Anti-corrosion treatment process for metal surface, metal workpiece, electric heating pipe and electric water heater

Abstract

The invention discloses an anti-corrosion treatment process for a metal surface, a metal workpiece, an electric heating tube and an electric water heater, and the anti-corrosion treatment process for the metal surface comprises the following steps: S20, titanium plating is performed on the workpiece to be treated in a deposition manner, so that a titanium compound film is formed on the surface of the workpiece, the deposition manner is a physical vapor deposition manner, and the titanium compound film is formed on the surface of the workpiece; the physical vapor deposition mode is a magnetron sputtering coating mode; and S30, in a high-temperature environment, the titanium element in the titanium compound thin film permeates into the workpiece, so that a titanium alloy layer is formed between the titanium compound thin film and the surface of the workpiece. According to the technical scheme, the corrosion resistance of the metal workpiece can be remarkably improved.

Description

[0001] This application is a divisional application of application number 201811629774.5, filed on December 28, 2018, and entitled “Anti-corrosion treatment process for metal surface, metal workpiece, electric heating tube and electric water heater”. Technical Field

[0002] The present invention relates to the technical field of metal surface treatment, and in particular to an anti-corrosion treatment process for a metal surface, a metal workpiece, an electric heating tube and an electric water heater. Background Art

[0003] According to relevant reports, the annual losses caused by metal corrosion in my country account for 2% to 4% of the gross national product, and the amount of steel scrapped due to corrosion accounts for about 25% to 30% of the annual steel production. For metal materials that are in contact with liquid solutions for a long time, because the metal materials themselves contain impurities, when the liquid solution comes into contact with the metal materials, a galvanic reaction will occur, and the more active metals will lose electrons and be oxidized, resulting in electrochemical corrosion. These corrosion phenomena seriously limit the service life of metal materials. Therefore, finding a good anti-corrosion treatment process for metal surfaces has become one of the important issues that people have to face. Summary of the Invention

[0004] The main purpose of the present invention is to provide an anti-corrosion treatment process for metal surfaces, aiming to improve the corrosion resistance of workpieces.

[0005] To achieve the above-mentioned object, the present invention provides a process for treating metal surfaces with anti-corrosion, comprising the following steps:

[0006] S20, coating the workpiece to be processed with titanium by deposition to form a titanium compound film on the surface of the workpiece;

[0007] S30. In a high-temperature environment, the titanium element in the titanium compound film is infiltrated into the workpiece to form a titanium alloy layer between the titanium compound film and the surface of the workpiece.

[0008] Preferably, before the step S20, the anti-corrosion treatment process for the metal surface further comprises the following steps:

[0009] S10. Sandblasting or polishing the workpiece.

[0010] Preferably, the deposition method is physical vapor deposition.

[0011] Preferably, the physical vapor deposition method is a magnetron sputtering coating method.

[0012] Preferably, when the physical vapor deposition is a magnetron sputtering coating method, the step S20 includes the following steps:

[0013] S210, controlling the vacuum degree and temperature of a vacuum chamber of a vacuum sputtering coating machine to be respectively at a first preset vacuum threshold and a first preset temperature, and performing glow cleaning on a workpiece in the vacuum chamber;

[0014] S211, introducing a protective gas into the vacuum chamber and depositing a titanium film on the workpiece;

[0015] S212. Introduce reaction gas into the vacuum chamber to deposit a titanium compound film on the surface of the workpiece.

[0016] Preferably, the protective gas is argon.

[0017] Preferably, the reaction gas is nitrogen, and the titanium compound film is formed of titanium nitride; or

[0018] The reaction gas is oxygen, and the titanium compound film is formed of titanium oxide.

[0019] Preferably, the first preset vacuum threshold is 1×10 -2 Pa, the first preset temperature is 50°C to 450°C.

[0020] Preferably, the step S30 includes:

[0021] The temperature in the vacuum chamber is controlled at a second preset temperature, and a reaction gas is introduced. After the temperature is kept at a preset time, the furnace is cooled to below 100° C. in a vacuum environment to complete the titanium infiltration treatment.

[0022] Preferably, the second preset temperature is 200° C. to 1000° C., and the preset time is 60 minutes to 200 minutes.

[0023] The present invention further provides a metal workpiece, the surface of which is subjected to an anti-corrosion treatment process for a metal surface, so that a titanium compound film and a titanium alloy layer are formed on the surface of the metal workpiece in sequence from the outside to the inside;

[0024] The anti-corrosion treatment process of the metal surface comprises the following steps:

[0025] S20, coating the workpiece to be processed with titanium by deposition to form a titanium compound film on the surface of the workpiece;

[0026] S30. In a high-temperature environment, the titanium element in the titanium compound film is infiltrated into the workpiece to form a titanium alloy layer between the titanium compound film and the surface of the workpiece.

[0027] Preferably, the thickness of the titanium alloy layer is 0.2 μm to 2 μm; and / or

[0028] The minimum thickness of the titanium compound film is 0.15 μm.

[0029] The present invention also provides an electric heating tube, comprising a metal sleeve and a heating element located in the metal sleeve, wherein the metal sleeve is made of a metal workpiece;

[0030] The surface of the metal workpiece is subjected to an anti-corrosion treatment process for a metal surface, so that a titanium compound film and a titanium alloy layer are sequentially arranged from the outside to the inside on the surface of the metal workpiece;

[0031] The anti-corrosion treatment process of the metal surface comprises the following steps:

[0032] S20, coating the workpiece to be processed with titanium by deposition to form a titanium compound film on the surface of the workpiece;

[0033] S30. In a high-temperature environment, the titanium element in the titanium compound film is infiltrated into the workpiece to form a titanium alloy layer between the titanium compound film and the surface of the workpiece.

[0034] The present invention further provides an electric water heater, comprising an inner tank and an electric heating tube, wherein the electric heating tube is installed in the inner tank, the electric heating tube comprises a metal sleeve and a heating element located in the metal sleeve, and the metal sleeve is made of a metal workpiece;

[0035] The surface of the metal workpiece is subjected to an anti-corrosion treatment process for a metal surface, so that a titanium compound film and a titanium alloy layer are sequentially arranged from the outside to the inside on the surface of the metal workpiece;

[0036] The anti-corrosion treatment process of the metal surface comprises the following steps:

[0037] S20, coating the workpiece to be processed with titanium by deposition to form a titanium compound film on the surface of the workpiece;

[0038] S30. In a high-temperature environment, the titanium element in the titanium compound film is infiltrated into the workpiece to form a titanium alloy layer between the titanium compound film and the surface of the workpiece.

[0039] The outermost side of the workpiece treated by the anti-corrosion treatment process according to the technical solution of the present invention has a layer of titanium compound film. The titanium compound film is very dense and will not produce pinhole defects. Its anti-corrosion effect is more reliable, thus having better super corrosion resistance. The titanium compound itself has a high melting point, and the titanium compound film formed has the characteristics of high temperature resistance and high burning resistance; the titanium compound has a high thermal conductivity coefficient, and the titanium compound film formed has better thermal conductivity than the existing anti-corrosion coating; the titanium alloy itself also has the metallic properties of titanium, that is, the titanium alloy has better anti-corrosion performance. It is worth noting that the cost of titanium alloy is much lower than that of pure titanium, and thus the processing cost of the workpiece can also be reduced; the titanium alloy layer is formed by infiltrating the titanium element in the titanium compound film into the workpiece, and thus the combination of the titanium compound film, titanium alloy and workpiece is very firm, and its anti-corrosion structure is very stable and highly reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0041] Figure 1 This is a schematic structural diagram of an embodiment of a metal workpiece according to the present invention;

[0042] Figure 2 A flow chart of a preferred embodiment of the anti-corrosion treatment process for metal surfaces of the present invention;

[0043] Figure 3 This is a process flow chart for the use of magnetron sputtering coating in the anti-corrosion treatment process for metal surfaces of the present invention;

[0044] Figure 4 This is a schematic diagram of the internal structure of an electric heating tube according to an embodiment of the present invention;

[0045] Figure 5 for Figure 4 A partial enlarged view of point A in the middle;

[0046] Figure 6 for Figure 4 Schematic diagram of the layer structure of the metal casing.

[0047] Description of Figure Numbers:

[0048] Label name Label name 10 Metal workpieces 102 Titanium alloy layer 101 Titanium compound thin films 20 Electric heating tube 210 Metal casing 230 Thermally conductive insulating materials 220 Heating element

[0049] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0051] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0052] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text is to include three parallel solutions. Taking "A and / or B" as an example, it includes Solution A, or Solution B, or a solution in which both A and B are satisfied. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] The invention provides an anti-corrosion treatment process for metal surfaces.

[0054] In one embodiment of the present invention, referring to Figures 1 to 4 The anti-corrosion treatment process of the metal surface includes the following steps:

[0055] S20, coating the workpiece to be processed with titanium by deposition to form a titanium compound film 101 on the surface of the workpiece;

[0056] S30 . In a high-temperature environment, the titanium element in the titanium compound film 101 is infiltrated into the workpiece to form a titanium alloy layer 102 between the titanium compound film 101 and the surface of the workpiece.

[0057] Specifically, the workpiece may be a metal part such as stainless steel, carbon steel, copper, or iron. There are various ways to deposit titanium on the workpiece, such as by forming a titanium compound film 101 on the surface of the workpiece through physical vapor deposition, chemical vapor deposition, or the like. Under high temperature conditions, a titanium infiltration process may be used to combine the titanium element in the titanium compound film 101 with the metal element in the workpiece to form a titanium alloy. This means that the titanium element in the titanium compound film 101 penetrates into the workpiece, forming a titanium alloy layer 102 between the titanium compound film 101 and the surface of the workpiece.

[0058] After the aforementioned anti-corrosion treatment process, the workpiece is coated with a titanium compound film 101 on its outermost surface. This titanium compound film 101 is highly dense, free of pinhole defects, and offers a more reliable anti-corrosion effect, resulting in superior corrosion resistance. Titanium compounds themselves have a high melting point, resulting in the resulting titanium compound film 101 being resistant to high temperatures and high temperatures. Furthermore, titanium compounds have a high thermal conductivity, resulting in a superior thermal conductivity compared to existing anti-corrosion coatings.

[0059] Titanium alloys also have the metallic properties of titanium, that is, titanium alloys have excellent corrosion resistance. It is worth noting that the cost of titanium alloys is much lower than that of pure titanium, which can also reduce the processing cost of workpieces.

[0060] It should be emphasized that, compared with the conventional method of spraying an anti-corrosion coating on the workpiece, in this embodiment, since the titanium alloy layer 102 is formed by infiltrating the titanium element in the titanium compound film 101 into the workpiece, the titanium compound film 101, the titanium alloy and the workpiece are firmly bonded together, and its anti-corrosion structure is very stable and highly reliable.

[0061] Furthermore, in order to better perform corrosion protection on the workpiece, in this embodiment, before performing the above-mentioned step S20, the workpiece surface may be preferably pretreated so as to better deposit a thin film on the workpiece surface. The pretreatment step is specifically as follows:

[0062] S10, sandblasting or polishing the workpiece, and then ultrasonically cleaning and drying the workpiece.

[0063] By performing the above-mentioned pretreatment steps, impurities attached to the surface of the workpiece can be cleaned and the surface smoothness of the workpiece can be improved, thereby being more conducive to the deposition and formation of the titanium compound film 101 on the surface of the workpiece.

[0064] The physical vapor deposition technology has a simple process, is environmentally friendly, pollution-free, requires few consumables, forms a uniform and dense film, and has strong bonding with the substrate. Therefore, in this embodiment, the titanium compound film is preferably formed on the surface of the workpiece by physical vapor deposition. Physical vapor deposition coating methods mainly include three categories: vacuum evaporation, magnetron sputtering, and multi-arc ion plating. Correspondingly, the corresponding coating equipment also includes three types: vacuum evaporation coating machine, vacuum sputtering coating machine, and vacuum ion plating machine.

[0065] In a preferred embodiment, referring to Figure 3 , the magnetron sputtering coating method is used for coating, that is, a vacuum sputtering coating machine is used to coat the workpiece. At this time, the above step S20 specifically includes the following steps:

[0066] S210, controlling the vacuum degree and temperature of the vacuum chamber of the magnetron sputtering device to be respectively at a first preset vacuum threshold and a first preset temperature, and performing glow cleaning on the workpiece in the vacuum chamber;

[0067] S211, introducing a protective gas into the vacuum chamber and depositing a titanium film on the workpiece;

[0068] S212 , introducing reaction gas into the vacuum chamber to deposit and form a titanium compound film 101 on the surface of the workpiece.

[0069] It is understood that the workpiece is placed in the vacuum chamber of the vacuum sputtering coating machine, the titanium target is mounted on the vacuum sputtering coating machine, the vacuum pumping system of the vacuum sputtering coating machine is started, the vacuum degree in the vacuum chamber is made less than the first preset vacuum threshold, and then the heating device of the vacuum sputtering coating machine is turned on to heat the vacuum chamber and control the indoor temperature of the vacuum chamber within the first preset temperature. In this embodiment, the first preset vacuum threshold is preferably 1×10 -2 Pa, the first preset temperature is preferably 50° C. to 450° C., and the purity of the titanium target is preferably above 99.9%.

[0070] When glow cleaning the workpiece, argon gas with a purity of more than 99.9% is passed into the vacuum chamber and the pressure is controlled at 2×10 -1 Pa~3×10 -1 Pa, the bias power supply is turned on and controlled in the range of -200V to -700V, causing the gas to generate glow discharge to perform glow cleaning on the surface of the metal workpiece 10. The glow cleaning time is 2 to 20 minutes. In order to improve both the efficiency and cleanliness of the glow cleaning, in this embodiment, the glow cleaning time is preferably controlled to be 5 to 10 minutes.

[0071] When depositing a titanium film on a workpiece, the protective gas can be an inert gas such as argon, neon, or xenon, preferably argon, thereby reducing the cost of additional gas sources required for the vacuum sputtering coating machine. In the above step S211, it is preferred that argon with a purity of more than 99.9% be introduced into the vacuum chamber, and the gas pressure be controlled at 2×10 -1 Pa~3×10 -1 Pa, and at the same time, the target power supply of the vacuum sputtering coating machine is turned on, the workpiece bias voltage is controlled at -300V to -700V, and a titanium film is deposited on the surface of the workpiece for 2 to 20 minutes.

[0072] The reaction gas may be oxygen or nitrogen. In the above step S212, nitrogen or oxygen is introduced into the vacuum chamber, wherein the flow rate of nitrogen or oxygen is controlled at 1060 cm 3 / S~60cm 3 / S, the air pressure is controlled at 2×10 -1 Pa~3×10 -1 Pa, the workpiece bias voltage is controlled between -100V and -1500V, the target power supply is turned on, and titanium nitride or titanium oxide thin films are deposited for 20 to 100 minutes; after the deposition is completed, the target power switch is quickly turned off. It can be understood that when oxygen is introduced into the vacuum chamber, the titanium film and oxygen react chemically to form a titanium oxide film; when nitrogen is introduced into the vacuum chamber, the titanium film and nitrogen react chemically to form a titanium nitride film.

[0073] Furthermore, after the magnetron sputtering coating method is used for coating, the workpiece can be immediately subjected to high-temperature titanium infiltration treatment, that is, the above-mentioned step S30 includes:

[0074] The temperature in the vacuum chamber is controlled at a second preset temperature, and a reaction gas is introduced. After the temperature is kept at a preset time, the titanium infiltration treatment is completed by cooling the furnace to below 100° C. under a vacuum environment.

[0075] Specifically, in this embodiment, the second preset temperature is preferably 200°C to 1000°C. At this time, oxygen or nitrogen with a purity of 99.9% or higher is introduced into the vacuum chamber, kept at this temperature for 60 to 200 minutes, and then cooled to below 100°C in a vacuum environment. It can be understood that during this process, the titanium compound film 101 is subjected to high-temperature treatment, causing the titanium element to diffuse from the outside to the inside of the workpiece, and then combine with the metal elements of the workpiece to form a titanium alloy.

[0076] Reference Figure 1The present invention also proposes a metal workpiece 10, which is made by an anti-corrosion treatment process on the metal surface. The surface of the metal workpiece 10 has a titanium compound film 101 and a titanium alloy layer 102 arranged in sequence from the outside to the inside. The specific steps of the anti-corrosion treatment process on the metal surface refer to the above embodiment. Since the metal workpiece 10 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0077] Furthermore, for the metal workpiece 10 treated with the above-mentioned anti-corrosion treatment process, the minimum thickness of its titanium compound film 101 is preferably 0.15μm, which ensures that the titanium compound film 101 has sufficient thickness, ensures that the titanium compound film 101 has good corrosion resistance, dry burning resistance and reliability, and makes the performance of the titanium compound film 101 reach the best; the thickness of its titanium alloy layer 102 is preferably 0.2μm~2μm, thereby ensuring that the titanium alloy layer 102 has better corrosion resistance and reduces the manufacturing cost of the product.

[0078] The metal workpiece 10 treated with the anti-corrosion treatment process can be used in a variety of applications, such as heating sleeves for electric water heaters. When the metal workpiece 10 is a heating sleeve, the workpiece is processed into a tubular shape, and then the outer surface of the metal tube is treated with the metal surface anti-corrosion treatment process described above. The resulting heating sleeve has excellent corrosion resistance, good thermal conductivity, high reliability, dry burning resistance, and low cost.

[0079] Reference Figures 4 to 6 The present invention further provides an electric heating tube 20 comprising a metal sleeve 210 and a heating element 220 located within the metal sleeve 210. The metal sleeve 210 is made of a metal workpiece 10. The specific structure and manufacturing method of the metal workpiece 10 are similar to those of the above-mentioned embodiments. Since the electric heating tube 20 adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described in detail here. It is understood that, during the manufacturing process of the metal sleeve 210, before the metal workpiece 10 undergoes the above-mentioned anti-corrosion treatment process, it is first formed into a tubular shape and then subjected to the anti-corrosion treatment.

[0080] It is understood that the outer surface of the metal sleeve 210 has a titanium compound film 101 and a titanium alloy layer 102 arranged sequentially from the outside to the inside. In this embodiment, to improve the safety performance of the electric heating tube 20, a thermally conductive insulating material 230 is filled between the heating element 220 and the inner wall of the metal sleeve 210. This forms an electrical isolation between the heating element 220 and the metal sleeve 210, that is, the electric heating tube 20 has a water-electric isolation effect, thereby reducing the risk of electric shock.

[0081] The present invention also proposes an electric water heater, which includes an inner tank and an electric heating tube. The electric heating tube is installed in the inner tank. The specific structure of the electric heating tube refers to the above embodiment. Since this electric water heater adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0082] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A metal surface anti-corrosion treatment process, characterized in that: The following steps are involved: S20, coating the workpiece to be processed with titanium by a deposition method to form a titanium compound thin film on the surface of the workpiece, wherein the deposition method is a physical vapor deposition method, and the physical vapor deposition method is a magnetron sputtering coating method; S30. In a high-temperature environment, the titanium element in the titanium compound film is infiltrated into the workpiece to form a titanium alloy layer between the titanium compound film and the surface of the workpiece.

2. The anti-corrosion treatment process according to claim 1, characterized in that: Before the step S20, the anti-corrosion treatment process for the metal surface further includes the following steps: S10. Sandblasting or polishing the workpiece.

3. The anti-corrosion treatment process according to claim 1 or 2, characterized in that: The step S20 includes the following steps: S210, controlling the vacuum degree and temperature of a vacuum chamber of a vacuum sputtering coating machine to be respectively at a first preset vacuum threshold and a first preset temperature, and performing glow cleaning on a workpiece in the vacuum chamber; S211, introducing a protective gas into the vacuum chamber and depositing a titanium film on the workpiece; S212. Introduce reaction gas into the vacuum chamber to deposit a titanium compound film on the surface of the workpiece.

4. The anti-corrosion treatment process according to claim 3, characterized in that: The first preset vacuum threshold is 1×10 -2 Pa, the first preset temperature is 50°C to 450°C.

5. The anti-corrosion treatment process according to claim 3, characterized in that: The protective gas is argon.

6. The anti-corrosion treatment process according to claim 3, characterized in that: The reaction gas is nitrogen, and the titanium compound film is formed of titanium nitride; or The reaction gas is oxygen, and the titanium compound film is formed of titanium oxide.

7. The anti-corrosion treatment process according to claim 1, characterized in that: The step S30 includes: controlling the temperature in the vacuum chamber to a second preset temperature, introducing a reaction gas, maintaining the temperature for a preset time, and then cooling the chamber to below 100° C. in a vacuum environment to complete the titanium infiltration process.

8. The anti-corrosion treatment process according to claim 7, characterized in that: The second preset temperature is 200° C. to 1000° C., and the preset time is 60 minutes to 200 minutes.

9. A metal workpiece, characterized in that: The surface of the metal workpiece is anti-corrosion treated using the anti-corrosion treatment process according to any one of claims 1 to 8, so that a titanium compound film and a titanium alloy layer are formed on the surface of the metal workpiece in sequence from the outside to the inside.

10. The metal workpiece according to claim 9, characterized in that The thickness of the titanium alloy layer is 0.2 μm to 2 μm; and / or The minimum thickness of the titanium compound film is 0.15 μm.

11. The metal workpiece according to claim 9 or 10, characterized in that The metal workpiece includes stainless steel, carbon steel, copper or iron.

12. An electric heating tube, characterized in that: It comprises a metal sleeve and a heating element located in the metal sleeve, wherein the metal sleeve is made according to the metal workpiece according to claims 9-11.

13. An electric water heater, characterized in that: It comprises an inner container and the electric heating tube as claimed in claim 12, wherein the electric heating tube is installed in the inner container.

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