Galvanic corrosion protection method and galvanic corrosion prevention magnesium-containing connecting assembly

Abstract

The invention belongs to the technical field of magnesium alloy corrosion prevention, and particularly relates to a galvanic corrosion protection method and a galvanic corrosion prevention magnesium-containing connecting assembly, the galvanic corrosion protection method and the galvanic corrosion prevention magnesium-containing connecting assembly are applied to galvanic corrosion formed by contact of a magnesium alloy structural part and a dissimilar metal connecting part, and the galvanic corrosion protection method comprises the steps that firstly, chemical conversion film treatment is conducted on the magnesium alloy structural part (1); 2, carrying out first coating anti-corrosion treatment on the dissimilar metal connecting piece (2) and the fastening assembly; 3, coating a structural adhesive (6) on a contact binding surface formed between the magnesium alloy structural part (1) subjected to the chemical conversion film treatment and the dissimilar metal connecting part (2) subjected to the first coating anti-corrosion treatment; and fourthly, the magnesium alloy structural part (1) and the dissimilar metal connecting part (2) with the contact binding face coated with the structural adhesive (6) are locked through the fastening combination part, an assembly part is formed, and second coating anti-corrosion treatment is conducted on the assembly part. By adopting the method, the galvanic corrosion risk is greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of magnesium alloy anti-corrosion, and in particular relates to a galvanic corrosion protection method and a magnesium-containing connection component for preventing galvanic corrosion. Background Art

[0002] Galvanic corrosion refers to the phenomenon that when two or more metals come into contact with each other in the same corrosive medium, galvanic current is generated due to the different corrosion potentials of dissimilar metals, thereby causing electrochemical corrosion. It is also called contact corrosion. Galvanic corrosion is a potential, extremely extensive and serious type of corrosion that causes accelerated corrosion of low-potential materials (such as steel, copper, etc.). Its occurrence and development are often accompanied by a variety of local corrosion, which accelerates the destruction of equipment, seriously threatens the safety and reliability of various application equipment, and causes serious losses. At present, more and more structural parts are made of magnesium alloys as raw materials, which also makes it inevitable that magnesium alloys come into contact with dissimilar metals (such as stainless steel fasteners and plates) or even make electrical connections. However, due to the large potential difference between magnesium alloys (about -2.363V) and dissimilar metals (such as steel potential of about -0.441V), magnesium alloys often suffer from severe galvanic corrosion. How to prevent magnesium alloys from corrosion has become an important issue.

[0003] From the principle of galvanic corrosion, it can be known that the occurrence of galvanic corrosion must have the following points at the same time: (1) potential difference, that is, the existence of two materials with different corrosion potentials; (2) electron path, that is, direct contact between heterogeneous materials; (3) ion path, that is, heterogeneous materials covered or immersed in electrolyte. Based on this principle, galvanic corrosion protection can be carried out by reducing the potential difference or blocking the electron or ion path. For the galvanic corrosion problem caused by the connection between magnesium alloy and dissimilar metals, it is generally adopted to apply glue to the entire area of ​​the connection surface after the connection to isolate the external corrosive medium and reduce the risk of galvanic corrosion. This method has the defects of uncontrolled glue application or insufficient space for glue application facilities during implementation. In addition, there is also a prior art that discloses that by pre-embedding a threaded sleeve in the magnesium alloy matrix and placing a non-metallic sheath in the connected part, the connection fastener and the magnesium alloy are not in contact, eliminating the risk of galvanic corrosion. However, this method has a high implementation cost, is not suitable for locking large-size fasteners, and is not universal.

[0004] Based on this, the present invention aims to provide a galvanic corrosion protection method and a magnesium-containing connection component that is galvanic corrosion-resistant, targeting the galvanic corrosion formed when magnesium alloys are connected to dissimilar metals. Summary of the invention

[0005] The present invention aims to provide a galvanic corrosion protection method and a magnesium-containing connection component for preventing galvanic corrosion caused by the connection of a magnesium alloy with a dissimilar metal.

[0006] According to a first aspect of the present invention, the present invention provides a galvanic corrosion protection method, which is applied to galvanic corrosion formed by contact between a magnesium alloy structural part and a dissimilar metal connecting part, and the galvanic corrosion protection method comprises:

[0007] 1. performing chemical conversion film treatment on the magnesium alloy structural part to form a chemical conversion film on the surface of the magnesium alloy structural part;

[0008] 2. performing a first coating anti-corrosion treatment on the dissimilar metal connector and the fastening assembly, and forming a first anti-corrosion coating on the surfaces of the dissimilar metal connector and the fastening assembly respectively;

[0009] 3. coating a structural adhesive on the contact bonding surface formed between the magnesium alloy structural part treated with the chemical conversion film and the dissimilar metal connecting part treated with the first coating for corrosion protection;

[0010] Fourth, the fastening assembly is used to lock the magnesium alloy structural part and the dissimilar metal connecting part whose contact surfaces are coated with structural adhesive to form an assembly part, and the assembly part is subjected to a second coating anti-corrosion treatment to form a second anti-corrosion coating on the surface of the assembly part.

[0011] With regard to the problem that galvanic corrosion is easily generated when magnesium alloy structural parts contact with dissimilar metal connectors, most of the existing technologies adopt the method of coating the magnesium alloy surface with glue in the entire area. This method for galvanic corrosion protection has defects such as uncontrolled glue coating amount or insufficient space for glue coating facilities. At the same time, the protection effect for galvanic corrosion also has certain limitations. Based on this, the present invention provides a galvanic corrosion protection method for the problem of galvanic corrosion formed when magnesium alloy structural parts contact with dissimilar metal connectors. First, the method provided by the present invention includes first performing a chemical conversion film treatment on the surface of the magnesium alloy structural part to form a chemical conversion film on the surface of the magnesium alloy structural part, and then performing a first coating anti-corrosion treatment on the dissimilar metal connector and the fastening assembly, so that a first anti-corrosion coating is formed on the surfaces of the dissimilar metal connector and the fastening assembly, respectively. Such a design can achieve physical isolation of all part substrates from the external environment, thereby achieving a better anti-galvanic corrosion effect. Furthermore, the present invention has found through research that, in the case where the fastening assembly is not subjected to coating anti-corrosion treatment, severe galvanic corrosion will occur between the dissimilar metal connectors and the magnesium alloy structural parts. Furthermore, if the dissimilar metal connectors and fastening connectors are subjected to chemical conversion film treatment in advance instead of the first coating anti-corrosion treatment, it will also cause the dissimilar metal connectors and fastening connectors to fail prematurely and contact with magnesium to form galvanic corrosion. The present invention chooses to first treat the surface of the magnesium alloy with a chemical conversion film and to perform the first coating anti-corrosion treatment on the dissimilar metal connectors and the fastening assembly, which effectively avoids galvanic corrosion between the bonding surfaces of the dissimilar metal connectors and the magnesium alloy structural parts. Secondly, the present invention can achieve quantitative positioning coating by applying structural adhesive to the contact bonding surfaces formed between the magnesium alloy structural parts treated with the chemical conversion film and the dissimilar metal connectors treated with the first coating anti-corrosion treatment, which can be fully controlled to enhance the anti-galvanic corrosion capability, and can further achieve physical isolation on the basis of ensuring the connection strength. Furthermore, the present invention locks the magnesium alloy structural part and the dissimilar metal connecting part whose contact surfaces are coated with structural adhesive by the fastening assembly to form an assembly, and then performs a second coating anti-corrosion treatment on the assembly. After the connection is completed, the locking integrated structure is subjected to an overall electrophoresis treatment, which can also have a certain degree of sealing effect on the connection surfaces of the components, further increasing the corrosion resistance of the entire magnesium-containing connection component structure.

[0012] In some embodiments of the present invention, in step one, the chemical conversion film treatment step includes: performing passivation treatment and sealing treatment on the magnesium alloy structural part.

[0013] In some embodiments of the present invention, the passivation treatment includes: performing activation pretreatment and phosphate passivation on the magnesium alloy structural member to form a fine granular phosphating film.

[0014] In some embodiments of the present invention, the sealing treatment comprises: filling and sealing the pores of the magnesium alloy structural member (1) to form a uniformly distributed organic sealing layer.

[0015] In the chemical conversion film treatment of the magnesium alloy structural parts, the present invention adds an inorganic sealing layer, which includes an inorganic pore-filling layer and a sealing layer. The inorganic pore-filling layer can increase the density of the chemical conversion film to enhance the corrosion resistance, and the sealing layer can increase the conductivity and the total film thickness of the protective layer to ensure 100% implementation of the electrophoresis process. In addition, by adopting this method, the contamination of magnesium ions in the pretreatment tank solution can be reduced, thereby increasing the versatility of the process implementation.

[0016] In some embodiments of the present invention, the chemical conversion film comprises: phosphates.

[0017] In some embodiments of the present invention, the thickness of the chemical conversion film is: <10 um.

[0018] In some embodiments of the present invention, in step 2, the first coating anti-corrosion treatment includes at least one of black electrophoresis, zinc-aluminum coating, electroplating zinc, and electroplating zinc-nickel.

[0019] In some embodiments of the present invention, the thickness of the first anti-corrosion coating is: 8-25um; when the anti-corrosion treatment method of the first coating is black electrophoresis, the thickness of the first anti-corrosion coating is >15um; when the anti-corrosion treatment method of the first coating is zinc-aluminum coating, the thickness of the first anti-corrosion coating is 8-25um; when the anti-corrosion treatment method of the first coating is electroplating zinc, the thickness of the first anti-corrosion coating is 8-15um; when the anti-corrosion treatment method of the first coating is electroplating zinc-nickel, the thickness of the first anti-corrosion coating is 8-15um.

[0020] In some embodiments of the present invention, when the first coating is treated with black electrophoresis for anti-corrosion, the components of the first anti-corrosion coating are resin and pigment; when the first coating is treated with zinc-aluminum coating for anti-corrosion, the components of the first anti-corrosion coating include: flaky zinc powder, flaky aluminum powder and inorganic binder; when the first coating is treated with zinc electroplating for anti-corrosion, the component of the first anti-corrosion coating is pure zinc; when the first coating is treated with zinc-nickel electroplating for anti-corrosion, the component of the first anti-corrosion coating is zinc-nickel alloy, wherein the weight proportion of nickel in the zinc-nickel alloy is 12-18%.

[0021] In some embodiments of the present invention, the dissimilar metal connector is a metal formed by any one of the metal elements of aluminum, zinc, iron, titanium, tin, lead, copper, silver, platinum and gold, or an alloy formed by any two or more of the metal elements of aluminum, zinc, iron, titanium, tin, lead, copper, silver, platinum and gold.

[0022] In some embodiments of the present invention, the structural adhesive is selected from epoxy resin. The structural adhesive is applied to the contact surfaces formed between the magnesium alloy structural parts and the dissimilar metal connectors, which can achieve quantitative positioning coating and be fully controlled, and can greatly improve the anti-galvanic corrosion capability.

[0023] In some embodiments of the present invention, the thickness of the structural adhesive is: <0.5 mm. The use of structural adhesive with the above thickness can greatly reduce the risk of galvanic corrosion on the bonding surface.

[0024] In some embodiments of the present invention, in step four, the fastening connector includes a connecting fastener, a metal gasket and a non-metallic gasket, the outer diameter of the non-metallic gasket is larger than the outer diameter of the connecting fastener and the metal gasket, the metal gasket is arranged between the connecting fastener and the dissimilar metal connector, and the non-metallic gasket is arranged between the metal gasket and the dissimilar metal connector. Select a non-metallic gasket of suitable specifications so that the metal gasket and the dissimilar metal connector are not in direct contact, and finally ensure that the non-metallic gasket completely isolates the entire locking connection point from the external corrosive environment by setting a reasonable pre-tightening torque, so that galvanic corrosion cannot be formed. In the scheme provided by the present invention, non-metallic gaskets of various specifications can be provided to match the connecting fasteners and metal gaskets, and the purpose of pre-tightening can be easily achieved. Compared with the prior art that discloses the use of embedded threaded sleeves and non-metallic sheaths or the operation of applying glue after connection, the present invention sets a non-metallic gasket of suitable specifications to isolate the metal gasket from the dissimilar metal connector, which cannot form galvanic corrosion and also improves the installation efficiency.

[0025] In some embodiments of the present invention, the fastening connector is to subject the fastener and metal gasket to a first coating anti-corrosion treatment, and after forming a first anti-corrosion coating on the surface of the fastener and metal gasket, respectively, the fastening connector is assembled with the non-metallic gasket to form the fastening connector. The present invention has found through research that if dissimilar metal connectors, metal gaskets, etc. are not subjected to coating anti-corrosion treatment, dissimilar metal connectors and magnesium alloy structural parts will form severe galvanic corrosion, and the above-mentioned method of the present invention can effectively avoid galvanic corrosion of the contact and fitting surfaces of dissimilar metal connectors and magnesium alloy structural parts.

[0026] In some embodiments of the present invention, the fastening assembly is used to lock the magnesium alloy structural part and the dissimilar metal connecting part whose contact surfaces are coated with structural adhesive to form an assembly, which includes: according to a preset locking torque, the connecting fastener is sequentially passed through the metal gasket, the non-metallic gasket, the dissimilar metal connecting part and the magnesium alloy structural part for locking connection, and the fastening assembly and the dissimilar metal connecting part and the magnesium alloy structural part are locked as one, so as to obtain an assembly formed by the magnesium alloy structural part, the dissimilar metal connecting part and the fastening assembly.

[0027] In some embodiments of the present invention, in step 4, the fastening assembly is locked to the magnesium alloy structural member and the dissimilar metal connector whose contact surfaces are coated with structural adhesive to form an assembly, which includes: according to a preset locking torque, the connecting fastener is sequentially passed through the metal gasket, the non-metallic gasket, the dissimilar metal connector, and the magnesium alloy structural member for locking connection, to obtain an assembly formed by the connecting fastener, the metal gasket, the non-metallic gasket, the magnesium alloy structural member, and the dissimilar metal connector. The above connection method can greatly reduce the risk of galvanic corrosion between the magnesium alloy structural member and the dissimilar metal connector. At the same time, the present invention provides a variety of non-metallic gaskets of various specifications to match the connecting fasteners and metal gaskets, which can easily achieve the purpose of pre-tightening. According to the connection method designed by this technical solution, the connection sequence of the magnesium alloy structural member and the dissimilar metal connector can be changed, so that the connection of the upper dissimilar metal connector and the lower magnesium alloy structural member or the upper magnesium alloy structural member and the lower dissimilar metal connector can be achieved, and the risk of galvanic corrosion can be avoided.

[0028] In some embodiments of the present invention, the second coating is treated for corrosion by electrophoresis.

[0029] In some embodiments of the present invention, the anti-corrosion treatment method of the second coating includes pre-treating the assembly before performing the electrophoresis; the pre-treatment includes water washing and thin film process treatment.

[0030] According to a second aspect of the present invention, the present invention further provides a magnesium-containing connection component that is resistant to galvanic corrosion, the magnesium-containing connection component comprising:

[0031] A magnesium alloy structural part, the surface of which is coated with a chemical conversion film;

[0032] A dissimilar metal connector, the surface of which is coated with a first anti-corrosion coating;

[0033] Structural adhesive is coated on the contact bonding surface between the magnesium alloy structural part with the chemical conversion film on the surface and the dissimilar metal connecting part with the first anti-corrosion coating on the surface;

[0034] A fastening connector, the surface of which is coated with a first anti-corrosion coating, through which the dissimilar metal connector is connected to the magnesium alloy structural part, the fastening assembly and the dissimilar metal connector and the magnesium alloy structural part are locked as one, thereby obtaining the magnesium-containing connection component, the surface of which is coated with a second anti-corrosion coating.

[0035] In some embodiments of the present invention, the fastening connector includes a connecting fastener, a metal gasket and a non-metallic gasket; in some embodiments of the present invention, the outer diameter of the non-metallic gasket is larger than the outer diameters of the connecting fastener and the metal gasket; the metal gasket is arranged between the connecting fastener and the heterogeneous metal connector, and the non-metallic gasket is arranged between the metal gasket and the heterogeneous metal connector.

[0036] In some embodiments of the present invention, the connecting fastener passes through the metal gasket, non-metallic gasket, dissimilar metal connecting piece and the magnesium alloy structural part in sequence to connect, and the fastening assembly and the dissimilar metal connecting piece and the magnesium alloy structural part are locked together to obtain the magnesium-containing connecting component.

[0037] In some embodiments of the present invention, the surfaces of the connecting fasteners and the metal gaskets are respectively coated with a first anti-corrosion coating.

[0038] In some embodiments of the present invention, the material of the non-metallic gasket is selected from at least one of polyurethane materials, epoxy resin materials and steel paper materials.

[0039] In some embodiments of the present invention, the chemical conversion film comprises a phosphate substance; and the thickness of the chemical conversion film is less than 10 um.

[0040] In some embodiments of the present invention, the thickness of the first anti-corrosion coating is: 8-25um; when the anti-corrosion treatment method of the first coating is black electrophoresis, the thickness of the first anti-corrosion coating is >15um; when the anti-corrosion treatment method of the first coating is zinc-aluminum coating, the thickness of the first anti-corrosion coating is 8-25um; when the anti-corrosion treatment method of the first coating is electroplating zinc, the thickness of the first anti-corrosion coating is 8-15um; when the anti-corrosion treatment method of the first coating is electroplating zinc-nickel, the thickness of the first anti-corrosion coating is 8-15um.

[0041] In some embodiments of the present invention, when the first coating is treated with black electrophoresis for anti-corrosion, the components of the first anti-corrosion coating are resin and pigment; when the first coating is treated with zinc-aluminum coating for anti-corrosion, the components of the first anti-corrosion coating include: flaky zinc powder, flaky aluminum powder and inorganic binder; when the first coating is treated with zinc electroplating for anti-corrosion, the component of the first anti-corrosion coating is pure zinc; when the first coating is treated with zinc-nickel electroplating for anti-corrosion, the component of the first anti-corrosion coating is zinc-nickel alloy, wherein the weight proportion of nickel in the zinc-nickel alloy is 12-18%.

[0042] In some embodiments of the present invention, the structural adhesive is selected from epoxy resins.

[0043] In some embodiments of the present invention, the thickness of the structural adhesive is: <0.5 mm.

[0044] In some embodiments of the present invention, the components of the second anti-corrosion coating include: resin and pigment.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention provides a galvanic corrosion protection method, which can greatly reduce the galvanic corrosion risk of magnesium alloy structural parts and dissimilar metal connections. Before connection, anti-corrosion coating protection is adopted for magnesium alloy structural parts, dissimilar metal connectors, and fastening connectors to achieve physical isolation of all parts substrates from the external environment; during the connection process, structural adhesive is applied between the magnesium alloy structural parts and the dissimilar metal connectors to achieve physical isolation on the basis of ensuring the connection strength, and finally a reasonable pre-tightening torque is set to ensure that the fastening connector completely isolates the entire locking connection point from the external corrosion environment, so that galvanic corrosion cannot be formed; after the connection is completed, the locking integrated structure is subjected to electrophoresis treatment of the overall anti-corrosion coating to further increase the corrosion resistance of the entire structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A magnesium-containing connection component for preventing galvanic corrosion provided by one embodiment of the present invention;

[0048] Figure numerals: 1-magnesium alloy structural part; 2-dissimilar metal connecting part; 3-connecting fastener; 4-metal gasket; 5-non-metal gasket; 6-structural adhesive. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific embodiments, which do not limit the protection scope of the present invention. Some non-essential modifications and adjustments made by others based on the concept of the present invention still fall within the protection scope of the present invention.

[0050] With regard to the galvanic corrosion problem caused by the connection between magnesium alloy and dissimilar metals, and in view of the problems existing in the prior art methods of applying glue to the entire connection surface after connection or pre-embedding threaded sleeves in the magnesium alloy matrix, placing non-metallic sheaths in the connected parts, the present invention provides a galvanic corrosion protection method and a magnesium-containing connection component that is resistant to galvanic corrosion.

[0051] According to a first aspect of the present invention, the present invention provides a galvanic corrosion protection method, which is applied to galvanic corrosion formed by contact between a magnesium alloy structural part and a dissimilar metal connecting part, and the galvanic corrosion protection method comprises:

[0052] 1. performing chemical conversion film treatment on the magnesium alloy structural part to form a chemical conversion film on the surface of the magnesium alloy structural part;

[0053] 2. performing a first coating anti-corrosion treatment on the dissimilar metal connector and the fastening assembly, and forming a first anti-corrosion coating on the surfaces of the dissimilar metal connector and the fastening assembly respectively;

[0054] 3. coating a structural adhesive on the contact bonding surface formed between the magnesium alloy structural part treated with the chemical conversion film and the dissimilar metal connecting part treated with the first coating for corrosion protection;

[0055] Fourth, the fastening assembly is used to lock the magnesium alloy structural member and the dissimilar metal connecting member whose contact surfaces are coated with structural adhesive to form an assembly, and the assembly is subjected to a second coating anti-corrosion treatment to form a second anti-corrosion coating on the surface of the assembly.

[0056] With regard to the problem that galvanic corrosion is easily generated when magnesium alloy structural parts contact with dissimilar metal connectors, most of the existing technologies adopt the method of coating the magnesium alloy surface with glue in the entire area. This method for galvanic corrosion protection has defects such as uncontrolled glue coating amount or insufficient space for glue coating facilities. At the same time, the protection effect for galvanic corrosion also has certain limitations. Based on this, the present invention provides a galvanic corrosion protection method for the problem of galvanic corrosion formed when magnesium alloy structural parts contact with dissimilar metal connectors. First, the method provided by the present invention includes first performing a chemical conversion film treatment on the surface of the magnesium alloy structural part to form a chemical conversion film on the surface of the magnesium alloy structural part, and then performing a first coating anti-corrosion treatment on the dissimilar metal connector and the fastening assembly, so that a first anti-corrosion coating is formed on the surfaces of the dissimilar metal connector and the fastening assembly, respectively. Such a design can achieve physical isolation of all part substrates from the external environment, thereby achieving a better anti-galvanic corrosion effect. Furthermore, the present invention has found through research that, in the case where the fastening assembly is not subjected to coating anti-corrosion treatment, severe galvanic corrosion will occur between the dissimilar metal connectors and the magnesium alloy structural parts. Furthermore, if the dissimilar metal connectors and fastening connectors are subjected to chemical conversion film treatment in advance instead of the first coating anti-corrosion treatment, it will also cause the dissimilar metal connectors and fastening connectors to fail prematurely and contact with magnesium to form galvanic corrosion. The present invention chooses to first treat the surface of the magnesium alloy with a chemical conversion film and to perform the first coating anti-corrosion treatment on the dissimilar metal connectors and the fastening assembly, which effectively avoids galvanic corrosion between the bonding surfaces of the dissimilar metal connectors and the magnesium alloy structural parts. Secondly, the present invention can achieve quantitative positioning coating by applying structural adhesive to the contact bonding surfaces formed between the magnesium alloy structural parts treated with the chemical conversion film and the dissimilar metal connectors treated with the first coating anti-corrosion treatment, which can be fully controlled to enhance the anti-galvanic corrosion capability, and can further achieve physical isolation on the basis of ensuring the connection strength. Furthermore, the present invention locks the magnesium alloy structural part and the dissimilar metal connecting part whose contact surfaces are coated with structural adhesive by the fastening assembly to form an assembly, and then performs a second coating anti-corrosion treatment on the assembly. After the connection is completed, the locking integrated structure is subjected to an overall electrophoresis treatment, which can also have a certain degree of sealing effect on the connection surfaces of the components, further increasing the corrosion resistance of the entire magnesium-containing connection component structure.

[0057] In some embodiments of the present invention, in step one, the chemical conversion film treatment step includes: performing passivation treatment and sealing treatment on the magnesium alloy structural part.

[0058] In some embodiments of the present invention, the passivation treatment includes: performing activation pretreatment and phosphate passivation on the magnesium alloy structural member to form a fine granular phosphating film.

[0059] In some embodiments of the present invention, the sealing treatment comprises: filling and sealing the pores of the magnesium alloy structural member (1) to form a uniformly distributed organic sealing layer.

[0060] In the chemical conversion film treatment of the magnesium alloy structural parts, the present invention adds an inorganic sealing layer, which includes an inorganic pore-filling layer and a sealing layer. The inorganic pore-filling layer can increase the density of the chemical conversion film to enhance the corrosion resistance, and the sealing layer can increase the conductivity and the total film thickness of the protective layer to ensure 100% implementation of the electrophoresis process. In addition, by adopting this method, the contamination of magnesium ions in the pretreatment tank solution can be reduced, thereby increasing the versatility of the process implementation.

[0061] In some embodiments of the present invention, the chemical conversion film comprises: phosphates.

[0062] In some embodiments of the present invention, the thickness of the chemical conversion film is: <10um. Specifically, the thickness of the chemical conversion film can be: 0.1um, 0.5um, 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 9.5um, 9.9um or a range consisting of any two of the above values. Not limited to the listed values, other values ​​not listed in the numerical range are also applicable.

[0063] In some embodiments of the present invention, in step 2, the first coating anti-corrosion treatment includes at least one of black electrophoresis, zinc-aluminum coating, electroplating zinc, and electroplating zinc-nickel.

[0064] In some embodiments of the present invention, the thickness of the first anti-corrosion coating is 8-25um; specifically, the thickness of the first anti-corrosion coating can be 8um, 9um, 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23um, 24um, 25um or a range consisting of any two of the above values. Not limited to the listed values, other values ​​not listed in the numerical range are also applicable.

[0065] When the anti-corrosion treatment method of the first coating is black electrophoresis, the thickness of the first anti-corrosion coating is greater than 15um; when the anti-corrosion treatment method of the first coating is zinc-aluminum coating, the thickness of the first anti-corrosion coating is 8-25um; when the anti-corrosion treatment method of the first coating is electrogalvanizing, the thickness of the first anti-corrosion coating is 8-15um; when the anti-corrosion treatment method of the first coating is electrogalvanizing, the thickness of the first anti-corrosion coating is 8-15um.

[0066] In some embodiments of the present invention, when the first coating is treated with black electrophoresis for anti-corrosion, the components of the first anti-corrosion coating are resin and pigment; when the first coating is treated with zinc-aluminum coating for anti-corrosion, the components of the first anti-corrosion coating include: flaky zinc powder, flaky aluminum powder and inorganic binder; when the first coating is treated with zinc electroplating for anti-corrosion, the component of the first anti-corrosion coating is pure zinc; when the first coating is treated with zinc-nickel electroplating for anti-corrosion, the component of the first anti-corrosion coating is zinc-nickel alloy, wherein the weight proportion of nickel in the zinc-nickel alloy is 12-18%.

[0067] In some embodiments of the present invention, the dissimilar metal connector is a metal formed by any one of the metal elements of aluminum, zinc, iron, titanium, tin, lead, copper, silver, platinum and gold, or an alloy formed by any two or more of the metal elements of aluminum, zinc, iron, titanium, tin, lead, copper, silver, platinum and gold.

[0068] In some embodiments of the present invention, the structural adhesive is selected from epoxy resin. The structural adhesive is applied to the contact surfaces formed between the magnesium alloy structural parts and the dissimilar metal connectors, which can achieve quantitative positioning coating and be fully controlled, and can greatly improve the anti-galvanic corrosion capability.

[0069] In some embodiments of the present invention, the thickness of the structural adhesive is: <0.5mm. Specifically, the thickness of the structural adhesive is: 0.001mm, 0.005mm, 0.01mm, 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.45mm, 0.49mm or a range consisting of any two of the above values. Not limited to the listed values, other values ​​not listed in the numerical range are also applicable. Using structural adhesive of the above thickness can greatly reduce the risk of galvanic corrosion on the bonding surface.

[0070] In some embodiments of the present invention, in step four, the fastening connector includes a connecting fastener, a metal gasket and a non-metallic gasket, the outer diameter of the non-metallic gasket is larger than the outer diameter of the connecting fastener and the metal gasket, the metal gasket is arranged between the connecting fastener and the dissimilar metal connector, and the non-metallic gasket is arranged between the metal gasket and the dissimilar metal connector. Select a non-metallic gasket of suitable specifications so that the metal gasket and the dissimilar metal connector are not in direct contact, and finally ensure that the non-metallic gasket completely isolates the entire locking connection point from the external corrosive environment by setting a reasonable pre-tightening torque, so that galvanic corrosion cannot be formed. In the scheme provided by the present invention, non-metallic gaskets of various specifications can be provided to match the connecting fasteners and metal gaskets, and the purpose of pre-tightening can be easily achieved. Compared with the prior art that discloses the use of embedded threaded sleeves and non-metallic sheaths or the operation of applying glue after connection, the present invention sets a non-metallic gasket of suitable specifications to isolate the metal gasket from the dissimilar metal connector, which cannot form galvanic corrosion and also improves the installation efficiency.

[0071] In some embodiments of the present invention, the fastening connector is to subject the fastener and metal gasket to a first coating anti-corrosion treatment, and after forming a first anti-corrosion coating on the surface of the fastener and metal gasket, respectively, the fastening connector is assembled with the non-metallic gasket to form the fastening connector. The present invention has found through research that if dissimilar metal connectors, metal gaskets, etc. are not subjected to coating anti-corrosion treatment, dissimilar metal connectors and magnesium alloy structural parts will form severe galvanic corrosion, and the above-mentioned method of the present invention can effectively avoid galvanic corrosion of the contact and fitting surfaces of dissimilar metal connectors and magnesium alloy structural parts.

[0072] In some embodiments of the present invention, the fastening assembly is used to lock the magnesium alloy structural part and the dissimilar metal connecting part whose contact surfaces are coated with structural adhesive to form an assembly, which includes: according to a preset locking torque, the connecting fastener is sequentially passed through the metal gasket, the non-metallic gasket, the dissimilar metal connecting part and the magnesium alloy structural part for locking connection, and the fastening assembly and the dissimilar metal connecting part and the magnesium alloy structural part are locked as one, so as to obtain an assembly formed by the magnesium alloy structural part, the dissimilar metal connecting part and the fastening assembly.

[0073] In some embodiments of the present invention, the fastening assembly is locked against the magnesium alloy structural member and the dissimilar metal connector whose contact surfaces are coated with structural adhesive to form an assembly, which includes: according to a preset locking torque, the connecting fastener is sequentially passed through the metal gasket, the non-metallic gasket, the dissimilar metal connector, and the magnesium alloy structural member for locking connection, so as to obtain an assembly formed by the connecting fastener, the metal gasket, the non-metallic gasket, the magnesium alloy structural member, and the dissimilar metal connector. The above connection method can greatly reduce the risk of galvanic corrosion between the magnesium alloy structural member and the dissimilar metal connector. At the same time, the present invention provides a variety of non-metallic gaskets of various specifications to match the connecting fasteners and metal gaskets, which can easily achieve the purpose of pre-tightening. According to the connection method designed by this technical solution, the connection sequence of the magnesium alloy structural member and the dissimilar metal connector can be changed, so that the connection of the upper dissimilar metal connector and the lower magnesium alloy structural member or the upper magnesium alloy structural member and the lower dissimilar metal connector can be achieved, and the risk of galvanic corrosion can be avoided.

[0074] In some embodiments of the present invention, the second coating is treated for corrosion by electrophoresis.

[0075] In some embodiments of the present invention, the method of anti-corrosion treatment of the second coating includes pre-treating the assembly before performing the electrophoresis; the pre-treatment includes water washing and thin film process treatment.

[0076] According to a second aspect of the present invention, the present invention further provides a magnesium-containing connection component that is resistant to galvanic corrosion, the magnesium-containing connection component comprising:

[0077] A magnesium alloy structural part, the surface of which is coated with a chemical conversion film;

[0078] A dissimilar metal connector, the surface of which is coated with a first anti-corrosion coating;

[0079] Structural adhesive is coated on the contact bonding surface between the magnesium alloy structural part with the chemical conversion film on the surface and the dissimilar metal connecting part with the first anti-corrosion coating on the surface;

[0080] A fastening connector is used to connect the dissimilar metal connector and the magnesium alloy structural part, and the fastening assembly, the dissimilar metal connector and the magnesium alloy structural part are locked together to obtain the magnesium-containing connecting component, and the surface of the magnesium-containing connecting component is coated with a second anti-corrosion coating.

[0081] In some embodiments of the present invention, the fastening connector includes a connecting fastener, a metal gasket and a non-metallic gasket; in some embodiments of the present invention, the outer diameter of the non-metallic gasket is larger than the outer diameters of the connecting fastener and the metal gasket; the metal gasket is arranged between the connecting fastener and the heterogeneous metal connector, and the non-metallic gasket is arranged between the metal gasket and the heterogeneous metal connector.

[0082] In some embodiments of the present invention, the connecting fastener passes through the metal gasket, non-metallic gasket, dissimilar metal connecting piece and the magnesium alloy structural part in sequence to connect, and the fastening assembly and the dissimilar metal connecting piece and the magnesium alloy structural part are locked together to obtain the magnesium-containing connecting component.

[0083] In some embodiments of the present invention, the material of the non-metallic gasket is selected from at least one of polyurethane materials, epoxy resin materials and steel paper materials.

[0084] In some embodiments of the present invention, the chemical conversion film comprises: phosphate substances; the thickness of the chemical conversion film is: <10um. Specifically, the thickness of the chemical conversion film can be: 0.1um, 0.5um, 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 9.5um, 9.9um or a range consisting of any two of the above values. Not limited to the listed values, other values ​​not listed in the numerical range are also applicable.

[0085] In some embodiments of the present invention, the surfaces of the connecting fasteners and the metal gaskets are respectively coated with a first anti-corrosion coating.

[0086] In some embodiments of the present invention, the thickness of the first anti-corrosion coating is: 8-25um. Specifically, the thickness of the first anti-corrosion coating can be: 8um, 9um, 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um, 21um, 22um, 23um, 24um, 25um or a range consisting of any two of the above values. Not limited to the listed values, other unlisted values ​​within the numerical range are also applicable. When the first coating is treated by black electrophoresis for anti-corrosion, the thickness of the first anti-corrosion coating is greater than 15um; when the first coating is treated by zinc-aluminum coating for anti-corrosion, the thickness of the first anti-corrosion coating is 8-25um; when the first coating is treated by electrogalvanizing for anti-corrosion, the thickness of the first anti-corrosion coating is 8-15um; when the first coating is treated by electrogalvanizing for anti-corrosion, the thickness of the first anti-corrosion coating is 8-15um.

[0087] In some embodiments of the present invention, when the first coating is treated with black electrophoresis for anti-corrosion, the components of the first anti-corrosion coating are resin and pigment; when the first coating is treated with zinc-aluminum coating for anti-corrosion, the components of the first anti-corrosion coating include: flaky zinc powder, flaky aluminum powder and inorganic binder; when the first coating is treated with zinc electroplating for anti-corrosion, the component of the first anti-corrosion coating is pure zinc; when the first coating is treated with zinc-nickel electroplating for anti-corrosion, the component of the first anti-corrosion coating is zinc-nickel alloy, wherein the weight proportion of nickel in the zinc-nickel alloy is 12-18%.

[0088] In some embodiments of the present invention, the structural adhesive is selected from epoxy resins.

[0089] In some embodiments of the present invention, the thickness of the structural adhesive (6) is: <0.5 mm. Specifically, the thickness of the structural adhesive is: 0.001 mm, 0.005 mm, 0.01 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.45 mm, 0.49 mm or a range consisting of any two of the above values. Not limited to the listed values, other values ​​not listed in the numerical range are also applicable.

[0090] In some embodiments of the present invention, the components of the second anti-corrosion coating include: resin and pigment.

[0091] Hereinafter, the present invention will be described in more detail by using specific examples and comparative examples.

[0092] Example 1

[0093] This embodiment provides a method for optimizing galvanic corrosion between magnesium alloy and dissimilar metals. Figure 1 As shown, the details are as follows:

[0094] 1. Pretreatment of the magnesium alloy structural part 1 with a chemical conversion film; wherein the chemical conversion film pretreatment includes passivation and sealing, and the passivation is performed in a phosphate solution, and the specific steps of the passivation are: sequentially performing degreasing cleaning (40-60°C, 5-10min), pickling (room temperature, <2min), neutralization (40-80°C, <2min) and activation pretreatment (40-60°C, <2min) on the magnesium alloy structural part 1, and then performing phosphate passivation (room temperature, <2min); the sealing is an inorganic sealing, and the specific steps of the sealing are: sequentially completing hole filling (40-80°C, <5min) and sealing (40-60°C, <5min), and through the above steps, a chemical conversion film is formed on the surface of the magnesium alloy structural part 1. In this embodiment, the main component of the formed chemical conversion film is a phosphate substance, and the thickness of the formed chemical conversion film is 5um;

[0095] 2. The dissimilar metal connector 2, the connecting fastener 3 and the metal gasket 4 are respectively subjected to a coating anti-corrosion treatment; in this embodiment, the coating anti-corrosion treatment is performed by black electrophoresis, and through the above steps, an anti-corrosion coating is formed on the surface of the dissimilar metal connector 2, the connecting fastener 3 and the metal gasket 4, wherein the thickness of the formed anti-corrosion coating is 18 um;

[0096] 3. Select a non-metallic gasket 5 of corresponding specifications, and assemble it with the connecting fastener 3 and the metal gasket 4 after the coating anti-corrosion treatment in step 2 to form a fastening assembly. The outer diameter of the non-metallic gasket 5 needs to be larger than the outer diameters of the connecting fastener 3 and the metal gasket 4. Among them, the material of the non-metallic gasket 5 can be polyurethane or epoxy resin. In this embodiment, the non-metallic gasket 5 is selected from polyurethane;

[0097] Fourth, the contact and bonding surfaces of the magnesium alloy structural part 1 after the chemical conversion film pretreatment in step 1 and the dissimilar metal connecting part 2 after the coating anti-corrosion treatment in step 2 are coated with structural adhesive 6; wherein the structural adhesive 6 is epoxy resin structural adhesive, and the thickness of the structural adhesive 6 is 0.1 mm;

[0098] 5. According to the preset locking torque, the magnesium alloy structural member 1 coated with the structural adhesive 6 in step 4, the dissimilar metal connector 2 and the fastening assembly obtained in step 3 are assembled to achieve locking as one, that is, according to the preset locking torque, the magnesium alloy structural member 1 and the dissimilar metal connector 2 with the contact bonding surface coated with the structural adhesive 6 are assembled with the fastening assembly, the metal gasket 4 is arranged between the connecting fastener 3 and the dissimilar metal connector 2, the non-metallic gasket 5 is arranged between the metal gasket 4 and the dissimilar metal connector 2, the connecting fastener 3 passes through the metal gasket 4, the non-metallic gasket 5, the dissimilar metal connector 2 and the magnesium alloy structural member 1 in sequence to be connected, and the fastening assembly is locked as one with the dissimilar metal connector 2 and the magnesium alloy structural member 1 to obtain an assembly formed by the magnesium alloy structural member 1, the dissimilar metal connector 2 and the fastening assembly;

[0099] 6. The assembled parts formed by assembling magnesium alloy structural parts 1, dissimilar metal connectors 2, connecting fasteners 3, metal gaskets 4 and non-metallic gaskets 5 are subjected to coating anti-corrosion treatment; wherein, the coating anti-corrosion treatment method is electrophoresis, and its pre-treatment includes water washing and thin film process; wherein, the water washing process includes water washing and pure water washing, and the pure water washing mainly uses deionized water, and the conductivity is required to be ≤20μs / cm, and it is carried out by a combination of immersion and spraying; wherein, in the thin film process, the bath liquid pH is 4.0-5.5, the temperature is 25-40℃, the activation point is 6.0-10.0, the treatment time is 1.0-5.0min, and the film thickness is required to be 0.01-0.1um.

[0100] Example 2

[0101] This embodiment, based on Embodiment 1, provides a connection assembly structure that can improve galvanic corrosion caused by contact between magnesium alloy and dissimilar metals. The assembly structure includes:

[0102] A magnesium alloy structural part 1, wherein a chemical conversion film is coated on the surface of the magnesium alloy structural part 1, wherein the main component of the chemical conversion film is a phosphate substance and the thickness is 5 um;

[0103] A dissimilar metal connector 2, wherein the surface of the dissimilar metal connector 2 is coated with an anti-corrosion coating, and the thickness of the anti-corrosion coating is 18 um; the dissimilar metal connector 2 with the anti-corrosion coating on the surface is in contact with and bonded to a magnesium alloy structural member 1 with a chemical conversion film on the surface, and a structural adhesive 6 is coated on the contact and bonding surface between the dissimilar metal connector 2 and the magnesium alloy structural member 1, wherein the main component of the structural adhesive 6 is epoxy resin, and the thickness of the structural adhesive 6 is 0.1 mm;

[0104] The fastening assembly comprises a connecting fastener 3, a metal gasket 4 and a non-metal gasket 5, wherein the surfaces of the connecting fastener 3 and the metal gasket 4 are coated with an anti-corrosion coating; the non-metal gasket 5 is assembled with the connecting fastener 3 and the metal gasket 4 to form the fastening assembly, wherein the outer diameter of the non-metal gasket 5 is greater than the outer diameter of the connecting fastener 3 and the metal gasket 4, and the non-metal gasket 5 is selected from polyurethane;

[0105] According to the preset locking torque, the magnesium alloy structural member 1 and the dissimilar metal connector 2 with the contact bonding surface coated with structural adhesive 6 are assembled with the fastening assembly, the metal gasket 4 is arranged between the connecting fastener 3 and the dissimilar metal connector 2, the non-metallic gasket 5 is arranged between the metal gasket 4 and the dissimilar metal connector 2, the connecting fastener 3 passes through the metal gasket 4, the non-metallic gasket 5, the dissimilar metal connector 2 and the magnesium alloy structural member 1 in sequence, and the fastening assembly and the dissimilar metal connector 2 and the magnesium alloy structural member 1 are locked as a whole to obtain an assembly formed by the magnesium alloy structural member 1, the dissimilar metal connector 2 and the fastening assembly; the surface of the formed assembly is coated with an anti-corrosion coating.

[0106] Comparative Example 1

[0107] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloy and dissimilar metals. The difference from Example 1 is that the magnesium alloy structural part 1 is directly coated with glue in the entire area, that is, the step of first subjecting the magnesium alloy structural part 1 to chemical conversion film treatment and then coating the structural glue 6 on the contact bonding surface between the magnesium alloy structural part 1 and the dissimilar metal connecting part 2 in Example 1 is not performed. The specific details are as follows:

[0108] 1. Apply glue to the entire area of ​​the magnesium alloy structural member 1 to form an anti-corrosion coating;

[0109] 2. Same as Example 1;

[0110] 3. Same as Example 1;

[0111] Fourth, the difference from Example 1 is that in this comparative example, the structural adhesive 6 is not applied on the contact and bonding surfaces between the magnesium alloy structural member 1 and the dissimilar metal connecting member 2;

[0112] 5. Same as Example 1;

[0113] 6. Same as Example 1.

[0114] Comparative Example 2

[0115] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloy and dissimilar metals. The difference from Example 1 is that in step 1, only the magnesium alloy structural part 1 is passivated without inorganic sealing treatment. The rest is the same as Example 1, specifically as follows:

[0116] 1. performing chemical conversion film pretreatment on the magnesium alloy structural part 1; wherein the chemical conversion film pretreatment is only a passivation treatment;

[0117] 2. Same as Example 1;

[0118] 3. Same as Example 1;

[0119] 4. Same as Example 1;

[0120] 5. Same as Example 1;

[0121] 6. Same as Example 1.

[0122] Comparative Example 3

[0123] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloy and dissimilar metals. The difference from Example 1 is that in step 2, the dissimilar metal connector 2 is not subjected to a coating anti-corrosion treatment, which is as follows:

[0124] 1. Same as Example 1;

[0125] Second, only the connecting fastener 3 and the metal gasket 4 are subjected to the coating anti-corrosion treatment, and the rest is the same as in Example 1;

[0126] 3. Same as Example 1;

[0127] 4. Same as Example 1;

[0128] 5. Same as Example 1;

[0129] 6. Same as Example 1.

[0130] Comparative Example 4

[0131] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloys and dissimilar metals. The difference from Example 1 is that the structure of the fastening assembly is different. The fastening assembly in Comparative Example 1 does not include a metal gasket 4, but only includes a connecting fastener 3 and a non-metallic gasket 5. That is, when forming an assembly, the connecting fastener 3 passes through the non-metallic gasket 5, the dissimilar metal connector 2 and the magnesium alloy structural part 1 in sequence to be connected, and the fastening assembly, the dissimilar metal connector 2 and the magnesium alloy structural part 1 are locked as a whole to obtain an assembly formed by the magnesium alloy structural part 1, the dissimilar metal connector 2 and the fastening assembly. The rest is the same as Example 1.

[0132] Comparative Example 5

[0133] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloys and dissimilar metals. The difference from Example 1 is that the structure of the fastening assembly is different. The fastening assembly in Comparative Example 1 does not include a non-metallic gasket 5, but only includes a connecting fastener 3 and a metal gasket 4. That is, when forming an assembly, the connecting fastener 3 passes through the metal gasket 4, the dissimilar metal connector 2 and the magnesium alloy structural part 1 in sequence to be connected, and the fastening assembly and the dissimilar metal connector 2 and the magnesium alloy structural part 1 are locked as a whole to obtain an assembly formed by the magnesium alloy structural part 1, the dissimilar metal connector 2 and the fastening assembly. The rest is the same as Example 1.

[0134] Comparative Example 6

[0135] This comparative example is based on Example 1 and provides a method for galvanic corrosion protection of magnesium alloy and dissimilar metals. The difference from Example 1 is that step 6 is removed, that is, the assembly formed by assembling the magnesium alloy structural part 1, the dissimilar metal connecting part 2, the connecting fastener 3, the metal gasket 4 and the non-metallic gasket 5 is not subjected to coating anti-corrosion treatment, which is as follows:

[0136] 1. Same as Example 1;

[0137] 2. Same as Example 1;

[0138] 3. Same as Example 1;

[0139] 4. Same as Example 1;

[0140] 5. As in Example 1, an assembly formed by the magnesium alloy structural member 1, the dissimilar metal connecting member 2 and the fastening assembly is obtained.

[0141] Effect example

[0142] Based on the connection component structure for protecting the magnesium alloy from galvanic corrosion when in contact with a dissimilar metal formed by the methods of the above-mentioned Example 1 / Example 2 and Comparative Examples 1-7, the corrosion resistance of the corresponding protection method or the connection component structure for protecting the magnesium alloy from galvanic corrosion when in contact with a dissimilar metal formed by the methods of the above-mentioned Example 1 / Example 2 and Comparative Examples 1-7 is further verified by a 6-week cyclic corrosion verification test, as follows:

[0143] The anti-corrosion ability of the above groups was verified through the "6-week cyclic corrosion verification test". The anti-corrosion ability verification results obtained through the above verification method are shown in Table 1:

[0144] Table 1

[0145]

[0146]

[0147] The corrosion resistance comparison results shown in Table 1 indicate that the galvanic corrosion protection method for magnesium alloys and dissimilar metals according to the embodiments of the present invention or the structure of the connection assembly that improves the galvanic corrosion caused by the contact between magnesium alloys and dissimilar metals can significantly optimize the galvanic corrosion caused by the contact between magnesium alloys and dissimilar metals, and has an excellent corrosion resistance effect.

[0148] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are within the scope of protection of the present invention.

Claims

1. A galvanic corrosion protection method, characterized in that: Applied to galvanic corrosion caused by contact between magnesium alloy structural parts and dissimilar metal connecting parts, the galvanic corrosion protection method includes:

1. performing a chemical conversion film treatment on the magnesium alloy structural part (1) to form a chemical conversion film on the surface of the magnesium alloy structural part (1); 2. performing a first coating anti-corrosion treatment on the dissimilar metal connector (2) and the fastening assembly, and forming a first anti-corrosion coating on the surfaces of the dissimilar metal connector (2) and the fastening assembly respectively; 3. coating a structural adhesive (6) on the contact bonding surface formed between the magnesium alloy structural part (1) treated with the chemical conversion film and the dissimilar metal connecting part (2) treated with the first coating for corrosion protection; Fourth, the fastening assembly is used to lock the magnesium alloy structural part (1) and the dissimilar metal connecting part (2) whose contact surfaces are coated with structural adhesive (6) to form an assembly part, and the assembly part is subjected to a second coating anti-corrosion treatment to form a second anti-corrosion coating on the surface of the assembly part.

2. The galvanic corrosion protection method according to claim 1, characterized in that: In step 1, the chemical conversion film treatment process includes: The magnesium alloy structural part (1) is subjected to passivation treatment and sealing treatment; the passivation treatment comprises: performing activation pretreatment and phosphate passivation on the magnesium alloy structural part (1) to form a fine granular phosphate film; The sealing treatment comprises: filling and sealing the pores of the magnesium alloy structural part (1) to form a uniformly distributed organic sealing layer.

3. The galvanic corrosion protection method according to claim 1, characterized in that: In step 2, the first coating anti-corrosion treatment method includes at least one of black electrophoresis, zinc-aluminum coating, electroplating zinc and electroplating zinc-nickel.

4. The galvanic corrosion protection method according to claim 1, characterized in that: In step 4, the fastening connector includes a connecting fastener (3), a metal gasket (4) and a non-metallic gasket (5), wherein the outer diameter of the non-metallic gasket (5) is greater than the outer diameters of the connecting fastener (3) and the metal gasket (4); the metal gasket (4) is arranged between the connecting fastener (3) and the dissimilar metal connector (2), and the non-metallic gasket (5) is arranged between the metal gasket (4) and the dissimilar metal connector (2).

5. The galvanic corrosion protection method according to claim 4, characterized in that: The fastening connector is obtained by subjecting the fastening connector (3) and the metal gasket (4) to a first coating anti-corrosion treatment. After the first anti-corrosion coating is formed on the surface of the fastening connector (3) and the metal gasket (4), the fastening connector is assembled with the non-metallic gasket (5) to form the fastening connector.

6. The galvanic corrosion protection method according to claim 1, characterized in that: In step 4, the fastening assembly is locked against the magnesium alloy structural part (1) and the dissimilar metal connecting part (2) whose contact surfaces are coated with structural adhesive (6) to form an assembly part, which includes: according to a preset locking torque, the connecting fastener (3) is sequentially passed through the metal gasket (4), the non-metallic gasket (5), and the dissimilar metal connecting part (2) and the magnesium alloy structural part (1) for locking connection, thereby obtaining an assembly part formed by the connecting fastener (3), the metal gasket (4), the non-metallic gasket (5), the magnesium alloy structural part (1), and the dissimilar metal connecting part (2).

7. The galvanic corrosion protection method according to claim 1, characterized in that: The second coating anti-corrosion treatment method includes electrophoresis; Before the electrophoresis is performed, the method further includes: pre-processing the assembly; the pre-processing includes water washing and thin film process treatment.

8. A magnesium-containing connection assembly resistant to galvanic corrosion, characterized in that: The magnesium-containing connection assembly comprises: A magnesium alloy structural part (1), wherein the surface of the magnesium alloy structural part (1) is coated with a chemical conversion film; A dissimilar metal connector (2), wherein the surface of the dissimilar metal connector (2) is coated with a first anti-corrosion coating; A structural adhesive (6) is coated on the contact bonding surface between the magnesium alloy structural part (1) whose surface is coated with a chemical conversion film and the dissimilar metal connecting part (2) whose surface is coated with a first anti-corrosion coating; A fastening connector, the surface of which is coated with a first anti-corrosion coating, through which a dissimilar metal connector (2) is connected to a magnesium alloy structural part (1), and the fastening assembly, the dissimilar metal connector (2) and the magnesium alloy structural part (1) are locked together to obtain the magnesium-containing connection component, the surface of which is coated with a second anti-corrosion coating.

9. The magnesium-containing connection assembly according to claim 8, characterized in that: The fastening connector comprises a connecting fastener (3), a metal gasket (4) and a non-metal gasket (5); the outer diameter of the non-metal gasket (5) is greater than the outer diameters of the connecting fastener (3) and the metal gasket (4); the metal gasket (4) is arranged between the connecting fastener (3) and the heterogeneous metal connecting piece (2), and the non-metal gasket (5) is arranged between the metal gasket (4) and the heterogeneous metal connecting piece (2).

10. The magnesium-containing connection assembly according to claim 9, characterized in that: The connecting fastener (3) passes through the metal gasket (4) and the non-metal gasket (5) in sequence to connect with the dissimilar metal connecting piece (2) and the magnesium alloy structural piece (1), and the fastening assembly is locked together with the dissimilar metal connecting piece (2) and the magnesium alloy structural piece (1) to obtain the magnesium-containing connecting assembly; The surfaces of the connecting fastener (3) and the metal gasket (4) are respectively coated with a first anti-corrosion coating.

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