JP2004333115A - Heat exchanger, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger having excellent corrosion resistance, and a method for manufacturing the same. <P>SOLUTION: A flat hollow body having a fluid passage inside is formed by brazing circumferential edge parts of two plates 2 as heat exchanger component members with each other. Each plate 2 comprises a core layer 21 of aluminum or aluminum alloy, and Al-Si alloy layers 22 covering both surfaces of the core layer 21. In the core layer 21, Si from the Al-Si alloy layer 22 is diffused. The Al-Si alloy layer 22 has a part including Si by 1.65 mass% or less. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat exchanger and a method for manufacturing the same, and more particularly, to a method for reducing the CO concentration in a fuel gas (hydrogen gas) generated by a reformer in a fuel cell system used for a fuel cell vehicle or a cogeneration system, for example. And a method for manufacturing the same.

  In this specification and the claims, the “fluoride layer” refers to a layer substantially consisting of fluoride.

  The fuel cell system uses a reformer to generate a hydrogen gas containing a relatively large amount of CO using a lower hydrocarbon gas such as methane, propane, butane, or gasoline or methanol as a fuel. Is sequentially reduced by a plurality of heat exchangers to obtain high-purity hydrogen gas, and the high-purity hydrogen gas is used to generate power by a fuel cell.

  Generally, a heat exchanger for reducing CO in a fuel cell system is formed using stainless steel in consideration of heat resistance and corrosion resistance. The temperature is about 130 to 140 ° C., and it is considered to be formed from pure aluminum or an aluminum alloy for the purpose of cost reduction and weight reduction. However, the fuel hydrogen gas generated by the reformer contains an acidic gas component, and the drain water generated in the CO-reducing heat exchanger has an acidity of pH 3 to 4, so that the surface treatment is excellent in corrosion resistance. Need to be applied.

  Conventionally, as a surface treatment method for imparting excellent corrosion resistance to pure aluminum or an aluminum alloy material, there is known a method in which a surface of pure aluminum or an aluminum alloy material is subjected to a fluoridation treatment with fluorine gas to form a fluorinated passive film. (For example, see Patent Document 1).

  By the way, a pure aluminum or aluminum alloy heat exchanger for reducing CO is composed of a plurality of parallel flat hollow bodies having a fluid passage therein, and an aluminum brazed to the flat hollow bodies arranged between adjacent flat hollow bodies. An alloy corrugated fin, wherein the flat hollow body is composed of two plates whose peripheral edges are brazed, and a swelling fluid passage between the two plates and a swelling fluid passage connected to both ends thereof. The header forming portion is provided, and the water containing long life coolant flows through the fluid passage in the flat hollow body, and the fuel hydrogen gas generated by the reformer flows through the gap between the adjacent flat hollow bodies. ing.

  Such a heat exchanger for reducing CO includes, for example, a bulging portion for forming a fluid passage using a brazing sheet in which both surfaces of a core material made of JIS A3003 alloy are covered with a cladding material made of JIS A4004 alloy, and a fluid passage. A plate having a header forming bulge portion deeper than the forming bulge portion and connected to both ends of the fluid passage forming bulge portion is formed. Two plates face each other with openings of both bulge portions facing each other. A plurality of the plate pairs formed as described above are stacked so that the bottom wall outer surfaces of the header forming bulging portions abut against each other, and JIS A3003 is provided between the portions corresponding to the fluid passage forming bulging portions in the adjacent plate pairs. Placing a corrugated fin made of an alloy bare material, and brazing the peripheral edges of both plates constituting the plate pair to form a flat hollow body, It is prepared by the corrugated fins brazed to the flat hollow body. Then, after brazing, the outer peripheral surface of the flat hollow body is heated by heating the brazed body of the flat hollow body and the fins in an atmosphere containing a fluoridation gas, as described in Patent Document 1. And forming a fluoride layer on the surface of the fin.

However, in the above-described manufacturing method, an Al—Si alloy layer having a Si content of 10 wt% is formed on the surface layer of the outer peripheral surface of the flat hollow body in the heat exchanger before the fluoride layer is formed. A eutectic of Al and Si (Al-12 wt% Si eutectic) exists in the Al-Si alloy layer. Therefore, during the fluorination treatment in the subsequent step, Si and F react to form a compound called SiF ₄ , which evaporates, and a fluoride layer having a required thickness on the outer peripheral surface of the flat hollow body is uniformly formed. No longer formed. The fuel hydrogen gas containing the acidic gas component generated by the reformer flows through the gap between the adjacent flat hollow bodies to generate drain water having a pH of 3 to 4 and the drain water generates the outer peripheral surface of the flat hollow body. However, there is a problem that corrosion proceeds to the JIS A3003 alloy constituting the core layer of the flat hollow body. Corrosion of the outer peripheral surface of the flat hollow body proceeds from the remaining Al-Si 12 wt% eutectic crystal grain boundary.
JP-A-2-263972 (Claims)

  An object of the present invention is to solve the above problems and to provide a heat exchanger excellent in corrosion resistance and a method for manufacturing the same.

  The present invention has the following aspects to solve the above problems.

  1) A heat exchanger component whose surface is covered with an Al-Si alloy layer and a fluoride layer is formed on the surface of the Al-Si alloy layer, and the heat exchanger component Al-Si A heat exchanger in which the alloy layer has a portion having a Si content of 1.65% by mass or less.

  2) The heat exchanger as described in 1) above, wherein the thickness of the fluoride layer is 2 nm to 10 μm.

  3) The heat exchanger as described in 1) or 2) above, wherein the fluoride layer is made of a fluoride produced by subjecting the surface of the Al—Si alloy layer of the heat exchanger component to fluorination treatment.

  4) An anodic oxide film is formed on the surface of the Al-Si alloy layer of the heat exchanger component, a nickel-containing plating layer is formed on the surface of the anodic oxide film, and a fluoride layer is formed on the surface of the plating layer. The heat exchanger according to the above 1) or 2), wherein the heat exchanger is formed, and the fluoride layer is made of a fluoride generated by fluorinating the surface of the plating layer.

  5) On the surface of the fluoride layer, at least one laminated group composed of a nickel-containing plating layer and a fluoride layer made of fluoride generated by subjecting the surface of the plating layer to fluorination is formed. The heat exchanger according to any one of 1) to 4) above.

  6) The heat exchanger component is composed of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and Si from the Al-Si alloy layer is diffused into the core layer, The heat exchanger according to any one of the above 1) to 5), wherein each Al-Si alloy layer has a portion having a Si content of 1.65% by mass or less.

  7) The heat exchanger according to the above 6), wherein at least one surface of the heat exchanger constituent member is exposed to a fluid containing an acidic component.

  8) The heat exchanger constituent member has a portion composed of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and any one of the Al-Si alloy layers An intermediate layer made of pure aluminum is formed between the core layer and the intermediate layer, Si from the Al-Si alloy layer is diffused into the intermediate layer, and the Al-Si alloy layer on the side where the intermediate layer is formed is The heat exchanger according to any one of the above 1) to 5), having a portion having a Si content of 1.65% by mass or less.

  9) The heat exchanger component is composed of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both sides of the core layer. An intermediate layer made of aluminum is formed, Si from the Al-Si alloy layer is diffused into each intermediate layer, and each Al-Si alloy layer removes a portion having a Si content of 1.65% by mass or less. The heat exchanger according to any one of 1) to 5) above.

  10) The heat exchanger as described in 8) or 9) above, wherein a total of 0.1 to 0.25 mass% of Zr and / or Mg is added to pure aluminum constituting the intermediate layer.

  11) The heat exchanger according to any one of 8) to 10) above, wherein the ratio of the thickness of the intermediate layer is 5 to 25% with respect to 100% of the total thickness of the heat exchanger constituent members.

  12) The heat exchanger according to any one of 8) to 11) above, wherein the surface of the heat exchanger component on the side where the intermediate layer is present is exposed to a fluid containing an acidic component.

  13) a plurality of parallel flat hollow bodies having a fluid passage therein, and fins disposed between adjacent flat hollow bodies and fins brazed to the flat hollow bodies, and the heat exchanger component described above is provided. The heat exchanger according to any one of the above 1) to 12), which is a flat hollow body.

  14) A plurality of parallel flat hollow bodies having a fluid passage therein, and fins arranged between adjacent flat hollow bodies and fins brazed to the flat hollow bodies, wherein the flat hollow bodies have peripheral portions. Swelled fluid passages and swelled header forming portions connected to both ends of the fluid passages are provided between the two plates, and the heat exchanger constituting member is a plate. The heat exchanger according to any one of 1) to 12).

  15) The heat exchanger according to the above 13) or 14), wherein a fluid containing an acidic component flows through at least one of a fluid passage in the flat hollow body and a gap between adjacent flat hollow bodies.

  16) The fuel hydrogen gas generated by the reforming in the fuel cell system flows through the gap between the adjacent flat hollow bodies, and the outer peripheral surface of the flat hollow body is covered with an Al-Si alloy layer. A fluoride layer is formed on a surface portion of the Al-Si alloy layer, the Al-Si alloy layer has a portion having a Si content of 1.65% by mass or less, and has an outer peripheral surface of a flat hollow body and a fin. The heat exchanger according to any one of the above 13) to 15), wherein a catalyst for selectively oxidizing CO is attached to a surface of the fuel cell, and the catalyst reduces CO in the fuel hydrogen gas.

  17) A fuel cell system including the heat exchanger according to any one of the above 1) to 16) for reducing CO.

  18) A fuel cell vehicle equipped with the fuel cell system according to 17).

  19) A cogeneration system including the fuel cell system according to 17).

  20) a bulging portion for forming a fluid passage using a brazing sheet in which both surfaces of a core material made of pure aluminum or an aluminum alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy brazing; A plate having a header-forming bulging portion bulging out from the fluid-channel-forming bulging portion and connected to both ends of the fluid-channel-forming bulging portion is provided. Are stacked such that the bottom wall outer surfaces of the header-forming bulging portions are in contact with each other, and a portion of the adjacent plate pair corresponding to the fluid-passage-forming bulging portion in the adjacent plate pair. Fins made of pure aluminum or an aluminum alloy bare material are placed on the brazing plate, and the plate body is formed by preheating the combination of the plate pair and the fins. After the preheating, the peripheral portions of the two plates constituting the plate pair are brazed together to form a flat hollow body, and fins are formed on the flat hollow body. After the brazing, the brazing body of the flat hollow body and the fins is heated in an atmosphere containing a fluoridation gas after brazing, thereby forming a fluoride layer on the surface of the flat hollow body and the surface of the fin. A method for manufacturing a heat exchanger.

  21) Both sides of a core material made of pure aluminum or an aluminum alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy brazing, and between at least one of the skin material and the core material. A fluid passage forming bulge, and a header bulging from the fluid passage forming bulge and connected to both ends of the fluid passage forming bulge using a brazing sheet having an intermediate layer made of pure aluminum formed thereon. To form a plate having a bulging portion for formation, a plate pair formed by combining two plates so that the openings of both bulging portions face each other is formed on the outer surface of the bottom wall of the bulging portion for header formation. A plurality of fins made of pure aluminum or an aluminum alloy bare material should be placed between the portions corresponding to the bulging portions for forming the fluid passages in the adjacent plate pair, while laminating the fins so as to abut each other. Forming the flat hollow body by brazing the peripheral edges of both plates constituting the plate pair, brazing the fin to the flat hollow body, and brazing the flat hollow body and the fin after brazing. Is heated in a fluoridation treatment atmosphere containing a fluoridation treatment gas, thereby forming a fluoride layer on the surface of the flat hollow body on the side where the intermediate layer is present and on the surface of the fin. Exchanger manufacturing method.

  22) The method for producing a heat exchanger as described in 21) above, wherein a total of 0.1 to 0.25% by mass of Zr and / or Mg is added to pure aluminum constituting the intermediate layer of the brazing sheet forming the plate. .

  23) The method for manufacturing a heat exchanger according to the above 21) or 22), wherein the ratio of the thickness of the intermediate layer of the brazing sheet forming the plate is 5 to 25% with respect to the total thickness of the brazing sheet of 100%.

  24) The method for manufacturing a heat exchanger according to any one of the above 20) to 23), wherein the core material and the fins of the brazing sheet forming the plate are each made of a JIS A3003 alloy.

  25) The heat exchange according to any one of the above 20) to 24), wherein the ratio of the thickness of the skin material of the brazing sheet forming the plate is 2 to 25% with respect to 100% of the total thickness of the brazing sheet. Method of manufacturing the vessel.

  26) The fluoridation gas is at least one gas selected from the group consisting of fluorine gas, chlorine trifluoride gas, and nitrogen fluoride gas, and is obtained by diluting the fluoridation gas into an inert gas. 26. The method for producing a heat exchanger according to any one of the above 20) to 25), wherein the fluoridation treatment atmosphere is formed.

  27) The method for producing a heat exchanger according to the above 26), wherein the concentration of the fluoridation gas in the fluoridation treatment atmosphere is 5 to 80%.

  28) The method for producing a heat exchanger according to the above 26), wherein the concentration of the fluoridation gas in the fluoridation atmosphere is 10 to 60%.

  29) Production of the heat exchanger according to any one of the above 20) to 28), wherein after forming the fluoride layer, a catalyst for selectively oxidizing CO is attached to the outer peripheral surface of the flat hollow body and the surface of the fin. Method.

  30) A component whose surface is covered with the Al-Si alloy layer and in which a fluoride layer is formed on the surface of the Al-Si alloy layer is provided. Pure aluminum or aluminum alloy products having a portion whose amount is 1.65% by mass or less.

  31) The pure aluminum or aluminum alloy product as described in 30) above, wherein the thickness of the fluoride layer is 2 nm to 10 μm.

  32) The pure aluminum or aluminum alloy product according to the above item 30) or 31), wherein the fluoride layer is made of a fluoride produced by subjecting a surface of the Al—Si alloy layer of the constituent member to fluorination treatment.

  33) An anodic oxide film is formed on the surface of the Al-Si alloy layer of the constituent member, a plating layer containing nickel is formed on the surface of the anodic oxide film, and a fluoride layer is formed on the surface of the plating layer. The pure aluminum or aluminum alloy product according to the above item 30) or 31), wherein the fluoride layer is made of a fluoride produced by fluorinating the surface of the plating layer.

  34) On the surface of the fluoride layer, at least one laminated group composed of a plating layer containing nickel and a fluoride layer made of fluoride generated by fluorinating the surface of the plating layer is formed. Pure aluminum or aluminum alloy products according to any one of the above 30) to 33).

  35) The constituent members include a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer. Si from the Al-Si alloy layer is diffused into the core layer, and each Al-Si alloy layer is diffused. The pure aluminum or aluminum alloy product according to any one of the above 30) to 34), wherein the Si alloy layer has a portion having a Si content of 1.65% by mass or less.

  36) The pure aluminum or aluminum alloy product according to the above 35), wherein at least one surface of the component is exposed to a fluid containing an acidic component or an alkaline component.

  37) The constituent member has a portion composed of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and any one of the Al-Si alloy layer and the core layer An intermediate layer made of pure aluminum is formed between the layers. Si from the Al-Si alloy layer is diffused into the intermediate layer, and the Al-Si alloy layer on the side where the intermediate layer is formed has a Si content. 35) The pure aluminum or aluminum alloy product according to any one of the above items 30) to 34), wherein the product has a portion of 1.65% by mass or less.

  38) The component member comprises a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and a space between both the Al-Si alloy layer and the core layer made of pure aluminum. An intermediate layer is formed, Si from the Al-Si alloy layer is diffused into each intermediate layer, and each Al-Si alloy layer has a portion having a Si content of 1.65% by mass or less. Pure aluminum or aluminum alloy products according to any one of the above 30) to 34).

  39) The pure aluminum or aluminum alloy product as described in 37) or 38) above, wherein Zr and / or Mg are added to the pure aluminum constituting the intermediate layer in a total amount of 0.1 to 0.25% by mass.

  40) The pure aluminum or aluminum alloy product according to any one of 37) to 39), wherein the ratio of the thickness of the intermediate layer is 5 to 25% with respect to 100% of the total thickness of the constituent members.

  41) The pure aluminum or aluminum alloy product according to any one of 37) to 40), wherein the surface of the component on the side where the intermediate layer is present is exposed to a fluid containing an acidic component or an alkaline component.

  Note that the present invention also includes the following aspects.

  a) Both surfaces of a core material made of pure aluminum or an aluminum alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy braze, and between at least one of the skin material and the core material. A brazing sheet for manufacturing a heat exchanger, comprising an intermediate layer made of pure aluminum formed thereon.

  b) The brazing sheet for producing a heat exchanger as described in a) above, wherein Zr and / or Mg are added to pure aluminum constituting the intermediate layer in a total amount of 0.1 to 0.25% by mass.

  c) The brazing sheet for producing a heat exchanger according to the above a) or b), wherein the ratio of the thickness of the intermediate layer is 5 to 25% with respect to 100% of the total thickness.

  d) The brazing sheet for manufacturing a heat exchanger according to any one of the above a) to c), wherein the core material is made of a JIS A3003 alloy.

  e) The brazing sheet for heat exchanger production according to any one of the above a) to d), wherein the ratio of the thickness of the skin material is 2 to 25% with respect to 100% of the total thickness.

According to the heat exchanger of 1), since the Al-Si alloy layer of the heat exchanger constituent member has a portion where the Si content is 1.65% by mass or less, the Al-Si alloy layer Al-Si 12% by mass eutectic hardly exists, and the generation of SiF ₄ during the fluorination treatment for forming the fluoride layer is suppressed, so that a fluoride layer having a required thickness is uniformly formed. It becomes possible to do. Therefore, the corrosion resistance of the heat exchanger component is improved. Further, since Al-Si 12% by mass eutectic hardly exists in the Al-Si alloy layer, even if a defect exists in the fluoride layer, even if it touches a fluid having an acidic component, Al-Si Corrosion of the core layer on the inner side of the Al—Si alloy layer from the crystal grain boundary of Si 12 mass% eutectic is prevented.

  According to the heat exchanger of the above 2), sufficient corrosion resistance to acids can be obtained while reducing the production cost.

  According to the heat exchangers of the above 4) and 5), the components of the heat exchanger have more excellent corrosion resistance against acid.

  According to the heat exchanger of 6), most of the Si content of the Al—Si alloy layer becomes 1.65 mass% or less because Si of the Al—Si alloy layer is diffused into the core layer. This has the same effect as the heat exchanger of the above 1).

  According to the heat exchanger of the above item 7), corrosion is suppressed even if the heat exchanger component is made into a fluid having an acidic component.

  According to the heat exchangers of 8) and 9), Si in the Al—Si alloy layer is diffused into the intermediate layer, so that the Si content of most of the Al—Si alloy layer is 1.65 mass%. % Or less, and has the same effect as the heat exchanger of 1).

  According to the heat exchanger of the above 10), the crystal grains of pure aluminum constituting the intermediate layer are large, and even in the diffusion layer where Si is diffused from the Al-Si alloy layer, Al-12 mass% Si eutectic is formed. No longer formed, resulting in improved corrosion resistance.

  In the heat exchanger of the above 13) to 15), when a fluid having an acidic component flows in at least one of the fluid passage in the flat hollow body and between the adjacent flat hollow bodies, the fluid in the flat hollow body The exposed surface is mostly covered with an Al-Si alloy layer having a Si content of 1.65% by mass or less, and a fluoride layer is formed on the surface of the Al-Si alloy layer. Further, corrosion of the flat hollow body by the fluid having an acidic component is prevented.

  In the heat exchanger of the above 16), since the acidic hydrogen component is contained in the fuel hydrogen gas generated by the reforming, the surface of the flat hollow body exposed to the fuel hydrogen gas has most of the Si content of 1. It is covered with an Al—Si alloy layer of 65% by mass or less, and a fluoride layer is formed on the surface of the Al—Si alloy layer. Further, corrosion of the flat hollow body by the fluid having an acidic component is prevented.

According to the heat exchanger manufacturing method of the above (20), Si in the skin material of the brazing sheet forming the plate is diffused into the core material by preheating before brazing, so that 12 mass% of Al-Si is contained in the skin material. % Eutectic is not present, the generation of SiF ₄ is suppressed during the fluoridation treatment for forming the fluoride layer after brazing, and the fluoride layer having the required thickness is uniformly formed. Becomes possible. Further, since 12% by mass of Al-Si eutectic does not exist in the skin material, even if a defect exists in the fluoride layer, even if it touches a fluid having an acidic component, it does not exist. The progress of corrosion from the crystal grain boundaries to the core material is prevented.

According to the method for manufacturing a heat exchanger of the above 21), Si in the cladding diffuses into the intermediate layer during brazing, so that the Al-Si 12% by mass eutectic exists in the cladding. In addition, generation of SiF ₄ during the fluorination treatment for forming a fluoride layer after brazing is suppressed, and a fluoride layer having a required thickness can be formed uniformly. Further, since 12% by mass of Al-Si eutectic does not exist in the skin material, even if a defect exists in the fluoride layer, even if it touches a fluid having an acidic component, it does not exist. The progress of corrosion from the crystal grain boundaries to the intermediate layer and the core material is prevented.

  According to the method for manufacturing a heat exchanger of the above 22), the crystal grains of pure aluminum constituting the intermediate layer are large, and even in a diffusion layer formed by diffusing Si from the skin material into the intermediate layer, Al-12 mass is obtained. % Si eutectic no longer forms, resulting in improved corrosion resistance.

  According to the heat exchanger manufacturing methods 27) and 28), a fluoride layer having a required thickness can be formed relatively quickly while reducing manufacturing costs.

  According to the pure aluminum or aluminum alloy product of the above 30), the same effects as those of the heat exchanger of the above 1) can be obtained.

  According to the pure aluminum or aluminum alloy product of the above 31), the same effect as that of the heat exchanger of the above 2) can be obtained.

  According to the pure aluminum or aluminum alloy products of 33) to 39), the same effects as those of the heat exchangers of 4) to 10) can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the following description, the vertical and horizontal directions in FIG. 1 are referred to as vertical and horizontal directions, respectively.

  FIG. 1 shows the overall configuration of a heat exchanger according to the present invention, and FIGS. 2 and 3 show the configuration of the main part thereof.

  1 and 2, the heat exchanger (1) is composed of two plate-like plates (2) whose peripheral edges are brazed, and a swelling fluid passage (3) between both plates (2). And a plurality of parallel flat hollow bodies (5) provided with bulging header forming portions (4) connected to both left and right ends thereof.

  The fluid passage (3) and the bulging header forming portion (4) of the flat hollow body (5) are formed with a bulging portion (2a) for forming a fluid passage and a bulging portion for forming a fluid passage formed on both plates (2). The opening of the header forming bulging portion (2b) connected to the left and right ends of the protruding portion (2a) is formed to face each other. The height of the header forming part (4) of each flat hollow body (5) is larger than the height of the fluid passage (3), and the header forming parts (4) of the adjacent flat hollow bodies (5) are communicated with each other. Thus, the left and right headers (6) are formed. Inside the fluid passage (3), an inner corrugated fin (7) made of a bare material of pure aluminum or an aluminum alloy is arranged and brazed to both plates (2). The gap between the portions corresponding to the fluid passages (3) of the adjacent flat hollow bodies (5) is a gas-phase fluid passage (8), where the outer corrugated fins (pure aluminum or aluminum alloy bare material) are formed. 9) is arranged and brazed to the flat hollow body (5). Outside the portions corresponding to the fluid passages (3) in the flat hollow bodies (5) at the upper and lower ends, side plates (10) made of bare material of pure aluminum or an aluminum alloy are arranged at intervals, respectively, at the upper and lower ends. A gas-phase fluid passage (8) is also formed between the flat hollow body (5) and both side plates (10), and an outer corrugated fin (9) is also arranged in this gas-phase fluid passage (8). It is brazed to the flat hollow body (5) and the side plate (10). Both ends of the side plate (10) are bent inward in the up-down direction and brazed to the header forming portions (4) of the flat hollow bodies (5) at both the upper and lower ends. The fluid inlet pipe (11) is joined to the upper end of the left header (6), and the fluid outlet pipe (12) is joined to the lower end of the right header (6). The fluid that has flowed into the left header (6) from the fluid inlet pipe (11) branches into the fluid passages (3) of all the flat hollow bodies (5) and flows into the right header (6). Out of the fluid outlet tube (12).

  In this embodiment, the plate (2) forming the flat hollow body (5) is a heat exchanger component according to the present invention. As shown in FIG. 3, the plate (2) includes a core layer (21) made of pure aluminum or an aluminum alloy, here, a JIS A3003 alloy, and an Al-Si alloy layer (22) covering both surfaces of the core layer (21). And a fluoride layer (23) formed on the surface of the Al-Si alloy layer (22). The core layer (21) is not limited to JIS A3003 alloy.

Si from the Al—Si alloy layer (22) is diffused into the core layer (21). This diffusion layer is indicated by (24). The Si content of most of the entire Al-Si alloy layers (22) is 1.65% by mass or less. That is, in the part where the fillet formed at the place where the two corrugated fins (7) and (9) in the plate (2) are brazed, and the part where the plate (2) is bent, etc., the Al-Si alloy layer Although the Si content in (22) may exceed 1.65% by mass, the Si content in the other portion of the Al-Si alloy layer (22) is 1.65% by mass or less. When the Si content of most of the entire Al-Si alloy layers (22) is 1.65% by mass or less, 12% by mass of Al-Si eutectic exists in the Al-Si alloy layers (22). Therefore, the generation of SiF ₄ during the fluorination treatment for forming the fluoride layer (23) is suppressed, and the fluoride layer (23) having a required thickness can be formed uniformly. Become. Also, since there is no Al-Si 12% by mass eutectic in the Al-Si alloy layer (22), if a defect exists in the fluoride layer (23), the fluid passage (3) or the vapor phase Even if a fluid having an acidic component flows through the fluid passage (8), the progress of corrosion from the grain boundaries of Al-Si 12% by mass eutectic to the core layer (21) is prevented.

  The fluoride layer (23) is made of fluoride generated by subjecting the surface of the Al-Si alloy layer (22) of the plate (2) to fluorination treatment. The thickness of the fluoride layer (23) is preferably 2 nm to 10 μm. If the thickness of the fluoride layer (23) is less than 2 nm, the corrosion resistance to acids is not sufficient, and corrosion may occur in a relatively short time. If the thickness exceeds 10 μm, sufficient corrosion resistance is obtained, but It takes a lot of time to form the layer (23), which increases the production cost of the heat exchanger (1). It is desirable that the thickness of the fluoride layer (23) is 20 nm to 3 μm.

The heat exchanger (1) is used as a CO-reducing heat exchanger for reducing CO in fuel hydrogen gas generated by a reformer in a fuel cell system used for a fuel cell vehicle or a cogeneration system, for example. In this case, a catalyst (not shown) for selectively oxidizing CO is attached to the outer peripheral surface of the flat hollow body (5), that is, the outer surface of the plate (2) and the surface of the outer corrugated fin (9). The catalyst may be attached to the outer surface of the plate (2) and the surface of the outer corrugated fin (9) while being supported on a carrier. As this catalyst, for example, a Cu—Zn catalyst or a zeolite catalyst is used, but the catalyst is not limited thereto. The catalyst promotes a reaction of CO + 1 / 2O ₂ → CO _{2 and} reduces CO in fuel hydrogen gas.

  When the heat exchanger (1) is used for reducing CO in fuel hydrogen gas, the fuel hydrogen gas flows through the gas phase fluid passage (8) (see arrow A in FIG. 1), and the refrigerant flowing through the fluid passage (3) For example, the catalyst reduces CO while being cooled by long-life coolant-containing water or water.

  When used as a heat exchanger for reducing CO, the Si content of the inner peripheral surface of the flat hollow body (5), that is, the Al—Si alloy layer (22) on the inner surface side of the plate (2) is not necessarily 1.65. It does not need to be less than 10% by mass, and the fluoride layer (23) need not be formed on the surface layer. This is because there is no problem with the water containing long life coolant and the corrosion resistance to water.

  Further, when a fluid containing an acidic component flows through both the fluid passage (3) and the gas-phase fluid passage (8), the inner and outer peripheral surfaces of the flat hollow body (5), that is, the Al -The Si content of most of the entire Si alloy layer (22) is set to 1.65 mass% or less, and the fluoride layer (23) is formed on the surface of the Al-Si alloy layer (22).

  The heat exchanger (1) is manufactured as follows.

  First, both surfaces of a core material made of pure aluminum or an aluminum alloy, here a JIS A3003 alloy, are covered with a skin material made of an Al-7.5 to 12.5 mass% Si alloy solder, here a JIS A4004 alloy solder. A brazing sheet of a layer clad is prepared, and the brazing sheet is subjected to press working, so that the bulging portion (2a) for forming the fluid passage and the bulging portion (2a) for forming the fluid passage are formed and the fluid passage is formed. A plate (2) having a header forming bulge (2b) connected to both ends of the bulge (2a) is made. The ratio of the thickness of the skin material of the brazing sheet is preferably set to 2 to 25% with respect to the total thickness of the brazing sheet of 100%. This is because it is difficult to produce the brazing sheet by rolling outside this range.

  Next, a plate pair formed by combining the two plates (2) so that the openings of both the bulging portions (2a) and (2b) face each other is connected to the bottom wall outer surface of the header forming bulging portion (2b). Outer corrugated fins made of pure aluminum or an aluminum alloy, here a JIS A3003 alloy, between the portions corresponding to the fluid passage forming bulges (2a) in adjacent plate pairs Place (9). In addition, a bare material of pure aluminum or an aluminum alloy, here an inner corrugated fin (7) made of JIS A3003 alloy, is arranged in the bulging portion (2a) for forming a fluid passage of both plates (2) constituting a plate pair. .

  Then, the combined body consisting of the plate pair and both corrugated fins (7) and (9) is preheated to diffuse Si in the skin of the brazing sheet forming the plate (2) into the core, and to contain Si in the skin. The amount is not more than 1.65% by mass. This preheating is performed by changing the preheating time and / or temperature during normal brazing. For example, when changing the preheating time, the preheating time is set to be 1.5 to 2 times longer than the normal preheating time during brazing. When changing the preheating temperature, the preheating temperature is set higher than the preheating temperature during normal brazing.

  Then, after preheating, the peripheral edges of both plates (2) constituting the plate pair are brazed together to form a flat hollow body (5), and both corrugated fins (7) (9) are attached to the flat hollow body (5). ).

Thereafter, the brazed body of the flat hollow body (5) and the corrugated fins (7) and (9) is heated in an atmosphere containing a fluoridation gas, so that the inside and outside of the flat hollow body (5) are heated. A fluoride layer (23) is formed on the peripheral surface, that is, on the inner and outer surfaces of the plate (2) and on the surfaces of both corrugated fins (7) and (9). The fluoridation gas is at least one gas selected from the group consisting of a fluorine gas, a chlorine trifluoride gas and a nitrogen fluoride gas. Form a processing atmosphere. The concentration of the fluoridation gas in the fluoridation atmosphere is preferably 5 to 80%. If the concentration of the fluoridation gas in the fluoridation treatment atmosphere is less than 5%, the fluoride layer (23) having a required thickness cannot be formed, and it becomes difficult to obtain a desired corrosion resistance. As the concentration increases, the formation rate of the fluoride layer (23) can be increased. However, when the concentration exceeds 80%, the effect of increasing the formation rate of the fluoride layer (23) is saturated, and the concentration is reduced. There is a problem in that there is no point in increasing the manufacturing cost and the manufacturing cost increases. Therefore, the concentration of the fluoridation gas is preferably 5 to 80%, and more preferably 10 to 60%. As the inert gas, various inert gases such as N ₂ gas, Ar gas, and He gas are used, and it is particularly preferable to use N ₂ gas. Further, the fluoridation treatment is preferably performed by holding at 100 ° C. or more for 5 hours or more in a fluoridation treatment atmosphere. If the holding temperature is less than 100 ° C. or the holding time is less than 5 hours, diffusion to the inner and outer surfaces of the plate (2) and the surface layer of the corrugated fins (7) and (9) hardly occurs. This is because the oxide layer (23) is not formed. It is desirable that the holding temperature is 150 ° C. or more and the holding time is 10 hours or more. The upper limit of the holding temperature is 600 ° C. or less, and the upper limit of the holding time is 50 hours or less. Further, the pressure of the fluoridation treatment atmosphere is not particularly limited and can be variously set, but is preferably in the range of 0.8 × 10 ^{5 to} 1.5 × 10 ⁵ Pa.

  Thus, the heat exchanger (1) is manufactured.

  As described above, this heat exchanger (1) is used for reducing CO in fuel hydrogen gas generated by the reformer in a fuel cell system used in a fuel cell vehicle or a cogeneration system. When used as a heat exchanger, after the fluorination treatment, CO is selectively oxidized on the outer peripheral surface of the flat hollow body (5), that is, the outer surface of the plate (2) and the surface of the outer corrugated fin (9). The catalyst to be deposited.

  FIG. 4 shows a modified example of a plate as a heat exchanger component constituting the flat hollow body (5) of the heat exchanger (1).

  As shown in FIG. 4, the plate (30) is composed of a core layer (31) made of pure aluminum or an aluminum alloy, here, a JIS A3003 alloy, and an Al—Si alloy layer (32) covering both surfaces of the core layer (31). And pure aluminum formed between the two Al-Si alloy layers (32) and the core layer (31), respectively, an intermediate layer (33) made of JIS A1050, and an Al-Si alloy layer (32). And a fluoride layer (34) formed on the surface layer. The core layer (31) is not limited to JIS A3003 alloy, and the intermediate layer (33) is not limited to JIS A1050.

  The Si content of most of the entire Al-Si alloy layers (32) is 1.65% by mass or less, as described for the plate (2) shown in FIG.

  Si from the Al-Si alloy layer (32) is diffused in the intermediate layer (33). The diffusion layer is indicated by (35). It is preferable that Zr and / or Mg be added to JIS A1050 constituting the intermediate layer (33) in a total amount of 0.1 to 0.25% by mass. When Zr and / or Mg are added, the crystal grains of JIS A1050 constituting the intermediate layer (33) become large, and the diffusion layer (35) in which Si from the Al-Si alloy layer (32) is diffused. In this case, no Al-12 mass% Si eutectic is generated. However, if the total amount is less than 0.1% by mass, such an effect cannot be obtained. If the total amount exceeds 0.25% by mass, the cost is increased. It is preferably 25% by mass. The ratio of the thickness of the intermediate layer (33) is preferably 5 to 25% with respect to the total thickness of the plate (30) in consideration of corrosion resistance and cost, and is preferably 15 to 25%. Is desirable.

  The fluoride layer (34) is made of fluoride generated by subjecting the surface of the Al-Si alloy layer (32) of the plate (30) to fluorination treatment, and is similar to the case of the plate (2) shown in FIG. For that reason, the thickness is preferably from 2 nm to 10 μm, more preferably from 20 nm to 3 μm.

  A heat exchanger (1) having a flat hollow body (5) formed by such a plate (30) is generated by a reformer in a fuel cell system used for a fuel cell vehicle or a cogeneration system, for example. When used as a CO reduction heat exchanger for reducing CO in fuel hydrogen gas, the inner peripheral surface side of the flat hollow body (5), that is, the Al-Si alloy layer (32) on the inner surface side of the plate (30) is used. The Si content does not necessarily need to be 1.65% by mass or less, and the fluoride layer (34) need not be formed on the surface thereof. Further, the intermediate layer (33) does not need to be formed on the inner surface side of the plate (30). This is because there is no problem with the water containing long life coolant and the corrosion resistance to water.

  When a fluid containing an acidic component flows through both the fluid passage (3) and the gas-phase fluid passage (8), the inner and outer peripheral surfaces of the flat hollow body (5), that is, the inner and outer surfaces of the plate (30), -The Si content of most of the entire Si alloy layer (32) is set to 1.65% by mass or less, and the intermediate layer (33) is provided between both the Al-Si alloy layer (32) and the core layer (31). ), And a fluoride layer (34) must be formed on the surface of the Al—Si alloy layer (32).

  The heat exchanger (1) having the plate (30) shown in FIG. 4 is manufactured as follows.

  First, both surfaces of a core material made of pure aluminum or an aluminum alloy, here, a JIS A3003 alloy, are covered with a skin material made of an Al-7.5 to 12.5 mass% Si alloy solder, here, a JIS A4004 alloy solder, and Prepare a 5-layer clad brazing sheet with an intermediate layer made of pure aluminum, here JIS A1050, formed between the skin material and the core material, and press-work the brazing sheet to form a fluid passage. Bulging portion (2a), and a bulging portion for header formation (2b) bulging out from the bulging portion for fluid passage formation (2a) and connected to both ends of the bulging portion for fluid passage formation (2a). Make a plate (30). It is preferable that the intermediate layer (33) of the brazing sheet contains a total of 0.1 to 0.25% by mass of Zr and / or Mg. The ratio of the thickness of the skin material of the brazing sheet is 2 to 25% with respect to the total thickness of the brazing sheet of 100%, and the ratio of the thickness of the intermediate layer (33) of the brazing sheet is 100% of the total thickness of the brazing sheet. 5 to 25%, preferably 15 to 25%.

  Next, a plate pair formed by combining the two plates (30) such that the openings of both the bulging portions (2a) and (2b) face each other is connected to the bottom wall outer surface of the header forming bulging portion (2b). Outer corrugated fins made of pure aluminum or an aluminum alloy, here a JIS A3003 alloy, between the portions corresponding to the fluid passage forming bulges (2a) in adjacent plate pairs Place (9). In addition, a bare material of pure aluminum or an aluminum alloy, here an inner corrugated fin (7) made of JIS A3003 alloy, is arranged in the bulging portion (2a) for forming a fluid passage of both plates (2) constituting a plate pair. .

  Next, the peripheral edges of both plates (30) constituting the plate pair are brazed together to form a flat hollow body (5), and both flat corrugated fins (7) and (9) are brazed to the flat hollow body (5). Attached. At the time of this brazing, normal preheating of brazing is performed unlike the case of the first method described above.

  Then, by the same fluoridation treatment method as the first method described above, the inner and outer peripheral surfaces of the flat hollow body (5), that is, both the inner and outer surfaces of the plate (30) and the surfaces of both corrugated fins (7) and (9) A fluoride layer (34) is formed.

  Thus, the heat exchanger (1) is manufactured.

  As described above, this heat exchanger (1) is used for reducing CO in fuel hydrogen gas generated by the reformer in a fuel cell system used in a fuel cell vehicle or a cogeneration system. When used as a heat exchanger, after the fluorination treatment, a catalyst that selectively oxidizes CO on the outer peripheral surface of the flat hollow body (5), that is, the outer surface of the plate (30), and the surface of the outer corrugated fin (9). Attach.

  Further, as described above, in the fuel cell system used for the fuel cell vehicle or the cogeneration system, the heat exchanger (1) serves as a CO reducing heat for reducing the CO in the fuel hydrogen gas generated by the reformer. When used as an exchanger, pure aluminum or aluminum alloy, here JIS A3003, is used because a fluid containing no acidic component such as water containing long life coolant flows in the fluid passage (3) of the flat hollow body (5). Both surfaces of a core material made of an alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy brazing, here a JIS A4004 alloy brazing material, and between one of the skin materials and the core material. A four-layer clad brazing sheet having an intermediate layer formed of pure aluminum, here JIS A1050, may be used. The fluid passage forming bulge (2a) and the header forming bulge (2b) which are higher than the fluid passage bulging portion (2a) and are connected to both ends of the fluid passage forming bulge (2a). )), The four-layer clad brazing sheet is pressed so that the side on which the intermediate layer is present is on the outside.

  FIG. 5 shows another modified example of a plate as a heat exchanger component constituting the flat hollow body (5) of the heat exchanger (1).

  As shown in FIG. 5, the plate (60) includes a core layer (31) made of pure aluminum or an aluminum alloy, here, a JIS A3003 alloy, and an Al—Si alloy layer (32) covering both surfaces of the core layer (31). And pure aluminum formed between the two Al-Si alloy layers (32) and the core layer (31), respectively, an intermediate layer (33) made of JIS A1050, and an Al-Si alloy layer (32). Anodized film (61) formed on the surface, a plated layer (62) formed on the surface of the anodized film (61) and containing nickel, and a fluoride layer formed on the surface of the plated layer (62) The diffusion layer (35) is formed by diffusion of Si from the Al—Si alloy layer (32) into the intermediate layer (33).

  The core layer (31), the two Al-Si alloy layers (32), the intermediate layer (33), and the diffusion layer (35) have the same configuration as the plate (30) shown in FIG.

  The plating layer (62) is made of, for example, electroless nickel plating or electroless nickel-phosphorus alloy plating. The fluoride layer (63) is made of fluoride generated by subjecting the surface of the plating layer (62) to fluorination treatment.

  FIG. 6 shows still another modified example of a plate as a heat exchanger component constituting the flat hollow body (5) of the heat exchanger (1).

  As shown in FIG. 6, the plate (70) has a plating layer (71) containing nickel and a surface of the plating layer (71) on the surface of the fluoride layer (34) of the plate (30) shown in FIG. One laminated group (73) consisting of the formed fluoride layer (72) is formed.

  The plating layer (71) is made of, for example, electroless nickel plating or electroless nickel-phosphorus alloy plating. The fluoride layer (72) is made of fluoride generated by subjecting the surface of the plating layer (71) to fluorination treatment. Although one lamination group (73) is formed here, the number is not limited to this, and two or more lamination groups may be formed. For example, when two laminated groups (73) are formed, a plating layer containing nickel is further formed on the surface of the fluoride layer (72) of the laminated group (73), and the plating layer is formed on the surface of the plating layer. A fluoride layer made of fluoride generated by fluorinating the surface is formed. Even when three or more stacked groups (73) are formed, the stacked groups (73) are formed such that the fluoride layer (72) comes to the outermost surface.

  A heat exchanger (1) having a flat hollow body (5) formed by plates (60) and (70) shown in FIGS. 5 and 6 is used in a fuel cell system used for a fuel cell vehicle or a cogeneration system, for example. When used as a CO reduction heat exchanger that reduces CO in fuel hydrogen gas generated by the reformer, the inner peripheral side of the flat hollow body (5), that is, the inner side of the plates (60) and (70) The Al content of the Al—Si alloy layer (32) does not necessarily need to be 1.65 mass% or less, and the surface of the Al—Si alloy layer (32) has an anodic oxide film (61) and a plating layer ( 62) and the fluoride layer (63), or the fluoride layer (34) and the laminated group (73) need not be formed. Further, the intermediate layer (33) does not need to be formed on the inner surface side of the plates (60) and (70). This is because there is no problem with the water containing long life coolant and the corrosion resistance to water.

  When a fluid containing an acidic component flows through both the fluid passage (3) and the gas-phase fluid passage (8), the inner and outer peripheral surfaces of the flat hollow body (5), that is, the inner and outer surfaces of the plates (60) and (70), The Si content of the majority of the entire Al-Si alloy layer (32) on both surfaces is set to 1.65% by mass or less, and an intermediate portion is provided between the Al-Si alloy layer (32) and the core layer (31). A layer (33) is formed, and further, on the surface of the Al-Si alloy layer (32), an anodic oxide film (61), a plating layer (62) and a fluoride layer (63), and a fluoride layer (34) and It is necessary to form a stacking group (73).

  Next, an experimental example performed to verify the effect of the present invention will be shown together with a comparative experimental example.

  An intermediate layer made of pure aluminum with both sides of a core material made of JIS A3003 alloy covered with a skin material made of JIS A4004 alloy braze, and between one skin material and the core material, Zr 0.15% by mass is added. A specimen X having a length of 100 mm, a width of 50 mm and a thickness of 0.4 mm was prepared from the brazing sheet on which was formed. The ratio of the thickness of the core material, each skin material, and the intermediate layer to the total thickness of 100% in the specimen X is 54%, 13%, and 20%, respectively. A sample Y having a length of 100 mm, a width of 50 mm, and a thickness of 0.5 mm was prepared from a brazing sheet in which both surfaces of a core material made of JIS A3003 alloy were covered with a skin material made of JIS A4004 alloy braze. The ratio of the thickness of the core material and the thickness of each skin material to the total thickness of 100% in the sample Y is 70% and 15%, respectively.

Experimental example 1
Specimen X was placed in a vacuum heating furnace, heated at 575 ° C. for 40 minutes, and then heated at 612 ° C. for 12 minutes. Then, the specimen X was taken out of the vacuum heating furnace, placed in an atmosphere heating furnace, and a mixed gas of fluorine gas and an inert gas was introduced into the atmosphere heating furnace to set the atmosphere heating furnace to a fluoridation treatment atmosphere. Specimen X was heated at 400 ° C. for 24 hours to perform a fluorination treatment. The fluorine gas concentration in this fluoridation atmosphere was set to 20%.

The specimen X was taken out of the atmosphere heating furnace, and its cross section was observed. The result was as shown in FIG. In FIG. 7, (40) is a core material, (41) is a skin material on which the intermediate layer is formed, (42) is a skin material on which the intermediate layer is not formed, and (43) is an intermediate layer. As is clear from FIG. 7, the surface of the skin material (41) on the side where the intermediate layer (43) was formed hardly changed, and there was no Al-12 mass% Si eutectic. The surface of the skin material (42) on which the intermediate layer (43) is not formed has remarkable irregularities, and Al-12 mass% Si eutectic exists. From this result, it can be seen that Si contained in the skin material (41) on the side where the intermediate layer (43) was formed is diffused into the intermediate layer (43). On the other hand, in the skin material (42) on the side where the intermediate layer (43) is not formed, Si does not diffuse, and SiF ₄ is generated and evaporated at the Al-12 mass% Si eutectic part during the fluorination treatment. It can be seen that Al-12 mass% Si eutectic remained.

Experimental example 2
Specimen X was treated under the same conditions as in Experimental Example 1 except that the holding temperature during the fluoridation treatment was changed to 500 ° C.

  When the sample X was taken out of the atmosphere heating furnace and its surface was observed, the surface on which the intermediate layer was formed was a smooth white surface, and remarkable unevenness occurred on the opposite side.

Experimental example 3
Specimen Y was placed in a vacuum heating furnace, heated at 575 ° C. for 40 minutes, and then heated at 612 ° C. for 12 minutes. Next, the sample Y was once taken out of the vacuum heating furnace, placed in the vacuum heating furnace again, heated at 575 ° C. for 40 minutes, and then heated at 612 ° C. for 12 minutes. Thereafter, the sample Y was taken out of the vacuum heating furnace, placed in an atmosphere heating furnace, and a mixed gas of a fluorine gas and an inert gas was introduced into the atmosphere heating furnace to make the atmosphere heating furnace a fluoridation treatment atmosphere. . The fluorine gas concentration in this fluoridation atmosphere was set to 20%. Then, the sample Y was heated at 260 ° C. for 24 hours.

  When the sample Y was taken out of the atmosphere heating furnace and its surface was observed, the surface was smooth white.

Experimental example 4
Specimen Y was treated under the same conditions as in Experimental Example 3 except that the holding temperature during the fluoridation treatment was changed to 400 ° C.

  When the sample Y was taken out of the atmosphere heating furnace and its surface was observed, the surface was smooth brown.

Experimental example 5
Specimen Y was treated under the same conditions as in Experimental Example 3 except that the holding temperature during the fluoridation treatment was changed to 500 ° C.

  When the sample Y was taken out of the atmosphere heating furnace and its surface was observed, it was found that brown, fine irregularities were generated.

Comparative Example 1
Specimen Y was placed in a vacuum heating furnace, heated at 575 ° C. for 40 minutes, and then heated at 612 ° C. for 12 minutes. Thereafter, the sample Y was taken out of the vacuum heating furnace, placed in an atmosphere heating furnace, and a mixed gas of a fluorine gas and an inert gas was introduced into the atmosphere heating furnace to make the atmosphere heating furnace a fluoridation treatment atmosphere. Specimen Y was heated at 400 ° C. for 24 hours to perform fluorination treatment. The fluorine gas concentration in this fluoridation atmosphere was set to 20%.

When the sample Y was taken out of the atmosphere heating furnace and its surface was observed, remarkable irregularities were found.
Comparative experimental example 2
Specimen Y was treated under the same conditions as in Comparative Experimental Example 1, except that the holding temperature during the fluoridation treatment was changed to 500 ° C.

  When the sample Y was taken out of the atmosphere heating furnace and its surface was observed, remarkable irregularities were found.

Experimental example 6
Sample X was treated under the same conditions as in Experimental Example 1. Then, a corrosive aqueous solution having a pH of 3 containing 10 ppm of hydrochloric acid, 50 ppm of nitric acid, 1000 ppm of formic acid and 300 ppm of acetic acid was prepared. A corrosion test was performed by repeating 2500 cycles of the corrosion test. Then, the sheet thickness reduction was measured for each predetermined pseudo corrosion cycle. FIG. 8 shows the change in the thickness reduction.

Experimental example 7
Sample Y was treated under the same conditions as in Experimental Example 4. Then, the same corrosion test as in Experimental Example 6 was performed, and the thickness reduction was measured for each predetermined pseudo corrosion cycle. FIG. 8 shows the change in the thickness reduction.

Comparative Experimental Example 3
Specimen Y was placed in a vacuum heating furnace, heated at 575 ° C. for 40 minutes, and then heated at 612 ° C. for 12 minutes. Thereafter, the sample Y was taken out of the vacuum heating furnace, placed in an atmosphere heating furnace, and a mixed gas of a fluorine gas and an inert gas was introduced into the atmosphere heating furnace to make the atmosphere heating furnace a fluoridation treatment atmosphere. . The fluorine gas concentration in this fluoridation atmosphere was set to 20%. Then, the sample Y was heated at 260 ° C. for 24 hours.

  Then, the same corrosion test as in Experimental Example 6 was performed, and the thickness reduction was measured for each predetermined pseudo corrosion cycle. FIG. 8 shows the change in the thickness reduction.

Comparative Experimental Example 4
The same corrosion test as in Experimental Example 6 was performed on a test piece made of JIS SUS304 having a length of 100 mm, a width of 50 mm, and a thickness of 0.9 mm. Then, the sheet thickness reduction was measured for each predetermined pseudo corrosion cycle. FIG. 8 shows the change in the thickness reduction.

Comparative Experimental Example 5
A 100 mm long, 50 mm wide, 0.9 mm thick sample made of JIS A3003 alloy is placed in an atmosphere heating furnace, and a mixed gas of fluorine gas and an inert gas is introduced into the atmosphere heating furnace. The inside was made a fluoridation atmosphere. The fluorine gas concentration in this fluoridation atmosphere was set to 20%. Then, the specimen was heated at 400 ° C. for 24 hours. Thereafter, the same corrosion test as in Experimental Example 6 was performed. Then, the sheet thickness reduction was measured for each predetermined pseudo corrosion cycle. FIG. 8 shows the change in the thickness reduction.

  From the results shown in FIG. 8, it can be seen that the thickness reduction due to corrosion in Experimental Examples 6 and 7 is equivalent to that of stainless steel, and the thickness reduction due to corrosion in Comparative Experimental Example 3 is significant. It should be noted that Comparative Experimental Example 5 is considered to be under the same conditions as the outer corrugated fins in the heat exchanger, and in the fuel cell system used in the fuel cell vehicle or the cogeneration system, the fuel hydrogen gas generated by the reformer in the fuel cell system was used. It has been proved that the outer corrugated fins are hardly corroded even when used as a CO-reducing heat exchanger for reducing CO.

Experimental example 8
Sample X was treated under the same conditions as in Experimental Example 2. Then, a corrosion test was performed under the same conditions as in Experimental Example 6, and the cross section of the test piece X after the completion of the corrosion test was observed, as shown in FIG. In FIG. 9, (50) is a core material, (51) is a skin material on the side where an intermediate layer is formed, (52) is a skin material on a side where no intermediate layer is formed, and (53) is a middle layer. As is apparent from FIG. 9, the surface of the skin material (51) on the side where the intermediate layer (53) was formed hardly changed, and there was no Al-12 mass% Si eutectic. The surface of the skin material (52) on the side where the intermediate layer (53) is not formed has remarkable irregularities, and the corrosion generated from the Al-12 mass% Si eutectic in the skin material (52) is not It had progressed to the core material (50).

  The plates (2) and (30) described above, that is, the heat exchanger constituent members of the present invention have excellent corrosion resistance not only to a fluid containing an acidic component but also to a fluid containing an alkaline component.

  Further, as another embodiment of the present invention, a component having the same configuration as the above-described plate (2) or plate (30), for example, a flat plate, a curved plate, or a pure aluminum having a tubular component. Or an aluminum alloy product is mentioned. In such a pure aluminum or aluminum alloy product, at least one surface of the constituent member is exposed to a fluid containing an acidic component or an alkaline component.

It is a perspective view showing an embodiment of a heat exchanger by this invention. FIG. 2 is a partially cutaway perspective view showing an enlarged main part of the heat exchanger shown in FIG. 1. It is an expanded sectional view which shows the plate which forms the flat hollow body of the heat exchanger shown in FIG. It is an expanded sectional view which shows the modification of the plate which forms the flat hollow body of the heat exchanger shown in FIG. It is an expanded sectional view which shows the other modification of the plate which forms the flat hollow body of the heat exchanger shown in FIG. It is an expanded sectional view which shows another modification of the plate which forms the flat hollow body of the heat exchanger shown in FIG. 4 is a photograph showing the results of Experimental Example 1. It is a graph which shows the result of Experimental Examples 6-7 and Comparative Experimental Examples 3-5. 9 is a photograph showing the results of Experimental Example 8.

Explanation of reference numerals

(1): Heat exchanger
(2): Plate (component of heat exchanger)
(2a): bulge for forming a fluid passage
(2b): bulge for header formation
(3): Fluid passage
(4): Header forming section
(5): Flat hollow body
(8): Gas phase fluid passage
(9): Outer corrugated fin
(21): Core layer
(22): Al-Si alloy layer
(23): Fluoride layer
(30): Plate (component of heat exchanger)
(31): Core layer
(32): Al-Si alloy layer
(33): Middle class
(34): Fluoride layer
(60): Plate (component of heat exchanger)
(61): Anodized film
(62): Plating layer
(63): Fluoride layer
(70): Plate (component of heat exchanger)
(71): Plating layer
(72): Fluoride layer
(73): Laminated group

Claims (41)

A heat exchanger component, the surface of which is covered with an Al-Si alloy layer, and a fluoride layer formed on a surface portion of the Al-Si alloy layer, wherein the Al-Si alloy layer of the heat exchanger component is provided. However, the heat exchanger which has the part whose Si content is 1.65 mass% or less. The heat exchanger according to claim 1, wherein the thickness of the fluoride layer is 2 nm to 10 m. The heat exchanger according to claim 1, wherein the fluoride layer is made of a fluoride generated by subjecting a surface of the Al—Si alloy layer of the heat exchanger component to a fluorination treatment. An anodic oxide film is formed on the surface of the Al-Si alloy layer of the heat exchanger component, a plating layer containing nickel is formed on the surface of the anodic oxide film, and a fluoride layer is formed on the surface of the plating layer. 3. The heat exchanger according to claim 1, wherein the fluoride layer is made of a fluoride generated by subjecting a surface of the plating layer to a fluorination treatment. On the surface of the fluoride layer, at least one laminated group composed of a nickel-containing plating layer and a fluoride layer made of fluoride generated by subjecting the surface of the plating layer to fluorination is formed. The heat exchanger according to any one of claims 1 to 4. The heat exchanger constituent member includes a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer. Si from the Al-Si alloy layer is diffused into the core layer, and each Al The heat exchanger according to any one of claims 1 to 5, wherein the -Si alloy layer has a portion having a Si content of 1.65% by mass or less. 7. The heat exchanger according to claim 6, wherein at least one surface of the heat exchanger component is exposed to a fluid containing an acidic component. The heat exchanger component has a portion composed of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and either one of the Al-Si alloy layer and the core layer And an intermediate layer made of pure aluminum is formed between the intermediate layer and the intermediate layer. Si from the Al-Si alloy layer is diffused into the intermediate layer, and the Al-Si alloy layer on the side where the intermediate layer is formed is The heat exchanger according to any one of claims 1 to 5, wherein the heat exchanger has a portion whose amount is 1.65% by mass or less. The heat exchanger component is composed of a pure aluminum or aluminum alloy core layer and an Al-Si alloy layer covering both surfaces of the core layer. Are formed, Si from the Al-Si alloy layer is diffused into each intermediate layer, and each Al-Si alloy layer has a portion where the Si content is 1.65% by mass or less. The heat exchanger according to any one of claims 1 to 5, wherein The heat exchanger according to claim 8 or 9, wherein Zr and / or Mg are added to the pure aluminum constituting the intermediate layer in a total amount of 0.1 to 0.25% by mass. The heat exchanger according to any one of claims 8 to 10, wherein the ratio of the thickness of the intermediate layer is 5 to 25% with respect to 100% of the total thickness of the heat exchanger constituent members. The heat exchanger according to any one of claims 8 to 11, wherein a surface of the heat exchanger component on the side where the intermediate layer exists is exposed to a fluid containing an acidic component. A plurality of parallel flat hollow bodies having a fluid passage therein, and fins disposed between adjacent flat hollow bodies and brazed to the flat hollow bodies are provided, and the above-described heat exchanger component member is a flat hollow body. The heat exchanger according to any one of claims 1 to 12, which is a body. A plurality of parallel flat hollow bodies having a fluid passage therein, and fins disposed between adjacent flat hollow bodies and brazed to the flat hollow bodies are provided, and the flat hollow bodies have peripheral edges. 2. A swelling fluid passage and swelling header forming portions connected to both ends of the swelling fluid passage are provided between the two plates, and the heat exchanger component is a plate. 13. The heat exchanger according to any one of claims to 12. The heat exchanger according to claim 13 or 14, wherein a fluid containing an acidic component flows through at least one of a fluid passage in the flat hollow body and a gap between adjacent flat hollow bodies. The fuel hydrogen gas generated by the reforming in the fuel cell system flows through the gap between the adjacent flat hollow bodies, and the outer peripheral surface of the flat hollow body is covered with an Al-Si alloy layer. A fluoride layer is formed on a surface portion of the Si alloy layer, the Al-Si alloy layer has a portion having a Si content of 1.65% by mass or less, and an outer peripheral surface of the flat hollow body and a surface of the fin. The heat exchanger according to any one of claims 13 to 15, wherein a catalyst for selectively oxidizing CO is attached to the catalyst, and the catalyst reduces CO in the fuel hydrogen gas. A fuel cell system comprising the heat exchanger according to any one of claims 1 to 16 for reducing CO. A fuel cell vehicle equipped with the fuel cell system according to claim 17. A cogeneration system comprising the fuel cell system according to claim 17. A fluid passage forming bulge portion using a brazing sheet in which both surfaces of a core material made of pure aluminum or an aluminum alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy brazing, and a fluid passage A plate having a header-forming bulging portion that bulges out from the bulging portion for forming and that is continuous with both ends of the bulging portion for forming a fluid passage is formed. The two plates face each other with the openings of the bulging portions facing each other. Are stacked so that the bottom wall outer surfaces of the header-forming bulging portions abut against each other, and a pure plate is formed between a portion corresponding to the fluid-passage-forming bulging portion in an adjacent plate pair. Placing fins made of bare material of aluminum or aluminum alloy, brazing sheet for forming a plate by preheating a combination of plate pairs and fins Diffuse the Si in the skin material into the core material, braze the peripheral edges of both plates constituting the plate pair after preheating to form a flat hollow body, and braze the fins to the flat hollow body. After the brazing, the brazing body of the flat hollow body and the fins is heated in an atmosphere containing a fluoridation gas to form a fluoride layer on the surface of the flat hollow body and the surface of the fin. A method for manufacturing a heat exchanger. Both surfaces of a core material made of pure aluminum or an aluminum alloy are covered with a skin material made of Al-7.5 to 12.5 mass% Si alloy brazing, and a pure material is provided between at least one of the skin materials and the core material. Using a brazing sheet on which an intermediate layer made of aluminum is formed, a bulging portion for forming a fluid passage, and a bulging portion for forming a header that bulges out from the bulging portion for forming a fluid passage and are connected to both ends of the bulging portion for forming a fluid passage. A plate having a bulging portion is formed. A plate pair formed by combining two plates such that the openings of both bulging portions face each other is brought into contact with the bottom wall outer surface of the header forming bulging portion. And fins made of pure aluminum or an aluminum alloy bare material are arranged between the portions corresponding to the fluid passage forming bulges in adjacent plate pairs. A flat hollow body is formed by brazing the peripheral edges of both plates constituting the plate pair, and fins are brazed to the flat hollow body.After brazing, the brazed body of the flat hollow body and the fins is brazed. Forming a fluoride layer on the surface of the flat hollow body on the side where the intermediate layer is present and on the surface of the fin by heating in a fluoridation treatment atmosphere containing a fluoridation treatment gas. Method of manufacturing the vessel. 22. The method for manufacturing a heat exchanger according to claim 21, wherein a total of 0.1 to 0.25% by mass of Zr and / or Mg is added to pure aluminum constituting an intermediate layer of the brazing sheet forming the plate. 23. The method for manufacturing a heat exchanger according to claim 21, wherein the ratio of the thickness of the intermediate layer of the brazing sheet forming the plate is 5 to 25% based on 100% of the total thickness of the brazing sheet. The method for manufacturing a heat exchanger according to any one of claims 20 to 23, wherein the core material and the fins of the brazing sheet forming the plate are each made of a JIS A3003 alloy. The production of the heat exchanger according to any one of claims 20 to 24, wherein the ratio of the thickness of the skin material of the brazing sheet forming the plate is 2 to 25% with respect to the total thickness of the brazing sheet of 100%. Method. The fluoridation gas is at least one gas selected from the group consisting of a fluorine gas, a chlorine trifluoride gas and a nitrogen fluoride gas. The method for manufacturing a heat exchanger according to any one of claims 20 to 25, wherein a processing atmosphere is formed. The method for manufacturing a heat exchanger according to claim 26, wherein the concentration of the fluoridation gas in the fluoridation treatment atmosphere is 5 to 80%. The method for producing a heat exchanger according to claim 26, wherein the concentration of the fluoridation gas in the fluoridation treatment atmosphere is 10 to 60%. The method for manufacturing a heat exchanger according to any one of claims 20 to 28, wherein after forming the fluoride layer, a catalyst for selectively oxidizing CO is attached to an outer peripheral surface of the flat hollow body and a surface of the fin. The surface of the Al-Si alloy layer is covered with a component having a fluoride layer formed on the surface of the Al-Si alloy layer, and the Al-Si alloy layer of the component has a Si content. Pure aluminum or aluminum alloy products having a portion of not more than 1.65% by mass. The pure aluminum or aluminum alloy product according to claim 30, wherein the thickness of the fluoride layer is 2 nm to 10 m. The pure aluminum or aluminum alloy product according to claim 30 or 31, wherein the fluoride layer is made of a fluoride produced by fluorinating the surface of the Al-Si alloy layer of the constituent member. An anodic oxide film is formed on the surface of the Al-Si alloy layer of the component, a plating layer containing nickel is formed on the surface of the anodic oxide film, and a fluoride layer is formed on the surface of the plating layer. The pure aluminum or aluminum alloy product according to claim 30 or 31, wherein the fluoride layer is made of a fluoride produced by subjecting a surface of the plating layer to a fluorination treatment. On the surface of the fluoride layer, at least one laminated group composed of a nickel-containing plating layer and a fluoride layer made of fluoride generated by subjecting the surface of the plating layer to fluorination is formed. A pure aluminum or aluminum alloy product according to any one of claims 30 to 33. The constituent members consist of a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer. Si from the Al-Si alloy layer is diffused into the core layer, and each Al-Si alloy The pure aluminum or aluminum alloy product according to any one of claims 30 to 34, wherein the layer has a portion having a Si content of 1.65% by mass or less. The pure aluminum or aluminum alloy product according to claim 35, wherein at least one surface of the component is exposed to a fluid containing an acidic component or an alkaline component. The constituent member has a portion composed of a core layer made of pure aluminum or an aluminum alloy and an Al-Si alloy layer covering both surfaces of the core layer, and a portion between one of the Al-Si alloy layer and the core layer is provided. An intermediate layer made of pure aluminum is formed on the intermediate layer, Si from the Al—Si alloy layer is diffused into the intermediate layer, and the Al—Si alloy layer on the side where the intermediate layer is formed has an Si content of 1%. The pure aluminum or aluminum alloy product according to any one of claims 30 to 34, wherein the product has a portion of 0.65% by mass or less. The constituent member comprises a core layer made of pure aluminum or an aluminum alloy, and an Al-Si alloy layer covering both surfaces of the core layer, and an intermediate layer made of pure aluminum is provided between both the Al-Si alloy layer and the core layer. Is formed, and Si from the Al-Si alloy layer is diffused into each intermediate layer, and each Al-Si alloy layer has a portion having a Si content of 1.65% by mass or less. Item 34. A pure aluminum or aluminum alloy product according to any one of Items 30 to 34. The pure aluminum or aluminum alloy product according to claim 37 or 38, wherein Zr and / or Mg are added to the pure aluminum constituting the intermediate layer in a total amount of 0.1 to 0.25% by mass. The pure aluminum or aluminum alloy product according to any one of claims 37 to 39, wherein a ratio of a thickness of the intermediate layer is 5 to 25% with respect to 100% of a total thickness of the component. 41. The pure aluminum or aluminum alloy product according to any one of claims 37 to 40, wherein a surface of the component on the side where the intermediate layer is present is exposed to a fluid containing an acidic component or an alkaline component.

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