A high-hardness, small-diameter ball-end milling cutter coating and its preparation method

Abstract

The present invention is applicable to the technical field of tool coatings, and provides a high-hardness, micro-diameter ball-end milling cutter coating and a preparation method thereof, wherein the high-hardness, micro-diameter ball-end milling cutter coating includes at least one functional layer deposited on the micro-diameter ball-end milling cutter, and the functional layer includes the following raw materials: aluminum oxide, modified cubic boron nitride, modified silicon carbide, modified graphene, and titanium nitride. The high-hardness, micro-diameter ball-end milling cutter coating provided by the present invention can improve the hardness and other properties of the coating by adding aluminum oxide, modified cubic boron nitride, modified silicon carbide, modified graphene, and titanium nitride to the functional layer raw materials. By adding modified cubic boron nitride and fully combining it with other components, the mechanical properties such as the hardness of the coating are improved. By adding modified silicon carbide, the hardness and deposition efficiency are improved, and the formed coating is dense, has high hardness, and good wear resistance. By adding modified graphene, the hardness and wear resistance of the coating are further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tool coatings, and in particular relates to a high-hardness, small-diameter ball-end milling cutter coating and a preparation method thereof. Background Art

[0002] A ball end mill is a tool with a ball-like blade that is mounted on a milling machine and used to mill various curved surfaces and circular grooves. A ball end mill is also called an R cutter.

[0003] Mechanical processing is constantly moving towards high precision, high speed and high efficiency. Precision machining tools such as small-diameter milling cutters and micro-diameter milling cutters have emerged. They are usually made of ultra-fine grain WC-Co cemented carbide and have poor rigidity.

[0004] In order to improve the machining performance of the micro-diameter tool, one or more layers of coatings with excellent comprehensive performance can be deposited on the surface of the micro-diameter tool through vapor deposition technology, so that it has high hardness and can protect the micro-diameter tool. Summary of the Invention

[0005] The present invention provides a high-hardness and small-diameter ball-end milling cutter coating, aiming to solve the above-mentioned problems.

[0006] The present invention is achieved in this way: a high-hardness micro-diameter ball end mill coating includes at least one functional layer deposited on the micro-diameter ball end mill, the thickness of the functional layer is 1-2 μm, and the functional layer includes the following raw materials in parts by weight: 2-4 parts of aluminum oxide, 2-3 parts of modified cubic boron nitride, 1-3 parts of modified silicon carbide, 1-2 parts of modified graphene, and 1-3 parts of titanium nitride.

[0007] Preferably, the functional layer comprises the following raw materials in parts by weight: 2.5-3.5 parts of aluminum oxide, 2.2-2.8 parts of modified cubic boron nitride, 1.5-2.5 parts of modified silicon carbide, 1.3-1.7 parts of modified graphene, and 1.5-2.5 parts of titanium nitride.

[0008] Preferably, the functional layer comprises the following raw materials in parts by weight: 3 parts of aluminum oxide, 2.5 parts of modified cubic boron nitride, 3 parts of modified silicon carbide, 1.5 parts of modified graphene, and 2 parts of titanium nitride.

[0009] Preferably, the preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in 5-7 times its weight and a mass fraction of 10-30% nitric acid, heating to 80-90°C, stirring for 2-3h, centrifuging, washing and drying for use to obtain product A; dispersing product A in 6-8 times its weight of water, irradiating under N2O or N2 conditions, the ventilation time is 20-30min, the irradiation dose rate is 70-90Gy / min, the total dose is 90-100kGy, and filtering to obtain product B: dispersing product B in 4-7 times its weight and a volume fraction of 1-3% siloxane solution, heating to 80-100°C, reacting for 3-5h, filtering, and vacuum drying to obtain modified cubic boron nitride. By modifying, the dispersibility, chemical activity and strength of cubic boron nitride are improved, and it is fully combined with other components to improve the mechanical properties such as coating hardness.

[0010] Preferably, the preparation method of the modified silicon carbide is as follows: by weight, 6-10 parts of nano-silicon carbide are added to 30-40 parts of a hydrochloric acid solution with a mass fraction of 30-40%, and after sufficient stirring, centrifugation, washing, and drying are carried out in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 20-30 parts of a sodium chromate solution with a concentration of 100-200 g / L, and then 10-20 parts of glucose with a concentration of 40-50 g / L, 4-6 parts of polyethylene glycol with a concentration of 5-10 g / L, and 5-10 parts of sodium hexametaphosphate with a concentration of 20-40 g / L are added; high pressure is continuously stirred and the mixture is pumped into the mixture; The method comprises the following steps: heating the reaction mixture to 150-160° C. in an autoclave and reacting the mixture for 30-50 minutes; cooling the reaction mixture to below 90° C. after the reaction is completed, extracting the suspension, filtering, washing, and drying the suspension; and sintering the dried powder at 800-1000° C. for 3-4 hours to obtain modified silicon carbide; adding the nano-silicon carbide to a hydrochloric acid solution for pickling, using the hydrochloric acid solution to remove impurities on the surface of the nano-silicon carbide, thereby improving the purity of the nano-silicon carbide and increasing the hydroxyl content on the surface of the nano-silicon carbide powder to improve its activity; reducing the sodium chromate to form a chromium hydroxide layer wrapped on the surface of the silicon carbide, thereby improving the hardness and deposition efficiency. The formed coating is dense, has high hardness, and good wear resistance.

[0011] Preferably, the preparation method of the modified graphene is as follows: 4-6 parts of graphene oxide are dispersed in anhydrous ethanol by weight and ultrasonically vibrated to prepare a graphene oxide dispersion, then 0.5-1.5 parts of nano-Cr powder are added and ball milled for 30-50 minutes, the ball-milled liquid is stirred at a temperature of 120-160°C for 1-2 hours, and then freeze-dried at a temperature of -40 to -20°C for 3-5 hours to obtain modified graphene. The modified graphene has high hardness, good wear resistance, and excellent mechanical properties. The addition of nano-Cr powder forms a coating with strong interfacial bonding force, which can effectively adhere to the surface of the tool substrate.

[0012] The present invention also provides a method for preparing the high-hardness, small-diameter ball-end milling cutter coating, comprising the following steps:

[0013] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0014] The tool substrate is pre-treated and placed in a vacuum chamber;

[0015] Evacuate the vacuum chamber and preheat it to 350-450℃;

[0016] The tool substrate is ion cleaned and etched using existing arc-enhanced glow discharge technology, which takes 10-20 minutes.

[0017] N2 and Ar are continuously introduced into the vacuum chamber, and the tool substrate is coated with a film to form a functional layer using the existing magnetron sputtering technology;

[0018] After coating, cool for 90-120 minutes.

[0019] Preferably, the N2 flow rate is 40-60 sccm, the Ar flow rate is 80-120 sccm, and the coating time is 60-80 min.

[0020] Preferably, the pretreatment of the tool substrate comprises immersing the tool substrate in acetone for ultrasonic cleaning for 3-5 minutes, then immersing the tool substrate in ethanol for ultrasonic cleaning for 4-6 minutes, and then drying.

[0021] Preferably, the pretreatment of the tool substrate further includes, after drying, immersing the to-be-coated portion of the tool substrate below the liquid surface of a mixed liquid in a container, wherein the mixed liquid includes nano-titanium powder and Acetobacter xylinum fermentation liquid in a mass ratio of 1:20-30, culturing at 30-35°C for 36-48 hours, taking out the tool substrate, washing it 2-3 times with distilled water, and then drying it; during the fermentation process, bacterial cellulose grows, and the bacterial cellulose adsorbs the nano-titanium powder and adheres to the surface of the to-be-coated portion of the tool substrate, and is capable of adsorbing the coating material, thereby improving the adhesion tightness of the coating on the one hand, and improving the hardness of the coating on the other hand.

[0022] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0023] The high-hardness, small-diameter ball-end milling cutter coating provided by the present invention can improve the hardness and other properties of the coating by adding aluminum oxide, modified cubic boron nitride, modified silicon carbide, modified graphene, and titanium nitride to the functional layer raw materials. By adding modified cubic boron nitride and fully combining it with other components, the mechanical properties such as the hardness of the coating are improved. By adding modified silicon carbide, the hardness and deposition efficiency are improved. The formed coating is dense, has high hardness, and good wear resistance. By adding modified graphene, the coating hardness and wear resistance are further increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for preparing a high-hardness, small-diameter ball-end milling cutter coating provided in Examples 1-5 of the present invention.

[0025] Figure 2 This is a flow chart of a method for preparing a high-hardness, small-diameter ball-end milling cutter coating provided in Example 6 of the present invention. DETAILED DESCRIPTION

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0027] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments. Example 1

[0028] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 1 As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 1 μm, and the functional layer includes the following raw materials in parts by weight: 2 parts of aluminum oxide, 2 parts of modified cubic boron nitride, 1 part of modified silicon carbide, 1 part of modified graphene, and 1 part of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0029] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0030] The tool substrate was immersed in acetone for ultrasonic cleaning for 3 minutes, then immersed in ethanol for ultrasonic cleaning for 4 minutes, blown dry, and placed in a vacuum chamber;

[0031] Evacuate the vacuum chamber and preheat it to 350°C;

[0032] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology for 10 minutes.

[0033] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 40 sccm and the Ar flow rate is 80 sccm, and the tool substrate is coated with a film to form a functional layer using the existing magnetron sputtering technology, and the coating time is 60 minutes;

[0034] After coating, cool for 90 minutes.

[0035] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in nitric acid with a mass fraction of 10% by weight, heating to 80°C, stirring for 2 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in water with a weight of 6 times, irradiating under N2O or N2 conditions, the ventilation time is 20 minutes, the irradiation dose rate is 70Gy / min, the total dose is 90kGy, and filtering to obtain product B: dispersing product B in a siloxane solution with a volume fraction of 1% by weight by 4 times, heating to 80°C, reacting for 3 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0036] In this embodiment, the preparation method of the modified silicon carbide is as follows: 6 parts by weight of nano-silicon carbide are added to 30 parts by weight of a hydrochloric acid solution with a mass fraction of 30%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 20 parts of a sodium chromate solution with a concentration of 100 g / L, and then 10 parts of glucose with a concentration of 40 g / L, 4 parts of polyethylene glycol with a concentration of 5 g / L, and 5 parts of sodium hexametaphosphate with a concentration of 20 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 150°C and reacted for 30 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 800°C for 3 hours to obtain modified silicon carbide.

[0037] In a specific implementation, the preparation method of the modified graphene is as follows: 4 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 0.5 parts of nano-Cr powder are added and ball milled for 30 minutes. The ball-milled liquid is stirred at a temperature of 120°C for 1 hour, and then freeze-dried at a temperature of -40°C for 3 hours to obtain modified graphene. Example 2

[0038] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 1As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 1 μm, and the functional layer includes the following raw materials in parts by weight: 2.5 parts of aluminum oxide, 2.2 parts of modified cubic boron nitride, 1.5 parts of modified silicon carbide, 1.3 parts of modified graphene, and 1.5 parts of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0039] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0040] The tool substrate was immersed in acetone for ultrasonic cleaning for 3 minutes, then immersed in ethanol for ultrasonic cleaning for 4 minutes, blown dry, and placed in a vacuum chamber;

[0041] Evacuate the vacuum chamber and preheat it to 350°C;

[0042] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology for 10 minutes.

[0043] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 40 sccm and the Ar flow rate is 80 sccm, and the tool substrate is coated with a film to form a functional layer using the existing magnetron sputtering technology, and the coating time is 60 minutes;

[0044] After coating, cool for 90 minutes.

[0045] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in nitric acid with a mass fraction of 10% by weight, heating to 80°C, stirring for 2 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in water with a weight of 6 times, irradiating under N2O or N2 conditions, the ventilation time is 20 minutes, the irradiation dose rate is 70Gy / min, the total dose is 90kGy, and filtering to obtain product B: dispersing product B in a siloxane solution with a volume fraction of 1% by weight by 4 times, heating to 80°C, reacting for 3 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0046] In this embodiment, the preparation method of the modified silicon carbide is as follows: 6 parts by weight of nano-silicon carbide are added to 30 parts by weight of a hydrochloric acid solution with a mass fraction of 30%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 20 parts of a sodium chromate solution with a concentration of 100 g / L, and then 10 parts of glucose with a concentration of 40 g / L, 4 parts of polyethylene glycol with a concentration of 5 g / L, and 5 parts of sodium hexametaphosphate with a concentration of 20 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 150°C and reacted for 30 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 800°C for 3 hours to obtain modified silicon carbide.

[0047] In a specific implementation, the preparation method of the modified graphene is as follows: 4 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 0.5 parts of nano-Cr powder are added and ball milled for 30 minutes. The ball-milled liquid is stirred at a temperature of 120°C for 1 hour, and then freeze-dried at a temperature of -40°C for 3 hours to obtain modified graphene. Example 3

[0048] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 1 As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 1.5 μm, and the functional layer includes the following raw materials in parts by weight: 3 parts of aluminum oxide, 2.5 parts of modified cubic boron nitride, 3 parts of modified silicon carbide, 1.5 parts of modified graphene, and 2 parts of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0049] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0050] The tool substrate was immersed in acetone for ultrasonic cleaning for 4 minutes, then immersed in ethanol for ultrasonic cleaning for 5 minutes, blown dry, and placed in a vacuum chamber;

[0051] Evacuate the vacuum chamber and preheat it to 400°C;

[0052] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology, which took 15 minutes.

[0053] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 50 sccm and the Ar flow rate is 100 sccm, and the tool substrate is coated with a film to form a functional layer using an existing magnetron sputtering technology, and the coating time is 70 minutes;

[0054] After coating, cool for 105 minutes.

[0055] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in nitric acid with a mass fraction of 20% by weight, heating to 85°C, stirring for 2.5 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in water with a weight of 7 times, irradiating under N2O or N2 conditions, the ventilation time is 25 minutes, the irradiation dose rate is 80Gy / min, the total dose is 95kGy, and filtering to obtain product B: dispersing product B in a siloxane solution with a volume fraction of 2% by weight by 6 times, heating to 90°C, reacting for 4 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0056] In this embodiment, the preparation method of the modified silicon carbide is as follows: 8 parts by weight of nano-silicon carbide are added to 35 parts of a hydrochloric acid solution with a mass fraction of 35%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 25 parts of a sodium chromate solution with a concentration of 150 g / L, and then 15 parts of glucose with a concentration of 45 g / L, 5 parts of polyethylene glycol with a concentration of 8 g / L, and 7 parts of sodium hexametaphosphate with a concentration of 30 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 155°C and reacted for 40 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 900°C for 3.5 hours to obtain modified silicon carbide.

[0057] In a specific implementation, the preparation method of the modified graphene is as follows: 5 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 1 part of nano-Cr powder is added and ball-milled for 40 minutes. The ball-milled liquid is stirred at a temperature of 140°C for 1.5 hours, and then freeze-dried at a temperature of -30°C for 4 hours to obtain modified graphene. Example 4

[0058] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 1 As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 2 μm, and the functional layer includes the following raw materials in parts by weight: 3.5 parts of aluminum oxide, 2.8 parts of modified cubic boron nitride, 2.5 parts of modified silicon carbide, 1.7 parts of modified graphene, and 2.5 parts of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0059] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0060] The tool substrate was immersed in acetone for ultrasonic cleaning for 5 minutes, then immersed in ethanol for ultrasonic cleaning for 6 minutes, blown dry, and placed in a vacuum chamber;

[0061] Evacuate the vacuum chamber and preheat it to 450°C;

[0062] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology for 20 minutes.

[0063] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 60 sccm and the Ar flow rate is 120 sccm, and the tool substrate is coated with a film to form a functional layer using the existing magnetron sputtering technology, and the coating time is 80 minutes;

[0064] After coating, cool for 120 minutes.

[0065] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in 7 times the weight and 30% mass fraction of nitric acid, heating to 90°C, stirring for 3 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in 8 times the weight of water, irradiating under N2O or N2 conditions, the ventilation time is 30 minutes, the irradiation dose rate is 90Gy / min, the total dose is 100kGy, and filtering to obtain product B: dispersing product B in 7 times the weight and 3% volume fraction of siloxane solution, heating to 100°C, reacting for 5 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0066] In this embodiment, the preparation method of the modified silicon carbide is as follows: 10 parts by weight of nano-silicon carbide are added to 40 parts by weight of a hydrochloric acid solution with a mass fraction of 40%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 30 parts of a sodium chromate solution with a concentration of 200 g / L, and then 20 parts of glucose with a concentration of 50 g / L, 6 parts of polyethylene glycol with a concentration of 10 g / L, and 10 parts of sodium hexametaphosphate with a concentration of 40 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 160°C and reacted for 50 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 1000°C for 4 hours to obtain modified silicon carbide.

[0067] In a specific implementation, the preparation method of the modified graphene is as follows: 6 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 1.5 parts of nano-Cr powder are added and ball milled for 50 minutes. The ball-milled liquid is stirred at a temperature of 160°C for 2 hours, and then freeze-dried at a temperature of -20°C for 5 hours to obtain modified graphene. Example 5

[0068] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 1 As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 2 μm, and the functional layer includes the following raw materials in parts by weight: 4 parts of aluminum oxide, 3 parts of modified cubic boron nitride, 3 parts of modified silicon carbide, 2 parts of modified graphene, and 3 parts of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0069] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0070] The tool substrate was immersed in acetone for ultrasonic cleaning for 5 minutes, then immersed in ethanol for ultrasonic cleaning for 6 minutes, blown dry, and placed in a vacuum chamber;

[0071] Evacuate the vacuum chamber and preheat it to 450°C;

[0072] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology for 20 minutes.

[0073] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 60 sccm and the Ar flow rate is 120 sccm, and the tool substrate is coated with a film to form a functional layer using the existing magnetron sputtering technology, and the coating time is 80 minutes;

[0074] After coating, cool for 120 minutes.

[0075] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in 7 times the weight and 30% mass fraction of nitric acid, heating to 90°C, stirring for 3 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in 8 times the weight of water, irradiating under N2O or N2 conditions, the ventilation time is 30 minutes, the irradiation dose rate is 90Gy / min, the total dose is 100kGy, and filtering to obtain product B: dispersing product B in 7 times the weight and 3% volume fraction of siloxane solution, heating to 100°C, reacting for 5 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0076] In this embodiment, the preparation method of the modified silicon carbide is as follows: 10 parts by weight of nano-silicon carbide are added to 40 parts by weight of a hydrochloric acid solution with a mass fraction of 40%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 30 parts of a sodium chromate solution with a concentration of 200 g / L, and then 20 parts of glucose with a concentration of 50 g / L, 6 parts of polyethylene glycol with a concentration of 10 g / L, and 10 parts of sodium hexametaphosphate with a concentration of 40 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 160°C and reacted for 50 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 1000°C for 4 hours to obtain modified silicon carbide.

[0077] In a specific implementation, the preparation method of the modified graphene is as follows: 6 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 1.5 parts of nano-Cr powder are added and ball milled for 50 minutes. The ball-milled liquid is stirred at a temperature of 160°C for 2 hours, and then freeze-dried at a temperature of -20°C for 5 hours to obtain modified graphene. Example 6

[0078] The embodiment of the present invention provides a high hardness micro-diameter ball end mill coating, such as Figure 2 As shown, it includes at least one functional layer deposited on the micro-diameter ball end milling cutter, the thickness of the functional layer is 1.5 μm, and the functional layer includes the following raw materials in parts by weight: 3 parts of aluminum oxide, 2.5 parts of modified cubic boron nitride, 3 parts of modified silicon carbide, 1.5 parts of modified graphene, and 2 parts of titanium nitride. The method for preparing the high-hardness micro-diameter ball end milling cutter coating includes the following steps:

[0079] Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material;

[0080] The tool substrate was immersed in acetone for ultrasonic cleaning for 4 minutes, then immersed in ethanol for ultrasonic cleaning for 5 minutes and then blown dry. The part of the tool substrate to be coated was immersed below the liquid surface of a mixed liquid in a container. The mixed liquid included nano-titanium powder and Acetobacter xylinum fermentation liquid in a mass ratio of 1:25. After incubation at 30°C for 42 hours, the tool substrate was removed, washed twice with distilled water, blown dry, and placed in a vacuum chamber.

[0081] Evacuate the vacuum chamber and preheat it to 400°C;

[0082] The tool substrate was ion cleaned and etched using the existing arc-enhanced glow discharge technology, which took 15 minutes.

[0083] N2 and Ar are continuously introduced into the vacuum chamber, wherein the N2 flow rate is 50 sccm and the Ar flow rate is 100 sccm, and the tool substrate is coated with a film to form a functional layer using an existing magnetron sputtering technology, and the coating time is 70 minutes;

[0084] After coating, cool for 105 minutes.

[0085] The preparation method of the modified cubic boron nitride is as follows: placing cubic boron nitride powder in nitric acid with a mass fraction of 20% by weight, heating to 85°C, stirring for 2.5 hours, centrifuging, washing and drying for use to obtain product A; dispersing product A in water with a weight of 7 times, irradiating under N2O or N2 conditions, the ventilation time is 25 minutes, the irradiation dose rate is 80Gy / min, the total dose is 95kGy, and filtering to obtain product B: dispersing product B in a siloxane solution with a volume fraction of 2% by weight by 6 times, heating to 90°C, reacting for 4 hours, filtering, and vacuum drying to obtain modified cubic boron nitride.

[0086] In this embodiment, the preparation method of the modified silicon carbide is as follows: 8 parts by weight of nano-silicon carbide are added to 35 parts of a hydrochloric acid solution with a mass fraction of 35%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; the pretreated silicon carbide is added to 25 parts of a sodium chromate solution with a concentration of 150 g / L, and then 15 parts of glucose with a concentration of 45 g / L, 5 parts of polyethylene glycol with a concentration of 8 g / L, and 7 parts of sodium hexametaphosphate with a concentration of 30 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 155°C and reacted for 40 minutes; after the reaction is completed, the mixture is cooled to below 90°C, the suspension is extracted, filtered, washed, and dried, and the dried powder is sintered at 900°C for 3.5 hours to obtain modified silicon carbide.

[0087] In a specific implementation, the preparation method of the modified graphene is as follows: 5 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 1 part of nano-Cr powder is added and ball-milled for 40 minutes. The ball-milled liquid is stirred at a temperature of 140°C for 1.5 hours, and then freeze-dried at a temperature of -30°C for 4 hours to obtain modified graphene.

[0088] Comparative Example 1: Compared with Example 3, the modified cubic boron nitride is replaced by ordinary cubic boron nitride.

[0089] Comparative Example 2: Compared with Example 3, the modified silicon carbide is replaced by ordinary silicon carbide.

[0090] Comparative Example 3: Compared with Example 3, the modified graphene is replaced by ordinary graphene.

[0091] Comparative Example 4: Compared with Example 3, the modified cubic boron nitride is replaced by ordinary cubic boron nitride, the modified silicon carbide is replaced by ordinary silicon carbide, and the modified graphene is replaced by ordinary graphene.

[0092] Comparative Example 5: A commercially available coated micro-diameter ball end mill.

[0093] The microhardness of the coatings of Examples 1-6 and Comparative Examples 1-4 was measured using a nanoindenter. The test results are shown in the following table:

[0094] Group Hardness (GPa) Example 1 42 Example 2 43 Example 3 45 Example 4 44 Example 5 43 Example 6 48 Comparative Example 1 31 Comparative Example 2 30 Comparative Example 3 32 Comparative Example 4 26 Comparative Example 5 25

[0095] From the above results, it can be seen that the coating prepared by the present invention has high hardness. By adding modified cubic boron nitride, modified silicon carbide and modified graphene, the three have a synergistic effect and can improve the hardness of the coating.

[0096] It should be noted that, for the sake of simplicity, the aforementioned embodiments are described as a series of action combinations. However, those skilled in the art should be aware that the present invention is not limited by the order of the actions described, because according to the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the embodiments described are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also fall within the scope of protection of the present invention.

Claims

1. A high-hardness coating for a micro-diameter ball-end milling cutter, comprising at least one functional layer deposited on the micro-diameter ball-end milling cutter, characterized in that: The thickness of the functional layer is 1-2 μm, and the functional layer comprises the following raw materials in parts by weight: 2-4 parts of aluminum oxide, 2-3 parts of modified cubic boron nitride, 1-3 parts of modified silicon carbide, 1-2 parts of modified graphene, and 1-3 parts of titanium nitride; The preparation method of modified cubic boron nitride is as follows: placing cubic boron nitride powder in nitric acid with a mass fraction of 10-30% by weight at 5-7 times its weight, heating to 80-90°C, stirring for 2-3 hours, centrifuging, washing, and drying for use to obtain product A; dispersing product A in water with a mass fraction of 10-30% by weight, irradiating under N2O or N2 conditions for 20-30 minutes, the irradiation dose rate being 70-90 Gy / min and the total dose being 90-100 kGy, and filtering to obtain product B; dispersing product B in a siloxane solution with a volume fraction of 1-3% by weight at 4-7 times its weight, heating to 80-100°C, reacting for 3-5 hours, filtering, and vacuum drying to obtain modified cubic boron nitride; The preparation method of modified silicon carbide is as follows: 6-10 parts by weight of nano-silicon carbide are added to 30-40 parts by weight of a hydrochloric acid solution having a mass fraction of 30-40%, and after sufficient stirring, the mixture is centrifuged, washed, and dried in sequence to obtain pretreated silicon carbide; The pretreated silicon carbide is added to 20-30 parts of a sodium chromate solution with a concentration of 100-200 g / L, and then 10-20 parts of glucose with a concentration of 40-50 g / L, 4-6 parts of polyethylene glycol with a concentration of 5-10 g / L, and 5-10 parts of sodium hexametaphosphate with a concentration of 20-40 g / L are added; the mixture is pumped into an autoclave under continuous stirring, heated to 150-160° C., and reacted for 30-50 minutes; after the reaction is completed, the mixture is cooled to below 90° C., the suspension is withdrawn, filtered, washed, and dried, and the dried powder is sintered at 800-1000° C. for 3-4 hours to obtain modified silicon carbide; The preparation method of modified graphene is as follows: 4-6 parts by weight of graphene oxide are dispersed in anhydrous ethanol and ultrasonically vibrated to prepare a graphene oxide dispersion, and then 0.5-1.5 parts of nano-Cr powder are added and ball milled for 30-50 minutes. The ball-milled liquid is stirred at a temperature of 120-160°C for 1-2 hours, and then freeze-dried at a temperature of -40 to -20°C for 3-5 hours to obtain modified graphene.

2. The high-hardness, small-diameter ball-end milling cutter coating according to claim 1, characterized in that: The functional layer includes the following raw materials in parts by weight: 2.5-3.5 parts of aluminum oxide, 2.2-2.8 parts of modified cubic boron nitride, 1.5-2.5 parts of modified silicon carbide, 1.3-1.7 parts of modified graphene, and 1.5-2.5 parts of titanium nitride.

3. The method for preparing a high-hardness, small-diameter ball-end milling cutter coating according to any one of claims 1 to 2, characterized in that: The steps include: Weigh the raw materials of the functional layer according to the ratio and mix them evenly to form the target material; The tool substrate is pre-treated and placed in a vacuum chamber; Evacuate the vacuum chamber and preheat it to 350-450℃; The tool substrate is ion cleaned and etched using existing arc-enhanced glow discharge technology, which takes 10-20 minutes. N2 and Ar are continuously introduced into the vacuum chamber, and the tool substrate is coated with a film to form a functional layer using existing magnetron sputtering technology; After coating, cool for 90-120 minutes.

4. The method for preparing a high-hardness, small-diameter ball-end milling cutter coating according to claim 3, wherein: The N2 flow rate is 40-60 sccm, the Ar flow rate is 80-120 sccm, and the coating time is 60-80 minutes.

5. The method for preparing a high-hardness, small-diameter ball-end milling cutter coating according to claim 4, characterized in that: The pretreatment of the tool substrate comprises immersing the tool substrate in acetone for ultrasonic cleaning for 3-5 minutes, then immersing the tool substrate in ethanol for ultrasonic cleaning for 4-6 minutes, and then drying.

6. The method for preparing a high-hardness, small-diameter ball-end milling cutter coating according to claim 5, characterized in that: The method also includes, after drying, immersing the to-be-coated portion of the tool substrate below the liquid surface of a mixed liquid in a container, wherein the mixed liquid includes nano-titanium powder and Acetobacter xylinum fermentation liquid in a mass ratio of 1:20-30, culturing at 30-35°C for 36-48 hours, then taking out the tool substrate, washing it with distilled water 2-3 times, and then drying it.

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