate to 100 mm.

[0054] Step 4: Turn on the machine, first evacuate the vacuum to 5×10 -4 Pa, and then heat the substrate to 400 °C.

[0055] Step 5: Introduce argon, set the argon flow rate to 60 sccm, and control the working pressure to 1.0 Pa.

[0056] Step 6: Turn on the DC bias power supply, set the sputtering bias to -700 V, and sputter clean the substrate.

[0057] Step 7: Turn on the multi-arc Cr target sputtering power supply, set the bias to -100 V, the multi-arc target sputtering current to 40 A, control the sputtering time for 3 min, and prepare a Cr film with a thickness of 26 nm.

[0058] Step 8: Turn off the multi-arc Cr target sputtering power supply, turn on the multi-arc Fe 30 Cr 30 Al 10 Ti 30 target sputtering power supply, set the multi-arc target sputtering current to 50 A, control the sputtering time for 3 min, and prepare a Fe 29 Cr 38 Al 14 Ti 19 film.

[0059] Step 9: Turn off the multi-arc Fe-Cr-Al-Ti target sputtering power supply, introduce nitrogen, and set the flow rate to 20 sccm, control the working pressure to 0.8 Pa.

[0060] Step 10: Turn on the DC sputtering power supply of the Fe 25 Cr 30 Al 12 Ti 25 Si8 magnetron target, control the sputtering power to 120 W, the sputtering time to 2 h, and prepare a Fe 17 Cr 20 Al7Ti 16 Si5N 35 film.

[0061] Step 11: After sputtering is completed, turn off the sputtering power supply, heating power supply, and bias power supply, stop gas supply, cool the sample to below 100 °C under the condition of pumping vacuum by the molecular pump, then turn off the molecular pump and the power supply; cool it to room temperature under natural vacuum, and then take out the sample, thus forming a Cr / Fe 29 Cr 38 Al 14 Ti 19 / Fe 17 Cr 20 Al7Ti 16 Si5N 35 coating on the substrate, and Fe 17 Cr 20 Al7Ti 16 Si5N 35 is an FeCrAlTi-N face-centered cubic structure coating strengthened by amorphous Si3N4 particles in dispersion, with a thickness of 1450 nm.

[0062] After testing, the film-substrate bonding strength of the coating obtained in this example is 53 MPa, the hardness is 32 GPa, the wear rate is 0.4×10 -3 mg / Nm, and the corrosion rate in liquid lead-bismuth at 500 °C is 0.39 μm / month.

[0063] Example 3

[0064] This example provides a gradient structure dispersion-strengthened high-entropy alloy nitride ceramic coating. After depositing a Cr thin film and an FeCrAlTi thin film on the substrate in sequence, an FeCrAlTiSi-N thin film is obtained by sputtering an FeCrAlTiSi target in a nitrogen atmosphere. The atomic ratio of each element in the FeCrAlTi thin film is Fe 29 Cr 38 Al 14 Ti 19 , and the atomic ratio of each element in the FeCrAlTiSi-N thin film is Fe 17 Cr 20 Al6Ti 15 Si4N 38 . The preparation steps of the coating are as follows:

[0065] Step 1: After cutting 314L stainless steel into pieces, polish and clean to obtain the substrate, and load the substrate onto the sample stage.

[0066] Step 2: Install the Cr target and Fe 30 Cr 30 Al 10 Ti 30 targets on the multi-arc source, and adjust the distance between the target and the substrate to 120 mm.

[0067] Step 3: Mount the Fe 25 Cr 30 Al 12 Ti 25 Si8 target on the magnetron cathode, and adjust the distance between the target and the substrate to 100 mm.

[0068] Step 4: Turn on the machine, first evacuate to 5×10 -4 Pa, and then heat the substrate to 400 °C.

[0069] Step 5: Introduce argon, set the argon flow rate to 60 sccm, and control the working pressure to 1.0 Pa.

[0070] Step 6: Turn on the DC bias power supply, set the sputtering bias to -700 V, and sputter clean the substrate.

[0071] Step 7: Turn on the multi-arc Cr target sputtering power supply, set the bias to -200 V, the multi-arc target sputtering current to 40 A, control the sputtering time for 3 min, and prepare a Cr film with a thickness of 21 nm.

[0072] Step 8: Turn off the multi-arc Cr target sputtering power supply, turn on the multi-arc Fe 30 Cr 30 Al 10 Ti 30 target sputtering power supply, set the multi-arc target sputtering current to 50 A, control the sputtering time for 3 min, and prepare a Fe 29 Cr 38 Al 14 Ti 19 film.

[0073] Step 9: Turn off the multi-arc Fe-Cr-Al-Ti target sputtering power supply, introduce nitrogen, set the flow rate to 30 sccm, and control the working pressure to 0.8 Pa.

[0074] Step 10: Turn on the DC sputtering power supply of the Fe 25 Cr 30 Al 12 Ti 25 Si8 magnetron target, control the sputtering power to 120 W, and the sputtering time to 2 h, and prepare a Fe 17 Cr 20 Al6Ti 15 Si4N 38 film.

[0075] Step 11: After sputtering is completed, turn off the sputtering power supply, the heating power supply and the bias power supply, stop gas supply, cool the sample to below 100 °C under the condition of molecular pump evacuation, then turn off the molecular pump, and turn off the power supply; cool to room temperature under natural vacuum, and then take out the sample, that is, a Cr / Fe 29 Cr38 Al 14 Ti 19 / Fe 17 Cr 20 Al6Ti 15 Si4N 38 Coating, Fe 17 Cr 20 Al6Ti 15 Si4N 38 It is an FeCrAlTi-N face-centered cubic structure coating strengthened by dispersion of amorphous Si3N4 particles, with a thickness of 1300 nm.

[0076] After testing, the film-substrate bonding strength of the coating obtained in this example is 58 MPa, the hardness is 37 GPa, the wear rate is 0.2×10 -3 mg / Nm, and the corrosion rate in liquid lead-bismuth at 500 °C is 0.30 μm / month.

[0077] The above content is only an example and description of the structure of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods for substitution. As long as they do not deviate from the structure of the invention or exceed the scope defined by this claim book, they should fall within the protection scope of the present invention.

Claims

1. A gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating, characterized in that: The coating is obtained by sequentially depositing a Cr film and a FeCrAlTi film on a substrate, and then sputtering a FeCrAlTiSi target in a nitrogen atmosphere to obtain a FeCrAlTiSi-N film; The composition of each element in the FeCrAlTi thin film by atomic ratio is Fe x1 Cr y1 Al z1 Ti k1 , where x1 + y1 + z1 + k1 = 100, and 5 < x1, y1, z1, k1 < 40; In the FeCrAlTiSi-N thin film, the composition of each element according to the atomic ratio is Fe x2 Cr y2 Al z2 Ti k2 Si r2 N p2 , and the structure is FeCrAlTiN strengthened by dispersion of Si3N4 ceramic particles, that is, ceramic nitride strengthened by dispersion of ceramic particles, where x2 + y2 + z2 + k2 + r2 + p2 = 100, 0 < x2, y2, z2, k2, r2, p2 < 50.

2. The gradient structure dispersion-strengthened high-entropy alloy nitride ceramic coating according to claim 1, wherein: The total thickness of the coating is 1 - 3 μm.

3. The gradient structure dispersion-strengthened high-entropy alloy nitride ceramic coating according to claim 2, wherein: The thickness of the Cr film is 15 - 30 nm, the thickness of the FeCrAlTi film is 20 - 40 nm, and the balance of the total thickness is the FeCrAlTiSi-N film.

4. A method for preparing a dispersion-strengthened high-entropy alloy nitride ceramic coating with the gradient structure according to any one of claims 1 to 3, characterized in that, It includes the following steps: Step 1: Load the substrate onto the sample stage; Step 2: Install the Cr target and the Fe-Cr-Al-Ti target on the multi-arc source, and adjust the distance between the target and the substrate to 100 - 200 mm; Step 3: Install the Fe-Cr-Al-Ti-Si target on the magnetron cathode, and adjust the distance between the target and the substrate to 80 - 100 mm; Step 4: Turn on the machine, first evacuate the vacuum to 5×10 -4 Pa, and then heat the substrate to 300 - 450 °C; Step 5: Introduce argon, set the argon flow rate to 40 - 100 sccm, and control the working pressure to 0.5 - 1.0 Pa; Step 6: Turn on the DC bias power supply, set the sputtering bias to -200 V to -700 V, and sputter-clean the substrate; Step 7: Turn on the multi-arc Cr target sputtering power supply, set the bias to -50 V to -200 V, the multi-arc target sputtering current to 30 - 100 A, and control the sputtering time to 1 - 10 min to prepare the Cr film; Step 8: Turn off the multi-arc Cr target sputtering power supply, turn on the multi-arc Fe-Cr-Al-Ti target sputtering power supply, set the multi-arc target sputtering current to 30 - 80 A, and control the sputtering time to 1 - 20 min to prepare the FeCrAlTi film; Step 9: Turn off the multi-arc Fe-Cr-Al-Ti target sputtering power supply, introduce nitrogen, and set the flow rate to 5 - 50 sccm, and control the working pressure to 0.5 - 1.5 Pa; Step 10: Turn on the DC sputtering power supply of the Fe-Cr-Al-Ti-Si magnetron target, control the sputtering power to 90 - 200 W, and the sputtering time to 2 - 3 h to prepare the FeCrAlTiSi-N film; Step 11: After sputtering is completed, turn off the sputtering power supply, the heating power supply, and the bias power supply, stop gas supply, cool the sample to below 100 °C under the condition of pumping vacuum by the molecular pump, then turn off the molecular pump, and turn off the power supply; cool to room temperature under natural vacuum, and then take out the sample, that is, a gradient-structured dispersion-strengthened high-entropy alloy nitride ceramic coating Cr / FeCrAlTi / FeCrAlTiSi-N coating is formed on the substrate.

5. The preparation method according to claim 4, characterized in that: The substrate is selected from stainless steel, ceramic, or glass.

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