JP2005257257A - Heat exchanger and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an Al-made heat exchanger capable of keeping satisfactory corrosion resistance for a long period and preventing fin peeling or pitting. <P>SOLUTION: This method comprises steps of performing a flame coating treatment to the surface of an Al-made flat tube core material to form a Zn flame coating layer with a Zn adhesion quantity of 1-10 g/m<SP>2</SP>, thereby obtaining a heat exchanger tube 2; alternately arranging the heat exchanger tube 2 and an Al-made fin 3, and combining and connecting an Al-made header 4 to the end part of the heat exchanger tube 2 in a conducted and connected state by welding, thereby obtaining a heat exchanger core; and performing a formation treatment to the surface of the heat exchanger core by use of at least one kind of formation treatment agents selected from phosphoric acid chromates, chromic acid chromates, zirconium phosphate series, titanium phosphate series, zirconium fluoride series and titanium fluoride series to form a chemical formation treatment coating (anticorrosive coating). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an aluminum heat exchanger used in, for example, a refrigeration cycle for a car air conditioner and a method for manufacturing the same.

  In this specification, the term “aluminum” is used to include aluminum and its alloys.

  As an aluminum heat exchanger used in refrigeration cycles for car air conditioners, multiple flat tubes are stacked in the thickness direction with fins interposed between them, and hollow headers are connected to both ends of these tubes. A multiflow type or parallel flow type heat exchanger having a configuration is well known. In such a heat exchanger, for example, fins and headers are composed of an aluminum brazing sheet clad with a brazing material, and the whole is connected and integrated by being brazed together in a furnace in a temporary assembly state. It is what is done.

  In such an aluminum heat exchanger, as a technique for improving corrosion resistance, a technique for forming a sacrificial corrosion layer on a heat exchanger tube is often used.

  For example, the technique shown in Patent Document 1 below forms a sacrificial corrosion layer by spraying Zn on the surface of a heat exchanger tube and diffusing Zn on the surface of the tube.

On the other hand, in addition to the above-described Zn spraying treatment, as a technique for improving the corrosion resistance, as shown in Patent Documents 2 and 3, the surface of an aluminum product such as a heat exchanger is subjected to chemical conversion treatment to form a corrosion resistant coating. What was formed is also adopted.
JP-A-4-15496 (page 1, right column, lines 1-4) JP-A-11-131254 (Claim 1) Patent No. 3437023 (Claim 1)

  As shown in Patent Document 1, in the technique of spraying Zn on the surface of the heat exchanger tube, when Zn is sprayed on the tube surface, if the amount of Zn deposited is increased, the solder between Zn and the tube and the fin A large amount diffuses in the attaching portion (fillet), and the fillet is preferentially corroded, thereby causing a so-called fin peeling in which the fin peels off the tube. Accordingly, it is preferable to reduce the amount of Zn deposited, but since the thermal spraying of Zn on the low amount side becomes unstable, the amount of deposited particles varies, and a stable sacrificial corrosion layer is obtained over the entire sprayed region. However, there are problems such as pitting corrosion due to partial progress of corrosion due to long-term use.

  In addition, as shown in Patent Documents 2 and 3, in the technology for forming a corrosion-resistant film by chemical conversion treatment on the surface of the heat exchanger, a uniform corrosion-resistant film can be formed over a wide range, but the corrosion resistance should be maintained for a long time. There is a problem that the occurrence of pitting corrosion cannot be effectively prevented.

  The present invention eliminates the above-mentioned problems of the prior art, can maintain good corrosion resistance for a long period of time, and can reliably prevent the occurrence of fin peeling, pitting corrosion, and the like, and a method for manufacturing the same The purpose is to provide.

  In order to achieve the above object, the present invention has the following structure.

[1] A step of applying a thermal spraying treatment to a flat tube core made of aluminum to form a Zn sprayed layer having a Zn deposition amount of 1 to 10 g / m ² to obtain a heat exchanger tube;
The heat exchanger tubes and the aluminum fins are alternately laminated and combined, and an aluminum header is connected to the end of the heat exchanger tube in a state where the aluminum headers are connected to each other by brazing and joining. Obtaining a core;
At least one chemical conversion treatment agent selected from among phosphate chromate, chromate chromate, zirconium phosphate, titanium phosphate, zirconium fluoride, and titanium fluoride is used on the surface of the heat exchanger core. And a chemical conversion treatment to form a chemical conversion coating (corrosion resistant coating).

  In the manufacturing method of this invention, since the amount of Zn deposited on the tube is low, Zn does not diffuse in a large amount into the fillet, preferential corrosion of the fillet can be prevented, and fin peeling can be reliably prevented. . Furthermore, even if there is some variation in the sacrificial corrosion layer due to low Zn spraying, a uniform corrosion-resistant film can be formed on the core surface over a wide range by chemical conversion treatment, so that it can be applied to core components such as tubes and fins. The erosion can be surely delayed, the corrosion resistance of the tube or the like can be maintained for a long time, and the occurrence of pitting corrosion can be effectively prevented. In addition, the durability of the corrosion can be drastically improved because the corrosion life is additionally extended by the corrosion-resistant film and the sacrificial corrosion layer. Thus, the sacrificial corrosion layer by low Zn spraying and the corrosion-resistant film by chemical conversion treatment exhibit synergistic effects while compensating for each other's defects, and good corrosion resistance can be obtained over a long period of time.

  In the present invention, when the following configurations [2] to [9] are adopted, the above-described effects can be obtained more reliably.

  [2] The method for producing an aluminum heat exchanger as recited in the aforementioned Item 1, wherein a chemical etching treatment is performed before the chemical conversion treatment is performed on the heat exchanger core.

  [3] The method for producing an aluminum heat exchanger as recited in the aforementioned Item 2, wherein a pickling treatment using an acidic solution is used as the chemical etching treatment.

[4] The method for producing an aluminum heat exchanger as described in any one of 1 to 3 above, wherein the Zn adhesion amount in the thermal spraying treatment is adjusted to ² to 6 g / m ² .

  [5] The method for manufacturing an aluminum heat exchanger according to any one of items 1 to 4, wherein the chemical conversion treatment is performed using a zirconium fluoride-based chemical conversion treatment agent.

[6] The method for producing an aluminum heat exchanger as recited in the aforementioned Item 5, wherein the adhesion amount of zirconium in the chemical conversion treatment is adjusted to 30 to 200 mg / m ² .

  [7] The aluminum heat exchanger as described in any one of 1 to 6 above, wherein 0.2 to 0.6% by mass of Cu and 0.1 to 2% by mass of Mn are added to the tube core material. Manufacturing method.

  [8] The aluminum heat described in any one of 1 to 7 above, wherein the fin includes an aluminum fin core material, and the fin core material contains 0.8 to 3% by mass of Zn. Exchanger manufacturing method.

  [9] The aluminum heat exchanger as described in any one of 1 to 8 above, wherein an area ratio of a region covered with Zn on a surface of the heat exchanger tube is adjusted to 10 to 90% or more. Production method.

  In the following heat exchangers [10] and [11], since one embodiment of the heat exchanger obtained by the above-described manufacturing method invention is specified, the same effects as described above can be obtained.

  [10] An aluminum heat exchanger manufactured by the manufacturing method described in any one of 1 to 9 above.

[11] A heat exchanger tube in which a Zn sprayed layer having a Zn deposition amount of 1 to 10 g / m ² and aluminum fins are alternately stacked on a flat tube core made of aluminum, A heat exchanger core brazed and joined in a state in which an aluminum header is connected in communication with the end of the heat exchange tube;
On the surface of the heat exchanger core, at least one chemical conversion coating film selected from among phosphate chromate, chromate chromate, zirconium phosphate series, titanium phosphate series, zirconium fluoride series, and titanium fluoride series ( An aluminum heat exchanger characterized in that a corrosion-resistant film is formed.

[12] A refrigeration cycle in which the refrigerant compressed by the compressor is condensed by the condenser, the condensed refrigerant is passed through the decompressor to reduce the pressure, and the decompressed refrigerant is evaporated by the evaporator and returned to the compressor. Because
The said condenser is comprised with the aluminum heat exchanger of Claim 10 or 11, The refrigeration cycle characterized by the above-mentioned.

  In this refrigeration cycle, similar effects can be obtained as described above.

  As described above, according to the present invention, it is possible to provide an aluminum heat exchanger that can maintain good corrosion resistance for a long period of time and can reliably prevent the occurrence of fin peeling, pitting corrosion, and the like, and a method for manufacturing the same. .

  FIG. 1 is a front view showing an aluminum heat exchanger (1) according to an embodiment of the present invention. As shown in the figure, the heat exchanger (1) is used as a condenser for a refrigeration cycle in an automobile air conditioner, and constitutes a multiflow type heat exchanger.

  This heat exchanger (1) has a plurality of flat heat exchanger tubes along the horizontal direction as a heat exchange line between a pair of hollow headers (4) and (4) along the vertical direction arranged in parallel. (2) is arranged in parallel in the vertical direction with both ends communicating with both hollow headers (4) and (4), and between these tubes (2) and the outermost tube (2). The corrugated fin (3) is disposed outside the outer side, and the side plate (10) is disposed outside the outermost corrugated fin (3).

  In this heat exchanger (1), a tube (2) made of aluminum (including an alloy thereof) sprayed with a low amount of Zn is used, and a fin (3) and a header (4) are used as fins. An aluminum brazing sheet in which a brazing material is clad on at least one side of the core material is used. Then, after temporarily assembling the tube (2), fin (3), header (4) and side plate (10) into a heat exchanger shape, the temporarily assembled product is collectively brazed in the furnace. The whole is joined and integrated, and the heat exchanger core is manufactured.

  Further, the heat exchanger core is subjected to a chemical conversion treatment which will be described later, and a corrosion-resistant film is formed over the entire surface.

  First, as shown in FIG. 2, the tube (2) uses an extruded product of an aluminum material as a tube core material, and a sprayed layer (20) containing Zn is formed on at least one surface of the core material.

  As the core material of the tube (2), a material made of an Al alloy to which Cu and Mn are added can be suitably used.

  Here, in the present embodiment, the addition amount of Cu in the tube core material may be adjusted to 0.2 to 0.6% by mass (including the upper limit value and the lower limit value, and the same applies to others), and more preferably. It is good to adjust to 0.25-0.5 mass%. Further, the amount of Mn added is preferably adjusted to 0.1 to 2% by mass, more preferably 0.1 to 0.5% by mass or 0.6 to 1.5% by mass. That is, when the added amount of Cu or the added amount of Mn is too small, the potential of the tube core material is not noble with respect to the peripheral portion, the corrosion to the core material is likely to proceed, and pitting corrosion occurs. There is a fear. Moreover, when there is too much addition amount of Cu, there exists a possibility that corrosion resistance may fall by the intergranular corrosion of Cu. Further, when the amount of Mn added is too large, the molding material may be increased in strength and strength at the time of processing the tube core material such as extrusion, so that the workability such as extrudability may be deteriorated.

  In the present embodiment, the tube core material is formed by extruding the Al alloy material.

  The thermal spray layer (20) as a sacrificial corrosion layer is formed by thermally spraying and adhering Zn to the surface of the tube core material, and diffusing the Zn into the tube core material by heating during brazing. .

  The method for spraying Zn on the surface of the tube core material is not particularly limited, but it is preferable to use arc spraying. For example, a method in which a spray gun of an arc sprayer is scanned with respect to the tube core material, a method in which the core material wound in a coil shape is sprayed while rewinding, or when the tube core material is an extruded material, an extrusion die is used. Immediately after that, a spray gun is disposed, and a method of continuously performing extrusion and spraying can be employed. In particular, when extrusion and thermal spraying are continuously performed, production efficiency can be improved.

  The sprayed layer (20) may be formed only on one side of the tube core material, or may be formed on both upper and lower sides. Needless to say, when forming the sprayed layers (20) on both sides of the tube, it is preferable to arrange spray guns on both the upper and lower sides of the tube core.

  Further, the thermal spraying treatment is performed in an inert gas atmosphere (non-oxidizing atmosphere) such as nitrogen gas in order to prevent oxidation of the thermal spray layer (20) formed on the surface of the aluminum material (tube core material) as much as possible. Is good.

Zn deposition amount of the tube (2) in the spraying process, it is necessary to adjust the 1 to 10 g / m ² to a low amount range. That is, when the amount of Zn deposited is too small, a sacrificial corrosion layer due to Zn deposition cannot be sufficiently formed, and desired corrosion resistance may not be obtained. On the other hand, when the Zn adhesion amount is too large, Zn diffuses in the fillet between the tube and the fin so that the fillet is preferentially corroded and the fin may be peeled off.

  The ratio of the sprayed area to the entire surface of the tube is preferably set to 10 to 90%, more preferably 20 to 80%. That is, when the area ratio is too small, the Zn-containing region decreases, and a sufficiently large sacrificial corrosion layer cannot be formed, making it difficult to obtain good corrosion resistance. On the other hand, when the amount is too large, a large amount of Zn diffuses into the fillet and fin peeling may occur, which is not preferable.

  Needless to say, the sprayed metal material may contain a small amount of other elements as inevitable impurities so as not to affect the sprayed metal material.

  On the other hand, the Zn content in the fin core material of the corrugated fin (3) is preferably adjusted to 0.8 to 3% by mass, more preferably 2 to 2.8% by mass. That is, when the Zn content is too small, the potential of the fin core material becomes noble with respect to the brazing material and the like, and the fillet is preferentially corroded, and there is a possibility that the fin peels off. On the other hand, if the Zn content is too high, the corrosion resistance of the fin core material itself is lowered and corroded early, which may cause a decrease in heat transfer performance and the like, which is not preferable.

  In this embodiment, in addition to the heat exchanger tube (2), the corrugated fin (3), and the hollow header (4), a number of heat exchanger components such as the side plate (10) are used for heat exchange. Temporarily assembled into a bowl shape. After that, the flux is applied to the temporary assembly product and dried, and then the temporary assembly product is heated in a heating furnace in a nitrogen gas atmosphere. Are integrated to produce a heat exchanger core.

  Furthermore, in this embodiment, a chemical conversion treatment is performed on the heat exchanger core. In the chemical conversion treatment, using at least one chemical conversion treatment agent selected from among phosphate chromate, chromate chromate, zirconium phosphate series, titanium phosphate series, zirconium fluoride series, titanium fluoride series, A chemical conversion treatment film (corrosion resistance film) is formed on the surface of the heat exchanger core.

  For example, the heat exchanger core is immersed in the chemical conversion treatment agent (immersion method), or the chemical conversion treatment agent is sprayed onto the surface of the heat exchanger core (spray method) to apply the chemical conversion treatment agent to the heat exchanger. A film of the treating agent component (chemical conversion film) is formed on the surface in contact with the surface of the core.

  In the chemical conversion treatment of the present embodiment, it is preferable to use a zirconium fluoride-based temporary treatment agent in consideration of corrosion resistance and environmental problems.

When chemical conversion treatment is performed with a zirconium fluoride-based temporary treatment agent, the amount of zirconium deposited is preferably adjusted to 30 to 200 mg / m ² , more preferably 60 to 180 mg / m ² . That is, if the amount of zirconium deposited is too small, sufficient corrosion resistance cannot be obtained. Conversely, if the amount of deposited zirconium is too large, an effect commensurate with that cannot be obtained, and this is industrially uneconomical. It is not preferable.

  In this embodiment, it is preferable to perform a chemical etching process on the heat exchanger core before performing the chemical conversion process. As the chemical etching treatment, it is preferable to perform a pickling treatment using an acidic solution. An etching solution such as an acidic solution may be brought into contact with the heat exchanger core using an immersion method, a spray method, or the like, similar to the chemical conversion treatment.

  The heat exchanger of the present embodiment obtained by the above procedure has a corrosion resistance by chemical conversion treatment on a heat exchanger core assembled using a heat exchanger tube (low Zn sprayed tube) in which a low amount of Zn is sprayed. Since it forms a film, good corrosion resistance can be obtained over a long period of time. That is, since the sacrificial corrosion layer is formed based on the sprayed layer containing a low amount of Zn, Zn does not diffuse in a large amount into the fillet, and fin peeling due to preferential corrosion of the fillet can be prevented. Furthermore, even if there is some variation in the sacrificial corrosion layer due to low Zn spraying, a uniform corrosion-resistant film can be formed on the core surface over a wide range by chemical conversion treatment, so that the core components such as tubes and fins are eroded. The corrosion resistance of the tube or the like can be sufficiently maintained for a long period of time, and the occurrence of pitting corrosion can be effectively prevented. In addition, the durability of the corrosion can be drastically improved because the corrosion life is additionally extended by the corrosion-resistant film and the sacrificial corrosion layer. In this way, the sacrificial corrosion layer by low Zn spraying and the corrosion resistant coating by chemical conversion treatment exhibit synergistic effects while compensating for each other's defects, thereby preventing corrosion degradation such as fin peeling and pitting corrosion over a long period of time. Good corrosion resistance can be obtained.

  Examples related to the present invention and comparative examples for verifying the effects will be described below.

<Example 1>
A porous flat tube core material having a width of 16 mm, a height of 3 mm, and a thickness of 0.5 mm by an extruder using an extruded material made of an Al alloy (containing 0.4 mass% Cu, 0.15 mass% Mn, and the balance Al). While extrusion molding was performed, spray guns of an arc sprayer were placed above and below the exit of the extruder, and Zn was sprayed on both the top and bottom surfaces of the extruded tube to form a sprayed layer. Thereafter, the sprayed tube (heat exchanger tube) was cooled in a cooling water tank and then wound into a coil.

As shown in Table 1 below, in the above thermal spraying process, the amount of deposited Zn was adjusted to 1 g / m ² .

  Furthermore, the heat exchanger of the same structure as the multiflow type heat exchanger (refer FIG. 1) shown to the said embodiment was assembled in the temporary assembly state using said heat exchanger tube.

  After that, a suspension in which the flux is suspended in water is applied to the heat exchanger temporary assembly product by spraying and dried, and then heated in a heating furnace under a nitrogen gas atmosphere at 600 ° C. for 10 minutes, The whole was joined and integrated by brazing to obtain a heat exchanger core.

  Subsequently, the heat exchanger core was pickled using a pickling detergent (nitric acid 10 mass% + sulfuric acid 5 mass% + iron 1 mass%, where iron exists as an iron salt). Thereafter, chemical conversion treatment was performed using a zirconium-based chemical conversion treatment agent (zirconium fluoride-based chemical conversion treatment agent). At this time, as the chemical conversion treatment agent, an aqueous medium containing zirconium ions at a concentration of 100 ppm is used, and the heat exchanger core is immersed for 90 seconds in a bath heated to 50 ° C. The chemical conversion treatment was performed under the conditions Thereafter, the heat exchanger core was sufficiently washed with tap water to obtain a heat exchanger sample of Example 1.

<Examples 2 to 6>
As shown in Table 1 above, heat exchanger samples were prepared in the same manner as described above except that the Zn deposition amount in the thermal spraying treatment was 2, 4, 6, 8, 10 g / m ² .

<Examples 7 to 9>
As shown in Table 1 above, samples were prepared in the same manner as above except that the Zn deposition amount in the thermal spraying treatment was 3, 4, 7 g / m ² and a titanium fluoride chemical conversion treatment agent was used as the chemical conversion treatment agent. did. In addition, as a chemical conversion treatment agent, the said heat exchanger core is immersed for 90 second in the bath which heated the treatment agent to 50 degreeC using what contained the titanium ion in the density | concentration of 100 ppm in the aqueous medium. Chemical conversion treatment was performed under conditions.

<Examples 10 to 12>
As shown in Table 1 above, the Zn adhesion amount in the thermal spraying treatment is ² , 5, 8 g / m ^2, and the phosphoric acid chromate chemical conversion treatment agent (“Alsurf 407/47” manufactured by Nippon Paint Co., Ltd.) is used as the chemical conversion treatment agent. A sample was prepared in the same manner as described above except that it was used.

<Examples 13 to 16>
As shown in Table 1 above, the Zn deposition amount in the thermal spraying treatment is 1, 3, 6, 10 g / m ^2, and chromic chromate chemical conversion treatment agent (“Alsurf 600LN2” manufactured by Nippon Paint Co., Ltd.) is used as the chemical conversion treatment agent. A sample was prepared in the same manner as described above except that it was used.

<Comparative Example 1>
As shown in Table 2 below, the amount of Zn deposited in the thermal spraying process was excessively reduced to 0.5 g / m ² and the same treatment as in the above example was performed except that the zirconium fluoride-based chemical conversion treatment agent was used as the chemical conversion treatment agent. A heat exchanger sample was prepared.

<Comparative example 2>
As shown in Table 2 above, a heat exchanger sample was produced in the same manner as in Comparative Example 1 except that the Zn deposition amount in the thermal spraying process was excessively increased to 12 g / m ² .

<Comparative Example 3>
As shown in Table 2 above, a sample was prepared in the same manner as described above except that the Zn adhesion amount in the thermal spraying process was excessively increased to 11 g / m ² and the above-described phosphate chromate chemical conversion treatment agent was used as the chemical conversion treatment agent. .

<Comparative example 4>
As shown in Table 2 above, a sample was prepared in the same manner as described above except that a chromic acid chromate chemical conversion treatment agent was used as a chemical conversion treatment agent without performing thermal spraying.

<Comparative Example 5>
As shown in Table 2 above, a sample was prepared in the same manner as described above, with the Zn adhesion amount in the thermal spraying treatment set to 3 g / m ² and without performing chemical conversion treatment.

<Comparative Example 6>
As shown in Table 2 above, a sample was prepared in the same manner as described above, with the Zn adhesion amount in the thermal spraying treatment set to 5 g / m ² and without performing chemical conversion treatment.

<Comparative Example 7>
As shown in Table 2 above, the Zn deposition amount in the thermal spraying process was excessively increased to 12 g / m ^2, and a sample was prepared in the same manner as described above without performing the chemical conversion treatment.

<Evaluation test>
The following CCT and SWAAT tests were performed on the heat exchanger samples of the above examples and comparative examples, and the corrosion state was investigated.

<CCT (combined cycle corrosion test)>
A cycle of spraying a corrosion test solution made of 5% NaCl aqueous solution for 1 hour, drying for 2 hours, and then leaving it in a wet state for 21 hours was performed as 180 cycles.

  Then, for each sample, the maximum corrosion depth is measured, “◎” when the maximum corrosion depth is less than 150 μm, “○” when the maximum corrosion depth is 150 μm or more and less than 200 μm, and the maximum corrosion depth. Was evaluated as “Δ” when the thickness was 200 μm or more and less than 250 μm, and “X” when the maximum corrosion depth was 250 μm or more. The results are also shown in Tables 1 and 2 above.

<SWAAT (Synthetic sea water Acetic Acid salt spray Test)>
A cycle of spraying a corrosion test solution according to ASTM-D1141 for 0.5 hours and leaving it in a wet state for 1.5 hours was repeated for 960 hours.

  For each sample, the fin joint remaining rate after the corrosion test is measured, and the fin joint remaining rate after the corrosion test is 95% or more, and the fin joint remaining rate after the corrosion test is 70% or more. , Less than 95% is "O", fin joint residual rate after corrosion test is 50% or more and less than 70% "△", fin joint residual rate after corrosion test is less than 50% " “×” was evaluated. The results are also shown in Table 1 below. The fin remaining rate after the corrosion test is a percentage of the sample tube and the fin joined after the corrosion test with respect to the sample before the corrosion test.

As is clear from the above test results, it can be seen that in the heat exchangers of the examples related to the present invention, satisfactory results are obtained in CCT and SWAAT, and the corrosion resistance is excellent. In particular, those having a small amount of Zn deposition of 6 g / m ² or less in the thermal spraying treatment have better corrosion resistance.

  On the other hand, in the heat exchanger of a comparative example, it turns out that the result of at least one of CCT and SWAAT is inadequate, and it is inferior to corrosion resistance. Actually, in the heat exchanger of the comparative example, many fin peeling and pitting corrosion were observed.

  The present invention is applicable to an aluminum heat exchanger used in a refrigeration cycle for a car air conditioner and a method for manufacturing the same.

It is a front view which shows the aluminum heat exchanger which is embodiment of this invention. It is a perspective view which expands and shows the junction part periphery of the tube and fin in the heat exchanger of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Heat exchanger 2 ... Tube 3 ... Corrugated fin 4 ... Hollow header 20 ... Thermal spray layer

Claims (12)

Applying a thermal spraying treatment to the flat tube core material made of aluminum to form a Zn sprayed layer having a Zn deposition amount of 1 to 10 g / m ² to obtain a heat exchanger tube;
The heat exchanger tubes and the aluminum fins are alternately laminated and combined, and an aluminum header is connected to the end of the heat exchanger tube in a state where the aluminum headers are connected to each other by brazing and joining. Obtaining a core;
At least one chemical conversion treatment agent selected from among phosphate chromate, chromate chromate, zirconium phosphate, titanium phosphate, zirconium fluoride, and titanium fluoride is used on the surface of the heat exchanger core. And a chemical conversion treatment to form a chemical conversion coating (corrosion resistant coating).   The method for producing an aluminum heat exchanger according to claim 1, wherein a chemical etching treatment is performed before the chemical conversion treatment is performed on the heat exchanger core.   The method for producing an aluminum heat exchanger according to claim 2, wherein a pickling treatment using an acidic solution is used as the chemical etching treatment. The manufacturing method of the aluminum heat exchanger as described in any one of Claim 1 thru | or 3 by which Zn adhesion amount in the said thermal spraying process is adjusted to 2-6 g / m < ² >.   The method for producing an aluminum heat exchanger according to any one of claims 1 to 4, wherein the chemical conversion treatment is performed using a zirconium fluoride-based chemical conversion treatment agent. The method for producing an aluminum heat exchanger according to claim 5, wherein the amount of zirconium deposited in the chemical conversion treatment is adjusted to 30 to 200 mg / m ² .   The manufacture of an aluminum heat exchanger according to any one of claims 1 to 6, wherein 0.2 to 0.6 mass% Cu and 0.1 to 2 mass% Mn are added to the tube core material. Method.   The aluminum heat exchanger according to any one of claims 1 to 7, wherein the fin includes an aluminum fin core material, and the fin core material contains 0.8 to 3% by mass of Zn. Manufacturing method.   The method for producing an aluminum heat exchanger according to any one of claims 1 to 8, wherein an area ratio of a region covered with Zn on a surface of the heat exchanger tube is adjusted to 10 to 90%.   An aluminum heat exchanger manufactured by the manufacturing method according to claim 1. A heat exchanger tube in which a Zn sprayed layer having a Zn deposition amount of 1 to 10 g / m ² is formed on an aluminum flat tube core material and aluminum fins are alternately stacked, and the heat exchange tube A heat exchanger core brazed and joined in a state in which an aluminum header is connected in communication with the end of
On the surface of the heat exchanger core, at least one chemical conversion coating film selected from phosphate chromate, chromate chromate, zirconium phosphate, titanium phosphate, zirconium fluoride, and titanium fluoride ( An aluminum heat exchanger characterized in that a corrosion-resistant film is formed. A refrigerant cycle in which refrigerant compressed by a compressor is condensed by a condenser, the condensed refrigerant is passed through a decompressor to reduce pressure, and the decompressed refrigerant is evaporated by an evaporator and returned to the compressor. ,
The said condenser is comprised with the aluminum heat exchanger of Claim 10 or 11, The refrigeration cycle characterized by the above-mentioned.

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