Titanium metal stripping solution based on composite acid system and application of titanium metal stripping solution

Abstract

The invention discloses a titanium metal stripping solution based on a composite acid system and application of the titanium metal stripping solution, and belongs to the technical field of alloy surface treatment.The titanium metal stripping solution is prepared from, by weight, 10-15 parts of hydrofluoric acid, 3-5 parts of hydrochloric acid, 1-1.5 parts of sulfuric acid, 1-1.2 parts of hydrogen peroxide, 2-5 parts of corrosion inhibitor and 80-85 parts of deionized water; compared with a traditional single acid system, the deplating speed is increased by 3-5 times, nitric acid is avoided, emission of more than 90% of harmful gas is reduced, the passivation effect of hydrogen peroxide and the corrosion inhibitor can control the corrosion depth (the surface roughness is smaller than or equal to 0.8 micrometer), and efficient deplating can be achieved through a tetrabasic acid system.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy and gold surface treatment, and in particular to a titanium metal stripping solution based on a composite acid system and application thereof. Background Art

[0002] Stripping solution is a chemical liquid that can effectively remove a layer of special metal or metal material coating on the surface of various workpieces through immersion, heating, ultrasound, electrolysis, etc., without dissolving, corroding or changing the color of the workpiece substrate. In this sense, there are many types of stripping solutions. At present, the country or the industry has not made a clearly defined classification method and scope for stripping solutions. It is only the production research and development institutions and production enterprises that have conventionally given the range of stripping solutions according to the substrate of the workpiece to be stripped.

[0003] Titanium is widely used in aerospace, medical devices, and other fields due to its high corrosion resistance. However, the removal of surface coatings (such as electroplated layers and oxide films) presents technical challenges. Traditional titanium stripping processes often utilize high-concentration hydrofluoric acid or nitric acid systems, which have the following disadvantages: 1. Nitric acid easily decomposes toxic nitric oxide and nitrogen dioxide gases, which harm the environment; 2. The wastewater from nitric acid stripping contains a large amount of heavy metal products. Due to its strong oxidizing properties, nitric acid is difficult to recycle and reuse, resulting in a waste of resources. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention provides a titanium metal stripping solution based on a composite acid system and applications thereof to solve the problems in the background technology.

[0005] The object of the present invention is achieved as follows: A titanium metal stripping solution based on a composite acid system comprises the following raw materials in parts by weight: 10-15 parts of hydrofluoric acid, 3-5 parts of hydrochloric acid, 1-1.5 parts of sulfuric acid, 1-1.2 parts of hydrogen peroxide, 2-5 parts of corrosion inhibitor, and 80-85 parts of deionized water; Hydrofluoric acid can react with titanium oxide to form soluble fluorotitanate.

[0006] Hydrochloric acid provides H + Accelerate the reaction and dissolve the passivation film on the surface of the titanium substrate.

[0007] Sulfuric acid improves solution stability and inhibits the generation of side reaction gases.

[0008] Hydrogen peroxide can act as an oxidant and system corrosion inhibitor to promote the conversion of titanium oxide layer into more soluble high-valent compounds.

[0009] The tetrabasic acid system achieves efficient stripping through the following mechanisms: Hydrofluoric acid and hydrogen peroxide synergistically destroy the TiO2 passivation layer (reaction formula: TiO2+ 6HF → H2TiF6+ 2H2O).

[0010] Hydrochloric acid provides chloride ions to form a complex with titanium to accelerate dissolution.

[0011] Sulfuric acid prolongs the contact time of the reactants by increasing the viscosity of the solution.

[0012] The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 65-70°C while stirring, keep warm and react for 1 hour, add sodium hydroxide aqueous solution dropwise after the reaction, continue to heat to 80°C, reflux reaction for 6-8 hours, and perform post-treatment after the reaction to obtain a corrosion inhibitor.

[0013] The secondary ammonia on benzotriazole reacts with n-dodecane bromide to prepare a corrosion inhibitor.

[0014] Furthermore, the dosage ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.02-0.05 mol: 0.02-0.05 mol: 0.25-0.3 g: 20 mL: 30-50 mL.

[0015] Furthermore, the mass fraction of the sodium hydroxide aqueous solution is 50%.

[0016] Furthermore, the specific steps of the post-treatment are: first separating the oil layer, extracting the water layer with toluene, combining the organic phases, washing with deionized water until neutral, drying, and rotary evaporation.

[0017] Furthermore, the drying temperature is 60-80°C.

[0018] Furthermore, the mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

[0019] Furthermore, the titanium metal stripping solution is prepared by the following steps: Add deionized water to an acid-resistant container, then slowly add hydrofluoric acid, stir uniformly at a speed of 150-200 r / min, add hydrochloric acid and concentrated sulfuric acid, continue stirring and cool to 5-10°C, add hydrogen peroxide, and finally add corrosion inhibitor to prepare a titanium metal stripping solution.

[0020] The invention discloses a titanium metal stripping solution based on a composite acid system, which is used for titanium alloy surface treatment.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the present invention prepares a titanium metal stripping solution, which increases the stripping speed by 3-5 times compared with the traditional single-acid system, avoids the use of nitric acid, reduces harmful gas emissions by more than 90%, and the passivation effect of hydrogen peroxide and corrosion inhibitor can control the corrosion depth (surface roughness ≤ 0.8μm), and can achieve efficient stripping through the tetrabasic acid system. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Example 1: A titanium metal stripping solution based on a composite acid system, characterized in that it comprises the following raw materials in parts by weight: 10 parts hydrofluoric acid, 3 parts hydrochloric acid, 1 part sulfuric acid, 1 part hydrogen peroxide, 2 parts corrosion inhibitor, and 80 parts deionized water; The titanium metal stripping solution is prepared by the following steps: Deionized water was added to an acid-resistant container, followed by slow addition of hydrofluoric acid, followed by uniform stirring at 150 r / min, followed by addition of hydrochloric acid and concentrated sulfuric acid, followed by continued stirring and cooling to 5°C, followed by addition of hydrogen peroxide, and finally by addition of a corrosion inhibitor to prepare a titanium metal stripping solution.

[0024] The mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

[0025] The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 65°C while stirring, keep warm and react for 1 hour, add dropwise a 50% sodium hydroxide aqueous solution, continue to heat to 80°C, and reflux for 6 hours. After the reaction, separate the oil layer first, extract the water layer with toluene, combine the organic phases, wash with deionized water until neutral, dry at 60°C, and rotary evaporate to obtain a corrosion inhibitor. The amount ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.02 mol: 0.02 mol: 0.25 g: 20 mL: 30 mL.

[0026] Example 2: A titanium metal stripping solution based on a composite acid system, characterized in that it comprises the following raw materials in parts by weight: 12 parts of hydrofluoric acid, 4 parts of hydrochloric acid, 1.2 parts of sulfuric acid, 1.1 parts of hydrogen peroxide, 3 parts of corrosion inhibitor, and 82 parts of deionized water; The titanium metal stripping solution is prepared by the following steps: Deionized water was added to an acid-resistant container, followed by slow addition of hydrofluoric acid, followed by uniform stirring at 150 r / min, followed by addition of hydrochloric acid and concentrated sulfuric acid, followed by continued stirring and cooling to 5°C, followed by addition of hydrogen peroxide, and finally by addition of a corrosion inhibitor to prepare a titanium metal stripping solution.

[0027] The mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

[0028] The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 65°C while stirring, keep warm and react for 1 hour, add dropwise a 50% sodium hydroxide aqueous solution, continue to heat to 80°C, and reflux for 6 hours. After the reaction, separate the oil layer first, extract the water layer with toluene, combine the organic phases, wash with deionized water until neutral, dry at 60°C, and rotary evaporate to obtain a corrosion inhibitor. The dosage ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.03 mol: 0.03 mol: 0.28 g: 20 mL: 40 mL.

[0029] Example 3: A titanium metal stripping solution based on a composite acid system, characterized in that it comprises the following raw materials in parts by weight: 14 parts of hydrofluoric acid, 4 parts of hydrochloric acid, 1.4 parts of sulfuric acid, 1.2 parts of hydrogen peroxide, 4 parts of corrosion inhibitor, and 84 parts of deionized water; The titanium metal stripping solution is prepared by the following steps: Deionized water was added to an acid-resistant container, followed by slow addition of hydrofluoric acid, followed by uniform stirring at 200 r / min, followed by addition of hydrochloric acid and concentrated sulfuric acid, followed by continued stirring and cooling to 10°C, followed by addition of hydrogen peroxide, and finally by addition of a corrosion inhibitor to prepare a titanium metal stripping solution.

[0030] The mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

[0031] The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 70°C while stirring, keep warm and react for 1 hour, add dropwise a 50% sodium hydroxide aqueous solution, continue to heat to 80°C, and reflux for 8 hours. After the reaction, separate the oil layer first, extract the water layer with toluene, combine the organic phases, wash with deionized water until neutral, dry at 80°C, and rotary evaporate to obtain a corrosion inhibitor. The dosage ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.04 mol: 0.04 mol: 0.28 g: 20 mL: 40 mL.

[0032] Example 4: A titanium metal stripping solution based on a composite acid system, characterized in that it comprises the following raw materials in parts by weight: 15 parts of hydrofluoric acid, 5 parts of hydrochloric acid, 1.5 parts of sulfuric acid, 1.2 parts of hydrogen peroxide, 5 parts of corrosion inhibitor, and 85 parts of deionized water; The titanium metal stripping solution is prepared by the following steps: Deionized water was added to an acid-resistant container, followed by slow addition of hydrofluoric acid, followed by uniform stirring at 200 r / min, followed by addition of hydrochloric acid and concentrated sulfuric acid, followed by continued stirring and cooling to 10°C, followed by addition of hydrogen peroxide, and finally by addition of a corrosion inhibitor to prepare a titanium metal stripping solution.

[0033] The mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

[0034] The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 70°C while stirring, keep warm and react for 1 hour, add dropwise a 50% sodium hydroxide aqueous solution, continue to heat to 80°C, and reflux for 6-8 hours. After the reaction, separate the oil layer first, extract the water layer with toluene, combine the organic phases, wash with deionized water until neutral, dry at 60-80°C, and rotary evaporate to obtain a corrosion inhibitor. The dosage ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.05 mol: 0.05 mol: 0.3 g: 20 mL: 50 mL.

[0035] Comparative Example 1: This comparative example is a stripping solution produced by a certain company on the market.

[0036] The stripping effects of the stripping solutions prepared in Examples 1-4 and Comparative Example 1 were tested, and the results are shown in Table 1 below: Test method: Place the workpiece to be stripped into the stripping solution at room temperature, shake it so that the workpiece is completely exposed to the stripping solution, and observe how long it takes for the workpiece to completely change color.

[0037] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Time min 3-4 3-5 3-4 3-4 12-18 It can be seen from Table 1 above that the stripping solutions prepared in Examples 1-4 of the present invention have high-efficiency stripping performance.

[0038] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A titanium metal stripping solution based on a composite acid system, characterized in that: The method comprises the following raw materials in parts by weight: 10-15 parts of hydrofluoric acid, 3-5 parts of hydrochloric acid, 1-1.5 parts of sulfuric acid, 1-1.2 parts of hydrogen peroxide, 2-5 parts of corrosion inhibitor, and 80-85 parts of deionized water; The corrosion inhibitor is prepared by the following steps: Add benzotriazole and n-dodecane bromide to toluene, stir evenly, then add tetrabutylammonium bromide, transfer to a three-necked flask, heat to 65-70°C while stirring, keep warm and react for 1 hour, add sodium hydroxide aqueous solution dropwise after the reaction, continue to heat to 80°C, reflux reaction for 6-8 hours, and perform post-treatment after the reaction to obtain a corrosion inhibitor.

2. The titanium metal stripping solution based on a composite acid system according to claim 1, characterized in that: The dosage ratio of benzotriazole, n-dodecane bromide, tetrabutylammonium bromide, sodium hydroxide aqueous solution and toluene is controlled to be 0.02-0.05 mol: 0.02-0.05 mol: 0.25-0.3 g: 20 mL: 30-50 mL.

3. The titanium metal stripping solution based on a composite acid system according to claim 1, characterized in that: The mass fraction of the sodium hydroxide aqueous solution is 50%.

4. The titanium metal stripping solution based on a composite acid system according to claim 1, characterized in that: The specific steps of the post-treatment are: firstly separating the oil layer, extracting the water layer with toluene, combining the organic phases, washing with deionized water until neutral, drying, and rotary evaporation.

5. The titanium metal stripping solution based on a composite acid system according to claim 4, characterized in that: The drying temperature is 60-80°C.

6. The titanium metal stripping solution based on a composite acid system according to claim 1, characterized in that: The mass fraction of the hydrofluoric acid is 40%, the mass fraction of the hydrochloric acid is 36%, the mass fraction of the sulfuric acid is 98%, and the mass fraction of the hydrogen peroxide is 30%.

7. The titanium metal stripping solution based on a composite acid system according to claim 1, characterized in that: The titanium metal stripping solution is prepared by the following steps: Add deionized water to an acid-resistant container, then slowly add hydrofluoric acid, stir uniformly at a speed of 150-200 r / min, add hydrochloric acid and concentrated sulfuric acid, continue stirring and cool to 5-10°C, add hydrogen peroxide, and finally add corrosion inhibitor to prepare a titanium metal stripping solution.

8. A titanium metal stripping solution based on a composite acid system according to any one of claims 1 to 6, characterized in that: The stripping solution is used for titanium alloy surface treatment.