CN115325853A

CN115325853A - Heat exchanger and method for manufacturing the same

Info

Publication number: CN115325853A
Application number: CN202210768185.5A
Authority: CN
Inventors: 余书睿; 左玉克; 唐建华; 刘玉章; 黄海
Original assignee: Hangzhou Lvneng New Energy Auto Parts Co ltd; Hangzhou Sanhua Research Institute Co Ltd
Current assignee: Hangzhou Lvneng New Energy Auto Parts Co ltd; Hangzhou Sanhua Research Institute Co Ltd
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2022-11-11
Anticipated expiration: 2042-07-01
Also published as: CN115325853B

Abstract

The application provides a heat exchanger, including base member and hydrophilic coating, the base member includes first base member and second base member, and at least one in first base member and the second base member has the recess, and partly intussuseption is filled with adhesive or solder, and the adhesive or the solder of filling in the recess all contact with first base member and second base member, and at least part coating is located the recess. The first base member of heat exchanger that this application provided is connected reliably between second base member, and the coating firmly combines with the base member. The present application also provides a method of manufacturing a heat exchanger, comprising: providing a first substrate and a second substrate, wherein at least one of the first substrate and the second substrate is provided with a groove, connecting the first substrate and the second substrate, enabling an adhesive or a welding flux filled in the groove to be in contact with both the first substrate and the second substrate, covering a hydrophilic coating, and at least partially arranging the coating in the groove. The manufacturing method can manufacture the heat exchanger with the first substrate and the second substrate which are reliably connected and the coating and the heat exchanger substrate are firmly combined.

Description

Heat exchanger and method for manufacturing the same

Technical Field

The application relates to the technical field of heat exchange, in particular to a heat exchanger and a manufacturing method thereof.

Background

In heat exchangers, the connections between the components may be made using adhesives or solder. For example, to achieve a connection between the two components, an adhesive or solder may be provided on the outer surface of one of the two components, which are then assembled. However, because the outer surface of the component is smooth, less adhesive and less solder remains on the surface of the component, making a reliable connection between the two components difficult to achieve.

In addition, there is a need for heat exchangers that increase surface drainage to improve anti-frost properties.

Accordingly, there is a need for improvement of the related art, improvement of connection reliability between components in a heat exchanger, and increase of surface drainage of the heat exchanger.

Disclosure of Invention

In order to solve the technical problem, the application provides a heat exchanger which is reliable in connection between components and good in surface drainage performance, and the application further provides a manufacturing method of the heat exchanger.

A first aspect of the application provides a heat exchanger, which comprises a substrate and a coating, wherein the coating is covered on at least part of the surface of the substrate;

the substrate comprises a first substrate and a second substrate, at least one of the first substrate and the second substrate is provided with a groove, and the groove is formed by inwards sinking from the outer surface of at least one of the first substrate and the second substrate;

the grooves comprise a first groove and a second groove, the first groove is filled with adhesive or solder, the adhesive or the solder filled in the first groove is contacted with both the first base body and the second base body, the coating is covered on the outer surface of at least one of the first base body and the second base body, and at least part of the coating is positioned in the second groove;

the coating comprises micro-nano particles, and the micro-nano particles comprise hydrophilic modified silicon dioxide and/or titanium dioxide.

In this application, at least one of the first and second substrates has a groove, including a first groove and a second groove. The first groove is filled with adhesive or solder, and the adhesive or solder filled in the first groove is contacted with the first base body and the second base body. The first groove can accommodate more adhesive or welding flux for connecting the first base body and the second base body, so that the connection between the first base body and the second base body is more reliable. The coating is at least partially positioned in the second groove, so that the bonding force of the coating and the heat exchanger substrate can be increased. In addition, the coating of the present application includes hydrophilic modified silica and/or titania, which can improve the surface drainage performance of the heat exchanger.

A second aspect of the present application provides a manufacturing method of a heat exchanger, the manufacturing method including the steps of:

providing a first substrate and a second substrate, at least one of the first substrate and the second substrate having a groove formed recessed inward from an outer surface of at least one of the first substrate and the second substrate, the groove comprising a first groove and a second groove;

connecting the first substrate and the second substrate so that the first groove is filled with adhesive or solder, and the adhesive or the solder filled in the first groove is in contact with both the first substrate and the second substrate;

providing a coating on at least a portion of an outer surface of at least one of the first substrate and the second substrate, the coating comprising a hydrophilic coating such that at least a portion of the hydrophilic coating is located within the second groove.

The manufacturing method provided by the application is characterized in that at least one of the first base body and the second base body is provided with a groove, and the groove comprises a first groove and a second groove. When the first base body and the second base body are connected, the first groove can accommodate more adhesive or welding flux for connecting the first base body and the second base body, so that the connection between the first base body and the second base body is more reliable. When the coating is coated, the coating is at least partially positioned in the second groove, so that the bonding force between the coating and the heat exchanger substrate can be increased. In addition, the coating provided by the manufacturing method of the application comprises hydrophilic modified silicon dioxide and/or titanium dioxide, and the surface drainage performance of the heat exchanger can be improved. Therefore, the manufacturing method provided by the application can manufacture the heat exchanger which is reliable in connection between the first substrate and the second substrate, firmly combined with the substrate and good in surface drainage performance.

Drawings

FIG. 1 is a schematic view of a heat exchanger provided in accordance with an embodiment of the present application;

FIG. 2 is a schematic illustration of a connection between a first substrate and a second substrate provided in accordance with an embodiment of the present application;

FIG. 3 is a schematic view of another angled connection of a first substrate and a second substrate provided in accordance with an embodiment of the present application;

FIG. 4 is a schematic view of a connection between a first substrate and a second substrate provided in one embodiment of the related art;

FIG. 5 is an enlarged schematic view of portion a of FIG. 3 according to an embodiment of the present application;

FIG. 6 is an enlarged schematic view of portion a of FIG. 3 according to another embodiment of the present application;

FIG. 7 is a schematic view of a first substrate provided in accordance with an embodiment of the present application;

FIG. 8 is a schematic view of a second substrate provided in accordance with an embodiment of the present application;

FIG. 9 is a flow chart of a method of manufacturing a heat exchanger provided by one embodiment of the present application;

FIG. 10 is a flow chart of step S1 of a method of manufacturing a heat exchanger according to an embodiment of the present application;

FIG. 11 is a flow chart illustrating a step S2 of a method for manufacturing a heat exchanger according to an embodiment of the present application;

FIG. 12 is a flow chart of step S2 of a method of manufacturing a heat exchanger according to another embodiment of the present application;

FIG. 13 is a flow chart illustrating step S3 of a method for manufacturing a heat exchanger according to an embodiment of the present application;

fig. 14 is a scanning electron microscope image of a first substrate provided in one embodiment of the present disclosure after grit blasting.

Detailed Description

For better understanding of the technical solutions of the present application, the following detailed descriptions of the embodiments of the present application are provided with reference to the accompanying drawings.

It should be understood that the embodiments described are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In heat exchangers, the connections between the components may be made using adhesives or solder. For example, to achieve a connection between the two components, an adhesive or solder may be provided on the outer surface of one of the two components, which are then assembled. However, because the outer surfaces of the components are smooth, less adhesive and less solder remains on the surfaces of the components, making a reliable connection between the two components difficult to achieve. In addition, since the outer surface of the member is smooth, it is difficult for the coating to be firmly bonded to the outer surface of the member.

To this end, the present application provides a heat exchanger, such as shown in fig. 1, 3,5, and 6, including a base including a first base 11 and a second base 12, at least one of the first base 11 and the second base 12 having a groove 3 formed by recessing inward from an outer surface of at least one of the first base 11 and the second base 12. The grooves comprise a first groove 31 and a second groove 32, the first groove 31 is filled with adhesive or solder, the adhesive or solder filled in the first groove 31 is in contact with both the first base body 11 and the second base body 12, the coating 2 covers the outer surface of at least one of the first base body 11 and the second base body 12, and at least part of the coating 2 is positioned in the second groove 32.

In the present application, at least one of the first base and the second base has a groove including a first groove and a second groove. The first groove is filled with adhesive or solder, and the adhesive or solder filled in the first groove is contacted with the first base body and the second base body. The first groove can accommodate more adhesive or welding flux for connecting the first base body and the second base body, so that the connection between the first base body and the second base body is more reliable. The coating is at least partially positioned in the second groove, so that the bonding force of the coating and the heat exchanger substrate can be increased.

In some embodiments, the substrate includes a third substrate 13, and the adhesive or solder filled in the first recess 31 is in contact with the third substrate. That is, the adhesive or solder filled in the first groove 31 is in contact with each of the first substrate 11, the second substrate 12, and the third substrate 13, thereby achieving the connection of the first substrate 11, the second substrate 12, and the third substrate 13.

Illustratively, as shown in fig. 1, a heat exchanger 100 includes a plurality of heat exchange tubes 101, a plurality of fins 102, and two headers 103, such as shown in fig. 1. The heat exchange tube 101 is fixedly connected with the collecting pipe 103, the heat exchange tube 101 is hermetically connected with the collecting pipe 103, and the inner cavity of the heat exchange tube 101 is communicated with the inner cavity of the collecting pipe 103. A plurality of heat exchange tubes 101 are arranged along the length direction of the header 103. The thickness direction of the heat exchange tube 101 is parallel to the length direction of the header 103, and the width direction of the heat exchange tube 101 is perpendicular to the length direction of the header 103. The thickness direction of the heat exchange tube 101 may refer to an X direction in fig. 1 and 2, the width direction of the heat exchange tube 101 may refer to a Y direction in fig. 2, and the length direction of the heat exchange tube 101 may refer to a Z direction in fig. 1 and 2. Wherein, the X direction, the Y direction and the Z direction are mutually vertical. The fin 102 is located between two adjacent heat exchange tubes 101, and the fin 102 is fixedly connected with the two adjacent heat exchange tubes 101. The fins 102 are corrugated along the length of the heat exchange tube 101. The arrangement of the fins 102 can increase the heat exchange area of two adjacent heat exchange tubes 101, and improve the heat exchange efficiency of the heat exchanger 100. In some embodiments, a window structure may be disposed in a partial region of the fin 102 to form a louver-type fin, so as to further enhance heat exchange.

In some embodiments, a heat exchange tube 101 is provided with a plurality of independent channels (microchannels) arranged in parallel inside, as shown in fig. 3, and the heat exchanger thus formed is a microchannel heat exchanger. In some embodiments, the heat exchange tubes 101, fins 102, and headers 103 in a microchannel heat exchanger are all made of a material comprising aluminum/aluminum alloy.

In order to achieve the connection between the heat exchange pipe 101, the fin 102 and the current collecting pipe 103, a solder may be provided on the outer surfaces of the fin 102 and the current collecting pipe 103. After the heat exchange tube 101, the fin 102 and the current collecting tube 103 are arranged, the whole assembly is heated to a temperature higher than the melting point of the solder to melt the solder, and then cooled to solidify the solder, thereby realizing the fixed connection among the heat exchange tube 101, the fin 102 and the current collecting tube 103 through the solder. Because the surfaces of the heat exchange tube 101, the fin 102 and the collecting tube 103 are smooth, only a small amount of solder can be left between the heat exchange tube 101 and the fin 102 and between the heat exchange tube 101 and the collecting tube 103 for welding, as shown in fig. 4, the connection reliability between the heat exchange tube 101, the fin 102 and the collecting tube 103 is poor.

In addition, in order to improve the surface drainage performance of the heat exchanger, a corresponding hydrophilic coating can be arranged on the surface of the heat exchanger. In the related art, since the surfaces of the heat exchange pipe 101, the fins 102, and the current collecting pipe 103 are smooth, it is difficult to firmly bond with the coating.

In some embodiments, as shown in FIG. 1, heat exchanger 100 comprises a substrate and a coating 2, coating 2 being applied to at least a portion of a surface of the substrate. The base body includes first base body 11, second base body 12 and third base body 13, and first base body 11 is heat exchange tube 101, and second base body 12 is fin 102, and third base body 13 is pressure manifold 103. At least one of the first substrate 11, the second substrate 12 and the third substrate 13 has a groove 3. That is, the groove 3 may be provided only on one of the first substrate 11, the second substrate 12, and the third substrate 13, may be provided on any two of the first substrate 11, the second substrate 12, and the third substrate 13, or may be provided on all of the first substrate 11, the second substrate 12, and the third substrate 13. The grooves 3 include a first groove 31 and a second groove 32. The groove 3 is a groove in which at least one of the first substrate 11, the second substrate 12, and the third substrate 13 is recessed inward from the outer surface. For example, the groove 3 provided in the first base 11 is a groove recessed inward from the outer surface of the first base 11, as shown in fig. 5 and 6, for example.

The first groove 31 is filled with adhesive or solder 4, and the adhesive or solder 4 filled in the first groove 31 is in contact with at least two of the first base 11, the second base 12 and the third base 13. That is, the adhesive or solder 4 filled in the first groove 31 may be used to connect any two of the first substrate 11, the second substrate 12, and the third substrate 13, or may be used to connect the first substrate 11, the second substrate 12, and the third substrate 13. For example, if the adhesive or solder 4 filled in the first groove 31 is in contact with the first substrate 11 and the second substrate 12, the adhesive or solder 4 filled in the first groove 31 can achieve the connection of the first substrate 11 and the second substrate 12, as shown in fig. 5. If the adhesive or solder filled in the first groove 31 is in contact with all of the first substrate 11, the second substrate 12, and the third substrate 13, the adhesive or solder filled in the first groove 31 can achieve the connection of the first substrate 11, the second substrate 12, and the third substrate 13. The adhesive or solder filled in the first groove 31 may be completely located in the first groove 31, as shown in fig. 6, for example, or the adhesive or solder filled in the first groove 31 may be partially located in the first groove 31 and partially overflow the first groove 31, as shown in fig. 5, for example.

In this manner, the first groove 31 can accommodate more adhesive or solder for connecting at least two of the first substrate 11, the second substrate 12, and the third substrate 13, so that the connection between at least two of the first substrate 11, the second substrate 12, and the third substrate 13, that is, the connection between at least two of the heat exchange tube 101, the fin 102, and the header 103, is more reliable.

The coating 2 is coated on the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13, and at least part of the coating 2 is positioned in the second groove 32, as shown in fig. 5. The roughness of the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13 is increased through the second groove 32, so that the bonding force between the coating 2 and the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13 can be improved, and the coating 2 and the heat exchanger substrate are firmly bonded.

In some embodiments, the first substrate 11 has a first recess 31 and a second recess 32. The adhesive or solder filled in the first groove 31 is in contact with the first base 11, and the adhesive or solder filled in the first groove 31 is in contact with at least one of the second base 12 and the third base 13, as shown in fig. 5. In this way, the first recess 31 can accommodate more adhesive or solder for connecting the first substrate 11 with the second substrate 12, or for connecting the first substrate 11 with the third substrate 13, or for connecting the first substrate 11 with the second substrate 12 and the third substrate 13. The second grooves 32 formed in the first substrate 12 can enhance the roughness of the outer surface of the first substrate 11, so that the coating 2 can be firmly bonded to the outer surface of the first substrate 11, that is, the coating 2 can be firmly bonded to the heat exchange pipe 101.

Specifically, for example, as shown in fig. 3 and 5 to 7, the outer surface of the first substrate 11 includes a first surface 111 and a second surface 112. The first surface 111 and the second surface 112 intersect each other, and the contour line of the first surface 111 is at least partially the intersection line of the first surface 111 and the second surface 112. The first substrate 11 is connected with at least one of the second substrate 12 and the third substrate 13 through the first surface 111, at least part of the second surface 112 is coated with the coating 2, the first substrate 11 is recessed inwards from the first surface 111 to form a first groove 31, and the first substrate 11 is recessed inwards from the second surface 112 to form a second groove 32.

When the first substrate 11 is attached to the second substrate 12 through the first face 111, the adhesive or solder 4 filled in the first groove 31 is in contact with the first face 111, and the adhesive or solder filled in the first groove 31 is in contact with the second substrate 12, as shown in fig. 5. In this way, the first recess 111 can accommodate more adhesive or solder 4 for a reliable connection of the first face 111 to the second base body 12, i.e. of the first base body 11 to the second base body 12.

When the first base 11 is connected to the third base 13 through the first face 111, the adhesive or solder filled in the first groove 31 is in contact with the first face 111, and the adhesive or solder filled in the first groove 31 is in contact with the third base 13. In this way, the first groove 111 can accommodate more adhesive or solder for achieving a reliable connection of the first face 111 with the third base 13, that is, the first base 11 with the third base 13.

At least a portion of the second surface 112 is coated with the coating 2, as shown in fig. 5, the second groove 32 disposed on the first substrate 11 can increase the roughness of the second surface 112, so that the coating 2 can be firmly combined with the second surface 112, that is, the coating 2 can be firmly combined with the first substrate 11 or the heat exchange tube 101.

In some embodiments, one first substrate 11 has at least two first surfaces 111, and at least a portion of the second surface 112 is located between two adjacent first surfaces 111 of the same first substrate 11, as shown in fig. 7. In some embodiments, the first substrate 11 is connected to said second substrate 12 through at least one of said first faces 111, and the first substrate 11 is connected to said third substrate through at least one of said first faces 111.

Specifically, in some embodiments, as shown in fig. 7, the first surface 111 includes a first sub-surface 1111 and a second sub-surface 1112, the first substrate 11 is connected to the second substrate 12 through the first sub-surface 1111, and the first substrate 11 is connected to the third substrate 13 through the second sub-surface 1112. The first groove 31 includes a first sub-groove (not shown) and a second sub-groove (not shown). The first sub-groove is a groove recessed from the first sub-surface 1111 into the first substrate 11, and the second sub-groove is a groove recessed from the first sub-surface 1112 into the first substrate 11. The first sub-groove is filled with adhesive or solder, the adhesive or solder filled in the first sub-groove is in contact with the first sub-surface 1111, and the adhesive or solder filled in the first sub-groove is in contact with the second substrate 12. In this way, reliable connection of the first substrate 11 and the second substrate 12 can be achieved. The second sub-groove is filled with adhesive or solder, the adhesive or solder filled in the second sub-groove is in contact with the second sub-surface 1112, and the adhesive or solder filled in the second sub-groove is in contact with the third substrate 13. In this way, reliable connection of the first substrate 11 and the third substrate 13 can be achieved.

In some embodiments, one first substrate 11 has at least two first sub-surfaces 1111, and at least a portion of the second substrate 112 is located between two adjacent first sub-surfaces 1111 of the same first substrate 11, as shown in fig. 7. In this way, one first substrate 11 is connected to the second substrate 12 through at least two first sub-surfaces 1111, which increases the reliability of the connection between the first substrate 11 and the second substrate. In some embodiments, at least two first sub-faces 1111 are aligned along a length direction (refer to a Z direction shown in fig. 1 and 2) of the heat exchange tube. As shown in fig. 3 and 7, the first substrate 11 has a flat shape, the first substrate 11 has a side wall 110, the side wall 110 is perpendicular to a thickness direction of the heat exchange tube 101, a plurality of first sub-surfaces 1111 are provided to an outer surface of the side wall 110, and the plurality of first sub-surfaces 1111 are arranged in a length direction (Z direction) of the heat exchange tube, a part of the second surface 112 is provided to the outer surface of the side wall 110, and a part of the second surface 112 is located between the adjacent two first sub-surfaces 1111. The second surface 112 is connected with the first sub-surface 1111, and the connection line of the second surface 112 and the first sub-surface 1111 is the contour line of the first sub-surface 1111.

In some embodiments, first grooves 31 make first side 111 a rough side, and second grooves 32 make second side 112 a rough side. In some embodiments, the roughness of each of the first and

second faces

111, 112 is 0.5 μm to 10 μm. In some embodiments, the roughness of the first and

second faces

111, 112 is formed by grit blasting.

In other embodiments, second substrate 12 has a first recess 31 and a second recess 32. The adhesive or solder filled in the first groove 31 is in contact with the second substrate 12, and the adhesive or solder filled in the first groove 31 is in contact with at least one of the first substrate 11 and the third substrate 13. In this manner, the first recess 31 can accommodate more adhesive or solder for connecting the second substrate 12 with the first substrate 11, and/or the second substrate 12 with the third substrate 13. The second grooves 32 formed in the second substrate 12 can enhance the roughness of the outer surface of the second substrate 12, so that the coating 2 can be firmly bonded to the outer surface of the second substrate 12, that is, the coating 2 can be firmly bonded to the fins 102.

In some embodiments, the outer surface of the second substrate 12 includes a third surface 121 and a fourth surface 122, the third surface 121 and the fourth surface 122 meet, and the contour of the third surface 121 is at least partially the meeting line of the third surface 121 and the fourth surface 122, as shown in fig. 8. The second substrate 12 is connected to at least one of the first substrate 11 and the third substrate 13 through a third surface 121, at least a portion of a fourth surface 122 is coated with the coating 2, the second substrate 12 is recessed inward from the third surface 121 to form a first groove 31, and the second substrate 12 is recessed inward from the fourth surface 122 to form a second groove 32.

In other embodiments, the third substrate 13 has a first recess 31 and a second recess 32. The adhesive or solder filled in the first groove 31 is in contact with the third base 13, and the adhesive or solder filled in the first groove 31 is in contact with at least one of the first base 11 and the second base 12. In this manner, the first recess 31 can accommodate more adhesive or solder for connecting the third substrate 13 with the first substrate 11, and/or the third substrate 13 with the second substrate 12. The second grooves 32 formed in the third substrate 13 can enhance the roughness of the outer surface of the third substrate 13, so that the coating 2 can be firmly bonded to the outer surface of the third substrate 13, that is, the coating 2 can be firmly bonded to the header 103.

In some embodiments, the outer surface of the third substrate 13 includes a fifth surface (not shown) and a sixth surface (not shown), the fifth surface and the sixth surface being joined, and the contour line of the fifth surface being at least partially the joining line of the fifth surface and the sixth surface. The third substrate 13 is connected to at least one of the first substrate 11 and the third substrate 13 through a fifth surface, at least a portion of the sixth surface is covered with the coating 2, the third substrate 13 is recessed from the fifth surface to form a first groove 31, and the third substrate 13 is recessed from the sixth surface to form a second groove 32.

The coating of the heat exchanger surface can be set according to the actual need. For example, in order to improve the drainage effect of the heat exchanger surface, a hydrophilic coating may be provided on the heat exchanger surface. Due to the special application environment and application conditions of the heat exchanger, for example, the temperature change amplitude of the surface of the heat exchanger is large in the heat exchange process, and the like, the composite material provided by the related art is difficult to form a proper coating on the surface of the heat exchanger. The hydrophilic coating formed by coating the composite material in the related art on the surface of the heat exchanger may be easily peeled off from the surface of the heat exchanger, or the coating may cause a decrease in the heat exchange efficiency of the heat exchanger. Still other coatings do not meet the requirements of green and environmental protection due to the pungent smell generated during the preparation process. Thus, the present application also provides coatings suitable for use in heat exchangers.

In some embodiments, the coating 2 comprises micro-nano particles comprising at least one of hydrophilically modified silica and titanium dioxide. The hydrophilically modified silica refers to silica modified by a hydrophilic group. The titanium dioxide particles have an amphoteric nature as well as photocatalytic properties, which are photo-induced superhydrophilic. The silicon dioxide particles and the titanium dioxide particles are favorable for forming a complex micro-nano structure. In some embodiments, the titanium dioxide is titanium dioxide modified by a hydrophilic group. The hydrophilic coating 2 is made of at least one of the hydrophilic modified silica and the titanium dioxide, and the hydrophilic coating 2 can make the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13 have a good drainage effect, so that the frosting is delayed.

In some embodiments, the micro-nano particle comprises hydrophilic modified silica and titanium dioxide, wherein the content of the hydrophilic modified silica is higher than the content of the titanium dioxide. The hydrophilic coating can form a structure with stable physical performance and chemical performance by simultaneously containing the hydrophilic modified silicon dioxide and the titanium dioxide, so that the hydrophilic coating is stable and compact, the hydrophilicity of the coating can be further improved, and the effects of good hydrophilicity and durability and corrosion resistance are achieved.

In some embodiments, the hydrophilic coating 2 further comprises a hydrophilic resin, i.e. the hydrophilic coating 2 comprises micro-nano particles and a hydrophilic resin. The leveling property and the stability of the hydrophilic resin are beneficial to maintaining the micro-nano structure for a long time, and the high molecular chemical structure of the hydrophilic resin is matched with the hydrophilic modified silicon dioxide particles and the titanium dioxide particles, so that the compactness of the coating and the number of hydrophilic groups can be improved, and the hydrophilic durability of the coating can be enhanced.

In some embodiments, the hydrophilic resin comprises at least one of an acrylic resin, an amino resin, a polyurethane resin, an alkyd resin, or an epoxy resin; the weight per unit area of the hydrophilic coating 2 was 9g/m ² ～14g/m ² . In some embodiments, in the hydrophilic coating 2, the sum of the mass percentages of the hydrophilic modified silica and the titanium dioxide is larger than the mass percentage of the hydrophilic resin.

In other embodiments, the hydrophilic resin is a polymer obtained by polymerizing a monomer, and the monomer corresponding to the polymer includes a hydrophilic group-containing acryl-based monomer. The polymer in the present application is formed by polymerizing at least one monomer, which is a generic name for small molecules polymerizable with the same kind or other molecules, and is a simple compound capable of forming a high molecular compound by a polymerization reaction, a polycondensation reaction, or the like, and is a low molecular material used for synthesizing the polymer. The above-mentioned monomer may be a monomer including a double bond or a triple bond, and this type of monomer may be polymerized with other monomers through its double bond or triple bond. After the polymer is formed, the hydrophilic group of the monomer can be complemented with the hydrophilic group of the modified micro-nano particles, so that the hydrophilicity of the final coating is improved. The hydrophilic group contained in the monomer can be hydroxyl (-OH), aldehyde (-CHO), carboxyl (-COOH), amino (-NH) ₂ ) Sulfonic acid group (-SO) ₃ H) Hydrophilic groups such as phosphate groups, sulfate groups, amide groups, and quaternary ammonium groups.

In some embodiments, the acrylic monomer is an unsaturated double bond-containing monomer, for example, hydroxyethyl methacrylate, methacrylic acid, methyl methacrylate, methyl acrylate, butyl acrylate, hydroxypropyl acrylate, methacrylamide, acrylamide, N-methacrylamide; the weight per unit area of the hydrophilic coating 2 was 15g/m ² ～20g/m ² . The polymer herein may be formed by polymerization between one monomer or polymerization of different monomer phases, and the polymerization process may serve to initiate polymerization between the monomers by adding an initiator.

In some embodiments of the present application, the polymer is predominantly polyhydroxyethyl methacrylate formed by polymerizing hydroxyethyl methacrylate monomers. It is noted that hydroxyethyl methacrylate may also be included in the coating if the hydroxyethyl methacrylate monomer is not sufficiently polymerized.

In some embodiments, the hydrophilic coating 2 further comprises at least one of polyvinyl alcohol and polyethylene glycol. The polyvinyl alcohol and/or the polyethylene glycol are beneficial to improving the strength and the durability of the film layer.

In order to form the coating layer on the surface of the substrate of the heat exchanger, the corresponding coating material can be prepared, coated on the surface of the heat exchanger by dip coating, spray coating, brush coating, curtain coating or roller coating, and cured. As described above, since the surfaces of the heat exchange tube, the header and the fin are smooth, it is difficult for the coating to firmly adhere to the surfaces of the heat exchange tube, the header and the fin base. In order to enable the coating to be firmly attached to the surface of the heat exchanger base body, the surface to be coated may be sandblasted before the corresponding coating is applied. The sand blasting treatment can increase the surface roughness, and further increase the bonding force between the coating and the surface.

Specifically, after the heat exchanger is assembled, the heat exchanger may be subjected to sand blasting, and then the composite material is sprayed on the surface of the heat exchanger and cured to form the coating layer 2. However, because the assembled components of the heat exchanger are shielded from each other during the sandblasting process, a portion of the outer surface of the heat exchanger cannot be in contact with the sandblasting. For example, in the microchannel heat exchanger 100 shown in fig. 1, the fin 102 is located between two adjacent heat exchange tubes 101, and the gap between the fin 102 and the heat exchange tube 101 adjacent to the fin is small. During the sand blasting, it is difficult for the abrasive to reach a portion of the outer surface of the heat exchange pipe 101, resulting in difficulty in achieving a desired roughness for the portion of the outer surface of the heat exchange pipe 101 by the sand blasting. In addition, in the sand blasting process, due to the high stacking density of the fins 102, the abrasive is easily clamped between the fins 102 or between the fins 102 and the heat exchange tube 101, and is difficult to remove. Moreover, the sand blasting treatment of the assembled heat exchanger may damage the heat exchanger, for example, in the sand blasting process, the abrasive ejected at high speed generates impact force on the joint of the heat exchange pipe and the collecting pipe and the joint of the heat exchange pipe and the fin, which causes connection failure and even leakage of the heat exchange pipe.

To this end, the present application provides a method of manufacturing a heat exchanger, as shown in fig. 9, the method comprising the steps of:

s1, providing a first substrate 11 and a second substrate 12, wherein at least one of the first substrate 11 and the second substrate 12 is provided with a groove 3, the groove 3 is a groove inwards recessed from the outer surface of at least one of the first substrate 11 and the second substrate 12, and the groove 3 comprises a first groove 31 and a second groove 32.

And S2, connecting the first base body 11 with the second base body 12, so that the first groove 31 is filled with adhesive or solder, and the adhesive or solder filled in the first groove 31 is contacted with both the first base body 11 and the second base body 12.

S3, coating 2 is coated on the outer surface of at least one of the first substrate 11 and the second substrate 12, so that at least part of the coating 2 is located in the second groove 32, the coating 2 comprises micro-nano particles, and the micro-nano particles comprise hydrophilic modified silicon dioxide and/or titanium dioxide.

It will be appreciated that in the present application, the steps of providing the first substrate 11 and the second substrate 12 are also performed before the step S2 of joining the first substrate 11 and the second substrate 12 and before the step S3 of applying the coating. That is, the first substrate 11 and the second substrate 12 are first provided, and then the steps of attaching and coating are performed. Therefore, in the present application, step S1 precedes steps S2 and S3. However, the present application does not limit the order of step S2 and step S3, and step S2 may be before step S3 or after step S3.

In some embodiments, the heat exchanger 100 further comprises a third base 13, in particular the method of manufacturing the heat exchanger further comprises the steps of:

s1', providing a third substrate 13;

s2', the first substrate 11, the second substrate 12, and the third substrate 13 are connected such that the adhesive or the solder filled in the first groove 31 is in contact with each of the first substrate 11, the second substrate 12, and the third substrate 13.

Illustratively, in some embodiments, a method of manufacturing a heat exchanger includes the steps of:

the method comprises the following steps of S1, providing a first base body 11, a second base body 12 and a third base body 13, wherein the first base body 11 is used for forming a heat exchange tube 101, the second base body 12 is used for forming a fin 102, the third base body 13 is used for forming a collecting pipe 103, at least one of the first base body 11, the second base body 12 and the third base body 13 is provided with a groove 3, the groove 3 is a groove which is inwards recessed from the outer surface of at least one of the first base body 11, the second base body 12 and the third base body 13, and the groove 3 comprises a first groove 31 and a second groove 32.

And S2, connecting the first base body 11, the second base body 12 and the third base body 13, so that the first groove 31 is filled with adhesive or solder, and the adhesive or solder filled in the first groove 31 is in contact with at least two of the first base body 11, the second base body 12 and the third base body 13.

And S3, coating 2 is coated on the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13, so that at least part of the coating 2 is positioned in the second groove 32.

In the manufacturing method provided by the present application, since the groove 3 is provided on at least one of the first substrate 11, the second substrate 12, and the third substrate 13, the groove 3 includes the first groove 31 and the second groove 32. When the first base 11, the second base 12, and the third base 13 are connected, the first groove 31 can accommodate more adhesive or solder for connecting at least two of the first base 11, the second base 12, and the third base 13, so that the connection between at least two of the first base 11, the second base 12, and the third base 13, that is, the connection between at least two of the header 103, the heat exchange tube 101, and the fin 102, is more reliable. When the coating is applied, the coating 2 is at least partially located within the second recess 32, and the second recess 32 is capable of increasing the bonding force of the coating 2 to at least one of the first substrate 11, the second substrate 12, and the third substrate 13. Therefore, according to the manufacturing method provided by the present application, a heat exchanger in which the connection between the heat exchange tube 101, the fin 102, and the header pipe 103 is reliable and the coating 2 is firmly bonded to the heat exchanger base body can be manufactured.

In some embodiments, the grooves 3 are formed by grit blasting. That is, the present application first prepares the first substrate 11 and the second substrate 12 having grooves on the surfaces thereof through a sand blasting process, and then performs a step of connecting the first substrate 11 and the second substrate 12, and a step of coating at least one of the first substrate 11 and the second substrate 12 with a coating layer.

In some embodiments, as shown in fig. 10, step S1 of providing the first substrate 11 and the second substrate 12 comprises the following steps:

s11, providing base materials, wherein the base materials comprise a first base material for forming a first base body 11 and a second base material for forming a second base body 12;

and S12, performing sand blasting treatment on the outer surface of at least one of the first base material and the second base material.

In some embodiments, at least one of the first substrate and the second substrate has a size larger than the corresponding base, and therefore, the step S1 of providing the first base 11 and the second base 12 further includes the following steps:

and S13, cutting at least one of the first base material and the second base material, as shown in figure 10.

The benefits of grit blasting include, in the first aspect, the removal of residual oxide, oil, etc., from the surface of the substrate, resulting in a cleaner metal substrate surface. And in the second aspect, a better micro rough surface structure is formed on the surface of the base material under the sand blasting and polishing effects of the abrasive, so that the bonding force between the base material and other coating materials is increased, and the leveling and decoration of the coating are facilitated. In a third aspect, the cutting and impacting of the sandblasting strengthens the mechanical properties of the surface of the metal base material, improving the fatigue resistance of the metal base material. In the fourth aspect, the sand blasting can remove irregular structures such as burrs on the surface of the metal base material, and a small fillet is made on the surface of the metal base material, so that the surface of the metal base material is more smooth and attractive, and the subsequent treatment is facilitated. After sand blasting treatment, the surface tissue form of the metal base material is changed, and metal grains are more refined and compact. After the sand blasting treatment, more hydroxyl groups are formed on the surface of the metal base material, and in the process of connecting the subsequent functional film layer, the hydroxyl groups of the functional film layer and the hydroxyl groups of the metal base material are subjected to dehydration condensation, so that the functional film layer and the metal base material can be connected through covalent bonds, and the covalent bonds are relatively stable in connection mode, thereby being beneficial to improving the durability of the connection with the functional film layer.

In addition, the treatment mode of the sand blasting process has the characteristics of high efficiency, low cost and suitability for large-surface-area cleaning treatment of the metal base material, and furthermore, the grinding material adopted by the sand blasting process can be recycled, so that the cost can be further reduced.

Next, step S1 will be described by taking a microchannel heat exchanger as an example.

In some embodiments, step S1 of providing the first substrate 11, the second substrate 12, and the third substrate 13 comprises the steps of:

s11, providing base materials, wherein the base materials comprise a first base material for forming a first base body 11, a second base material for forming a second base body 12 and a third base material for forming a third base body 13;

and S12, performing sand blasting treatment on the outer surface of at least one of the first base material, the second base material and the third base material.

In some embodiments, the first substrate has the same length, thickness and width as the first substrate 11, and the first substrate 11 can be obtained by performing sand blasting. In some embodiments, the second substrate has the same thickness, width, and length as the second substrate 12, and the second substrate is subjected to sand blasting to obtain the second substrate 12. In some embodiments, the third substrate has the same length, outer diameter, and inner diameter as the third substrate 13, and the third substrate is sandblasted to obtain the third substrate 13.

In other embodiments, the length of the first substrate is greater than the length of the first base 11, the length of the second substrate is greater than the length of the second base 12, and the length of the third substrate is greater than the length of the third base 13, and the first base, the second base, and the third base are obtained by cutting the first substrate, the second substrate, and the third substrate.

In some embodiments, step S1 of providing the first substrate 11, the second substrate 12 and the third substrate 13 further comprises the steps of:

and S13, cutting at least one of the first base material, the second base material and the third base material.

As such, the first base material is made to have the same size (e.g., length, width, and thickness) as the first base 11, the second base material is made to have the same size (e.g., length, width, and thickness) as the second base 12, and the third base material is made to have the same size (e.g., length, outer diameter, and inner diameter) as the third base 13.

In some embodiments, the first base material has the same thickness and width as the first base 11, and has the same internal structure as the first base 11, except that the first base material has a length greater than the first base 11, and all structural parameters of the first base material are the same as the first base 11 (as shown in fig. 7), and providing the first base 11 further comprises: the first base material is cut such that the length of the first base material is the same as the length of the first base 11. The thickness direction of the first base material refers to the X direction shown in fig. 1 and 2, and the width direction of the first base material refers to the Y direction in fig. 2.

In some embodiments, the first substrate has an inner cavity and an opening, the inner cavity of the first substrate is communicated with the outside of the first substrate through the opening, the inner cavity of the first substrate is used for forming an inner cavity of the heat exchange tube 101 for flowing a cooling liquid or a cooling medium, and the inner cavity of the first substrate comprises a plurality of channels, and the plurality of channels can be used for forming a plurality of micro channels of the heat exchange tube 101. In some embodiments, the opening of the first substrate is plugged prior to grit blasting the outer surface of the first substrate. In this manner, the ingress of abrasive for blasting into the internal cavity of the first substrate through the opening can be reduced.

In some embodiments, the second substrate has the same thickness and width as second base 12, all of the structural parameters of the second substrate are the same as second base 12 (as shown in fig. 8) except that the length of the second substrate is greater than second base 12, and providing second base 12 further comprises: the second base material 12 is cut so that the length of the second base material is the same as the length of the second base body 12. The thickness direction of the second base material refers to the X direction shown in fig. 1 and 2, and the width direction of the second base material refers to the Y direction in fig. 2.

In some embodiments, the third substrate has an outer diameter and an inner diameter that are both the same as the third base 13, and the third substrate has an internal structure that is the same as the third base 13, all structural parameters of the third substrate are the same as the third base 13 except that the third substrate has a length that is greater than the third base 13, providing the third base 13 further comprises: the third base material is cut so that the length of the third base material is the same as the length of the third base 13.

In some embodiments, the third substrate has an inner cavity and an opening, the inner cavity of the third substrate is communicated with the outside of the third substrate through the opening, and the inner cavity of the third substrate is used for forming an inner cavity of the collecting pipe 103 for flowing the cooling liquid or the cooling medium. In some embodiments, the openings of the third substrate are plugged prior to grit blasting the outer surface of the third substrate. In this manner, the ingress of abrasive for blasting into the internal cavity of the third substrate through the opening can be reduced.

The step of cutting the first substrate, the second substrate, and the third substrate may be performed before or after the blasting. Taking the example of processing the first base material into the first base body 11, the thickness and the width of the first base material are the same as those of the first base body 11, and the outer surface of the first base material may be subjected to sand blasting firstly, and then the sand blasted first base material may be cut according to the length of the first base body 11 to obtain the first base body 11; alternatively, the first base material subjected to the sandblasting process is cut according to the length of the first base body, and then the first base material after the cutting is subjected to the sandblasting process, so that the first base body 11 is obtained.

In some embodiments, step S12 of sandblasting an outer surface of at least one of the first substrate, the second substrate, and the third substrate includes: the abrasive is mixed in compressed air and sprayed by a spray gun toward an outer surface of at least one of the first base material, the second base material, and the third base material. Furthermore, the abrasive can be corundum-based gravel, such as brown corundum, white corundum, black corundum, garnet, and the like. The abrasive can also be a grit of the silicon carbide type, such as black silicon carbide, green silicon carbide, and the like. Of course, when the abrasive is selected, other kinds of gravels can be selected, and the abrasive can be glass beads, steel shots, steel grit, ceramic grit, resin grit, walnut grit and the like.

In some embodiments, the abrasive has a particle size between 30 mesh and 280 mesh. Specifically, the particle size of the abrasive may be 30 mesh, 50 mesh, 80 mesh, 120 mesh, 150 mesh, 180 mesh, 200 mesh, 220 mesh, 250 mesh, 280 mesh, or the like. The grain size of abrasive selects the construction that can influence metal substrate surface mat surface, and when the grain size mesh of abrasive was great relatively, metal substrate's surface mat surface can be more meticulous, and when the grain size mesh was too big, the roughness of mat surface can be difficult to guarantee. When the particle size is too small, the formation of a rough surface having a certain roughness is relatively slow, and the roughening effect is poor. In some embodiments, the abrasive can have a particle size ranging between 100 mesh to 200 mesh. Therefore, the grain diameter of the grinding material is not too large or too small, and accordingly, a more ideal rough surface structure is more easily obtained.

In some embodiments, the distance between the spray gun and the respective spray location of the outer surface of at least one of the first substrate, the second substrate, and the third substrate is between 20mm and 100 mm. Specifically, the distance between the nozzle of the spray gun and the corresponding spraying position of the outer surface of the heat exchanger is simply recorded as the sand blasting distance, the sand blasting distance is too close, pits are easily formed in the surface of the metal base material, the overall rough surface is poor in appearance, the sand blasting distance is too far, the impact force of abrasive materials is poor, and the surface form degree of the metal base material is poor. The blasting distance may be selected in this application to be 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm, 100mm, etc. In some embodiments, the blasting distance may be between 50mm and 100 mm.

In some embodiments, the spray angle α of the spray gun satisfies 0 < α ≦ 90. The ejection angle of the spray gun refers to an angle between the incident direction of the abrasive and a plane in which the outer surface of at least one of the first base material, the second base material, and the third base material is located, and specifically, the ejection angle α of the spray gun is 15 °, 30 °, 45 °, 60 °, 75 °, 90 °, and so on. The spray angle α of the spray gun is too small, the interference angle between the metal base material and the abrasive is small, and it is difficult to form a rough surface, and the spray angle α of the spray gun may be an acute angle of 90 ° or less. In some embodiments of the present application, the spray angle α of the spray gun is 45 °.

In some embodiments, the pressure of the compressed air is 0.45MPa to 0.65MPa, specifically, the pressure of the compressed air is 0.45MPa, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa. Because each part collecting pipe, fin and heat exchange tube of the heat exchanger are mostly made of aluminum materials in the industry, and correspondingly, the aluminum materials are relatively soft, the pressure of compressed air cannot be too high, otherwise, the parts are easily damaged. Of course, the pressure of the compressed air must not be too low, otherwise it is difficult to form a rough surface. In some embodiments of the present application, the pressure of the compressed air is 0.45MPa.

In some embodiments, an outer surface of at least one of the first substrate, the second substrate, and the third substrate may be grit blasted using a grit blaster.

In some embodiments, as shown in fig. 13, the outer surface of at least one of the first substrate 11 and the second substrate 12 is provided with solder, and step S2, connecting the first substrate 11 and the second substrate 12, includes the steps of:

s21, assembling the first substrate 11 and the second substrate 12;

s22, heating the first substrate 11 and the second substrate 12 to melt the solder;

and S23, cooling the first substrate 11 and the second substrate 12 to solidify the solder.

In other embodiments, as shown in fig. 14, step S2, i.e., connecting the first substrate 11 and the second substrate 12, comprises the steps of:

s21', covering an adhesive on at least one of the first base body 11 and the second base body 12;

s22', assembling the first substrate 11 and the second substrate 12;

s23', and curing the adhesive.

Assembling the first base 11 and the second base 12 means that the first base 11 and the second base 12 are placed in accordance with their positions in the heat exchanger 100.

Step S2 will be described below by taking the microchannel heat exchanger described above as an example. In some embodiments, in step S2, the first substrate 11, the second substrate 12, and the third substrate 13 are connected by an adhesive or solder. For the connection of the first substrate 11 and the second substrate 12, the first substrate 11 may be connected to the second substrate 12 by solder or adhesive. For example, all of the first substrates 11 may be connected to the second substrate 12 by solder, or all of the first substrates 11 may be connected to the second substrate by adhesive, or a part of the first substrates 11 may be connected to the second substrate 12 by solder and another part of the first substrates 11 may be connected to the second substrate 12 by adhesive, or several of the plurality of first substrates 11 may be connected to the second substrate 12 by solder and the other several of the plurality of first substrates 11 may be connected to the second substrate 12 by adhesive. Likewise, the connection of the first substrate 11 to the third substrate 13, and the connection of the second substrate 12 to the third substrate 13, may be performed in various ways.

In some embodiments, at least one of the first substrate 11, the second substrate 12 and the third substrate 13 is covered with solder, and the step S2 of connecting the first substrate 11, the second substrate 12 and the third substrate 13 includes:

s21, assembling the first substrate 11, the second substrate 12 and the third substrate 13;

s22, heating the first substrate 11, the second substrate 12 and the third substrate 13 to melt the solder;

and S23, cooling the first substrate 11, the second substrate 12 and the third substrate 13 to solidify the solder.

For example, when the first substrate 11, the second substrate 12, and the third substrate 13 are connected, first, solder is applied to the second substrate 12 and the third substrate 13, and the recess 3 is provided in the first substrate 11. Then, the first substrate 11, the second substrate 12, and the third substrate 13 are assembled, and thereafter, the first substrate 11, the second substrate 12, and the third substrate 13 are placed in a heating furnace and heated, so that the solder is melted and filled in the first grooves 31 provided in the first substrate 11. The solder filled in the first groove 31 recessed from the first sub-surface 111 toward the inside of the first base 11 is in contact with the first base 11 and the second base 12, and this portion of the solder is used to achieve the connection of the first base 11 and the second base 12. The solder filled in the first groove 31 recessed from the second sub-surface 112 toward the inside of the first base 11 contacts the first base 11 and the third base 13, and this portion of the solder is used to realize the connection of the first base 11 and the third base 13. In the present application, the first surface 111, the second surface 112, the first sub-surface 1111, and the second sub-surface 1112 are not regions divided in advance before the first base 11, the second base 12, and the third base 13 are assembled, but regions defined according to the relative positional relationship between the first base 11 and the second base 12, and the relative positional relationship between the first base 11 and the third base 13 after the first base 11, the second base 12, and the third base 13 are assembled. For example, the area where the outer surface of the sidewall 110 of the first substrate 11 is connected to the second substrate 12 is defined as a first sub-surface 1111, and the area where the outer surface of the sidewall 110 of the first substrate 11 is connected to the third substrate 13 is defined as a second sub-surface 1112.

The solder may be melted by putting the first substrate 11, the second substrate 12, and the third substrate 13 into a heating furnace after they are integrally assembled. In the present application, the grooves formed on the outer surface of at least one of the first substrate 11, the second substrate 12, and the third substrate 13 by the sand blast processing are not affected at a high temperature in a temperature range where the solder is melted, or in a temperature range where the furnace is passed, that is, the roughness of the outer surface of the first substrate 11, the second substrate 12, and the third substrate 13 on which the grooves are formed is substantially maintained before and after the furnace is passed.

In other embodiments, step S2, i.e., connecting the first substrate 11, the second substrate 12, and the third substrate 13, includes:

s21', covering an adhesive on at least one of the first base body 11, the second base body 12 and the third base body 13;

s22', assembling the first substrate 11, the second substrate 12 and the third substrate 13;

s23', and curing the adhesive.

For example, when the first substrate 11, the second substrate 12, and the third substrate 13 are connected, first, an adhesive is applied to the second substrate 12 and the third substrate 13, and the first substrate 11 is provided with the recess 3. Then, the first substrate 11, the second substrate 12, and the third substrate 13 are assembled, and at least a part of the adhesive provided on the second substrate 12 and the third substrate 13 is caused to flow into the first groove 31 provided on the first substrate 11 before the adhesive is cured. The adhesive filled in the first groove 31 recessed from the first sub-surface 111 toward the inside of the first base 11 is in contact with the first base 11 and the second base 12, and this portion of the adhesive is used to achieve the connection between the first base 11 and the second base 12. The adhesive filled in the first groove 31 recessed from the second sub-surface 112 toward the inside of the first base 11 is in contact with the first base 11 and the third base 13, and this portion of the adhesive is used to connect the first base 11 and the third base 13. The way of curing the adhesive varies according to the kind of the adhesive, for example, some adhesives may be cured by natural air drying.

In some embodiments, as shown in fig. 13, step S3 of providing a coating 2 on an outer surface of at least one of the first substrate 11 and the second substrate 12 comprises the steps of:

s31, providing a composite material for forming the coating 2, wherein the composite material comprises micro-nano particles, and the micro-nano particles comprise at least one of hydrophilic modified silicon dioxide and titanium dioxide;

and S32, coating the composite material on at least part of the outer surface of at least one of the first substrate 11 and the second substrate 12, and curing to form the coating 2.

Step S3 will be described below by taking the microchannel heat exchanger described above as an example. In some embodiments, step S3 of providing a coating 2 on an outer surface of at least one of the first substrate 11, the second substrate 12, and the third substrate 13 comprises the steps of:

s31, providing a composite material for forming the coating 2;

and S32, coating the composite material on at least part of the outer surface of at least one of the first substrate 11, the second substrate 12 and the third substrate 13, and curing to form a hydrophilic coating.

In some embodiments of the present application, the composite material provided in step S31 is used to form a hydrophilic coating.

In some embodiments, the composite material includes a hydrophilic mixed sol including 90 to 92 parts of a hydrophilic modified silica sol and 4 to 6 parts of a titania sol, and the step S31 of providing the composite material for forming the coating layer 2 includes the steps of:

s311, providing the hydrophilic mixed sol.

Specifically, the preparation method of the hydrophilic hybrid sol in step S311 includes: mixing 90-92 parts by mass of hydrophilic modified silica sol and 4-6 parts by mass of titanium dioxide sol to obtain a mixed solution, adjusting the pH value of the mixed solution to 2.5-3.5 by adopting 3-5 parts by mass of a pH value regulator, and stirring and reacting at 45-55 ℃ for 3.5-5 h to obtain the hydrophilic mixed sol.

In order to further optimize the amount of each component in the hydrophilic mixed sol and promote the synergistic cooperation effect of the components, in some embodiments, the hydrophilic mixed sol comprises the following raw materials in parts by mass: 91 parts of hydrophilic modified silica sol, 5 parts of titanium dioxide sol and 4 parts of pH value regulator.

The hydrophilic mixed sol is mainly prepared from appropriate and proper hydrophilic modified silica sol, titanium dioxide sol and a pH regulator, and the hydrophilic mixed sol with excellent hydrophilic performance is obtained. The hydrophilic modified silica sol and the titanium dioxide sol are hydrophilic materials, have certain reactive groups or hydrophilic groups, such as hydroxyl (-OH), can obtain a compact coating through the mutual reaction among particles, and can exert the basic performances of stable chemical performance, weather resistance, hydrophilicity and the like of the coating.

In some embodiments, from 90 to 92 parts of the hydrophilic modified silica sol, 34 to 36 parts of the hydrophilic modified silica sol is prepared by the preparation method provided in the examples of the present application, and the rest of the hydrophilic modified silica sol is commercially available. Further, in some embodiments, the hydrophilic mixed sol comprises the following raw materials in parts by mass: 35 parts of self-made hydrophilic modified silica sol, 56 parts of commercially available hydrophilic modified silica sol, 5 parts of titanium dioxide sol and 4 parts of pH value regulator.

The embodiment of the present invention has no limitation on the sources and specific types of the raw materials such as the titanium dioxide sol, the pH adjuster, etc., and those skilled in the art can flexibly select the raw materials according to actual needs as long as the purpose of the present invention is not limited. As the starting materials, those known to those skilled in the art can be used, and commercially available products thereof can be used, or they can be prepared by themselves by a preparation method known to those skilled in the art.

In some embodiments, the at least partially hydrophilically modified silica sol can be prepared by: according to the mass portion, 36-40 portions of silane precursor and 50-56 portions of solvent are uniformly mixed at 45-55 ℃, then 2-4 portions of water and 0.5-1.5 portions of surfactant are added and uniformly mixed, then 1-2 portions of acid and 2-4 portions of water are added and reacted for 22-24 h, and the hydrophilic modified silica sol is obtained.

In some embodiments, the silane precursor comprises 30 to 32 parts of gamma-glycidoxypropyltrimethoxysilane (abbreviated as KH-560) and 6 to 8 parts of ethyl orthosilicate. In some embodiments, the solvent comprises an alcoholic solvent, and the alcoholic solvent comprises an alcoholic solvent having 1 to 10 carbon atoms, preferably an alcoholic solvent having 1 to 8 carbon atoms, and more preferably an alcoholic solvent having 1 to 4 carbon atoms. Further, in some embodiments, the solvent is any one of methanol, ethanol, and isopropanol or a mixture of any two or more of them in any ratio. In some embodiments, the surfactant comprises at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and hexadecyl benzene sulfonic acid; the acid includes, but is not limited to, at least one of formic acid, acetic acid.

In some specific embodiments, the method for preparing the home-made hydrophilic modified silica sol comprises the following steps:

according to the mass parts, 31 parts of KH-560, 7 parts of ethyl orthosilicate and 54 parts of absolute ethyl alcohol are mechanically stirred and uniformly mixed under the condition of 50 ℃ water bath to obtain a solution A; then adding 3 parts of water and 1 part of sodium dodecyl sulfate into the solution A after uniformly mixing; then adding 1 part of formic acid and 3 parts of water into the solution A, uniformly mixing, and keeping the reaction conditions unchanged for about 24 hours to obtain the hydrophilic modified silica sol.

The equations or reaction mechanisms involved in the preparation of the silica sol described above can be as follows:

1) Hydrolysis and condensation of tetraethoxysilane: si (OCH) ₂ CH ₃ ) ₄ +2H ₂ O→SiO ₂ +4C ₂ H ₅ OH。

2) KH560 hydrolyzes R-Si (OCH) ₃ ) ₃ +3H ₂ O→R-Si(OH) ₃ +CH ₃ OH

KH560 polycondensation of R-Si (OH) ₃ +R-Si(OH) ₃ →R-Si(OH) ₂ -O-Si(OH) ₂ -R+H ₂ O

R-Si(OH) ₃ +R-Si(OCH3) ₃ →R-Si(OH) ₂ -O-Si(OH) ₂ -R+CH ₃ OH

Wherein R represents a long chain group- (CH) in KH560 ₂ ) ₃ -O-CH ₂ -CH-OCH ₂ KH560 has the following structural formula (I):

3) Condensation of KH560 with silicon hydroxyl groups: R-Si (OH) ₃ +Si(OH) ₄ →R-Si(OH) ₂ -O-Si(OH) ₃ +H ₂ O。

The silica sol prepared by the embodiment of the application contains a large number of hydroxyl (-OH) hydrophilic groups, so that the sol shows hydrophilicity, and a space network structure is formed by dehydration condensation between the hydroxyl groups. Therefore, the nano particles such as silicon dioxide and titanium dioxide which are further added into the hydrophilic coating and dispersed are filled into the space network structure, a stable sol system, namely the hydrophilic coating, can be formed, the sol of the hydrophilic coating can be combined with-OH in a metal substrate, a covalent bond is formed by dehydration and condensation, and the effect of protecting the metal substrate is achieved after film forming, so that the hydrophilic and corrosion-resistant effects are achieved.

In some embodiments, the composite material includes 10 to 30 parts by mass of a hydrophilic resin and 70 to 90 parts by mass of a hydrophilic hybrid sol, and the step S31 of providing the composite material for forming the coating layer 2 further includes the steps of:

s312, providing a hydrophilic resin, wherein the hydrophilic resin comprises at least one of acrylic resin, amino resin, polyurethane resin, alkyd resin or epoxy resin.

S313, mixing 10-30 parts of hydrophilic resin with 70-90 parts of hydrophilic mixed sol.

The kind and some properties of the hydrophilic resin have been described above and will not be described herein. In some embodiments, the hydrophilic resin is an acrylic resin. A commercially available acrylic resin may be used, or an acrylic resin may be obtained by a homemade process.

In some embodiments, the hydrophilic resin in step S312 comprises an acrylic resin, and at least a portion of the acrylic resin may be prepared by: mixing 0.5-1 parts by mass of a first part of initiator with 45-55 parts by mass of propylene glycol monomethyl ether acetate preheated to 90-110 ℃ to obtain a mixed solution B; mixing 30-35 parts of first monomer, 15-20 parts of second monomer and 0.2-0.4 part of second part of initiator to obtain mixed solution C; and dropwise adding the mixed solution C into the mixed solution B, after dropwise adding is finished, adding 0.1-0.3 part of a third part of initiator into a reaction system, and carrying out heat preservation reaction at the temperature of 90-110 ℃ for 0.5-2 h to obtain the acrylic resin. Wherein the first portion of initiator, the second portion of initiator, and the third portion of initiator may be the same type of initiator or may also be different types of initiators, in some embodiments the same type of initiator. The first, second and third portions of initiator differ primarily in the amounts of initiator added.

In some embodiments, the initiator includes, but is not limited to, at least one of t-butyl hydroperoxide, azobisisobutyronitrile, dibenzoyl peroxide, t-amyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide, 3,3-ethyl bis (t-butylperoxy) butyrate, 3,3-ethyl bis (t-amylperoxy) butyrate, t-butyl peroxybenzoate, t-amyl peroxyacetate, 1,1' -bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, t-butyl 2-ethylhexyl peroxide, and t-amyl 2-ethylhexyl peroxide.

In some embodiments, the first and second monomers are each independently selected from at least one of acrylic acid, hydroxyethyl methacrylate, methacrylic acid, styrene, methyl methacrylate, methyl acrylate, butyl acrylate, hydroxypropyl acrylate, methacrylamide, acrylamide, and N-methacrylamide.

In some embodiments, at least a portion of the acrylic resin is prepared by: according to the mass parts, 50 parts of propylene glycol methyl ether acetate is heated to 90-110 ℃ under the conditions of stirring and oil bath, and 0.5-1 part of initiator tert-butyl hydroperoxide is added to obtain a mixed solution B; and uniformly mixing 33 parts of acrylic acid, 17 parts of hydroxyethyl methacrylate and 0.3 part of initiator tert-butyl hydroperoxide to obtain a mixed solution C, dropwise adding the mixed solution C into the mixed solution B, adding 0.2 part of initiator tert-butyl hydroperoxide into the reaction system after dropwise adding is finished, and carrying out heat preservation reaction for 0.5-2 h in an oil bath at the temperature of 90-110 ℃ to obtain the acrylic resin.

In step S313, the mixing manner of the hydrophilic resin and the hydrophilic mixed sol may be mechanical mixing, ultrasonic mixing, or other mixing manners as long as the hydrophilic resin and the hydrophilic mixed sol can be uniformly mixed.

In some embodiments, a method of making a composite material comprises: and uniformly mixing 10-30 parts of hydrophilic resin and 70-90 parts of hydrophilic mixed sol, for example, firstly mixing for 10-30 min in an ultrasonic mode, and then mixing for 10-30 min in a mechanical stirring mode. Ultrasonic mixing helps break up large clusters of particles into small clusters, and mechanical agitation mixing helps to mix the individual clusters uniformly. Thus, the hydrophilic resin and the hydrophilic mixed sol can be mixed uniformly, and the advantages of the hydrophilic resin and the hydrophilic mixed sol can be fully exerted, so that the composite material with excellent hydrophilic durability can be obtained.

In other embodiments, the composite material includes a hydrophilic hybrid sol and a polymer formed by polymerizing a monomer, the monomer corresponding to the polymer includes an acryl-based monomer having a hydrophilic group, and step S31 is to provide the composite material for forming the coating layer 2, and further includes the steps of:

s312', providing a solution containing at least one monomer including a hydrophilic group-bearing acryl-based monomer;

s313', mixing the first part of initiator with hydrophilic mixed sol preheated to 70-75 ℃ and used in an amount of 80-95 parts by mass to obtain mixed solution D; mixing 5-20 parts by mass of a solution containing at least one monomer with a second part of initiator to obtain a mixed solution E;

dropwise adding 5-20 parts by mass of the mixed solution E into the mixed solution D, after dropwise adding, adding a third part of initiator into a reaction system, and carrying out heat preservation reaction at the temperature of 60-80 ℃ for 1-3 h to obtain a reaction solution F, wherein the total amount of the first part of initiator, the second part of initiator and the third part of initiator is 0.02 part by mass;

taking 70-95 parts by mass of the reaction solution F and 5-30 parts by mass of a polyvinyl alcohol aqueous solution (the concentration is 4% -8%), and mixing to obtain the composite material.

Specifically, in some embodiments, step S313' includes: heating 80-95 parts of hydrophilic mixed sol to 70-75 ℃, and adding 0.005 part of tert-butyl hydroperoxide. The t-butyl hydroperoxide can serve as an initiator to initiate the polymerization reaction, and the initiator can be replaced by azobisisobutyronitrile, dibenzoyl peroxide, t-amyl peroxide, di-t-butyl peroxide, di-t-amyl peroxide, dicumyl peroxide, 3,3-ethyl bis (t-butylperoxy) butyrate, 3,3-ethyl bis (t-amylperoxy) butyrate, t-butyl peroxybenzoate, t-amyl peroxyacetate, 1,1' -bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2-ethylhexyl t-butyl peroxide, and 2-ethylhexyl t-amyl peroxide.

Then, a mixture of 5 to 20 parts of hydroxyethyl methacrylate and 0.01 part of tert-butyl hydroperoxide is added dropwise to the system, wherein the hydroxyethyl methacrylate is a monomer with double chains, and the hydroxyethyl methacrylate can be replaced by monomers such as methacrylic acid, styrene, methyl methacrylate, methyl acrylate, butyl acrylate, hydroxypropyl acrylate, methacrylamide, acrylamide and N-methacrylamide.

After the addition of the above mixture was completed, 0.005 part of t-butyl hydroperoxide was additionally added to the system. And carrying out heat preservation reaction in an oil bath or a water bath at 70 ℃ for 3h (1-3 h) to obtain a mixed intermediate solution.

It is noted that the total amount of initiator used is about 2wt.% of the hydrophilic hybrid sol and hydroxyethyl methacrylate. The order of addition of the initiator may be changed, and for example, the initiator may be added all before the addition of hydroxyethyl methacrylate, may be added in a mixture with hydroxyethyl methacrylate, or may be added in stages before, during or after the addition of hydroxyethyl methacrylate.

It is noted that in some embodiments, the mixed intermediate liquid may also be used as a composite material, which already enables the formation of a coating with better hydrophilic durability. But to further enhance the durability of subsequent coatings, the following operations are performed.

And (2) ultrasonically mixing 70-95 parts by mass of the mixed intermediate solution and 5-30 parts by mass of a polyvinyl alcohol aqueous solution (the concentration is 4-8%) for 15min, and mechanically stirring for 2h to obtain the final composite material.

The composite material comprising the hydrophilic resin and the hydrophilic mixed sol is applied to a heat exchanger, such as an all-aluminum micro-channel heat exchanger, the initial static contact angle on the surface of the heat exchanger is not more than 10 degrees, the hydrophilic effect is excellent, the preparation process of the composite material is green and environment-friendly, basically no harmful components are discharged, the operation is simple, and the cost is low. The hydrophilic mixed sol in the composite material has good wettability with an aluminum base material, si (silicon) and Al (aluminum) can form Si-O-Al bonds, and the adhesion of the formed coating is improved. The composite material further improves the leveling property of the mixed sol through the addition of the hydrophilic resin, improves the surface state of the coating, improves the compactness of the coating, can also play a certain role in improving the basic corrosion resistance, and particularly can obviously improve the hydrophilic durability of the coating.

In the present application, the composite material for forming the coating layer 2 may be the hydrophilic hybrid sol prepared by the step S311, or the composite material including the hydrophilic hybrid sol and the hydrophilic resin prepared by the steps S311, S312, and S313, or the composite material including the hydrophilic hybrid sol and the polymer prepared by the steps S311, S312', and S313', wherein the polymer is formed by polymerizing monomers, and the corresponding monomer of the polymer includes a acryl-based monomer having a hydrophilic group.

In some embodiments, before step S2 (i.e., connecting the first substrate 11 and the second substrate 12), or before step S3 (i.e., coating the outer surface of at least one of the first substrate 11 and the second substrate 12), the following steps are further included:

s41, performing ultrasonic cleaning treatment on at least one of the first substrate 11 and the second substrate 12;

and S42, drying at least one of the first substrate 11 and the second substrate 12 after the ultrasonic cleaning treatment.

Step S41 may clean the abrasive remaining on the outer surface of at least one of the first base 11 and the second base 12, and reduce the abrasive remaining on the outer surface of the first base 11 and the second base 12.

Steps S41 and S42 will be described below by taking the microchannel heat exchanger described above as an example. In some embodiments, before step S2 (i.e., connecting the first substrate 11, the second substrate 12, and the third substrate 13), or before step S3 (i.e., coating the outer surface of at least one of the first substrate 11, the second substrate 12, and the third substrate 13), the following steps are further included:

s41, performing ultrasonic cleaning treatment on at least one of the first matrix 11, the second matrix 12 and the third matrix 13;

and S42, drying at least one of the first matrix 11, the second matrix 12 and the third matrix 13 after the ultrasonic cleaning treatment.

Step S41 may clean the abrasive remaining on the outer surface of at least one of the first substrate 11, the second substrate 12, and the third substrate 13 to prevent the abrasive remaining on the outer surface of the first substrate 11, the second substrate 12, or the third substrate 13 from affecting the heat exchange efficiency of the heat exchanger and the coating of the subsequent coating.

In order to facilitate understanding of the present invention, the present application has conducted multiple sets of experimental verification. In order to facilitate performance detection, a first base material for forming the heat exchange tube is subjected to sand blasting, and a hydrophilic coating is coated on the outer surface of the first base material subjected to sand blasting.

Example 1

Step 1 Sand blasting

A first substrate is obtained, the width and the thickness of the first substrate are the same as those of the heat exchange tube, and the internal structure of the first substrate is the same as that of the heat exchange tube. The outer surface of the first substrate is smooth.

And sealing the opening of the first base material by using a sealant to prevent the grinding materials from entering the inner cavity in the sand blasting process, and then putting the sealed first base material into a sand blasting machine for sand blasting treatment to obtain a first base body (a sand blasting heat exchange tube). The grain diameter of the abrasive is 120 meshes, the pressure of compressed air is 0.45MPa, the sand blasting angle is 45 degrees, namely the included angle between the spraying direction and the outer surface of the first base material is 45 degrees, and the distance between the spray gun and the first base material during sand blasting is 50mm.

And (3) carrying out sand blasting treatment on the first base material, then carrying out spray washing by using absolute ethyl alcohol, removing the residual abrasive on the surface, and then naturally airing or drying at 40 ℃.

Step 2 applying a coating

Step 2.1 preparation of composite Material

Step 2.1.1 preparation of hydrophilically modified silica sols

Step 2.1.2 preparation of hydrophilic hybrid Sol

Mixing 35 parts by mass of the hydrophilic modified silica sol prepared in the step 3.2.1, 56 parts by mass of commercially available hydrophilic modified silica sol and 5 parts by mass of titanium dioxide sol to obtain a mixed solution, adjusting the pH value of the mixed solution to about 3.0 by adopting 4 parts by mass of a pH value regulator formic acid, and stirring and reacting for 4 hours under the condition of a water bath at 50 ℃ to obtain the hydrophilic mixed sol.

Step 2.1.3

Heating 85 parts by mass of the hydrophilic mixed sol prepared in the step 3.1.2 to 70 ℃, adding 0.005 part of tert-butyl hydroperoxide, dropwise adding a mixture of 15 parts of hydroxyethyl methacrylate and 0.01 part of tert-butyl hydroperoxide, and supplementing 0.005 part of tert-butyl hydroperoxide after dropwise adding. Keeping the temperature in an oil bath or a water bath at 70 ℃ for reaction for 3h to obtain sol M.

Step 2.1.4

According to the mass parts, 80 parts of the sol M and 20 parts of polyvinyl alcohol aqueous solution (the concentration is 4%) are ultrasonically mixed for 15min, and are mechanically stirred for 2h to obtain the composite material.

Step 2.2 formation of the coating

The sample with the surface obtained in the step 1 subjected to sand blasting treatment and without the coating is immersed in the composite material prepared in the step 2.1 in the embodiment, that is, the composite material is coated on the surface of the sample in a dip-coating manner, wherein the dip-coating time is 2min, and the dip-coating frequency is 1 time. After the completion of the dip coating, the coating was cured at 200 ℃ for 10min to obtain a coated sample.

Example 2

Example 2 differs from example 1 in step 2.1.4, the rest of example 2 being the same as example 1.

In this embodiment, step 2.1.4 comprises: and (3) ultrasonically mixing 90 parts of the sol M and 10 parts of a polyvinyl alcohol aqueous solution (the concentration is 4%) for 15min, and mechanically stirring for 2h to obtain the composite material.

Example 3

Example 3 differs from example 1 in step 2.1.1, the other parts of example 3 being the same as example 1.

In this embodiment, step 2.1.1 comprises: mechanically stirring 32 parts of KH560, 8 parts of tetraethoxysilane and 53 parts of absolute ethyl alcohol uniformly under the condition of water bath at the temperature of about 50 ℃, uniformly mixing 2.5 parts of water and 0.5 part of sodium dodecyl sulfate, adding the mixture into a system, then adding 1.5 parts of formic acid and 2.5 parts of water into the system, uniformly mixing, and keeping the reaction conditions unchanged for about 24 hours to obtain the silica sol.

Example 4

Example 4 differs from example 1 in that example 4 does not include step 2.1.4, and accordingly, in the step of preparing the sample, the sample was directly dip-coated with the sol M prepared in step 2.1.3 of example 1 for a dip-coating time of 2min for 1 dip-coating times. After the completion of the dip coating, the coating was cured at 200 ℃ for 10min to obtain a coated sample.

Example 5

Example 5 differs from example 1 in step 2.1.3 and step 2.1.4, the other parts of example 5 being the same as example 1.

In this embodiment, step 2.1 includes, in addition to step 2.1.1 and step 2.1.2:

step 2.1.5: heating 50 parts by mass of propylene glycol methyl ether acetate to 100 ℃ under the conditions of stirring and oil bath, and adding 1 part by mass of tert-butyl hydroperoxide to obtain a mixed solution A; uniformly mixing 33 parts of acrylic acid, 17 parts of hydroxyethyl methacrylate and 0.3 part of tert-butyl hydroperoxide to obtain a mixed solution B, dropwise adding the mixed solution B into the mixed solution A, adding 0.2 part of tert-butyl hydroperoxide into a reaction system after dropwise adding, and carrying out heat preservation reaction for 1h in an oil bath at 100 ℃ to obtain the acrylic resin.

Step 2.1.6: and uniformly mixing 30 parts of acrylic resin and 70 parts of hydrophilic mixed sol by mass to obtain the composite material.

Comparative example 1

In the actual production process of the heat exchanger, in order to realize the assembly of the heat exchange tube, the fins and the current collecting tube, the outer surfaces of the fins and the current collecting tube are covered with the solder, and the heat exchange tube, the fins and the current collecting tube need to be heated in order to melt the solder. In order to simulate the actual production process of the heat exchanger to examine whether the process of the furnace heating affects the roughness of the sandblasted surface, the sample was prepared in the method of the present comparative example.

This comparative example differs from example 1 in that the first substrate was furnace heated after step 1 and before step 2. Specifically, in this embodiment, the following steps are further included after step 1 and before step 2: and heating the first matrix at 580-620 ℃ for 40-60 min.

Comparative example 2

In order to examine whether the order of the blasting treatment and the overburning heating step may have an influence on the roughness of the blast-treated surface, this comparative example preceded the heating step in comparative example 1 to step 1 (i.e., blasting treatment).

The comparative example differs from comparative example 1 in that the first substrate was heated first and then the heat-treated first substrate was subjected to sand blast treatment, and the rest of the comparative example is the same as comparative example 1.

Performance testing

1. Roughness test

Fig. 14 is a scanning electron micrograph of the surface of the first substrate subjected to the sandblasting treatment in example 1. As can be seen in fig. 14, the grit blasting roughens the outer surface of the first substrate.

The surface roughness of the first substrate which was not subjected to the sand blast treatment, the first substrate subjected to only the sand blast treatment in example 1, the first substrate subjected to the sand blast treatment and the furnace heating in this order in comparative example 1, and the first substrate subjected to the furnace heating and the sand blast treatment in this order in comparative example 2 were examined, respectively.

The surface roughness of the first substrate that was not grit blasted was 0.2047. The surface roughness of the first substrate subjected to only the blast treatment in example 1 was 2.7600. The surface roughness of the first base material in comparative example 1 after the sand blast treatment and the furnace heating in this order was 2.8368. The surface roughness of the first base material in comparative example 2 after the sand blast treatment and the furnace heating in this order was 2.8368.

It follows that the overburning, whether performed before or after grit blasting, does not have a significant effect on the surface roughness of the grit blasted first substrate.

2. Hydrophilic Performance test (contact Angle test)

The used test instrument is a contact angle measuring instrument which adopts the optical imaging principle and adopts an image profile analysis mode to measure the contact angle of the sample. The contact angle refers to an angle formed when a liquid phase is clamped between a gas-liquid interface and a solid-liquid interface at a solid-liquid-gas three-phase boundary point on the surface of a solid by dropping a drop of liquid on a horizontal plane of the solid.

During testing, the contact angle measuring instrument and a computer connected with the contact angle measuring instrument are opened, and testing software is opened.

The sample is placed on a horizontal workbench, the volume of liquid drops is adjusted by a microsyringe, the volume is about 1 mu L generally, the liquid drops form liquid drops on a needle head, the workbench is moved upwards by rotating a knob, the surface of the sample is contacted with the liquid drops, and then the workbench is moved downwards, so that the liquid drops can be left on the sample.

The contact angle of this area was obtained by testing and data analysis with test software. The contact angle of the samples of each example and comparative example was determined by averaging 5 different points taken and tested.

The test results of the contact angles show that the initial contact angles of the surfaces of the samples of the examples 1-5 and the comparative examples 1-2 are less than 10 degrees, which shows that the hydrophilic property of the coating formed on the surface of the sample by the composite material is relatively excellent, and the composite material is favorable for promoting the drainage of condensed water in a limited space.

3. Hydrophilic durability test

3.1 Cold Heat alternation test

And (3) placing the samples of the embodiment 1, the embodiment 4 and the embodiment 5 in a cold-hot alternating box, recording the temperature change range of-40-120 ℃ as a cycle, and taking out and drying the samples to dry the coating contact angles corresponding to the test samples at certain cycle times. The test results of example 1 and example 4 are shown in table 1.

Table 1 results of cold-hot alternation test of example 1 and example 4

As can be seen from the data in table 1, the samples of examples 1 and 4 still showed good hydrophilicity after 480 cold and hot cycle tests, with the coating surface contact angles of the samples being around 50 °.

The test results of example 5 are shown in table 2.

Table 2 results of the cold-hot alternation test of example 5

Coating surface hydrophilic durability of the sample of example 5 after 100 hot and cold cycle tests, the sample of example 3 showed a coating surface contact angle of 13.801 ° showing good hydrophilicity.

3.2 flow Water test

The samples of example 2, example 3 and example 4 were immersed in running water, blown dry at intervals, contact angles were measured and the contact angles were recorded for some of the time. The test results are shown in Table 3, respectively.

Table 3 cold-hot alternation test results of examples 2 to 4

As can be seen from the data in table 3, the samples of example 2, example 3 and example 4 still showed good hydrophilicity with the coated surface contact angle of the sample below 50 ° after the running water test for 240 h.

The sample of example 5 was immersed in running water, removed to blow dry at 24h intervals, the contact angle was tested, and the contact angle was recorded for part of the time. The test results are shown in Table 4, respectively.

Table 4 flow test results for example 5

As can be seen from the data in Table 4, after the 520h flowing water test, the contact angle of the coating surface of the sample of example 5 can reach 40.902 degrees, and the sample shows better hydrophilic performance.

While embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the application, the scope of which is defined by the claims and their equivalents.

Claims

1. A heat exchanger, characterized by: the heat exchanger comprises a substrate and a coating, wherein the coating is arranged on at least part of the surface of the substrate,

the base body comprises a first base body and a second base body, at least one of the first base body and the second base body is provided with a groove, and the groove is formed by inwards recessing from the outer surface of at least one of the first base body and the second base body;

2. The heat exchanger of claim 1, wherein: the base body comprises a third base body, and the adhesive or the solder filled in the first groove is in contact with the third base body.

3. The heat exchanger of claim 1, wherein: the heat exchanger comprises a heat exchange tube, fins and a collecting tube, the first base body is the heat exchange tube, and the second base body is the fins or the collecting tube;

the first substrate is provided with a first groove and a second groove, the outer surface of the first substrate comprises a first surface and a second surface, the first surface is connected with the second surface, the first substrate is connected with the second substrate through the first surface, at least part of the second surface is covered with the coating, the first substrate is inwards sunken from the first surface to form the first groove, and the first substrate is inwards sunken from the second surface to form the second groove.

4. The heat exchanger of claim 3, wherein: the first substrate is provided with at least two first surfaces, and at least part of the second surface is positioned between two adjacent first surfaces of the same first substrate.

5. The heat exchanger of claim 3, wherein: the first surface and the second surface are both rough surfaces, and the roughness ranges from 0.5 mu m to 10 mu m.

6. A method of manufacturing a heat exchanger, the method comprising the steps of:

connecting the first base body and the second base body, so that the first groove is filled with adhesive or solder, and the adhesive or the solder filled in the first groove is contacted with the first base body and the second base body;

at least part of the outer surface of at least one of the first substrate and the second substrate is covered with a coating, so that at least part of the coating is positioned in the second groove, the coating comprises micro-nano particles, and the micro-nano particles comprise hydrophilic modified silicon dioxide and/or titanium dioxide.

7. The method of manufacturing a heat exchanger according to claim 6, comprising the steps of:

providing a third substrate;

connecting the first substrate, the second substrate, and the third substrate such that the adhesive or the solder filled in the first groove is in contact with each of the first substrate, the second substrate, and the third substrate.

8. The method of manufacturing according to claim 6, wherein said providing a first substrate and a second substrate comprises the steps of:

providing a substrate comprising a first substrate for forming the first matrix and a second substrate for forming the second matrix;

grit blasting an outer surface of at least one of the first substrate and the second substrate.

9. The method of manufacturing according to claim 8, wherein said providing a first substrate and a second substrate comprises the steps of:

cutting at least one of the first substrate and the second substrate.

10. The method of manufacturing according to claim 6, wherein providing a coating on at least a portion of an outer surface of at least one of the first substrate and the second substrate comprises the steps of:

providing a composite material for forming a coating, wherein the composite material comprises micro-nano particles, and the micro-nano particles comprise at least one of hydrophilic modified silicon dioxide and titanium dioxide;

and coating the composite material on at least part of the outer surface of at least one of the first substrate and the second substrate, and curing to form the coating.