Method for reactive sputtering of metal nitride diffusion coating based on plasma nitriding furnace

Abstract

The invention relates to the technical field of metal coating treatment, in particular to a method for reactive sputtering of a metal nitride diffusion coating based on a plasma nitriding furnace, which comprises the following steps of: placing a substrate to be treated in the plasma nitriding furnace, loading a high-purity tantalum target, introducing nitrogen and applying bias voltage to carry out plasma nitriding treatment; then mixed steam composed of a coating auxiliary and argon is introduced, the surface of the base body is bombarded under pulsed bias voltage, and interface strengthening is achieved; the method comprises the steps that plasma nitriding and reactive sputtering are combined, then the temperature and vacuum conditions are maintained, sputtering is started, mixed gas of a functional additive and argon is introduced synchronously, a co-deposition reaction is conducted, and finally the coating additive and the functional additive are discharged out of a furnace after being cooled to the room temperature in the vacuum environment. The synergistic effect of interface strengthening and a plating layer reinforcing phase is achieved, and the adhesive force, hardness, abrasion resistance and corrosion resistance of the plating layer are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of metal coating technology, specifically to a method for reactive sputtering of metal nitride diffusion coatings based on a plasma nitriding furnace. Background Technology

[0002] Metal nitride coatings, such as titanium nitride and tantalum nitride, formed by reactive sputtering in a plasma nitriding furnace, are widely used in the fields of machinery manufacturing, tooling, mold making, and key component manufacturing due to their high hardness, good chemical stability, and excellent wear resistance.

[0003] In the prior art, traditional reactive sputtering processes still face challenges in achieving high-performance interfacial bonding between the coating and the substrate during coating preparation. Based on this, the present invention provides a method for reactive sputtering of metal nitride diffusion coatings based on a plasma nitriding furnace. Summary of the Invention

[0004] The purpose of this invention is to provide a method for reactive sputtering of metal nitride diffusion coatings based on a plasma nitriding furnace. The composite diffusion coating prepared by this invention not only has excellent film-substrate adhesion and surface hardness, but also exhibits excellent wear resistance and corrosion resistance, effectively improving the service life and overall performance of workpieces under harsh working conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for reactive sputtering of metal nitride layers based on a plasma nitriding furnace, comprising the following steps: S1: Place the substrate to be coated in a plasma nitriding furnace, load a high-purity tantalum target into the furnace, introduce nitrogen gas, apply a bias voltage of -50 to -150V to the substrate, and perform plasma nitriding treatment. S2: After the nitriding treatment is completed, a mixed vapor consisting of coating additive and argon is introduced into the deposition chamber. At a pressure of 0.8-1.5 Pa, a pulse bias voltage of -100V to -300V is applied to the substrate and bombarded for 5-20 minutes. S3: After the bombardment is completed, maintain the cavity vacuum and the substrate temperature at 450-550℃, apply a sputtering power of 3-5W / cm² to the high-purity tantalum target, introduce nitrogen gas, introduce a gaseous mixture of functional additives and argon gas, and co-deposit for 2-4 hours. S4: After deposition, the substrate after coating is cooled to room temperature under vacuum and then removed from the furnace; The reactive sputtering metal nitride diffusion coating based on a plasma nitriding furnace comprises the following raw materials in parts by weight: 80-95 parts high-purity tantalum target, 30-50 parts argon gas, 15-25 parts nitrogen gas, 3-8 parts coating additives, and 1-3 parts functional additives. The raw materials for the coating additive include carborane, lanthanum trichloride, and tetrahydrofuran; The raw materials for the functional additives include nano-cerium dioxide, nano-silicon nitride, and surface treatment agents.

[0006] Further, the functional additive is prepared by the following method: nano-cerium dioxide powder and nano-silicon nitride powder are mixed at a mass ratio of 1:(1-1.5) to obtain a mixed powder. A surface treatment agent is added to the mixed powder, and the mixture is ground for 1-2 hours. The mixture is then calcined at 400-500℃ for 2-3 hours, cooled, ground again, and passed through an 800-1500 mesh sieve to obtain the functional additive. The mass of the surface treatment agent is 10-20% of the mass of the mixed powder.

[0007] Further, the surface treatment agent is prepared by the following method: a complexation promoter, eucalyptol, and deionized water are mixed in a mass ratio of 1.4:5:3, the pH is adjusted to 4-5 with dilute hydrochloric acid to obtain a first mixture, a silane coupling agent is added, and the mixture is stirred at 25-35°C for 0.5-1.5 h, silicon carbide micro powder is added, and the mixture is stirred at 40°C for 1-2 h to obtain a surface modifier. The silane coupling agent is KH-550 coupling agent, the mass of the silane coupling agent is 5-7% of the mass of the first mixture, and the mass of the silicon carbide micro powder is 8-12% of the mass of the first mixture.

[0008] Further, the complexing additive is prepared by the following method: molasses fermentation waste liquid is added to quicklime, allowed to stand for 1.5-2.5 hours, filtered, and the filtrate is concentrated under reduced pressure at 50-70°C to obtain a concentrated solution. Anhydrous ethanol is added, and the solution is filtered to obtain a coarse material. The coarse material is mixed with deionized water at a mass ratio of 1:9 to obtain a coarse material solution. Water-soluble polyvinylpyrrolidone is added, and the solution is stirred. Polyethylene glycol 400 is added, and the solution is stirred at 40-50°C for 25-35 minutes to obtain the complexing additive.

[0009] Furthermore, the solid-liquid ratio of quicklime to honey fermentation liquid is (3-7) g:100 mL, the volume of anhydrous ethanol is 3 times the volume of concentrated liquid, the mass of water-soluble polyvinylpyrrolidone is 1-2% of the mass of crude material solution, the K value of water-soluble polyvinylpyrrolidone is 25-30, and the mass of polyethylene glycol 400 is 0.5-1% of the mass of crude material solution.

[0010] Further, the coating aid is prepared by the following method: pretreated carborane powder is mixed with tetrahydrofuran at a mass ratio of 1:(4-9) to obtain a second mixture; lanthanum trichloride is mixed with tetrahydrofuran at a mass ratio of 1:(5.7-19) to obtain a third mixture; under a protective atmosphere, the third mixture is added dropwise to the second mixture, and the mixture is reacted at 60-80°C for 4-8 hours. After the reaction is completed, the mixture is cooled and filtered, and the filter residue is washed with tetrahydrofuran 2-3 times and dried at 50-60°C to obtain the coating aid, wherein the molar ratio of lanthanum trichloride to carborane powder is 1:(3-3.5).

[0011] Further, the pretreatment of the carborane powder includes the following steps: adding carborane, acridine salt, and ammonium hexafluorophosphate to a reaction flask at a mass ratio of 1:0.15:1.3 to obtain a mixture; adding anhydrous tetrahydrofuran to the mixture; irradiating the mixture with a green LED lamp 5 cm away from the reaction flask at 20-25℃ for 2.5-3.5 h to obtain a fourth mixture; adding deionized water; extracting with diethyl ether; collecting the extracted organic phase to obtain a fifth solution; adding anhydrous magnesium sulfate; reacting for 25-35 min; filtering; distilling the filtrate under reduced pressure; and drying at 55-65℃ for 0.5-1.5 h to obtain the pretreated carborane.

[0012] Furthermore, the mass of the anhydrous tetrahydrofuran is 35-37 times the mass of the mixture, and the mass of the deionized water is 35-36% of the mass of the fourth mixture.

[0013] Furthermore, the temperature of the coating additive evaporation zone is controlled at 180-220℃, the volume flow ratio of coating additive vapor to argon is 1:(15-25), and the functional additive is transported by the carrier gas in the form of sublimation gas at 180-250℃, with the volume flow ratio of functional additive vapor to argon being 1:(30-50).

[0014] Furthermore, the process parameters for the co-deposition process are: vacuum degree below 5.0 × 10⁻⁶. -3 Pa, working gas pressure 0.5-1.5Pa, sputtering power 3-5W / cm², substrate bias -50 to -150V, deposition temperature 450-550℃.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention introduces an interface strengthening step centered on coating additives after plasma nitriding and before reactive sputtering. By using pulsed bias plasma bombardment, active elements such as lanthanum and boron are used to perform nanoscale alloying modification on the surface of the nitrided layer, constructing a strengthening layer with a gradient transition in composition and performance. This fundamentally solves the problem of insufficient interfacial bonding in traditional sequential composite processes, and qualitatively improves the film-substrate bonding of the nitrided layer.

[0016] 2. In the reactive co-deposition stage, the present invention introduces functional additives into the plasma region in gaseous form, causing them to decompose and react in situ during the deposition process, generating a diffusely distributed nanocrystalline or amorphous reinforcing phase in the tantalum-nitrogen matrix. This in-situ reinforcement mechanism significantly refines the coating structure, effectively releasing internal stress while ensuring high hardness of the coating, and taking into account excellent toughness, wear resistance and corrosion resistance.

[0017] 3. This invention organically integrates plasma nitriding, interface strengthening, and reactive co-deposition in a plasma nitriding furnace, making the process more compact and efficient. The prepared tantalum-nitrogen-lanthanum-boron-carbon composite diffusion coating, through the synergistic effect of the nitriding layer, the strengthened interface layer, and the multifunctional composite coating, ultimately enables the workpiece surface to simultaneously possess comprehensive properties such as high load-bearing capacity, strong interface bonding, high hardness, and excellent wear and corrosion resistance, significantly extending the service life of tools, molds, and key components in complex and harsh environments. Attached Figure Description

[0018] Figure 1 The flowchart presents a method for reactive sputtering of metal nitride diffusion layers based on a plasma nitriding furnace. Detailed Implementation

[0019] Example 1

[0020] Prepare the following raw materials by weight: 80 parts high-purity tantalum target, 30 parts argon gas, 15 parts nitrogen gas, 3 parts plating additive, and 1 part functional additive.

[0021] This embodiment provides a method for reactive sputtering of metal nitride layers based on a plasma nitriding furnace, including the following steps: S1: Place the substrate to be coated in a plasma nitriding furnace, load a high-purity tantalum target into the furnace, introduce nitrogen gas, apply a bias voltage of -50V to the substrate, and perform plasma nitriding treatment. S2: After the nitriding treatment is completed, a mixed vapor consisting of coating additive and argon is introduced into the deposition chamber. At a pressure of 0.8 Pa, a pulse bias voltage of -100 V is applied to the substrate and bombarded for 5 min. S3: After the bombardment, maintain the cavity vacuum and the substrate temperature at 450℃, apply a sputtering power of 3W / cm² to the high-purity tantalum target, introduce nitrogen gas, introduce a gaseous mixture of functional additives and argon gas, and co-deposit for 2 hours. S4: After deposition, the coated substrate is cooled to room temperature under vacuum and then removed from the furnace.

[0022] The temperature of the coating additive evaporation zone is controlled at 180°C, the volume flow ratio of coating additive vapor to argon is 1:15, and the functional additive is transported by the carrier gas in the form of sublimation gas at 180°C, with a volume flow ratio of functional additive vapor to argon of 1:30.

[0023] The process parameters for the co-deposition process are: vacuum level below 5.0 × 10⁻⁶. -3 Pa, working gas pressure 0.5 Pa, sputtering power 3 W / cm², substrate bias -50 V, deposition temperature 450 °C.

[0024] Preparation of complexing additive: Take molasses fermentation waste liquid, add quicklime, let stand for 1.5 h, filter, concentrate the filtrate under reduced pressure at 50℃ to obtain concentrated liquid, add anhydrous ethanol, filter to obtain coarse material, mix the coarse material with deionized water at a mass ratio of 1:9 to obtain coarse material solution, add water-soluble polyvinylpyrrolidone, stir, add polyethylene glycol 400, stir at 40℃ for 25 min to obtain complexing additive.

[0025] Preparation of surface treatment agent: Complexation accelerator, eucalyptol and deionized water are mixed in a mass ratio of 1.4:5:3. The pH is adjusted to 4-5 with dilute hydrochloric acid to obtain a first mixture. A silane coupling agent is added and stirred at 25°C for 0.5 h. Silicon carbide micro powder is added and stirred at 40°C for 1 h to obtain a surface modifier. The silane coupling agent is KH-550 coupling agent, and the mass of the silane coupling agent is 5% of the mass of the first mixture, and the mass of the silicon carbide micro powder is 8% of the mass of the first mixture.

[0026] Preparation of functional additives: Nano-cerium dioxide powder and nano-silicon nitride powder are mixed at a mass ratio of 1:1 to obtain a mixed powder. A surface treatment agent is added to the mixed powder, and the mixture is ground for 1 hour. It is then calcined at 400℃ for 2 hours, cooled, ground again, and passed through an 800-mesh sieve to obtain the functional additives. The mass of the surface treatment agent is 10% of the mass of the mixed powder.

[0027] The solid-liquid ratio of quicklime to honey fermentation liquid is 3g:100mL, the volume of anhydrous ethanol is 3 times the volume of concentrated liquid, the mass of water-soluble polyvinylpyrrolidone is 1% of the mass of crude material solution, the K value of water-soluble polyvinylpyrrolidone is 25, and the mass of polyethylene glycol 400 is 0.5% of the mass of crude material solution.

[0028] Pretreatment of carborane powder: Carborane, acridine salt and ammonium hexafluorophosphate were added to a reaction flask at a mass ratio of 1:0.15:1.3 to obtain a mixture. Anhydrous tetrahydrofuran was added to the mixture, and the mixture was irradiated with a green LED lamp 5 cm away from the reaction flask at 20°C for 2.5 h to obtain a fourth mixture. Deionized water was added, and the mixture was extracted with diethyl ether. The organic phase obtained from the extraction was collected to obtain a fifth solution. Anhydrous magnesium sulfate was added, and the mixture was reacted for 25 min. The solution was filtered, and the filtrate was distilled under reduced pressure and dried at 55°C for 0.5 h to obtain pretreated carborane.

[0029] Preparation of coating aid: Pretreated carborane powder and tetrahydrofuran were mixed at a mass ratio of 1:4 to obtain a second mixture. Lanthanum trichloride and tetrahydrofuran were mixed at a mass ratio of 1:5.7 to obtain a third mixture. Under a protective atmosphere, the third mixture was added dropwise to the second mixture, and the reaction was carried out at 60°C for 4 hours. After the reaction was completed, the mixture was cooled and filtered. The filter residue was washed twice with tetrahydrofuran and dried at 50°C to obtain the coating aid. The molar ratio of lanthanum trichloride to carborane powder was 1:3.

[0030] The mass of anhydrous tetrahydrofuran is 35 times the mass of the mixture, and the mass of deionized water is 35% of the mass of the fourth mixture.

[0031] Example 2

[0032] Prepare the following raw materials by weight: 90 parts high-purity tantalum target, 40 parts argon gas, 20 parts nitrogen gas, 5 parts plating additives, and 2 parts functional additives.

[0033] This embodiment provides a method for reactive sputtering of metal nitride layers based on a plasma nitriding furnace, including the following steps: S1: Place the substrate to be coated in a plasma nitriding furnace, load a high-purity tantalum target into the furnace, introduce nitrogen gas, apply a bias voltage of -100V to the substrate, and perform plasma nitriding treatment. S2: After the nitriding treatment is completed, a mixed vapor consisting of coating additive and argon is introduced into the deposition chamber. At a pressure of 1.2 Pa, a pulse bias voltage of -200 V is applied to the substrate and bombarded for 15 min. S3: After the bombardment, maintain the cavity vacuum and the substrate temperature at 500℃, apply a sputtering power of 4W / cm² to the high-purity tantalum target, introduce nitrogen gas, introduce a gaseous mixture of functional additives and argon gas, and co-deposit for 3 hours. S4: After deposition, the coated substrate is cooled to room temperature under vacuum and then removed from the furnace.

[0034] The temperature of the coating additive evaporation zone is controlled at 200℃, the volume flow ratio of coating additive vapor to argon is 1:20, and the functional additive is transported by the carrier gas in the form of sublimation gas at 220℃, with a volume flow ratio of functional additive vapor to argon of 1:40.

[0035] The process parameters for the co-deposition process are: vacuum level below 5.0 × 10⁻⁶. -3 Pa, working gas pressure 1.0 Pa, sputtering power 4 W / cm², substrate bias -100 V, deposition temperature 500 °C.

[0036] Preparation of complexing additive: Take molasses fermentation waste liquid, add quicklime, let stand for 3 hours, filter, concentrate the filtrate under reduced pressure at 60℃ to obtain concentrated liquid, add anhydrous ethanol, filter to obtain coarse material, mix the coarse material with deionized water at a mass ratio of 1:9 to obtain coarse material solution, add water-soluble polyvinylpyrrolidone, stir, add polyethylene glycol 400, stir at 45℃ for 30 minutes to obtain complexing additive.

[0037] Preparation of surface treatment agent: Complexation accelerator, eucalyptol and deionized water are mixed in a mass ratio of 1.4:5:3. The pH is adjusted to 4-5 with dilute hydrochloric acid to obtain a first mixture. A silane coupling agent is added and stirred at 30°C for 1 hour. Silicon carbide micro powder is added and stirred at 40°C for 1.5 hours to obtain a surface modifier. The silane coupling agent is KH-550 coupling agent, and the mass of the silane coupling agent is 6% of the mass of the first mixture. The mass of the silicon carbide micro powder is 10% of the mass of the first mixture.

[0038] Preparation of functional additives: Nano-cerium dioxide powder and nano-silicon nitride powder are mixed at a mass ratio of 1:1.25 to obtain a mixed powder. A surface treatment agent is added to the mixed powder, and the mixture is ground for 1.5 hours. It is then calcined at 450°C for 2.5 hours, cooled, ground again, and passed through a 1200-mesh sieve to obtain the functional additives. The mass of the surface treatment agent is 15% of the mass of the mixed powder.

[0039] The solid-liquid ratio of quicklime to honey fermentation liquid is 5g:100mL, the volume of anhydrous ethanol is 3 times the volume of concentrated liquid, the mass of water-soluble polyvinylpyrrolidone is 1.5% of the mass of crude material solution, the K value of water-soluble polyvinylpyrrolidone is 25-30, and the mass of polyethylene glycol 400 is 0.75% of the mass of crude material solution.

[0040] Pretreatment of carborane powder: Carborane, acridine salt and ammonium hexafluorophosphate were added to a reaction flask at a mass ratio of 1:0.15:1.3 to obtain a mixture. Anhydrous tetrahydrofuran was added to the mixture, and the mixture was irradiated at 25°C for 3 hours with a green LED lamp 5 cm away from the reaction flask to obtain a fourth mixture. Deionized water was added, and the mixture was extracted with diethyl ether. The organic phase obtained from the extraction was collected to obtain a fifth solution. Anhydrous magnesium sulfate was added, and the mixture was reacted for 30 minutes. The solution was filtered, and the filtrate was distilled under reduced pressure and dried at 60°C for 1 hour to obtain pretreated carborane.

[0041] Preparation of coating aid: Pretreated carborane powder and tetrahydrofuran were mixed at a mass ratio of 1:6 to obtain a second mixture. Lanthanum trichloride and tetrahydrofuran were mixed at a mass ratio of 1:12 to obtain a third mixture. Under a protective atmosphere, the third mixture was added dropwise to the second mixture, and the reaction was carried out at 70°C for 6 hours. After the reaction was completed, the mixture was cooled and filtered. The filter residue was washed three times with tetrahydrofuran and dried at 55°C to obtain the coating aid. The molar ratio of lanthanum trichloride to carborane powder was 1:3.5.

[0042] The mass of anhydrous tetrahydrofuran is 36 times the mass of the mixture, and the mass of deionized water is 36% of the mass of the fourth mixture.

[0043] Example 3: Prepare the following raw materials by weight: 95 parts high-purity tantalum target, 50 parts argon gas, 25 parts nitrogen gas, 8 parts plating additives, and 3 parts functional additives.

[0044] This embodiment provides a method for reactive sputtering of metal nitride layers based on a plasma nitriding furnace, including the following steps: S1: Place the substrate to be coated in a plasma nitriding furnace, load a high-purity tantalum target into the furnace, introduce nitrogen gas, apply a bias voltage of -150V to the substrate, and perform plasma nitriding treatment. S2: After the nitriding treatment is completed, a mixed vapor consisting of coating additive and argon is introduced into the deposition chamber. At a pressure of 1.5 Pa, a pulse bias voltage of -300 V is applied to the substrate and bombarded for 20 min. S3: After the bombardment, maintain the cavity vacuum and the substrate temperature at 550℃, apply a sputtering power of 5W / cm² to the high-purity tantalum target, introduce nitrogen gas, introduce a gaseous mixture of functional additives and argon gas, and co-deposit for 4 hours. S4: After deposition, the coated substrate is cooled to room temperature under vacuum and then removed from the furnace.

[0045] The temperature of the coating additive evaporation zone is controlled at 220°C, the volume flow ratio of coating additive vapor to argon is 1:25, and the functional additive is transported by the carrier gas in the form of sublimation gas at 250°C, with a volume flow ratio of functional additive vapor to argon of 1:50.

[0046] The process parameters for the co-deposition process are: vacuum level below 5.0 × 10⁻⁶. -3 Pa, working gas pressure 1.5 Pa, sputtering power 5 W / cm², substrate bias -150 V, deposition temperature 550 °C.

[0047] Preparation of complexing additive: Take molasses fermentation waste liquid, add quicklime, let stand for 2.5 h, filter, concentrate the filtrate under reduced pressure at 70℃ to obtain concentrated liquid, add anhydrous ethanol, filter to obtain coarse material, mix the coarse material with deionized water at a mass ratio of 1:9 to obtain coarse material solution, add water-soluble polyvinylpyrrolidone, stir, add polyethylene glycol 400, stir at 50℃ for 35 min to obtain complexing additive.

[0048] Preparation of surface treatment agent: Complexation accelerator, eucalyptol and deionized water are mixed in a mass ratio of 1.4:5:3. The pH is adjusted to 4-5 with dilute hydrochloric acid to obtain a first mixture. A silane coupling agent is added and stirred at 35°C for 1.5 h. Silicon carbide micro powder is added and stirred at 40°C for 2 h to obtain a surface modifier. The silane coupling agent is KH-550 coupling agent, and the mass of the silane coupling agent is 7% of the mass of the first mixture, and the mass of the silicon carbide micro powder is 12% of the mass of the first mixture.

[0049] Preparation of functional additives: Nano-cerium dioxide powder and nano-silicon nitride powder are mixed at a mass ratio of 1:1.5 to obtain a mixed powder. A surface treatment agent is added to the mixed powder, and the mixture is ground for 2 hours. It is then calcined at 500℃ for 3 hours, cooled, ground again, and passed through a 1500-mesh sieve to obtain the functional additives. The mass of the surface treatment agent is 20% of the mass of the mixed powder.

[0050] The solid-liquid ratio of quicklime to honey fermentation liquid is 7g:100mL, the volume of anhydrous ethanol is 3 times the volume of concentrated liquid, the mass of water-soluble polyvinylpyrrolidone is 2% of the mass of crude material solution, the K value of water-soluble polyvinylpyrrolidone is 30, and the mass of polyethylene glycol 400 is 1% of the mass of crude material solution.

[0051] Pretreatment of carborane powder: Carborane, acridine salt, and ammonium hexafluorophosphate were added to a reaction flask at a mass ratio of 1:0.15:1.3 to obtain a mixture. Anhydrous tetrahydrofuran was added to the mixture, and the mixture was irradiated with a green LED lamp 5 cm away from the reaction flask at 25°C for 3.5 h to obtain a fourth mixture. Deionized water was added, and the mixture was extracted with diethyl ether. The organic phase obtained from the extraction was collected to obtain a fifth solution. Anhydrous magnesium sulfate was added, and the mixture was reacted for 35 min. The solution was filtered, and the filtrate was distilled under reduced pressure and dried at 65°C for 1.5 h to obtain pretreated carborane.

[0052] Preparation of coating aid: Pretreated carborane powder and tetrahydrofuran were mixed at a mass ratio of 1:9 to obtain a second mixture. Lanthanum trichloride and tetrahydrofuran were mixed at a mass ratio of 1:19 to obtain a third mixture. Under a protective atmosphere, the third mixture was added dropwise to the second mixture, and the reaction was carried out at 80°C for 8 hours. After the reaction was completed, the mixture was cooled and filtered. The filter residue was washed three times with tetrahydrofuran and dried at 60°C to obtain the coating aid. The molar ratio of lanthanum trichloride to carborane powder was 1:3.5.

[0053] The mass of anhydrous tetrahydrofuran is 37 times the mass of the mixture, and the mass of deionized water is 36% of the mass of the fourth mixture.

[0054] Comparative Example 1: The difference between this comparative example and Example 1 is that the coating additive was omitted.

[0055] Comparative Example 2: The difference between this comparative example and Example 1 is that the functional additives were omitted.

[0056] Comparative Example 3: The difference between this comparative example and Example 1 is that the interface enhancement step in S2 is omitted.

[0057] Comparative Example 4: The difference between this comparative example and Example 1 is that it uses conventional plasma nitriding followed by reactive sputtering deposition without adding any additives or performing interface strengthening treatment.

[0058] Performance testing: The performance of the reactive sputtered metal nitride coatings prepared in Examples 1, 2, 3, Comparative Examples 1, 2, 3, and 4 based on plasma nitriding furnaces was tested, and the test data are recorded in the table below:

[0059] In the performance test, the film-substrate adhesion test was conducted by referring to GB / T 5270-2024 "Review of Test Methods for Adhesion Strength of Electrodeposited and Chemically Deposited Metallic Coatings on Metallic Substrates", and the critical load (Lc) was measured using the scratch method.

[0060] Microhardness test: Refer to GB / T 4340.1-2024 "Metallic materials - Vickers hardness test - Part 1: Test method", and measure using a Vickers hardness tester under a 50g load.

[0061] Wear resistance test: Refer to GB / T 12444-2006 "Metallic Materials Wear Test Methods - Ring Block Test" to measure the wear amount (mg) under fixed load and rotation speed.

[0062] According to the performance test data, the diffusion coatings prepared in Examples 1, 2, and 3 are significantly better than those in Comparative Examples 1 to 4 in terms of film-substrate adhesion, microhardness, and wear resistance. This indicates that the coating additives and functional additives introduced in this invention, combined with the interface strengthening process, play a key synergistic role in enhancing the coating performance.

[0063] Specifically, in the interface strengthening step, the coating additive undergoes a nanoscale alloying reaction between its active elements, such as lanthanum and boron, and the nitriding layer on the substrate surface through high-energy pulsed plasma bombardment. This creates a strengthened interface layer with a continuous transition in composition and performance. This structure not only enhances the film-substrate adhesion by strengthening the mechanical interlocking effect, but also effectively suppresses stress concentration at the interface by alleviating the physical property mismatch between the hard coating and the relatively soft substrate. This is the fundamental reason why the adhesion of Comparative Examples 1 and 3 is significantly reduced due to the lack of coating additives or the entire interface strengthening step. Comparative Example 4, as a traditional process, completely lacks this active interface design and therefore performs the weakest. This invention solves the problem of insufficient adhesion between the hard coating and the substrate, which easily leads to early peeling, through a biomimetic gradient interface design.

[0064] Meanwhile, during the co-deposition process, the functional additives are transported in the gas phase and participate in the reaction, generating a diffusely distributed nano-reinforcing phase in situ within the tantalum-nitrogen matrix. These fine second-phase particles act as effective dislocation pinning points, significantly improving the coating's resistance to plastic deformation, manifested as a significant increase in microhardness. During wear, these hard particles form a load-bearing skeleton, effectively resisting the indentation and plowing of abrasive particles. At the same time, the dense composite structure also inhibits the initiation and propagation of microcracks, thus endowing the coating with excellent wear resistance. Comparative Example 2, lacking functional additives, has a relatively simple tantalum-nitrogen structure in its coating, thus limiting its hardness and wear resistance. Comparative Examples 1 and 3, due to weak interfacial bonding or imperfect microstructure, are more prone to micro-peeling under frictional stress, accelerating the wear failure process. This invention, by introducing an in-situ nano-reinforcing phase, achieves an optimized balance between high hardness and good toughness in the coating, significantly improving its service life.

[0065] In summary, in this invention, the plasma nitriding layer provides strong support, the interface strengthening step constructs a solid transition, and the functional additives achieve dispersion strengthening of the coating body. The comprehensive performance degradation of Comparative Example 3 demonstrates that even with the additives, the lack of the crucial interface strengthening step prevents the entire system from achieving optimal performance. This invention, through systematic process and material innovation, integrates the nitriding layer, the strengthened interface, and the composite coating into an organic whole. Not only are its performance indicators excellent, but more importantly, their synergistic effect endows the workpiece with higher reliability and durability under harsh working conditions. This ultimately solves the technical contradiction that traditional single or simple sequential composite processes cannot simultaneously achieve ultra-high bonding strength, high hardness, and high wear resistance, providing a more competitive surface strengthening solution for tools, molds, and key components.

[0066] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for reactive sputtering of metal nitride diffusion layers based on a plasma nitriding furnace, characterized in that, The method comprises the following steps: S1: placing a substrate to be plated into a plasma nitriding furnace, loading a high-purity tantalum target into the furnace, introducing nitrogen, applying a bias voltage of -50 to -150 V to the substrate, and performing plasma nitriding treatment; S2: after the nitriding treatment, introducing a mixed vapor composed of a plating aid and argon into the deposition cavity, applying a pulsed bias voltage of -100 to -300 V to the substrate under a pressure of 0.8 to 1.5 Pa, and bombarding for 5 to 20 min; S3: after the bombardment, maintaining the cavity in a vacuum state and the substrate temperature at 450 to 550 DEG C, applying a sputtering power of 3 to 5 W / cm2 to the high-purity tantalum target, introducing nitrogen, introducing a gas mixture composed of a functional aid and argon, and co-depositing and reacting for 2 to 4 h; S4: after the deposition, cooling the substrate to room temperature under a vacuum, and discharging the furnace; The reaction sputtering metal nitride plating layer based on the plasma nitriding furnace comprises the following raw materials by weight: 80 to 95 parts of a high-purity tantalum target, 30 to 50 parts of argon, 15 to 25 parts of nitrogen, 3 to 8 parts of a plating aid, and 1 to 3 parts of a functional aid. The raw materials of the plating aid include carborane, lanthanum trichloride, and tetrahydrofuran. The raw materials of the functional aid include nano cerium dioxide, nano silicon nitride, and a surface treatment agent.

2. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 1, characterized in that The functional aid is prepared by the following method: mixing nano cerium dioxide powder and nano silicon nitride powder at a mass ratio of 1: (1-1.5) to obtain mixed powder, adding a surface treatment agent to the mixed powder, grinding for 1 to 2 h, calcining at 400 to 500 DEG C for 2 to 3 h, cooling, grinding again, and sieving through a 800 to 1500 mesh sieve to obtain the functional aid, wherein the mass of the surface treatment agent is 10 to 20% of the mass of the mixed powder.

3. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 2, characterized in that The surface treatment agent is prepared by the following method: mixing a complexing promoter, eucalyptol, and deionized water at a mass ratio of 1.4:5:3, adjusting the pH to 4 to 5 with dilute hydrochloric acid to obtain a first mixed solution, adding a silane coupling agent, stirring at 25 to 35 DEG C for 0.5 to 1.5 h, and adding silicon carbide powder, stirring at 40 DEG C for 1 to 2 h to obtain the surface treatment agent, wherein the silane coupling agent is KH-550 coupling agent, the mass of the silane coupling agent is 5 to 7% of the mass of the first mixed solution, and the mass of the silicon carbide powder is 8 to 12% of the mass of the first mixed solution.

4. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 3, characterized in that The complexing additive is prepared by the following method: adding quicklime to molasses fermentation waste liquid, standing for 1.5 to 2.5 h, filtering, concentrating the filtrate under reduced pressure at 50 to 70 DEG C to obtain a concentrated solution, adding anhydrous ethanol, filtering to obtain a crude material, mixing the crude material with deionized water at a mass ratio of 1:9 to obtain a crude material solution, adding water-soluble polyvinylpyrrolidone, stirring, adding polyethylene glycol 400, and stirring at 40 to 50 DEG C for 25 to 35 min to obtain the complexing additive.

5. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 4, characterized in that The solid-liquid ratio of the quicklime and the honey sugar fermentation liquid is (3-7) g:100 mL, the volume of the anhydrous ethanol is 3 times the volume of the concentrated liquid, the mass of the water-soluble polyvinylpyrrolidine is 1-2% of the mass of the crude material solution, the K value of the water-soluble polyvinylpyrrolidine is 25-30, and the mass of the polyethylene glycol 400 is 0.5-1% of the mass of the crude material solution.

6. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 1, characterized in that The coating aid is prepared by mixing the pretreated carborane powder and tetrahydrofuran in a mass ratio of 1:(4-9) to obtain a second mixed solution, mixing lanthanum trichloride and tetrahydrofuran in a mass ratio of 1:(5.7-19) to obtain a third mixed solution, adding the third mixed solution dropwise into the second mixed solution under a protective atmosphere, and reacting at 60-80 DEG C for 4-8 h, and after the reaction is completed, cooling, filtering, washing the filter residue with tetrahydrofuran for 2-3 times, and drying at 50-60 DEG C to obtain the coating aid, wherein the molar ratio of lanthanum trichloride to carborane powder is 1:(3-3.5).

7. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 1, characterized in that The pretreatment of the carborane powder comprises the following steps: adding carborane, aziridine salt and ammonium hexafluorophosphate in a mass ratio of 1:0.15:1.3 into a reaction bottle to obtain a mixture, adding anhydrous tetrahydrofuran to the mixture, irradiating the mixture at 20-25 DEG C for 2.5-3.5 h using a green light LED lamp 5 cm away from the reaction bottle to obtain a fourth mixed solution, adding deionized water, extracting using diethyl ether, collecting the obtained organic phase to obtain a fifth solution, adding anhydrous magnesium sulfate, reacting for 25-35 min, filtering, and distilling the filtrate under reduced pressure and drying at 55-65 DEG C for 0.5-1.5 h to obtain the pretreated carborane.

8. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 7, characterized in that The mass of the anhydrous tetrahydrofuran is 35-37 times the mass of the mixture, and the mass of the deionized water is 35-36% of the mass of the fourth mixed solution.

9. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 1, characterized in that The temperature of the coating aid evaporation zone is controlled at 180-220 DEG C, the volume flow ratio of the coating aid vapor to argon is 1:(15-25), the functional aid is delivered in the form of sublimation gas at 180-250 DEG C, and the volume flow ratio of the functional aid vapor to argon is 1:(30-50).

10. The reactive sputter metal nitride diffusion coating based on a plasma nitriding furnace according to claim 1, characterized in that The process parameters of the co-deposition process are: vacuum degree less than 5.0×10 -3 Pa, working pressure 0.5-1.5 Pa, sputtering power 3-5 W / cm2, substrate bias -50 to -150 V, deposition temperature 450-550℃.

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