JP5563236B2 - Chromium-free chemical conversion treatment solution, chemical conversion treatment method, and chemical conversion treatment article - Google Patents

Description

  The present invention relates to a chromium-free chemical conversion treatment liquid, a chemical conversion treatment method, and a chemical conversion treatment article. More specifically, imparting good corrosion resistance and paint adhesion to metal materials typified by aluminum die-cast materials used in a wide range of fields such as automotive parts and electrical equipment resin base materials without using chromium. The present invention relates to a chemical conversion treatment liquid capable of forming a chemical conversion, a chemical conversion treatment method using the chemical conversion treatment liquid, and a chemical conversion treatment article treated by the treatment method.

  As a rust-proofing method for metal materials such as aluminum and aluminum alloy materials typified by aluminum die-cast materials (hereinafter also simply referred to as “metal materials”), chromic acid, dichromic acid or chromate is used. A treatment with a treating agent containing (referred to as chromate treatment) has been used for many years. This chromate treatment is performed for the purpose of improving the rust prevention property and the adhesion of the top coat to the metal material. In particular, the chemical conversion-type chromate treatment has been widely performed because it has high productivity that it can be uniformly treated without being restricted by the shape of the workpiece, and the formed chromate film also has good corrosion resistance.

  However, as is well known, development of alternative technologies has been studied due to the problem of environmental pollution, and various proposals have been made. For example, Patent Document 1 below proposes a base chemical conversion treatment agent composed of a water-soluble zirconium compound and / or a water-soluble titanium compound and an organic phosphonic acid. Patent Document 2 listed below includes at least one selected from the group consisting of Ti, Zr, Hf and Si, naphthalenesulfonic acid, naphthalenesulfonic acid-formaldehyde condensate, styrenesulfonic acid, polystyrenesulfonic acid, vinylamine, polyvinyl A chemical conversion treatment agent, a chemical conversion treatment method and a chemical conversion treated metal material containing a specific amount of at least one selected from the group consisting of amine, allylamine and polyallylamine have been proposed. Further, Patent Document 3 below proposes a surface treatment composition for an aluminum-containing metal material containing a specific phenol resin and a surface treatment method with respect to titanium or a zirconium compound.

JP 2003-313679 A JP 2005-264230 A JP-A-9-31404

"NIPPON STEEL MONTHLY" June 2005 issue (published by Nippon Steel Corporation, pages 9-10)

  The techniques of the above Patent Documents 1 to 3 propose a chemical conversion treatment liquid and a chemical conversion treatment method having a specific composition not containing chromium, and that the corrosion resistance and paint adhesion of the applied metal material are good. is there. However, its corrosion resistance and paint adhesion are not always perfect, especially when applied to metal materials such as aluminum and aluminum alloy materials typified by aluminum die-cast materials, etc. However, it is difficult to obtain sufficient corrosion resistance.

  The present invention has been made in order to solve the above-mentioned problems of the prior art, and the object thereof is the surface of a metal material, particularly a metal such as aluminum and aluminum alloy material represented by an aluminum die-cast material. An object of the present invention is to provide a chromium-free chemical conversion treatment solution that can replace a reactive chromate treatment solution using a chromium compound when applied to the surface of a material, and can impart good corrosion resistance and paint adhesion. Another object of the present invention is to provide a chemical conversion treatment method using such a chromium-free chemical conversion treatment solution and a chemical conversion treatment article treated by the chemical conversion treatment method.

  In order to solve the above-mentioned problems, the present inventor has studied means for imparting good corrosion resistance to a metal material regardless of the presence or absence of an overcoating on the surface of the metal material. The characteristics of the chromate-treated film are, for example, as described in Non-Patent Document 1 above, a barrier effect of a network structure mainly composed of trivalent chromium and oxygen, and a self-repair function by a small amount of hexavalent chromium contained therein. It is in. The inventor determined the function of trivalent chromium in a titanium compound and the function of hexavalent chromium in a vanadium compound, and intensively studied the composition and processing method of a chromium-free chemical conversion treatment liquid containing both. As a result, an aqueous treatment liquid containing a specific amount of titanium complex fluoride ions and pentavalent vanadium compound ions and adjusted to a pH in the range of 2.4 to 4.4 is brought into contact with the surface of the metal material, and then washed with water. It was found that when a chemical conversion film containing Ti and V in a specific amount and a specific ratio was formed on the surface of the metal, the chemical conversion film showed good corrosion resistance and paint adhesion. Furthermore, the present inventor has also found that the corrosion resistance may be further improved by further containing a specific amount of zirconium complex fluoride ions in the chemical conversion solution. The present invention has been completed based on these findings.

  That is, the chromium-free chemical conversion treatment solution according to the present invention for solving the above problems comprises a titanium complex fluoride ion having a Ti equivalent concentration of 2 to 400 ppm and a pentavalent vanadium compound ion having a V equivalent concentration of 10 to 1000 ppm. It contains, pH is in the range of 2.4-4.4.

  In a preferred embodiment of the chromium-free chemical conversion treatment liquid according to the present invention, the Ti equivalent concentration A of the titanium complex fluoride ion and the V equivalent concentration B of the pentavalent vanadium compound ion are 0 by weight ratio (A / B). .. configured to be within the range of 1 to 4.5.

  A preferred embodiment of the chromium-free chemical conversion treatment liquid according to the present invention is configured to further contain a zirconium complex fluoride ion having a Zr equivalent concentration of 1-1000 ppm.

  The preferable aspect of the chromium-free chemical conversion treatment liquid according to the present invention is configured to be used for aluminum or an aluminum-containing metal material.

The chemical conversion treatment method according to the present invention for solving the above-described problems contains a titanium complex fluoride ion having a Ti equivalent concentration of 2 to 400 ppm and a pentavalent vanadium compound ion having a V equivalent concentration of 10 to 1000 ppm, and a pH. Is in the range of 2.4 to 4.4 and the liquid temperature is in the range of 35 to 75 ° C., the chrome-free chemical conversion treatment liquid is brought into contact with the surface of the metal material, washed with water, and the surface of the metal material Further, the chemical conversion treatment in which the Ti amount C and the vanadium amount D are in the range of 0.2 to 8.0 in terms of weight ratio (C / D) and in the range of 20 to 350 mg / m ² in terms of the total weight (C + D). A film is formed.

In a preferred embodiment of the chemical conversion treatment method according to the present invention, the chemical conversion treatment solution further contains a zirconium complex fluoride ion having a Zr equivalent concentration of 1 to 1000 ppm, and the chemical conversion treatment film contains Ti amount C, V amount D, and The Zr amount E is configured such that the weight ratio {(C + E) / D} is in the range of 0.2 to 8.0 and the total weight (C + D + E) is in the range of ²⁰ to 350 mg / m ² .

  The preferable aspect of the chemical conversion treatment method according to the present invention is configured such that the metal material is aluminum or an aluminum-containing metal material.

  The chemical conversion treatment article according to the present invention for solving the above-mentioned problems is characterized by being processed by the chemical conversion treatment method according to the present invention.

  According to the chromium-free chemical conversion treatment liquid and chemical conversion treatment method of the present invention, when applied to metal materials, particularly metal materials such as aluminum and aluminum alloy materials represented by aluminum die-cast materials, harmful chromium compounds are added. Without use, a chemical conversion treatment film that imparts good corrosion resistance and paint adhesion can be formed on the surface of the metal material. In particular, sufficient corrosion resistance can be obtained by “bare specification” without painting. Moreover, since it is a reaction type chemical conversion treatment solution, it is possible to form a uniform chemical conversion treatment film without being restricted by the shape of the object to be processed, and thus high productivity can be secured. Further, since it does not contain not only chromium compounds but also phosphoric acid that leads to eutrophication of rivers and lakes, the industrial utility value is great, and it can replace a reactive chromate treatment solution using chromium compounds.

  According to the chemical conversion treatment article according to the present invention, particularly when a metal material such as aluminum and aluminum alloy material typified by an aluminum die cast material is used as an article to be treated, it has good corrosion resistance and paint adhesion, In particular, it has sufficient corrosion resistance in the “bare specification” without painting.

  Hereinafter, the chromium-free chemical conversion treatment liquid, chemical conversion treatment method, and chemical conversion treatment article according to the present invention will be described in more detail with reference to embodiments. “Ppm” is mg / liter, and “converted concentration” is the mass concentration (ppm) in terms of atomic weight.

[Chromium-free chemical treatment solution]
The chromium-free chemical conversion treatment liquid according to the present invention contains a titanium complex fluoride ion having a Ti equivalent concentration of 2 to 400 ppm and a pentavalent vanadium compound ion having a V equivalent concentration of 10 to 1000 ppm, and a pH of 2.4 to It is configured to be within the range of 4.4.

  As the metal material to be treated by this chemical conversion treatment liquid, aluminum and aluminum alloy materials represented by aluminum die-cast materials can be preferably mentioned, and good corrosion resistance and paint adhesion can be given. It is applicable to. Although such a metal material is not particularly limited, an example is a metal material containing an aluminum component.

Titanium complex fluoride ions are contained in the chemical conversion solution at a concentration in terms of Ti of 2 to 400 ppm. This complex fluoride ion is included for the purpose of forming a barrier film that is considered to be mainly composed of titanium oxide (TiO ₂ ) on the surface of the metal material. When the content of titanium complex fluoride ions is less than 2 ppm in terms of Ti, the rust preventive effect of the chemical conversion coating formed on the surface of the metal material is not sufficient. Moreover, even if the content exceeds 400 ppm in terms of Ti, no further improvement in rust prevention effect can be expected, which is economically disadvantageous. A more preferable range of the content is 10 to 200 ppm in terms of Ti.

The compound that dissolves in the chemical conversion treatment liquid in order to contain the titanium complex fluoride ion in the chemical conversion treatment liquid is not particularly limited. For example, titanium hydrofluoric acid, or an alkali metal salt or ammonium salt thereof is preferable. Used for. Specific examples include H ₂ TiF ₆ , (NH ₄ ) ₂ TiF ₆ , K ₂ TiF ₆ , Na ₂ TiF _{6, and the} like. These may be used alone or in combination of two or more.

The pentavalent vanadium compound ion is contained in the chemical conversion solution at 10 to 1000 ppm in terms of V. This compound ion is taken into the barrier film that is thought to be mainly composed of titanium oxide (TiO ₂ ) formed by contact of the chemical conversion solution with the surface of the metal material, for the purpose of exerting a self-repair function in the future. include. When the content of the pentavalent vanadium compound ion is less than 10 ppm in terms of V, the rust preventive effect of the chemical conversion coating formed on the surface of the metal material is not sufficient. Moreover, even if the content exceeds 1000 ppm in V conversion density | concentration, it will not be taken in into a barrier film any more and is meaningless. From the viewpoint of the self-repairing function carried by V, it is desirable to contain a relatively large amount of V, and a more preferable range of the content is 45 to 1000 ppm in terms of V.

The compound dissolved in the chemical conversion treatment liquid for containing the pentavalent vanadium compound ion in the chemical conversion treatment liquid is not particularly limited as long as it is water-soluble and generates vanadium oxoacid ions. For example, vanadic acid Potassium (K ₃ VO ₄ ), sodium vanadate (Na ₃ VO ₄ ), ammonium vanadate ((NH ₄ ) ₃ VO ₄ ), potassium metavanadate (KVO ₃ ), sodium metavanadate (NaVO ₃ ), ammonium metavanadate it can be mentioned (NH 4 _{VO 3)} 5-valent vanadium compounds such as, but can be others. These may be used alone or in combination of two or more.

  The pH of the chemical conversion solution is adjusted within the range of 2.4 to 4.4. By setting the pH within this range, a chemical conversion treatment film with stable corrosion resistance can be formed, and a chemical conversion treatment solution with good stability can be obtained. When the pH is less than 2.4, when the chemical conversion treatment solution comes into contact with the surface of the metal material, the etching action on the surface becomes strong, and particularly around the segregation component such as Si in the aluminum die cast. Etching occurs, and the chemical conversion film becomes non-uniform, resulting in poor corrosion resistance. Moreover, when pH exceeds 4.4, stability of a chemical conversion liquid will become inadequate and practical inconveniences, such as white turbidity and precipitation, will arise. A more preferable pH range is 2.6 to 4.2, and a particularly preferable pH range is 3.1 to 4.1.

  For pH adjustment, for example, an inorganic acid such as hydrofluoric acid, sulfuric acid, nitric acid, hydrochloric acid or the like, or after or without adding ammonia, sodium carbonate, sodium hydroxide, potassium hydroxide, etc. The basic substance is added.

  The chemical conversion treatment liquid according to the present invention does not contain a chromium compound and phosphoric acid. Chromium compounds are not included because environmental issues are taken into consideration.Phosphoric acid is not included because phosphoric acid-containing wastewater after detoxification treatment may be released into rivers and lakes, resulting in eutrophication. Furthermore, it is because the wastewater treatment cost in the case of containing a chromium compound or phosphoric acid increases.

  When the chemical conversion treatment liquid of the binary system (Ti and V) according to the present invention constructed in this way is applied to the surface of a metal material such as aluminum and aluminum alloy material typified by aluminum die-cast material, etc., titanium It is possible to form a chemical conversion film having good corrosion resistance and paint adhesion, including vanadium and vanadium. This chemical conversion treatment liquid can replace the reactive chromate treatment liquid using a chromium compound.

  Next, the composition contained in the chemical conversion treatment liquid will be described. When the Ti equivalent concentration of titanium complex fluoride ion is A and the V equivalent concentration of pentavalent vanadium compound ion is B, the titanium complex fluoride ion and pentavalent vanadium compound ion contained in the chemical conversion liquid are Ti equivalent concentrations. The weight ratio (A / B) of A to V equivalent concentration B is preferably in the range of 0.1 to 4.5. When the weight ratio (A / B) is less than 0.1, the ratio of titanium (Ti) in the chemical conversion film to be produced is insufficient, the barrier effect is lowered, and the expected rust prevention effect is obtained. It may not be possible. On the other hand, when the weight ratio (A / B) exceeds 4.5, the ratio of vanadium (V) in the chemical conversion film to be produced is insufficient, and the self-repair function is lowered, which is also expected prevention. Rust effect may not be obtained. From the viewpoint of the self-healing function carried by V, it is desirable to contain a relatively large amount of V. A more preferable range of the weight ratio (A / B) is 0.1 to 3.0, and a more preferable range is 0. .1 to 0.45.

It is preferable that a chemical conversion liquid contains a zirconium complex fluoride ion further. Zirconium complex fluoride ions are preferably contained in the chemical conversion solution at a Zr equivalent concentration of 1 to 1000 ppm. The chemical conversion film produced by using such a chemical conversion liquid exhibits better corrosion resistance. The reason for this is that zirconium (Zr) is mixed in the form of oxide and / or hydroxide in the barrier film that is considered to be mainly composed of titanium oxide (TiO ₂ ), and the network structure of the chemical conversion film is more precise. It is considered that the barrier effect is further enhanced. If the content of zirconium complex fluoride ions is 1 ppm or more in terms of Zr, a more preferable anticorrosive film can be obtained. However, when the content exceeds 1000 ppm in terms of Zr, no further rust prevention effect can be expected. In addition, it is preferable that the upper limit of content is 500 ppm in Zr conversion density | concentration. In many cases, even if the content exceeds 500 ppm in terms of Zr conversion, no further rust prevention effect can be expected and it is useless.

The compound that dissolves in the chemical conversion treatment liquid in order to contain the zirconium complex fluoride ion in the chemical conversion treatment liquid does not impair the stability of the chemical conversion treatment liquid, and makes the network structure of the obtained chemical conversion treatment film more precise. Although it will not specifically limit if it is a compound which raises a barrier effect more, For example, a zirconium hydrofluoric acid or its alkali metal salt, ammonium salt, etc. are used suitably. Specific examples include H ₂ ZrF ₆ , (NH ₄ ) ₂ ZrF ₆ , K ₂ ZrF ₆ , Na ₂ ZrF _{6, and the} like. These may be used alone or in combination of two or more.

  The thus formed ternary system (Ti, V and Zr) chemical conversion treatment liquid according to the present invention is applied particularly to the surface of metal materials such as aluminum and aluminum alloy materials typified by aluminum die-cast materials. Further, a chemical conversion treatment film having good corrosion resistance and paint adhesion containing titanium, vanadium and zirconium can be formed. In particular, zirconium makes the chemical conversion coating denser and improves the corrosion resistance.

[Chemical conversion treatment method]
In the chemical conversion treatment method according to the present invention, the chromium-free chemical conversion treatment liquid according to the present invention is washed with water after contacting the surface of the metal material, and a chemical conversion film having a specific composition is formed on the surface of the metal material. Is the method. The chemical conversion treatment liquid to be used is the chemical conversion treatment liquid according to the present invention described above, and may be a binary chemical conversion treatment liquid for producing a chemical conversion treatment film containing titanium and vanadium, or titanium, vanadium and zirconium. It may be a ternary chemical conversion treatment liquid for producing a chemical conversion treatment film containing. The kind and concentration of titanium complex fluoride ion, pentavalent vanadium compound ion, zirconium complex fluoride ion, pH, etc. are as described above.

  The liquid temperature of the chemical conversion treatment liquid needs to be in the range of 35 to 75 ° C. When the liquid temperature is less than 35 ° C., the etching action on the surface when the chemical conversion treatment liquid contacts the surface of the metal material is weak, and the action of forming a barrier film on the surface is not sufficient. On the other hand, even if the liquid temperature exceeds 75 ° C., not only a film forming effect can be obtained, but the heat cost required for heating is increased, water evaporation becomes significant, white turbidity, precipitation, etc. occur. Problems can arise. More preferably, it exists in the range of 45-70 degreeC, More preferably, it exists in the range of 50-65 degreeC.

  The contact time of the chemical conversion solution to the surface of the metal material should be between 1 and 600 seconds. If the contact time is less than 1 second, the formation of a barrier film on the surface is not sufficient. On the other hand, even if the contact time exceeds 600 seconds, no further film formation is performed, which is wasteful from the viewpoint of productivity, and the processing solution may become cloudy or precipitate. From the viewpoint of obtaining more stable corrosion resistance, the time is more preferably 5 to 280 seconds, and further preferably 15 to 180 seconds. There is no restriction | limiting in particular about a contact means, The spray method, the immersion method, etc. are used suitably.

  In addition, the metal material which contacted the chemical conversion liquid and formed the chemical conversion film on the surface enters a cleaning process and is cleaned. As the cleaning liquid, water is usually used, but it may be a water-soluble solvent or a surfactant aqueous solution. Moreover, there is no restriction | limiting in particular also about a washing | cleaning means, The spray method, the immersion method, etc. are used suitably. By such cleaning, unreacted processing liquid components adhering to the surface are removed.

[Chemical conversion treatment article]
The chemical conversion treatment article according to the present invention is processed by the chemical conversion treatment method according to the present invention, and has a chemical conversion treatment film having a specific composition on the surface thereof. In particular, when a metal material such as aluminum and an aluminum alloy material typified by an aluminum die-cast material is used as the article to be treated, the chemical conversion article according to the present invention has good corrosion resistance and paint adhesion. In particular, it has sufficient corrosion resistance even in the bare specification without painting. Needless to say, it may be a paint specification.

When the chemical conversion treatment liquid is a binary system of Ti and V, the generated chemical conversion coating usually contains 1 to 200 mg / m ² of Ti and 1 to 200 mg / m ² of V in terms of weight, and When the Ti amount is C and the V amount is D, the weight ratio C / D is in the range of 0.2 to 8.0, and the total weight C + D is in the range of ²⁰ to 350 mg / m ² .

  The weight ratio C / D indicates the ratio of Ti that bears the barrier effect to V that bears the self-repair function. If the value is less than 0.2, the ratio of titanium (Ti) in the formed chemical conversion coating is insufficient, the network structure becomes sparse, the barrier property is insufficient, and the corrosion resistance is inferior, or the chemical conversion coating Becomes fragile and causes problems such as poor paint adhesion. On the other hand, if the value exceeds 8.0, the ratio of vanadium (V) in the formed chemical conversion film is insufficient, the self-repair function is insufficient, and the corrosion resistance is inferior. More preferably, it exists in the range of 0.3-5.0, More preferably, it exists in the range of 0.4-3.0.

When the value of the total weight C + D is less than 20 mg / m ² , both the barrier property and the self-healing function are insufficient and the corrosion resistance is inferior. On the other hand, when the value exceeds 350 mg / m ² , the surface of the metal material after the chemical conversion treatment is colored and is not preferable in appearance, and when coating is performed, the adhesion may be lowered. More preferably, it is in the range of 25 to 250 mg / m ² .

When the chemical conversion treatment liquid is a ternary system of Ti, V, and Zr, the generated chemical conversion film is usually 1 to 200 mg / m ² of Ti and 1 to 200 mg in terms of weight, as in the case of the binary system. / m ² of V and 1 to 200 mg / m ² of Zr, and when Ti amount is C, V amount is D, and Zr amount is E, weight ratio (C + E) / D is 0.2 to 8 0.0 and the total weight C + D + E is in the range of ²⁰ to 350 mg / m ² . As described above, Zr is mixed in the form of oxide and / or hydroxide in the barrier film that is considered to be mainly composed of titanium oxide (TiO ₂ ), but by adding Zr to the chemical conversion film, In addition, the network structure of the film can be made denser, and the barrier effect can be enhanced as compared with the chemical conversion film not containing Zr.

  The weight ratio (C + E) / D indicates the total ratio of Ti and Zr that bears the barrier effect against V that bears the self-repair function. When the value is less than 0.2, the ratio of titanium (Ti) in the formed chemical conversion coating becomes insufficient, the network structure of the chemical conversion coating becomes sparse, the barrier property is insufficient, and the corrosion resistance is inferior. Alternatively, the chemical conversion film becomes fragile, causing problems such as poor paint adhesion. On the other hand, if the value exceeds 8.0, the ratio of vanadium (V) in the formed chemical conversion film is insufficient, the self-repair function is insufficient, and the corrosion resistance is inferior. More preferably, it exists in the range of 0.3-5.0, More preferably, it exists in the range of 0.4-3.0.

When the value of the total weight C + D + E is less than 20 mg / m ² , both the barrier property and the self-repair function are insufficient and the corrosion resistance is inferior. On the other hand, when the value exceeds 350 mg / m ² , the surface of the metal material after the chemical conversion treatment is colored and is not preferable in appearance, and when coating is performed, the adhesion may be lowered. More preferably, it is in the range of 25 to 250 mg / m ² .

  Hereinafter, although an Example and a comparative example are shown regarding the chemical conversion liquid and chemical conversion treatment method which concern on this invention, this invention is not limited by these Examples.

[Evaluation method]
A 70 mm × 150 mm aluminum die-cast panel (JIS-ADC12, manufactured by Partec Co., Ltd.) is immersed in a 2% aqueous solution of an alkaline degreasing agent (trade name: Fine Cleaner 315, Nihon Parkerizing Co., Ltd.) at 60 ° C. for 2 minutes, Then, the surface was rinsed and cleaned with running tap water (normal temperature, immersed for 30 seconds), and then subjected to chemical conversion treatment under each condition described below. After the chemical conversion treatment, it was washed again with running tap water and further washed with deionized water (room temperature, 30 seconds) and dried in an electric oven (100 ° C. × 3 minutes). 9 and Comparative Examples 1 to 6 were obtained. The obtained test piece was subjected to the following measurements and evaluations.

(Measurement of metal content)
The amount of metal in the chemical conversion coating was quantified using a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, ZSX Primus II).

(Corrosion resistance evaluation)
A salt spray test (JIS-Z2371) was performed on the test piece, and the white rust generation area after 120 hours was visually evaluated. The white rust generation area ratio is preferably 10% or less, and 5% or less is a very good level.

(Evaluation of paint adhesion)
The surface of the test piece was spray-coated with a melamine alkyd paint (trade name: Lacmin 260, manufactured by Shoko Co., Ltd.), dried at 130 ° C. for 30 minutes, and applied with a thickness of 25 μm. Thereafter, a 100 mm square cut of 2 mm square was put on the surface, immersed in boiling water for 1 hour, dried, and then peeled off. The state of the grids after peeling was observed, and 100 was evaluated as the highest and 0 as the lowest according to the number remaining after peeling the tape in 100 squares.

[Example 1]
The following chemical conversion treatment liquid 1 was prepared, and the chemical conversion treatment method 1 described below was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 1)
Titanium hydrofluoric acid (as Ti): 5 mg / liter Sodium metavanadate (as V): 45 mg / liter A / B = 0.11 (A is the concentration of titanium hydrofluoric acid, B is the concentration of sodium metavanadate is there.)
pH = 3.9 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 1)
Processing temperature: 65 ° C
Treatment time: 240 seconds Contact method: Immersion

[Example 2]
The following chemical conversion treatment liquid 2 was prepared, and the purified aluminum die cast was subjected to chemical conversion treatment by the following chemical conversion treatment method 2.

(Chemical conversion treatment liquid 2)
Titanium potassium fluoride (as Ti): 30 mg / liter Sodium vanadate (as V): 150 mg / liter A / B = 0.20 (A is the concentration of potassium titanium fluoride and B is the concentration of sodium vanadate. )
pH = 3.8 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 2)
Processing temperature: 55 ° C
Treatment time: 60 seconds Contact method: Immersion

[Example 3]
The following chemical conversion treatment liquid 3 was prepared, and the chemical conversion treatment method 3 shown below was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 3)
Titanium ammonium fluoride (as Ti): 50 mg / liter Ammonium metavanadate (as V): 200 mg / liter A / B = 0.25 (A is the concentration of titanium ammonium fluoride, and B is the concentration of ammonium metavanadate. )
pH = 3.5 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 3)
Processing temperature: 60 ° C
Treatment time: 60 seconds Contact method: Immersion

[Example 4]
The following chemical conversion treatment solution 4 was prepared, and the chemical conversion treatment method 4 shown below was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 4)
Sodium titanium fluoride (as Ti): 350 mg / liter Potassium metavanadate (as V): 900 mg / liter A / B = 0.39 (A is the concentration of sodium titanium fluoride and B is the concentration of potassium metavanadate. )
pH = 2.5 (After adding 1 g / liter of nitric acid, the pH was adjusted using a 5% aqueous potassium hydroxide solution.)
(Chemical conversion treatment method 4)
Processing temperature: 75 ° C
Processing time: 2 seconds Contact method: spray

[Example 5]
The following chemical conversion treatment liquid 5 was prepared, and the chemical conversion treatment method 5 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 5)
Titanium hydrofluoric acid (as Ti): 300 mg / liter Ammonium metavanadate (as V): 100 mg / liter A / B = 3.00 (A is the concentration of titanium hydrofluoric acid, B is the concentration of ammonium metavanadate is there.)
pH = 2.6 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 5)
Processing temperature: 40 ° C
Treatment time: 120 seconds Contact method: Immersion

[Example 6]
The following chemical conversion treatment liquid 6 was prepared, and the chemical conversion treatment method 6 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 6)
Titanium potassium fluoride (as Ti): 65 mg / liter Sodium metavanadate (as V): 15 mg / liter A / B = 4.33 (A is the concentration of potassium titanium fluoride and B is the concentration of sodium metavanadate. )
pH: 3.5 (pH was adjusted using 5% aqueous sodium hydroxide solution after adding 1 g / liter of sulfuric acid)
(Chemical conversion treatment method 6)
Processing temperature: 60 ° C
Treatment time: 280 seconds Contact method: Immersion

[Example 7]
The following chemical conversion treatment solution 7 was prepared, and the chemical conversion treatment method 7 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment solution 7)
Titanium ammonium fluoride (as Ti): 55 mg / liter Ammonium metavanadate (as V): 12 mg / liter A / B = 4.58 (A is the concentration of ammonium titanium fluoride and B is the concentration of ammonium metavanadate. )
pH = 4.0 (After adding 1 g / liter of nitric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 7)
Processing temperature: 35 ° C
Treatment time: 300 seconds Contact method: Immersion

[Example 8]
The following chemical conversion treatment liquid 8 was prepared, and chemical conversion treatment was performed on the cleaned aluminum die cast by the chemical conversion treatment method 8 below.

(Chemical conversion treatment liquid 8)
Sodium titanium fluoride (as Ti): 50 mg / liter Ammonium metavanadate (as V): 200 mg / liter Zirconium hydrofluoric acid (as Zr): 50 mg / liter A / B = 0.25 (A is the concentration of sodium titanium fluoride) And B is the concentration of ammonium metavanadate.)
pH = 4.2 (pH was adjusted with 25% aqueous ammonia after adding 1 g / liter of sulfuric acid)
(Chemical conversion treatment method 8)
Processing temperature: 60 ° C
Treatment time: 600 seconds Contact method: Immersion

[Example 9]
The following chemical conversion treatment liquid 9 was prepared, and the chemical conversion treatment method 9 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 9)
Titanium hydrofluoric acid (as Ti): 20 mg / liter Potassium vanadate (as V): 100 mg / liter Zirconium hydrofluoric acid (as Zr): 500 mg / liter A / B = 0.20 (A is titanium hydrofluoric acid And B is the concentration of potassium vanadate.)
pH = 2.7 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 9)
Processing temperature: 70 ° C
Processing time: 6 seconds Contact method: spray

[Comparative Example 1]
The following chemical conversion treatment liquid 10 was prepared, and the chemical conversion treatment method 10 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 10)
Titanium potassium fluoride (as Ti): 1 mg / liter Sodium metavanadate (as V): 50 mg / liter A / B = 0.02 (A is the concentration of potassium titanium fluoride and B is the concentration of sodium metavanadate. )
pH = 3.5 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 10)
Processing temperature: 60 ° C
Treatment time: 60 seconds Contact method: Immersion

[Comparative Example 2]
The following chemical conversion treatment liquid 11 was prepared, and the chemical conversion treatment method 11 was applied to the cleaned aluminum die cast.

(Chemical conversion treatment solution 11)
Titanium ammonium fluoride (as Ti): 50 mg / liter Ammonium metavanadate (as V): 7 mg / liter A / B = 7.14 (A is the concentration of ammonium titanium fluoride and B is the concentration of ammonium metavanadate. )
pH = 4.0 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 11)
Processing temperature: 60 ° C
Treatment time: 60 seconds Contact method: Immersion

[Comparative Example 3]
The following chemical conversion treatment liquid 12 was prepared and subjected to chemical conversion treatment by the following chemical conversion treatment method 12 on the cleaned aluminum die cast.

(Chemical conversion treatment liquid 12)
Sodium titanium fluoride (as Ti): 50 mg / liter Sodium metavanadate (as V): 200 mg / liter A / B = 0.25 (A is the concentration of sodium titanium fluoride and B is the concentration of sodium metavanadate. )
pH = 2.3 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 12)
Processing temperature: 60 ° C
Treatment time: 20 seconds Contact method: Immersion

[Comparative Example 4]
The following chemical conversion treatment liquid 13 was prepared, and the chemical conversion treatment method 13 shown below was applied to the cleaned aluminum die cast.

(Chemical conversion treatment liquid 13)
Titanium hydrofluoric acid (as Ti): 50 mg / liter Sodium vanadate (as V): 200 mg / liter A / B = 0.25 (A is the concentration of titanium hydrofluoric acid, B is the concentration of sodium vanadate is there.)
pH = 3.5 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 13)
Processing temperature: 30 ° C
Treatment time: 6 seconds Contact method: Immersion

[Comparative Example 5]
The following chemical conversion treatment solution 14 was prepared, and the chemical conversion treatment method 14 shown below was applied to the cleaned aluminum die cast.

(Chemical conversion treatment solution 14)
Titanium potassium fluoride (as Ti): 500 mg / liter Potassium metavanadate (as V): 1050 mg / liter A / B = 0.48 (A is the concentration of potassium titanium fluoride and B is the concentration of potassium metavanadate. )
pH = 3.0 (After adding 1 g / liter of sulfuric acid, the pH was adjusted with 25% aqueous ammonia.)
(Chemical conversion treatment method 14)
Processing temperature: 80 ° C
Treatment time: 240 seconds Contact method: Immersion

[Comparative Example 6]
Using a 5% aqueous solution (containing hexavalent chromium) of a chromate chemical conversion treatment agent (trademark: Alchrome 713 building bath), the cleaned aluminum die-cast was immersed at 40 ° C. for 20 seconds. Next, in the same manner as in the chemical conversion treatment method 1, washing with water, washing with deionized water, and drying were performed.

[Evaluation results]
Table 1 shows chemical conversion treatment liquids and chemical conversion treatment conditions used in Examples 1 to 9 and Comparative Examples 1 to 6, and Table 2 shows chemical conversion treatment articles obtained in Examples 1 to 9 and Comparative Examples 1 to 6. This is the evaluation result.

  As shown in Table 2, Examples 1-9 apply the chemical conversion treatment liquid according to the present invention and the chemical conversion treatment method according to the present invention, and the white rust generation area after the salt spray test is 10% or less. Performance was shown. Moreover, also regarding the paint adhesion, all the results of the cross cut test were 100, and it was confirmed that the coating was good. In addition, as shown in Table 2, these chemical conversion treatment liquids do not contain any chromium.

On the other hand, in Comparative Example 1, since the content of titanium complex fluoride ions in the chemical conversion solution is insufficient, the obtained chemical conversion film has a total weight (C + D) of Ti amount and V amount. The result was extremely low at 3.8 mg / m ^2, and both corrosion resistance and adhesion were insufficient. Moreover, since the comparative example 2 has insufficient vanadium compound ion content in a chemical conversion liquid, the obtained chemical conversion film has the weight ratio (C / D) of Ti amount and V amount as 8.5. As a result, the amount of V responsible for the self-healing function was relatively insufficient, and the total weight of Ti and V (C + D) was as low as 19 mg / m ² , resulting in insufficient corrosion resistance. In Comparative Example 3, the pH of the chemical conversion treatment solution is too low, so that the etching action on the test piece is strong, and it is considered that a non-uniform chemical conversion treatment film is formed. The weight ratio (C / D) was also significantly increased to 37.4, and V responsible for the self-healing function was relatively insufficient, resulting in poor corrosion resistance. In Comparative Example 4, since the temperature of the chemical conversion treatment liquid was too low, the formation reaction of the chemical conversion treatment film was insufficient, and as a result, the weight sum (C + D) of Ti amount and V amount was 1.7 mg / m ^2. As a result, the corrosion resistance and adhesion were insufficient. Moreover, since the compounding quantity of the titanium complex fluoride ion in a chemical conversion liquid and the vanadium compound ion was too much, the comparative example 5 has many weight total (C + D) of Ti amount and V amount as 535 mg / m < ² >. As a result, the chemical conversion film became brittle and the coating adhesion was poor. Further, Comparative Example 6 is a chromate chemical conversion treatment film, which shows the target performance of the present invention, but the present invention had properties comparable to this chromate chemical conversion treatment film.

Claims (5)

It contains a titanium complex fluoride ion having a Ti equivalent concentration of 2 to 400 ppm, a pentavalent vanadium compound ion having a V equivalent concentration of 10 to 1000 ppm, and a zirconium complex fluoride ion having a Zr equivalent concentration of 1 to 1000 ppm and a pH of 2 A chromium-free chemical conversion treatment liquid characterized by being in the range of .4 to 4.4. Used in aluminum or aluminum-containing metallic material, chromium-free chemical conversion treatment solution according to claim 1. It contains a titanium complex fluoride ion having a Ti equivalent concentration of 2 to 400 ppm, a pentavalent vanadium compound ion having a V equivalent concentration of 10 to 1000 ppm, and a zirconium complex fluoride ion having a Zr equivalent concentration of 1 to 1000 ppm and a pH of 2 The chromium-free chemical conversion treatment liquid in the range of 4.4 to 4.4 and the liquid temperature in the range of 35 to 75 ° C. is brought into contact with the surface of the metal material and then washed with water.
On the surface of the metal material, Ti amount C, V amount D and Zr amount E are within a range of 0.2 to 8.0 in weight ratio {(C + E) / D} and 20 to 20 in total weight (C + D + E). A chemical conversion treatment method comprising forming a chemical conversion treatment film in a range of 350 mg / m ² . The chemical conversion treatment method according to claim 3 , wherein the metal material is aluminum or an aluminum-containing metal material. A chemical conversion treatment article processed by the chemical conversion treatment method according to claim 3 or 4 .