A process for the production of a metal surface coating

Abstract

The present application relates to a kind of preparation processes of metal surface coating, comprising the following steps: step one, the surface of metal substrate is ground;Step two, the metal substrate after grinding is sequentially cleaned and dried;Step three, the surface of metal substrate after drying is coated, the coating process is first used multiple arc ion plating to form diffusion layer structure on the surface of metal substrate, then using magnetron sputtering process to deposit the composite film layer of metal layer and non-metal layer on the surface of diffusion layer.The present application uses multiple arc ion plating combined with magnetron sputtering method, uses ion bombardment to form a diffusion layer structure on the surface of metal substrate, the structure is dense, can prevent corrosion ions from entering, improve corrosion resistance, then using magnetron sputtering to deposit the multilayer composite film layer of metal layer and non-metal layer on the surface of diffusion layer, using non-metal layer to block the columnar crystal structure of metal layer, so that corrosion ions are not easy to enter the inside of coating, enhance the bonding force and corrosion resistance.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology, and more specifically to a process for preparing a metal surface coating. Background Technology

[0002] Traditional chemical electroplating generates significant wastewater discharge, while paint spraying produces certain amounts of exhaust gas emissions; both are undergoing rectification and technological innovation. Vacuum electroplating, with its superior decorative effects and zero emissions of wastewater, waste gas, and solid waste, has gained popularity among manufacturers and consumers, becoming one of the mainstream methods to replace traditional chemical electroplating coatings.

[0003] For example, the Chinese invention patent application CN202210129870.3 (publication number CN114457309A) discloses a method for easy-clean surface treatment of hardware, which specifically includes the following steps: installing a multi-arc ion plating target, which can be one or more of chromium, zirconium, and titanium; loading a cleaned and dried electroplating sample, evacuating to a background vacuum, and then performing ion plating; keeping the sample clean, transferring the PVD-coated sample to a spraying fixture and then spraying a nano easy-clean material; and baking and drying the sample after spraying the nano easy-clean material at a temperature of 60–140°C for 20–60 minutes.

[0004] This patent involves depositing a metal film with a certain roughness on the surface of chromium-plated hardware products, and then spraying a layer of nano-easy-clean material onto the surface of the film. This results in a product surface with strong scratch resistance, easy cleaning, and long service life without changing the color and texture of the metal.

[0005] However, the hardware products covered by this patent are limited to electroplated chrome products, which has a narrow range of applications. In addition, this patent improves the scratch resistance of hardware products by increasing the hardness of the coating, but it does not improve the corrosion resistance of the products. Only products that are aesthetically pleasing, healthy, wear-resistant, corrosion-resistant, and easy to clean would better meet consumer needs. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a preparation process for a metal surface coating with good corrosion resistance, in light of the current state of the prior art.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a preparation process for a metal surface coating, characterized by comprising the following steps:

[0008] Step 1: Grind the surface of the metal substrate;

[0009] Step 2: Clean and dry the ground metal substrate in sequence;

[0010] Step 3: Deposit a film on the dried metal substrate surface. The coating process first uses multi-arc ion plating to form a diffusion-like layer structure on the surface of the metal substrate, and then uses magnetron sputtering to deposit a composite film of metal and non-metal layers on the diffusion-like layer surface.

[0011] Preferably, in step three, the multi-arc ion plating process includes the following steps:

[0012] (1) Place the dried metal substrate into a vacuum furnace. The coating temperature is 50℃-150℃, and the background vacuum is 0.006-0.008Pa. After the background vacuum is reached, argon gas is introduced to perform glow discharge cleaning on the metal substrate. The bias power supply voltage is controlled at 600-800V, the bias duty cycle is 40%-60%, the vacuum degree is 0.6-1Pa, and the time is 10-20min.

[0013] (2) Then the metal substrate is bombarded with ions. The bias power supply voltage is controlled at 250-500V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum is 0.08-0.12Pa, the time is 2-15min, the multi-arc current is 70-90A, and the multi-arc target material is one or more of titanium, zirconium, chromium and nickel, forming a diffusion-like layer structure on the surface of the metal substrate.

[0014] Preferably, in step three, the composite film preparation process is as follows:

[0015] (a) The bias power supply voltage is controlled at 50-200V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum is 0.3-0.5Pa, the time is 5-20min, the medium frequency current is 10-30A, and the bottom layer film is deposited on the surface of the diffusion-like layer.

[0016] (b) Then the bias power supply voltage is controlled at 50-200V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum degree is 0.3-0.5Pa, the time is 5-30min, the medium frequency current is 10-30A, and the target material is two or more of chromium, titanium, aluminum and silicon. The target materials are alternately formed and deposited on the bottom film layer to form the multilayer composite film layer.

[0017] To improve the aesthetics of the coating, the preparation process further includes step four: depositing a color layer on the surface of the composite film layer, wherein the preparation process of the color layer is as follows:

[0018] The bias power supply voltage is controlled at 50-100V, the bias duty cycle is 40%-60%, the working gas is argon, the reaction gas is one or more of nitrogen, acetylene, and oxygen, the vacuum is 0.3-0.5Pa, the time is 20-60min, and the medium frequency current is 10-30A.

[0019] To make the coating easy to clean, the preparation process also includes step five, which involves spraying an easy-clean coating onto the surface of the color layer.

[0020] Preferably, the easy-clean coating is hydrophobic and oleophobic to facilitate cleaning.

[0021] Preferably, in step one, the grinding process is magnetic grinding. Compared to traditional grinding methods, magnetic grinding is more efficient at removing burrs and achieving a smooth surface on metal substrates.

[0022] Preferably, the magnetic abrasive uses 304 stainless steel needles with a diameter of 0.2-1.2 mm and a length of 5-15 cm. The magnetic abrasive power is set to 50-60 Hz and the time is set to 4-20 min. The magnetic abrasive disk switches between forward and reverse rotation every set time interval.

[0023] Preferably, in step two, the metal substrate is sequentially subjected to at least one tap water wash, ultrasonic degreasing, at least one pure water wash, ultrasonic pure water wash, and ultrapure hot water wash to ensure that the surface of the substrate is clean enough, free of watermarks and stains, and to guarantee the adhesion performance between the substrate and the PVD coating layer.

[0024] Preferably, the conductivity of the ultrapure water used for hot water washing is controlled at 0.1–1.0 μS / cm³, and the temperature is controlled at 40–50 °C.

[0025] Compared with the prior art, the advantages of the present invention are as follows: 1. The present invention adopts a multi-arc ion plating combined with magnetron sputtering method to form a diffusion-like layer structure on the surface of a metal substrate by ion bombardment. This structure is dense and can prevent corrosion ions from entering, thereby improving corrosion resistance. Then, a multi-layer composite film of metal and non-metal layers is deposited on the surface of the diffusion-like layer by magnetron sputtering. The non-metal layer is used to block the columnar crystal structure of the metal layer, thereby making it difficult for corrosion ions to enter the coating interior, enhancing the adhesion and corrosion resistance; 2. The coating of the present invention can be directly applied to the metal substrate without prior electroplating treatment of the metal substrate, and the process is simple. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments.

[0027] Example 1

[0028] This invention provides a process for preparing a metal surface coating, the process comprising the following steps:

[0029] Step 1: Perform magnetic grinding on the metal substrate: Select stainless steel as the metal substrate, place the stainless steel part into the magnetic grinding tank, add a small amount of grinding fluid to the tank, set the power to 60HZ, set the time to 12min, and switch the disk forward and reverse every 2min to start grinding.

[0030] Step 2: Clean and dry the stainless steel parts after magnetic grinding.

[0031] The cleaning process is as follows: The magnetically ground stainless steel parts are hung on the cleaning line and sequentially undergo two tap water washes, ultrasonic degreasing, two pure water washes, an ultrasonic pure water wash, and an ultrapure water hot water wash. Each process takes 5 minutes. The ultrapure water hot water wash requires controlling the conductivity to below 1 μS / cm³ and the water temperature to 45±5℃. Finally, the parts are dried at 120℃. The resulting stainless steel parts have a clean surface free of water stains.

[0032] Step 3: Vacuum coating is performed on the dried stainless steel parts;

[0033] (1) Transfer the dried stainless steel parts into a vacuum furnace and heat them to 150°C. Evacuate the vacuum furnace to 0.007Pa, then introduce argon gas and turn on the bias power supply to perform glow discharge cleaning on the surface of the workpiece. The process parameters used are: bias voltage of 700V, duty cycle of 50%, time of 15min, and vacuum degree of 0.8Pa.

[0034] (2) Argon gas is introduced and the stainless steel parts are bombarded with ions when the vacuum reaches 0.1 Pa. The target material is a multi-arc chromium target. The process parameters are: bias voltage of 250V, duty cycle of 50%, multi-arc current of 75A, and time of 2min, thereby forming a diffusion-like layer on the surface of the stainless steel parts.

[0035] (3) The bottom layer is formed by depositing a bottom layer on the surface of the diffusion layer: the bias power supply voltage is controlled at 100V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.4Pa, the time is 5min, and the medium frequency current is 25A.

[0036] (4) Apply a transition layer coating to stainless steel parts: the bias power supply voltage is controlled at 80V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.4Pa, the time is 10min, the medium frequency current is 25A, the target material is chromium target and silicon target, the target material is alternately deposited on the bottom layer to form a multilayer composite film.

[0037] Step 4: Apply a color coating to the stainless steel parts: The bias power supply voltage is controlled at 80V, the bias duty cycle is 50%, the working gas is argon, the reaction gas is acetylene, the vacuum is 0.4Pa, the time is 40min, and the medium frequency current is 25A, so that the color layer is deposited on the composite film.

[0038] Step 5: Apply a 5µm thick layer of wear-resistant nano easy-clean coating to the stainless steel parts after the above-mentioned corrosion-resistant PVD coating is applied. Then, dry the coated stainless steel parts at high temperature, with a baking curing temperature of 180℃ and a time of 30 minutes.

[0039] Example 2

[0040] This invention provides a process for preparing a metal surface coating, the process comprising the following steps:

[0041] Step 1: Perform magnetic polishing on the metal substrate: Select a copper alloy part as the metal substrate, place the copper alloy part into the magnetic polishing tank, add a small amount of polishing fluid to the tank, set the power to 60HZ, set the time to 12min, and switch the disk forward and reverse every 2min to start polishing.

[0042] Step 2: Clean and dry the copper alloy parts after magnetic polishing;

[0043] The cleaning process is as follows: The magnetically ground workpiece is hung on the cleaning line and sequentially undergoes two tap water washes, ultrasonic degreasing, two pure water washes, an ultrasonic pure water wash, and an ultrapure water hot water wash. Each process takes 5 minutes in the tank. The ultrapure water hot water wash requires controlling the conductivity to be below 1μS / cm3 and the water temperature to be controlled at 45±5℃. Then, it is dried at 120℃. The copper alloy part comes out clean and free of water stains.

[0044] Step 3: Vacuum plating is performed on the cleaned copper alloy parts;

[0045] (1) The cleaned copper alloy parts are transferred into a vacuum furnace and heated to 120°C. The vacuum furnace is evacuated to 0.008Pa, and then argon gas is introduced. The bias power supply is turned on to perform glow discharge cleaning on the surface of the copper alloy parts. The process parameters used are: bias voltage of 800V, duty cycle of 60%, time of 20min, and vacuum degree of 1Pa.

[0046] (2) Argon gas is introduced and the workpiece is bombarded with ions at a vacuum of 0.12 Pa. The target material is a multi-arc chromium target. The process parameters are: bias voltage of 500V, duty cycle of 60%, multi-arc current of 90A, and time of 15min to form a diffusion-like layer on the surface of the copper alloy part.

[0047] (3) The bottom layer is formed by depositing a bottom layer on the surface of the diffusion layer: the bias power supply voltage is controlled at 50V, the bias duty cycle is 60%, the working gas is argon, the vacuum is 0.5Pa, the time is 15min, and the medium frequency current is 30A.

[0048] (4) Apply a transition layer coating to the copper alloy parts: the bias power supply voltage is controlled at 50V, the bias duty cycle is 60%, the working gas is argon, the vacuum is 0.5Pa, the time is 15min, the medium frequency current is 30A, the target material is chromium target and silicon target, and the target material is alternately deposited on the bottom layer to form a multilayer composite film.

[0049] Step 4: Apply a color layer coating to the copper alloy parts: The bias power supply voltage is controlled at 50V, the bias duty cycle is 60%, the working gas is argon, the reaction gas is acetylene, the vacuum is 0.5Pa, the time is 60min, and the medium frequency current is 30A, so that the color layer is deposited on the composite film layer.

[0050] Step 5: Apply a wear-resistant nano easy-clean coating to the copper alloy parts after the above corrosion-resistant PVD coating is applied. The coating thickness is 5 μm. Dry the coated copper alloy parts at high temperature. The baking curing temperature is 180℃ and the time is 30 min.

[0051] Example 3

[0052] This invention provides a process for preparing a metal surface coating, the process comprising the following steps:

[0053] Step 1: Perform magnetic grinding on the metal substrate: Select a zinc alloy part as the metal substrate, place the zinc alloy part into the magnetic grinding tank, add a small amount of grinding fluid to the tank, set the power to 60HZ, set the time to 12min, and switch the disk forward and reverse every 2min to start grinding.

[0054] Step 2: Clean and dry the zinc alloy parts after magnetic grinding;

[0055] The cleaning process is as follows: The magnetically ground zinc alloy parts are hung on the cleaning line and sequentially undergo two tap water washes, ultrasonic degreasing, two pure water washes, an ultrasonic pure water wash, and an ultrapure hot water wash. Each process takes 5 minutes in the tank. The pure hot water wash requires controlling the conductivity to below 1 μS / cm³ and the water temperature to 45±5℃. Finally, the parts are dried at 120℃. The resulting zinc alloy parts have a clean surface free of water stains.

[0056] Step 3: Vacuum coating is performed on the cleaned zinc alloy parts;

[0057] (1) Transfer the cleaned zinc alloy parts into a vacuum furnace and heat it to 80°C. Evacuate the vacuum furnace to 0.007Pa, then introduce argon gas and turn on the bias power supply to perform glow discharge cleaning on the surface of the zinc alloy parts. The process parameters used are: bias voltage of 600V, duty cycle of 50%, time of 10min, and vacuum degree of 0.8Pa.

[0058] (2) Argon gas is introduced and the zinc alloy part is bombarded with ions when the vacuum degree reaches 0.08 Pa. The target material is a multi-arc chromium target. The process parameters are: bias voltage of 350V, duty cycle of 50%, multi-arc current of 70A, and time of 2min, forming a diffusion-like layer on the surface of the zinc alloy part.

[0059] (3) The bottom layer is formed by depositing a bottom layer on the surface of the diffusion layer: the bias power supply voltage is controlled at 200V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.3Pa, the time is 20min, and the medium frequency current is 10A.

[0060] (4) Apply a transition layer coating to the zinc alloy parts: the bias power supply voltage is controlled at 200V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.3Pa, the time is 30min, the medium frequency current is 10A, the target material is chromium target and silicon target, and the target material is deposited alternately on the bottom film layer to form a multilayer composite film layer.

[0061] Step 4: Apply a color coating to the zinc alloy parts. The bias power supply voltage is controlled at 200V, the bias duty cycle is 50%, the working gas is argon, the reaction gas is acetylene, the vacuum is 0.3Pa, the time is 20min, and the medium frequency current is 10A, thereby depositing the color layer on the composite film.

[0062] Step 5: Apply a wear-resistant nano easy-clean coating to the zinc alloy parts after the above-mentioned corrosion-resistant PVD coating is applied. The coating thickness is 5 μm. Dry the coated zinc alloy parts at high temperature. The baking curing temperature is 180℃ and the time is 30 min.

[0063] Example 4

[0064] This invention provides a process for preparing a metal surface coating, the process comprising the following steps:

[0065] Step 1: Perform magnetic polishing on the metal substrate: Select a magnesium alloy part as the metal substrate, place the magnesium alloy part into the magnetic polishing tank, add a small amount of polishing fluid to the tank, set the power to 60HZ, set the time to 12min, and switch the disk forward and reverse every 2min to start polishing.

[0066] Step 2: Clean and dry the magnesium alloy parts after magnetic grinding;

[0067] The cleaning process is as follows: The magnetically ground workpiece is hung on the cleaning line and sequentially undergoes two tap water washes, ultrasonic degreasing, two pure water washes, an ultrasonic pure water wash, and an ultrapure hot water wash. Each process takes 5 minutes in the tank. The pure hot water wash requires controlling the conductivity to be below 1μS / cm3 and the water temperature to be controlled at 45±5℃. After drying at 120℃, the surface of the workpiece is clean and free of water stains.

[0068] Step 3: Vacuum coating is performed on the cleaned magnesium alloy parts;

[0069] (1) The cleaned magnesium alloy parts are transferred into a vacuum furnace and heated to 50°C. The vacuum furnace is evacuated to 0.006Pa, and then argon is introduced. The bias power supply is turned on to perform glow discharge cleaning on the surface of the workpiece. The process parameters used are: bias voltage of 700V, duty cycle of 40%, time of 10min, and vacuum degree of 0.6Pa.

[0070] (2) Argon gas is introduced and the workpiece is bombarded with ions when the vacuum reaches 0.08 Pa. The target material is a multi-arc chromium target. The process parameters are: bias voltage of 400V, duty cycle of 50%, multi-arc current of 80A, and time of 2min, forming a diffusion-like layer on the surface of the magnesium alloy part.

[0071] (3) The bottom layer is formed by depositing a bottom layer on the surface of the diffusion layer: the bias power supply voltage is controlled at 150V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.4Pa, the time is 10min, and the medium frequency current is 15A.

[0072] (4) Apply a transition layer coating to magnesium alloy parts: the bias power supply voltage is controlled at 150V, the bias duty cycle is 50%, the working gas is argon, the vacuum is 0.4Pa, the time is 30min, the medium frequency current is 15A, the target material is chromium target and silicon target, the target material is alternately deposited on the bottom layer to form a multilayer composite film.

[0073] Step 4: Apply a color layer coating to the magnesium alloy parts. The bias power supply voltage is controlled at 150V, the bias duty cycle is 50%, the working gas is argon, the reaction gas is acetylene, the vacuum is 0.4Pa, the time is 40min, and the medium frequency current is 15A, thereby depositing the color layer on the composite film.

[0074] Step 5: Apply a wear-resistant nano easy-clean coating to the magnesium alloy parts after the corrosion-resistant PVD coating has been applied. The coating thickness is 5 μm. Dry the coated magnesium alloy parts at high temperature. The baking curing temperature is 180℃ and the time is 30 min.

[0075] In step one of the above embodiments, the magnetic grinding tank and grinding fluid can both adopt existing technology. Grinding is carried out using 304 stainless steel needles with a diameter of 0.2 to 1.2 mm and a length of 5 to 15 cm. The nano easy-clean coating is hydrophobic and oleophobic and is FW 2 purchased from Shanghai Tongyao New Material Technology Co., Ltd.

[0076] The following tests were performed on the product of this embodiment in accordance with the following standards:

[0077] 1. AASS (Anti-corrosion test MGFC-ES119);

[0078] 2. NSS (Salt Spray Test MGFC-ES135);

[0079] 3. Abrasion resistance test (MGFC-outsource-Moen abrasion);

[0080] 4. Water immersion test (MGFC-ES135);

[0081] 5. Chemical resistance test (MGFC-ES135 & GB);

[0082] 6. Pencil hardness (MGFC-GB>9H);

[0083] 7. Dyne-Ratio Test (MGFC-ES221);

[0084] 9. Aging Test (NOLM-ES152)

[0085] The test results for each of the above embodiments are as follows:

[0086] 1. AASS 24h OK;

[0087] 2. NSS 96h OK;

[0088] 3. Abrasion resistance test OK;

[0089] 4. Water immersion test OK;

[0090] 5. Chemical resistance test OK;

[0091] 6. Pencil hardness > 9H;

[0092] 7. Dyne ratio test OK;

[0093] 8. Aging test OK.

[0094] That is, the coatings in each embodiment can meet the test requirements.

[0095] The film prepared by the process of the present invention has not only scratch resistance but also good corrosion resistance, and also has hydrophobic, oleophobic and easy-to-clean properties.

Claims

1. A process for preparing a metal surface coating, characterized in that, Includes the following steps: Step 1: Grind the surface of the metal substrate; Step 2: Clean and dry the ground metal substrate in sequence; Step 3: Coating the surface of the dried metal substrate. The coating process first uses multi-arc ion plating to form a diffusion-like layer structure on the surface of the metal substrate. This diffusion-like layer structure is dense and can prevent corrosion ions from entering, thus improving corrosion resistance. Then, a composite film of metal and non-metal layers is deposited on the surface of the diffusion-like layer using magnetron sputtering. The non-metal layer is used to block the columnar crystal structure of the metal layer, thereby making it difficult for corrosion ions to enter the coating and enhancing the adhesion and corrosion resistance. In step three, the multi-arc ion plating process includes the following steps: (1) Place the dried metal substrate into a vacuum furnace. The coating temperature is 50℃-150℃ and the background vacuum is 0.006-0.008Pa. After the background vacuum is reached, argon gas is introduced to perform glow discharge cleaning on the metal substrate. The bias power supply voltage is controlled at 600-800V, the bias duty cycle is 40%-60%, the vacuum degree is 0.6-1Pa, and the time is 10-20 min. (2) Then the metal substrate is bombarded with ions. The bias power supply voltage is controlled at 250-500V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum is 0.08-0.12Pa, the time is 2-15min, the multi-arc current is 70-90A, and the multi-arc target material is one or more of titanium, zirconium, chromium and nickel, forming a diffusion-like layer structure on the surface of the metal substrate. In step three, the composite film preparation process is as follows: (a) The bias power supply voltage is controlled at 50-200V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum is 0.3-0.5Pa, the time is 5-20min, the medium frequency current is 10-30A, and the bottom layer film is deposited on the surface of the diffusion-like layer. (b) Then the bias power supply voltage is controlled at 50-200V, the bias duty cycle is 40%-60%, the working gas is argon, the vacuum degree is 0.3-0.5Pa, the time is 5-30min, the medium frequency current is 10-30A, and the target material is two or more of chromium, titanium, aluminum and silicon. The target materials are alternately formed and deposited on the bottom film layer to form the composite film layer.

2. The preparation process of the metal surface coating according to claim 1, characterized in that: The process also includes step four: a color layer is deposited on the surface of the composite film layer, and the preparation process of the color layer is as follows: The bias power supply voltage is controlled at 50-100V, the bias duty cycle is 40%-60%, the working gas is argon, the reaction gas is one or more of nitrogen, acetylene, and oxygen, the vacuum is 0.3-0.5Pa, the time is 20-60min, and the medium frequency current is 10-30A.

3. The preparation process of the metal surface coating according to claim 2, characterized in that: It also includes step five, which involves spraying an easy-clean coating onto the surface of the color layer.

4. The preparation process of the metal surface coating according to claim 3, characterized in that: The easy-clean coating is hydrophobic and oleophobic.

5. The preparation process of the metal surface coating according to claim 1, characterized in that: In step one, the grinding process is magnetic grinding.

6. The preparation process of the metal surface coating according to claim 5, characterized in that: The magnetic polishing power is set to 50~60HZ, the time is set to 4~20min, and the magnetic polishing disk switches between forward and reverse rotation every set time.

7. The preparation process of the metal surface coating according to claim 1, characterized in that: In step two, the metal substrate undergoes at least one tap water wash, ultrasonic degreasing, at least one pure water wash, ultrasonic pure water wash, and ultrapure hot water wash in sequence.

8. The preparation process of the metal surface coating according to claim 7, characterized in that: The conductivity of the ultrapure water used for hot water washing is controlled at 0.1~1.0μS / cm3, and the temperature is controlled at 40~50℃.