KR102040978B1 - Surface treatment method of aluminum metallic materials - Google Patents

Abstract

The present invention relates to a method for treating a surface of an aluminum-based metal material and an aluminum-based metal material prepared according to the present invention. An alkali treatment step, a passivation step of dipping and drying the alkali treated metal material in an acidic solution, and conditioning the immobilized metal material in a low concentration aqueous solution of hydrogen peroxide, followed by washing in a high concentration aqueous solution of hydrogen peroxide (conditioning) step.

Description

Surface treatment method of aluminum-based metal material {SURFACE TREATMENT METHOD OF ALUMINUM METALLIC MATERIALS}

TECHNICAL FIELD This invention relates to the surface treatment method of an aluminum type metal material, and the aluminum type metal material manufactured by this.

The propulsion thruster for positioning and attitude control of satellites is a technology that has a strong ripple effect that can be applied to satellites, projectiles, and missiles in common. For this reason, technology transfer from the spacecraft is almost impossible, and it is an area that requires further development efforts in the future.

Compared to other types of thrusters such as electric thrusters or gelpropellant thrusters, chemical thrusters have been used steadily since the early days of space development, and are highly commercially available at a relatively low cost as well as high reliability. In addition, various models are already being traded in the space market.

In Korea, through the development of KOMPSAT, the 5N-class low-orbit satellite single thruster using hydrazine has been successfully localized and commercialized. The projectile and aircraft thruster system are mainly toxic hydrazine thruster systems. Has been utilized. However, the leading research groups in the world are aware of the environmental and technical costs incurred by toxic propellants and are conducting research on green propellants.

Green propellant, a single propellant developed to replace hydrazine, includes hydrogen peroxide, HAN series, and ADN series. In particular, since the 1950s, the development of a single propulsion system using hydrogen peroxide has been poorly supported due to lower non-thrust than other single propellants. However, recently, research on the development of 100 kg small satellites has been carried out due to the eco-friendly nature of hydrogen peroxide. have. Hydrogen peroxide used as propellant has a high concentration of 93wt% or more and is superior to hydrazine, which is a single propellant in density and freezing point.

However, since hydrogen peroxide is easily decomposed by catalysis at room temperature, it does not require preheating of the catalyst for propellant decomposition and is environmentally friendly because it generates only oxygen, water vapor and energy as the decomposition reaction takes place, and the material itself is higher than hydrazine. Has the advantage of low toxicity, but has the property of self-decomposing at room temperature. When hydrogen peroxide is decomposed, oxygen is produced, which is why i) the thruster system is made of a material that is not suitable for hydrogen peroxide, ii) hydrogen peroxide is stored in an incompatible vessel, or iii) hydrogen peroxide is contaminated by catalyst or impurities. The reaction occurs rapidly, releasing a large amount of heat and gas, and there is a high risk of system destruction, fire and explosion.

Therefore, there is an urgent need for the development of a technology that can improve the chemical compatibility between various materials and high concentrations of hydrogen peroxide that are used or planned to be used in the manufacture of thruster systems. In particular, the development of an effective surface treatment technology in which aluminum alloys, which are widely used for the storage of high concentration hydrogen peroxide and the manufacture of thrusters, do not undermine the storage stability of hydrogen peroxide and at the same time do not significantly damage the surface structure of the alloy by the oxidation of hydrogen peroxide. This is necessary.

However, since the thruster system using the eco-friendly propellant in Korea is in the beginning stage, research and development of surface treatment method for improving the suitability of aluminum material for long-term storage of high concentration hydrogen peroxide propellant has not been active.

The present invention is to solve the above problems, the cleaning step of washing the surface of the metal material including aluminum, the alkali treatment step of treating the surface of the washed metal material with an alkali solution, the alkali-treated acidic metal material A passivation step of immersing and drying the solution and conditioning the passivated metal material in a low concentration aqueous solution of hydrogen peroxide, followed by conditioning in a high concentration aqueous solution of hydrogen peroxide. It is to provide a surface treatment method.

More specifically, the method for treating the surface of the aluminum-based metal material may provide an aluminum-based metal material in which the pressure rise is suppressed to effectively suppress the decomposition of hydrogen peroxide and, as time passes, the decomposition rate of the hydrogen peroxide is lowered.

However, the problem to be solved by the present invention is not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

In accordance with an embodiment of the present invention, a method for treating a surface of an aluminum-based metal material includes: a washing step of washing a surface of a metal material including aluminum, an alkali treatment step of treating an surface of the washed metal material with an alkali liquid, and an alkali treatment A passivation step of immersing the dried metal material in an acidic solution and drying, and conditioning the passivated metal material in a low concentration aqueous solution of hydrogen peroxide, followed by conditioning in a high concentration solution of hydrogen peroxide. do.

According to one embodiment of the invention, the aluminum-based metal material after the conditioning step, the ratio of the oxygen atoms and aluminum atoms (O / Al ratio) of the surface may be 1.2 to 1.49.

According to one embodiment of the present invention, the ratio of oxygen atoms to aluminum atoms (O / Al ratio) of the surface may be reduced from 0.01 to 0.08 per 1 nm depth, up to 5 nm depth from the surface of the aluminum-based metal material have.

According to one embodiment of the invention, the washing step, the first washing step to remove foreign substances on the surface of the metal material using a neutral detergent, the second washing step to wash using water (H ₂ O), de The method may include a third washing step of removing ions from the surface using ionized water (DIW) and a drying step of drying the metal material.

According to one embodiment of the present invention, the first washing step may be to rub the surface of the metal material.

According to one embodiment of the invention, the alkaline liquid may be one or more selected from the group consisting of sodium ions, potassium ions and ammonium ions.

According to one embodiment of the present invention, the alkali treatment step may be performed for 1 minute to 20 minutes at a temperature of 10 ℃ to 30 ℃.

According to one embodiment of the present invention, the number of grams (g) of the solute containing at least one selected from the group consisting of sodium ions, potassium ions and ammonium ions dissolved in 100 g of the alkaline solution is 0.01 to 0.50 It may be.

According to one embodiment of the present invention, the alkali treatment step may further include an additional washing step of washing using water or deionized water.

According to one embodiment of the invention, the passivation (passivation) step, may be to immerse the metal material for 1 minute to 120 minutes in an acidic solution at a temperature of 25 ℃ to 75 ℃.

According to one embodiment of the invention, the acidic solution may be one or more selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid.

According to one embodiment of the present invention, the number of grams (g) of the solute containing one or more selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid dissolved in 100 g of the acidic solution may be 40 to 50.

According to one embodiment of the present invention, the passivation step may further include a further washing step of washing using water or deionized water.

According to an embodiment of the present invention, the concentration of the high concentration of hydrogen peroxide aqueous solution may be two to three times the concentration of the low concentration hydrogen peroxide solution.

According to an embodiment of the present invention, the capacity of the high concentration hydrogen peroxide solution in the washing step using the high concentration hydrogen peroxide aqueous solution, the concentration of the low concentration hydrogen peroxide aqueous solution in the step of conditioning in a low concentration hydrogen peroxide aqueous solution will be 1/20 to 1/5 Can be.

According to another embodiment of the present invention, an aluminum-based metal material having stability against hydrogen peroxide includes an aluminum-based metal material surface-treated according to the above-described embodiment, wherein the aluminum-based metal material, It includes that the ratio of oxygen atoms and aluminum atoms (O / Al ratio) to the depth of 100 nm from the surface is 1.2 to 1.49.

According to one embodiment of the present invention, the aluminum-based metal material, the surface-treated according to one embodiment described above, the ratio of the oxygen atoms and aluminum atoms (O / Al ratio) of the surface is 1.2 to 1.49 It may be.

According to an embodiment of the present invention, the aluminum-based metal material may be one in which the ratio of O / Al ratios of oxygen atoms and aluminum atoms on the surface per 1 nm depth is reduced from 0.01 to 0.08 to 5 nm deep from the surface. have.

The present invention provides a cleaning step of washing the surface of a metal material including aluminum, an alkali treatment step of treating the surface of the washed metal material with an alkali solution, and a passivation method for immersing and drying the alkali-treated metal material in an acidic solution ( It is possible to provide a method for surface treatment of an aluminum-based metal material including a conditioning step in which a passivation step and the passivated metal material are conditioned in a low concentration aqueous solution of hydrogen peroxide and then washed in a high concentration aqueous solution of hydrogen peroxide. .

More specifically, it is possible to provide an aluminum-based metal material which is excellent in storage stability and material suitability of hydrogen peroxide, so that hydrogen peroxide is slowly decomposed and low in active oxygen loss rate (AOL).

1 is a process chart of a surface treatment method of an aluminum-based metal material according to an embodiment of the present invention.
Figure 2 shows the measurement results of the active oxygen loss rate (Active Oxygen Loss, AOL) according to the surface treatment conditions of the aluminum alloy specimen prepared according to an embodiment of the present invention.
3 is a result of measuring the ratio of oxygen atoms and aluminum atoms (O / Al ratio) to the depth of 100 nm from the surface of the aluminum-based metal material prepared according to an embodiment of the present invention.
FIG. 4 shows the relationship between the active oxygen loss rate (AOL) measured in FIGS. 2 and 3 and the ratio of oxygen atoms and aluminum atoms (O / Al ratio) to the depth of 100 nm from the surface of the aluminum-based metal material. Table shown.
5 is a result of measuring the amount of reduction in the ratio (O / Al ratio) of oxygen atoms and aluminum atoms per 1 nm from the surface of the aluminum-based metal material prepared according to an embodiment of the present invention to 5 nm depth.
6 is a result of observing the pressure increase after the surface treatment of the hemispherical tank using the surface treatment method of the aluminum-based metal material according to an embodiment of the present invention.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. However, various changes may be made to the embodiments so that the scope of the patent application is not limited or limited by these embodiments. It is to be understood that all changes, equivalents, and substitutes for the embodiments are included in the scope of rights.

The terminology used herein is for the purpose of description and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprise" or "have" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

In addition, in the description with reference to the accompanying drawings, the same components regardless of reference numerals will be given the same reference numerals and duplicate description thereof will be omitted. In the following description of the embodiment, when it is determined that the detailed description of the related known technology may unnecessarily obscure the gist of the embodiment, the detailed description thereof will be omitted.

When an element or layer is represented as "on", "connected to" or "coupled to" another element or layer, this is directly another element or layer. It may be understood that the layers may be present, connected or combined, or there may be intervening elements and layers.

Hereinafter, a method of surface treatment of an aluminum-based metal material of the present invention and an aluminum-based metal material having stability with respect to hydrogenated peroxide according to the present invention will be described in detail with reference to Examples and drawings. However, the present invention is not limited to these embodiments and drawings.

In accordance with an embodiment of the present invention, a method for treating a surface of an aluminum-based metal material includes: a washing step of washing a surface of a metal material including aluminum, an alkali treatment step of treating an surface of the washed metal material with an alkali liquid, and an alkali treatment A passivation step of immersing the dried metal material in an acidic solution and drying, and conditioning the passivated metal material in a low concentration aqueous solution of hydrogen peroxide, followed by conditioning in a high concentration solution of hydrogen peroxide. do.

According to one side, the aluminum-based metal material may be used in fuel storage tanks, such as automotive, aviation, military, etc., preferably a material suitable for the propellant storage tank of the aircraft thruster system.

According to one side, the aluminum-based metal material is not particularly limited as long as it can be a high-strength aluminum liner secured stability and economical efficiency, can be molded into a cylindrical shape, the ultra-high pressure gas acting on the storage tank on its outer surface It may be made of a composite material to ensure sufficient strength safety even under pressure.

According to one side, the aluminum liner is not particularly limited as long as the winding of the high strength yarn and filament yarn is easy.

According to one side, the metal material including aluminum, may include a composite material such as aluminum, aluminum alloy or aluminum and carbon fiber, preferably may be an aluminum alloy.

According to one embodiment of the invention, the washing step, the first washing step to remove foreign substances on the surface of the metal material using a neutral detergent, the second washing step to wash using water (H ₂ O), de The method may include a third washing step of removing ions from the surface using ionized water (DIW) and a drying step of drying the metal material.

According to one side, the first washing step may be to use a neutral detergent to remove foreign substances or grease on the surface of the metal material including aluminum.

According to one side, the first washing step may be to wash for at least 1 minute.

According to one side, the neutral detergent is not particularly limited as long as it is a neutral detergent that is not acidic or alkaline, and may include, for example, a general kitchen detergent.

According to one side, when washing with an acidic or alkaline detergent, rather than a neutral detergent in the first washing step, there may be corrosion or discoloration of the metal surface.

According to one side, the secondary washing step may be to wash using water (H ₂ O), for example, tap water, and through the secondary washing step, the greasy combined with the Michelle structure of the neutral detergent on the surface Alternatively, the step may be a step in which foreign matters are lightly washed.

According to one side, the third washing step may be a step of removing all residual ions remaining on the surface of the metal material using deionized water (DIW).

According to one side, the secondary and tertiary washing step, by using tap water and deionized water, respectively, the object to be removed or washed is different, the degree of contamination of the surface of the metal material according to such a step washing It can be minimized.

According to one side, the washing step is a preliminary step for alkali treatment of the metal material in which both the neutral detergent and the foreign substances have been washed through the third washing step, to completely remove the foreign substances on the surface of the metal material to ensure quality. It may be preferably dried at 50 to 70 ℃ 1 hour to 5 hours, more preferably at 60 ℃ 3 hours.

According to one embodiment of the present invention, the first washing step may be to rub the surface of the metal material.

According to one side, the rubbing (rubbing) means to clean by hand rubbing, without using an object that can affect the surface of the metal material, which minimizes the friction of the surface of the metal material to preserve quality For sake.

According to one embodiment of the invention, the alkaline liquid may be one or more selected from the group consisting of sodium ions, potassium ions and ammonium ions.

According to one side, the alkaline liquid of the alkali treatment step can effectively remove the oil (oil) component on the surface of the aluminum-based metal material.

According to one side, the alkaline liquid may remove the lubricant on the surface of the aluminum-based metal material.

According to one side, in the alkali treatment step, the surface of the aluminum metal material generated by treating the alkaline liquid may be etched in small amounts, and the etching amount may be less than 50 mg / m ² , that is, the alkaline liquid May hardly etch the surface of the aluminum metal material.

According to one side, when the etching amount in the alkali treatment step is 50 mg / m ^{2 or} more, the surface of the aluminum metal material may be whitened.

According to one side, the etching amount of the metal material surface is a method of precisely measuring the mass of the metal material before and after the alkali treatment step, and dividing the amount of reduction of the mass of the metal material before and after the alkali treatment step by the surface area of the metal material. It can be measured.

According to one side, the alkali liquid may preferably have a pH of 9 to 14, most preferably 10 to 13, by using an alkali liquid in the above range, to form a film of hydroxide on the surface of the metal material Can be.

According to one side, the hydroxide film on the surface of the metal material can be dissolved by the acidic solution in the passivation step, the pH is 10 in order to efficiently form the film of the hydroxide in the alkali treatment step and at the same time to suppress the etching amount To 13;

According to one side, by containing one or more ions selected from the group consisting of the sodium ions, potassium ions and ammonium ions, it is possible to effectively form a film on the surface of the aluminum-based metal material.

According to one side, as the source of the sodium ions, potassium ions and ammonium ions, minerals such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, ammonium bicarbonate, or sodium salts of organic acids such as gluconic acid or citric acid It may be an organic substance of, potassium salt, ammonium salt, these compounds may be used in combination of two or more kinds.

According to one side, the alkaline liquid, preferably, may be an aqueous solution containing sodium hydroxide, by using a highly alkaline aqueous sodium hydroxide solution as an alkaline liquid, the coating of the hydroxide on the surface of the aluminum-based metal material more effectively Can be formed.

According to one side, the alkaline liquid may further include at least one selected from the group consisting of an organic acid, a chelating agent, a dispersing agent and a surfactant.

According to one side, when the alkaline liquid further contains an organic acid, a chelating agent, a dispersing agent or a surfactant, even if the alkali treatment step is performed at a low temperature and within a short time, the smut of the surface of the aluminum-based metal material can be efficiently It can be removed to promote the film formation of the hydroxide.

According to one side, the organic acid may include an alkali metal salt such as gluconic acid, citric acid, oxalic acid, malic acid, tartaric acid, sorbic acid, succinic acid and sodium or potassium salt thereof.

According to one side, the chelating agent may be an aminocarboxylic acid chelating agent, phosphonic acid chelating agent, condensed phosphate. Specifically, it may include ethylenediamine tetraacetic acid (EDTA), 1-hydroxyethylidene-1, 1-diphosphonate (HEDP), nitrilotriacetic acid (NTA), sodium tripolyphosphate (STPP).

According to one side, the dispersant may include a maleic acid acrylic acid copolymer, its sodium salt, polycarboxylic acid, polyethylene glycol.

According to one side, the surfactant may include a nonionic, cationic, anionic, amphoteric surfactant, preferably, may be a nonionic, for example, hydrocarbon derivatives, Abietic acid derivatives, alcohol ethoxylates, modified polyethoxylated alcohols can be used.

According to one embodiment of the present invention, the alkali treatment step may be performed for 1 minute to 20 minutes at a temperature of 10 ℃ to 30 ℃.

According to one side, when performing the alkali treatment step under the above conditions, it is possible to effectively form a film on the surface of the aluminum-based metal material, while maintaining a very small amount of etching.

According to one side, the alkali treatment step may be performed once, or may be performed multiple times.

According to one side, when the alkali treatment step is performed a plurality of times, the treatment conditions may be the same or changed in each treatment process.

According to one embodiment of the present invention, the number of grams (g) of the solute containing at least one selected from the group consisting of sodium ions, potassium ions and ammonium ions dissolved in 100 g of the alkaline solution is 0.01 to 0.50 It may be.

According to one side, the concentration of the alkaline liquid, the number of grams (g) of the solute dissolved in 100 g of the alkaline solution, 0.01 to 0.50, may be 0.01 wt% to 0.50 wt%.

According to one side, when the concentration of the alkali liquid is lower than 0.01 wt%, it may be difficult to form a hydroxide coating on the surface of the aluminum-based metal material, and when higher than 0.50 wt%, the surface of the aluminum-based metal material is excessively etched to whiten Can be.

According to one embodiment of the present invention, the alkali treatment step may further include an additional washing step of washing using water or deionized water.

According to one side, the additional washing step, after the first wash using water (tap water) to remove the aqueous solution of sodium hydroxide on the surface of the metal material, the alkali ions on the surface using deionized water (DIW) The second wash to remove may be a stepwise wash.

According to one embodiment of the invention, the passivation (passivation) step, may be to immerse the metal material for 1 minute to 120 minutes in an acidic solution at a temperature of 25 ℃ to 75 ℃.

According to one side, the passivation step is a process of forming an oxide film on the metal surface to resist corrosion, for example, when passivating a component made of stainless steel, iron is removed from the surface. Removing, but leaving other components such as alloys such as chromium and nickel, may mean a process that promotes the formation of oxides that protect against corrosion.

According to one side, the passivated aluminum-based metal material may have the effect of improved corrosion resistance, uniform and smooth appearance, deburred surface, cleanliness and product life.

According to one side, the metal material for passivation treatment may be neutralized, but not dried, after the alkali treatment step, and may have only a film of hydroxide formed without passivation in the above-described alkali treatment step.

According to one side, since the film of hydroxide is easily dissolved by an acidic solution, it is possible to etch the surface of the aluminum-based metal material by the acidic solution in the passivation step.

According to one side, the passivation step under the above conditions may be a range that does not excessively etch while sufficiently forming an oxide film on the surface of the metal material.

According to one side, if the treatment temperature (acid solution immersion temperature) of the aluminum-based metal material in the passivation step is higher than 75 ° C., the energy cost in the surface treatment of the metal material may be too high, which may not be desirable.

According to one side, the passivating step is to immerse in an acidic solution for 1 to 120 minutes, preferably can be immersed for 1 hour, if less than 1 hour immersion time, there is not enough corrosion does not occur oxidation It can be difficult to form a coating.

According to one embodiment of the invention, the acidic solution may be one or more selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid.

According to one side, the acidic solution may be pH 2 or more, if greater than 2, passivation may not occur sufficiently.

According to one side, the acidic solution may include an inorganic acid, the inorganic acid has the function of an etching accelerator, may include sulfuric acid, nitric acid, phosphoric acid, these inorganic acids may be used alone or in combination.

According to one embodiment of the present invention, the number of grams (g) of the solute containing one or more selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid dissolved in 100 g of the acidic solution may be 40 to 50.

According to one side, the concentration of the acidic solution, the number of grams (g) of the solute dissolved in 100 g of the acidic solution, 40 to 50, may be 40 wt% to 50 wt%.

According to one side, when the concentration of the acidic solution is lower than 40 wt%, the acidic coating may not be formed sufficiently, if higher than 50 wt%, the surface of the aluminum-based metal material may be excessively etched, thereby degrading the quality. Preferably 45 wt%.

According to one side, the acidic solution may further include a surfactant, and the surfactant may have a function of removing oils and lubricants remaining mainly on the surface of the aluminum-based metal material. It may also have a function of preventing the removed fat or oil component from floating during cleaning, and if the fat or oil component is suspended during cleaning, it may be resorbed on the surface of the aluminum-based metal material. .

According to one side, the surfactant may include a nonionic, cationic, anionic, zwitterionic, preferably nonionic, ethoxylated alkylphenols, hydrocarbon derivatives, abiet Acid derivatives, primary ethoxylated alcohols, modified polyethoxylated alcohols.

According to one embodiment of the present invention, the passivation step may further include an additional washing step of washing using water or deionized water.

According to one side, the additional washing step, after a sufficient washing for 10 minutes using water (tap water) to remove the acidic solution on the surface of the metal material, and then immersed in deionized water (DIW) for at least 5 minutes To remove all residual ions.

According to one side, after the further washing step, the metal material surface may be dried for at least 10 hours at a temperature of room temperature to 70 ℃.

According to one side, the conditioning step may include the step of conditioning the immobilized metal material in a low concentration aqueous solution of hydrogen peroxide for 24 to 48 hours and washing the metal material using a high concentration aqueous solution of hydrogen peroxide. .

According to one side, the conditioning may refer to conditioning of the oxide surface or scale at the metal surface.

According to one side, the conditioning may be immersed in a low concentration aqueous hydrogen peroxide solution for a long time.

According to one side, the low concentration hydrogen peroxide aqueous solution may be a temperature of 20 ℃ to 30 ℃.

According to one side, after conditioning for 24 hours to 48 hours in the low concentration aqueous hydrogen peroxide solution, the low concentration aqueous hydrogen peroxide solution can be removed.

According to one side, the metal material from which the low concentration aqueous hydrogen peroxide solution is removed may be washed using a high concentration aqueous hydrogen peroxide solution.

According to an embodiment of the present invention, the concentration of the high concentration of hydrogen peroxide aqueous solution may be two to three times the concentration of the low concentration hydrogen peroxide solution.

According to one side, the concentration of the low concentration hydrogen peroxide aqueous solution, the number of grams (g) of hydrogen peroxide dissolved in 100 g of hydrogen peroxide aqueous solution is 25 to 50, may be 25 wt% to 50 wt%, preferably 35 wt%.

According to one side, the concentration of the high concentration hydrogen peroxide aqueous solution, the number of grams (g) of hydrogen peroxide dissolved in 100 g of hydrogen peroxide aqueous solution is 50 to 99, may be 50 wt% to 99 wt%, preferably 90 wt%.

According to one side, by conditioning and washing with the high and low concentration of hydrogen peroxide solution, the aluminum-based metal material does not impair the storage stability of hydrogen peroxide, and at the same time the surface structure of the metal material is greatly increased by the oxidation of hydrogen peroxide It may not be damaged.

According to an embodiment of the present invention, the capacity of the high concentration hydrogen peroxide solution in the washing step using the high concentration hydrogen peroxide aqueous solution, the concentration of the low concentration hydrogen peroxide aqueous solution in the step of conditioning in a low concentration hydrogen peroxide aqueous solution will be 1/20 to 1/5 Can be.

According to one side, the capacity of the high concentration hydrogen peroxide aqueous solution may be 1/20 to 1/5, preferably 1/10 of the low concentration hydrogen peroxide aqueous solution in the step of conditioning in a low concentration hydrogen peroxide aqueous solution.

According to one side, the low concentration hydrogen peroxide aqueous solution may be used more than 30 mL, preferably 50 mL, high concentration hydrogen peroxide aqueous solution 3mL to 7mL, preferably 5mL may be used.

According to one side, the washing using the high concentration hydrogen peroxide aqueous solution may be to wash once or multiple times by 5mL.

According to another embodiment of the present invention, an aluminum-based metal material having stability against hydrogen peroxide includes an aluminum-based metal material surface-treated according to the above-described embodiment, wherein the aluminum-based metal material, It includes that the ratio of oxygen atoms and aluminum atoms (O / Al ratio) to the depth of 100 nm from the surface is 1.3 to 1.7.

According to one side, the aluminum element present on the surface of the aluminum-based metal material can form a variety of bonds with other atoms, in particular, depending on whether or not bonded to oxygen atoms, metal aluminum (Al), aluminum oxide (Al ₂ O ₃ ) and aluminum hydroxide (Al (OH) ₃ or AlOOH) can be divided into three forms.

According to one side, the ratio of oxygen atoms to aluminum atoms (O / Al ratio) to the depth of 100 nm from the surface can be measured by using XPS and Ion gun, and as a result, aluminum is combined with oxygen in some form Can be analyzed.

According to one side, the aluminum-based metal material may have an O / Al ratio of 1.3 to 1.7, preferably close to 1.5, which may be present in the form of aluminum oxide.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

However, the following examples are only for illustrating the present invention, and the contents of the present invention are not limited to the following examples.

Examples 1-3. Surface treatment method of aluminum-based metal material

Psalms

Four specimens of Al2024, Al5052, Al6061, and Al7075 aluminum alloys of 1 cm × 1 cm × 1 cm size were used.

2. Surface treatment method

(1) detergent cleaning

In order to remove foreign substances or grease on the surface of the aluminum alloy specimen was washed for 1 minute using a neutral detergent. In the process of using detergent, it was based on washing by hand without using any materials that could affect the surface of the specimen such as loofah. After washing with detergent, a first wash was performed using tap water, and ions remaining in the specimen were removed using deionized water. After washing the detergent, the specimen was dried for 3 hours at 60 ℃.

(2) alkali treatment

After the detergent wash, the dried specimen was placed in 50 mL of 0.25 wt% aqueous sodium hydroxide solution maintained at 20 ° C. ± 10 ° C., and soaked for 10 minutes. Thereafter, an aqueous sodium hydroxide solution was removed, and a first wash was performed using tap water, and then deionized water was used to remove ions remaining in the specimen.

(3) Passivation treatment

After sodium hydroxide treatment, completely neutralized specimens were placed in 50 mL of 45 wt% aqueous nitric acid solution at 25 ° C. (Example 1), 50 ° C. (Example 2) and 75 ° C. (Example 3) , respectively, without drying. While immersed. After carefully removing the 45 wt% aqueous nitric acid solution, the flask containing the specimen was washed sufficiently with tap water for 10-15 minutes, 50 mL of deionized water was added and kept at room temperature for 5 minutes to remove ions due to tap water. The washing deionized water was then carefully discarded and the flask containing the specimen was placed in a forced convection oven and dried at 65 ° C. for 12 hours.

(4) Conditioning treatment

After nitric acid passivation, 50 mL of 35 wt% aqueous hydrogen peroxide solution was added to a flask containing dried specimens, and maintained at room temperature for 36 hours. Thereafter, the aqueous solution of 35 wt% hydrogen peroxide was carefully discarded, and the specimen was washed with 5 mL of 90 wt% of high concentration of hydrogen peroxide.

Since the refractive index of the aqueous hydrogen peroxide solution increased in proportion to the concentration of hydrogen peroxide, the concentration of the hydrogen peroxide was measured using an ATAGO company's Refractometer, which calculates the concentration from the refractive index of the aqueous hydrogen peroxide solution using this property.

Comparative Example 1.

Of the surface treatment method of Examples 1 to 3, only the Rinsing step by washing the detergent was performed.

Comparative Example 2.

In the surface treatment method of Examples 1 to 3, only the Rinsing step and the alkali treatment step by detergent washing were performed.

Experimental Example 1.

One complete sample was placed in an Erlenmeyer flask, and 50 mL of 90 wt% hydrogen peroxide was added to observe the reaction for 2 hours or more. The reaction was visually observed while maintaining at room temperature for 2 weeks, and finally the weight loss of hydrogen peroxide was measured at 14 days.

Experimental Example 2. Calculation of Active Oxygen Loss (AOL)

Since water (H ₂ O) in the decomposition product of hydrogen peroxide is difficult to escape into the gas due to the heat of vaporization is large, it remains in the solution most after the decomposition reaction. On the other hand, since the oxygen (O ₂ ) gas is easily released from the solution, it is possible to determine the degree of decomposition reaction by measuring the weight change of hydrogen peroxide.

Active Oxygen Loss (AOL) represents the decomposition characteristics of hydrogen peroxide and is widely used as a quantitative index comparing the storage stability of hydrogen peroxide and the material suitability for hydrogen peroxide. The better the storage stability and material suitability of hydrogen peroxide, the slower hydrogen peroxide decomposes, resulting in a smaller AOL value.

The AOL value can be calculated from the change in weight and concentration of hydrogen peroxide using the following formula.

<Expression>

Wherein W1 and W2 are the oxygen peroxide weights before and after storage, respectively, and C1 and C2 are the carbon peroxide concentrations before and after storage. The higher the chemical compatibility of the specimen with hydrogen peroxide, the slower the decomposition of hydrogen peroxide, resulting in lower AOL.

Experimental Example 3. XPS analysis (O / Al ratio measurement)

The chemical composition was analyzed by measuring the XPS of the specimen surface using a PHI Quantera II model. X-rays used conditions of 100 um, 25 W and 15 kV. In addition, by using the ion gun sputtering to a depth of 100 nm from the surface was also measured by the composition by depth. The sputtering yield was 0.8 dl / s.

Since there is little change of O / Al ratio after 60 nm, in FIG. 3, it displays to 60 nm.

Experimental Example 4. Tank model experiment

In order to more accurately verify the effect of the surface treatment method developed in the present invention, four hemispherical tanks of about 20 L capacity were made of Al5052 material, and each tank was surface-treated in a different manner and filled with hydrogen peroxide, followed by about 24 During the time, the pressure of the gas (oxygen) generated by decomposition of hydrogen peroxide was measured.

The first tank (A) was prepared in the detergent washing step, alkali treatment step, passivation step and conditioning at 50 ° C as in the present invention.

The second tank (B) was only detergent cleaning.

The third tank (C) was surface treated by the Anodizing method, which is known to be effective in forming an oxide film.

The fourth tank (D) was coated inside the tank using a Teflon solution known to be very stable against hydrogen peroxide.

2 is a measurement result of AOL (%) according to Experimental Example 2 of the aluminum alloy specimens according to Examples 1 to 3 and Comparative Examples 1 and 2. Referring to FIG. 2, the passivation specimen at 50 ° C. showed the lowest AOL (%), resulting in the lowest decomposition rate of hydrogen peroxide. That is, when the passivation treatment temperature is more than 25 ℃ less than 70 ℃, more specifically 40 ℃ to 60 ℃, it was found that the chemical compatibility is excellent.

3 is a graph showing the change of O / Al ratio with the depth of the specimen, Figure 4 is a result of comparing the O / Al ratio and AOL (%) on the surface of the specimen (depth 0 nm). 5 is a result of calculating the amount of decrease in O / Al ratio per 1 nm depth from the specimen surface (0 nm depth) to 5 nm depth.

In general, the aluminum included in the specimen may be present in three states: metal aluminum (Al), aluminum oxide (Al ₂ O ₃ ), aluminum hydroxide (Al (OH) ₃ or AlOOH). Among the three states of aluminum, aluminum oxide is known to exhibit high stability against high concentration of hydrogen peroxide. Therefore, in order to increase the resistance to high concentration of hydrogen peroxide, it is important to form a thick and uniform aluminum oxide layer on the surface of the specimen.

The state of aluminum in the specimen can be determined by measuring the O / Al ratio. If the aluminum of the specimen is in the form of metal, the O / Al ratio is 0. If the aluminum of the specimen is in the state of aluminum oxide, the O / Al ratio is close to 1.5. In addition, in the state of aluminum hydroxide may exhibit an O / Al ratio of 2 to 3.

Referring to FIG. 3, it can be seen that the specimens treated with passivation at 50 ° C. (Example 2) were closer to 1.5 than the O / Al ratios present on the surface of the specimens than the specimens treated at other temperatures (Comparative Example). have. It can also be seen that the smallest decrease in O / Al ratio with depth is near the specimen surface (depth 0 to about 5 nm). This result means that in the embodiment according to the present invention, the aluminum oxide layer having excellent chemical suitability and stability is best formed.

4 and 5 further support the results of FIG. 3. Specifically, referring to FIG. 4, the specimens of the passivation example at 50 ° C. have an O / Al ratio of 1.28 to 1.475 on the surface, and it can be seen that most aluminum on the surface is in the state of aluminum oxide. . In addition, the specimens of the example exhibited the lowest AOL (%) value, it can be seen that more effectively inhibit the hydrogen peroxide decomposition than the comparative example.

In addition, referring to Figure 5, it can be seen that the specimens of the embodiment has a very small decrease in O / Al ratio per 1 nm to about 5 nm depth from the surface of about 0.05 ~ 0.07. On the other hand, in the comparative example, the O / Al ratio per 1 nm depth was greatly reduced to about 0.1 ~ 0.4. The result of FIG. 5 means that the aluminum oxide layer having excellent stability is formed thickest near the surface in the embodiment.

6 is the result of the tank model experiment of Experimental Example 4, the least pressure increase was observed in the tank surface-treated according to the present invention. In particular, it was confirmed that not only the Teflon-coated tank more effectively suppresses the decomposition of hydrogen peroxide, but also the decomposition rate (pressure rise rate) of the hydrogen peroxide decreases with time.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is represented by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present invention.

Claims (17)

A cleaning step of cleaning the surface of the metal material including aluminum;
An alkali treatment step of forming a hydroxide film on the surface of the washed metal material by using an alkali liquid;
A passivation step of dipping and drying the alkali treated metal material in an acidic solution; And
Conditioning the immobilized metal material in a low concentration aqueous hydrogen peroxide solution of at least 25 wt% and less than 50 wt%, followed by washing in a high concentration aqueous hydrogen peroxide solution of at least 50 wt% and 99 wt% or less;
Including,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The aluminum-based metal material after the conditioning step,
O / Al ratio of oxygen atoms and aluminum atoms on the surface is 1.2 to 1.49,
Surface treatment method of aluminum-based metal material. The method of claim 2,
The ratio (O / Al ratio) of oxygen atoms and aluminum atoms on the surface is
0.01 to 0.08 per 1 nm depth, down to 5 nm depth from the surface of the aluminum-based metal material,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The washing step,
A first washing step of removing foreign matter on the surface of the metal material using a neutral detergent;
A second washing step using water (H ₂ O);
A third washing step of removing ions from the surface using deionized water (DIW); And
A drying step of drying the metal material;
To include,
Surface treatment method of aluminum-based metal material. The method of claim 4, wherein
The first washing step,
To rub the surface of the metal material,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The alkaline liquid,
It comprises at least one selected from the group consisting of sodium ions, potassium ions and ammonium ions,
Surface treatment method of aluminum-based metal material. The method of claim 1.
The alkali treatment step is to be performed for 1 to 20 minutes at a temperature of 10 ℃ to 30 ℃,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The number of grams (g) of solute containing at least one selected from the group consisting of sodium ions, potassium ions and ammonium ions dissolved in 100 g of the alkaline liquid solution,
0.01 to 0.50,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The alkali treatment step,
Further comprising a further washing step of washing with water or deionized water,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The passivation step,
To immerse the metal material for 1 to 120 minutes in an acidic solution at a temperature of 25 ℃ to 75 ℃,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The acidic solution,
One or more selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The number of grams (g) of solute containing at least one selected from the group consisting of sulfuric acid, nitric acid and phosphoric acid dissolved in 100 g of the acidic solution,
40 to 50,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The passivation step,
Further comprising a further washing step of washing with water or deionized water,
Surface treatment method of aluminum-based metal material. The method of claim 1,
The concentration of the high concentration of hydrogen peroxide aqueous solution,
2 to 3 times the concentration of the low concentration hydrogen peroxide solution,
Surface treatment method of aluminum-based metal material. The method of claim 14,
The capacity of the high concentration hydrogen peroxide aqueous solution in the washing step using the high concentration hydrogen peroxide solution,
It is 1/20 to 1/5 of the capacity of the low concentration hydrogen peroxide aqueous solution in the step of conditioning in a low concentration aqueous hydrogen peroxide solution,
Surface treatment method of aluminum-based metal material. An aluminum-based metal material surface-treated according to any one of claims 1 to 15,
The aluminum-based metal material,
O / Al ratio of oxygen atoms and aluminum atoms on the surface is 1.2 to 1.49,
An aluminum-based metal material having stability against hydrogen peroxide. The method of claim 16,
The aluminum-based metal material,
To 5 nm deep from the surface, the O / Al ratio of the surface oxygen atoms and aluminum atoms per 1 nm depth is reduced by 0.01 to 0.08,
An aluminum-based metal material having stability against hydrogen peroxide.

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