Preparation method and application of high-temperature insulating wear-resistant coating

Abstract

The invention belongs to the field of high-temperature insulation, and relates to a preparation method and application of a high-temperature insulation wear-resistant coating. Based on an existing magnetron sputtering technology, the method sequentially comprises the following steps of treatment before plating, Ar ion sputtering cleaning and deposition of an aluminum oxide-based coating. And in the deposition process, Al and Cr target materials are adopted, and reaction co-sputtering is carried out in oxygen and nitrogen atmospheres, so that the target coating is formed. And preparing an aluminum oxide base layer on the pre-deposited bonding layer by using a magnetron sputtering technology to obtain a dual-phase structure formed by corundum type AlCrON and CrN. The prepared aluminum oxide-based coating shows excellent insulating property and thermal stability under a high-temperature condition, and meanwhile, good wear resistance is realized by regulating and controlling phase composition in the coating. Furthermore, the defects and phase structure of the coating are optimized, so that the whole coating has excellent insulation characteristics and mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature insulation and relates to the preparation of alumina-based high-temperature insulating coatings. Background Technology

[0002] Welding contact tips are made of copper alloys such as brass, copper, and chromium-zirconium copper. They are crucial consumable components in gas metal arc welding (GMAW). During welding of narrow-gap bevel workpieces, the outer side of the contact tip can easily come into contact with the bevel sidewall, causing electrical discharge and resulting in tip burn-out, negatively impacting weld quality. To address this issue, an insulating layer of a certain thickness is typically prepared at the point where the contact tip penetrates the workpiece bevel. This coating must, on the one hand, ensure insulation between the copper alloy substrate and the weldment at high temperatures, achieving electrical isolation; on the other hand, it needs sufficient adhesion strength, thermal shock resistance, and thermal fatigue resistance to prevent cracking and peeling due to thermal mismatch at high temperatures; furthermore, the coating must have good wear resistance to reduce wear during contact between the contact tip and the weldment sidewall.

[0003] Currently, the preparation of alumina coatings mainly relies on spraying technology. However, due to the inherent characteristics of the thermal spraying process, the resulting coatings typically suffer from high brittleness, high porosity, and uneven thickness. Furthermore, the alumina prepared by spraying contains a large number of oxygen vacancies that are difficult to control. Therefore, the coating often requires post-treatment such as sealing, heat treatment, or thermal diffusion remelting, resulting in a complex and inefficient preparation process for conductive tip coatings.

[0004] In contrast, magnetron sputtering technology offers advantages such as dense film formation, uniform deposition, and fewer defects, making it particularly suitable for the preparation of alumina coatings. In particular, magnetron sputtering facilitates the control of oxygen vacancy concentration through nitrogen doping and optimizes the phase structure through doping with other elements, thereby improving the wear resistance of the coating. Publication number CN107190229A discloses a method for preparing a self-assembled nano-oxynitride high-temperature resistant coating, employing arc ion plating and magnetron sputtering. An AlTiN coating is first placed on the substrate as a support layer before sputtering deposition. This method primarily achieves its effect by controlling the target distance and rotation speed, and is mainly used for the protection of conventional mechanical parts, cutting tools, and other alloy materials. However, for materials like welding conductive nozzles with copper as the substrate, there is currently no perfect protection method. In the magnetron sputtering preparation of oxide coatings, sputtering efficiency is generally low, and a long deposition time is often required to achieve the target thickness, severely limiting the preparation efficiency. Consequently, existing conductive nozzle protective coatings still suffer from technical problems such as complex processes, low preparation efficiency, and poor insulation performance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for preparing a high-temperature insulating and wear-resistant coating and its application. It provides an alumina-based dual-phase coating with high preparation efficiency, excellent insulating and wear-resistant properties, and long-term structural stability at high temperatures.

[0006] The technical solution of this invention is implemented as follows: On one hand, the present invention provides a method for preparing a high-temperature insulating and wear-resistant coating, the steps of which are: (1) Polish the surface of the dispersed copper substrate, and then clean the polished dispersed copper with deionized water and anhydrous ethanol for 20-30 minutes. After cleaning, dry it with nitrogen and fix the dispersed copper substrate on the sample tray. The grinding and polishing steps are as follows: Grind and polish the dispersed copper block substrate or conductive tip sample on one side with 600-2000# sandpaper until the sample surface is smooth and flat. After grinding and polishing, the sample is ultrasonically cleaned with deionized water and anhydrous ethanol for 20-30 minutes in sequence until there is no dust on the surface.

[0007] (2) Install the dispersed copper block substrate and the conductive nozzle sample disk in the chamber of the multi-target magnetron sputtering instrument, close the chamber door and sequentially perform high vacuum, substrate heating, argon, oxygen and nitrogen to adjust the deposition gas pressure, open the substrate baffle, turn on the power and perform coating deposition. Use Al target and Cr target as target materials, dispersed copper as substrate, and magnetron sputtering technology to deposit alumina-based dual-phase coating.

[0008] The coating deposition conditions were as follows: a distance of 6 mm between the Al target, Cr target, and substrate, and a backplane vacuum of 6.4 × 10⁻⁶. -4 -7.5×10 -4 The heating temperature is 500 ℃, the deposition time is 12-18h, the bias power supply power is -60V~-200V, the Al metal target uses a DC power supply, the sputtering power is controlled at 100~200W, the flow rate of argon-oxygen mixture (argon-oxygen ratio 99:1) is 30 sccm, the flow rate of nitrogen is 8.5~11.5 sccm, and after sputtering, it is cooled to 50~60 ℃.

[0009] In this invention, oxygen flow rate is a key process parameter: while a higher oxygen flow rate can effectively suppress oxygen defects, it significantly reduces deposition efficiency; conversely, appropriately reducing the oxygen flow rate can retain oxygen vacancies to a certain extent, thereby improving deposition efficiency and achieving a balance between breakdown performance and preparation efficiency. Based on the charge compensation effect, after introducing nitrogen, nitrogen vacancies preferentially form and stably exist as a compensating defect, effectively assuming the positive charge share required to maintain the system's electrical neutrality, thus significantly reducing the driving force and necessity for oxygen vacancy formation, achieving the goal of reducing oxygen defects. Simultaneously, the addition of Cr, as an α-Cr₂O₃ nucleation site, promotes the formation of α-Al₂O₃. The key lies in the fact that both have the same hexagonal crystal structure (R-3c space group) and low lattice mismatch, thus significantly reducing the nucleation energy barrier of α-Al₂O₃. The introduction of Cr, through structural matching and thermodynamic synergy, effectively promotes the low-temperature crystallization and stable formation of the α-Al₂O₃ coating, ultimately forming a (Al,Cr)₂O₃ solid solution. Based on phase diagram thermodynamics and nucleation phase transition theory, the coating composition can be designed to obtain a two-phase structure composed of corundum-type AlCrON and CrN. This structure possesses excellent insulation properties, mechanical properties, and high-temperature stability, not only meeting the insulation and wear resistance requirements of copper conductive tips in high-temperature environments, but also extending to other high-temperature insulation applications.

[0010] Secondly, the present invention provides a high-temperature insulating thin film coating prepared by the above-described method, wherein the atomic percentage content of Al in the high-temperature insulating thin film coating is 24.5%–28.4%, the atomic percentage content of Cr is 10.2%–15.3%, the atomic percentage content of O is 48.8%–52.3%, and the atomic percentage content of N is 10.6%–12.5%. The above-described high-temperature insulating thin film coating has a two-phase structure composed of corundum-type AlCrON and CrN.

[0011] Thirdly, the present invention provides a method for preparing a high-temperature insulating welding conductive tip, the steps of which are: referring to the method for preparing a high-temperature insulating thin film coating, and replacing the dispersed copper substrate in the step with a welding conductive tip.

[0012] Fourthly, the present invention provides a high-temperature insulating welding conductive tip prepared using the above-described method, and the application of the above-described high-temperature insulating thin film coating in the field of welding conductive tip protection.

[0013] The present invention has the following beneficial effects: (1) Compared with existing plasma spraying technology, this invention uses magnetron sputtering technology to successfully prepare a dense, high-purity alumina-based protective coating on the surface of a complex-shaped copper conductive nozzle, which can be applied directly without subsequent processing. By precisely controlling the oxygen flow rate, the low preparation efficiency of traditional magnetron sputtering is effectively solved while ensuring the insulation performance of the coating.

[0014] (2) This invention introduces N and Cr elements during the magnetron sputtering process and designs the coating composition based on phase diagram thermodynamics and nucleation phase transformation theory to construct a two-phase structure composed of corundum-type AlCrON and CrN. Compared with traditional magnetron sputtered alumina coatings, this structure significantly reduces the internal defect concentration and combines the excellent insulation properties of the corundum phase with the high-strength CrN reinforcing phase, thereby greatly improving the overall insulation and mechanical properties of the coating.

[0015] (3) The breakdown strength of the coating of this invention reaches 186.8 kV / mm, which is significantly improved compared with the plasma-sprayed alumina coating. The coating deposition rate reaches 0.46 μm / h, which is 5 times that of the traditional magnetron sputtered alumina coating, and the wear rate is reduced to 30% of that of the alumina coating. The coating can still maintain structural stability under long-term service at 500℃ or instantaneous high temperature at 1000℃, demonstrating excellent high-temperature reliability and durability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The XRD patterns of the coatings prepared in Example 1 and Comparative Examples 1-2 are shown; where (a) is Example 1; (b) is Comparative Example 1; and (c) is Comparative Example 2.

[0018] Figure 2 The graph shows the changes in breakdown strength and deposition efficiency of the coatings prepared in Example 1 and Comparative Examples 1-2 as a function of oxygen content.

[0019] Figure 3 The diagram shows the breakdown strength of the coatings deposited per unit time using the preparation processes used in Example 1 and Comparative Examples 1-2.

[0020] Figure 4 The graphs show the high-temperature insulation resistance of the coatings prepared in Example 1 and Comparative Examples 1-2 as a function of temperature, where Example 1 is Al 43.2 O 56.8 Comparative Example 1 is Al 47.6 O 52.4 Comparative Example 2 is Al 38.7 O 61.3 .

[0021] Figure 5The surface and cross-sectional morphology of the coatings prepared in Example 1 and Comparative Examples 1-2 after 10 hours at 500°C; wherein Example 1 is Al 43.2 O 56.8 Comparative Example 1 is Al 47.6 O 52.4 Comparative Example 2 is Al 38.7 O 61.3 .

[0022] Figure 6 The XRD patterns of the coatings prepared in Example 2 and Comparative Examples 3-4 are shown; wherein Example 2 is an AlCr coating. 13.2 O, Comparative Example 3 is AlCr 5.5 O, Comparative Example 4 is AlCr 20.6 O.

[0023] Figure 7 The graph shows the change in breakdown strength of the coatings prepared in Example 2 and Comparative Examples 3-4 as a function of Cr content.

[0024] Figure 8 The high-temperature insulation resistance of coatings with different Cr contents prepared in Example 2 and Comparative Examples 3-4 varies with temperature, where Example 2 is AlCr 13.2 O, Comparative Example 3 is AlCr 5.5 O, Comparative Example 4 is AlCr 20.6 O.

[0025] Figure 9 The XRD patterns of the coatings prepared in Examples 3 and Comparative Examples 5-6 are shown; where (a) is Example 3; (b) is Comparative Example 5; and (c) is Comparative Example 6.

[0026] Figure 10 The surface morphology of the coatings prepared in Example 3 and Comparative Examples 5-6 after 30 hours at 500°C is compared with the cross-sectional morphology of Example 3, where Example 3 is AlCrON. 11.5 Comparative Example 5 is AlCrON 5.3 Comparative Example 6 is AlCrON 20.2 .

[0027] Figure 11 The graph shows the breakdown strength of the coatings prepared in Example 3 and Comparative Examples 5-6 as a function of N content, where Example 3 is AlCrON. 11.5 Comparative Example 5 is AlCrON 5.3 Comparative Example 6 is AlCrON 20.2 .

[0028] Figure 12 The graph shows the high-temperature insulation resistance of coatings with different N contents prepared in Example 3 and Comparative Examples 5-6 as a function of temperature.

[0029] Figure 13 The tribological properties of the coatings prepared in Example 3 and Comparative Examples 5-6 were tested; wherein (a) is the coating prepared in Example 3 (AlCrON). 11.5 ) and Example 1 (Al) 43.2 O 56.8 (a) Comparison of deposition rate, breakdown strength and wear depth; (b) Optical 3D profilometry morphology of wear tracks of coatings with different N contents; (c) SEM wear morphology and EDS analysis of Example 3. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise specified, the experimental methods used in the following experimental examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0032] This invention uses an X-ray diffractometer (XRD, XRO-6100) to analyze the compositional changes of coatings with different compositions.

[0033] The microstructure of the coating was characterized by field emission scanning electron microscopy (SEM, Sigma 300).

[0034] EDS spot scan analysis was used to analyze the elemental distribution of the coating.

[0035] The breakdown voltage of the coating was tested using an HC9310 insulation withstand voltage tester.

[0036] In-situ high-temperature insulation resistance testing was conducted using an insulation resistance meter and a muffle furnace.

[0037] Coating friction and wear tests were conducted using a Bruker UMT-2.

[0038] Example 1 In this embodiment, an alumina coating with high deposition efficiency shows a significant increase in film deposition rate after oxygen flow rate regulation. Figure 3 As shown, among the insulating coatings with different oxygen contents obtained by adjusting the oxygen flow rate, Example 1 can obtain an insulating coating with a higher breakdown voltage in a shorter deposition time, while also considering preparation efficiency. The preparation method is as follows: (1) Polish the dispersed copper block substrate or conductive tip sample with 1000# sandpaper on one side. After polishing, clean the sample with deionized water and anhydrous ethanol for 25 minutes in sequence. After cleaning, dry it with nitrogen and fix the dispersed copper substrate on the sample tray. (2) Install the dispersed copper substrate sample disk in the chamber of the magnetron sputtering instrument, attach the block dispersed copper to the substrate using high temperature adhesive, close the chamber door and sequentially perform high vacuum, substrate heating, argon and oxygen introduction, and adjust the deposition gas pressure, open the substrate baffle, turn on the power and perform coating deposition, use Al metal target as target material, use dispersed copper as substrate, and obtain coating by DC reactive sputtering deposition method of magnetron sputtering technology. After the temperature cools down, take out the coating sample and store it in a vacuum environment to obtain block dispersed copper with surface coating.

[0039] The coating deposition conditions were as follows: a distance of 6 mm between the Al metal target and the substrate, and a backplane vacuum of 7 × 10⁻⁶. - 4 Pa, heating temperature 500℃, deposition time 12h, bias power supply power -60V, Al metal target uses DC power supply, sputtering power control 150 W, argon flow rate 20 sccm, oxygen flow rate 2 sccm, argon gas purity ≥99.999%, after sputtering, cool to 50℃.

[0040] Table 1 shows the composition, thickness, and deposition efficiency of the coatings prepared in Example 1 and Comparative Examples 1-2. The detection results of this embodiment are shown in Table 1: Al 43.2%, O 56.8%, coating thickness 6.58µm, deposition rate 0.55µm / h. Figure 1 As shown in Figure (a), the coating phase in Example 1 is θ-type alumina; the coating surface is smooth and flat, and the coating is dense; as shown in Figure (a), the coating phase is θ-type alumina; the coating surface is smooth and flat, and the coating is dense; Figure 2 and Figure 4 As shown, the breakdown strength of the coating was tested to be 96 kV / mm, and the insulation resistance at 500℃ was 94 kΩ.

[0041] Comparative Example 1 The high-deposition-efficiency alumina coating of this comparative example was prepared using the same method as in Example 1, except for the deposition conditions. The deposition conditions for Comparative Example 1 are as follows: The distance between the Al metal target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4The heating temperature was 500℃, the deposition time was 12 h, the bias power was -60 V, the Al metal target used a DC power supply, the sputtering power was controlled at 150 W, the argon flow rate was 20 sccm, the oxygen flow rate was 1.5 sccm, the argon gas purity was ≥99.999%, and after sputtering, the temperature was cooled to 50℃.

[0042] The test results for this comparative example are shown in Table 1: Al 47.6%, O 52.4%, coating thickness 9.6µm, deposition rate 0.8µm / h. Figure 1 (b) is characterized as amorphous aluminum oxide; such as Figure 3 and Figure 4 As shown, the breakdown strength of the coating was tested to be 46 kV / mm, and the insulation resistance at 500℃ was 6.3kΩ.

[0043] Comparative Example 2 The high-deposition-efficiency alumina coating of this comparative example is prepared by the same method as in Example 1, except for the deposition conditions. The deposition conditions of this comparative example 2 are as follows: The distance between the Al metal target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 Pa, heating temperature 500℃, deposition time 12h, bias power supply -60V, Al metal target uses DC power supply, sputtering power control 150 W, argon flow rate 20 sccm, oxygen flow rate 10 sccm, argon gas purity ≥99.999%, after sputtering, cool to 50℃.

[0044] The test results for this comparative example are shown in Table 1: Al 38.7%, O 61.3%, coating thickness 1.08 µm, deposition rate 0.09 µm / h; Figure 1 As shown in (c), the coating is θ-type alumina, which exhibits better crystallinity when the oxygen content is high; as Figure 3 and Figure 4 As shown, the breakdown strength of the coating was tested to be 135 kV / mm, and the insulation resistance at 500°C was 855 kΩ. Compared to Example 1, Comparative Example 2 has better insulation performance, but the deposition efficiency is significantly reduced.

[0045] Example 2 An alumina-based coating that combines high-temperature insulation and wear resistance is prepared by introducing Cr into the coating based on Example 1 to control the phase composition. The preparation method is as follows: (1) Polish the dispersed copper block substrate or conductive tip sample with 1000# sandpaper on one side. After polishing, clean the sample with deionized water and anhydrous ethanol for 25 minutes in sequence. After cleaning, dry it with nitrogen and fix the dispersed copper substrate on the sample tray. (2) Install the dispersed copper substrate sample disk in the chamber of the magnetron sputtering instrument, attach the block dispersed copper to the substrate using high temperature adhesive, close the chamber door and sequentially perform high vacuum, substrate heating, argon, oxygen and nitrogen gas introduction, adjust the deposition gas pressure, open the substrate baffle, turn on the power and perform coating deposition, use Al target and Cr target as target materials, use the DC reactive sputtering deposition method of magnetron sputtering technology to obtain the coating, after the temperature cools down, take out the coating sample and store it in a vacuum environment to obtain the block dispersed copper and the surface coating of the conductive nozzle.

[0046] The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 The sputtering process was carried out at 500°C for 12 hours, with a bias power supply of -60V. Both Al and Cr targets used DC power supplies. The sputtering power of the Al target was controlled at 150W, and the sputtering power of the Cr target was controlled at 100W. The argon flow rate was 20 sccm, the oxygen flow rate was 2 sccm, and the argon gas purity was ≥99.999%. After sputtering, the temperature was cooled to 50°C.

[0047] Table 2 shows the composition, thickness, and deposition efficiency of the coatings prepared in Example 2 and Comparative Examples 3-4. The test results of this embodiment are shown in Table 2: Al 28.4%, Cr 13.2%, O 58.4%, coating thickness 5.04µm, and deposition rate 0.42µm / h. Figure 6 The XRD pattern shows the coating as an α-(Al,Cr)₂O₃ phase, indicating that the introduction of Cr lowers the nucleation barrier of the α phase, transforming the θ phase into the α phase and improving the insulation performance. Figure 7 and Figure 8 ).

[0048] Comparative Example 3 The high-deposition-efficiency alumina coating of this comparative example is prepared by the same method as in Example 2, except for the deposition conditions. The deposition conditions of this comparative example 3 are as follows: The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 Pa, heating temperature 500℃, deposition time 12h, bias power supply -60V, Al and Cr targets use DC power supply, Al target sputtering power controlled at 150W, Cr target sputtering power controlled at 60W, argon flow rate 20 sccm, oxygen flow rate 2 sccm, argon gas purity ≥99.999%, after sputtering, cooling to 50℃.

[0049] The detection results of this comparative example are shown in Table 2: Al 36.7%, Cr 5.5%, O 57.8%, coating thickness 4.68µm, and deposition rate 0.39µm / h. The XRD pattern shows the simultaneous presence of α-(Al,Cr)₂O₃ and θ-(Al,Cr)₂O₃ phases in the coating, indicating that the low Cr content is insufficient to generate pure α-(Al,Cr)₂O₃.

[0050] Comparative Example 4 The high-deposition-efficiency alumina coating of this comparative example is prepared by the same method as in Example 2, except for the deposition conditions. The deposition conditions of this comparative example 4 are as follows: The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 The sputtering process was carried out at 500°C for 12 hours, with a bias power supply of -60V. Both Al and Cr targets used DC power supplies. The sputtering power of the Al target was controlled at 150W, and the sputtering power of the Cr target was controlled at 160W. The argon flow rate was 20 sccm, the oxygen flow rate was 2 sccm, and the argon gas purity was ≥99.999%. After sputtering, the temperature was cooled to 50°C.

[0051] The test results for this comparative example are shown in Table 2: Al 21.7%, Cr 20.6%, O 57.7%, coating thickness 5.52 µm, deposition rate 0.46 µm / h. XRD patterns show the formation of the α-(Al,Cr)₂O₃ phase in the coating. The diffraction peaks are shifted at smaller angles relative to the previous example. Since the band gap of chromium oxide is lower than that of aluminum oxide, the excessive Cr leads to a decrease in insulation performance. Figure 7 and Figure 8 ). Figure 5 The surface and cross-sectional morphology of the coatings prepared in Example 1 and Comparative Examples 1-2 after 10 hours at 500°C; wherein Example 1 is Al 43.2 O 56.8 Comparative Example 1 is Al 47.6 O 52.4 Comparative Example 2 is Al 38.7 O 61.3 .

[0052] Example 3 An alumina-based coating that combines high-temperature insulation and wear resistance is prepared as follows: (1) Polish the dispersed copper block substrate or conductive tip sample with 1000# sandpaper on one side. After polishing, clean the sample with deionized water and anhydrous ethanol for 25 minutes in sequence. After cleaning, dry it with nitrogen and fix the dispersed copper substrate on the sample tray. (2) Install the dispersed copper substrate sample disk in the chamber of the magnetron sputtering instrument, attach the block dispersed copper to the substrate using high temperature adhesive, close the chamber door and sequentially perform high vacuum, substrate heating, argon, oxygen and nitrogen gas introduction, adjust the deposition gas pressure, open the substrate baffle, turn on the power and perform coating deposition, use Al target and Cr target as target materials, use the DC reactive sputtering deposition method of magnetron sputtering technology to obtain the coating, after the temperature cools down, take out the coating sample and store it in a vacuum environment to obtain the block dispersed copper and the surface coating of the conductive nozzle.

[0053] The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 The heating temperature was 500℃, the deposition time was 15 h, the bias power supply was -60V, the Al and Cr targets used DC power supplies, the sputtering power of the Al target was controlled at 150W, the sputtering power of the Cr target was controlled at 100W, the argon-oxygen mixture (argon-oxygen ratio 99:1) flow rate was 30 sccm, the nitrogen flow rate was 10 sccm, and after sputtering was completed, the temperature was cooled to 50℃.

[0054] Table 3 shows the composition, thickness, and deposition efficiency of the coatings prepared in Example 3 and Comparative Examples 5-6.

[0055] The test results of this embodiment are shown in Table 3: Al 26.4%, Cr 13.2%, O 53.6%, N 6.8%, coating thickness 7 µm, deposition rate 0.46 µm / h. The introduction of N compensates for the oxygen vacancy defects caused by high-speed deposition in Example 1, thus improving the insulation performance. Figure 11 and Figure 12 ) The coating phase in this embodiment is a two-phase structure composed of corundum-type AlCrON and CrN. Figure 9 The introduction of Cr induced the formation of the α phase, while the introduction of N formed a two-phase structure that further improved mechanical properties through solid solution strengthening. The corundum phase provides high hardness, exhibiting compressive and cutting resistance, while the CrN phase provides better toughness and reduces wear rate. Figure 13 ).

[0056] like Figure 10 AlCrON 11.5 As shown in Example 3, the coating of this application has a smooth and flat surface and a dense coating before and after high temperature.

[0057] like Figure 11 The breakdown resistance of coatings with different nitrogen contents shows that an appropriate amount of N improves the breakdown resistance of the coating.

[0058] Comparative Example 5 The high-deposition-efficiency alumina coating of this comparative example is prepared by the same method as in Example 3, except for the deposition conditions. The deposition conditions of this comparative example 5 are as follows: The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 The heating temperature was 500℃, the deposition time was 15 h, the bias power supply was -60V, the Al and Cr targets used DC power supplies, the sputtering power of the Al target was controlled at 150W, the sputtering power of the Cr target was controlled at 100W, the argon-oxygen mixture (argon-oxygen ratio 99:1) flow rate was 30 sccm, the nitrogen flow rate was 6 sccm, and after sputtering was completed, the temperature was cooled to 50℃.

[0059] The test results of this comparative example are shown in Table 3: Al 25.01%, Cr 12.8%, O 56.39%, N 5.3%, the coating thickness is 6.3 µm, and the deposition rate is 0.42 µm / h.

[0060] like Figure 10 AlCrON 5.3 As shown in Comparative Example 5, the coating of Comparative Example 5 has a smooth and flat surface before and after high temperature, and the coating is dense.

[0061] like Figure 13 AlCrON 5.3 The friction and wear of (Comparative Example 5) shows that Comparative Example 5 has a larger wear depth and a higher wear rate. When the N content is only 5.3%, the structure is mainly composed of hard and brittle oxides, lacking sufficient toughness of the CrN phase, which leads to a high wear rate.

[0062] Comparative Example 6 The high-deposition-efficiency alumina coating of this comparative example is prepared by the same method as in Example 3, except for the deposition conditions. The deposition conditions of this comparative example 6 are as follows: The distance between the Al / Cr combined target and the substrate is 6 mm, and the back-floor vacuum is 7 × 10⁻⁶. -4 The heating temperature was 500℃, the deposition time was 15h, the bias power supply was -60V, the Al and Cr targets used DC power supplies, the sputtering power of the Al target was controlled at 150W, the sputtering power of the Cr target was controlled at 100W, the argon-oxygen mixture (argon-oxygen ratio 99:1) flow rate was 30 sccm, the nitrogen flow rate was 16 sccm, and after sputtering was completed, the temperature was cooled to 50℃.

[0063] The test results of this comparative example show that: Al 27.0%, Cr 13.6%, O 39.2%, N 20.2%, the coating thickness is 4.96 µm, and the deposition rate is 0.33 µm / h.

[0064] like Figure 10 AlCrON 20.2 As shown in Comparative Example 6, the surface of the coating in the deposited state of Comparative Example 6 is smooth and flat, and the coating is dense, but the coating cracks after prolonged high temperature. Figure 10 ).

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-temperature insulating and wear-resistant coating, characterized in that, The steps are as follows: (1) The surface of the dispersed copper substrate is polished, then ultrasonically cleaned with acetone, and dried to obtain the pretreated dispersed copper substrate; (2) Pretreatment of the dispersed copper substrate: Using magnetron sputtering technology, Al and Cr targets are used as targets for coating deposition. After cooling, an alumina-based dual-phase coating is obtained, namely a high-temperature insulating and wear-resistant coating.

2. The method for preparing the high-temperature insulating and wear-resistant coating according to claim 1, characterized in that: The grinding and polishing process uses 600#-2000# sandpaper for single-sided grinding and polishing. After grinding and polishing, the dispersed copper substrate is ultrasonically cleaned with deionized water and anhydrous ethanol for 20-30 minutes in sequence.

3. The method for preparing the high-temperature insulating and wear-resistant coating according to claim 2, characterized in that: The distance between the Al target and the Cr target and the pretreated dispersed copper substrate is 6 mm.

4. The method for preparing the high-temperature insulating and wear-resistant coating according to claim 2, characterized in that, The coating deposition conditions were as follows: backplane vacuum of 6.4 × 10⁻⁶. -4 - 7.5×10 -4 The heating temperature is 500 ℃, the deposition time is 12-18h, the bias power supply power is -60V~-200V, the Al metal target uses a DC power supply, the sputtering power is controlled at 100~200W, the flow rate of argon-oxygen mixture is 30 sccm, the flow rate of nitrogen is 8.5~11.5 sccm; the temperature after cooling is 50~60 ℃.

5. The method for preparing the high-temperature insulating and wear-resistant coating according to claim 4, characterized in that: The volume ratio of argon to oxygen in the argon-oxygen mixture is 99:

1.

6. The high-temperature insulating and wear-resistant coating prepared by the method according to any one of claims 1-5, characterized in that: The high-temperature insulating and wear-resistant coating contains 24.5%–28.4% Al, 10.2%–15.3% Cr, 48.8%–52.3% O, and 10.6%–12.5% ​​N.

7. The high-temperature insulating and wear-resistant coating according to claim 6, characterized in that: The high-temperature insulating and wear-resistant coating has a two-phase structure composed of corundum-type AlCrON and CrN.

8. A method for preparing a high-temperature insulating welding conductive tip, characterized in that, The steps are as follows: refer to the method described in any one of claims 1-5, and replace the dispersed copper substrate with a welding conductive tip.

9. A high-temperature insulating welding conductive tip prepared using the method of claim 8.

10. The application of the high-temperature insulating and wear-resistant coating of claim 7 in the field of welding conductive tip protection.

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