A quaternary tialtann-based nanocomposite functional die coating and a preparation method thereof

Abstract

The application relates to the technical field of coating preparation, in particular to a quaternary TiAlTaN-based nanocomposite functional mold coating and a preparation method thereof, which comprises the following steps: S1: ball milling the material to obtain uniformly mixed alloy powder; S2: performing hot-press sintering treatment on the alloy powder to prepare a composite target material for standby; S3: performing pretreatment on the surface of a mold substrate; S4: performing pretreatment before coating deposition; S5: adopting a magnetron sputtering technology, taking the composite target material prepared in S2 as a metal source, and performing coating deposition on the surface of the mold substrate under a nitrogen reaction atmosphere; S6: performing segmented heat treatment on the coating deposited in S5; and S7: performing mechanical polishing on the surface of the coating after heat treatment. Through optimization and synergy of multiple components and nanostructure regulation, the application realizes the unity of wear resistance, oxidation resistance and high bonding strength of the coating, and meets the requirements of long-term stable operation of the mold under high-temperature, high-speed and high-load working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating preparation, in particular to a quaternary TiAlTaN-based nanocomposite functional die coating and a preparation method thereof. BACKGROUND

[0002] With the continuous development of the die industry towards precision, the requirements for stamping efficiency and stamping quality are becoming higher and higher. For example, when stamping materials such as copper and silver, the die surface is easy to bond with the stamping material, causing problems such as unclear stamping pattern, difficult demolding, etc. Therefore, the die coating is required to have good self-lubricating performance under the premise of ensuring high wear resistance and thermal stability.

[0003] The existing coating technology mainly has the problems of insufficient wear resistance, heat resistance and oxidation resistance, poor bonding between the coating and the substrate, and difficulty in microstructure regulation, which directly affects the stability and reliability of the die in continuous production. In order to overcome the above technical problems, a quaternary TiAlTaN-based nanocomposite functional die coating and a preparation method thereof are proposed, aiming to solve the various deficiencies in traditional coatings. SUMMARY

[0004] Based on the above purpose, the present application provides a quaternary TiAlTaN-based nanocomposite functional die coating and a preparation method thereof.

[0005] A quaternary TiAlTaN-based nanocomposite functional die coating, comprising Ti, Al, Ta, Si, Cr and N; wherein each component accounts for,

[0006] Ti accounts for 30-40%;

[0007] Al accounts for 10-20%;

[0008] Ta accounts for 5-15%;

[0009] Si accounts for 1-5%;

[0010] Cr accounts for 1-5%;

[0011] The balance is N.

[0012] Optionally, the coating has a nanocolumnar crystal structure, the grain size is 5-50 nm, and Si, Cr and nitrogen elements are enriched at the grain boundaries.

[0013] A preparation method of a quaternary TiAlTaN-based nanocomposite functional die coating, comprising the following steps:

[0014] S1: titanium, aluminum, tantalum, silicon and chromium are weighed and mixed according to a predetermined ratio, and then placed in a ball milling device for high-energy ball milling to obtain uniformly mixed alloy powder;

[0015] S2: heat-press sintering the alloy powder obtained in S1 to prepare a composite target for standby;

[0016] S3: sequentially performing mechanical polishing and polishing on the surface of the mold substrate, and then performing ultrasonic cleaning and vacuum chamber ion etching cleaning to remove surface contaminants and activate the surface of the substrate, thereby preparing for coating deposition;

[0017] S4: placing the mold substrate treated in S3 in a coating vacuum chamber, vacuumizing to a preset vacuum degree, then introducing a mixed gas of argon and nitrogen into the vacuum chamber to stabilize the atmosphere in the chamber, and completing the pretreatment before coating deposition;

[0018] S5: using the composite target prepared in S2 as a metal source, and using a magnetic control sputtering technology to deposit a coating on the surface of the mold substrate in a nitrogen reaction atmosphere, so that Ti, Al, Ta, Si and Cr react with N element to form a nano-composite coating structure mainly containing TiAlTaN and containing Si and Cr nitride phases;

[0019] S6: performing segmented heat treatment on the coating deposited in S5;

[0020] S7: mechanically polishing the surface of the coating after heat treatment, thereby obtaining a final quaternary TiAlTaN-based nano-composite functional mold coating.

[0021] Optionally, in step S1, the ball milling time of the titanium, aluminum, tantalum, silicon and chromium powders is 1-5 hours, the ball-to-material ratio is 5:1-15:1, the ball milling speed is 200-500 rpm, and the average particle size of the obtained powder after ball milling is 1-5 μm.

[0022] Optionally, in step S2, the alloy powder obtained by ball milling is sintered in a hot isostatic pressing device, the temperature is controlled at 1200-1500 °C, the pressure holding time is 2-6 hours, the applied pressure is 10-50 MPa, and the process of preparing the composite target is completed in a vacuum environment.

[0023] Optionally, in step S3, after the mold substrate is mechanically polished and polished, the surface roughness is controlled at 0.2 μm, then ultrasonic cleaning is performed for 10-30 minutes, and then ion bombardment is performed for 5-20 minutes at an ion etching voltage of -300 to -800 V in a vacuum environment.

[0024] Optionally, in step S4, after the substrate is placed in the coating chamber, vacuumization is performed to 1×10^-3 Pa, and a mixed gas of argon and nitrogen is introduced for pretreatment, the argon flow rate is 10 sccm, the nitrogen flow rate is 5 sccm, and the volume flow rate ratio of argon to nitrogen is maintained at 2:1-4:1 throughout the process.

[0025] Optionally, in step S5, when using magnetron sputtering deposition, the power of the composite target is 3-10 kW, the substrate bias is -50 to -150 V, the substrate temperature is 300-500 DEG C, and the deposition time is controlled to be 1-3 hours.

[0026] Optionally, in step S6, the coating after deposition is subjected to segmented heat treatment, the holding temperature of the first stage is 400-500 DEG C, and the holding time is 30-60 minutes; the holding temperature of the second stage is 600-700 DEG C, and the holding time is 30-60 minutes.

[0027] Optionally, in step S7, the coating after heat treatment is subjected to mechanical polishing, and the surface layer of 0.1-0.5 microns is removed, and the surface roughness of the final coating is controlled to be below 0.2 microns.

[0028] The beneficial effects of the present application are as follows:

[0029] In the present application, by introducing multi-component such as tantalum, silicon and chromium into the traditional TiAlN system, and using high-energy ball milling, hot-pressing sintering and magnetron sputtering process, the uniform distribution of each component in the coating and the optimization of the microstructure are realized, and the nano-pillar crystal structure is formed. The structure design ensures that the coating and the mold substrate have stable bonding force. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0031] Figure 1 The preparation method of the composite functional mold coating of the present application is shown in the figure. DETAILED DESCRIPTION

[0032] The present application will be described in detail below in combination with the drawings and specific embodiments. It should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and other alternative ways can also be used by those skilled in the art to implement them; and the drawings are only used to more specifically describe the embodiments, and are not intended to specifically limit the present application.

[0033] It is important to note that the use of "one embodiment," "an embodiment," "exemplary embodiment," "some embodiments," etc., in the specification does not necessarily refer to the same embodiment, although it may. In addition, the description of a particular feature, structure, or characteristic in connection with an embodiment does not imply that such feature, structure, or characteristic is included in all embodiments.

[0034] Generally, the terminology can be understood at least in part from usage in context. For example, the term "one or more" as used herein, depending at least in part upon context, can be used to describe any feature, structure, or characteristic in a singular sense or can be used to describe combinations of features, structures or characteristics in a plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but rather can instead allow for existence of additional factors not necessarily expressly described, again, at least in part, depending at least in part on context. Embodiments

[0035] A quaternary TiAlTaN-based nanocomposite functional die coating, comprising Ti, Al, Ta, Si, Cr and N; wherein each component is 35% by mass,

[0036] Ti accounts for 35%;

[0037] Al accounts for 15%;

[0038] Ta accounts for 10%;

[0039] Si accounts for 3%;

[0040] Cr accounts for 3%;

[0041] The balance is N.

[0042] The coating has a nanocolumnar crystal structure, the grain size is 5-50 nm, and the grain boundaries are rich in Si, Cr and nitrogen elements to improve the high-temperature oxidation resistance and hardness of the coating.

[0043] As shown in Figure 1 A preparation method of a quaternary TiAlTaN-based nanocomposite functional die coating, comprising the following steps:

[0044] S1: titanium, aluminum, tantalum, silicon and chromium are weighed and mixed according to a predetermined proportion, then placed in a ball milling device for high-energy ball milling to obtain uniformly mixed alloy powder;

[0045] S2: The alloy powder obtained in S1 is subjected to hot-pressing sintering treatment to prepare a composite target material for standby use;

[0046] S3: sequentially performing mechanical polishing and polishing on the surface of the mold base, and then performing ultrasonic cleaning and ion etching cleaning in a vacuum chamber to remove surface contaminants and activate the surface of the base, thereby preparing for coating deposition;

[0047] S4: placing the mold base treated in S3 in a coating vacuum chamber, vacuumizing to a preset vacuum degree, then introducing a mixed gas of argon and nitrogen into the vacuum chamber to stabilize the atmosphere in the chamber, and completing the pretreatment before coating deposition;

[0048] S5: using a magnetron sputtering technique, taking the composite target prepared in S2 as a metal source, and depositing a coating on the surface of the mold base in a nitrogen reaction atmosphere, so that Ti, Al, Ta, Si, Cr and N elements react to form a nano-composite coating structure mainly containing TiAlTaN and containing Si and Cr nitride phases;

[0049] S6: performing segmented heat treatment on the coating deposited in S5;

[0050] S7: mechanically polishing the surface of the coating after heat treatment to obtain the final quaternary TiAlTaN-based nano-composite functional mold coating.

[0051] In step S1, the ball milling time of titanium, aluminum, tantalum, silicon and chromium powders is 3 hours, the ball-to-material ratio is 10:1, and the ball milling speed is 300 rpm. The average particle size of the obtained powder after ball milling is 3 μm.

[0052] In step S2, the alloy powder obtained by ball milling is sintered in a hot isostatic pressing device, the temperature is controlled at 1300°C, the pressure holding time is 4 hours, the applied pressure is 30 MPa, and the process of preparing the composite target is completed in a vacuum environment.

[0053] In step S3, after mechanical polishing and polishing of the mold base, the surface roughness is controlled at 0.2 μm, then ultrasonic cleaning is performed for 20 minutes, and then ion bombardment is performed for 10 minutes at an ion etching voltage of -500 V in a vacuum environment.

[0054] In step S4, after placing the base in the coating chamber, vacuumize to 1x10^-3 Pa, and introduce a mixed gas of argon and nitrogen for pretreatment, the argon flow rate is 10 sccm, the nitrogen flow rate is 5 sccm, and the volume flow rate ratio of argon to nitrogen is maintained at 3:1 throughout the process.

[0055] In step S5, when using magnetron sputtering deposition, the power of the composite target is 5 kW, the substrate bias is -100 V, the substrate temperature is 400°C, and the deposition time is controlled at 2 hours.

[0056] In step S6, the coating after deposition is subjected to a segmented heat treatment, the holding temperature of the first stage is 450℃, and the holding time is 40 minutes; the holding temperature of the second stage is 650℃, and the holding time is 40 minutes.

[0057] In step S7, the coating after heat treatment is subjected to mechanical polishing, and the surface layer of 0.3μm is removed, and the surface roughness of the final coating is less than 0.1μm. Embodiment

[0058] Formulation and proportion

[0059] The proportion of Ti is 30%; the proportion of Al is 10%; the proportion of Ta is 5%; the proportion of Si is 1%; the proportion of Cr is 1%; and the balance is N.

[0060] Specific preparation steps

[0061] S1: titanium powder, aluminum powder, tantalum powder, silicon powder, and chromium powder are weighed according to the above formulation and uniformly mixed; then the mixed powder is placed in a ball milling device, the ball milling time is set to 1 hour, the ball-to-material ratio is 5:1, and the ball milling speed is 200 rpm; after ball milling, the average particle size of the obtained powder is about 1μm;

[0062] S2: the alloy powder obtained in S1 is placed in a hot isostatic pressing device and sintered in a vacuum environment, the sintering temperature is 1200℃, the pressure holding time is 2 hours, and the applied pressure is 10MPa; finally, a Ti-Al-Ta-Si-Cr composite target material with uniform composition distribution and high density is obtained;

[0063] S3: the mold base is first mechanically polished and polished to control the surface roughness Ra to be 0.2μm; then it is ultrasonically cleaned for 10 minutes to remove surface oil and debris; then it is ion etched in a vacuum chamber for 5 minutes at an ion etching voltage of-300V to remove surface contamination and activate the surface of the base;

[0064] S4: the pretreated base is placed in a vacuum chamber, vacuumed to 1×10^-3Pa, and then a mixed gas of argon (flow rate 10sccm) and nitrogen (flow rate 5sccm) is introduced for pretreatment, ensuring that the volume flow ratio of argon to nitrogen is about 2:1; after the atmosphere in the chamber is stabilized, the next stage is entered;

[0065] S5: under a nitrogen reaction atmosphere, the composite target material prepared in step S2 is used as a metal source to deposit a coating on the surface of the base by a magnetron sputtering technique; at this time, the power of the composite target material is 3kW, the base bias is-50V, the base temperature is 300℃, and the deposition time is 1 hour; so that Ti, Al, Ta, Si, and Cr react and deposit in a nitrogen environment to form a nano-composite coating mainly composed of TiAlTaN, containing Si and Cr nitride phases.

[0066] S6: Two-stage heat treatment is performed on the deposited coating: the first stage is heat preservation at 400°C for 30 minutes, and the second stage is heat preservation at 600°C for 30 minutes; the segmented heat preservation can effectively release the residual stress of the coating and improve the film layer density and bonding force;

[0067] S7: After the heat treatment, mechanical polishing is performed on the surface of the coating to remove about 0.1 μm of the surface layer, and the surface roughness Ra of the coating is 0.15 μm, and finally a smooth and dense TiAlTaN-based nanocomposite functional mold coating is obtained. Embodiment

[0068] Formulation and proportion

[0069] The proportion of Ti is 40%; the proportion of Al is 20%; the proportion of Ta is 15%; the proportion of Si is 5%; the proportion of Cr is 5%; and the balance is N.

[0070] Specific preparation steps

[0071] S1: According to the above formulation, titanium powder, aluminum powder, tantalum powder, silicon powder and chromium powder are weighed and uniformly mixed; then the mixed powder is placed in a ball milling device, the ball milling time is set to 5 hours, the ball-to-material ratio is 15:1, and the ball milling speed is 500 rpm; the average particle size of the obtained powder after ball milling is about 5 μm;

[0072] S2: The alloy powder obtained in S1 is placed in a hot isostatic pressing device and sintered in a vacuum environment, the sintering temperature is 1500°C, the pressure holding time is 6 hours, and the applied pressure is 50 MPa; finally, a Ti-Al-Ta-Si-Cr composite target material with uniform composition distribution and high density is obtained;

[0073] S3: First, the mold substrate is mechanically polished and polished to control the surface roughness Ra to be 0.2 μm; then ultrasonic cleaning is performed for 30 minutes to remove surface oil and debris; then ion etching is performed in a vacuum chamber at an ion etching voltage of -800 V for 20 minutes to remove surface contamination and activate the surface of the substrate;

[0074] S4: The pretreated substrate is placed in a vacuum chamber, vacuumed to 1x10^-3 Pa, and then a mixed gas of argon (flow rate 10 sccm) and nitrogen (flow rate 5 sccm) is introduced for pretreatment, ensuring that the volume flow ratio of argon to nitrogen is about 4:1, and then the next stage is entered after the chamber atmosphere is stable;

[0075] S5: Under the nitrogen reaction atmosphere, the composite target prepared in step S2 is used as the metal source to deposit the coating on the substrate surface by the magnetron sputtering technology; at this time, the power of the composite target is 10 kW, the substrate bias is -150 V, the substrate temperature is 500°C, and the deposition time is 3 hours, so that Ti, Al, Ta, Si and Cr react and deposit to form the TiAlTaN-based nanocomposite coating containing Si and Cr nitride phases in the nitrogen environment;

[0076] S6: The deposited coating is subjected to two-stage heat treatment: the first stage is at 500°C for 60 minutes, and the second stage is at 700°C for 60 minutes; the segmented heat preservation can effectively release the residual stress of the coating and improve the film layer density and the bonding force;

[0077] S7: After the heat treatment, the coating surface is mechanically polished to remove about 0.5 μm of the surface layer, and the coating surface roughness Ra is 0.2 μm, and finally a smooth and dense TiAlTaN-based nanocomposite functional mold coating is obtained.

[0078] Comparative Example 1

[0079] Formulation and components: the coating only contains Ti and N, a commercial TiN target is used, and no other added components;

[0080] Preparation steps:

[0081] S1: The mold substrate is first mechanically polished to control the surface roughness Ra to be within 0.5 μm; then the ultrasonic cleaning machine is used to clean in ethanol for 10 minutes to remove surface oil and impurities, and finally air-dried in air;

[0082] S2: The pretreated substrate is placed in a direct current magnetron sputtering device to deposit a TiN coating at a substrate temperature of 350°C; the target power is set to 1 kW, the substrate bias is -50 V, and the deposition time is 1 hour, and finally a TiN coating with a thickness of about 2 μm is obtained;

[0083] S3: After the coating deposition is completed, the sample is placed in an annealing furnace and annealed at 500°C for 30 minutes under a nitrogen protective atmosphere to improve the coating density and the bonding strength between the film layer and the substrate.

[0084] Table 1 Comparison of performance parameters of finished products

[0085] Performance indicators Comparative Example 1 Example 1 Example 2 Example 3 Microhardness (HV0.05) 2800 3400 3200 3300 Film / substrate adhesion (N) 60 80 75 78 Friction coefficient (dry friction) 0.28 0.18 0.2 0.19 Oxidation onset temperature (°C) 700 850 830 840 Thickness uniformity (±%) ±3.0 ±2.0 ±2.5 ±2.2 Dry sliding wear rate (x10^-5 mm^3 / N·m) 1.5 0.6 0.8 0.7 Coating surface roughness Ra (μm) 0.15 0.1 0.15 0.2

[0086] As can be seen from the above Table 1, the microhardness, film / base bonding force, friction coefficient, oxidation initiation temperature, thickness uniformity, wear rate and surface roughness of Example 1 are all better than those of the comparative example and the other two examples, showing better wear resistance and thermal stability, and being able to meet the requirements of high hardness, low friction and high temperature resistance of the mold coating; Example 2 and Example 3 have slight differences in some indicators; the comparative example has relatively poor overall performance; the hardness, bonding force and temperature resistance of the sample of the comparative example are all inferior to those of the three examples, indicating that the preparation method and the formula of the present application are not used or not fully utilized, and it is difficult to balance high hardness and excellent tribological performance.

[0087] In summary, by the preparation method of the quaternary TiAlTaN-based nano-composite functional mold coating, a nano-composite structure can be formed among Ti, Al, Ta, Si, Cr and N elements, greatly improving the hardness, thermal stability and wear resistance of the mold coating. Among them, the indicators of Example 1 are the best, verifying the best effect within the given formula and process parameter range

[0088] The present application encompasses any alternative, modification, equivalent method and scheme made on the essence and scope of the present application. In order to make the public have a thorough understanding of the present application, specific details are described in the following preferred embodiments of the present application, and the present application can also be completely understood without the description of these details for those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the present application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0089] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can also be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a quaternary TiAlTaN-based nanocomposite functional die coating, characterized in that, The mold coating comprises Ti, Al, Ta, Si, Cr and N; wherein each component accounts for, by mass percentage, Ti accounts for 30-40%; Al accounts for 10-20%; Ta accounts for 5-15%; Si accounts for 1-5%; Cr accounts for 1-5%; the balance is N; The preparation method comprises the following steps: S1: titanium, aluminum, tantalum, silicon and chromium are weighed and mixed in a predetermined proportion, then placed in a ball milling device for high-energy ball milling to obtain uniformly mixed alloy powder; S2: the alloy powder obtained in S1 is subjected to hot-press sintering treatment to prepare a composite target material for standby; S3: the surface of the mold substrate is sequentially subjected to mechanical polishing and polishing, then subjected to ultrasonic cleaning and vacuum chamber ion etching cleaning to remove surface contaminants and activate the surface of the substrate, thereby preparing for coating deposition; S4: the mold substrate treated in S3 is placed in a vacuum chamber, vacuum is drawn to a preset vacuum degree, then a mixed gas of argon and nitrogen is introduced into the vacuum chamber to stabilize the atmosphere in the chamber, thereby completing the pretreatment before coating deposition; S5: a composite target material prepared in S2 is used as a metal source to perform coating deposition on the surface of the mold substrate in a nitrogen reaction atmosphere, so that Ti, Al, Ta, Si and Cr react with N elements to form a nano-composite coating structure mainly composed of TiAlTaN and containing Si and Cr nitride phases; S6: the coating deposited in S5 is subjected to segmented heat treatment, wherein the holding temperature of the first stage is 400-500 DEG C, and the holding time is 30-60 minutes; the holding temperature of the second stage is 600-700 DEG C, and the holding time is 30-60 minutes; S7: the surface of the coating after heat treatment is subjected to mechanical polishing to obtain the final quaternary TiAlTaN-based nano-composite functional mold coating.

2. The method according to claim 1, wherein the method is characterized by, The coating has a nano-pillar crystal structure, the grain size is 5-50 nm, and the grain boundaries are rich in Si, Cr and nitrogen elements.

3. The method according to claim 1, wherein the method is characterized by, In step S1, the titanium, aluminum, tantalum, silicon and chromium powders are ball milled for 1-5 hours, the ball-to-material ratio is 5:1-15:1, and the ball milling speed is 200-500 rpm; the average particle size of the obtained powder after ball milling is 1-5 μm.

4. The method according to claim 1, wherein the method is characterized by, In step S2, the alloy powder obtained by ball milling is sintered in a hot isostatic pressing device, the temperature is controlled at 1200-1500 DEG C, the pressure holding time is 2-6 hours, the applied pressure is 10-50 MPa, and the process of preparing the composite target material is completed in a vacuum environment.

5. The method according to claim 1, wherein the method is characterized by, In step S3, after the mold substrate is mechanically polished and polished, the surface roughness is controlled at 0.2 μm, then ultrasonic cleaning is performed for 10-30 minutes, and then ion bombardment is performed at an ion etching voltage of-300 to-800 V for 5-20 minutes in a vacuum environment.

6. The method according to claim 1, wherein the method is characterized by, In step S4, the substrate is placed in a coating chamber, vacuum is drawn to 1*10^-3 Pa, and a mixed gas of argon and nitrogen is introduced for pretreatment, the argon flow rate is 10 sccm, the nitrogen flow rate is 5 sccm, and the volume flow rate ratio of argon to nitrogen is maintained at 2:1 throughout the process.

7. The method according to claim 1, wherein the method is characterized by, In step S5, when using magnetron sputtering deposition, the power of the composite target is 3-10 kW, the substrate bias is -50 to -150 V, the substrate temperature is 300-500 DEG C, and the deposition time is controlled to be 1-3 hours.

8. The method according to claim 1, wherein the method is characterized by, In step S7, the coating after heat treatment is mechanically polished to remove a surface layer of 0.1-0.5 microns, and the surface roughness of the final coating is controlled to be below 0.2 microns.

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