KR102052659B1 - coloured trivalent chromate treating agent for galvanizing zincing, Manufacturing method thereof, and chromating method of galvanizing zincing products - Google Patents

Abstract

The present invention relates to a colored trivalent chromate treatment solution for galvanizing, a method for manufacturing the same, and a method for chromate treating a surface of a galvanized product using the same. Specifically, the galvanized product is improved in corrosion resistance and prevention of white rust. The present invention relates to a colored trivalent chromate treatment solution for zinc plating, which is capable of performing chromate treatment under mild conditions and improves the economics of galvanized products, a preparation method thereof, and a chromate treatment method for galvanized products using the same.

Description

Colored trivalent chromate treating agent for galvanizing zincing, Manufacturing method etc, and chromating method of galvanizing zincing products}

The present invention relates to a colored trivalent chromate treatment solution for galvanizing, a method for preparing the same, and a chromate treatment method for a galvanized product using the same.

As a means of preventing corrosion of a plated steel, black side, and peeling of a coating film, surface treatment has been conventionally performed by the various methods of contacting the surface of a plated steel with processing liquid containing chromium, such as chromate chromate and phosphate chromate. Thereby, the said problem is avoided by forming what is generally called a reactive chromate coating on the surface of a plated steel material.

A chromate treatment containing hexavalent chromium has been adopted in the industry as a chromate treatment method among the preventing rusting methods of metal surfaces. In recent years, regulations on substances that are harmful to the environment and humans are being strengthened, and hexavalent chromium, which is indicated to be carcinogenic, is also targeted. Is being developed.

A film obtained by contacting a treatment solution of a trivalent chromium main body which does not contain hexavalent chromium on a zinc plating, and has corrosion resistance equivalent to that of a chromate treatment film containing a conventional hexavalent chromium as a main component, and furthermore Has proposed a coating having a corrosion resistance far exceeding a conventional coating of hexavalent chromium as a main component, a treatment solution thereof, and a method of forming the same.

However, the trivalent chromium ion contained in the trivalent chromium plating solution has a very complex coordination chemical structure in an aqueous solution, and has a problem in that chromium plating layer is difficult to form due to low reactivity. In particular, the formation of the chemical conversion film of trivalent chromate exists as a dark blue ion coordinated with 6 molecules of water when dissolved in water as the main raw materials such as CrCl ₃ and Cr (NO ₃ ) ₃ . There is a problem that a trihydroxy complex is formed.

In particular, torque adjusters are sometimes needed when processing bolts and nuts. The coefficient of friction tends to be slightly higher than the chromate coating, but the difference in the plating bath is larger. In other words, the plating film of the acid chloride bath tends to have a lower coefficient of friction than the alkaline film. In the case of painting after the trivalent chromate treatment, there is a problem in the adhesion of the coating film. Inorganic acid type coating with added colloidal has a gentle two-layer structure in which a mixture of silica and chromium and chromium is formed in the upper layer, which results in a gentle two-layer structure. Thus, particles derived from the surface layer may adversely affect the adhesion of the coating layer.

In particular, in the case of the conventional trivalent chromate treatment, it is necessary to immerse and use 60 seconds or more at 40 to 100 ° C. for treatment temperature and time, and thus it is necessary to improve such treatment conditions.

Korean Patent Publication No. 10-2002-0051210 (published 2002.06 28) Korean Patent Registration No. 10-0370472 (Notice date 2003.04.10)

The present inventors have made efforts to improve the chromate treatment process of the existing galvanized product, the present invention is to know the optimal composition and composition ratio of the color trivalent chromate treatment solution for zinc plating that can prevent the corrosion resistance of the galvanized product, the occurrence of white rust To complete. That is, the present invention is to provide a colored trivalent chromate treatment solution for galvanizing, a method for preparing the same, and a method for chromate treating a galvanized product using the same.

The present invention for solving the above problems relates to a method for preparing a colored trivalent chromate treatment solution for zinc plating, to prepare a solution by mixing and dissolving trivalent chromium precursor, cobalt precursor, sulfuric acid, nitric acid, fluorine precursor and water. Stage 1; 2 steps to cool the solution to 10 ~ 35 ℃; 3 steps of preparing a reaction solution by adding, stirring and reacting the organic acid to the cooled solution; And four steps of filtering the reaction solution. A colored trivalent chromate treatment solution may be prepared.

Another object of the present invention is a colored trivalent chromate treatment solution prepared by the above method, 10 to 30% by weight of trivalent chromium precursor, 1 to 15% by weight of cobalt precursor, 1 to 10% by weight of sulfuric acid, 1 to 10% by weight of nitric acid , 1 to 5% by weight of the fluorine precursor, 5 to 15% by weight of the organic acid and the remaining amount of water may be characterized.

Another object of the present invention relates to a method of chromate treating a galvanized product using the colored trivalent chromate treatment solution, comprising: preparing a mixture of a colored trivalent chromate treatment solution and water; Two steps of drying and galvanizing the galvanized product in the mixture; And three steps of drying the chromate-treated galvanized product to perform chromatic chromate treatment on the surface of the galvanized product.

Color trivalent chromate treatment solution for zinc plating of the present invention can be chromate treatment at a rapid time at room temperature to improve the economics, not only to prevent corrosion resistance and white blue of the galvanized products, trivalent chromate coating layer The excellent adhesion (adhesiveness) to the galvanized and can improve the long-term life of the galvanized product.

1 is a photograph of a galvanized product chromated with a colored trivalent chromate treatment solution for galvanizing.

Hereinafter, the present invention will be described in more detail.

The colored trivalent chromate treatment solution for zinc plating of the present invention comprises a step 1 of preparing a solution by mixing and dissolving trivalent chromium precursor, cobalt precursor, sulfuric acid, nitric acid, fluorine precursor and water; 2 steps to cool the solution to 10 ~ 35 ℃; 3 steps of preparing a reaction solution by adding, stirring and reacting the organic acid to the cooled solution; And four steps of filtering the reaction solution.

Mixing and dissolving the composition for preparing the solution in step 1 may be carried out at 5 ~ 40 ℃ and under normal pressure, preferably 10 ~ 35 ℃ and under normal pressure, more preferably 15 ~ 30 ℃ and under normal pressure You can do it.

In the first step, when the trivalent chromium precursor, cobalt precursor, sulfuric acid, nitric acid, and fluorine precursor are completely dissolved in water, the temperature of the solution is increased to 70 to 90 ° C., preferably 75 to 85 ° C. at the completion of dissolution. . Therefore, it is preferable to cool the solution prepared in step 1 again to room temperature (10 to 35 ° C).

In the third step, the organic acid is added to the cooled solution, stirred, and reacted to prepare a strong acid having a pH of 3.0 or less, preferably pH 1.0 to 2.8. In this case, when the acidity of the preparation is too low, there may be a problem of solution stability, such as the formation of a precipitate when the solution is stored. When the colored trivalent chromate treatment solution and water are mixed to chromate treatment of the appropriate galvanized product, when the pH of the reaction solution exceeds 2.8, when the chromate treatment is performed, the appropriate pH of the chromate treatment solution is 1.8 to 3.0. There may be a problem that is difficult to match.

In addition, the four-step filtration is a process for removing unreacted substances and impurities in the reaction solution, it is possible to use a general filtration method used in the art, it is preferable to perform the filtration using a filter of the appropriate size, More preferably, it is preferable to use a filter within a pore size of 1 μm, which filters out impurities and foreign substances remaining in the solution and prevents large particles of impurities from reacting to crystallization.

The trivalent chromium precursor used in the preparation of the colored trivalent chromate treatment solution of the present invention is discontinued selected from CrCl ₃ 6H ₂ O, Cr ₂ (SO ₄ ) ₃ 6H ₂ O, and Cr (NO ₃ ) ₃ ㆍ 9H ₂ O. Or two or more kinds can be used, and preferably, one or two or more kinds selected from CrCl ₃ .6H ₂ O and Cr ₂ (SO ₄ ) ₃ .6H ₂ O can be used. In addition, the content of the trivalent chromium precursor may include 10 to 30% by weight, preferably 15 to 30% by weight, more preferably 22 to 28% by weight of the total weight of the colored trivalent chromate treatment solution. In this case, when the content of the trivalent chromium precursor is less than 10% by weight, the corrosion resistance of the chromate-treated galvanized product may not be sufficiently secured. If the content of the trivalent chromium precursor is more than 30% by weight, the solution may be supersaturated and precipitated or chromate color may be degraded. It may be included as the content within the above range.

In addition, the cobalt precursor plays a role of improving corrosion resistance along with the trivalent chromium precursor, and is selected from Co (NO ₃ ) ₂ .6H ₂ O, CoSO ₄ .7H ₂ O and CoCl ₂ .6H ₂ O. It is possible to use, preferably one or two or more selected from Co (NO ₃ ) ₂ .6H ₂ O and CoSO ₄ .7H ₂ O can be used. In addition, the content of the cobalt precursor may include 1 to 15% by weight, preferably 2 to 12% by weight, and more preferably 4 to 9.5% by weight of the total weight of the colored trivalent chromate treatment liquid. At this time, if the content of the cobalt precursor is less than 1% by weight may not ensure the corrosion resistance of the chromate-treated galvanized product, if the content of more than 15% by weight may be a problem that the implementation of chromate color is lower than the content within the above range It is good to include.

In addition, the sulfuric acid and nitric acid serves to prevent precipitation and degradation of the treatment liquid due to unnecessary reaction between components in the colored trivalent chromate treatment solution, each of the sulfuric acid and nitric acid content of the total weight of the colored trivalent chromate treatment solution It is preferable to use 1 to 10% by weight, preferably 1 to 7% by weight, more preferably 2 to 6% by weight. At this time, if the content of sulfuric acid is less than 1% by weight or more than 10% by weight of the total weight of the trivalent chromate treatment solution, the corrosion resistance and the film formation rate may be lowered. In addition, when the content of nitric acid is less than 1% by weight or more than 10% by weight of the total weight of the trivalent chromate treatment solution, a problem may occur in that the galvanized (coated body) film is sharply cut off. And, as an acid component, the reason for using the mixture rather than using sulfuric acid or nitric acid alone is to use sulfuric acid in order to minimize the environmental problems caused by nitric acid, and advantageous in terms of chromate color implementation and surface etching Because. And, it is preferable to use less sulfuric acid than the amount of nitric acid used, it is good to use so that the weight ratio of nitric acid and sulfuric acid 1: 1: 0.3 ~ 0.8 weight ratio.

In addition, the fluorine precursor is a complexing agent of the colored trivalent chromate treatment solution to ensure stability and film retention, and mixed with one or two or more selected from NaF, KF, CaF ₂ , NH ₄ F and NH ₄ HF ₂ . It may be used, or preferably selected from NaF, NH ₄ F and NH ₄ HF ₂ or a mixture of two or more thereof may be used. In addition, the content of the fluorine precursor may include 1 to 5% by weight, preferably 1.5 to 4% by weight of the total weight of the colored trivalent chromate treatment solution. At this time, if the content of the fluorine precursor is less than 1% by weight may have a problem that it is difficult to secure the film maintenance stability of the chromate treatment solution, when the content of more than 5% by weight may be a problem of surface color implementation, corrosion resistance degradation content in the above range It is good to include as.

The organic acid serves to adjust the pH of the chromate treatment liquid related to the generation of insoluble salts, and to improve the glossiness of the chromate coating after chromate treatment, and may use a general organic acid used in the art, preferably male Or disperse one or two or more selected from acids, oxalic acid, malonic acid, succinic acid, formic acid, acetic acid, citric acid, propionic acid, butyric acid, adipic acid, glycolic acid vanadil and dihydroascorbic acid vanadil. May be used singly or in mixture of two or more selected from acetic acid, citric acid and maleic acid. In addition, the content of the organic acid may be 5 to 15% by weight, preferably 6 to 12% by weight of the total weight of the colored trivalent chromate treatment liquid. At this time, if the content of the organic acid is less than 5% by weight it may be difficult to adjust the appropriate pH of the chromate treatment solution 1.8 ~ 3, when used in excess of 15% by weight of the coating color implementation is reduced, the color and gloss of the chromate coating There may be a problem falling.

The colored trivalent chromate treatment solution for galvanizing prepared includes water in addition to trivalent chromium precursor, cobalt precursor, sulfuric acid, nitric acid, fluorine precursor, and organic acid in 100 wt%, and the colored trivalent chromate treatment for galvanizing prepared The pH of the liquid may be 1 to 2.8, preferably pH 1.5 to 2.6.

Next, a method of chromate treating a galvanized product using the colored trivalent chromate treatment solution for zinc plating prepared by the method described above will be described.

The method for chromate treating the galvanized product of the present invention comprises the steps of preparing a mixture of the above-mentioned colored trivalent chromate treatment solution and water; Two steps of drying and galvanizing the galvanized product in the mixture; And three steps of drying the chromate-treated galvanized product.

The mixture of the first step may include 7 to 14% by volume of the trivalent chromate treatment solution and 86 to 93% by volume of water, and preferably 8 to 12% by volume of the trivalent chromate treatment solution and 88 to 92% by volume of water. More preferably 9 to 11% by volume of the trivalent chromate treatment solution and 89 to 91% by volume of water. At this time, if the content of the trivalent chromate treatment is less than 7% by volume, the thickness of the trivalent chromate film may be too thin, and when the content of the trivalent chromate is more than 14% by volume, overreaction, film color change, and corrosion resistance decrease (if the reaction is long, the film is etched. It may be a problem to produce a mixed solution within the above range.

The mixture thus prepared is pH 1.8 ~ 3.0, preferably pH 2.0 ~ 2.8, more preferably pH 2.0 ~ 2.5, wherein, if the pH of the mixture is less than 1.8, there may be a problem that the film etching is excessive-, pH If is greater than 3.0, there may be a problem that the chromate formation is slow and the color implementation falls.

In addition, the two-step chromate treatment may be performed at 10 to 40 ° C. for 20 to 60 seconds, preferably at 10 to 35 ° C., more preferably at 15 to 32 ° C. for 30 to 55 seconds. At this time, if the temperature is less than 10 ° C chromate treatment, there may be a problem that the chromate treatment time is long, it is uneconomical to exceed 40 ° C. The chromate treatment time is an appropriate treatment time for performing under the above temperature, and is determined according to the treatment temperature.

And, the drying of the three stages can be carried out a general drying method used in the art, for example, can be carried out for 5 to 20 minutes under 60 to 100 ℃, more preferably chromate treatment galvanized products After putting into the oven, it can be carried out for 8 to 15 minutes under 80 ~ 100 ℃.

A trivalent chromate coating layer (or plating layer) having an average thickness of 0.1 μm to 1 μm is formed on the chromate-treated galvanized product thus prepared.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are provided to aid the understanding of the present invention and should not be construed as limiting the scope of the present invention to the following examples.

EXAMPLE

Example 1 Preparation of Trivalent Chromate Treatment Solution for Zinc Plating

At 26 to 27 ° C. and atmospheric pressure, Cr (NO ₃ ) ₃ · 9H ₂ O as a trivalent chromium precursor, CoSO ₄ · 7H ₂ O as a cobalt precursor, sulfuric acid (H ₂ SO ₄ ), nitric acid (HNO ₃ ), and fluorine precursor Phosphorus NH ₄ HF ₂ and distilled water were mixed and then stirred to prepare a solution in which the components were completely dissolved in distilled water. At this time, the temperature of the solution was 80-81 degreeC.

Next, the said solution was left to cool to 29-30 degreeC, and it cooled.

Next, acetic acid, which is an organic acid, was added to the cooled solution, thereby preparing a stirring and reaction solution. At this time, the pH of the prepared reaction solution was 1.85.

Next, the reaction solution was stirred for at least 30 minutes without a precipitate, and then filtered through a pore size 1 μm filter to prepare a colored trivalent chromate treatment solution for zinc plating.

The composition and composition ratio of the prepared colored trivalent chromate treatment solution for zinc plating are shown in Table 1 below.

Example 2-Example 8

To prepare a colored trivalent chromate treatment solution in the same manner as in Example 1, to prepare a colored trivalent chromate treatment solution to have a composition as shown in Table 1, Examples 2 to 8, respectively.

Comparative Example 1 to Comparative Example 8

To prepare a colored trivalent chromate treatment solution in the same manner as in Example 1, to prepare a colored trivalent chromate treatment solution to have a composition as shown in Tables 2 to 3, respectively, Comparative Examples 1 to 8.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Trivalent chrome
Precursor Cr (NO ₃ ) ₃ ㆍ 9H ₂ O 24.2
weight% 29
weight% 15
weight% 24.2
weight% 24.2
weight% 24.2
weight% 24.2
weight% 24.2
weight% cobalt
Precursor CoSO ₄ 7H ₂ O 5.7
weight% 5.7
weight% 5.7
weight% 2
weight% 12
weight% 5.7
weight% 5.7
weight% 5.7
weight% Sulfuric acid 3.8
weight% 3.8
weight% 3.8
weight% 3.7
weight% 3.8
weight% 2.3
weight% 3.8
weight% 3.8
weight% nitric acid 4.2
weight% 4.2
weight% 4.2
weight% 4.1
weight% 4.2
weight% 6.0
weight% 4.2
weight% 4.2
weight% Fluoride
Precursor NH ₄ HF ₂ 3.9
weight% 3.9
weight% 3.9
weight% 3.9
weight% 3.9
weight% 3.9
weight% 1.5
weight% 4.5
weight% Organic acid Acetic acid 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% Distilled water Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Trivalent Chromate
Treatment Fluid pH 2.2 2.2 2.1 2.2 2.2 1.9 2.0 2.3

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Trivalent chrome
Precursor Cr (NO ₃ ) ₃ ㆍ 9H ₂ O 9.2
weight% 31.5
weight% 24.2
weight% 24.2
weight% 24.2
weight% 24.2
weight% 24.2
weight% 24.2
weight% cobalt
Precursor CoSO ₄ 7H ₂ O 5.7
weight% 5.7
weight% 0.6
weight% 16.5
weight% 5.7
weight% 5.7
weight% 5.7
weight% 5.7
weight% Sulfuric acid 3.8
weight% 3.8
weight% 3.8
weight% 3.7
weight% - 3.7
weight% 3.8
weight% 3.8
weight% nitric acid 4.2
weight% 4.2
weight% 4.2
weight% 4.1
weight% 8.5
weight% 4.1
weight% 4.2
weight% 4.2
weight% Fluoride
Precursor NH ₄ HF ₂ 3.9
weight% 3.9
weight% 3.9
weight% 3.9
weight% 3.9
weight% 0.5
weight% 5.5
weight% 3.9
weight% Organic acid Acetic acid 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 6.8
weight% 16
weight% Distilled water Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Remainder
Remaining amount Trivalent Chromate
Treatment Fluid pH 2.3 2.2 2.2 2.2 1.8 1.9 2.4 2.1

Preparation Example 1 Chromate Treatment of Galvanized Steel Products

A zinc plated product having a thickness of 8 μm prepared by zinc electroplating was prepared.

After the trivalent chromate treatment solution for zinc plating prepared in Example 1 and distilled water was mixed at 10: 90% by volume, this was added to a dry bath. The pH of the mixed liquid in the drying bath was 2.36.

Next, the galvanized product was put in a dry bath, and then subjected to a chromate treatment for 45 seconds at 33 ° C. in an air stirred solution.

Next, after washing with water, the chromate-treated galvanized product was put in an oven, and dried at 85 ° C. for 5 to 20 minutes to prepare a chromate-galvanized product. The average thickness of the trivalent chromate film of the manufactured galvanized product was 0.38 μm. Its photograph is shown in FIG. 1.

Preparation Examples 2 to 10 and Comparative Preparation Examples 1 to 8

Chromate treatment of the galvanized product having the same spec of Preparation Example 1 in the same manner as in Preparation Example 1, but instead of the chromate treatment solution of Example 1, using the chromate treatment solution of Examples and Comparative Examples as shown in Table 3 below The galvanized product was subjected to chromate treatment.

In addition, Production Examples 9 to 10 and Comparative Production Examples 9 to 10 are chromate treatment liquids: distilled water.

Chromatization was performed by varying the volume ratio as shown in Table 4 below.

division Chromate
Treatment solution Chromate Treatment Liquid: Distilled Water Volume Ratio Chromate Treatment Condition film
color Mixed solution pH Treatment temperature / hour Preparation Example 1 Example 1 10:90 2.2 25 ℃ / 30 seconds Colored Preparation Example 2 Example 2 10:90 2.2 25 ℃ / 30 seconds Colored Preparation Example 3 Example 3 10:90 2.1 25 ℃ / 30 seconds Colored Preparation Example 4 Example 4 10:90 2.2 25 ℃ / 30 seconds Colored Preparation Example 5 Example 5 10:90 2.2 25 ℃ / 30 seconds Pale colored Preparation Example 6 Example 6 10:90 1.9 25 ℃ / 30 seconds Dark color Preparation Example 7 Example 7 10:90 2.0 25 ℃ / 30 seconds Pale colored Preparation Example 8 Example 8 10:90 2.3 25 ℃ / 30 seconds Dark color Preparation Example 9 Example 1 5:95 2.5 25 ℃ / 30 seconds Pale colored Preparation Example 10 Example 1 20:80 1.8 25 ℃ / 30 seconds Dark color Comparative Production Example 1 Comparative Example 1 10:90 2.3 25 ℃ / 30 seconds Pale colored Comparative Production Example 2 Comparative Example 2 10:90 2.2 25 ℃ / 30 seconds Pale colored Comparative Production Example 3 Comparative Example 3 10:90 2.2 25 ℃ / 30 seconds Colored Comparative Production Example 4 Comparative Example 4 10:90 2.2 25 ℃ / 30 seconds Light colored Comparative Production Example 5 Comparative Example 5 10:90 1.8 25 ℃ / 30 seconds Dark color Comparative Production Example 6 Comparative Example 6 10:90 1.9 25 ℃ / 30 seconds Pale colored Comparative Production Example 7 Comparative Example 7 10:90 2.4 25 ℃ / 30 seconds Dark color Comparative Production Example 8 Comparative Example 8 10:90 2.1 25 ℃ / 30 seconds Dark color Comparative Production Example 9 Example 1 4: 96 2.5 25 ℃ / 30 seconds Pale colored Comparative Production Example 10 Example 1 25: 75 1.7 25 ℃ / 30 seconds Dark color

Experimental Example 1: Measurement of physical properties such as corrosion resistance and corrosion resistance

(1) Corrosion resistance of the chromate-treated galvanized product prepared in Preparation Example and Comparative Preparation Example was measured based on KS d 9502 (Salt spray test) method, and the results are shown in Table 4 below.

(2) The surface appearance corrosion of the chromate-treated galvanized product prepared in Preparation Example and Comparative Preparation Example was measured based on KS D 9502 (Salt spray test) method, and the results are shown in Table 4 below.

division Corrosion resistance
(time) Corrosion resistance measurement (determination of appearance visually based on 240 hours, red rust occurrence) Preparation Example 1 240 No red rust Preparation Example 2 240 No red rust Preparation Example 3 216 No red rust Preparation Example 4 216 No red rust Preparation Example 5 240 No red rust Preparation Example 6 216 No red rust Preparation Example 7 240 No red rust Preparation Example 8 240 No red rust Preparation Example 9 200 Red rust occurs after 200 hours Preparation Example 10 156 Red rust occurs after 150 hours Comparative Production Example 1 96 Red rust occurs more than 100 hours ago Comparative Production Example 2 120 Red rust occurs over 150 hours Comparative Production Example 3 96 Red rust occurs more than 100 hours ago Comparative Production Example 4 120 Red rust occurs over 150 hours Comparative Production Example 5 72 Red rust occurs more than 100 hours ago Comparative Production Example 6 120 Red rust occurs over 150 hours Comparative Production Example 7 72 Red rust occurs more than 100 hours ago Comparative Production Example 8 96 Red rust occurs more than 100 hours ago Comparative Production Example 9 120 Red rust occurs over 150 hours Comparative Production Example 10 72 Red rust occurs more than 100 hours ago

Looking at the corrosion resistance and corrosion resistance measurement results of Table 4, in the case of Preparation Examples 1 to 10, showed a corrosion resistance measurement result of 156 hours or more, the salt rust test results of no red rust within 240 hours, excellent corrosion resistance measurement results Seemed.

On the other hand, in the case of Comparative Production Examples 1 to 10, there was a problem showing low corrosion resistance and corrosion resistance as compared with the production examples.

Claims (12)

15 to 30 wt% trivalent chromium precursor, 4 to 9.5 wt% cobalt precursor, 1 to 7 wt% sulfuric acid, 1 to 7 wt% nitric acid, 1.5 to 4 wt% fluorine precursor, 5 to 15 wt% organic acid and residual water 1 step of preparing a solution by mixing and dissolving;
2 steps to cool the solution;
Preparing a reaction solution having a pH of 1.0 to 2.8 by adding, stirring, and reacting an organic acid to the cooled solution; And
And four steps of filtering the reaction solution.
The melting solution of the first stage has a temperature of 70 ~ 90 ℃ of the solution at the time when dissolution is completed,
The trivalent chromium precursor includes at least one selected from CrCl ₃ .6H ₂ O, Cr ₂ (SO ₄ ) ₃ .6H ₂ O, and Cr (NO ₃ ) ₃ .9H ₂ O.
The cobalt precursor includes at least one selected from Co (NO ₃ ) ₂ .6H ₂ O, CoSO ₄ .7H ₂ O and CoCl ₂ .6H ₂ O.
The fluorine precursor includes at least one selected from NaF, KF, CaF ₂ , NH ₄ F and NH ₄ HF ₂ ,
The organic acid is characterized in that it comprises one or more selected from maleic acid, oxalic acid, malonic acid, succinic acid, formic acid, acetic acid, citric acid, propionic acid, butyric acid, adipic acid, glycolic acid vanadil and dihydroascorbic acid vanadil. A method for producing a colored trivalent chromate treatment solution for galvanizing. delete delete delete delete delete delete delete delete A first step of preparing a mixture of 7 to 14% by volume of the colored trivalent chromate treatment solution prepared by the method of claim 1 and 86 to 93% by volume of water;
Two steps of drying and galvanizing the galvanized product in the mixture; And
Three steps of drying the chromate-treated galvanized product; including,
Two-step chromate treatment is carried out for 20 to 60 seconds under the pH 2.0 to 2.8 and 10 to 40 ℃ of the mixture,
The drying in three steps is chromate treatment method of galvanized product, characterized in that performed for 5 to 20 minutes at 60 ~ 100 ℃. delete delete

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