Surface treatment method of stainless steel water tank and stainless steel water tank

Abstract

The invention provides a surface treatment method of a stainless steel water tank and the stainless steel water tank. The stainless steel water tank comprises a base material layer, and a sand blasting layer, a composite chromium carbide coating, a corrosion-resistant layer and a wear-resistant layer are sequentially arranged on the surface of the base material layer; the composite chromium carbide coating at least comprises four layers. Through the varnish coating with a multi-layer structure, the wear resistance and the corrosion resistance of the stainless steel water tank are remarkably improved, and even if the varnish on the outer layer is damaged, the middle layer can still effectively protect the base material from being corroded, so that the service life of the water tank is prolonged; meanwhile, the bottom composite chromium carbide coating improves the wear resistance of the stainless steel water tank and enriches the appearance of the stainless steel water tank. Due to the design of the multi-layer coating structure, the functions of all the layers are complementary, and the overall performance of the water tank is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of kitchen sink manufacturing, relates to a stainless steel kitchen sink and its preparation, and in particular to a surface treatment method of a stainless steel sink with multi-layer varnish and composite chromium carbide coating and a stainless steel sink. Background Art

[0002] Sinks are a common appliance in the kitchen and bathroom fields, most of which are stainless steel sinks (e.g., sinks in the kitchen).

[0003] Stainless steel has high strength, hardness, wear resistance and good corrosion resistance. However, because the stainless steel decorative plate is a high-gloss mirror, if the surface film is soft, it is easy to be scratched and deformed, affecting the appearance and thus the overall aesthetics of the kitchen. Generally, the friction coefficient of the metal surface is high and the surface is not smooth enough. In order to improve the surface hardness and scratch resistance of stainless steel, surface treatment is required on this metal stainless steel substrate.

[0004] Stainless steel sinks on the market currently usually use single-layer PVD coating technology to enhance the hardness and corrosion resistance of the surface. However, although the PVD coating has a certain hardness and corrosion resistance, in actual use, especially when it is rubbed and hit by metal utensils, the coating is still easily scratched, resulting in the substrate being exposed and further corroded. In addition, the existing varnish coating is usually a single-layer structure, which is difficult to meet the dual requirements of high wear resistance and high corrosion resistance at the same time, which limits the service life of the sink.

[0005] For example, patent publication number CN103074924A, an invention patent named an anti-fingerprint stainless steel sink and its production method, discloses that the surface of a stainless steel sink body is coated with a surface paint layer. The production method of the anti-fingerprint stainless steel sink is: firstly, the stainless steel sink body is ultrasonically cleaned; then, the cleaned stainless steel sink body is subjected to dust removal treatment by an electrostatic dust removal gun; finally, surface paint is sprayed on the surface of the stainless steel sink body after dust removal and dried. The anti-fingerprint stainless steel sink made by this technology has stronger corrosion resistance, but it cannot solve the problem that its wear resistance is poor and the coating is still easily scratched when rubbed and impacted by metal utensils. Summary of the invention

[0006] In order to solve the problem that a single-layer PVD coating of a stainless steel water sink is still easily scratched when subjected to friction and impact by metal utensils, and a single varnish coating cannot have both high wear resistance and high corrosion resistance, resulting in a low service life, the present invention provides a surface treatment method for a stainless steel water sink.

[0007] Another object of the present invention is to provide a stainless steel sink obtained by the above surface treatment method.

[0008] The present invention significantly improves the wear resistance and corrosion resistance of the stainless steel water tank through the multi-layer varnish coating. Even if the outer varnish is damaged, the middle layer can still effectively protect the substrate from corrosion, thereby extending the service life of the water tank; at the same time, the bottom PVD layer improves the wear resistance of the stainless steel water tank and enriches the appearance of the stainless steel water tank. The design of the multi-layer coating structure makes the functions of each layer complementary, and the overall performance of the water tank is greatly improved.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] The present invention first provides a surface treatment method for a stainless steel water tank, the surface treatment method comprising the following steps:

[0011] preparing a composite chromium carbide coating on the surface of the substrate layer;

[0012] Spraying a corrosion-resistant layer on the surface of the composite chromium carbide coating;

[0013] The wear-resistant layer is sprayed on the surface of the corrosion-resistant layer, and the layer is dried and solidified to obtain the stainless steel water tank with the multi-layer varnish and composite chromium carbide coating.

[0014] In the present invention, the single chromium layer in the composite chromium carbide coating is used as a primer coating to make the coating and the substrate more tightly and firmly bonded; the chromium nitride coating increases the corrosion resistance of the composite chromium carbide coating; the chromium carbonitride coating serves as a transition coating between the chromium nitride and chromium carbide coatings, thereby increasing the bonding strength of the two coatings and serving as an intermediate transition coating to make the coating denser and more delicate; finally, the chromium carbide is used as a coloring coating to give the overall coating a gun-gray appearance.

[0015] The bottom fluororesin varnish material outside the composite chromium carbide coating, as a corrosion-resistant layer, has strong corrosion resistance and strong sealing, effectively blocking the contact between corrosive liquid and PVD coating and substrate, protecting the composite chromium carbide coating and stainless steel substrate from corrosion. The outer silicone resin varnish material, as a scratch-resistant and heat-resistant varnish coating, has a high temperature resistance of 250 degrees and a hardness of 9H, effectively protecting the inner fluororesin varnish from scratches and high temperature damage.

[0016] As a preferred embodiment of the present invention, before preparing the composite chromium carbide coating on the surface of the substrate layer, the method further comprises:

[0017] The surface of the substrate layer is sandblasted, ultrasonically degreased, de-glued, cleaned and dried for later use;

[0018] The treated substrate layer was transferred into a vacuum furnace, evacuated to 1.0E-2Pa and heated to 200°C; the throttle valve of the vacuum furnace was closed, argon gas was introduced, 800V high bias was turned on, and the duty cycle was maintained at 50%; ion glow cleaning was performed for 500s.

[0019] As a preferred embodiment of the present invention, the step of preparing the composite chromium carbide coating on the surface of the substrate layer comprises:

[0020] Fill the vacuum furnace with argon gas, turn on the bias voltage of 500V, turn on the chromium target, the chromium target current is 90A, deposit the single chromium layer, and the deposition time is 500s;

[0021] Fill the vacuum furnace with nitrogen, turn on the 200V bias, turn on the chromium target, the chromium target current is 90A, and deposit the chromium nitride layer for 500s;

[0022] A mixed gas of acetylene and nitrogen was filled into the vacuum furnace, a bias voltage of 180 V was turned on, a chromium target was turned on, a chromium target current was 90 A, and a chromium carbonitride layer was deposited for 500 s.

[0023] Fill acetylene into the vacuum furnace, turn on the 150V bias, turn on the chromium target, the chromium target current is 90A, deposit the chromium carbide layer, and the deposition time is 1500s;

[0024] After the deposition is completed, the vacuum furnace is cooled to below 100° C. and then taken out to obtain a substrate having a composite chromium carbide coating.

[0025] In the present invention, a wet-to-wet spraying process is adopted between the fluororesin varnish (i.e., the corrosion-resistant layer) and the silicone resin varnish (i.e., the wear-resistant layer), thereby avoiding the problem that the bottom layer of fluororesin varnish (i.e., the corrosion-resistant layer) becomes non-sticky after high-temperature curing, making it impossible to spray the second layer of silicone resin varnish (i.e., the wear-resistant layer).

[0026] As a preferred embodiment of the present invention, the flow rate of argon is 675-725sccm; the flow rate of nitrogen is 825-875sccm; in the mixed gas of acetylene and nitrogen, the flow rate of acetylene is 425-475sccm, and the flow rate of nitrogen is 275-325sccm; the flow rate of acetylene is 1075-1125sccm.

[0027] As a preferred solution of the present invention, spraying the corrosion-resistant layer on the surface of the composite chromium carbide coating is to uniformly coat the corrosion-resistant fluororesin varnish material on the surface of the composite chromium carbide coating by electrostatic spraying.

[0028] As a preferred solution of the present invention, spraying the wear-resistant layer on the surface of the corrosion-resistant layer is to uniformly coat the wear-resistant silicone resin varnish material on the surface of the corrosion-resistant layer by electrostatic spraying.

[0029] The present invention also provides a stainless steel water tank having multiple varnish layers and a composite chromium carbide coating obtained by the above-mentioned surface treatment method, comprising a substrate layer, wherein a sandblasting layer, a composite chromium carbide coating, a corrosion-resistant layer and a wear-resistant layer are sequentially arranged on the surface of the substrate layer; the composite chromium carbide coating comprises at least 4 layers.

[0030] As a preferred solution of the present invention, the composite chromium carbide coating is sequentially composed of a single chromium layer, a chromium nitride layer, a chromium carbonitride layer and a chromium carbide layer, and the thickness of each layer is 0.3 μm-0.8 μm.

[0031] As a preferred solution of the present invention, the corrosion-resistant layer is a corrosion-resistant fluororesin varnish layer with a thickness of 1 μm-2 μm; the wear-resistant layer is a wear-resistant silicone resin varnish layer with a thickness of 1 μm-2 μm.

[0032] The present invention also provides another surface treatment method for a stainless steel water tank, the treatment method comprising: embossing the bottom substrate surface of the stainless steel water tank, electroplating a layer of hard chrome on the embossed substrate surface, and depositing a PVD coating on the stainless steel water tank with the hard chrome-plated embossed substrate.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The present invention uses a composite chromium carbide coating and uses a single chromium layer as a primer coating to improve the bonding force between the coating and the substrate, so that the coating and the substrate are more tightly and firmly bonded; the chromium nitride layer is used to increase the corrosion resistance of the composite chromium carbide coating; the chromium carbonitride layer is used as a transition coating to increase the bonding force between the single chromium layer and the chromium nitride layer, and at the same time as an intermediate transition layer, making the coating denser and more delicate; the chromium carbide layer is used as a coloring coating to give the overall coating a gun-gray appearance.

[0035] 2) The present invention adopts fluororesin varnish material as the corrosion-resistant layer, which itself has strong corrosion resistance and strong sealing performance, effectively blocking the contact between corrosive liquid and the composite chromium carbide coating and the stainless steel substrate, protecting the composite chromium carbide coating and the stainless steel substrate from corrosion; the outer layer adopts silicone resin varnish material as the scratch and heat-resistant varnish coating, which has a high temperature resistance of 250°C and a hardness of up to 9H, effectively protecting the corrosion-resistant layer from scratches and high temperature damage.

[0036] 3) The present invention significantly improves the wear resistance and corrosion resistance of the stainless steel water sink through the multi-layer varnish coating. Even if the outer layer of varnish is damaged, the middle layer can still effectively protect the substrate from corrosion, thereby extending the service life of the water sink; at the same time, the bottom PVD layer improves the wear resistance of the stainless steel water sink and enriches the appearance of the stainless steel water sink. The design of the multi-layer coating structure makes the functions of each layer complementary, and the overall performance of the water sink is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 It is a schematic diagram of the present invention.

[0039] In the figure, 1. substrate layer; 2. sandblasting layer; 3. composite chromium carbide coating; 3-1. single chromium layer; 3-2. chromium nitride layer; 3-3. chromium carbonitride layer; 3-4. chromium carbide layer; 4. corrosion-resistant layer; 5. wear-resistant layer. DETAILED DESCRIPTION

[0040] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in 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 work are within the scope of protection of the present invention.

[0041] See also Figure 1 The stainless steel water tank with multi-layer varnish and composite chromium carbide coating provided by the present invention comprises a substrate layer 1, on the surface of which a sandblasting layer 2, a composite chromium carbide coating 3, a corrosion-resistant layer 4 and a wear-resistant layer 5 are sequentially arranged; the composite chromium carbide coating 3 is sequentially composed of a single chromium layer 3-1, a chromium nitride layer 3-2, a chromium carbonitride layer 3-3 and a chromium carbide layer 3-4, and each layer has a thickness of 0.5 μm.

[0042] The corrosion-resistant layer 4 is a corrosion-resistant fluororesin varnish layer with a thickness of 1 μm-2 μm.

[0043] The wear-resistant layer 5 is wear-resistant silicone resin varnish with a thickness of 1 μm-2 μm.

[0044] The present invention uses different materials for each layer to achieve different functions through the selection of materials.

[0045] In the present invention, the single chromium layer in the composite chromium carbide coating is used as a primer coating to make the coating and the substrate more tightly and firmly bonded; the chromium nitride coating increases the corrosion resistance of the composite chromium carbide coating; the chromium carbonitride coating serves as a transition coating between the chromium nitride and chromium carbide coatings, thereby increasing the bonding strength of the two coatings and serving as an intermediate transition coating to make the coating denser and more delicate; finally, the chromium carbide is used as a coloring coating to give the overall coating a gun-gray appearance.

[0046] The bottom fluororesin varnish material outside the composite chromium carbide coating, as a corrosion-resistant layer, has strong corrosion resistance and strong sealing, effectively blocking the corrosive liquid from contacting the PVD coating and the stainless steel substrate, protecting the composite chromium carbide coating and the stainless steel substrate from corrosion. The outer silicone resin varnish material, as a scratch-resistant and heat-resistant varnish coating, has a high temperature resistance of 250°C, and the hardness can reach 9H, effectively protecting the inner fluororesin varnish from scratches and high temperature damage.

[0047] The present invention uses interlayer bonding technology to ensure good bonding strength and stability between the layers.

[0048] In the composite chromium carbide coating, a single chromium layer is added as a primer coating before the anti-corrosion chromium nitride coating to increase the bonding strength between the stainless steel substrate and the overall composite chromium carbide coating; a chromium carbonitride layer is added as a transition layer between the chromium nitride and the coloring chromium carbide coating to make the bonding between the two closer.

[0049] A wet-to-wet spraying process is used between the fluororesin varnish (i.e., the corrosion-resistant layer) and the silicone resin varnish (i.e., the wear-resistant layer), thereby avoiding the problem that the bottom layer of fluororesin varnish (i.e., the corrosion-resistant layer) becomes non-sticky after high-temperature curing, making it impossible to spray the second layer of silicone resin varnish (i.e., the wear-resistant layer).

[0050] The surface treatment method of the present invention comprises the following steps:

[0051] 1) The PVD process is used on the surface of the stainless steel sink to plate elemental chromium, chromium nitride, chromium carbonitride layer and chromium carbide to obtain a high-hardness and wear-resistant composite chromium carbide coating;

[0052] S1. Sandblast the surface of the stainless steel sink, remove oil and glue with ultrasonic wave, clean and dry it for later use;

[0053] S2. The stainless steel water tank after step S1 is transferred into a vacuum furnace, evacuated and heated; the throttle valve of the vacuum furnace is closed, argon gas is introduced, 800V high bias is turned on, and the duty cycle is maintained at 50%; ion glow cleaning is performed for 500s;

[0054] S3. Fill the vacuum furnace with argon, nitrogen, acetylene and nitrogen mixed gas, and acetylene in turn; turn on the bias voltage in turn; turn on the chromium target and the chromium target current at the same time, and deposit the single chromium layer, chromium nitride layer, chromium carbonitride layer and chromium carbide layer in turn; after depositing the composite chromium carbide coating, wait for the vacuum furnace to drop below 100°C, open the vacuum furnace, and take out the water tank for use.

[0055] Step S1 performs sandblasting on the surface of the stainless steel water tank to ensure that the surface of the stainless steel water tank (ie, the substrate layer) forms a clean, uniform, grease-free rough surface to enhance the surface adsorption force.

[0056] In this step, the sand blasting process is as follows: the sand blasting parameters are as follows: the sand blasting pressure is 0.4-0.6 MPA; the sand blasting line speed is 0.8 m / min; and the surface roughness is Ra greater than 0.8 μm.

[0057] Ultrasonic oil removal: Ultrasonic power: 0.8-1.5A; Oil removal time: 100-140s; Oil removal concentration: PH: 9.5-10.5; Total alkali: 16-26pt.

[0058] Cleaning process: 1: water washing; 2: ultrasonic degreasing; 3: water washing; 4: ultrasonic degumming; 5: water washing; 6: pure water washing; 7: 150° high temperature drying.

[0059] Step S3 performs PVD coating treatment on the stainless steel water tank, and uses the single chromium layer as a primer coating to improve the bonding strength between the coating and the substrate, so that the coating and the substrate are more tightly and firmly bonded; the chromium nitride layer is used to increase the corrosion resistance of the composite chromium carbide coating; the chromium carbonitride layer is used as a transition coating to increase the bonding strength between the single chromium layer and the chromium nitride layer, and at the same time as an intermediate transition layer, making the coating denser and more delicate; the chromium carbide layer is used as a coloring coating to give the overall coating a gun gray appearance.

[0060] The method for preparing the chromium carbide coating comprises:

[0061] 1. Physical Vapor Deposition (PVD): Chromium carbide material is deposited on the substrate material to form a coating through physical methods such as evaporation or sputtering. The PVD method can produce high-quality coatings with good adhesion and uniformity.

[0062] 2. Chemical vapor deposition (CVD): At high temperature, a compound of carbon and chromium is converted into chromium carbide through chemical reaction and deposited on the substrate. The CVD method can precisely control the coating composition and structure.

[0063] 3. Sol-gel method: The chromium carbide precursor is prepared by the sol-gel process and then converted into a chromium carbide coating by heat treatment. This method can achieve a coating with a complex shape.

[0064] 4. Laser cladding: Use a high-energy laser beam to melt chromium carbide powder and deposit it on the base material to form a coating. This method can achieve rapid preparation and local coating.

[0065] 5. Thermal spraying: The chromium carbide powder is heated to the melting point and then sprayed onto the base material to form a coating. This method is suitable for coating large parts.

[0066] 6. Electrochemical deposition: Chromium carbide is deposited on the surface of the substrate material through electrochemical reaction. This method is suitable for substrates with complex shapes.

[0067] The invention adopts physical vapor deposition (PVD) to prepare a composite chromium carbide coating on the surface of a substrate layer of a stainless steel water tank.

[0068] 2) Spraying a corrosion-resistant layer on the surface of the composite chromium carbide coating in step 1): Using electrostatic spraying technology, evenly apply a corrosion-resistant fluororesin varnish material as a corrosion-resistant layer with a thickness controlled between 1 and 2 microns to ensure even coverage of the composite chromium carbide coating, which can effectively prevent corrosion of the substrate.

[0069] Step 2) using fluororesin varnish material as the corrosion-resistant layer, fluororesin varnish has excellent weather resistance, can resist the erosion of extreme environments such as ultraviolet rays, humidity, heat, etc. for a long time, can maintain the stability and beauty of the coating, has good corrosion resistance to a variety of chemical substances, can effectively protect the stainless steel sink from the erosion of substances such as acid, alkali, salt, etc., the formed coating has high hardness and wear resistance, can resist mechanical wear and scratches, extend the service life of the stainless steel sink, can significantly improve the decorative effect and beauty of the stainless steel sink, and give it rich colors and gloss. The coating is easy to clean and maintain, reducing maintenance costs.

[0070] 3) Spraying a wear-resistant layer on the surface of the corrosion-resistant layer in step 2): Using electrostatic spraying technology, evenly apply a wear-resistant silicone varnish material as the wear-resistant layer, and the thickness is controlled between 1-2 microns to ensure that the corrosion-resistant varnish layer is evenly covered, providing sufficient bonding strength and additional protection, and obtaining the above-mentioned multi-layer varnish and composite chromium carbide coating of the stainless steel sink.

[0071] Step 3) Using silicone resin varnish material as the scratch and heat-resistant varnish coating can form a transparent protective film to further protect the stainless steel sink from corrosion and oxidation, thereby better extending the service life, having excellent electrical insulation and thermal stability, and being able to withstand high temperatures of 250°C. At the same time, the hardness can reach 9H, which effectively protects the inner layer of fluororesin varnish from being scratched and damaged by high temperature, and can also improve the fingerprint resistance of stainless steel, making its surface smoother and easier to clean.

[0072] The double-layer varnish coating adopts a wet spraying process. In the wet spraying process, attention should be paid to the humidity, temperature and interval time of the spraying environment. It should be ensured that the first layer is neither too dry nor too wet during wet spraying. Therefore, the requirements of the present invention for the spraying environment are: humidity: 40%-60%, temperature: 25℃-30℃, and the spraying interval is 2min.

[0073] Example 1

[0074] This embodiment provides a surface treatment method for a stainless steel water tank having a multi-layer varnish and a composite chromium carbide coating, comprising:

[0075] Step 1: The surface of the stainless steel sink is plated with a single chromium layer + a chromium nitride layer + a chromium carbonitride layer + a chromium carbide layer (Cr+CrN+CrNC+CrC) using a PVD process to obtain a high-hardness, wear-resistant composite chromium carbide coating.

[0076] Preparation method: Through vacuum coating technology, the single chromium layer, chromium nitride layer, chromium carbonitride layer and chromium carbide coating are evenly covered on the surface of the stainless steel sink to ensure sufficient hardness and improve the overall aesthetics.

[0077] The details are as follows:

[0078] S1: After the surface of the stainless steel water tank (i.e. the substrate layer) is treated by glass sand blasting, it is subjected to ultrasonic degreasing, degumming, cleaning and drying for standby use; a sandblasting layer is obtained.

[0079] Sand blasting: Sand blasting parameters: sand blasting pressure 0.4-0.6MPA; sand blasting line speed: 0.8m / min; surface roughness: Ra greater than 0.8μm.

[0080] Ultrasonic oil removal: Ultrasonic power: 0.8-1.5A; Oil removal time: 100-140s; Oil removal concentration: PH: 9.5-10.5; Total alkali: 16-26pt.

[0081] Cleaning process: 1: water washing; 2: ultrasonic degreasing; 3: water washing; 4: ultrasonic degumming; 5: water washing; 6: pure water washing; 7: 150° high temperature drying.

[0082] S2: Transfer the water tank treated in step S1 into a vacuum furnace, evacuate to 1.0E-2Pa, and heat to 200°C; close the throttle valve of the vacuum furnace, introduce argon gas, turn on 800V high bias, and maintain the duty cycle at 50%; then perform ion glow cleaning for 500s.

[0083] S3: The water tank treated in step S2 is filled with argon gas in a vacuum furnace at a flow rate of 700 sccm, a 500 V bias is turned on, a chromium target is turned on, a chromium target current is 90 A, and a single chromium layer is deposited for 500 s;

[0084] A vacuum furnace was filled with nitrogen gas at a flow rate of 850 sccm, a 200 V bias was turned on, a chromium target was turned on, a chromium target current was 90 A, and a chromium nitride layer was deposited for 500 s.

[0085] A mixed gas of acetylene and nitrogen was filled into a vacuum furnace, the flow rate of acetylene was 450 Sccm, the flow rate of nitrogen was 300 Sccm, a bias of 180 V was turned on, a chromium target was turned on, the chromium target current was 90 A, and a chromium carbonitride layer was deposited for 500 s;

[0086] Fill the vacuum furnace with acetylene at a flow rate of 1100 sccm, turn on a 150 V bias, turn on the chromium target, the chromium target current is 90 A, and deposit a chromium carbide layer for 1500 s.

[0087] After the composite chromium carbide coating is deposited, the vacuum furnace is opened until the temperature drops below 100° C., and the water tank is taken out for standby use; thus, a substrate with the composite chromium carbide coating is obtained.

[0088] Step 2: Spray the corrosion-resistant intermediate layer of fluororesin varnish.

[0089] Preparation method: On the composite chromium carbide coating, electrostatic spraying technology is used to evenly coat the corrosion-resistant fluororesin varnish material as a corrosion-resistant layer, and the thickness is controlled between 1-2 microns to ensure that the corrosion-resistant layer evenly covers the composite chromium carbide coating, which can effectively prevent corrosion of the substrate.

[0090] Step 3: Spray a hard-wearing outer coat of silicone varnish.

[0091] Preparation method: On the corrosion-resistant varnish coating (ie, the corrosion-resistant layer), an electrostatic spraying technology is used to evenly coat a wear-resistant silicone varnish material as a wear-resistant layer, and the thickness is controlled between 1-2 microns to ensure that the wear-resistant layer evenly covers the corrosion-resistant varnish layer (ie, the corrosion-resistant layer) to provide sufficient bonding force and additional protection.

[0092] The double-layer varnish coating adopts wet-spray process, spray room humidity: 40%-60% spray room temperature: 25°-30°; spraying interval: 2 minutes.

[0093] After spraying, cure at 190℃ for 30 minutes.

[0094] Comparative Example 1

[0095] In this comparative example, only step 1 is performed, and steps 2 and 3 are not performed. In step 1, only a single layer of chrome plating, titanium plating or chromium carbide layer is sprayed during coating, and the remaining treatments are the same as those in Example 1.

[0096] Comparative Example 2

[0097] In this comparative example, only step 1 and step 2 are performed, and step 2 and step 3 are not performed. The remaining processes are the same as those in Example 1.

[0098] Comparative Example 3

[0099] In this comparative example, only step 1 and step 2 are performed, and step 3 is not performed. The remaining processes are the same as those in Example 1.

[0100] Comparative Example 4

[0101] In this comparative example, only step 1 and step 3 are performed, and step 2 is not performed. The remaining processes are the same as those in Example 1.

[0102] Comparative Example 5

[0103] This comparative example carries out the processing of step 1, step 3 and step 2, and the rest of the processing is the same as that of Example 1.

[0104] The stainless steel water tank obtained in Example 1 and the stainless steel water tanks obtained in Comparative Examples 1 to 5 were tested, and the testing methods included corrosion resistance testing and friction resistance testing.

[0105] Corrosion resistance test: Soak in 6-degree white vinegar and observe regularly until the coating changes color or falls off.

[0106] Friction resistance test: Use a 1kg weight to act on a 2cm×2cm grinding head. Wrap household steel wool on the surface of the grinding head. Rub the coating surface back and forth at a friction speed of 60 times per minute. The results are shown in Table 1.

[0107] Table 1. Test results

[0108]

[0109]

[0110] As can be seen from Table 1, the present invention significantly improves the wear resistance and corrosion resistance of the stainless steel water tank through the multi-layer varnish coating. Even if the outer varnish is damaged, the middle layer can still effectively protect the substrate from corrosion, thereby extending the service life of the water tank; at the same time, the composite chromium carbide coating of the bottom layer improves the wear resistance of the stainless steel water tank and enriches the appearance of the stainless steel water tank. The design of the multi-layer coating structure makes the functions of each layer complementary, and the overall performance of the water tank is greatly improved.

[0111] As an alternative to the present invention, the present invention can also perform hard chrome electroplating on the surface of the bottom substrate of the stainless steel sink by embossing, and then perform PVD coating on the sink on this basis; through the combination of embossing and hard chrome electroplating technology, the scratch resistance and corrosion resistance of the PVD sink are significantly improved.

[0112] The specific technical solution includes the following steps:

[0113] Embossing treatment on the substrate surface: Embossing treatment is applied to the bottom substrate surface of the stainless steel sink. Embossing can weaken the visual effect of scratches and improve the hardness of the substrate surface. The depth and pattern of embossing are adjusted according to design requirements to achieve the best visual and performance effects.

[0114] Electroplating hard chrome treatment: A layer of hard chrome is electroplated on the surface of the embossed substrate. The hard chrome layer has strong corrosion resistance and high hardness, ensuring that even if the outer coating is damaged, it can still effectively protect the substrate. The electroplating thickness is controlled at about 10 microns to ensure sufficient hardness and corrosion resistance without affecting the overall appearance.

[0115] Sink PVD coating treatment: PVD coating is deposited on the stainless steel sink with hard chrome embossed substrate to provide the overall appearance of the sink and improve the wear resistance of the sink.

[0116] The above is only a preferred embodiment of the present invention, and is not any formal or substantial limitation of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any technician familiar with this profession, without departing from the spirit and scope of the present invention, can make some changes, modifications and evolutions of the technical content disclosed above, which are equivalent embodiments of the present invention; at the same time, any changes, modifications and evolutions of any equivalent changes made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A surface treatment method for a stainless steel water tank, characterized in that: The surface treatment method comprises the following steps: preparing a composite chromium carbide coating on the surface of the substrate layer; Spraying a corrosion-resistant layer on the surface of the composite chromium carbide coating; The wear-resistant layer is sprayed on the surface of the corrosion-resistant layer, and the layer is dried and solidified to obtain a stainless steel water tank with multiple layers of varnish and composite chromium carbide coating.

2. The surface treatment method of a stainless steel water tank according to claim 1, characterized in that: Before preparing the composite chromium carbide coating on the surface of the substrate layer, the method further comprises: The surface of the substrate layer is sandblasted, ultrasonically degreased, de-glued, cleaned and dried for later use; The treated substrate layer was transferred into a vacuum furnace, evacuated to 1.0E-2Pa and heated to 200°C; the throttle valve of the vacuum furnace was closed, argon gas was introduced, 800V high bias was turned on, and the duty cycle was maintained at 50%; ion glow cleaning was performed for 500s.

3. The surface treatment method of a stainless steel water tank according to claim 1, characterized in that: The step of preparing the composite chromium carbide coating on the surface of the substrate layer comprises: Fill the vacuum furnace with argon gas, turn on the bias voltage of 500V, turn on the chromium target, the chromium target current is 90A, deposit the single chromium layer, and the deposition time is 500s; Fill the vacuum furnace with nitrogen, turn on the 200V bias, turn on the chromium target, the chromium target current is 90A, and deposit the chromium nitride layer for 500s; A mixed gas of acetylene and nitrogen was filled into the vacuum furnace, a bias voltage of 180 V was turned on, a chromium target was turned on, a chromium target current was 90 A, and a chromium carbonitride layer was deposited for 500 s. Fill acetylene into the vacuum furnace, turn on the 150V bias, turn on the chromium target, the chromium target current is 90A, deposit the chromium carbide layer, and the deposition time is 1500s; After the deposition is completed, the vacuum furnace is cooled to below 100° C. and then taken out to obtain a substrate having a composite chromium carbide coating.

4. The surface treatment method of a stainless steel water tank according to claim 3, characterized in that: The flow rate of argon gas is 675-725sccm; the flow rate of nitrogen gas is 825-875sccm; in the mixed gas of acetylene and nitrogen, the flow rate of acetylene is 425-475sccm, and the flow rate of nitrogen is 275-325sccm; the flow rate of acetylene is 1075-1125sccm.

5. The surface treatment method of a stainless steel water tank according to claim 1, characterized in that: The method of spraying the corrosion-resistant layer on the surface of the composite chromium carbide coating is to uniformly coat the corrosion-resistant fluororesin varnish material on the surface of the composite chromium carbide coating by electrostatic spraying.

6. The surface treatment method of a stainless steel water tank according to claim 1, characterized in that: The wear-resistant layer is sprayed on the surface of the corrosion-resistant layer by evenly coating the wear-resistant silicone resin varnish material on the surface of the corrosion-resistant layer by electrostatic spraying.

7. A stainless steel water tank, characterized in that: The stainless steel water tank is obtained by the surface treatment method according to any one of claims 1 to 6, comprising a substrate layer (1), the surface of the substrate layer (1) being provided with a sandblasting layer (2), a composite chromium carbide coating (3), a corrosion-resistant layer (4) and a wear-resistant layer (5) in sequence; the composite chromium carbide coating (3) comprises at least 4 layers.

8. A stainless steel water tank with multi-layer varnish and composite chromium carbide coating according to claim 7, characterized in that: The composite chromium carbide coating (3) is composed of a single chromium layer (3-1), a chromium nitride layer (3-2), a chromium carbonitride layer (3-3) and a chromium carbide layer (3-4) in sequence, and the thickness of each layer is 0.3 μm-0.8 μm.

9. A stainless steel water tank with multi-layer varnish and composite chromium carbide coating according to claim 7, characterized in that: The corrosion-resistant layer (4) is a corrosion-resistant fluororesin varnish layer with a thickness of 1 μm-2 μm; the wear-resistant layer (5) is a wear-resistant silicone resin varnish layer with a thickness of 1 μm-2 μm.

10. A surface treatment method for a stainless steel water tank, characterized in that: The treatment method comprises: embossing the bottom substrate surface of the stainless steel water tank, electroplating a layer of hard chrome on the embossed substrate surface, and depositing a PVD coating on the stainless steel water tank with the hard chrome-plated embossed substrate.

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