JP4805280B2 - Method for sealing pores of anodized aluminum phosphate - Google Patents

Abstract

Process of seal coating phosphoric acid anodized aluminum and aluminum alloys to improve the corrosion resistance and maintain the adhesive bonding properties. The process comprises post-treating phosphoric acid anodized aluminum and its alloys with an acidic aqueous solution comprising, per liter of acidic solution, from about 0.01 to 22 grams of a water soluble trivalent chromium compound, about 0.01 to 12 grams of an alkali metal hexafluorozirconate, about 0.0 to 12 grams of at least one alkali metal tetrafluorosilicate and/or an alkali metal hexafluoroborate, from about 0.001 to 10 grams of at least one water soluble divalent zinc compound and from 0.0 to 10 grams of a water soluble thickener and/or water soluble surfactant.

Description

(Statement of government relations)
The present invention was made by a United States government employee, which is manufactured or used for governmental purposes by the United States government and does not incur any royalty payments for the product or its use.

  The present invention relates to a processing method for forming a thin film or coating on phosphoric acid anodized aluminum and its alloys. The coating system includes anodized aluminum phosphate, an additional post-treatment or sealing coating, preferably an adhesive-bonded primer or other additional coating. Phosphoric acid anodized aluminum coating is very porous and therefore has poor corrosion resistance. However, this coating has excellent adhesion. Thus, the anodized film can be useful by applying a post-treatment or sealing film that enhances corrosion resistance so as not to interfere with adhesion. Due to the performance and features of the present invention, phosphoric acid anodized film is used for unpainted applications that are not currently in practical use, chromic acid anodized aluminum and FPL etching (both containing chromic acid) that are easily corroded Can be used for applications, all adhesive bonding applications replaced with the use of non-chromic binding primers, and general applications that can reduce coating wear and weight compared to other anodized coatings .

  The present invention relates to a treatment method for maintaining and improving the corrosion resistance of anodized aluminum phosphate. In particular, the present invention relates to a sealing treatment method for anodized aluminum phosphate and an anodized aluminum alloy. The trivalent chromium post-treatment (TCP) treatment method includes an effective amount of at least one water-soluble trivalent chromium compound, alkali metal hexafluoride zirconate, at least one alkali metal tetrafluoroborate and / or six. An acidic aqueous solution containing a fluorosilicate, at least one divalent zinc compound, and an effective amount of a water-soluble thickener and / or a water-soluble surfactant.

  Anodized aluminum is typically sealed or post-treated after anodization by a variety of sealing processes and processing methods using compositions. The high-performance post-processing method or sealant applied to the current anodized aluminum is based on chemical treatment using hexavalent chromium. Hexavalent chromium is extremely toxic and is known to have carcinogenicity. Therefore, the solution used for forming these protective films and the coating itself are toxic. However, this thin film or coating has good adhesion and improves the corrosion resistance of anodized aluminum. Typically, the sealing film is formed on the anodized film by raising the temperature, and is usually applied by a dipping or spraying method. Post-treatment may be required for military or commercial specifications, and the coating applied in each may be different. That is, as in the case of an aluminum conversion coating, there is not only one “post-treatment” specification for all anodized aluminum.

  Also, due to environmental laws, administrative orders and local health and safety (OSH) regulations, military and commercial users are exploring treatment methods that do not use hexavalent chromium. In the case of anodized aluminum, the anodized film and substrate metal are relatively harmless. However, if further hexavalent chromium treatment is required, these coatings become toxic. Although other compositions used for anodized aluminum coatings do not contain hexavalent chromium, their technical performance is inferior to coatings using hexavalent chromium. Furthermore, the use of hexavalent chromium is becoming more expensive as regulations become stricter. If restrictions are imposed by EPA (Economic Partnership Agreement) in the future, it may become unavailable due to high costs. In this way, the existing hexavalent chromium treatment has excellent technical performance in terms of providing excellent corrosion resistance and adhesive bondability with a coating such as a paint at a low cost. And from the OSH perspective, hexavalent chromium coatings are harmful to both humans and the environment.

  With regard to adhesive bonding, phosphoric acid anodization has been introduced as an alternative to chromic acid anodization. Phosphoric acid anodic oxide coating provides excellent adhesive bonding performance, but cannot sufficiently prevent corrosion of the aluminum layer. Normally, anodizing sealant is applied to various other anodic oxide coatings to improve the corrosion resistance, but in the case of phosphoric acid anodic oxide coatings, it is not generally applied because adhesive bond performance is significantly reduced. . As a result, the corrosion resistance treatment of the phosphoric acid anodized film is performed by a chromic acid binding primer or a general-purpose primer. The phosphoric acid anodized film has a columnar structure and is porous, which improves the adhesive bonding performance. However, since the columnar and porous structures simultaneously improve the corrosivity, it is difficult to prevent corrosion, particularly with a phosphoric acid anodized film. For example, a phosphoric acid-anodized “honeycomb” structure core material widely used in military aircraft will corrode immediately during use if the protective coating is damaged, so that the adhesive bond performance of the anodized coating will not be adversely affected. Corrosion resistant sealants can be useful.

  The present invention relates to a post-treatment or sealing treatment method for anodized aluminum phosphate and its alloys at room temperature or higher, ie, about 93 ° C. (200 ° F.) or less. More specifically, the present invention relates to a post-treatment method for anodized aluminum phosphate and alloys thereof for improving corrosion resistance and maintaining adhesive bondability such as paint adhesion. The trivalent chromium post-treatment (TCP) composition of the present invention comprises an acidic aqueous solution having a pH of about 2.5 to 5.5, preferably 2.5 to 4.5, 3.4 to 4.0. About 0.01-22 grams of water-soluble trivalent chromium composition per liter, about 0.01-12 grams of alkali metal hexafluoride zirconate, about 0.0-12 or 0.001-12 grams At least one fluorine compound selected from the group consisting of alkali metal tetrafluoroborate, alkali metal hexafluorosilicate, various combinations or mixtures in any proportion, 0.001-10 grams of water-soluble divalent zinc Compound, 0-10 grams, preferably 0-2 grams of at least one water-soluble thickener, 0-10 grams, preferably 0-2.0 grams of at least one water-soluble nonionic, cation And anionic surfactant The other includes a humectant.

  Thus, the present invention provides a trivalent chromium compound, an alkali metal hexafluoride zirconate, a boron tetrafluoride used in a treatment for maintaining the adhesion of anodized aluminum phosphate and its alloys and improving the corrosion resistance. An acidic aqueous solution comprising an acid salt and / or hexafluorosilicate is provided.

  Another object of the present invention is to provide an effective amount of trivalent chromium salt and hexafluorozirconate in the range of about 2.5 to 5.5 for sealing aluminum phosphate anodized aluminum and its alloys. It is to provide a stable acidic aqueous solution having a pH.

  Furthermore, the present invention provides a stable acidic aqueous solution having a pH in the range of about 3.7 to 4.0 for sealing pores of anodized aluminum phosphate and its alloys at temperatures above room temperature. An acidic aqueous solution containing chromium salt and hexafluorozirconate and substantially free of hexavalent chromium is provided.

  These and other objects of the present invention will become apparent by reference to the detailed description taken in conjunction with the accompanying FIGS.

  More specifically, the present invention relates to an acidic aqueous solution having a pH in the range of about 2.5 to 5.5, preferably a pH in the range of about 2.5 to 4.5 or 3.7 to 4.0. The present invention relates to a treatment method for sealing anodized aluminum phosphate and an alloy thereof using, to maintain the adhesive bondability of the anodized aluminum and to improve the corrosion resistance. The treatment method is about 0.01-22 grams, preferably about 4.0-8.0 grams, such as 6 grams of at least one water-soluble trivalent chromium composition, about 0.01-12 grams, preferably 6.0 to 12 grams, such as 8.0 grams of at least one alkali metal hexafluoride zirconate salt, about 0.0 to 12 or about 0.001 to 12 grams, preferably about 0.12 Selected from -1.2 grams, such as 0.24-0.36 grams of at least one alkali metal tetrafluoroborate, alkali metal hexafluorosilicate, and various combinations or mixtures of any proportions At least one fluorine compound and at least one water-soluble divalent zinc compound such as 0.001 to 10 grams, preferably 0.1 to 5.0 grams or 1.0 to 2.0 grams zinc sulfate. Using acidic aqueous solution Including that.

  In certain treatments, depending on the physical properties of the anodized aluminum phosphate (eg, the physical size of the anodized layer, etc.), a thickener may be added to the solution to reduce solution evaporation, spraying and coating In some cases, the formation of an optimum thin film during the process is assisted. This also makes it difficult to form powders that reduce paint adhesion. Furthermore, the addition of the thickening agent helps to form an appropriate thin film in application to a large area, and has a function of reducing the dilution effect of the cleaning water remaining on the substrate during the processing method from the previous stage. With this additive, a corrosion-resistant thin film having no streaks and good color can be obtained. Cellulose compounds are known as water-soluble thickeners, and about 0.0 to 10 grams, preferably 0.0 to 20 grams, more preferably 0.5 to 1.5 grams per liter of aqueous solution. A range, for example an amount of 1.0 grams, may be present in the acidic aqueous solution. Depending on the characteristics of the anodized aluminum, an effective amount of at least one water-soluble surfactant or humectant is about 0.0-10 grams, preferably 0.0-2.0 grams per liter of acidic aqueous solution. Suitably an amount in the range of 0.5 to 1.5 grams, for example 1.0 grams, may be added to the acidic aqueous solution. These water-soluble surfactants or humectants are known and are selected from the group consisting of nonionic, cationic and anionic surfactants.

Trivalent chromium is added as a water-soluble trivalent chromium compound, preferably as a trivalent chromium salt. Specifically, when preparing the acidic aqueous solution of the present invention, it is advantageous to add a chromium salt to the solution so that it becomes chromium in an aqueous state having a valence of +3. For example, suitable chromium compounds include Cr ₂ (SO ₄ ) ₃ , (NH ₄ ) Cr (SO ₄ ) ₂ , KCr ₂ (SO ₄ ) ₂ and any mixtures or combinations of these compounds in solution. Can be prepared. The aluminum substrate is either phosphoric acid anodized aluminum or an anodized aluminum alloy containing 60% or more by weight of aluminum. Suitable trivalent chromium concentrations range from about 4.0 to 8.0 grams or 6.0 grams per liter of aqueous solution. It has been found that particularly good results are obtained when the trivalent chromium compound is present in these preferred ranges. The preferred amount of addition of metal fluoride zirconate to the acidic solution is in the range of about 6.0 to 10 grams or 8.0 grams per liter of solution.

  The treatment or sealing of the phosphoric acid anodized aluminum can be performed at a low temperature around room temperature or a temperature of about 93.3 ° C. or lower. Treatment at room temperature is desirable in that a heating tool is not required. The sealing coating may be performed by air drying known to those skilled in the art, for example, oven drying, forced air drying, exposure to an infrared lamp, or the like. For the purposes of the present invention, the terms phosphoric acid anodized aluminum and anodized aluminum alloy include aluminum and its alloys phosphoric acid anodized by methods known to those skilled in the art.

  In some treatments, alkali metal tetrafluoroborate and / or hexafluorosilicate is added to the acidic solution in a low concentration of 0.001 grams per liter within the upper limit of solubility of the compound. Is done. For example, about 50% by weight of fluorinated silicate is added based on the weight of fluorinated zirconate. In other words, 8.0 grams of fluorinated zirconate per liter and about 4.0 grams of fluorinated silicate per liter are added to the solution. For example, as a variant, about 0.01 to 100% by weight of fluorinated borate is added based on the weight of the fluorinated zirconate. Preferably, about 1 to 10% by weight, for example about 3% by weight, of fluorinated borate is added based on the weight of the fluorinated zirconate salt. Specific examples include about 8.0 grams of potassium fluoborate per liter, about 6.0 grams of basic chromium (III) sulfate per liter, and about 0.1 to 5.0 grams per liter. Of divalent zinc sulfate and about 0.12 to 1.2 grams of potassium tetrafluoroborate and / or hexafluorosilicate in one liter. The addition of stabilizers such as fluorinated borate and / or hexafluorosilicate has the important result that the pH is maintained between about 2.5 and 5.5 and the solution is stabilized. However, in order to maintain the pH in the range of about 2.5 to 5.5 or less, for example, about 3.25 to 3.5, an effective amount of diluted acid or base is added to the pretreatment liquid to finely adjust the pH. It may be necessary to do this.

  The composition or the acidic solution may contain a zinc compound in order to further improve the corrosion resistance of the phosphoric acid anodized film as compared with a composition not containing a divalent zinc compound. The components in the solution are mixed in water and can be used without further chemical manipulation. Any divalent zinc can be supplied as long as it is dissolved in water at the required concentration within the range of 0.001 to 10 grams and can coexist with other compounds in solution. Particularly suitable components include, for example, zinc acetate, zinc telluride, zinc tetrafluoroborate, zinc molybdate, zinc hexafluorosilicate, zinc sulfate, and the like, and combinations at any ratio thereof.

  The following examples demonstrate the use of the stable sealing coating solution of the present invention and the solution to maintain adhesion properties while improving the corrosion resistance of the phosphoric acid anodized aluminum and its alloys.

<Example 1> TCP5PZ2
Anodized aluminum phosphate and aluminum containing about 3.0 grams of basic chromium (III) sulfate, about 4.0 grams of potassium hexafluorozirconate and about 1.0 grams of zinc sulfate per liter of solution A stable acidic aqueous solution having a pH in the range of about 3.45 to 4.0 used for the post-treatment of the alloy to form a corrosion-resistant colored coating.

<Example 2> TCP5B3
Phosphoric acid comprising about 3.0 grams of basic chromium (III) sulfate, about 4.0 grams of hexafluorozirconate potassium salt and about 0.12 grams of zinc tetrafluoroborate per liter of solution A stable acidic aqueous solution used for post-treatment of anodized aluminum and aluminum alloys to form a corrosion-resistant coating.

<Example 3> TCP5B3Z4
About 3.0 grams of basic chromium (III) sulfate per liter of solution, about 4.0 grams of potassium hexafluorozirconate, about 0.12 grams of zinc tetrafluoroborate and about 2.0 A stable acidic aqueous solution containing gram zinc sulfate for post-treatment of aluminum phosphate anodized aluminum and aluminum alloys to form a corrosion resistant colored coating.

  Table 1 shows the corrosion evaluation of the three examples of the present invention used for the post-treatment of the phosphoric acid anodized aluminum alloy in comparison with the coating composition of Example 2. Example 3 (TCP5B3Z4) and Example 1 (TCP5PZ2) showed higher ratings on average.

Table 1 Corrosion resistance of sealant-treated 2024-T3 aluminum alloy phosphoric acid anodic oxide after 1000 hours exposure by ASTM B117 salt spray.

<Example 4>
3.0 grams of basic chromium (III) sulfate per liter and 4.0 grams of potassium hexafluorozirconate per liter were added to deionized water. Diluted potassium hydroxide or dilute sulfuric acid was used and maintained at pH 3.25-3.60 for 14 days. After 14 days, the pH was adjusted to 3.90 ± 0.05 and allowed to stand overnight. The solution was put to use.

<Example 5>
3.0 grams of basic chromium (III) sulfate in 1 liter, 4.0 grams of hexafluorozirconate potassium salt, and 0.12 grams of potassium tetrafluoroborate were added to deionized water. . The solution was held for about 10 days or until the pH rose between 3.75 and 4.00. The solution was put to use.

<Example 6>
In Example 4, 1.0 gram of zinc sulfate per liter was added during the initial mixing. The solution was put to use.

<Example 7>
In Example 4, 2.0 grams of zinc sulfate per liter was added during the initial mixing. The solution was put to use.

<Example 8>
As described below, post-treatment of aluminum phosphate anodized was performed to form a film. Throughout, the phosphoric acid anodizing method according to ASTM D3933 “Standard procedure for aluminum surface treatment for structural adhesive bonding (phosphoric acid anodizing)” was followed. Immediately after anodizing the aluminum alloy panel of 7.6 cm × 25.4 cm × 0.8 cm (3 inch × 10 inch × 0.32 inch) by the phosphoric acid anodizing method, the panel was washed twice with deionized water. Washed. Immediately after washing with water, the panel was immersed in the solution of either Example 6 or Example 7 at room temperature for 10 minutes. Immediately after soaking, it was washed twice with deionized water. The panel was air-dried at room temperature and then subjected to a neutral salt spray method according to ASTM B 117. The test panel was held on a shelf at 15 ° C. during the test load. A non-sealed phosphoric acid anodic oxidation (PAA) panel was used as a reference to be placed on the test coating and tested.

  FIG. 2 and FIG. 3 (photographs) show the characteristics of the compositions of Example 5 and Example 6. FIG. 1 (photo) shows an unsealed PAA panel after exposure by the ASTM B 117 neutral salt spray method. The post-treatment of FIGS. 2 and 3 improved the corrosion resistance compared to the case where the post-treatment of FIG. 1 was not performed.

<Example 9>
The specimen was anodized in the same manner as in Example 8. In this example, the compositions (solutions) of Example 5 and Example 7 were heated to 37.8 ° C. (100 ° F.), and the panel was immersed for a total of 10 minutes. 4 and 5 (photographs) show the corrosion characteristics after 1000 hours exposure to the ASTM B 117 neutral salt spray method. In the composition of Example 7, the corrosion resistance was clearly improved as compared with the composition of Example 5.

<Example 10>
The specimen was anodized in the same manner as in Example 8. In this example, the compositions (solutions) of Example 5 and Example 7 were maintained at room temperature of 23.8 ° C. (75 ° F.), and the panel was immersed for a total of 40 minutes. FIG. 6 and FIG. 7 (photographs) show the corrosion resistance after 1000 hours exposure by ASTM B 117 neutral salt spray method.

<Example 11>
The specimen was anodized in the same manner as in Example 8. In this example, the compositions (solutions) of Example 5 and Example 6 were heated to 65.6 ° C. (150 ° F.), and the panel was immersed for a total of 5 minutes. FIG. 6 and FIG. 7 (photographs) show the corrosion resistance after 1000 hours exposure by ASTM B 117 neutral salt spray method. Table 2 shows a comparison of the results of the corrosion resistance performance of each example based on numerical evaluation according to ASTM D 1654. The best score on the ASTM evaluation method is 10, which means that there is almost no corrosion on the test panel. When the evaluation drops to 1, it indicates that almost 100% of the panel surface has been corroded. From the data in Table 2, the treatment method of the present invention is clearly improved as compared with the conventional method in the post-treatment or sealing of phosphoric acid anodized aluminum and its alloys.

Table 2 Corrosion numerical evaluation of the composition (solution) and the panel treated by the treatment method of the present invention is based on ASTM D 1654, with an evaluation value from a maximum of 10 (no corrosion) to a minimum of 1 (complete corrosion) without post-treatment. Cross over. The evaluation value includes the average value of three evaluation panels under each condition.

  For the purposes of the present invention, a water-soluble surfactant or humectant may be added to the trivalent chromium solution in the range of about 0-10 grams per liter, preferably about 0.5-1.5 grams. it can. When the surfactant is added to the aqueous solution, the surface tension that prevents the treatment composition from spreading is reduced, wettability is improved, and the coating on the coated surface becomes uniform. Surfactants include at least one water-soluble composition selected from the group consisting of nonionic, anionic and cationic surfactants. Known water-soluble surfactants that can be dissolved at the required concentrations include monocarboximidoazoline, alkyl sulfate sodium salt (DUPONOL®), tridecyloxypoly (alkylenoxyethanol) ethoxylated or propoxylated alkylphenols. (IGEPAL (registered trademark)), alkylsulfonamide, alkaryl sulfate, palmitic alkanolamide (CENTROL (registered trademark)), octylphenyl polyethoxyethanol (TRITON (registered trademark)), sorbitan monopalmitate (SPAN (registered trademark)) )), Dodecylphenyl polyethylene glycol ether (eg, TERGITOL®), alkylpyrrolidone, polyalkoxylated fatty acid ester, alkylbenzenesulfonic acid and Mixtures of al and the like. Other known water-soluble surfactants include alkylphenol alkyl oxylates, preferably nonylphenol effyl oxylates, which have an ethylene oxide adduct with at least one sulfonic acid substituent and an aliphatic amine on the phenyl ring. The anionic surfactant of these is mentioned. Other known water-soluble surfactants are shown in "Surfactants and Surfactant Action Systems" (3rd edition Kirk Osmer Chemical Dictionary, published by John Wiley & Sons).

  When the surface cannot be immersed due to a large surface area or when spraying on a vertical surface, a thickener is added to maintain the contact condition with the aqueous solution on the surface. As the thickener to be used, water-soluble inorganic and organic thickeners are known. For example, an effective amount with respect to a trivalent chromium solution (0 to 10 grams per liter of acidic solution, preferably 0.5 to 1. In the range of 5 grams). Specific examples of suitable thickening agents include cellulose compounds such as hydroxypropyl cellulose (crucelle, etc.), ethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, methyl cellulose, and mixtures thereof. Suitable thickeners then include water soluble inorganic thickeners such as colloidal silica, bentonite and other clays, starch, gum arabic, gum tragacanth, agar and various combinations.

  After the surface treatment by a normal phosphoric acid anodizing method, the solution can be applied by dipping, spraying or coating. The solution can be heated up to 65 ° C., and it is optimal to further improve the corrosion resistance of the phosphoric acid anodized non-film by dipping. Depending on the liquid temperature and the solution concentration, the solution residence time can be adjusted in about 1 to 60 minutes. After residence, the remaining solution is tapped off the substrate or washed thoroughly with deionized water. No additional chemical manipulation of the laminated film is necessary to achieve good performance. However, the use of a strong oxidizing solution can improve the corrosion resistance of the thin film. It is presumed that the corrosion resistance is further improved because hexavalent chromium is generated from trivalent chromium in the thin film. The water-soluble sealing composition may be sprayed from a spray tank designed as an alternative to a dip tank. This reduces the actual amount of compound from about 3780 liters (1000 gallons) to about 114-189 liters (30-50 gallons).

  Another feature of the present invention is that this protective sealing coating allows the corrosion resistance of phosphoric acid anodized aluminum to be comparable to that of anodic oxides with sulfuric acid, chromic acid, boric acid-sulfuric acid or other known compositions. Or more. This possibility does not exist so far and provides a new potential application where it can be applied in corrosive environments where phosphoric acid anodization could not previously be used. Phosphoric anodized aluminum is very advantageous in that the coating weight is typically 1/10 to 1/50 that of other coatings. This results in significant structural aluminum alloy weight reduction and reduced metal fatigue. In addition, the present invention creates the possibility of improving the properties of the phosphoric acid anodizing coating currently introduced as an adhesive bond substitute for chromic acid anodizing. Conventionally, it has been said that phosphoric acid anodized coatings that have not been post-treated have poor corrosion resistance but excellent adhesive properties. However, the present invention improves the corrosion resistance of anodized aluminum while maintaining the adhesive bond strength of the coating. The terms “solubility” and “water solubility” in the present invention mean water solubility sufficient to contain the compound used in the solution of the present invention at least at the concentrations described herein.

  While the invention has been described in terms of many specific embodiments, it will be apparent that other variations and modifications may be made without departing from the scope of the invention as defined in the following claims.

It is the photograph of the phosphoric acid anodized aluminum 2024-T3 without the post-processing exposed by the ASTM-B117 salt spray test for 24 hours (1 day). Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 5 (soaked at about 23.9 ° C. for 10 minutes) after 96 hours (4 days) exposure by the ASTM-B117 salt spray test It is. Photograph of aluminum phosphate anodized aluminum 2024-T3 post-treated with the composition of Example 6 (soaked at about 23.9 ° C. for 10 minutes) after being exposed to ASTM-B117 salt spray test for 96 hours (4 days) It is. Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 5 (soaked at about 37.8 ° C. for 10 minutes) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is. Photograph of aluminum phosphate anodized aluminum 2024-T3 post-treated with the composition of Example 7 (soaked at about 37.8 ° C. for 10 minutes) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is. Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 5 (soaked at about 23.9 ° C. for 40 minutes) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is. Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 7 (approx. 23.9 ° C., 40 minutes immersion) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is. Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 5 (immersion at about 65.6 ° C. for 5 minutes) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is. Photograph of anodized aluminum phosphate 2024-T3 post-treated with the composition of Example 6 (soaked at about 65.6 ° C. for 5 minutes) after 1000 hours (42 days) exposure by ASTM-B117 salt spray test It is.

Claims (15)

A method for sealing pores of phosphoric acid anodized aluminum and phosphoric acid anodized aluminum alloy,
0 Ri per l of solution. 01-22 grams of trivalent chromium compound,
0 . At least one fluorine compound selected from the group of alkali metal tetrafluoroborate, alkali metal hexafluorosilicate and mixtures thereof in the range of 0-12 grams;
Alkali metal hexafluoride zirconate in the range of 0.01-12 grams;
0 . At least one divalent zinc compound in the range of 001-10 grams;
0.0 to 1 0, at least one water-soluble thickening agent in the range of grams, and 0.0 to 1 0 contains at least one water-soluble surfactant of gram-free 2. A treatment method of treating phosphoric acid anodized aluminum and aluminum phosphate anodized alloy with an acidic aqueous solution having a pH of 5 to 5.5 to improve corrosion resistance and maintain adhesive bond strength.   The processing method according to claim 1, wherein the divalent zinc compound is in the range of 0.1 to 2.0 grams per liter of the solution. PH of the acidic aqueous solution is 3 . The processing method according to claim 1, which is in the range of 7 to 4.0, and the temperature of the acidic aqueous solution is in the range of from about room temperature to 93.3 ° C. The trivalent chromium compound is 4 . A water-soluble compound in the range of 0 to 8.0 grams, wherein the alkali metal hexafluorozirconate is 6 . 0-10 g water-soluble compounds ranging, the fluorine compound is 0. The processing method of claim 1, which is a water-soluble compound in the range of 12 to 1.2 grams. The water-soluble thickener is 0 . In the range of 5 to 1.5 grams and the water-soluble surfactant is 0 . The processing method of claim 1, which is in the range of 5 to 1.5 grams. The fluorine compound is dissolved in the acidic aqueous solution by 0.1 . 24 to 0.36 Gram exist, the phosphoric acid anodized Kaa aluminum or the phosphate anodized aluminum alloy is washed with subsequently 93.3 ° C. below the temperature, processing method according to claim 1. 0 Ri per the water-soluble thickening agent is the acidic aqueous solution liter. The processing method of claim 1, wherein the cellulose compound is present in an amount ranging from 5 to 1.5 grams.   The processing method according to claim 1, wherein the trivalent chromium salt is chromium sulfate.   The processing method according to claim 1, wherein the alkali metal hexafluoride zirconate is potassium hexafluorozirconate. The trivalent chromium salt is 4 . Chromium sulfate in the range of 0 to 8.0 grams, wherein the alkali metal hexafluoride zirconate is 6 . 0 to 10 grams of potassium hexafluorozirconate, wherein the alkali metal tetrafluoroborate is 0 . The processing method of claim 1, which is in the range of 24-0.36 grams.   The processing method according to claim 1, wherein the divalent zinc compound is at least one of zinc acetate and zinc sulfate.   The processing method according to claim 1, wherein the water-soluble surfactant is selected from the group consisting of water-soluble nonionic, anionic and cationic. The zinc sulfate is 0 . 12. A process according to claim 11 present in the aqueous solution in an amount ranging from 1 to 5.0 grams. The trivalent chromium compound is 4 . Present in an aqueous solution in an amount ranging from 0 to 8.0 grams, wherein the mixture of alkali metal tetrafluoroborate and alkali metal hexafluorosilicate is . The processing method of claim 1, wherein the treatment method is present in the aqueous solution in an amount ranging from 001 to 12 grams. An anodized aluminum phosphate and an anodized aluminum phosphate alloy coated by the sealing treatment method according to claim 1.

Images