KR102266797B1 - Multi-dimensional zinc oxide coated iron oxide and manufacturing method thereof - Google Patents

Abstract

The present invention relates to zinc oxide having a multidimensional shape coated with iron oxide, and more particularly, to zinc oxide (ZnO) having a multidimensional shape in two or three dimensions using a simple method using a reduced pressure filtration method or a stirring aging method. By coating (Fe ₂ O ₃ ), it relates to a multidimensional zinc oxide coated with iron oxide capable of improving the electromagnetic wave disturbance effect, and a method for manufacturing the same.

Description

Multi-dimensional zinc oxide coated with iron oxide and manufacturing method thereof {MULTI-DIMENSIONAL ZINC OXIDE COATED IRON OXIDE AND MANUFACTURING METHOD THEREOF}

The present invention relates to multi-dimensional zinc oxide (ZnO) that can be applied to electromagnetic wave absorbers, and more particularly, to a center of two-dimensional or three-dimensional multi-dimensional zinc oxide (ZnO) by a filtration method or a stirring aging method. (Core) It relates to a multi-dimensional zinc oxide coated with iron oxide, which has improved properties of disturbing electromagnetic waves by coating a particle-type or shell-type iron oxide (Fe ₂ O _{3 ) on the surface, and a method for manufacturing the same.}

When an electromagnetic wave encounters an object, the electromagnetic wave is reflected and returned, and by analyzing it, the position, size, and shape of the object can be known. Stealth technology disturbs the characteristics of these electromagnetic waves so that they are not easily detected by radar, declination trackers, sonar, etc., by using a coating with an electromagnetic wave absorber that absorbs electromagnetic waves or by making a certain inclination angle on the surface of the aircraft. It is a method of reducing the amount of electromagnetic waves that are scattered and returned.

Coatings containing electromagnetic wave absorbers in aircraft such as aircraft are advantageous to have a thin coating film thickness in order to increase the weight reduction characteristics. The radio wave absorption rate is maximized when the coating film thickness is 1/4 of the wavelength (λ), and such a coating film The thickness is inversely proportional to the square root of the magnetic permeability and permittivity of the constituent material. Therefore, in order to manufacture a thin electromagnetic wave absorber, it is advantageous to select a material having high magnetic permeability and dielectric constant, and there is a ferrite series, which is generally widely used.

Korean Patent Publication No. 10-2019-0081235

The present invention relates to iron oxide that can be used as an electromagnetic wave absorber that can increase the effect of electromagnetic wave absorption by coating _{iron oxide (Fe 2} O ₃ ) on the surface of zinc oxide (ZnO) having a two-dimensional or three-dimensional multidimensional shape to disturb electromagnetic waves. An object of the present invention is to provide the coated zinc oxide having a multidimensional shape and a manufacturing method thereof.

In order to achieve the above object, in the method for producing zinc oxide of a multidimensional shape coated with iron oxide of the present invention, zinc oxide of a multidimensional shape and iron pentacarbonyl are respectively added to a solvent and stirred to obtain a zinc oxide solution and iron pentacarbonyl. A solution preparation step of preparing a solution, a first filtration step of filtering the zinc oxide solution under reduced pressure using filter paper, a second filtration step of filtration under reduced pressure of the iron pentacarbonyl solution using the filter paper that has passed the first filtration step; and a drying step of drying the material remaining on the filter paper without being filtered after performing the second filtration step.

When the number of filtration under reduced pressure in the second filtration step is increased, the coating thickness of the iron oxide is increased.

The number of times of reduced pressure filtration and the coating thickness of iron oxide in the second filtration step is characterized in that the following empirical formula 1.

[Empirical Formula 1]

In the above empirical formula 1, x is the number of filtration under reduced pressure, and y is the average thickness of the iron oxide coated on the multidimensional zinc oxide surface.

The average thickness of the iron oxide coated on the multidimensional zinc oxide surface through the second filtration step may be 10 nm to 1000 nm, and more preferably, may be coated to a thickness of 50 nm to 1000 nm.

In addition, the multidimensional zinc oxide coated with iron oxide of the present invention formed by the stirring aging method is aged by stirring and aging the multidimensional zinc oxide in an iron pentacarbonyl solution containing iron pentacarbonyl, and the stirring and aging iron pentakibo The iron oxide may be coated on the multidimensional zinc oxide surface by a method of drying the neil solution.

Another method for producing zinc oxide of a multi-dimensional shape coated with iron oxide of the present invention includes a solution preparation step of preparing an iron pentacarbonyl solution by adding iron pentacarbonyl to a solvent and stirring, and adding the multi-dimensional shape to the iron pentacarbonyl solution. It may include a stirring aging step of adding zinc oxide and aging while stirring, and a drying step of drying the iron pentacarbonyl solution that has undergone the stirring and aging step.

The stirring and aging step is preferably performed by stirring at a stirring speed of 30 RPM to 70 RPM for 12 hours to 48 hours.

When the stirring aging time is increased in the stirring aging step, the coating thickness of the iron oxide is increased.

In the stirring aging step, the stirring aging time and the coating thickness of iron oxide are characterized by the following empirical formula 2.

[Equation 2]

In Equation 2, x is the stirring aging time, and y is the average thickness of the iron oxide coated on the multidimensional zinc oxide surface.

The average thickness of the iron oxide coated on the multidimensional zinc oxide surface through the stirring and aging step may be 10 nm to 1000 nm, and more preferably, it may be coated to a thickness of 50 nm to 1000 nm.

In the above-described method for producing a multidimensional zinc oxide coated with iron oxide of the present invention, the drying step is preferably performed at a temperature of 80° C. to 120° C. for 1 second to 5 minutes.

In the method for producing zinc oxide of a multidimensional shape coated with iron oxide of the present invention, the solvent used for preparing the zinc oxide solution and the iron pentacarbonyl solution is an alcohol-based organic solvent having 1 to 10 carbon atoms. It can be used, and specifically, it is preferable to use methanol, ethanol, etc. as an alcohol-based organic solvent having 1 to 4 carbon atoms.

As the method for producing the multidimensional zinc oxide coated with iron oxide of the present invention described above, it is possible to prepare the multidimensional zinc oxide coated with iron oxide by a reduced pressure filtration method or a stirring aging method.

The iron oxide (Fe ₂ O ₃ ) used in the present invention is a material generally used in electromagnetic wave absorbers, and is coated on the surface of zinc oxide (ZnO) having a two-dimensional or three-dimensional shape with a certain angle to disturb electromagnetic waves. By doing so, the effect of disturbance of electromagnetic waves can be improved.

In addition, the manufacturing method of multidimensional zinc oxide coated with iron oxide presented in the present invention is irrespective of the characteristics of zinc oxide, which is weak to acid, wetted in a short time using a filtration method at room temperature, and then fired at a high temperature during drying. It is possible to control the thickness of iron oxide on the surface of multidimensional zinc oxide by producing iron oxide and coating it on the surface of zinc oxide and by producing iron oxide on the surface of zinc oxide for a sufficient time under stirring and aging and coating it on the surface of zinc oxide. Since the manufacturing process is simple, there is an effect that can be applied in many fields.

1 is a flowchart showing a method for manufacturing a multidimensional zinc oxide coated with iron oxide according to an embodiment of the present invention.
2 and 3 are graphs of the average thickness of the coated iron oxide according to Examples 1 to 6 of the present invention.
4A to 4E are field emission scans of the multidimensional zinc oxide coated with iron oxide prepared by the method for manufacturing the multidimensional zinc oxide coated with iron oxide according to Comparative Examples 1, 3, and 6 of the present invention; An electron microscope (Field Emission Scanning Electron Microscope, FE-SEM) image is shown.
5 is an X-ray diffraction (XRD) analysis result of a multidimensional zinc oxide coated with iron oxide prepared by the method for manufacturing a multidimensional zinc oxide coated with iron oxide according to an embodiment of the present invention; will be.

The technical advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, only this embodiment allows the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

Unless otherwise defined, all terms including technical and scientific terms used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention pertains. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless specifically defined explicitly.

1 is a flowchart of a method for manufacturing a multi-dimensional zinc oxide coated with iron oxide according to the present invention. As shown in FIG. 1, the method for manufacturing a multi-dimensional zinc oxide coated with iron oxide according to the present invention is performed by mixing zinc oxide with an alcohol-based solvent. A zinc oxide solution is prepared (S110), an iron pentacarbonyl (Fe(CO) ₅ ) solution is prepared (S120), and the prepared iron pentacarbonyl solution and the prepared zinc oxide solution are filtered under reduced pressure or aged under stirring. _{After coating iron pentacarbonyl (Fe(CO) 5} ) on the surface of multidimensional zinc oxide using a method selected from methods (S200), it is dried at 100 ° C. for 1 second to 10 minutes by heat treatment drying ( S300) By changing the iron pentacarbonyl (Fe(CO) ₅ ) coated on the zinc oxide surface into iron oxide (Fe ₂ O ₃ ) to produce a zinc oxide composite, a multidimensional zinc oxide coated with iron oxide is prepared (S400) ). At this time, in the case of manufacturing the multidimensional zinc oxide coated with iron oxide by the reduced pressure filtration method, the reduced pressure filtration process is repeated one or more times again using an iron pentacarbonyl solution before the heat treatment drying (S300).

In the present specification, multi-dimensional zinc oxide means two-dimensional or three-dimensional zinc oxide, for example, two-dimensional zinc oxide in a sheet shape, or a certain angle. It may be a three-dimensional shape consisting of, or a cylindrical, cylindrical or spherical zinc oxide having a certain radius R.

Here, the precursor used to prepare multidimensional zinc oxide coated with iron oxide is iron pentacarbonyl (Fe(CO) ₅ ), which is produced by coating iron oxide particles on the surface of zinc oxide in a relatively short time. The solvent used for the reaction may be an alcohol-based organic solvent having 1 to 10 carbon atoms, such as methanol or ethanol.

In addition, in the second filtration step of coating iron pentacarbonyl in the reduced pressure filtration method among the manufacturing method of the iron oxide-coated multidimensional zinc oxide of the present invention, the number of filtrations may be 9 or more, and in the stirring aging method, stirring aging time It is also produced more than 48 hours, but in this case, iron pentacarbonyl (Fe(CO) ₅ ), which is a precursor used, is used a lot, and this is inefficient because the yield is lowered and the manufacturing cost is also increased.

Hereinafter, the characteristics and effects of the above-described multidimensional zinc oxide-coated zinc oxide manufacturing method and the iron oxide-coated multi-dimensional zinc oxide prepared through the examples and comparative examples will be described in more detail.

In Example 1, 0.7 g of zinc oxide (ZnO) and _{10 mL of iron pentacarbonyl (Fe(CO) 5} ) 1M having a two-dimensional or three-dimensional multidimensional shape were added to 100 mL of methanol, respectively, and stirred for 20 minutes until completely dispersed. to prepare a zinc oxide solution and an iron pentacarbonyl solution. Thereafter, the zinc oxide solution is filtered so that only zinc oxide remains on the filter paper using a filtering device and a pressure reducing pump, and then the iron pentacarbonyl solution is filtered once on the filter paper on which the zinc oxide remains. After the filtration was completed, it was dried in a hot air dryer at a temperature of 100° C. for 1 minute to prepare a multidimensional zinc oxide powder coated with iron oxide.

In Example 2, a multidimensional zinc oxide powder coated with iron oxide was prepared in the same manner as in Example 1, except that the iron pentacarbonyl solution was filtered three times on the filter paper on which the zinc oxide remained.

In Example 3, a multidimensional zinc oxide powder coated with iron oxide was prepared in the same manner as in Example 1, except that the iron pentacarbonyl solution was filtered five times on the filter paper on which the zinc oxide remained.

Example 4 is an iron pentacarbonyl (Fe(CO) ₅ ) solution, and 0.01M of zinc oxide (ZnO) having a multidimensional shape in two or three dimensions is added to 10 mL of iron pentacarbonyl 5M, and zinc oxide is iron pentakybonyl. Stir slowly at 50 RPM for 12 hours to fully wet the solution. After the stirring was completed, it was dried in a hot air dryer at a temperature of 100° C. for 1 minute to prepare a multidimensional zinc oxide powder coated with iron oxide.

In Example 5, iron oxide was coated in the same manner as in Example 4, except that zinc oxide (ZnO) was added to the iron pentacarbonyl (Fe(CO) _{5 ) solution and the stirring time was changed to 24 hours.} A multidimensional zinc oxide powder was prepared.

In Example 6, iron oxide was coated in the same manner as in Example 4, except that zinc oxide (ZnO) was added to the iron pentacarbonyl (Fe(CO) _{5 ) solution and the stirring time was changed to 48 hours.} A multidimensional zinc oxide powder was prepared.

Comparative Example 1 was the same as the method of Example 1, except that the _{iron pentacarbonyl (Fe(CO) 5} ) solution was not filtered in the process of manufacturing the multidimensional zinc oxide coated with iron oxide of Example 1 carried out.

In order to measure the physical properties of the multidimensional zinc oxide coated with iron oxide, which is a material prepared in Examples 1 to 6 and Comparative Example 1 described above, it was dried in powder form and evaluated. The powder was dried in a vacuum oven at 45° C. for 4 hours, and the results are shown in Table 1 and FIGS. 2 and 3, respectively.

division _{Fe 2} O ₃ coating thickness on ZnO _{Fe 2} O ₃ area range coated on ZnO _{Fe 2} O ₃ coating form coated on ZnO Example 1 5-15nm 10-30% granular Example 2 25-50nm 50-70% granular Example 3 50-100nm 70-100% granular Example 4 25-50nm 10-30% granular Example 5 50-100nm 30-70% shell type Example 6 100-175nm 90-100% shell type Comparative Example 1 No coating formed No coating formed No coating formed

As shown in Table 1, it can be seen that the coating thickness of the iron oxide coated on the zinc oxide surface also increases as the number of times of reduced pressure filtration or the stirring aging time increases. It was confirmed that the iron oxide was not coated on the surface. As such, it can be seen that the coating thickness of the iron oxide is possible because the coating thickness of the iron oxide coated on the zinc oxide surface is controlled according to the number of times of reduced pressure filtration or the stirring and aging time.

2 is a graph showing the change in the average thickness of iron oxide coated on multidimensional zinc oxide through the filtration method according to Examples 1 to 3 of the present invention.

As shown in FIG. 2 , in the zinc oxide powder prepared through the filtration method, the thickness of the iron oxide coated on the multidimensional zinc oxide surface increases as the number of times of reduced pressure filtration increases, and the change in the iron oxide coating thickness through the filtration method increases. It can be expressed as in Equation 1 below with an accuracy of 98.4%.

[Empirical Formula 1]

In the above empirical formula 1, x is the number of filtration under reduced pressure, and y is the average thickness of the iron oxide coated on the multidimensional zinc oxide surface.

3 is a graph showing changes in the average thickness of iron oxide coated on multidimensional zinc oxide according to Examples 4 to 6 of the present invention.

As shown in FIG. 4 , in the zinc oxide powder prepared through the stirring aging method, the thickness of the iron oxide coated on the multidimensional zinc oxide surface increases as the stirring aging time increases, and the thickness of the iron oxide coating through the stirring aging method increases. The relational expression for change has an accuracy of 99.6% and can be expressed as Equation 2 below.

[Equation 2]

In Equation 2, x is the stirring aging time, and y is the average thickness of the iron oxide coated on the multidimensional zinc oxide surface.

As in the embodiments of the present invention, the average thickness of the iron oxide coated on the multidimensional zinc oxide surface through the reduced pressure filtration method and the stirring aging method may be 10 nm to 1000 nm, and more preferably 50 nm to 1000 nm thick. However, it is not necessarily limited thereto, and may be coated in various thicknesses.

As another physical property evaluation, the multidimensional zinc oxide coated with iron oxide of Comparative Examples 1, 3 and 3 was confirmed by measuring it with a Field Emission Scanning Electron Microscope (FE-SEM), In the case of Examples 3 and 6, the epoxy resin and the powders of Examples 3 and 6 were mixed in a certain ratio to measure the powder cross section, dried, and measured with a field emission scanning electron microscope (FE-SEM). did. Such field emission scanning electron microscopy (FE-SEM) measurement results are shown in FIGS. 4A to 4E .

4a shows that the zinc oxide powder prepared according to Comparative Example 1 was not coated with iron oxide on the surface of the zinc oxide.

4b is a shape of the surface of the zinc oxide powder prepared according to Example 3, and FIG. 4c is a cross-sectional view of the zinc oxide powder prepared according to Example 3, as in FIG. 4c, iron oxide (Fe) on the surface of zinc oxide (ZnO). _It can be seen that 2 O _{3 ) is coated.}

4D is a shape of the surface of the zinc oxide powder prepared according to Example 6, and FIG. 4E is a cross-sectional view of the zinc oxide powder prepared according to Example 6 As shown in FIG. 4E, a multidimensional shape with a diameter of about 203 nm It can be seen that _{iron oxide (Fe 2} O ₃ ) of about 105 nm is coated on the surface of zinc oxide (ZnO).

In addition, in order to confirm the surface area characteristics of zinc oxide having a multidimensional shape coated with iron oxide, X-ray diffraction (XRD) was performed on the zinc oxide powder obtained in Example 6 and the zinc oxide powder of Comparative Example 1 as a control. Analysis was performed, and the results are shown in FIG. 5 .

As shown in FIG. 5 , when the peaks of the zinc oxide powder of Example 6 and the zinc oxide powder of Comparative Example 1 are compared, when the peak of Example 6 is reduced, it is a zinc oxide (ZnO) having a multidimensional shape. ) It can be seen that the surface of the iron oxide (Fe ₂ O ₃ ) is coated to form a low crystallinity peak.

Claims (15)

A solution preparation step of preparing a zinc oxide solution and an iron pentacarbonyl solution by adding multidimensional zinc oxide and iron pentacarbonyl to an alcohol-based organic solvent having 1 to 10 carbon atoms, respectively, and stirring the mixture;
a first filtration step of filtering the zinc oxide solution under reduced pressure using filter paper;
a second filtration step of filtering the iron pentacarbonyl solution under reduced pressure using the filter paper that has undergone the first filtration step; and
and a drying step of drying the material remaining on the filter paper without being filtered after performing the second filtration step. According to claim 1,
A method for producing a multidimensional zinc oxide coated with iron oxide, characterized in that the coating thickness of the iron oxide increases when the number of times of filtration under reduced pressure in the second filtration step is increased. According to claim 1,
In the second filtration step, the number of times of reduced pressure filtration and the coating thickness of the iron oxide are the following empirical formula 1, wherein the iron oxide-coated multidimensional zinc oxide manufacturing method.
[Empirical Formula 1]

(In the above empirical formula 1, x is the number of filtration under reduced pressure, and y is the average thickness of iron oxide coated on the multidimensional zinc oxide surface) According to claim 1,
An average thickness of the iron oxide coated on the surface of the multi-dimensional zinc oxide through the second filtration step is 10 nm to 1000 nm. According to claim 1,
The drying step is a method for producing a multidimensional zinc oxide coated with iron oxide, characterized in that the drying for 1 second to 5 minutes at a temperature of 80 ℃ to 120 ℃. delete A multidimensional zinc oxide coated with iron oxide produced by the method for manufacturing a multidimensional zinc oxide coated with iron oxide according to any one of claims 1 to 5. a solution preparation step of preparing an iron pentacarbonyl solution by adding iron pentacarbonyl to an alcohol-based organic solvent having 1 to 10 carbon atoms and stirring;
a stirring aging step of adding multidimensional zinc oxide to the iron pentacarbonyl solution and aging while stirring; and
and a drying step of drying the iron pentacarbonyl solution that has undergone the stirring and aging step. 9. The method of claim 8,
The stirring and aging step is a method for producing a multidimensional zinc oxide coated with iron oxide, characterized in that the aging is performed by stirring at a stirring speed of 30 RPM to 70 RPM for 12 hours to 48 hours. 9. The method of claim 8,
A method for producing a multidimensional zinc oxide coated with iron oxide, characterized in that the coating thickness of the iron oxide increases when the stirring aging time is increased in the stirring aging step. 9. The method of claim 8,
In the stirring aging step, the stirring aging time and the iron oxide coating thickness are the following empirical formula 2, wherein the iron oxide-coated multidimensional zinc oxide manufacturing method.
[Equation 2]

(In the above empirical formula 2, x is the stirring aging time, and y is the average thickness of the iron oxide coated on the multidimensional zinc oxide surface) 9. The method of claim 8,
An average thickness of the iron oxide coated on the surface of the multi-dimensional zinc oxide through the stirring and aging step is 10 nm to 1000 nm. 9. The method of claim 8,
The drying step is a method for producing a multidimensional zinc oxide coated with iron oxide, characterized in that the drying for 1 second to 5 minutes at a temperature of 80 ℃ to 120 ℃. delete 14. A multidimensional zinc oxide coated with iron oxide produced by the method for manufacturing a multidimensional zinc oxide coated with iron oxide according to any one of claims 8 to 13.

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