KR102282622B1 - Coated magnesium powder and method of manufacturing the same - Google Patents

Abstract

The present invention provides a coated magnesium powder having excellent surface stabilization properties of the magnesium powder and a method for preparing the same. In the coated magnesium powder of the present invention, a coating including a carbon-containing material is stably formed on the surface of the magnesium powder. The method for producing a coated magnesium powder of the present invention comprises the steps of drying a magnesium dispersion prepared by adding magnesium powder to a mixture of a carbon source organic compound and a ketone-based solvent to form a coating with a carbon-containing source organic compound on the surface of the magnesium powder includes

Description

Coated magnesium powder and its manufacturing method {COATED MAGNESIUM POWDER AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to a coated magnesium powder and a method for preparing the same. Specifically, it relates to a coated magnesium powder having excellent surface stabilization properties of the magnesium powder and a method for manufacturing the same.

Metal powders with high reactivity are prone to corrosion, discoloration or oxidation. If you look at the reactivity of metals, potassium, sodium, lithium, strontium, and calcium are the most reactive in the order, and when exposed to the outside, they react violently with oxygen and water, so it is common to store them in a substance containing liquid hydrocarbons such as mineral oil.

On the other hand, the metals showing the highest reactivity after calcium are magnesium and aluminum. Magnesium does not ignite well in air, but its flammability increases in its fine powder form. In addition, it reacts with oxygen in the air to form a magnesium oxide film (MgO), which has low permeability and is difficult to remove, on the surface of the powder to prevent further oxidation. However, when an explosive oxidation reaction proceeds due to an external stimulus such as ignition, a bright white flame of 3100 ℃ is emitted and a large amount of energy is released. These properties have been used in camera flashes, fireworks, flash or incendiary bombs. The powder form, which is advantageous in terms of application of the explosive energy release as described above, must be taken care of in handling such as transport and assembly.

Conventionally, there have been attempts to improve handling ease by coating with carbon at the same time as manufacturing nanoscale magnesium powder using thermal plasma method, but due to the high reactivity of magnesium metal itself, magnesium oxide nanopowder and magnesium nanopowder are formed at the same time, The content of pure magnesium nanopowder was low.

In addition, carbon decomposed in methane gas is less reactive than magnesium and has very low mutual reactivity, so it is not coated on the outer surface of the magnesium nanopowder and exists separately from the magnesium nanopowder. It is simply a physical mixture of magnesium, magnesium oxide, and carbon. was found to be mixed with

An object of the present invention is to provide a coated magnesium powder having excellent surface stabilization properties of the magnesium powder and a method for economically manufacturing the coated magnesium powder through a simple process.

According to one aspect of the present invention, magnesium powder; and a coating disposed on the surface of the magnesium powder and comprising a carbon-containing material; There is provided a coated magnesium powder comprising a.

According to another aspect of the present invention, the method comprising the steps of: adding magnesium powder to a mixture of a carbon source organic compound and a ketone-based solvent to obtain a magnesium dispersion; and drying the magnesium dispersion to obtain a magnesium powder coated with a carbon source organic compound; There is provided a method for producing a coated magnesium powder comprising a.

In the coated magnesium powder according to an embodiment of the present invention, a coating including a carbon-containing material is stably formed on the surface of the magnesium powder, so it is easy to control the reaction itself from the outside while maintaining the high reactivity of the magnesium powder, It is easy to store and transport the powder, and it can be applied to various fields because it can improve thermal and electrical conductivity, and the low friction force of the coating including carbon-containing material protects the internal magnesium powder from external stimuli such as static electricity. can protect

In addition, the coated magnesium powder according to an embodiment of the present invention can prevent aggregation between the magnesium powder particles and prevent the magnesium powder particles from sintering and coarsening when processed at a high temperature.

The method for producing a coated magnesium powder according to another embodiment of the present invention can form a coating including a carbon-containing material on the surface of the magnesium powder by a simple process under mild conditions, and is stable even with a small amount of a carbon source organic compound. Carbon coatings can be formed, which can be economical and industrially mass-produced.

1 is a transmission electron microscope (TEM) picture of the coated magnesium powder of Examples 1 and 2.
2 is an EDS element mapping result of the coated magnesium powder of Examples 1 and 2.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

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

Coated magnesium powder according to an embodiment of the present invention, magnesium powder; and a coating disposed on the surface of the magnesium powder and comprising a carbon-containing material; includes

According to one embodiment of the present invention, the carbon-containing material may be at least one of a carbon atom, an organic acid, a hydrocarbon, and a carbohydrate. Specifically, the carbon-containing material may be at least one of organic acids, hydrocarbons and carbohydrates, or carbon atoms derived from at least one of organic acids, hydrocarbons and carbohydrates. More specifically, the carbon-containing material is contained in the form of one or more molecules of organic acids, hydrocarbons, and carbohydrates, in the form of organic acid anhydrides, or part or all of molecules of one or more of organic acids, hydrocarbons and carbohydrates are decomposed or reacted It may be included in the form of one or more of other types of organic acids, hydrocarbons and carbohydrates produced by That is, the carbon-containing material may be included as another type of material by decomposing or reacting at least one molecule of organic acids, hydrocarbons, and carbohydrates, or may be completely decomposed and included in the form of carbon atoms.

According to one embodiment of the present invention, the organic acid may include at least one of maleic acid, fumaric acid, succinic acid, malic acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid, and citric acid. For example, malic acid may be preferred.

According to an embodiment of the present invention, the carbon-containing material may be included in an amount of 1 mass% to 5 mass%, 1.1 mass% to 2.9 mass%, or 1.3 mass% to 2.5 mass% based on carbon atoms. Specifically, when the carbon-containing material is included in the coating in the form of one or more of organic acids, hydrocarbons and carbohydrates, the fraction of carbon atoms included is calculated through the molecular formula of one or more of organic acids, hydrocarbons and carbohydrates, and The mass ratio can be calculated. When the carbon-containing material is included in the content within the above range, the coating may be uniformly and stably formed on the outer surface of the magnesium powder, and the thickness of the coating may be appropriate by preventing the coating from becoming too thick, and the outer surface of the powder There is an effect of preventing the detachment of the carbon coating from That is, it is possible to prevent the carbon coating from being separated from the outer surface of the powder and being simply mixed with the magnesium powder.

According to one embodiment of the present invention, the thickness of the coating may be 0.1% to 10% of the diameter of the magnesium powder. When the coating thickness is within the above range, the carbon-coated magnesium powder can block the magnesium powder inside from the outside to reduce the risk of explosion while maintaining the reactivity of magnesium.

According to one embodiment of the present invention, the magnesium powder may have an average diameter of 0.05 μm to 50 μm.

A method for producing a coated magnesium powder according to another embodiment of the present invention includes the steps of adding magnesium powder to a mixture of a carbon source organic compound and a ketone-based solvent to obtain a magnesium dispersion; and drying the magnesium dispersion to obtain a magnesium powder coated with a carbon source organic compound; includes

The carbon source organic compound is a compound capable of forming a coating including a carbon-containing material, and may be one or more of an organic acid, a hydrocarbon, and a carbohydrate. Specific details of the carbon-containing material, the magnesium powder, and the carbon-containing material may be the same as those described above for the coated magnesium powder.

According to one embodiment of the present invention, magnesium powder is first added to a mixture of a carbon source organic compound and a ketone-based solvent to obtain a magnesium dispersion. The carbon source organic compound may be at least one of organic acids, hydrocarbons and carbohydrates, may serve as a carbon source in a solid phase, and may be dissolved in a ketone-based solvent. Preference is given to using organic acids.

According to one embodiment of the present invention, the ketone-based solvent may include at least one of acetone and methyl ethyl ketone. For example, acetone may be preferred. When a ketone-based solvent is used, the solubility of organic acids, hydrocarbons, and carbohydrates as organic solvents may be high, and the boiling point may be low, and evaporation and removal may be facilitated by high vapor pressure at room temperature.

According to one embodiment of the present invention, the dispersion may be sonicated for uniform dispersion, and the dispersion may be sonicated for 10 to 100 minutes. When ultrasonication is performed within the above range, the dispersion may be uniformly mixed.

According to one embodiment of the present invention, the prepared magnesium dispersion is dried to obtain a magnesium powder having a coating of a carbon source organic compound. The ketone-based solvent is removed through the drying process, and as a result, a coating of the carbon source organic compound can be formed on the surface of the magnesium powder.

According to one embodiment of the present invention, the drying may be carried out at a temperature of 20 °C to 50 °C for 60 minutes to 120 minutes, and may be performed under vacuum conditions. When drying is performed within the above temperature and time range, the ketone-based solvent is effectively removed, so that a coating can be firmly formed on the surface of the magnesium powder, and damage and oxidation of the magnesium powder can be prevented.

According to one embodiment of the present invention, vacuum drying the magnesium powder coated with the carbon source organic compound at a temperature of 150 °C to 250 °C, 180 °C to 220 °C, or 195 °C to 205 °C; may further include there is. When vacuum drying within the above temperature range, at least one of organic acids, hydrocarbons and carbohydrates contained in the coating is partially or completely pyrolyzed to remove oxygen in the form of organic acids, hydrocarbons, carbohydrates and/or water, alcohol or oxygen gas, and A coating of carbon-containing material can be formed that contains the remaining carbon atom form.

According to one embodiment of the present invention, the vacuum drying may be performed for 40 minutes to 80 minutes.

When the method for producing a coated magnesium powder according to an embodiment of the present invention further includes vacuum drying within the above temperature range, the coated magnesium powder has a high reactive oxygen content while maintaining the amount of carbon contained in the coating. can be reduced to form a more stable coating.

Hereinafter, embodiments according to the present invention may be modified in various other forms, and the scope of the present invention is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present invention to those of ordinary skill in the art.

Example 1

After adding 0.04 g of malic acid (mass fraction of carbon contained in malic acid is about 35.82%) to 10 ml of acetone and stirring to dissolve it completely, add 1 g of magnesium powder (Thanshan weihao, China, 5 μm or less in diameter) and 10 minutes During the ultrasonic treatment (Korea, Saehan Ultrasonic Industries) under 40 kHz frequency condition. After ultrasonic treatment, the powder was dried at room temperature for 60 minutes to obtain a coated magnesium powder.

Example 2

After adding 0.1 g of malic acid to 10 ml of acetone and stirring to dissolve it completely, 1 g of magnesium powder (Korea, Hana AMT, diameter 45 μm or less) was added and an ultrasonic cleaner (Korea, Saehan Ultrasonic Industry) at a frequency of 40 kHz for 10 minutes. conditions were sonicated. After ultrasonication, it was dried at room temperature for 60 minutes, and then placed in a vacuum drying oven (JISICO, Korea) and dried at 200° C. for 1 hour to obtain a coated magnesium powder.

TEM photography and elemental mapping analysis

TEM pictures of the coated magnesium powders prepared in Examples 1 and 2 were taken with a transmission electron microscope (TEM) equipment of JEM 2100F (JEOL, Japan).

1A and 1B are transmission electron microscope (TEM) images of the coated magnesium powder prepared in Example 1. FIG.

1c to 1e are transmission electron microscope (TEM) pictures of the coated magnesium powder prepared in Example 2.

In addition, by EDS element mapping of the coated magnesium powders prepared in Examples 1 and 2 with an energy dispersive spectrometer (EDS) mounted on a JEM 2100F (JEOL, Japan) TEM equipment, Mg, C and O The distribution state of

FIG. 2a is an EDS element mapping result of the coated magnesium powder prepared in Example 1. FIG.

2b to 2d are EDS element mapping results of the coated magnesium powder prepared in Example 2.

Referring to FIGS. 1 and 2 , it can be seen that the coated magnesium powders of Examples 1 and 2 have a form in which a coating is formed on the particle surface. In addition, referring to FIG. 2 , it can be seen that magnesium is distributed in the center, and carbon and oxygen are distributed in the film of the outer surface. That is, it can be confirmed that the magnesium particles are located in the center and the carbon coating is stably formed on the outer surface.

1 and 2, the diameter and coating thickness of the magnesium powder of the coated magnesium powder prepared in Examples 1 and 2 are shown in Table 1 below.

Magnesium particle diameter (μm) Coating thickness (nm) Ratio of carbon coating thickness to magnesium particle diameter (%) Example 1 ~0.08 ~ 3 3.75 ~ 0.15 ~ 5 3.33 ~ 0.12 ~ 4 3.33 ~0.2 ~ 6 3 Example 2 ~ 3 ~ 50 1.67 ~ 30 ~ 300 One ~ 50 ~ 500 One

Referring to Table 1, it can be seen that the coating thickness of the coated magnesium powder prepared in Examples 1 and 2 is as thin as about 1 to 3.75% of the magnesium particle diameter. In addition, it can be seen that as the magnesium particle diameter increases, the thickness of the coating also increases.

Elemental analysis of coated magnesium powder

Carbon and oxygen of the magnesium powders used in Examples 1 and 2 (Reference Examples 1 and 2) and the coated magnesium powders prepared in Examples 1 and 2 with an elemental analyzer (LECO, CS744 and ON836) Elemental content was analyzed.

In Table 2 below, the element contents of carbon and oxygen contained in the magnesium powder used in Examples 1 and 2 and the coated magnesium powder prepared in Examples 1 and 2 are expressed in mass%.

Carbon content (% by mass) Oxygen content (% by mass) Reference Example 1 0.42 0.77 Example 1 1.35 1.09 Reference Example 2 0.09 0.04 Example 2 2.49 0.32

Referring to Table 2, it can be seen that Reference Examples 1 and 2 include carbon and oxygen without a separate processing process. It is considered that this is carbon adsorbed from the outside during the manufacturing process and oxygen forming an oxide film. In addition, in the case of Reference Example 2 having a larger diameter, it can be seen that the carbon and oxygen contents were relatively smaller than those of Reference Example 1 as the magnesium content increased.

When comparing Reference Example 1 and Example 1 and comparing Reference Example 2 and Example 2, it can be seen that the carbon content is increased. This indicates that the carbon coating was successfully formed.

Additionally, as a result of elemental analysis of the magnesium powder prior to vacuum drying in Example 2, carbon contained 2.87 mass % and oxygen 1.38 mass %. That is, it can be seen that a large amount of oxygen has been removed with water or gaseous oxygen by vacuum drying at a high temperature, and it can be seen that malic acid, an organic acid containing oxygen included in the coating, is decomposed.

Summarizing the above results, it can be seen that in the coated magnesium powder according to an embodiment of the present invention, a coating including a carbon-containing material is located on the outer surface of the magnesium powder particle.

Claims (11)

magnesium powder; and
a coating disposed on the magnesium powder surface and comprising a carbon-containing material;
including,
wherein the carbon-containing material comprises at least one of maleic acid, fumaric acid, succinic acid, malic acid, formic acid, acetic acid, propionic acid, butyric acid, lactic acid, tartaric acid and citric acid.
delete delete According to claim 1,
The coated magnesium powder, wherein the carbon-containing material is included in an amount of 1% by mass to 5% by mass based on carbon atoms.
According to claim 1,
The thickness of the coating is 0.1% to 10% of the diameter of the magnesium powder coated magnesium powder.
According to claim 1,
The magnesium powder is coated magnesium powder having an average diameter of 0.05 μm to 50 μm.
adding magnesium powder to a mixture of a carbon source organic compound and a ketone-based solvent to obtain a magnesium dispersion; and
drying the magnesium dispersion to obtain a magnesium powder coated with a carbon source organic compound; A method for producing the coated magnesium powder of any one of claims 1 and 4 to 6, comprising a.
8. The method of claim 7,
The ketone-based solvent is a method for producing a coated magnesium powder comprising at least one of acetone and methyl ethyl ketone.
8. The method of claim 7,
The method for producing a coated magnesium powder, wherein the carbon source organic compound comprises at least one of an organic acid, a hydrocarbon and a carbohydrate.
8. The method of claim 7,
The drying of the magnesium dispersion is a method for producing a coated magnesium powder is carried out for 60 minutes to 120 minutes at a temperature of 20 ℃ to 50 ℃.
8. The method of claim 7,
vacuum drying the magnesium powder coated with the carbon source organic compound at a temperature of 180°C to 220°C; A method for producing a coated magnesium powder further comprising a.

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