A high-conductivity, corrosion-resistant composite coating and its preparation method

Abstract

The present invention discloses a highly conductive and corrosion-resistant composite coating and a preparation method thereof, the preparation method comprising: pre-treating the surface of a metal substrate, then clamping it in a vacuum chamber of a coating machine, baking the exhaust under a vacuum state, and then performing nitriding treatment on the surface of the metal substrate to form a nitriding layer with a thickness of 0.1-1 μm; then sequentially depositing pure metal and the nitride of the above-mentioned metal to form a base layer with a total thickness of 0.02-0.5 μm; then sequentially depositing two metals and the nitride of the above-mentioned two metals to form an intermediate layer with a total thickness of 0.02-1.5 μm; then depositing a metal-doped TAC layer with a thickness of 0.03-1 μm to obtain a composite coating with a total thickness of 0.17-3.5 μm. The present invention adopts element doping modification and multi-layer composite structure to improve the density of the coating while giving play to the excellent performance of the metal nitride and the amorphous carbon layer, so that the obtained coating thickness is thin, corrosion resistance and conductivity are good.

Description

Technical Field

[0001] The present invention relates to the technical field of material surface treatment, and in particular to a high-conductivity, corrosion-resistant composite coating and a preparation method thereof. Background Art

[0002] Metals and their alloys play a vital role in industry. However, factors such as solutions and electrical currents in the operating environment can corrode metal materials, causing various performance failures. This can lead to significant economic losses, catastrophic accidents, energy waste, and environmental pollution. For example, in the new energy sector, battery energy conversion efficiency and service life are crucial performance indicators. Metals, due to their excellent machinability, mechanical properties, and electrical conductivity, are the preferred materials for key battery components such as plates and current collectors. However, in the acidic solutions and electrochemical working environments of batteries, metal components are highly susceptible to corrosion, which can damage their functional structures. The metal ions produced by corrosion also reduce the battery's energy conversion efficiency and service life. In the 3C industry, due to the complex and ever-changing operating environments of electronic products, their metal components are often corroded by various solutions, reducing their conductivity and causing electrostatic discharge and electromagnetic interference. These can cause electronic product failure at best, or even lead to insulation breakdown and explosion.

[0003] As a result, a large number of coating technologies for surface modification and protection of metal materials have emerged, such as metal nitride coatings such as CrN, TiN, NbN, and amorphous carbon coatings (DLC). These methods effectively improve the electrochemical corrosion resistance and interfacial conductivity of metal materials. However, metal nitride coatings often have a very obvious columnar crystal structure, and the gaps between the columnar crystals can easily become channels for corrosive ions, which has a poor protective effect on the substrate. Amorphous carbon coatings have defects such as hydrophilicity, poor toughness, and high internal stress, which limit the corrosion resistance of their advantages. In order to avoid the occurrence of the above situation, the thickness of the coating structure design is often above 500nm, and the problems of low production process efficiency and unbalanced overall performance have led to an increase in production costs and production delivery cycles, which is not conducive to industrial production and the actual application of products.

[0004] A Chinese patent application document with publication number CN115911436A discloses a process for preparing a carbon-based composite coating for a metal bipolar plate of a PEM fuel cell, comprising the following steps: baking and degassing the surface of the bipolar plate to be plated, ion cleaning and activation, preparing an ion-diffused layer, depositing a metal base layer, depositing a metal nitride layer, depositing a DLC layer, and depositing a Ta-C layer in a vacuum state. It combines ion nitriding / carburizing, magnetron sputtering MS, plasma-enhanced chemical vapor deposition PECVD, and pure ion plating PIC to prepare a carbon-based composite coating on a metal bipolar plate, which can improve the corrosion resistance and bonding strength of the bipolar plate and extend its service life. However, the coating is still relatively thick, the coating deposition time is long, and there are many composite processes, which is not conducive to industrial production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is how to efficiently improve the electrical conductivity and corrosion resistance of the metal coating.

[0006] The present invention solves the above technical problems through the following technical means:

[0007] A method for preparing a highly conductive and corrosion-resistant composite coating comprises the following steps:

[0008] S1. Pre-treat the surface of the metal substrate, then clamp it in the vacuum chamber of the coating machine and bake and exhaust it under vacuum;

[0009] S2. Performing ion beam cleaning on the metal substrate after baking exhaust;

[0010] S3, performing nitriding treatment on the metal substrate after ion beam cleaning to form a nitrided layer on the surface of the metal substrate; wherein the thickness of the nitrided layer is 0.1-1 μm;

[0011] S4, depositing pure metal and the nitride of the metal in sequence on the surface of the metal substrate treated in S3 to form a base layer; wherein the total thickness of the base layer is 0.02-0.5 μm;

[0012] S5. Depositing two metals and nitrides of the two metals on the surface of the base layer formed in S4 in sequence to form an intermediate layer; wherein the total thickness of the intermediate layer is 0.02-1.5 μm;

[0013] S6. Depositing a metal-doped TAC layer on the surface of the intermediate layer formed in S5 to obtain the highly conductive and corrosion-resistant composite coating, wherein the thickness of the metal-doped TAC layer is 0.03-1 μm, and the total thickness of the obtained composite coating is 0.17-3.5 μm.

[0014] Preferably, in S1, the pretreatment of the metal substrate surface comprises the following steps: in a dust-free environment, the metal substrate is cleaned with detergent and deionized water in sequence, and then ultrasonically cleaned in anhydrous ethanol; after cleaning, the metal substrate is placed in a depassivation film solution at 70-90°C and soaked for 20-40 minutes; the metal substrate is ultrasonically cleaned in deionized water again, and then air-dried with nitrogen; during the baking exhaust process, the metal substrate is vacuumed to 1×10 -2 Pa below, the baking temperature is 200-350 ° C, the time is 30-120 min; in S2, the specific steps include: vacuuming to 7×10 -3 Pa and maintain the temperature at 200-350℃, start the turntable to rotate at a uniform speed, then fill it with argon, the argon partial pressure is 0.2-0.8Pa, then turn on the ion source power supply and the turntable bias power supply, the ion source voltage is 200-1200V, the current is 0.5-2A, the turntable bias is 500-2000V, the bias current is 0.5-2A, the bias duty cycle is set to 50-80%, and the metal substrate surface is evenly cleaned for 20-180 minutes.

[0015] Preferably, in S3, the steps are specifically included: after ion beam cleaning, turn off the argon gas, maintain the temperature at 200-350°C, keep the rotating rack rotating at a constant speed, and evacuate to 7×10 -3 Pa, nitrogen is introduced to maintain the nitrogen partial pressure between 5-20Pa; then nitriding treatment is carried out. During the nitriding treatment, two sets of power supplies, DC power supply and AC power supply, are used. The AC turntable bias voltage is 1200-2000V, the DC turntable voltage is 900-1500V, the AC turntable bias current is 3-7A, the DC turntable bias current is 3-7A, and the nitriding time is 30-120min to form a nitriding layer on the surface of the metal substrate.

[0016] Preferably, in S4, the pure metal includes one metal or two metals; the one metal is one of Ti, Cr, Nb, Zr, and Ta; the two metals are one of Ni and Cr, or Al and Cr; the metal nitride is one of TiN, CrN, NbN, ZrN, TaN, NiCrN, and AlCrN; in S5, the two deposited metals are one of Cr and Mo, or Zr and Mo; the metal nitride is one of CrMoN and ZrMoN; in S6, the doped metal is one or more of Ti, Cr, and Zr.

[0017] Preferably, in S4, the steps are specifically included: turning off the nitrogen, turning off the bias voltage of the rotating frame, maintaining the temperature at 200-350°C, keeping the rotating frame rotating at a constant speed, and evacuating to 2×10 -3Pa, fill with argon, the argon partial pressure is 0.1-3Pa, start magnetron sputtering of metal to form a metal base layer, set the sputtering power to 2-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 5-40min, and complete the sputtering of the metal base layer; then introduce nitrogen to maintain the gas pressure at 0.1-3Pa, start magnetron sputtering of metal nitride to form a metal nitride base layer, set the sputtering power to 2-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 5-120min, and complete the sputtering of the metal nitride base layer to form a base layer.

[0018] Preferably, in S5, the steps are as follows: turning off the nitrogen, turning off the bias voltage of the rotating frame, maintaining the temperature at 200-350°C, keeping the rotating frame rotating at a constant speed, and evacuating the vacuum to 2×10 -3 Pa, fill with argon, the argon partial pressure is 0.1-3Pa, start co-sputtering of the two metals to form a metal intermediate layer, set the metal target sputtering power to 1-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 10-60min, and complete the co-sputtering of the metal intermediate layer; then introduce nitrogen to maintain the gas pressure at 0.1-3Pa, set the metal target sputtering power to 1-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, and the sputtering time to 10-120min to complete the sputtering of the metal nitride intermediate layer.

[0019] Preferably, in S6, the steps are specifically included: turning off the nitrogen and argon gas, turning off the sputtering system and the heating system, waiting for the temperature to drop below 120°C, turning on the multi-arc ion plating system, and evacuating to 3×10 -4 Pa, start multi-arc ion plating, the carbon target arc current is 50-150A, the metal target arc current is 50-150A, the turntable bias is 100-2000V, and the time is 5-60min.

[0020] Preferably, S5 further includes repeatedly depositing two metals and nitrides of the two metals to form n intermediate layers; wherein n is less than or equal to 50.

[0021] Preferably, in S4, pure metal is deposited to form a metal base layer, the thickness of the metal base layer is 0.01-0.3 μm, and metal nitride is deposited to form a metal nitride base layer, the thickness of the metal nitride base layer is 0.01-0.3 μm; in S5, two metals are deposited to form a metal intermediate layer, the thickness of the metal intermediate layer is 0.01-0.5 μm; two metal nitrides are deposited to form a metal nitride intermediate layer, the thickness of the metal nitride intermediate layer is 0.01-1 μm.

[0022] Preferably, in S1, the metal substrate is one of stainless steel, aluminum and aluminum alloys, titanium and titanium alloys, nickel and nickel alloys, copper and copper alloys, or carbon steel.

[0023] Preferably, the thickness of the nitriding layer is 0.1 μm; the total thickness of the primer layer is 0.02-0.04 μm; the total thickness of the intermediate layer is 0.02-0.06 μm; the thickness of the metal-doped TAC layer is 0.03-0.04 μm, and the total thickness of the obtained composite coating is 0.17-0.22 μm.

[0024] The present invention also provides a high-conductivity, corrosion-resistant composite coating, which is prepared by adopting the preparation method of the high-conductivity, corrosion-resistant composite coating.

[0025] The advantages of the present invention are:

[0026] The method for preparing a highly conductive, corrosion-resistant composite coating of the present invention first utilizes a DC-coupled AC cathode turret technology (i.e., dual-power nitriding, where two different types of power sources are simultaneously supplied to the turret. The present invention utilizes a combination of AC pulse and DC pulse power sources) for plasma nitriding. This optimizes the surface morphology and structure of the metal substrate, providing primary corrosion protection. Compared to conventional plasma nitriding, the DC-coupled AC cathode turret technology offers improved nitriding uniformity and higher efficiency. The base layer is prepared using magnetron sputtering technology, ensuring a good bond between the conductive, corrosion-resistant layer and the substrate. Subsequently, a metal nitride intermediate layer is formed by co-sputtering Mo with Cr or Zr. This eliminates the columnar crystal structure inherent in CrN or ZrN, reducing the coating's grain size and resulting in a denser structure. Furthermore, the co-sputtered MoN2 product exhibits excellent conductivity, effectively optimizing the structural defects of the metal nitride. While maintaining high conductivity, the dense structure effectively prevents corrosive ions from contacting the metal substrate, providing secondary protection. As the hardest amorphous carbon, TAC has good corrosion resistance, but because it contains a large amount of diamond-like structure, it has great internal stress, which may cause film failure and peeling. TAC coating modified by Cr, Zr, Ti single doping or co-doping will produce nanophases such as CrC, ZrC, and TiC. These phases have good hydrophobicity and conductivity, which is conducive to the exclusion of corrosive solutions, and can effectively reduce the internal stress of the coating, maintain the dense structure of amorphous carbon, prevent the generation of defects and other diffusion channels of corrosive ions, and achieve third-level protection. The method of the present invention adopts element doping modification and multi-layer composite structure, which can improve the density of the coating while giving play to the excellent performance of the metal nitride and amorphous carbon layer, so that the obtained coating is thin, corrosion-resistant and conductive. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1This is a schematic flow chart of the method for preparing the highly conductive and corrosion-resistant composite coating provided in Example 1 of the present invention;

[0028] Figure 2 A schematic structural diagram of a highly conductive, corrosion-resistant composite coating provided in Example 2 of the present invention;

[0029] Figure 3 1. It is an assembly diagram of a power supply used in the nitriding process according to an embodiment of the present invention;

[0030] Figure 2 Description of main symbols:

[0031] 1. Metal substrate after nitriding; 1-1. Metal substrate; 1-2. Nitrided layer; 2. Primer layer; 2-1. Metal primer layer; 2-2. Metal nitride primer layer; 3. Intermediate layer; 3-1. Metal intermediate layer; 3-2. Metal nitride intermediate layer; 4. Metal-doped TAC layer.

[0032] Figure 3 Description of main symbols:

[0033] 1. AC cathode plate; 2. DC cathode plate; 3. DC cathode conductive support rod; 4. AC cathode conductive support rod; 5. DC cathode connector; 6. AC cathode connector; 7. Insulation sleeve.

[0034] Figure 4 This is a test diagram of the acidic corrosion current density of the coatings prepared in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0036] Unless otherwise specified, the test materials and reagents used in the following examples can be obtained from commercial sources.

[0037] If no specific techniques or conditions are specified in the examples, they can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions.

[0038] In the embodiment and comparative example, the DC coupled AC cathode rotating rack technology used in the nitriding process specifically uses two sets of AC and DC power supplies for nitriding treatment, and the assembly relationship thereof is as follows: Figure 3As shown, 1 is an AC cathode plate; 2 is a DC cathode plate; 3 is a DC cathode conductive support rod; 4 is an AC cathode conductive support rod; 5 is a DC cathode connector; 6 is an AC cathode connector; 7 is an insulating sleeve; the AC cathode plate 1 is connected to the AC cathode conductive support rod 4, the negative pole of the AC pulse power supply is connected to the AC cathode connector 6, and the positive pole of the power supply is connected to the vacuum chamber of the coating machine; the DC cathode plate 2 is connected to the DC cathode conductive support rod 3, the negative pole of the DC pulse power supply is connected to the DC cathode connector 5, and the positive pole of the power supply is connected to the vacuum chamber of the coating machine; the two sets of cathode plates are parallel to each other, and the two sets of cathode systems are insulated from each other by the insulating sleeve 7.

[0039] The passivation film removal solution is a mixed solution containing HNO3 and HF, wherein the volume fraction of HNO3 is 8% and the volume fraction of HF is 2%.

[0040] Example 1

[0041] Combine Figure 1 , a flow chart of a method for preparing a highly conductive and corrosion-resistant composite coating, wherein the highly conductive and corrosion-resistant composite coating is prepared on the surface of stainless steel (metal substrate), namely, ion nitriding, deposition of a base layer, deposition of an intermediate layer, and deposition of a metal-doped TAC layer are sequentially performed on the stainless steel surface, specifically comprising the following steps:

[0042] S1. Pre-treat the surface of the metal substrate in a dust-free environment; then clamp the metal substrate in the vacuum chamber of the coating machine and bake and exhaust it under vacuum, which specifically includes the following steps: in a dust-free environment, wash the metal substrate to be coated with detergent and deionized water in sequence, and then put it into anhydrous ethanol for ultrasonic cleaning; after the cleaning is completed, put the metal substrate into a 70°C passivation film removal solution and soak it for 30 minutes; put the metal substrate into deionized water for ultrasonic cleaning again, and then put it into a nitrogen cabinet for nitrogen air drying, and the pre-treatment is completed; clamp the pre-treated metal substrate into the turntable of the vacuum chamber of the coating machine and evacuate to 1×10 -2 Pa, start the heating system to heat the temperature in the cavity to 250℃ and bake for 60 minutes.

[0043] S2, ion beam cleaning of the baked metal substrate, specifically including the following steps: vacuuming to 7×10 -3 Pa and maintain the temperature at 250℃, start the turntable and rotate it at a uniform speed, then fill it with argon, the argon partial pressure is 0.4Pa, then turn on the ion source power supply and turntable bias power supply, the ion source voltage is 800V, the current is 1A, the turntable bias is 1000V, the bias current is 1A, the bias duty cycle is set to 70%, and the metal substrate surface is evenly cleaned for 30 minutes.

[0044] S3, filling the vacuum chamber with nitrogen to perform nitriding treatment on the metal substrate, specifically including the following steps: after ion beam cleaning, turn off the argon gas, maintain the temperature at 250 ° C, keep the rotating frame rotating at a constant speed, and evacuate to 7×10 -3 Pa, nitrogen was introduced, maintaining a nitrogen partial pressure of 15 Pa. Nitriding was initiated using a DC-coupled AC cathode turret technique. The bias current was activated, with the AC turret bias voltage set to 2000V, the DC turret voltage to 1500V, the AC turret bias current to 3A, and the DC turret bias current to 3A. The ion nitriding time was 30 minutes. A 0.1μm thick nitrided layer was formed on the metal substrate surface.

[0045] S4, depositing pure metal and its metal nitride on the surface of the nitrided metal substrate to form a base layer, the metal selected is Cr; the metal nitride selected is CrN; the specific deposition steps of the base layer are: turning off the nitrogen, turning off the bias of the turntable, maintaining the temperature at 250 ° C, keeping the turntable rotating at a constant speed, and evacuating to 2×10 -3 Pa, fill with argon gas, and the argon partial pressure is 0.2Pa. Start magnetron sputtering Cr to form a metal base layer, set the sputtering power to 5KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 5min, and complete the sputtering of the metal base layer. Then introduce nitrogen gas to maintain the gas pressure at 0.5Pa, set the sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the sputtering of the metal nitride base layer. Form a (10nm thick Cr + 10nm thick CrN) base layer on the surface of the nitriding layer.

[0046] S5. Deposit two metals and their metal nitrides on the surface of the base layer to form an intermediate layer; the metals are Cr and Mo; the metal nitride is CrMoN; the specific steps of depositing the intermediate layer are: turn off the nitrogen, turn off the bias of the turntable, maintain the temperature at 250°C, keep the turntable rotating at a constant speed, and evacuate to 2×10 -3 Pa, fill with argon, and the argon partial pressure is 0.2Pa. Start co-sputtering Cr and Mo, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the co-sputtering of the metal intermediate layer. Then introduce nitrogen to maintain the gas pressure at 0.5Pa, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 15min, and complete the sputtering of the metal nitride intermediate layer. Form an intermediate layer (10nm thick CrMo + 10nm thick CrMoN) on the surface of the base layer.

[0047] S6. Depositing a metal-doped TAC layer on the surface of the intermediate layer. The doping metal element of the metal-doped TAC layer is Cr. The specific deposition steps of the metal-doped TAC layer are as follows: turning off the nitrogen and argon gas, turning off the sputtering system and the heating system, waiting for the temperature to drop to 60°C, connecting the multi-arc ion plating system, and evacuating to 3×10 -4 Pa or less. Multi-arc ion plating was initiated with a carbon target arc current of 60 A, a Cr target arc current of 70 A, a turret bias of 300 V, and a duration of 5 minutes. The metal-doped TAC layer was deposited to a thickness of 30 nm.

[0048] Example 2

[0049] Combine Figure 2 , a schematic structural diagram of a highly conductive and corrosion-resistant composite coating, wherein a highly conductive and corrosion-resistant composite coating is prepared on the surface of stainless steel (metal substrate) 1-1, namely, ion nitriding is sequentially performed on the surface of the stainless steel 1-1 to form a nitrided metal substrate 1, a base layer 2 is deposited, an intermediate layer 3 is deposited, and a metal-doped TAC layer 4 is deposited, specifically comprising the following steps:

[0050] S1. Pre-treat the surface of the stainless steel substrate 1-1 in a dust-free environment; then clamp the stainless steel substrate 1-1 in the vacuum chamber of the coating machine and bake and exhaust under vacuum; specifically, the following steps: in a dust-free environment, wash the stainless steel substrate 1-1 to be coated with detergent and deionized water in sequence, and then place it in anhydrous ethanol for ultrasonic cleaning; after cleaning, place the stainless steel substrate 1-1 in a 70°C depassivation film solution and soak it for 30 minutes; place the stainless steel substrate 1-1 in deionized water for ultrasonic cleaning again, and then place it in a nitrogen cabinet for nitrogen air drying, and the pre-treatment is completed; clamp the pre-treated stainless steel substrate 1-1 on the turntable of the vacuum chamber of the coating machine, and evacuate to 1×10 -2 Pa, start the heating system to heat the temperature in the cavity to 250℃ and bake for 60 minutes.

[0051] S2, ion beam cleaning is performed on the baked stainless steel substrate 1-1, specifically comprising the following steps: vacuuming to 7×10 -3 Pa and maintain the temperature at 250℃, start the turntable and rotate it at a uniform speed, then fill it with argon, the argon partial pressure is 0.4Pa, then turn on the ion source power supply and the turntable bias power supply, the ion source voltage is 800V, the current is 1A, the turntable bias is 1000V, the bias current is 1A, the bias duty cycle is set to 70%, and the surface of the stainless steel substrate 1-1 is evenly cleaned for 30 minutes.

[0052] S3, filling the vacuum chamber with nitrogen to perform nitriding treatment on the stainless steel substrate 1-1, specifically including the following steps: after ion beam cleaning, turning off the argon gas, maintaining the temperature at 250°C, keeping the rotating frame rotating at a constant speed, and evacuating to 7×10 -3 Pa, nitrogen gas was introduced, maintaining a nitrogen partial pressure of 15 Pa. Nitriding was initiated using a DC-coupled AC cathode turret technique. The bias current was activated, with the AC turret bias voltage set to 2000V, the DC turret voltage to 1500V, the AC turret bias current to 3A, and the DC turret bias current to 3A. The ion nitriding time was 30 minutes. A 0.1 μm thick nitrided layer 1-2 was formed on the surface of the stainless steel substrate 1-1, resulting in the nitrided stainless steel substrate 1.

[0053] S4, depositing pure metal and its metal nitride on the surface of the nitrided stainless steel substrate 1 to form a base layer 2; the metal is Cr; the metal nitride is CrN; the specific deposition steps of the base layer 2 are: turn off the nitrogen, turn off the bias of the turntable, maintain the temperature at 250 ° C, keep the turntable rotating at a constant speed, and evacuate to 2×10 -3 Pa, fill with argon, and the argon partial pressure is 0.3Pa. Start magnetron sputtering Cr to form metal base layer 2-1, set the sputtering power to 5KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 5min, and complete the sputtering of metal base layer 2-1. Then introduce nitrogen to maintain the gas pressure at 0.6Pa, set the sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the sputtering of metal nitride base layer 2-2. Form (10nm thick Cr + 10nm thick CrN) base layer 2 on the surface of the nitriding layer 1-2.

[0054] S5. Deposit two metals and their metal nitrides on the surface of the base layer 2 to form an intermediate layer 3; the metals are Cr and Mo; the metal nitride is CrMoN; the intermediate layer 3 includes three periodic coatings. The specific deposition steps of the intermediate layer 3 are as follows: turn off the nitrogen, turn off the bias voltage of the rotating frame, maintain the temperature at 250°C, keep the rotating frame rotating at a constant speed, and evacuate to 2×10 -3Pa, fill with argon gas, and the argon partial pressure is 0.3Pa. Start co-sputtering Cr and Mo to form the metal intermediate layer 3-1, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the co-sputtering of the metal intermediate layer 3-1. Then introduce nitrogen gas to maintain the gas pressure at 0.6Pa, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 15min, and complete the sputtering of the metal nitride intermediate layer 3-2. Repeat the steps of depositing the metal intermediate layer 3-1 and the metal nitride intermediate layer 3-2 three times. Form (10nm thick CrMo + 10nm thick CrMoN) × 3 intermediate layers 3 on the surface of the base layer 2.

[0055] S6, depositing a metal-doped TAC layer 4 on the surface of the intermediate layer 3; the doping metal element of the metal-doped TAC layer 4 is selected as Cr, and the specific deposition steps of the metal-doped TAC layer 4 are as follows: turning off the nitrogen and argon gas, turning off the sputtering system and the heating system, waiting for the temperature to drop to 60°C, connecting the multi-arc ion plating system, and evacuating to 3×10 -4 Pa or less. Multi-arc ion plating was started with a carbon target arc current of 60 A, a Cr target arc current of 70 A, a turret bias of 300 V, and a duration of 5 minutes. The metal-doped TAC layer 4 was deposited to a thickness of 30 nm.

[0056] Example 3

[0057] Titanium alloy is selected as the metal matrix, that is, ion nitriding, depositing a base layer, depositing an intermediate layer, and depositing a metal-doped TAC layer are sequentially performed on the surface of the titanium alloy, specifically including the following steps:

[0058] S1. Pre-treat the surface of the titanium alloy substrate in a dust-free environment; then clamp the titanium alloy substrate in the vacuum chamber of the coating machine and bake and exhaust it under vacuum, specifically including the following steps: in a dust-free environment, wash the titanium alloy substrate to be coated with detergent and deionized water in succession, and then put it into anhydrous ethanol for ultrasonic cleaning; after cleaning, put the titanium alloy substrate into a 70°C depassivation film solution and soak it for 20 minutes; put the titanium alloy substrate into deionized water for ultrasonic cleaning again, and then put it into a nitrogen cabinet for nitrogen air drying, and the pre-treatment is completed; clamp the pre-treated titanium alloy substrate into the turntable of the vacuum chamber of the coating machine, and evacuate to 1×10 -2 Pa, start the heating system to heat the temperature in the cavity to 300℃ and bake for 60 minutes.

[0059] S2, ion beam cleaning is performed on the baked titanium alloy substrate, specifically including the following steps: vacuuming to 7×10 -3 Pa and maintain the temperature at 300 ° C, start the turntable to rotate at a uniform speed, then fill it with argon, the argon partial pressure is 0.3 Pa, then turn on the ion source power supply and turntable bias power supply, the ion source voltage is 600 V, the current is 1 A, the turntable bias is 1500 V, the bias current is 0.5 A, the bias duty cycle is set to 65%, and the surface of the titanium alloy substrate is evenly cleaned for 40 minutes.

[0060] S3, filling nitrogen into the vacuum chamber to perform nitriding treatment on the titanium alloy substrate, specifically including the following steps: after ion beam cleaning, turning off the argon gas, maintaining the temperature at 300 ° C, keeping the rotating frame rotating at a constant speed, and evacuating to 7×10 -3 Pa, nitrogen was introduced, maintaining a nitrogen partial pressure of 13 Pa. Nitriding was initiated using a DC-coupled AC cathode turret technique. The bias current was activated, with the AC turret bias voltage set to 1600V, the DC turret voltage to 1200V, the AC turret bias current to 3.5A, and the DC turret bias current to 3.5A. The ion nitriding time was 40 minutes. A 0.1μm thick nitrided layer was formed on the titanium alloy substrate surface.

[0061] S4, depositing pure metal and its metal nitride on the surface of the titanium alloy substrate after nitriding to form a base layer, the metal is Ti; the metal nitride is TiN; the specific deposition steps of the base layer are: turning off the nitrogen, turning off the bias of the turntable, maintaining the temperature at 300 ° C, keeping the turntable rotating at a constant speed, and evacuating to 2×10 -3 Pa, fill with argon gas, and the argon partial pressure is 0.3Pa. Start magnetron sputtering Ti to form a metal base layer, set the sputtering power to 5KW, the turret bias to 220V, the turret bias duty cycle to 65%, the sputtering time to 10min, and complete the sputtering of the metal base layer. Then introduce nitrogen gas to maintain the gas pressure at 0.6Pa, set the sputtering power to 5KW, the turret bias to 220V, the turret bias duty cycle to 65%, and the sputtering time to 15min. Form a (10nm thick Ti + 10nm thick TiN) base layer on the surface of the nitrided layer.

[0062] S5. Deposit two metals and their metal nitrides on the surface of the base layer to form an intermediate layer; the metals are Zr and Mo; the metal nitride is ZrMoN; the intermediate layer includes three periodic coatings, each periodic coating is composed of a metal intermediate layer and a metal nitride intermediate layer, and the specific deposition steps of the intermediate layer are as follows: turn off the nitrogen, turn off the bias voltage of the rotating frame, maintain the temperature at 300°C, keep the rotating frame rotating at a constant speed, and evacuate to 2×10 -3Pa, fill with argon gas, and the argon partial pressure is 0.3Pa. Start co-sputtering Zr and Mo to form a metal intermediate layer, set the Zr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 220V, the turret bias duty cycle to 65%, the sputtering time to 10min, and complete the co-sputtering of the metal intermediate layer. Then introduce nitrogen gas to maintain the gas pressure at 0.7Pa, set the Zr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 220V, the turret bias duty cycle to 65%, the sputtering time to 15min, and complete the sputtering of the metal nitride intermediate layer. Repeat the steps of depositing the metal intermediate layer and the metal nitride intermediate layer 3 times. Form (10nm thick ZrMo + 10nm thick ZrMoN) × 3 intermediate layers on the surface of the base layer.

[0063] S6. Depositing a metal-doped TAC layer on the surface of the intermediate layer. The doping metal element of the metal-doped TAC layer is Ti. The specific deposition steps of the metal-doped TAC layer are as follows: turning off the nitrogen and argon gas, turning off the sputtering system and the heating system, waiting for the temperature to drop to 80°C, connecting the multi-arc ion plating system, and evacuating to 3×10 -4 Pa or less. Multi-arc ion plating was initiated with a carbon target arc current of 60 A, a Ti target arc current of 60 A, a turret bias of 350 V, and a duration of 7 minutes. The metal-doped TAC layer was deposited to a thickness of 30 nm.

[0064] Example 4

[0065] A highly conductive and corrosion-resistant composite coating is prepared on the surface of stainless steel (metal substrate), that is, ion nitriding, deposition of a base layer, deposition of an intermediate layer, and deposition of a metal-doped TAC layer are sequentially performed on the stainless steel surface, specifically comprising the following steps:

[0066] S1. Pre-treat the surface of the metal substrate in a dust-free environment; then clamp the metal substrate in the vacuum chamber of the coating machine and bake and exhaust it under vacuum, which specifically includes the following steps: in a dust-free environment, wash the metal substrate to be coated with detergent and deionized water in sequence, and then put it into anhydrous ethanol for ultrasonic cleaning; after the cleaning is completed, put the metal substrate into a 70°C passivation film removal solution and soak it for 30 minutes; put the metal substrate into deionized water for ultrasonic cleaning again, and then put it into a nitrogen cabinet for nitrogen air drying, and the pre-treatment is completed; clamp the pre-treated metal substrate into the turntable of the vacuum chamber of the coating machine and evacuate to 1×10 -2 Pa, start the heating system to heat the temperature in the cavity to 250℃ and bake for 60 minutes.

[0067] S2, ion beam cleaning of the baked metal substrate, specifically including the following steps: vacuuming to 7×10 -3Pa and maintain the temperature at 250℃, start the turntable and rotate it at a uniform speed, then fill it with argon, the argon partial pressure is 0.4Pa, then turn on the ion source power supply and turntable bias power supply, the ion source voltage is 800V, the current is 1A, the turntable bias is 1000V, the bias current is 1A, the bias duty cycle is set to 70%, and the metal substrate surface is evenly cleaned for 30 minutes.

[0068] S3, filling the vacuum chamber with nitrogen to perform nitriding treatment on the metal substrate, specifically including the following steps: after ion beam cleaning, turn off the argon gas, maintain the temperature at 250 ° C, keep the rotating frame rotating at a constant speed, and evacuate to 7×10 -3 Pa, nitrogen was introduced, maintaining a nitrogen partial pressure of 15 Pa. Nitriding was initiated using a DC-coupled AC cathode turret technique. The bias current was activated, with the AC turret bias voltage set to 2000V, the DC turret voltage to 1500V, the AC turret bias current to 3A, and the DC turret bias current to 3A. The ion nitriding time was 30 minutes. A 0.1μm thick nitrided layer was formed on the metal substrate surface.

[0069] S4. Deposit pure metal and its metal nitride on the surface of the nitrided metal substrate to form a base layer. The metal is Cr; the metal nitride is CrN. The specific deposition steps of the base layer are as follows: turn off the nitrogen, turn off the bias voltage of the turntable, maintain the temperature at 250°C, keep the turntable rotating at a constant speed, and evacuate to 2×10 -3 Pa, fill with argon gas, and the argon partial pressure is 0.5Pa. Start magnetron sputtering Cr to form a metal base layer, set the sputtering power to 5KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the sputtering of the metal base layer. Then introduce nitrogen gas to maintain the gas pressure at 0.7Pa, set the sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 23min, and complete the sputtering of the metal nitride base layer. Form a (20nm thick Cr + 20nm thick CrN) base layer on the surface of the nitriding layer.

[0070] S5. Deposit two metals and their metal nitrides on the surface of the base layer to form an intermediate layer. The metals are Cr and Mo; the metal nitride is CrMoN. The specific steps for depositing the intermediate layer are as follows: turn off the nitrogen, turn off the bias voltage of the turntable, maintain the temperature at 250°C, keep the turntable rotating at a constant speed, and evacuate to 2×10 -3Pa, fill with argon, and the argon partial pressure is 0.5Pa. Start co-sputtering Cr and Mo to form a metal intermediate layer, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 20min, and complete the co-sputtering of the metal intermediate layer. Then introduce nitrogen to maintain the gas pressure at 0.7Pa, set the Cr target sputtering power to 6KW, the Mo target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 30min, and complete the sputtering of the metal nitride intermediate layer. Form an intermediate layer (20nm thick CrMo + 20nm thick CrMoN) on the surface of the base layer.

[0071] S6. Deposit a metal-doped TAC layer on the surface of the intermediate layer. The metal doping elements of the metal-doped TAC layer are Cr and Ti. The specific deposition steps of the metal-doped TAC layer are as follows: turn off the nitrogen and argon gas, turn off the sputtering system and the heating system, wait until the temperature drops to 60°C, turn on the multi-arc ion plating system, and evacuate to 3×10 -4 Pa or less. Multi-arc ion plating was initiated with a carbon target arc current of 60A, a CrTi composite target arc current of 80A, a turret bias of 300V, and a duration of 10 minutes. The metal-doped TAC layer was deposited to a thickness of 40nm.

[0072] Comparative Example 1

[0073] Compared with Example 1, the difference is that the intermediate layer is not doped with Mo, and specifically includes the following steps:

[0074] S1. Pre-treat the surface of the metal substrate in a dust-free environment; then clamp the metal substrate in the vacuum chamber of the coating machine and bake and exhaust it under vacuum, which specifically includes the following steps: in a dust-free environment, wash the metal substrate to be coated with detergent and deionized water in sequence, and then put it into anhydrous ethanol for ultrasonic cleaning; after the cleaning is completed, put the metal substrate into a 70°C passivation film removal solution and soak it for 30 minutes; put the metal substrate into deionized water for ultrasonic cleaning again, and then put it into a nitrogen cabinet for nitrogen air drying, and the pre-treatment is completed; clamp the pre-treated metal substrate into the turntable of the vacuum chamber of the coating machine and evacuate to 1×10 -2 Pa, start the heating system to heat the temperature in the cavity to 250℃ and bake for 60 minutes.

[0075] S2, ion beam cleaning of the baked metal substrate, specifically including the following steps: vacuuming to 7×10 -3Pa and maintain the temperature at 250℃, start the turntable and rotate it at a uniform speed, then fill it with argon, the argon partial pressure is 0.4Pa, then turn on the ion source power supply and turntable bias power supply, the ion source voltage is 800V, the current is 1A, the turntable bias is 1000V, the bias current is 1A, the bias duty cycle is set to 70%, and the metal substrate surface is evenly cleaned for 30 minutes.

[0076] S3, filling the vacuum chamber with nitrogen to perform nitriding treatment on the metal substrate, specifically including the following steps: after ion beam cleaning, turn off the argon gas, maintain the temperature at 250 ° C, keep the rotating frame rotating at a constant speed, and evacuate to 7×10 -3 Pa, nitrogen was introduced, maintaining a nitrogen partial pressure of 15 Pa. Nitriding was initiated using a DC-coupled AC cathode turret technique. The bias current was activated, with the AC turret bias voltage set to 2000V, the DC turret voltage to 1500V, the AC turret bias current to 3A, and the DC turret bias current to 3A. The ion nitriding time was 30 minutes. A 0.1μm thick nitrided layer was formed on the metal substrate surface.

[0077] S4, depositing pure metal and its metal nitride on the surface of the nitrided metal substrate to form a base layer, the metal selected is Cr; the metal nitride selected is CrN; the specific deposition steps of the base layer are: turning off the nitrogen, turning off the bias of the turntable, maintaining the temperature at 250 ° C, keeping the turntable rotating at a constant speed, and evacuating to 2×10 -3 Pa, fill with argon gas, and the argon partial pressure is 0.2Pa. Start magnetron sputtering Cr to form a metal base layer, set the sputtering power to 5KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 5min, and complete the sputtering of the metal base layer. Then introduce nitrogen gas to maintain the gas pressure at 0.5Pa, set the sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 10min, and complete the sputtering of the metal nitride base layer. Form a (10nm thick Cr + 10nm thick CrN) base layer on the surface of the nitriding layer.

[0078] S5. Deposit a metal and its metal nitride on the surface of the base layer to form an intermediate layer; the metal is Cr; the metal nitride is CrN; the specific steps of depositing the intermediate layer are: turn off the nitrogen, turn off the bias of the turntable, maintain the temperature at 250°C, keep the turntable rotating at a constant speed, and evacuate to 2×10 -3Pa, fill with argon gas, and the argon partial pressure is 0.2Pa. Start sputtering Cr, set the Cr target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 4min, and complete the sputtering of the metal intermediate layer. Then introduce nitrogen gas to maintain the gas pressure at 0.5Pa, set the Cr target sputtering power to 6KW, the turret bias to 180V, the turret bias duty cycle to 75%, the sputtering time to 9min, and complete the sputtering of the metal nitride intermediate layer. Form a (10nm thick Cr + 10nm thick CrN) intermediate layer on the surface of the base layer.

[0079] S6. Depositing a metal-doped TAC layer on the surface of the intermediate layer. The doping metal element of the metal-doped TAC layer is Cr. The specific deposition steps of the metal-doped TAC layer are as follows: turning off the nitrogen and argon gas, turning off the sputtering system and the heating system, waiting for the temperature to drop to 60°C, connecting the multi-arc ion plating system, and evacuating to 3×10 -4 Pa or less. Multi-arc ion plating was initiated with a carbon target arc current of 60 A, a Cr target arc current of 70 A, a turret bias of 300 V, and a duration of 5 minutes. The metal-doped TAC layer was deposited to a thickness of 30 nm.

[0080] Effect testing

[0081] The above examples and comparative examples were tested using the following method:

[0082] Corrosion resistance: Electrochemical corrosion tests were carried out in neutral salt solution and acidic solution (0.5M H2SO4+5 ppm HF), respectively. The potentiodynamic polarization curve was tested using a three-electrode system, and the corrosion current density was deduced from the Tafel curve. The lower the corrosion current density, the better the corrosion resistance.

[0083] Conductivity: The interfacial contact resistance between the sample and conductive carbon paper is measured using the voltammetric method. The sample is placed between two sheets of Toray conductive carbon paper, supported on a copper plate. During the test, a uniform pressure of 1.4 MPa is applied to the copper plate using a pressure device. The lower the contact resistance, the better the conductivity.

[0084] Hydrophobicity: The water contact angle is measured using an optical contact measuring instrument and the equipment's built-in optical analysis software. A larger water contact angle indicates better hydrophobicity, making it difficult for corrosive solutions to adhere and improving corrosion resistance.

[0085] Table 1

[0086]

[0087] From the above Table 1 and Figure 4The results show that the present invention achieves high conductivity and corrosion resistance on the surface of a metal substrate with an ultra-thin coating. The ultra-thin coating can save a lot of production costs and production cycle in industrial production, and has practical prospects for industrial application.

[0088] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a highly conductive and corrosion-resistant composite coating, characterized in that: The following steps are involved: S1. Pre-treat the surface of the metal substrate, then clamp it in the vacuum chamber of the coating machine and bake and exhaust it under vacuum; S2. Performing ion beam cleaning on the metal substrate after baking exhaust; S3, using a DC coupled AC cathode rotating rack technology to perform a nitriding treatment on the metal substrate after ion beam cleaning to form a nitriding layer on the surface of the metal substrate; wherein the thickness of the nitriding layer is 0.1-1 μm; S4. Depositing pure metal and the nitride of the above metal in sequence on the surface of the metal substrate treated in S3 to form a primer layer; wherein the total thickness of the primer layer is 0.02-0.5 μm; the pure metal comprises one metal or two metals; the one metal is one of Ti, Cr, Nb, Zr, and Ta; the two metals are one of Ni and Cr, or Al and Cr; the metal nitride is one of TiN, CrN, NbN, ZrN, TaN, NiCrN, and AlCrN; S5. Depositing two metals and nitrides of the two metals on the surface of the base layer formed in S4 in sequence to form an intermediate layer; wherein the total thickness of the intermediate layer is 0.02-1.5 μm; the two metals deposited are one of Cr and Mo, or Zr and Mo; and the metal nitride is one of CrMoN and ZrMoN; S6. Depositing a metal-doped TAC layer on the surface of the intermediate layer formed in S5 to obtain the highly conductive and corrosion-resistant composite coating, wherein the thickness of the metal-doped TAC layer is 0.03-1 μm, and the total thickness of the obtained composite coating is 0.17-3.5 μm; the doped metal is one or more of Ti, Cr, and Zr.

2. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: In S1, the metal substrate surface is pretreated, including the following steps: in a dust-free environment, the metal substrate is cleaned with detergent and deionized water in sequence, and then ultrasonically cleaned in anhydrous ethanol; after cleaning, the metal substrate is placed in a depassivation film solution at 70-90°C and soaked for 20-40 minutes; the metal substrate is ultrasonically cleaned in deionized water again, and then air-dried with nitrogen; during the baking exhaust process, the metal substrate is vacuumed to 1×10 -2 Pa below, the baking temperature is 200-350 ° C, the time is 30-120 min; in S2, the specific steps include: vacuuming to 7×10 -3 Pa and maintain the temperature at 200-350℃, start the turntable to rotate at a uniform speed, then fill it with argon, the argon partial pressure is 0.2-0.8Pa, then turn on the ion source power supply and the turntable bias power supply, the ion source voltage is 200-1200V, the current is 0.5-2A, the turntable bias is 500-2000V, the bias current is 0.5-2A, the bias duty cycle is set to 50-80%, and the metal substrate surface is evenly cleaned for 20-180 minutes.

3. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: In S3, the following steps are specifically included: after ion beam cleaning, turn off the argon gas, maintain the temperature at 200-350°C, keep the rotating frame rotating at a constant speed, and evacuate to 7×10 -3 Pa, nitrogen is introduced to maintain the nitrogen partial pressure between 5-20Pa; then nitriding treatment is carried out. During the nitriding treatment, two sets of power supplies, DC power supply and AC power supply, are used. The AC turntable bias voltage is 1200-2000V, the DC turntable voltage is 900-1500V, the AC turntable bias current is 3-7A, the DC turntable bias current is 3-7A, and the nitriding time is 30-120min to form a nitriding layer on the surface of the metal substrate.

4. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: In S4, the following steps are specifically included: turning off the nitrogen, turning off the bias voltage of the rotating frame, maintaining the temperature at 200-350°C, keeping the rotating frame rotating at a constant speed, and evacuating to 2×10 -3 Pa, fill with argon, the argon partial pressure is 0.1-3Pa, start magnetron sputtering of metal to form a metal base layer, set the sputtering power to 2-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 5-40min, and complete the sputtering of the metal base layer; then introduce nitrogen to maintain the gas pressure at 0.1-3Pa, start magnetron sputtering of metal nitride to form a metal nitride base layer, set the sputtering power to 2-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 5-120min, and complete the sputtering of the metal nitride base layer to form a base layer.

5. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: In S5, the following steps are specifically included: turning off the nitrogen, turning off the bias voltage of the rotating frame, maintaining the temperature at 200-350°C, keeping the rotating frame rotating at a constant speed, and evacuating to 2×10 -3 Pa, fill with argon, the argon partial pressure is 0.1-3Pa, start co-sputtering of the two metals to form a metal intermediate layer, set the metal target sputtering power to 1-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, the sputtering time to 10-60min, and complete the co-sputtering of the metal intermediate layer; then introduce nitrogen to maintain the gas pressure at 0.1-3Pa, set the metal target sputtering power to 1-10KW, the turret bias to 100-300V, the turret bias duty cycle to 50-80%, and the sputtering time to 10-120min to complete the sputtering of the metal nitride intermediate layer.

6. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: In S6, the following steps are specifically included: turning off the nitrogen and argon gases, turning off the sputtering system and the heating system, waiting for the temperature to drop below 120°C, turning on the multi-arc ion plating system, and evacuating to 3×10 -4 Pa, start multi-arc ion plating, the carbon target arc current is 50-150A, the metal target arc current is 50-150A, the turntable bias is 100-2000V, and the time is 5-60min.

7. The method for preparing a highly conductive and corrosion-resistant composite coating according to claim 1, wherein: S5 further includes repeatedly depositing two metals and nitrides of the two metals to form an n-layer intermediate layer; wherein n is less than or equal to 50.

8. The method for preparing a highly conductive, corrosion-resistant composite coating according to any one of claims 1 to 7, wherein: In S4, pure metal is deposited to form a metal base layer, the thickness of the metal base layer is 0.01-0.3 μm, and metal nitride is deposited to form a metal nitride base layer, the thickness of the metal nitride base layer is 0.01-0.3 μm; in S5, two metals are deposited to form a metal intermediate layer, the thickness of the metal intermediate layer is 0.01-0.5 μm; two metal nitrides are deposited to form a metal nitride intermediate layer, the thickness of the metal nitride intermediate layer is 0.01-1 μm.

9. A highly conductive, corrosion-resistant composite coating, characterized by: The high-conductivity, corrosion-resistant composite coating is prepared by the preparation method according to any one of claims 1 to 8.

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