CN116180063A - Zinc-nickel alloy trivalent chromium color passivating agent, preparation method and passivating method thereof - Google Patents

Abstract

The invention provides a zinc-nickel alloy trivalent chromium color passivator, a preparation method and a passivation method thereof. The zinc-nickel alloy trivalent chromium color passivating agent provided by the invention comprises 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanium oxysulfate, 1-10 parts of nickel fluoride, and acetic acid in parts by weight. 1-15 parts of sodium, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid and 1-10 parts of nitric acid. The zinc-nickel alloy trivalent chromium color passivation agent provided by the present invention forms a chromium-titanium-nickel passivation film to obtain a full red and bright color, and at the same time, the white rust time of the neutral salt spray test is more than 240 hours.

Description

Zinc-nickel alloy trivalent chromium color passivator and its preparation method and passivation method

technical field

The invention belongs to the technical field of trivalent chromium color passivation, and in particular relates to a zinc-nickel alloy trivalent chromium color passivator, a preparation method and a passivation method thereof.

Background technique

With the development of industrial technology, the anti-corrosion requirements for metal workpieces are getting higher and higher, especially in harsh environments, conventional anti-corrosion methods, such as bluing, galvanizing, galvanizing, etc., can no longer meet the long-term anti-corrosion requirements of workpieces. The electroplating zinc-nickel alloy technology has excellent corrosion resistance and low hydrogen embrittlement, and the process flow is equivalent to that of electro-galvanizing, so it is loved by various manufacturers.

The passivation of existing zinc-nickel alloys generally includes natural color, blue and white, colored and black. Black passivation For example, patent application number 201810434850.0 discloses a zinc-nickel alloy trivalent chromium black passivation solution and its preparation method. Natural color passivation For example, patent application number 201410741396.5 discloses a trivalent chromium high corrosion-resistant natural color passivator for zinc-nickel alloys. After passivation, it presents a silver-white appearance, but the natural color passivation is relatively small. In addition to black and natural colors, there are also more blue and white passivation processes. In addition, there are many reports on zinc-nickel alloy iridescent passivation, mainly because trivalent chromium salts are generally green and hexavalent chromium salts are orange-yellow, and the passivation film will scatter light. The interference of light creates iridescence.

Zinc-nickel alloy color passivation is also currently being studied. Although zinc-nickel alloy color passivation has been developed to a certain extent, it is still difficult to achieve better color and salt spray effects for red passivation. The current red passivation generally has the disadvantages that the color is not red enough and the color is not bright enough, which limits the application in many fields with high appearance requirements. Therefore, how to solve the color effect and salt spray effect of red passivation is an important breakthrough for those skilled in the art.

Contents of the invention

Aiming at the deficiencies of the prior art, the invention provides a full-red and bright zinc-nickel alloy trivalent chromium color passivator, a preparation method and a passivation method thereof.

The invention provides a zinc-nickel alloy trivalent chromium color passivator, which comprises 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanium oxysulfate, 1-10 parts of nickel fluoride, 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid, and 1-10 parts of nitric acid.

Preferably, by weight, 20-25 parts of chromium nitrate, 4-8 parts of titanium trichloride or titanyl sulfate.

Preferably, in parts by weight, the nickel fluoride is 4-6 parts, and sodium acetate is 5-8 parts.

Preferably, in parts by weight, 2-5 parts of malonic acid, 1-3 parts of glacial acetic acid, and 1-3 parts of nitric acid.

The present invention also provides a zinc-nickel alloy trivalent chromium color passivator, which consists of 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanium oxysulfate, and 1-10 parts of nickel fluoride in parts by weight. , 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid and 1-10 parts of nitric acid.

The present invention also provides a preparation method of a zinc-nickel alloy trivalent chromium color passivator, comprising the steps of:

S1. Add part of deionized water into the container and heat to 75-80°C;

S2. Ensure that chromium nitrate is added at 75-80°C, and fully stirred until completely dissolved;

S3, then sequentially add nickel fluoride, sodium acetate and malonic acid, keep warm at a temperature of 75-80°C, and stir for 40-80 minutes;

S4. After cooling the solution in step S3 to 40-60°C, add titanium trichloride or titanyl sulfate, and stir thoroughly;

S5. After cooling the solution in step S4 to room temperature, add glacial acetic acid and nitric acid, and stir thoroughly;

S6. Add the remaining deionized water and stir evenly.

Preferably, in step S3, stirring is carried out for 40-70 minutes.

Preferably, in the step S4, after cooling down to 45-50° C., titanium trichloride or titanyl sulfate is added.

The present invention also provides a zinc-nickel alloy passivation method, comprising the steps of:

After the workpiece is electroplated with zinc-nickel alloy, it is passivated with the zinc-nickel alloy trivalent chromium color passivator for 20-50 seconds, then washed with water, and baked at 60-80° C. for 15 minutes after washing with water.

Preferably, the passivation time is 30-40 seconds.

The zinc-nickel alloy trivalent chromium color passivation agent provided by the invention forms a chromium-titanium-nickel passivation film to obtain a full red bright color, and at the same time, the white rust time of the neutral salt spray test is more than 240 hours.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with specific examples, so that those skilled in the art can better understand the present invention and implement it, but the examples given are not intended to limit the present invention.

An embodiment of the present invention provides a zinc-nickel alloy trivalent chromium color passivator, which comprises 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanium oxysulfate, and 1-10 parts of nickel fluoride in parts by weight. 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid, and 1-10 parts of nitric acid.

In a preferred embodiment, by weight, 20-25 parts of chromium nitrate; more preferably 22-24 parts.

In a preferred embodiment, by weight, 4-8 parts of titanium trichloride or titanium oxysulfate; more preferably 5-7 parts.

In a preferred embodiment, by weight, 4-6 parts of nickel fluoride, 5-8 parts of sodium acetate, 2-5 parts of malonic acid, 1-3 parts of glacial acetic acid, and 1-3 parts of nitric acid.

The embodiments of the present invention provide a zinc-nickel alloy trivalent chromium color passivator, which consists of 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanium oxysulfate, and 1-10 parts of nickel fluoride in parts by weight. 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid and 1-10 parts of nitric acid.

Embodiments of the present invention also provide the preparation method of the zinc-nickel alloy trivalent chromium color passivator mentioned in any of the above embodiments, comprising the following steps:

S1. Add part of deionized water into the container and heat to 75-80°C;

S2. Ensure that chromium nitrate is added at 75-80°C, and fully stirred until completely dissolved;

S3, then add nickel fluoride, sodium acetate and malonic acid in sequence, keep warm at a temperature of 75-80°C, and stir for 40-80 minutes, preferably 40-70 minutes.

S4. After cooling the solution in step S3 to 40-60°C, preferably 45-50°C, add titanium trichloride or titanyl sulfate, and stir thoroughly;

S5, after cooling the solution in step S4 to room temperature, add glacial acetic acid and nitric acid, and fully stir;

S6. Add the remaining deionized water and stir evenly.

The embodiment of the present invention also provides a zinc-nickel alloy passivation method, comprising the following steps:

After electroplating the workpiece with zinc-nickel alloy, use the zinc-nickel alloy trivalent chromium color passivator mentioned in any embodiment to passivate for 20-50 seconds, then wash with water, and bake at 60-80° C. for 15 minutes after washing.

In a preferred embodiment, the passivation is performed for 30-40 seconds.

In order to have a further understanding and understanding of the technical solution of the present invention, several preferred embodiments are listed to further describe it in detail.

Example 1

Preparation of passivating agent:

Take 1L as an example:

(1) Put 0.5L of deionized water in a container with a capacity of 1L and heat it to 75-80°C;

(2) Add 22g of chromium nitrate while hot, fully stir until fully dissolved;

(3) Add 5g/L nickel fluoride, 7g/L sodium acetate, and 4g/L malonic acid successively, keep warm at a temperature of 80°C, and stir for 60 minutes;

(4) After cooling the solution in step (3) to 47°C, add 6g/L titanium trichloride (or titanyl sulfate), and stir thoroughly;

(5) After the solution of step (4) is cooled to normal temperature, add 2g/L glacial acetic acid, 2g/L nitric acid, fully stir;

(6) Finally add deionized water to 1L, stir evenly to obtain zinc-nickel alloy trivalent chromium color passivator.

After electroplating the workpiece with zinc-nickel alloy, wash it with water, passivate it with a zinc-nickel alloy trivalent chromium color passivator at room temperature for 35 seconds, and bake it at 70°C for 15 minutes after washing with water.

Through observation, it is found that after the passivation in this embodiment, a chromium-titanium-nickel passivation film is formed on the zinc-nickel alloy coating, the appearance is bright and full red, and it does not contain hexavalent chromium, which meets the environmental protection requirements. The workpiece after passivation in this embodiment was subjected to a neutral salt spray test according to GB/T 6461-2002 and GB/T 10125-1997, and the salt spray time exceeded 240 hours, which had a very significant salt spray effect.

The above is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the content of the description of the present invention, or directly or indirectly used in other related technical fields, All are included in the scope of patent protection of the present invention in the same way.

Claims (10)

1. The zinc-nickel alloy trivalent chromium color passivating agent is characterized by comprising, by weight, 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanyl sulfate, 1-10 parts of nickel fluoride, 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid and 1-10 parts of nitric acid.

2. The zinc-nickel alloy trivalent chromium color passivation agent according to claim 1, wherein the chromium nitrate is 20-25 parts by weight, titanium trichloride or titanyl sulfate is 4-8 parts by weight.

3. The zinc-nickel alloy trivalent chromium color passivation agent according to claim 1, wherein the nickel fluoride is 4-6 parts by weight and the sodium acetate is 5-8 parts by weight.

4. The zinc-nickel alloy trivalent chromium color passivation agent according to claim 1, wherein the malonic acid is 2-5 parts, glacial acetic acid is 1-3 parts, and nitric acid is 1-3 parts by weight.

5. The zinc-nickel alloy trivalent chromium color passivating agent is characterized by comprising, by weight, 10-30 parts of chromium nitrate, 1-10 parts of titanium trichloride or titanyl sulfate, 1-10 parts of nickel fluoride, 1-15 parts of sodium acetate, 1-10 parts of malonic acid, 1-10 parts of glacial acetic acid and 1-10 parts of nitric acid.

6. The method for preparing the zinc-nickel alloy trivalent chromium color passivation agent according to any one of claims 1-5, comprising the following steps:

s1, adding part of deionized water into a container, and heating to 75-80 ℃;

s2, adding chromium nitrate at 75-80 ℃ and fully stirring until the chromium nitrate is completely dissolved;

s3, sequentially adding nickel fluoride, sodium acetate and malonic acid, preserving heat at 75-80 ℃, and stirring for 40-80 minutes;

s4, cooling the solution obtained in the step S3 to 40-60 ℃, adding titanium trichloride or titanyl sulfate, and fully stirring;

s5, cooling the solution obtained in the step S4 to room temperature, adding glacial acetic acid and nitric acid, and fully stirring;

s6, adding the rest deionized water, and uniformly stirring.

7. The process according to claim 6, wherein in step S3, the mixture is stirred for 40 to 70 minutes.

8. The method according to claim 6, wherein in the step S4, the temperature is lowered to 45-50 ℃, and then titanium trichloride or titanyl sulfate is added.

9. The zinc-nickel alloy passivation method is characterized by comprising the following steps of:

after the zinc-nickel alloy is electroplated on the workpiece, passivating is carried out for 20-50 seconds by using the zinc-nickel alloy trivalent chromium color passivating agent according to any one of claims 1-5, then washing is carried out, and baking is carried out for 15 minutes at 60-80 ℃ after washing.

10. A method of passivating a zinc-nickel alloy according to claim 9, wherein the passivating is carried out for a period of time in the range of 30 to 40 seconds.