WO2023143324A1 - 换热器、用于换热器的复合材料和换热器的表面处理方法 - Google Patents

换热器、用于换热器的复合材料和换热器的表面处理方法 Download PDF

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Publication number
WO2023143324A1
WO2023143324A1 PCT/CN2023/072969 CN2023072969W WO2023143324A1 WO 2023143324 A1 WO2023143324 A1 WO 2023143324A1 CN 2023072969 W CN2023072969 W CN 2023072969W WO 2023143324 A1 WO2023143324 A1 WO 2023143324A1
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WIPO (PCT)
Prior art keywords
heat exchanger
particles
coating
kinds
hydrophobic
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PCT/CN2023/072969
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English (en)
French (fr)
Inventor
唐建华
余书睿
黄海
黄宁杰
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浙江三花智能控制股份有限公司
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Publication of WO2023143324A1 publication Critical patent/WO2023143324A1/zh

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F28D1/05308—Assemblies of conduits connected side by side or with individual headers, e.g. section type radiators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
    • F28F19/02—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings
    • F28F19/04—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers by using coatings, e.g. vitreous or enamel coatings of rubber; of plastics material; of varnish
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency

Definitions

  • the present disclosure relates to heat exchange devices, and in particular to a heat exchanger, a composite material for the heat exchanger and a surface treatment method for the heat exchanger.
  • a hydrophobic sol is coated on the surface of the heat exchanger to form a hydrophobic coating.
  • the hydrophobic coating makes the corrosive solution have a larger contact angle on the surface of the heat exchanger, is not easy to spread, and reduces the direct contact area between the corrosive solution and the surface of the heat exchanger.
  • the hydrophobic coating itself also has a certain barrier effect on corrosive media. Therefore, the hydrophobic coating can improve the corrosion resistance of the heat exchanger.
  • the hydrophobic coating formed by the hydrophobic sol inevitably has some microporous defects or pores inside.
  • fillers can be added to the hydrophobic sol to increase the hydrophobic coating. layer density.
  • most studies focus on the effect of filler content on the anti-corrosion effect of hydrophobic coatings, but less attention is paid to the effect of the shape of particles contained in the filler on the anti-corrosion effect of hydrophobic coatings.
  • related technologies can also start from the particle shape to improve the corrosion resistance of the heat exchanger.
  • the purpose of the present disclosure is to provide a heat exchanger with good corrosion resistance.
  • the present disclosure also provides a composite material for the heat exchanger and a surface treatment method for the heat exchanger.
  • the present disclosure provides a heat exchanger comprising:
  • the heat exchanger has a channel for fluid circulation, and the hydrophobic coating includes a low surface energy silane material and a filler dispersed in the low surface energy silane material, wherein the filler includes two kinds of particles, the Each of the two kinds of particles has a shape, and the shapes of the two kinds of particles are different.
  • the hydrophobic coatings of the present disclosure include low surface energy silane-based materials and fillers.
  • the filler in the hydrophobic coating of the present disclosure includes two kinds of particles, each of the two kinds of particles has one shape, and the two kinds of particles are different in shape. different shapes
  • the combination of particles is beneficial to increase the compactness of the coating, increase the barrier effect of the hydrophobic coating on the corrosive medium, and improve the corrosion resistance of the heat exchanger.
  • the present disclosure also provides a composite material for a heat exchanger, comprising:
  • the low surface energy silane materials include silane grafted with hydrophobic groups on the surface, and the hydrophobic groups are selected from at least one of hydrocarbon groups, halogen atoms and nitro groups;
  • a filler comprising two kinds of particles, each of the two kinds of particles having a shape, and the shapes of the two kinds of particles being different.
  • the composite material of the present disclosure forms a hydrophobic coating containing particles of two shapes on the surface of the heat exchanger, thereby improving the corrosion resistance of the heat exchanger.
  • the present disclosure also provides a surface treatment method for a heat exchanger, comprising the following steps:
  • a composite material is provided, the composite material includes a low surface energy silane-based material and a filler, the filler includes two kinds of particles, each of the two kinds of particles has a shape, and the shapes of the two kinds of particles are different;
  • the composite material is coated on at least part of the surface of the heat exchanger, and cured to form a hydrophobic coating on at least a part of the surface of the heat exchanger.
  • the surface treatment method of the heat exchanger disclosed herein can form a hydrophobic coating containing particles of two shapes on the surface of the heat exchanger, thereby improving the corrosion resistance of the heat exchanger.
  • FIG. 1 is a schematic diagram of the microscopic morphology of irregularly shaped particles in an embodiment of the present disclosure
  • FIG. 2 is a schematic diagram of the microscopic morphology of three-dimensional dendritic particles in an embodiment of the present disclosure
  • Fig. 3 is a schematic structural diagram of a heat exchanger in an embodiment of the present disclosure
  • Fig. 4 is an enlarged schematic diagram of the assembly structure of some components of the heat exchanger in Fig. 3;
  • FIG. 5 is a schematic cross-sectional view of a hydrophobic coating on the surface of a heat exchanger substrate in an embodiment of the present disclosure
  • FIG. 6 is a schematic cross-sectional view of a hydrophobic coating and a rare earth conversion film on the surface of a heat exchanger substrate in an embodiment of the present disclosure
  • Fig. 7 is the sample surface morphology of Comparative Example 1 and Comparative Example 2 in the 48h salt spray test of the present disclosure
  • Fig. 8 is the sample surface morphology of Comparative Example 1 and Comparative Example 2 in the 96h salt spray test of the present disclosure
  • Fig. 9 is the sample surface morphology of Example 1 and Comparative Example 1 in the 96h salt spray test of the present disclosure.
  • the anti-corrosion coating on the surface of heat exchanger products on the market are chemical conversion coatings.
  • the anti-corrosion coating on the surface of aluminum heat exchanger is mostly chemical conversion coating (TCP) formed by chromium salt passivation.
  • TCP chemical conversion coating
  • hexavalent chromium is highly toxic and carcinogenic
  • the use of hexavalent chromium passivation coatings has been strictly prohibited at home and abroad.
  • the current market uses trivalent chromium instead of hexavalent chromium for surface anticorrosion treatment of aluminum products, but trivalent chromium is harmful to the environment and human body Still can't be ignored.
  • a hydrophobic sol is coated on the surface of the heat exchanger, and the hydrophobic sol is solidified on the surface of the heat exchanger to form a hydrophobic coating.
  • the formed hydrophobic coating can be It is firmly combined with the heat exchanger substrate.
  • the hydrophobic coating makes the corrosive solution have a larger contact angle on the surface of the heat exchanger, is not easy to spread, and reduces the direct contact area between the corrosive solution and the surface of the heat exchanger.
  • the hydrophobic coating itself also has a certain physical barrier or physical shielding effect on the corrosive medium, which can reduce the contact between the metal substrate and external substances (such as oxygen, water or other corrosive substances). In this way, on the one hand, the chemical corrosion of the metal substrate surface by acid and alkali is reduced or slowed down; Corrosion is also reduced or slowed to some extent. Therefore, the hydrophobic coating can improve the corrosion resistance of the heat exchanger.
  • the improvement of the corrosion resistance of the hydrophobic coating mainly depends on its hydrophobic performance and its internal microstructure.
  • the hydrophobic property of the hydrophobic coating comes from the hydrophobic groups in the hydrophobic coating, and the internal microstructure of the hydrophobic coating is largely affected by the crosslinking degree of the hydrophobic sol.
  • the coating formed by the sol with a small degree of crosslinking has more pores inside, and the more pores, the smaller the barrier effect of the coating itself.
  • the degree of crosslinking increases, the density, mechanical strength and hardness of the coating increase, and the barrier effect of the coating itself also increases.
  • excessive crosslinking will increase the brittleness of the coating, resulting in increased microcracks on the coating surface and even rupture.
  • the hydrophobic sol In order for the hydrophobic coating to be firmly attached to the metal substrate without causing more microcracks or even ruptures inside the coating, the hydrophobic sol needs to have an appropriate degree of crosslinking. Generally, the hydrophobic coating formed by hydrophobic sol inevitably has some microporous defects or pores inside, and these microporous defects or pores are easy to become the path for the corrosion medium to diffuse to the metal substrate. For this purpose, fillers can be added to the hydrophobic sol.
  • the filler is composed of many particles.
  • the particles that make up the filler are filled in the microporous defects or pores of the hydrophobic coating, which can block the transmission path of the corrosive medium, hinder the transmission and diffusion of the corrosive medium in the hydrophobic coating, and increase the hydrophobic coating.
  • the density and thickness of the coating improve the barrier effect of the hydrophobic coating itself on corrosive substances.
  • most studies focus on the effect of the filler content in the hydrophobic coating on the anti-corrosion effect of the hydrophobic coating, but less attention is paid to the effect of the shape of the particles contained in the filler on the anti-corrosion effect of the hydrophobic coating.
  • a first aspect of the present disclosure provides a heat exchanger, the heat exchanger has a channel for fluid communication, the heat exchanger includes a substrate and a coating covering at least part of the surface of the substrate, the coating includes a hydrophobic coating,
  • the hydrophobic coating includes a low surface energy silane material and a filler dispersed in the low surface energy silane material, the filler includes two kinds of particles, each of the two kinds of particles has a shape, and the shapes of the two kinds of particles are different.
  • the filler includes more than three kinds of particles, at least two of which have different shapes.
  • the low surface energy silane-based material refers to a silane-based material with low surface energy. When the surface energy of the material is low, it can exhibit certain hydrophobic properties.
  • the hydrophobic coating of the present disclosure includes low surface energy silane materials and fillers, the particles included in the fillers are filled in the network structure of the low surface energy silane materials, and are firmly combined with the heat exchanger matrix through the low surface energy silane materials.
  • Microporous defects or pores in low surface energy silane-based materials have a wide variety of shapes. From the perspective of pore filling, the higher the degree of matching between particles and pores in shape, the better the filling effect of particles. For example, for irregularly shaped pores, the filling of irregularly shaped particles can achieve a better filling effect, and for regular shaped pores, it needs to be filled with matching particles to achieve better filling effect.
  • the variety of particle shapes is beneficial to the filling of pores.
  • the filler in the hydrophobic coating of the present disclosure includes two kinds of particles, each of the two kinds of particles has one shape, and the two kinds of particles are different in shape.
  • the combination of different shapes of particles makes the particles have a good filling effect in the hydrophobic coating, which is beneficial to increase the compactness of the coating, increase the barrier effect of the hydrophobic coating to the corrosive medium, and improve the corrosion resistance of the heat exchanger.
  • the addition of fillers is usually carried out in the form of adding one or several particles, rather than in the form of adding one or several particles.
  • the number of each particle in the coating is measured in tens, hundreds, thousands, tens of thousands, tens of millions, hundreds of millions, hundreds of millions, or even trillions.
  • one particle may include 10, 10 2 , 10 3 , 10 4 , 10 5 , 10 6 , 10 7 , 10 8 , 10 9 , 10 10 and so on in numbers.
  • the addition of fillers focuses on the type of particles, not the number of particles.
  • the focus is not on the shape of one or several particles, but on the commonality of the shape of the particles included in one particle and the difference in shape of more than two kinds of particles. impact of the difference.
  • the chemical composition and shape of the particles included in one kind of particle are approximately the same, and one kind of particle corresponds to one kind of chemical composition and one kind of particle shape.
  • the particle shape is mainly related to the preparation process.
  • Common preparation techniques include ball milling, jet milling, gas atomization, water atomization, and chemical methods.
  • the shape of the obtained particles is also different.
  • the powder particles obtained by strip jet milling are flakes
  • the powder particles prepared by water atomization or gas atomization are spherical
  • the silica powder particles prepared by precipitation method are roughly spherical
  • the powder particles prepared by gas phase method are spherical.
  • the silica powder particles roughly present a three-dimensional dendritic shape. Affected by the preparation process conditions, the shape of all the particles included in a particle may not be exactly the same.
  • a particle shape corresponding to a particle refers to most of the particles included in the particle.
  • the shape of the particles (for example, the number accounts for 50%, 60%, 70%, 80%, 90%, 99%).
  • 99% of the particles of a compound A are spherical, while the remaining 1% of the particles are droplet-shaped.
  • one of the two particles is irregular in shape.
  • Particles are filled into the network structure of low surface energy silane materials. Not all particles can completely match the pores they fill, so the particles fill into the pores, and there may still be some unfilled gaps on the outer surface of the particles.
  • the strength, hardness and wear resistance of the particles themselves are better than those of low surface energy silane materials, so the gaps between the particles become the main path for the corrosive medium to penetrate the coating to reach the heat exchanger substrate.
  • the tortuousness, length, etc. of the transmission path of the corrosive medium in the hydrophobic coating largely depend on the surface morphology of the particles, or the shape of the particles.
  • the shape of particles can be divided into regular shape and irregular shape.
  • Regular shapes usually refer to shapes with certain mathematical laws in the dimension of point, line or surface, such as sphere, ellipsoid, rod, needle, sheet, column, hexahedron, tetrahedron, dendrite, three-dimensional branch status etc.
  • Regularly shaped particles can usually be described by regular features in their shape.
  • Irregular shapes are shapes that have no obvious mathematical laws in the dimensions of points, lines, and surfaces, as shown in Figure 1, compared to regular shapes.
  • irregular-shaped particles can increase the tortuosity of the transmission path of the corrosive medium. Because no matter between irregularly shaped particles, or between irregularly shaped particles and regular shaped particles, the gaps are irregular. Therefore, the introduction of irregularly shaped particles is beneficial to hinder the penetration and diffusion of corrosive media in the hydrophobic coating, and prolong the time for the corrosive medium to penetrate the hydrophobic coating to reach the heat exchanger substrate, thereby further improving the corrosion resistance of the hydrophobic coating.
  • the barrier effect of the medium improves the corrosion resistance of the heat exchanger.
  • irregularly shaped particles also have good slip resistance, which is conducive to maintaining the consistency and stability of the hydrophobic coating.
  • the chemical composition of the two particles is different.
  • the shape of the particles is mainly affected by the preparation process.
  • the same material can be used to prepare different kinds of particles.
  • flake-shaped particles are prepared by jet milling alumina strips
  • spherical particles are prepared by aluminum oxide gas atomization
  • flake-shaped alumina particles and spherical alumina particles are added to the hydrophobic coating to achieve different shapes of particles in the coating.
  • different kinds of particles can also be prepared with different materials and through different preparation processes. For example, irregular particles of alumina are compounded with three-dimensional dendritic particles of fumed silica.
  • particles made of different materials have different physical and chemical properties, such as strength, hardness, wear resistance, etc.
  • adding them to the coating can strengthen the hydrophobic coating in different aspects.
  • the present disclosure can also employ particles that differ in chemical composition.
  • the irregularly shaped particles are selected from one of aluminum oxide, zinc oxide, zirconium oxide, titanium oxide, silicon oxide, lanthanum oxide, cerium oxide, praseodymium oxide, boron nitride, and barium sulfate. These compounds have good strength, hardness and wear resistance, and when added as fillers to hydrophobic coatings, they can permanently enhance the corrosion resistance of hydrophobic coatings.
  • the shape of at least one of the two particles is a regular shape, and the regular shape is selected from spherical, ellipsoidal, rod-like, needle-like, flake-like, columnar, hexahedral, tetrahedral, and dendritic. , one of the three-dimensional dendrites.
  • the present disclosure also incorporates regular-shaped particles in the hydrophobic coating to increase the diversity of particle shapes.
  • the three-dimensional dendritic particles are fumed silica particles.
  • Fig. 2 schematically shows the shape of fumed silica particles.
  • the regularly shaped particles are selected from the group consisting of alumina, zinc oxide, zirconia, titania, silica, lanthanum oxide, cerium oxide, praseodymium oxide, boron nitride, graphene, graphene oxide, carbon nanotubes, and One of barium sulfate.
  • the particle diameters of the two kinds of particles are in the range of 10-100 nm.
  • the particles are filled in the network structure of low surface energy silane materials, too large or too small particle size will weaken the barrier effect of the coating itself on the corrosive medium: particles with too large particle size will increase the internal defects of the coating ; Particles with too small particle size are easy to agglomerate in the coating and are not easy to disperse, so that they cannot be evenly filled in the micropores or pores of the network structure of low surface energy silane materials.
  • the hydrophobic coating on the surface of the heat exchanger in the present disclosure is relatively thin.
  • the present disclosure selects the particle size range of 10-100 nm, so that the particles can be uniformly filled in the network structure of the low surface energy silane material without significantly increasing the internal defects of the coating.
  • the particle size of a particle is usually within a fixed particle size range.
  • the filler is alumina particles.
  • the particle size range of alumina particles is described as 20-40nm, it means that the particle diameters of the alumina particles added to the hydrophobic coating are all in the range of 20-40nm.
  • a particle also has an average particle size.
  • the average particle size of a particle theoretically refers to the The average particle size of the particle.
  • the two types of particles include a first type of particle and a second type of particle, and the average particle size of the first type of particle is 2 to 10 times that of the second type of particle.
  • the sizes of pores in low surface energy silane materials are also various.
  • the present disclosure uses particles with different average particle sizes, which can improve the filling effect of particles on pores on the one hand, and on the other hand, the compounding of particles with different particle sizes also has It is beneficial to increase the compactness of the coating.
  • the first particle is a regular-shaped particle and the second particle is an irregular-shaped particle; or, the first particle is an irregular-shaped particle and the second particle is a regular-shaped particle.
  • the content ratio of the first particle and the second particle in the hydrophobic coating is 1:1 ⁇ 1:5.
  • both particles are poorly or slightly soluble compounds in water.
  • the solubility is less than 0.01g is poorly soluble, the solubility is greater than 0.01g and less than 1g is slightly soluble, the solubility is greater than 1g and less than 10g is soluble, and the solubility is greater than 10g is easily soluble.
  • Insoluble or slightly soluble particles can exist stably in the hydrophobic coating for a long time, so as to achieve a lasting improvement in the anti-corrosion performance of the hydrophobic coating.
  • the resistivities of the two kinds of particles are both 10 9 to 10 22 ⁇ cm. That is, the particles are prepared from insulating materials. In this way, the particles can also use the insulating properties to slow down the transfer of ions between the cathode and anode in the electrochemical corrosion primary battery, and have a certain hindering effect on the overflow of metal cations in the anode and the discharge effect generated by the cathode, that is, it has a resistance effect, reducing or Slow down the electrochemical corrosion of the surface of the metal substrate.
  • hydrophobic groups are grafted on the surface of at least part of the particles of at least one of the two types of particles, and the hydrophobic groups are selected from at least one of hydrocarbon groups, halogen atoms and nitro groups.
  • the halogen atom can be -F, -Cl, -Br, -I, -At; the chemical formula of nitro is -NO 2 .
  • Hydrophobic treatment can be carried out on the particles to make them have certain hydrophobic properties due to the hydrophobic groups grafted on the surface. Filling particles with certain hydrophobic properties into the hydrophobic coating can increase the hydrophobicity of the hydrophobic coating.
  • the low surface energy silane material includes silane grafted with hydrophobic groups on the surface, and the hydrophobic groups are selected from at least one of hydrocarbon groups, halogen atoms and nitro groups.
  • the halogen atom can be -F, -Cl, -Br, -I, -At; the chemical formula of nitro is -NO 2 .
  • the low surface energy silane-based materials can be selected from heptadecafluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecylfluorooctyltriethoxysilane, decafluorodecyltriethoxysilane, One or more of octaltrimethoxysilane and hexadecyltrimethoxysilane.
  • the hydrophobic coating includes 0.5-1.5 parts of low surface energy silane-based materials and 0.1-5 parts of fillers.
  • Parts by mass refers to the basic measurement unit of the mass ratio relationship of multiple components.
  • One part can represent any unit mass, for example, one part can be expressed as 1g, 1.68g, or 5g, etc.
  • the filler content or the ratio of fillers to low surface energy silane materials is a key factor affecting corrosion resistance. If the filler content is too small, the anti-corrosion effect of the coating cannot be optimized. If the filler content is too large, the compatibility between the filler and the low surface energy silane material will decrease, and the filler will be dispersed unevenly in the hydrophobic coating, eventually resulting in hydrophobicity. The poor uniformity of the coating performance will increase the defects and cracks inside the hydrophobic coating, and even cause the coating to crack, and it will also reduce the hydrophobic performance of the coating.
  • the static contact angle of the hydrophobic coating with water is greater than 150°, and the water drop rolling angle of the hydrophobic coating is less than 5°.
  • the hydrophobic coating has better hydrophobic performance.
  • the rare earth conversion coating includes a rare earth compound
  • at least part of the rare earth conversion coating is located between the substrate and the hydrophobic coating.
  • the rare earth conversion coating is located between the substrate and the hydrophobic coating, which means that one side of the rare earth conversion coating is in direct contact with the substrate, and the other side of the rare earth conversion coating is in direct contact with the hydrophobic coating.
  • the hydrophobic coating is farther away from the substrate than the rare earth conversion coating.
  • the membrane is sandwiched between the heat exchanger substrate and the hydrophobic coating, and the hydrophobic coating is attached to the surface of the heat exchanger substrate through the rare earth conversion film.
  • the hydrophobic coating on the surface of the heat exchanger substrate can be in direct contact with the heat exchanger substrate; or, there is a rare earth conversion coating between the hydrophobic coating and the heat exchanger substrate; or, the hydrophobic coating A part of the hydrophobic coating is in direct contact with the heat exchanger substrate, and there is a rare earth conversion film between the other part of the hydrophobic coating and the heat exchanger substrate.
  • the rare earth conversion coating can be entirely located between the heat exchanger substrate and the hydrophobic coating;
  • the base of the heat exchanger is in direct contact with the other side exposed to the external environment, that is, the other part of the rare earth conversion coating is no longer covered with a hydrophobic coating, and a part of the surface of the heat exchanger is only covered with a rare earth conversion coating.
  • the rare earth compound in the rare earth conversion coating can further improve the corrosion resistance of the heat exchanger.
  • the rare earth compounds include rare earth oxides and/or rare earth hydroxides.
  • the rare earth compound may be cerium oxide (CeO 2 ), cerium trioxide (Ce 2 O 3 ), cerium hydroxide (Ce(OH) 4 ), or the like.
  • the rare earth compound can also be other rare earth elements, such as compounds of La, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc, Y.
  • the heat exchanger includes a header, fins, and a plurality of heat exchange tubes, and the heat exchange tubes are connected to the header. Fixed, the inner cavity of the heat exchange tube communicates with the inner cavity of the header, at least part of the fins are fixed between two adjacent heat exchange tubes, the base includes the header, the heat exchange tube and the fins at least one of the substrates. That is, the heat exchanger is a microchannel heat exchanger.
  • a hydrophobic coating, or a hydrophobic coating and a rare earth conversion coating, is coated on at least a portion of a surface of at least one of the headers, heat exchange tubes, and fins.
  • the heat exchanger of the present disclosure is exemplarily described below by taking a microchannel heat exchanger as an example.
  • the present disclosure provides a heat exchanger 100 .
  • the heat exchanger 100 includes a header 11 , a plurality of heat exchange tubes 12 and a plurality of fins 13 .
  • a plurality of heat exchange tubes 12 are fixed to the header 11, and the heat exchange tubes 12 are provided with a plurality of channels 122 for refrigerant circulation, and the plurality of channels 122 of the heat exchange tubes 12 are all connected to the manifold 11.
  • the inner cavity of the header 11 communicates, and at least part of the fins 13 are fixed between two adjacent heat exchange tubes 12 .
  • the header 11 is provided with a fluid inlet 101 and a fluid outlet 102 communicating with its inner cavity, so as to facilitate the fluid to enter the heat exchanger.
  • a plurality of heat exchange tubes 12 are arranged along the length direction of the header 11 , and the length direction of the header 11 can refer to the X direction in FIG. 3 or FIG. 4 .
  • the heat exchange tube 12 is a longitudinally extending tubular structure.
  • the length direction of the heat exchange tube 12 can refer to the Y direction in FIG. 3 or FIG. 4
  • the width direction of the heat exchange tube 12 can refer to the D direction in FIG. 4 .
  • the dimension of the heat exchange tube 12 in the width direction is larger than the dimension of the heat exchange tube 12 in the thickness direction, and the thickness direction of the heat exchange tube 12 substantially coincides with the length direction of the header 11 .
  • the width direction of the heat exchange tube 12 is not in the same direction as the length direction of the header 11 .
  • the width direction (direction D) of the heat exchange tubes 12 is substantially perpendicular to the longitudinal direction (direction X) of the header 11 .
  • FIG. 3 there are two headers 11 , and both ends of the heat exchange tubes 12 in the length direction are respectively inserted into the lumens of the two headers 11 .
  • This type of heat exchanger is also commonly referred to as a single-row heat exchanger in the industry.
  • the number of headers 11 may be one or more than two.
  • the number of heat exchange tubes and fins is also set according to actual product needs.
  • the fins 13 are corrugated along the length direction (Y direction) of the heat exchange tube 12 .
  • the fin 13 includes a plurality of fin units 131 arranged along the length direction of the heat exchange tube 12, and the plurality of fin units 131 are connected in sequence along the length direction of the heat exchange tube 12, and two adjacent fin units 131 are connected.
  • the peaks or troughs in the wave structure corresponding to the fins 13 are formed at the positions, and the fins 13 are fixed to the heat exchange tubes 12 at the positions where two adjacent fin units 131 are connected.
  • parts such as the header 11, fins 13, and heat exchange tubes 12 can be pre-assembled together, and the header 11 and the heat exchange tube 12 are fixed through a brazing process, and the fins 13 are fixed on two adjacent sides. between the heat exchange tubes.
  • the heat exchanger 100 includes a substrate 100-1 and a hydrophobic coating 14 covering at least part of the surface of the substrate 100-1,
  • the base 100 - 1 is a base of at least one of the header 11 , the heat exchange tube 12 and the fin 13 .
  • Fig. 5 is a schematic cross-sectional view of the surface of the heat exchanger base body in one embodiment of the present disclosure.
  • the surface of the heat exchanger substrate 100-1 is covered with a hydrophobic coating 14, the hydrophobic coating includes a low surface energy silane material 141 and two kinds of particles dispersed in the low surface energy silane material, one of which is The shape of the particles is irregular, and the shape of another particle is three-dimensional dendritic.
  • the irregular-shaped particles 142 and the three-dimensional dendritic particles 143 are mixed and filled in the low surface energy silane material 141 .
  • R1 and R2 are used to show the transmission path of the corrosive medium in the hydrophobic coating.
  • FIG. 6 is a schematic cross-sectional view of the surface of a heat exchanger substrate according to another embodiment of the present disclosure. As shown in Figure 6, the surface of the heat exchanger base 100-1 is covered with a rare earth conversion film 15, the rare earth conversion film 15 includes a rare earth compound 151 (shown as a triangle), and the rare earth conversion film 15 is located between the heat exchanger base 100-1 and Between the hydrophobic coating 14.
  • the heat exchanger of the present disclosure can also be a plate heat exchanger, a tube-fin heat exchanger, a shell-and-tube heat exchanger, a round-tube-fin heat exchanger, a water-cooled plate, a direct-cooled plate Heat exchangers for refrigerant or coolant flow.
  • the hydrophobic coating of the present disclosure, or the hydrophobic coating and the rare earth conversion film can be used not only for channel heat exchangers, but also for plate heat exchangers, tube-fin heat exchangers, and shell-and-tube heat exchangers. Surface anti-corrosion treatment of heat exchangers, round tube-fin heat exchangers, water-cooled plates, direct-cooled plates and other heat exchangers.
  • a second aspect of the present disclosure provides a surface treatment method for a heat exchanger, which sequentially includes:
  • Step S11 providing a heat exchanger
  • Step S21 providing a composite material, the composite material includes a solvent, a low surface energy silane material and a filler, the filler includes two kinds of particles, each of the two kinds of particles has a shape, and the shapes of the two kinds of particles are different;
  • Step S31 coating the composite material on at least part of the surface of the heat exchanger provided in S11, and curing to form a hydrophobic coating covering at least part of the surface of the heat exchanger.
  • the substrate of the heat exchanger provided in step S11 is subjected to surface blasting treatment.
  • the surface blasting treatment specifically includes: performing 100-200 mesh white corundum sandblasting on the surface of the heat exchanger, the sandblasting angle is 30°-60°, and the distance between the spray gun and the workpiece is 30-60mm , the number of sandblasting is greater than or equal to 1, and then use alcohol or water to ultrasonically clean or spray the surface of the heat exchanger, and then dry it in the air or at 35°C to 50°C.
  • Sand blasting can increase the roughness of the surface of the heat exchanger, so that the adhesion of the hydrophobic coating on the surface of the heat exchanger substrate is more stable.
  • the roughness Ra of the surface of the heat exchanger substrate is 0.5 ⁇ m to 10 ⁇ m. In an embodiment, the roughness Ra of the surface of the heat exchanger substrate is 1 ⁇ m to 3 ⁇ m. For example, it can be 1 ⁇ m, 1.2 ⁇ m, 1.4 ⁇ m, 1.6 ⁇ m, 1.8 ⁇ m, 2.0 ⁇ m, 2.2 ⁇ m, 2.4 ⁇ m, 2.6 ⁇ m, 2.8 ⁇ m, 3 ⁇ m and so on.
  • the way of coating the composite material on at least part of the surface of the heat exchanger includes but not limited to at least one of dip coating, spray coating, brush coating, flow coating or roller coating.
  • the curing method may be, for example, drying in an oven.
  • the curing temperature is 60-180°C.
  • the curing time is 5-35 minutes.
  • step S41 before step S31 and after step S11, further include: step S41, forming a rare earth conversion film on the surface of the heat exchanger substrate.
  • step S41 may be before step S21 or after step S21.
  • step S41 includes: preparing a rare earth conversion solution, immersing the heat exchanger in the rare earth conversion solution, taking out the heat exchanger, and then drying the surface of the heat exchanger.
  • the rare earth conversion liquid can also be dip-coated, spray-coated, brush-coated, flow-coated or rolled-coated on the surface of the heat exchanger.
  • the rare earth conversion solution includes a rare earth raw material, an oxidizing agent and water.
  • the rare earth conversion solution includes 1-3 parts of rare earth raw materials, 92.5-97.5 parts of water and 1.5-4.5 parts of oxidizing agent.
  • the preparation method of the rare earth conversion liquid includes: dissolving the rare earth raw material in water, and then adding an oxidizing agent to prepare the rare earth conversion liquid.
  • the preparation method of the rare earth conversion liquid may include: in parts by mass, dissolving 1 to 3 parts of rare earth raw materials in 92.5 to 97.5 parts of deionized water, and mixing to obtain an intermediate liquid; heating the intermediate liquid to 45° C. to 55° C., then add 1.5 to 4.5 parts of an oxidizing agent into the system, and continue mixing to obtain a rare earth conversion liquid.
  • the above-mentioned rare earth raw materials are raw materials that can provide rare earth elements, such as raw materials that can provide cerium (Ce) element.
  • the rare earth raw material includes, but is not limited to, one of cerium nitrate hexahydrate, anhydrous cerium nitrate, cerium chloride and its polyhydrates, cerium sulfate and its polyhydrates, cerium acetate and its polyhydrates one or a combination of at least two.
  • the above-mentioned cerium chloride and its polyhydrates are anhydrous cerium chloride, polyhydrates of cerium chloride such as cerium chloride heptahydrate or cerium chloride octahydrate.
  • cerium sulfate and polyhydrates thereof are polyhydrates of anhydrous cerium sulfate and cerium sulfate such as cerium sulfate tetrahydrate; cerium acetate and polyhydrates thereof are polyhydrates of anhydrous cerium acetate and cerium acetate such as three Cerium acetate water or cerium acetate tetrahydrate, etc.
  • the oxidizing agent includes, but is not limited to, at least one of hydrogen peroxide, sodium perchlorate, and t-butyl hydroperoxide.
  • the oxidizing agent can be hydrogen peroxide aqueous solution (the mass concentration of hydrogen peroxide is about 27.5wt.% ⁇ 30wt.%), or the oxidizing agent can be sodium perchlorate, or the oxidizing agent can be tert-butyl hydroperoxide soluble liquid or n-butanol solution of tert-butyl hydroperoxide (the mass concentration of tert-butyl hydroperoxide is not less than 60wt.%).
  • the third aspect of the present disclosure also provides a composite material for a heat exchanger, the composite material includes a solvent, a low surface energy silane material and a filler, the filler includes two kinds of particles, each of the two kinds of particles has a Shape, the shapes of the two particles are different.
  • the composite material can form an anticorrosion coating containing particles of two shapes on the surface of the heat exchanger, thereby improving the corrosion resistance of the heat exchanger.
  • the solvent is selected from at least one of ethanol, methanol, and isopropanol.
  • the composite material in terms of parts by mass, includes 93.5 to 99.4 parts of solvent, 0.5 to 1.5 parts of low surface energy silane materials and 0.1 to 5 parts of filler, the filler includes two kinds of particles, each of the two kinds of particles One kind has one shape, and the two kinds of particles have different shapes.
  • the composite material provided in step S21 is obtained by self-made.
  • a fourth aspect of the present disclosure provides a method for preparing a composite material.
  • the method for preparing a composite material includes: mixing a solvent, a low surface energy silane material, and a filler to obtain a composite material, wherein the filler includes two kinds of particles, and the two kinds of particles Each of the two particles has a shape, and the shapes of the two particles are different.
  • the mixing can be mechanical stirring, ultrasonic dispersion or other methods of mixing; the addition of the raw materials can be added to the solvent at one time, or the solvent can be added in two or more times.
  • the feeding method and feeding times are not limited.
  • at least one of the two particles is added to the solvent in two or more additions. In this way, it is beneficial to the dispersion of the filler in the composite material, so that the filler is evenly dispersed in the network structure formed by the low surface energy silane material.
  • the plate is used instead of the heat exchanger for sample preparation. That is to say, a plate made of the same material as the heat exchanger is used, and relevant paint is applied on the plate to form a coating for testing.
  • the surface treatment of the heat exchanger can adopt the same steps as the surface treatment of the plates in this embodiment.
  • the angle between the spray gun and the position to be coated is about 45°C
  • the distance between the spray gun and the position to be coated is 50mm
  • sandblast once and then spray the plate with absolute ethanol Clean and dry at 40°C for later use.
  • Step 2.1 Weigh 1 part of cerium nitrate hexahydrate into a beaker, add 95.1 parts of deionized water, and stir mechanically until the solids are completely dissolved, and the solution is colorless and transparent. Heat the solution in a water bath to 50°C, add 2.4 parts of n-butanol solution of tert-butyl hydroperoxide (wherein the mass fraction of tert-butyl hydroperoxide is greater than 70%), continue stirring and heating to 50°C to prepare rare earth conversion solution.
  • Step 2.2 Submerge the surface-pretreated plate in step 1 in the rare earth conversion solution prepared in step 2.1, keep it at 50°C for 40 minutes, take out the cold air to dry it or dry it naturally, so that a rare earth conversion film is formed on the surface of the plate.
  • Step 3.1 Weigh 98 parts of ethanol, 1 part of heptadecylfluorodecyltrimethoxysilane, and 1 part of hydrophobic nano silicon dioxide (SiO 2 ) powder, ultrasonically disperse for 15 minutes, and mechanically stir for 2 hours to obtain Sol A.
  • Step 3.2 take 98 parts of sol A prepared in the above step 3.1, add 1.5 parts of hydrophobic nano-silica powder, 0.5 parts of nano-alumina (Al 2 O 3 ) powder, ultrasonically disperse for 15 minutes, and mechanically stir for 30 minutes to obtain a composite Material.
  • the hydrophobic nano-silica powder is obtained by treating fumed silica with dimethyldichlorosilane (CAS: 75-78-5). ⁇ 50nm; the shape of the particles included in the nano-alumina powder is irregular, and the particle size is 20-40nm.
  • Example 2-3 The difference between Examples 2-3 and Example 1 lies in that the composite material is prepared in Step 3. All the other are identical with embodiment 1.
  • step 3 prepares composite material and comprises:
  • Step 3.1 Weigh 99 parts of ethanol, 0.5 part of heptadecanylfluorodecyltrimethoxysilane, 0.5 part of hydrophobic nano Silica powder was ultrasonically dispersed for 15 minutes and mechanically stirred for 2 hours to obtain Sol A.
  • Step 3.2 Take 99.4 parts of sol A prepared in the above step 3.1, add 0.5 part of hydrophobic nano-silica powder and 0.1 part of nano-alumina powder, ultrasonically disperse for 15 minutes, and mechanically stir for 30 minutes to obtain a composite material.
  • step 3 prepares composite material and comprises:
  • Step 3.1 Weigh 96.5 parts of ethanol, 1.5 parts of heptadecylfluorodecyltrimethoxysilane, and 2 parts of hydrophobic nano-silica powder, ultrasonically disperse for 15 minutes, and mechanically stir for 2 hours to obtain Sol A.
  • Step 3.2 Take 97 parts of sol A prepared in the above step 3.1, add 2 parts of hydrophobic nano-silica powder and 1 part of nano-alumina powder, ultrasonically disperse for 15 minutes, and mechanically stir for 30 minutes to obtain a composite material.
  • Comparative Example 1 The difference between Comparative Example 1 and Example 1 lies in step 3, and the preparation of composite material in step 3 of Comparative Example 1 includes:
  • Step 3.1 Weigh 98 parts of ethanol, 1 part of heptadecafluorodecyltrimethoxysilane, and 1 part of hydrophobic nano-silica powder, ultrasonically disperse for 15 minutes, and mechanically stir for 2 hours to obtain Sol A.
  • Step 3.2 take 98 parts of sol A prepared in the above step 3.1, add 2 parts of hydrophobic nano-silica powder, ultrasonically disperse for 15 minutes, and mechanically stir for 30 minutes to obtain a composite material.
  • step 3 The difference between comparative example 2 and embodiment 1 is step 3, and the step 3 preparation composite material of comparative example 2 comprises:
  • Step 3.1 Weigh 98 parts of ethanol, 1 part of heptadecafluorodecyltrimethoxysilane, and 1 part of hydrophobic nano-silica powder, ultrasonically disperse for 15 minutes, and mechanically stir for 2 hours to obtain Sol A.
  • Step 3.2 take 98 parts of sol A prepared in the above step 3.1, add 2 parts of nano-alumina powder, ultrasonically disperse for 15 minutes, and mechanically stir for 30 minutes to obtain a composite material.
  • the test instrument used is a contact angle measuring instrument, which adopts the principle of optical imaging and uses image profile analysis to measure the contact angle of the sample.
  • the contact angle refers to the point where a drop of liquid drops on a solid horizontal plane, and the solid-liquid-gas three-phase junction point on the solid surface, when the two tangent lines of the gas-liquid interface and the solid-liquid interface sandwich the liquid phase into the corner.
  • the volume is generally about 1 ⁇ L
  • the droplet forms a droplet on the needle
  • the rotary knob moves the workbench up, so that the surface of the sample and the droplet Contact, and then move down the workbench, the droplet can be left on the sample.
  • the contact angle of this area is obtained through test software and data analysis.
  • the sample of each embodiment and the comparative example gets 5 different points to carry out the test and takes the average value, and records it as the contact angle of the sample of the embodiment and the comparative example.
  • test results of the above-mentioned contact angles show that the initial contact angles of the sample surfaces of Examples 1-3 and Comparative Examples 1-2 are all greater than 150°, showing a super-hydrophobic state, indicating that the various embodiments of the present disclosure and Comparative Examples are on the surface of the samples.
  • the formed hydrophobic coating has excellent hydrophobic properties.
  • the plate samples prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to salt spray test respectively.
  • the salt spray test refers to the test standard ASTM G85, and the acid salt spray test is carried out. Each sample is put into the salt spray box, and it is taken out at regular intervals to observe the surface corrosion points. After the acid salt spray test, each sample was taken out, the surface corrosion was observed and the time when corrosion spots appeared was recorded.
  • the present disclosure compares the samples of the salt spray test in the same period.
  • the present disclosure compares the samples of Comparative Example 1 and Comparative Example 2.
  • 48h salt spray test the sample surface topography of Comparative Example 1 and Comparative Example 2 is shown in Figure 7, wherein Figure 7 (a) is the sample surface topography of Comparative Example 1, and Figure 7 (b) is the sample surface topography of Comparative Example 2 Sample surface topography.
  • 96h salt spray test the sample surface topography of Comparative Example 1 and Comparative Example 2 is shown in Figure 8, wherein Figure 8 (a) is the sample surface topography of Comparative Example 1, and Figure 8 (b) is the sample surface topography of Comparative Example 2 Sample surface topography. It can be seen from Fig. 7 and Fig. 8 that the samples of Comparative Example 1 and Comparative Example 2 have the same salt spray resistance performance.
  • the present disclosure also compares the Example 1 and Comparative Example 1 samples.
  • 96 salt spray test the sample surface topography of embodiment 1 and comparative example 1 is as shown in Figure 9, wherein Fig. 9 (a) is the sample surface topography figure of embodiment 1, and Fig. 9 (b) is the sample surface topography of comparative example 1 Sample surface topography.
  • Fig. 9 in the 96h salt spray test, the rust spots on the sample surface of Example 1 are significantly less than that of Comparative Example 1.
  • the corrosion resistance of the sample of Example 1 is better than that of the sample of Comparative Example 1, indicating that the compounding of nano-alumina particles and hydrophobic fumed silica particles with different chemical compositions and particle shapes can significantly improve the corrosion resistance of the sample.
  • the corrosion resistance of the samples are better than that of the sample of Comparative Example 1, indicating that the compounding of nano-alumina particles and hydrophobic fumed silica particles with different chemical compositions and particle shapes can significantly improve the corrosion resistance of the sample.
  • the corrosion resistance of the samples 96

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Abstract

一种换热器，包括基体和覆设在基体的至少部分表面的涂层，涂层包括疏水涂层，疏水涂层包括低表面能硅烷类材料和分散在低表面能硅烷类材料中的填料，填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。不同形状的颗粒复配，增加疏水涂层对腐蚀介质的阻隔作用，提高换热器的耐腐蚀性能。一种复合材料包括低表面能硅烷类材料和上述填料。该复合材料能够在换热器表面形成防腐涂层，提高换热器的耐腐蚀性能。一种换热器的表面处理方法，包括：提供换热器，提供上述复合材料，将上述复合材料覆设于换热器的至少部分表面。本公开的表面处理方法能够提高换热器的耐腐蚀性能。

Description

换热器、用于换热器的复合材料和换热器的表面处理方法 技术领域
本公开涉及热交换装置，尤其涉及一种换热器、用于换热器的复合材料和换热器的表面处理方法。
背景技术
相关技术中，将疏水溶胶涂覆在换热器表面形成疏水涂层。疏水涂层使腐蚀性溶液在换热器表面具有较大的接触角、不易铺展，减小腐蚀性溶液与换热器表面的直接接触面积。此外，疏水涂层本身对腐蚀介质也具有一定的阻隔作用。因此，疏水涂层能够提高换热器的耐腐蚀性能。通常疏水溶胶形成的疏水涂层内部都不可避免地有一些微孔缺陷或者孔隙，为了增加疏水涂层的致密性，提高疏水涂层的阻隔作用，可以在疏水溶胶中添加填料，以增加疏水涂层的致密性。当前，大部分研究关注填料的含量对疏水涂层防腐效果的影响，但是较少关注组成填料所包含颗粒的形状对疏水涂层防腐效果的影响。
为了进一步提高换热器的耐腐蚀性能，相关技术还可以从颗粒形状着手，提高换热器的耐腐蚀性能。
发明内容
本公开的目的在于提供一种耐腐蚀性能好的换热器，相应地，本公开还提供一种用于换热器的复合材料，以及一种换热器的表面处理方法。
本公开提供一种换热器，其包括：
基体；以及
涂层，其覆设在所述基体的至少部分表面，所述涂层包括疏水涂层；
所述换热器具有用于流体流通的通道，所述疏水涂层包括低表面能硅烷类材料和分散在所述低表面能硅烷类材料中的填料，其中，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同。
本公开的疏水涂层包括低表面能硅烷类材料和填料。本公开疏水涂层中的填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。不同形状的 颗粒复配，有利于增加涂层的致密性，增加疏水涂层对腐蚀介质的阻隔作用，提高换热器的耐腐蚀性能。
本公开还提供一种用于换热器的复合材料，其包括：
低表面能硅烷类材料，所述低表面能硅烷类材料包括表面接枝有疏水基团的硅烷，所述疏水基团选自烃基、卤原子和硝基中的至少一种；以及
填料，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同。
本公开的复合材料在换热器表面形成含有两种形状的颗粒的疏水涂层，提高换热器的耐腐蚀性能。
本公开还提供一种换热器的表面处理方法，包括以下步骤：
提供换热器；
提供复合材料，所述复合材料包括低表面能硅烷类材料和填料，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同；
将所述复合材料覆设于所述换热器的至少部分表面，固化，形成覆设在所述换热器的至少部分表面的疏水涂层。
本公开的换热器的表面处理方法，能够在换热器的表面形成含有两种形状的颗粒的疏水涂层，提高换热器的耐腐蚀性能。
附图说明
图1为本公开一种实施方式中不规则形状颗粒的微观形貌示意图；
图2为本公开一种实施方式中三维枝状颗粒的微观形貌示意图；
图3为本公开一种实施方式中换热器的结构示意图；
图4为图3中的换热器的部分组件组装结构放大示意图；
图5为本公开一种实施方式中换热器基体表面疏水涂层的剖面示意图；
图6为本公开一种实施方式中换热器基体表面疏水涂层和稀土转化膜的剖面示意图；
图7为本公开48h盐雾测试中对比例1和对比例2的样品表面形貌；
图8为本公开96h盐雾测试中对比例1和对比例2的样品表面形貌；
图9为本公开96h盐雾测试中实施例1和对比例1的样品表面形貌。
具体实施方式
为了更好地理解本公开的技术方案，下面结合附图对本公开实施例进行详细描述。
应当明确，所描述的实施例仅仅是本公开一部分实施例，而不是全部的实施例。基于本公开中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本公开保护的范围。
当前市场上换热器产品表面的防腐涂层多为化学转化膜。例如，铝制换热器表面的防腐涂层多为铬盐钝化形成的化学转化膜(TCP)。由于六价铬剧毒致癌，国内外已严禁使用六价铬钝化涂层，当前市场采用三价铬代替六价铬进行铝制产品的表面防腐处理，但是三价铬对环境和人体的危害仍然不容忽视。基于此，研发适用于换热器的绿色环保涂料，通过涂覆涂料的方式在换热器表面形成防腐涂层，成为换热器表面防腐技术的重要发展方向。
一些相关技术在换热器表面涂覆疏水溶胶，疏水溶胶在换热器表面固化、形成疏水涂层。在固化过程中，由于疏水溶胶中的基团与金属基体表面的Me-OH缩合成键，并且疏水溶胶中的基团也相互交联成键、形成网状结构，因此形成的疏水涂层可以与换热器基体牢固结合。疏水涂层使腐蚀性溶液在换热器表面具有较大的接触角、不易铺展，减小腐蚀性溶液与换热器表面的直接接触面积。此外，疏水涂层本身对腐蚀介质也具有一定的物理阻隔或物理屏蔽作用，能够减少金属基体与外界物质(例如，氧气、水或其他腐蚀物质)的接触。如此，一方面减少或减缓酸、碱等对金属基体表面的化学腐蚀，另一方面由于金属基体接触的氧气和水减少，电极极化进程和去极化进程减缓，因而金属基体表面的电化学腐蚀也在一定程度上被减少或减缓。因此，疏水涂层能够提高换热器的耐腐蚀性能。
疏水涂层对耐腐蚀性能的提高主要取决于其疏水性能以及其内部微观结构。疏水涂层的疏水性能源自疏水涂层中的疏水基团，疏水涂层的内部微观结构则很大程度上受到疏水溶胶的交联度的影响。通常，交联度小的溶胶形成的涂层内部具有较多的孔隙，孔隙越多、涂层本身的阻隔作用就越小。随着交联度的增大，涂层密度、机械强度和硬度增加，涂层本身的阻隔作用也随之增大，但是过度交联会使得涂层脆性增加，导致涂层表面微裂纹增加甚至破裂。为了使疏水涂层能够牢固附着在金属基体，并且涂层内部不产生较多的微裂纹甚至破裂，疏水溶胶需要具有适当的交联度。通常疏水溶胶形成的疏水涂层内部都不可避免地有一些微孔缺陷或者孔隙，这些微孔缺陷或者孔隙容易成为腐蚀介质向金属基材扩散的路径。为此，可以在疏水溶胶中添加填料。
填料由许多的颗粒组成，组成填料的颗粒填充在疏水涂层的微孔缺陷或孔隙中，能够堵塞腐蚀介质的传输路径，阻碍腐蚀介质在疏水涂层中的传输和扩散，并且增加疏水涂层的致密性和厚度，从而提高疏水涂层本身对腐蚀物质的阻隔作用。当前，大部分研究重点关注疏水涂层中填料的含量对疏水涂层防腐效果的影响，但是却较少关注组成填料所包含颗粒的形状对疏水涂层防腐效果的影响。
本公开的第一方面提供一种换热器，换热器具有用于流体流通的通道，换热器包括基体和覆设在所述基体的至少部分表面的涂层，涂层包括疏水涂层，疏水涂层包括低表面能硅烷类材料和分散在低表面能硅烷类材料中的填料，填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。当然，在一些实施方式中，填料包括三种以上颗粒，所述三种以上颗粒中的至少两种颗粒的形状不同。
低表面能硅烷类材料指的是表面能低的硅烷类材料。当材料表面能较低时，能够表现出一定的疏水性能。
本公开的疏水涂层包括低表面能硅烷类材料和填料，填料所包括的颗粒填充在低表面能硅烷类材料的网状结构中，通过低表面能硅烷类材料与换热器基体牢固结合。低表面能硅烷类材料中的微孔缺陷或孔隙具有多种多样的形状。从孔隙填充的角度来说，颗粒与孔隙在形状上的匹配度越高，颗粒的填充效果越好。例如，对于不规则形状的孔隙，不规则形状颗粒在其中的填充能够实现较好的填充效果，对于规则形状的孔隙，则需要用与其匹配的颗粒填充能够实现较好的填充效果。颗粒形状的多样化有利于孔隙的填充。本公开疏水涂层中的填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。不同形状的颗粒复配，使颗粒在疏水涂层中具有良好的填充效果，有利于增加涂层的致密性，增加疏水涂层对腐蚀介质的阻隔作用，提高换热器的耐腐蚀性能。
填料的添加通常以添加一种和几种颗粒的形式进行，而非以添加一个或几个颗粒的形式进行。涂层中的每一种颗粒的数量以几十、几百、几千、几万、几千万、几亿、几亿万、甚至几兆计。例如，一种颗粒可以包括10、102、103、104、105、106、107、108、109、1010等数量的颗粒。也就是说，填料的添加关注的是颗粒的种类，而非颗粒的数量。因此，在讨论颗粒形状对疏水涂层的影响时，关注的并不是某一个或几个颗粒的形状，而是一种颗粒所包括的颗粒在形状上的共性以及两种以上颗粒在形状上的区别带来的影响。在本公开中，一种颗粒所包括的颗粒的化学组成和形状大致相同，一种颗粒对应具有一种化学组成和一种颗粒形状。
颗粒形状主要与制备工艺相关。常见的制备工艺有球磨法、气流磨、气雾化、水雾化、化学法等。采用不同制备工艺，所得到的颗粒形状也有所不同。例如，带材气流磨得到的粉体颗粒呈片状，通过水雾化或气雾化制备的粉体颗粒呈球状，采用沉淀法制备的二氧化硅粉体颗粒大致呈球状，气相法制备的二氧化硅粉体颗粒大致呈现三维枝状。受制备工艺条件的影响，一种颗粒所包括的所有颗粒的形状可能不会完全相同，在这种情况下，一种颗粒所对应的一种颗粒形状指的是该种颗粒所包括的大部分(例如数量占比50％、60％、70％、80％、90％、99％)的颗粒所具有的形状。例如，由于制备工艺的影响，一种化合物A颗粒所包括的99％的颗粒为球状，而剩余1％的颗粒为水滴状，我们仍然描述这种化合物A颗粒的形状为球状。也就是说，忽略由制备工艺造成的小部分数量的颗粒在形状上的偏差。
在一些实施方式中，两种颗粒中的一种的形状为不规则形状。
颗粒填充至低表面能硅烷类材料的网状结构中，并不是所有颗粒都能与其所填充的孔隙完全匹配，因此颗粒填充至孔隙中，在颗粒外表面可能还存在一些未被填充的缝隙，加上颗粒本身的强度、硬度和耐磨性等都要好于低表面能硅烷类材料，因而颗粒之间的空隙成为腐蚀介质穿透涂层到达换热器基体的主要路径。腐蚀介质在疏水涂层中的传输路径的曲折程度、长度等等很大程度上取决于颗粒的表面形貌，或者说颗粒的形状。
颗粒的形状可以分为规则形状和不规则形状。规则形状通常指的是在点、线或面的维度上具有一定数学规律的形状，例如球状、椭球状、棒状、针状、片状、柱状、六面体状、四面体状、树枝状、三维枝状等。规则形状颗粒通常能够通过其形状上具有规律的特征对其进行描述。而不规则形状则是相对于规则形状而言，不规则形状在点、线和面的维度上都没有明显数学规律的形状，例如图1所示。
相对于规则形状的颗粒而言，不规则形状颗粒更能够增加腐蚀介质的传输路径的曲折程度。因为无论是不规则形状颗粒之间，还是不规则形状颗粒与规则形状颗粒之间，空隙都呈不规则状。因此，不规则形状颗粒的引入，有利于阻碍腐蚀介质在疏水涂层中的穿透和扩散，延长腐蚀介质穿透疏水涂层到达换热器基体的时间，由此进一步提高疏水涂层对腐蚀介质的阻隔作用，提高换热器的耐腐蚀性能。此外，不规则形状颗粒还具有良好的抗滑移性，有利于保持疏水涂层的一致性和稳定性。
在一些实施方式中，两种颗粒的化学组成不相同。如前所述，颗粒的形状主要受制备工艺的影响。在一些情况下，可以用同一种材料、通过不同的制备工艺制备不同 种类的颗粒。例如，用氧化铝带材气流磨制备片状颗粒，用氧化铝气雾化制备球状颗粒，然后将片状氧化铝颗粒和球状氧化铝颗粒添加至疏水涂层中，实现不同形状的颗粒在涂层中的复配。在另一些情况下，还可以用不同的材料、通过不同的制备工艺制备不同种类的颗粒。例如，氧化铝不规则状颗粒与气相二氧化硅三维枝状颗粒复配。由于不同材料制备的颗粒具有不同的物理化学性能，例如强度、硬度、耐磨性等，添加至涂层中，能够对疏水涂层起到不同方面的加强，为了提高疏水涂层的综合性能，本公开还可以采用化学组成不同的颗粒。
在一些实施方式中，不规则形状颗粒选自氧化铝、氧化锌、氧化锆、氧化钛、氧化硅、氧化镧、氧化铈、氧化镨、氮化硼和硫酸钡中的一种。这些化合物具有良好的强度、硬度和耐磨性，作为填料添加至疏水涂层中，能够持久地增强疏水涂层的耐腐蚀性能。
在一些实施方式中，所述两种颗粒中的至少一种的形状为规则形状，规则形状选自球状、椭球状、棒状、针状、片状、柱状、六面体状、四面体状、树枝状、三维枝状中的一种。本公开还在疏水涂层中加入规则形状颗粒，增加颗粒形状的多样性。在一些实施方式中，三维枝状颗粒为气相二氧化硅颗粒。图2示意性地示出气相二氧化硅颗粒的形状。
在一些实施方式中，规则形状颗粒选自氧化铝、氧化锌、氧化锆、氧化钛、氧化硅、氧化镧、氧化铈、氧化镨、氮化硼、石墨烯、氧化石墨烯、碳纳米管和硫酸钡中的一种。
在一些实施方式中，所述两种颗粒的粒径范围为10～100nm。
本公开中，颗粒填充在低表面能硅烷类材料网状结构中，粒径过大或过小都会弱化涂层自身对腐蚀介质的阻隔作用：粒径过大的颗粒会增加涂层的内部缺陷；粒径过小的颗粒容易在涂层中团聚、不易分散，导致其不能均匀地填充在低表面能硅烷类材料网状结构的微孔或孔隙中。为了不影响换热器的换热性能，本公开换热器表面的疏水涂层较薄。相应地，本公开将颗粒的粒径范围选择在10～100nm，从而颗粒能够均匀地填充在低表面能硅烷类材料网状结构中，并且不会明显增加涂层的内部缺陷。
出于制备工艺的原因，一种颗粒的粒径通常在一个固定的粒径范围内。比如说，填料为二氧化铝颗粒，当描述二氧化铝颗粒的粒径范围为20～40nm时，指的是添加至疏水涂层中的二氧化铝颗粒的粒径均在20～40nm的范围内。相应地，一种颗粒还具有一个平均粒径。在本公开中，一种颗粒的平均粒径理论上指的是添加至疏水涂层中的 该种颗粒的粒径平均值。
在一些实施方式中，所述两种颗粒包括第一种颗粒和第二种颗粒，第一种颗粒的平均粒径是第二种颗粒的平均粒径的2～10倍。低表面能硅烷类材料中的孔隙的尺寸也是多样的，本公开采用具有不同平均粒径的颗粒，一方面能够提升颗粒对孔隙的填充效果，另一方面不同粒径的颗粒复配，也有利于增加涂层的致密性。在一些实施方式中，第一种颗粒是规则形状颗粒，第二种颗粒是不规则形状颗粒；或者，第一种颗粒是不规则形状颗粒，第二种颗粒是规则形状颗粒。在一些实施方式中，第一种颗粒和第二种颗粒在疏水涂层中含量的比例为1:1～1:5。
在一些实施方式中，所述两种颗粒均是在水中难溶或微溶的化合物。通常而言，在20℃水中，溶解度小于0.01g为难溶，溶解度大于0.01g且小于1g为微溶，溶解度大于1g小于10g为可溶，溶解度大于10g为易溶。难溶或微溶的颗粒能够在疏水涂层中长期稳定地存在，从而实现对疏水涂层防腐性能持久的提高。
在一些实施方式中，所述两种颗粒的电阻率均为109～1022Ω·cm。也就是说，颗粒由绝缘材料制备而成。如此，颗粒还能够利用绝缘特性减缓电化学腐蚀原电池中离子在阴极、阳极之间的转移，对阳极中金属阳离子的溢出和阴极产生的放电效应具有一定阻碍作用，即具有电阻效应，减少或减缓金属基体表面的电化学腐蚀。
在一些实施方式中，所述两种颗粒的至少一种的至少部分颗粒的表面接枝有疏水基团，疏水基团选自烃基、卤原子和硝基中的至少一种。在一些实施方式中，烃基可以是-CnH2n+1(n≥1)、-CH＝CH2、-C6H5；卤原子可以是-F、-Cl、-Br、-I、-At；硝基化学式为-NO2。可以对颗粒进行疏水处理，使其因表面接枝有疏水基团而具有一定的疏水性能。将具有一定疏水性能的颗粒填充至疏水涂层种，能够增加疏水涂层的疏水性。
在一些实施方式中，低表面能硅烷类材料包括表面接枝有疏水基团的硅烷，疏水基团选自烃基、卤原子和硝基中的至少一种。在一些实施方式中，烃基可以是-CnH2n+1(n≥1)、-CH＝CH2、-C6H5；卤原子可以是-F、-Cl、-Br、-I、-At；硝基化学式为-NO2。在一些实施方式中，低表面能硅烷类材料，例如可以选自十七氟癸基三乙氧基硅烷、十七氟癸基三甲氧基硅烷、十三氟辛基三乙氧基硅烷、十八烷基三甲氧基硅烷和十六烷基三甲氧基硅烷中的一种或多种。
在一些实施方式中，按质量份计，疏水涂层包括0.5～1.5份低表面能硅烷类材料的含量是和的0.1～5份填料。
本文中，除非另有说明，否则所涉及的百分数、比例或份数按照质量计。其中， “质量份”指多个组分的质量比例关系的基本计量单位，1份可表示任意的单位质量，例如1份可以表示为1g，可以表示1.68g，也可以表示为5g等。
在含有填料的疏水涂层中，填料含量或者填料与低表面能硅烷类材料的配比是影响耐腐蚀性能的关键因素。填料含量太小无法使涂层的防腐效果达到最佳，填料含量太大，则会导致填料与低表面能硅烷类材料的相容性下降，填料在疏水涂层中分散不均，最终造成疏水涂层性能均一性差，增加疏水涂层内部的缺陷和裂纹，甚至导致涂层破裂，而且还会降低涂层的疏水性能。在本公开的配比下，既能够有效保持疏水涂层良好的疏水性能，还能够明显提高疏水涂层的阻隔作用，由此使疏水涂层提高换热器的表面耐腐蚀性能的作用达到较佳水平。
在一些实施方式中，疏水涂层与水的静态接触角大于150°，疏水涂层的水滴滚动角小于5°。在本公开的低表面能硅烷类材料和填料的配比下，疏水涂层具有较好的疏水性能。
在一些实施方式中，基体的至少部分表面覆设有稀土转化膜，稀土转化膜包括稀土化合物，稀土转化膜的至少部分位于基体和疏水涂层之间。稀土转化膜位于基体和疏水涂层之间指的是，稀土转化膜的一面与基体直接接触，稀土转化膜的另一面与疏水涂层直接接触，疏水涂层相对稀土转化膜远离基体，稀土转化膜夹于换热器基体和疏水涂层之间，疏水涂层通过稀土转化膜附着在换热器基体表面。在一些情况下，换热器基体表面覆设的疏水涂层可以与换热器基体直接接触；或者，该疏水涂层与换热器基体之间还有稀土转化膜；或者，该疏水涂层的一部分与换热器基体直接接触，疏水涂层的另一部分与换热器基体之间还有稀土转化膜。在一些情况下，稀土转化膜可以全部位于换热器基体与疏水涂层之间；或者，一部分稀土转化膜位于换热器基体和疏水涂层之间，另一部分稀土转化膜的一面与换热器基体直接接触、另一面暴露在外界环境中，也就是另一部分稀土转化膜之上不再覆设有疏水涂层，换热器的一部分表面仅覆设有稀土转化膜。稀土转化膜中的稀土化合物可以进一步提高换热器的耐腐蚀性能。
在一些实施方式中，稀土化合物包括稀土氧化物和/或稀土氢氧化物。例如，稀土化合物可以是氧化铈(CeO2)、三氧化二铈(Ce2O3)、氢氧化铈(Ce(OH)4)等。同样地，稀土化合物也可以是其他稀土元素，例如La、Pr、Nd、Pm、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Sc、Y的化合物。
在一些实施方式中，换热器包括集流管、翅片和多根换热管，换热管与集流管相 固定，换热管的内腔与集流管的内腔相连通，翅片的至少部分固定于相邻的两根换热管之间，基体包括集流管、换热管和翅片中的至少一者的基体。也就是说，换热器是微通道换热器。疏水涂层，或者疏水涂层和稀土转化膜，涂覆在集流管、换热管和翅片中的至少一者的至少部分表面。
下面以微通道换热器为例，对本公开的换热器进行示例性说明。
如图3和图4所示，本公开提供一种换热器100，换热器100包括集流管11、多个换热管12以及多个翅片13。在换热器100中，多个换热管12均与集流管11相固定，换热管12设有多个供制冷剂流通的通道122，并且换热管12的多个通道122均与集流管11的内腔连通，翅片13的至少部分固定于相邻的两个换热管12之间。集流管11上设有与其内腔相连通的流体进口101和流体出口102，从而方便流体进入换热器。
多个换热管12沿着集流管11的长度方向布置，集流管11的长度方向可参考图3或图4中的X方向。换热管12为纵向延伸的管状结构，换热管12的长度方向可参考图3或图4中的Y方向，换热管12的宽度方向可参考图4中的D方向。换热管12的宽度方向的尺寸大于换热管12的厚度方向的尺寸，换热管12的厚度方向与集流管11的长度方向大致重合。并且，换热管12的宽度方向与集流管11的长度方向不共向。在图4中，换热管12的宽度方向(D方向)与集流管11的长度方向(X方向)大致呈垂直关系。
在图3中，集流管11的数量为2个，换热管12长度方向的两端分别插入至该两个集流管11的内腔。这种类型的换热器业内也常称为单排换热器，在一些其他实施方式中，集流管11的数量可以为1个或者超过2个以上。相应的，换热管和翅片的数量也根据实际产品需要进行设定。
在一些实施方式中，如图4所示，翅片13在沿换热管12的长度方向(Y方向)上呈波形。翅片13包括沿换热管12的长度方向布置的多个翅片单元131，多个翅片单元131沿换热管12的长度方向依次相连，相邻的两个翅片单元131相连接的位置处形成翅片13对应的波形结构中的波峰或波谷，且翅片13在相邻的两个翅片单元131相连接的位置处与换热管12相固定。在装配时，集流管11、翅片13以及换热管12等部件可以预先组装在一起，经过钎焊工艺使得集流管11与换热管12固定，翅片13固定在相邻的两个换热管之间。
换热器100包括基体100-1和覆设在基体100-1的至少部分表面的疏水涂层14， 基体100-1是集流管11、换热管12和翅片13中的至少一者的基体。
图5为本公开一个实施例中换热器基体表面的剖面示意图。如图5所示，换热器基体100-1表面覆设有疏水涂层14，疏水涂层包括低表面能硅烷类材料141和分散在低表面能硅烷类材料中两种颗粒，其中一种颗粒的形状为不规则形状，另一种颗粒的形状三维枝状，不规则形状颗粒142和三维枝状颗粒143混合填充在低表面能硅烷类材料141中。图5中用R1和R2示出腐蚀介质在疏水涂层中的传输路径，从图中可以看到，不规则形状颗粒和三维枝状颗粒的复配使得腐蚀介质穿透疏水涂层的路径更加曲折，由此能够提升疏水涂层对腐蚀介质的阻隔作用。
图6为本公开另一个实施例的换热器基体表面的剖面示意图。如图6所示，换热器基体100-1表面覆设有稀土转化膜15，稀土转化膜15包括稀土化合物151(以三角形示出)，稀土转化膜15位于换热器基体100-1和疏水涂层14之间。
在另一些实施方式中，本公开的换热器还可以是板式换热器、管片式换热器、管壳式换热器、圆管翅片式换热器、水冷板、直冷板等用于制冷剂或者冷却液流动的换热器。也就是说，本公开的疏水涂层，或者疏水涂层和稀土转化膜不仅可以用于为通道换热器，还可以用于板式换热器、管片式换热器、管壳式换热器、圆管翅片式换热器、水冷板、直冷板等其他换热器的表面防腐处理。
本公开的第二方面提供一种换热器的表面处理方法，依次包括：
步骤S11、提供换热器；
步骤S21、提供复合材料，复合材料包括溶剂、低表面能硅烷类材料和填料，填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同；
步骤S31、将复合材料覆设于S11所提供的换热器的至少部分表面，固化，形成覆设在换热器的至少部分表面的疏水涂层。
低表面能硅烷类材料的特性和种类，填料颗粒的形状、粒径范围、化学组成和种类等参考前文，在此不再赘述。
在一些实施方式中，步骤S11提供的换热器的基体经过表面喷砂处理。具体地，在一些实施方式中，表面喷砂处理具体包括：将换热器的基体表面进行100～200目的白刚玉喷砂处理，喷砂角度30°～60°，喷枪与工件距离30～60mm，喷砂次数大于或等于1，然后用醇或水对换热器表面进行超声清洗或喷洗，晾干或在35℃～50℃下烘干。喷砂处理可以增加换热器表面的粗糙度，从而使疏水涂层在换热器基体表面的附着更加稳固。在一些实施方式中，换热器基体表面的粗糙度Ra为0.5μm～10μm，在一些实 施方式中，换热器基体表面的粗糙度Ra为1μm～3μm。例如，可以为1μm、1.2μm、1.4μm、1.6μm、1.8μm、2.0μm、2.2μm、2.4μm、2.6μm、2.8μm、3μm等等。
在一些实施方式中，在步骤S31中，将复合材料覆设于换热器的至少部分表面的方式包括但不限于浸涂、喷涂、刷涂、淋涂或辊涂中的至少一种。
在一些实施方式中，在步骤S31中，固化的方式，例如可以在烘箱中烘干。在一些实施方式中，固化温度为60～180℃。在一些实施方式中，固化时间为5～35min。
在一些实施方式中，在步骤S31之前、步骤S11之后还包括：步骤S41、在换热器的基体表面形成稀土转化膜。对于步骤S41和步骤S21的先后顺序不做限制，步骤S41可以在步骤S21之前，也可以在步骤S21之后。
在一些实施方式中，步骤S41包括：制备稀土转化溶液，将换热器浸没在稀土转化溶液中，将换热器取出，然后对换热器表面进行干燥。在另一些实施例，也可以将稀土转化液浸涂、喷涂、刷涂、淋涂或辊涂在换热器表面。
在一些实施方式中，稀土转化液包括稀土原料、氧化剂和水。
在一些实施方式中，稀土转化液包括1～3份稀土原料、92.5～97.5份水和1.5～4.5份氧化剂。
在一些实施方式中，稀土转化液的制备方法包括：将稀土原料溶解于水中，然后加入氧化剂，制得稀土转化液。
在一些实施方式中，稀土转化液的制备方法可以包括：按质量份计，将1～3份的稀土原料溶于92.5～97.5份的去离子水中，混合处理得到中间液；将中间液加热至45℃～55℃，再向体系中加入1.5～4.5份的氧化剂，继续混合得到稀土转化液。
上述稀土原料是可以提供稀土元素的原料，如能提供铈(Ce)元素的原料。在一些实施方式中，稀土原料包括但不限于，六水合硝酸铈、无水硝酸铈、氯化铈及其多水化合物、硫酸铈及其多水化合物、醋酸铈及其多水化合物中的一种或至少两种的组合。上述氯化铈及其多水化合物是无水氯化铈、氯化铈的多水化合物如七水氯化铈或八水合氯化铈等。类似的，上述硫酸铈及其多水化合物是无水硫酸铈、硫酸铈的多水化合物如四水硫酸铈；醋酸铈及其多水化合物是无水醋酸铈、醋酸铈的多水化合物如三水醋酸铈或四水醋酸铈等。
在一些实施方式中，氧化剂包括但不限于，过氧化氢、高氯酸钠和叔丁基过氧化氢中的至少一种。例如，氧化剂可以为过氧化氢水溶液(过氧化氢的质量浓度约为27.5wt.％～30wt.％)，或者氧化剂可以为高氯酸钠，或者氧化剂可以为叔丁基过氧化氢水溶 液或者是叔丁基过氧化氢的正丁醇溶液(叔丁基过氧化氢的质量浓度不低于60wt.％)。
本公开的第三方面还提供一种用于换热器的复合材料，复合材料包括溶剂、低表面能硅烷类材料和填料，填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。该复合材料能够在换热器表面形成含有两种形状的颗粒的防腐涂层，提高换热器的耐腐蚀性能。
在一些实施方式中，溶剂选自乙醇、甲醇和异丙醇中的至少一种。
低表面能硅烷类材料的特性和种类，填料颗粒的形状、粒径范围、化学组成和种类等参考前文，在此不再赘述。
在一些实施方式中，按质量份计，复合材料包括93.5～99.4份溶剂、0.5～1.5份低表面能硅烷类材料和0.1～5份填料，填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。
在一些实施方式中，步骤S21所提供的复合材料通过自制得到。
本公开的第四方面提供一种复合材料的制备方法，复合材料的制备方法包括：将溶剂、低表面能硅烷类材料和填料混合，得到复合材料，其中填料包括两种颗粒，两种颗粒中的每一种具有一种形状，两种颗粒的形状不同。
在本公开中，混合可以是机械搅拌、超声分散或其他方式的混合；制备原料的加入可以一次性全部加入溶剂，也可以分两次或多次加入溶剂，本公开对混合方式、加料次序、加料方式和加料次数不作限制。在一些实施方式中，两种颗粒中的至少一种分两次或多次加入溶剂。如此，有利于填料在复合材料中的分散，从而使填料均匀地分散在低表面能硅烷类材料所形成的网状结构中。
为便于理解本发明，本公开进行了多组实验验证。下面结合具体实施例、对比例，对本发明作进一步说明。为了便于进行性能测试，采用板片代替换热器进行样品制备。也即，采用与换热器的材质相同的板片，并在板片上涂覆相关涂料形成涂层进行测试。实际制备过程中，换热器的表面处理可以采用与本实施例板片的表面处理相同的步骤。
实施例1
步骤1、表面预处理
采用120目白刚玉对板片进行喷砂处理，喷枪与待涂覆位置所呈角度在45℃左右，喷枪与待涂覆位置距离50mm，喷砂1遍，然后用无水乙醇对板片喷洗干净，40℃烘干备用。
步骤2、形成稀土转化膜
步骤2.1、称取1份六水合硝酸铈于烧杯中，加入95.1份去离子水，机械搅拌至固体全溶，溶液为无色透明。将该溶液水浴加热至50℃，加入2.4份过氧化氢叔丁基的正丁醇溶液(其中，过氧化氢叔丁基的质量分数大于70％)，继续搅拌加热至50℃，制备稀土转化溶液。
步骤2.2、将经过步骤1表面预处理的板片浸没在步骤2.1制备的稀土转化溶液中，50℃静置保温40min，取出冷风吹干或自然晾干，如此在板片表面形成稀土转化膜。
其中，稀土转化膜形成过程主要方程式为：
Al→Al3++3e-；
O2+2H2O+4e-→4OH-；
Ce3++3OH-→Ce(OH)3；
2Ce(OH)3→Ce2O3+3H2O。
步骤3、制备复合材料
步骤3.1、称取98份乙醇，1份十七氟癸基三甲氧基硅烷，1份疏水性纳米二氧化硅(SiO2)粉体，超声分散15min，机械搅拌2h后得到溶胶A。
步骤3.2、取上述步骤3.1制备的溶胶A 98份，加入1.5份疏水性纳米二氧化硅粉体、0.5份纳米氧化铝(Al2O3)粉体，超声分散15min，机械搅拌30min，得到复合材料。
其中，疏水性纳米二氧化硅粉体是通过二甲基二氯硅烷(CAS：75-78-5)处理气相二氧化硅得到，气相二氧化硅颗粒的形状为三维枝状，粒径为5～50nm；纳米二氧化铝粉体所包括的颗粒的形状为不规则形状，粒径为20～40nm。
步骤4、涂覆板片
将经过步骤2、表面覆设有稀土转化膜的板片整体浸入步骤3制备的复合材料中，浸涂时长2min，浸涂完毕后放入烘箱中，在120℃下固化20min，得到带有稀土转化膜和疏水涂层的板片。
实施例2～3
实施例2～3与实施例1不同之处主要在于步骤3制备复合材料。其余均与实施例1相同。
实施例2中，步骤3制备复合材料包括：
步骤3.1、称取99份乙醇，0.5份十七氟癸基三甲氧基硅烷，0.5份疏水性纳米 二氧化硅粉体，超声分散15min，机械搅拌2h后得到溶胶A。
步骤3.2、取上述步骤3.1制备的溶胶A 99.4份，加入0.5份疏水性纳米二氧化硅粉体、0.1份纳米氧化铝粉体，超声分散15min，机械搅拌30min，得到复合材料。
实施例3中，步骤3制备复合材料包括：
步骤3.1、称取96.5份乙醇，1.5份十七氟癸基三甲氧基硅烷，2份疏水性纳米二氧化硅粉体，超声分散15min，机械搅拌2h后得到溶胶A。
步骤3.2、取上述步骤3.1制备的溶胶A 97份，加入2份疏水性纳米二氧化硅粉体、1份纳米氧化铝粉体，超声分散15min，机械搅拌30min，得到复合材料。
对比例1
对比例1与实施例1的不同之处在于步骤3，对比例1的步骤3制备复合材料包括：
步骤3.1、称取98份乙醇，1份十七氟癸基三甲氧基硅烷，1份疏水性纳米二氧化硅粉体，超声分散15min，机械搅拌2h后得到溶胶A。
步骤3.2、取上述步骤3.1制备的溶胶A 98份，加入2份疏水性纳米二氧化硅粉体，超声分散15min，机械搅拌30min，得到复合材料。
其余均与实施例1相同。
对比例2
对比例2与实施例1的不同之处在于步骤3，对比例2的步骤3制备复合材料包括：
步骤3.1、称取98份乙醇，1份十七氟癸基三甲氧基硅烷，1份疏水性纳米二氧化硅粉体，超声分散15min，机械搅拌2h后得到溶胶A。
步骤3.2、取上述步骤3.1制备的溶胶A 98份，加入2份纳米氧化铝粉体，超声分散15min，机械搅拌30min，得到复合材料。
其余均与实施例1相同。
性能测试
1.疏水性能测试(接触角测试)
所用测试仪器为接触角测量仪，其采用光学成像原理，采用图像轮廓分析方式测量样品接触角。接触角是指在一固体水平平面上滴一滴液滴，固体表面上的固-液-气三相交界点处，其气-液界面和固-液界面两切线把液相夹在其中时所成的角。
测试时，打开接触角测量仪和与之相连的电脑，打开测试软件。
把试样放在水平工作台上，利用微量进样器调整液滴的量，体积一般为1μL左右，液滴在针头形成液滴，旋转旋钮使工作台上移，让试样表面与液滴接触，再下移工作台，试样上即可留下液滴。
通过测试软件进行测试和数据分析，得到这一区域的接触角。每一实施例和对比例的试样取5个不同的点进行测试后取平均值，记为该实施例和对比例试样的接触角。
经过上述接触角的测试结果表明，实施例1～3和对比例1～2的试样表面初始接触角均大于150°，呈现超疏水态，说明本公开的各个实施例以及对比例在样品表面所形成的疏水涂层具有优异的疏水性能。
2、耐腐蚀性测试(盐雾测试)
将实施例1～3和对比例1～2制得的板片试样分别进行盐雾测试。其中，盐雾测试参照测试标准ASTM G85，进行酸性盐雾测试，将各试样放进盐雾箱，每隔一定时间取出观察表面腐蚀点情况。经过酸性盐雾测试后，取出各样品，观察其表面腐蚀情况并记录出现腐蚀点的时间。
受盐雾箱状态和样品摆放位置影响，即使相同配方的样品，在不同批次盐雾试验结果也相差较大。因此，为了更好地对比不同配方制备的板片的耐腐蚀性能，本公开对同期盐雾试验的样品进行对比。
本公开将对比例1与对比例2的样品进行对比。48h盐雾测试，对比例1和对比例2的样品表面形貌如图7所示，其中图7(a)为对比例1的样品表面形貌图，图7(b)为对比例2的样品表面形貌图。96h盐雾测试，对比例1和对比例2的样品表面形貌如图8所示，其中图8(a)为对比例1的样品表面形貌图，图8(b)为对比例2的样品表面形貌图。从图7和图8可以看出，对比例1和对比例2样品的耐盐雾性能相当。
本公开还将实施例1与对比例1的样品进行对比。96盐雾测试，实施例1和对比例1的样品表面形貌如图9所示，其中图9(a)为实施例1的样品表面形貌图，图9(b)为对比例1的样品表面形貌图。从图9看到，在96h盐雾测试中，实施例1样品表面的锈点明显少于对比例1。由此可见，实施例1的样品的耐腐蚀性能要优于对比例1的样品，说明化学组成和颗粒形状均不相同的纳米二氧化铝颗粒和疏水性气相二氧化硅颗粒复配能够明显提高样品的耐腐蚀性能。
尽管已经示出和描述了本公开的实施例，本领域的普通技术人员可以理解：在不脱离本公开的原理和宗旨的情况下可以对这些实施例进行多种变化、修改、替换和变 型，本公开的范围由权利要求及其等同物限定。

Claims (20)

  1. 一种换热器，其包括：
    基体；以及
    涂层，其覆设在所述基体的至少部分表面，所述涂层包括疏水涂层；
    所述换热器具有用于流体流通的通道，所述疏水涂层包括低表面能硅烷类材料和分散在所述低表面能硅烷类材料中的填料，其中，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同。
  2. 根据权利要求1所述的换热器，其中，所述两种颗粒中的至少一种的形状为规则形状，所述规则形状选自球状、椭球状、棒状、针状、片状、柱状、六面体状、四面体状、树枝状、三维枝状中的一种。
  3. 根据权利要求2所述的换热器，其中，所述两种颗粒中的一种具有不规则形状，所述两种颗粒中的另一种具有规则形状；
    所述不规则形状颗粒选自氧化铝、氧化锌、氧化锆、氧化钛、氧化硅、氧化镧、氧化铈、氧化镨、氮化硼和硫酸钡中的一种；
    所述规则形状颗粒选自氧化铝、氧化锌、氧化锆、氧化钛、氧化硅、氧化镧、氧化铈、氧化镨、氮化硼、石墨烯、氧化石墨烯、碳纳米管和硫酸钡中的一种。
  4. 根据权利要求3所述的换热器，其中，所述不规则形状颗粒与所述规则形状颗粒在所述疏水涂层中含量的比例为1:1～1:5。
  5. 根据权利要求1所述的换热器，其中，所述两种颗粒的粒径范围均为10～100nm。
  6. 根据权利要求1所述的换热器，其中，所述两种颗粒的至少一种的至少部分颗粒的表面接枝有疏水基团，所述疏水基团选自烃基、卤原子和硝基中的至少一种。
  7. 根据权利要求1所述的换热器，其中，所述低表面能硅烷类材料包括表面接枝有疏水基团的硅烷，所述疏水基团选自烃基、卤原子和硝基中的至少一种。
  8. 根据权利要求1所述的换热器，其中，所述涂层包括覆设在所述基体的至少部分表面的稀土转化膜，所述稀土转化膜包括稀土化合物，所述稀土转化膜的至少部分位于所述基体和所述疏水涂层之间。
  9. 根据权利要求1～8任一项所述的换热器，其中，所述换热器包括集流管、翅片 和多根换热管，所述换热管与所述集流管相固定，所述换热管的内腔与所述集流管的内腔相连通，所述翅片的至少部分固定于相邻的两根换热管之间，所述基体包括集流管、所述换热管和所述翅片中的至少一者的基体。
  10. 一种用于换热器的复合材料，其包括：
    低表面能硅烷类材料，所述低表面能硅烷类材料包括表面接枝有疏水基团的硅烷，所述疏水基团选自烃基、卤原子和硝基中的至少一种；以及
    填料，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同。
  11. 根据权利要求10所述的复合材料，其中，所述两种颗粒中的至少一种的形状为规则形状，所述规则形状选自球状、椭球状、棒状、针状、片状、柱状、六面体状、四面体状、树枝状、三维枝状中的一种。
  12. 根据权利要求10所述的复合材料，其中，所述两种颗粒的粒径范围为10～100nm。
  13. 根据权利要求10所述的复合材料，其中，所述两种颗粒的至少一种的至少部分颗粒的表面接枝有疏水基团，所述疏水基团选自烃基、卤原子和硝基中的至少一种。
  14. 根据权利要求10所述的复合材料，其中，按质量份计，所述复合材料包括93.5～99.4份溶剂、0.5～1.5份所述低表面能硅烷类材料和0.1～5份所述填料。
  15. 一种换热器的表面处理方法，包括以下步骤：
    提供换热器；
    提供复合材料，所述复合材料包括低表面能硅烷类材料和填料，所述填料包括两种颗粒，所述两种颗粒中的每一种具有一种形状，所述两种颗粒的形状不同；
    将所述复合材料覆设于所述换热器的至少部分表面，固化，形成覆设在所述换热器的至少部分表面的疏水涂层。
  16. 根据权利要求15所述的表面处理方法，其中，所述换热器包括基体，在将所述复合材料覆设于所述换热器的至少部分表面之前，包括以下步骤：
    在所述基体的表面形成稀土转化膜。
  17. 根据权利要求16所述的表面处理方法，其中，在所述基体的表面形成稀土转化膜，包括以下步骤：
    制备稀土转化溶液，将所述换热器浸没在所述稀土转化溶液中，将所述换热器取出，然后对所述换热器表面进行干燥。
  18. 根据权利要求17所述的表面处理方法，其中，所述制备稀土转化溶液，包括以下步骤：
    按质量份计，将1～3份的稀土原料溶于92.5～97.5份的去离子水中，混合处理得到中间液；将所述中间液加热至45℃～55℃，再加入1.5～4.5份的氧化剂，继续混合得到所述稀土转化溶液。
  19. 根据权利要求18所述的表面处理方法，其中，所述稀土原料选自六水合硝酸铈、无水硝酸铈、氯化铈及其多水化合物、硫酸铈及其多水化合物、醋酸铈及其多水化合物中的一种或至少两种的组合，所述氧化剂选自过氧化氢、高氯酸钠和叔丁基过氧化氢中的至少一种。
  20. 根据权利要求16所述的表面处理方法，其中，在所述基体的表面形成稀土转化膜之前，包括以下步骤：
    对所述基体的表面进行喷砂处理，所述喷砂处理采用100～200目的磨料。
PCT/CN2023/072969 2022-01-27 2023-01-18 换热器、用于换热器的复合材料和换热器的表面处理方法 WO2023143324A1 (zh)

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