KR100767719B1 - Ti-based amorphous nano-powders and method of preparation thereof - Google Patents

Abstract

Titanium-based amorphous nanopowders are provided to be produced by a very simple and controllable selective corrosion method and have a spherical shape and a smooth surface. Ti-based amorphous nanopowders is represented by a chemical formula of Ti_(100-a-b-c-d)Al_aCo_bY_cI_d, wherein a, b, c, and d satisfy 10<=a<=30, 10<=b<=30, 1<=c<=10, and 0.1<=d<=5 in terms of atom%, and I is an impurity. The Ti-based amorphous nanopowders are prepared by the steps of: melting and mixing Ti, Y, Al, Co, and other impurity; cooling the molten metals to form two-phase amorphous alloys; and removing a continued base of the two-phase amorphous alloys by selective corrosion to form amorphous powders.

Description

Ti amorphous nano powder and its manufacturing method {Ti-BASED AMORPHOUS NANO-POWDERS AND METHOD OF PREPARATION THEREOF}

1 (a) to (c) show two phases each having a composition of (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) when α is 0, 100, or 50, respectively. XRD graph of the amorphous alloy.

FIG. 2 is a differential scanning calorimetry (DSC) curve of a Ti-Y-Al-Co amorphous spun ribbon in the form of a ribbon formed by a melt spinning method.

3 (a) and 3 (b) are TEM images and SAEDP images of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Y ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloys, respectively.

4 is a binary phase diagram of a Ti-Y alloy.

5A and 5B are Pourbaix diagrams of Y and Ti, respectively.

6 shows Ti ₅₆ Al ₂₄ Co ₂₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ in 0.1M HNO ₃ solution. Co ₂₀ ) ₆₅ and Y ₅₅ Al ₂₄ Co ₂₀ alloy potential curves.

7A and 7B are SEM photographs and XRD graphs after selective corrosion of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloys, respectively.

7C and 7D show TEM and SAEDP images of amorphous powders formed from (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloys, respectively, and (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ TEM and SAEDP images of amorphous powders formed from Al ₂₄ Co ₂₀ ) ₆₅ alloy.

FIG. 8 shows EDS analysis of amorphous powders obtained by selective corrosion of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloys.

FIG. 9 is a SEM photograph showing that Ti alloy is attached to Y base by partially dissolving the (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloy.

The present invention relates to a Ti-based amorphous nanopowder and a method for manufacturing the same, and more particularly, to a Ti-based amorphous nanopowder prepared by removing a matrix from a two-phase amorphous alloy and a method for producing the same.

Most metal alloys form crystal phases in which the arrangement of atoms is regular at the time of solidification from the liquid phase. However, if the cooling rate at the time of solidification is sufficiently above the threshold value to limit the nucleation and growth of the crystal phase, the irregular atomic structure of the liquid phase can remain intact. Such alloys are commonly referred to as amorphous alloys. Amorphous alloys have tensile strengths that are two to three times higher than crystalline alloys, and are known to be excellent in corrosion resistance due to the uniformity of the structure where no grain boundaries exist.

On the other hand, amorphous powders can be used as building blocks for the fabrication of nano-structured materials, reinforcement of polymeric materials, alloys with low melting points, and catalysts. It has been found that the properties of matter change significantly.

 In particular, in 1959, by Richard P. Feynman, and by Eric K. Drexel over 20 years ago, a whole new field of study was undertaken to control the physical and chemical properties of nanoscale materials. Today, these nanostructured materials are expected to be a major part of future electrical, magnetic and mechanical devices.

Processes for making these nanomaterials include chemical vapor deposition, physical vapor deposition, precipitation, reactive sputtering, laser pyrolysis, and arc plasma processes. process, pulse wire explosion, mechanical alloying, grinding or sol-gel technique.

However, most of these processes usually require complex processes and expensive equipment and often cannot control the atomic structure. For example, chemical vacuum deposition, arc plasma processing, pulsed wire explosion, or mechanical alloying can form meta-stable structures such as amorphous, but only stable atomic structures, such as precipitation and sol-gel, Is achieved.

In addition, in most of the processes described above, it is difficult for the amorphous powder to have a spherical and smooth surface, and the powders aggregate together.

In addition, there is a problem that the size distribution of the amorphous powder is relatively small, it is difficult to control the size of the amorphous powder according to the initial composition, and the structure of the amorphous powder cannot be confirmed by the initial state of the alloy.

In order to solve the above problems, the present invention is to provide a spherical amorphous nano-powder formed by removing the matrix by the method of selective corrosion in the two-phase amorphous alloy.

In addition, the present invention is to provide a method for producing the above-mentioned spherical amorphous nano powder.

The Ti-based amorphous nanopowder according to the present invention is represented by the formula Ti _100-abcd Al _a Co _b Y _c I _d , wherein a, b, c and d are atomic%, respectively 10 ≦ a ≦ 30, 10 ≦ b≤30, 1≤c≤10 and 0.1≤d≤5 are satisfied, and I is an impurity.

In this case, the Ti-based amorphous nano-powder is represented by the formula (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) , wherein α is a two-phase amorphous having 30 ≦ α ≦ 50 as the atomic% It is preferably formed by selective corrosion from the alloy.

Further, it is preferable that the atomic% of Al is 15 to 28, and the atomic% of Co is 15 to 30 in Ti-Al-Co which is the first amorphous phase of the two-phase amorphous alloy.

Further, it is preferable that the atomic% of Al in the Y-Al-Co which is the second amorphous phase of the two-phase amorphous alloy is 20 to 28, and Co is 15 to 25.

In addition, the two-phase amorphous alloy is preferably formed in the form of a ribbon.

In addition, the ribbon-shaped two-phase amorphous alloy is preferably 5㎛ 50㎛ thickness, 1mm to 10mm width.

In addition, the selective corrosion is preferably carried out in diluted HNO ₃ solution.

Further, the selective corrosion is preferably made of the two-phase amorphous alloy as an active electrode.

On the other hand, the Ti-based amorphous nano powder manufacturing method according to the present invention comprises the steps of melting and mixing Ti, Y, Al, Co and other impurities to form the first ingot (ingot) having a desired composition, the mixed molten metal Quenching to form a two-phase amorphous alloy; Selective corrosion removes the continuous amorphous matrix of the amorphous alloy to form an amorphous powder.

At this time, the step of forming the amorphous alloy is represented by the formula (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) , wherein α is 30≤α≤50 in atomic% It is desirable to form an amorphous alloy of the phase.

Further, it is preferable that the atomic% of Al is 15 to 28, and the atomic% of Co is 15 to 30 in Ti-Al-Co which is the first amorphous phase of the two-phase amorphous alloy.

Further, it is preferable that the atomic% of Al in the Y-Al-Co which is the second amorphous phase of the two-phase amorphous alloy is 20 to 28, and Co is 15 to 25.

In addition, the two-phase amorphous alloy is preferably formed in the form of a ribbon.

In addition, the ribbon of the two-phase amorphous alloy is preferably 5㎛ to 50㎛ thickness, 1mm to 10mm width.

In addition, the chemical selective corrosion is preferably carried out in diluted HNO ₃ solution.

It is also preferable to use the two-phase amorphous alloy as the active electrode in the chemical selective corrosion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. These examples are merely to illustrate the invention, but the invention is not limited thereto.

A brief summary of the preparation method of Ti-based amorphous nanopowders is as follows. First, an amorphous alloy ribbon is formed by rapid cooling. Next, the amorphous alloy ribbon is selectively corroded by an electrochemical method to remove specific elements to form amorphous nanopowders.

To form the first ingot, Al, Co and other impurities are melted and mixed to help form Ti, Y and amorphous alloys. At this time, the melt is such that in the formula (Ti-Al-Co) _α (Y-Al-Co) _(100-α) , α has a composition of 30 to 50 as atomic%.

Meanwhile, the atomic% of Al in the Ti-Al-Co which is the first amorphous phase is preferably 15 to 28, and the atomic% of Co is 15 to 30, and the atom of Al in Y-Al-Co which is the second amorphous phase. It is preferable that% is 20-28, and Co is 15-25. Al and Co are difficult to form amorphous beyond this composition range.

Subsequently, the amorphous alloy is manufactured in the form of a thin ribbon by supercooling and solidifying below the solidification temperature of Ti of 450 ° C.

In this case, in order to form an amorphous alloy having two phases, the incompatibility of the constituent elements is required. Since Ti and Y are not mixed with each other, the Ti-Al-Co phase is cooled when the melt of Ti-Y-Al-Co is cooled. There is a tendency to separate into and Y-Al-Co phase. Wherein both phases are amorphous.

In this case, different microstructures are formed according to the composition of the (Ti-Al-Co) _α (Y-Al-Co) _(100-α) alloy. In Ti-rich alloys (70≤α≤85), Y particles are buried in Ti amorphous matrix when cooled at a high rate of 10 ⁵ K / s, and at 60≤α≤70, the alloys form interconnected structures. do. In contrast, the microstructure of the Y-based alloy (20 ≦ α ≦ 60) is composed of Ti particles dispersed into a continuous Y amorphous matrix.

That is, the size of the particles is related to the composition of the alloy. The smaller the content of Ti, the smaller the size of the particles. As a result, the microstructure and particle size are determined by the original alloy composition and cooling rate. Therefore, the size of the desired amorphous powder can be controlled according to the initial composition.

In this embodiment, since the composition ratio is optimized so that the atomic percentage α is 30 to 50, Ti particles can be formed to be dispersed in a continuous amorphous Y base. That is, when it is out of the said composition range, the biphasic amorphous alloy which has an appropriate structure cannot be obtained. In addition, Al and Co are difficult to form amorphous outside the above-described composition range.

Next, amorphous nanopowders are prepared using different electrochemical properties between solid phases. If the electrochemical properties of the elements that are not intermixed are different, only certain elements constituting the ribbon can be removed by selective dealloying. By removing a specific element, the amorphous alloy can be formed into an amorphous nano powder.

Selective corrosion is the extraction of any one or two or more of the components of a two-phase amorphous alloy. That is, a two-phase amorphous alloy consists of two or more different electrochemical properties of constituents. In a two phase material consisting of individual particles, if a known constituent is more reactive, The constituent elements are removed to form an amorphous powder.

 This can be achieved by immersing the material in a well-selected chemical solvent or by electrochemistry, which can be carried out more quickly and more easily control the powder formation behavior. At this time, when a two-phase amorphous alloy is used as an electrode in an electrochemical cell and a certain range of voltage is applied, less rare metals are dissolved. If an electrochemical solvent is selected, selective dissolution occurs, which is undesirable. For ease of control, it is desirable that one element is dissolved in the electrolyte and the other element remains intact due to the difference in potentials forming the ions. In the case of continual removal of the more inactive components, the particles fall out of the mass and are extracted from the solution.

In order for selective corrosion to occur, two conditions must be met along with the difference in electrochemical properties. One is the critical potential (Ec) and the other is the partitioning limit. Selective corrosion occurs at the minimum applied critical potential, which exceeds the potential potential for selective corrosion. In addition, the critical potential depends on the concentration of more inert elements and the properties of the oxide layer formed on the surface.

And if the concentration of less active elements exceeds a certain concentration, selective corrosion occurs. When the critical potential Ec becomes almost the same as the redox potential of the oxide, the concentration of the rare element is called the separation limit of the specific oxide, in which case no selective corrosion occurs.

In the embodiment of the present invention, an amorphous alloy composed of two amorphous phases of Ti-Y-Al-Co is used. Y does not mix with Ti in this alloy. However, Ti-Al-Co and Y-Al-Co can form an amorphous phase. Therefore, when preparing an alloy having a composition similar to that of (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) , Ti is continuous when α is 30 ≦ α ≦ 50. An amorphous alloy having a structure spreading to Y base can be produced.

When selective corrosion is applied to the alloy, it is represented by the formula Ti _100-abcd Al _a Co _b Y _c I _d by removing Y from the Y-Al-Co amorphous phase, where a, b, c and d are atoms As a%, 10? A? 30, 10? B? 30, 1? C? 10, and 0.1? D? 5, respectively, and Ti-based amorphous nanopowders in which I is an impurity can be produced. Hereinafter, an experimental example of the present invention will be described in detail with reference to the accompanying drawings.

Microstructure of Amorphous Ribbon

First, Ti-Y-Al-Co amorphous alloy was prepared by the following method. The molten metal comprising Ti, Al, Co and Y was cooled at a rate of over 10 ⁵ K / sec to form a two-phase amorphous alloy of Ti-Al-Co alloy and Y-Al-Co alloy. For example, Ti-based and Y-based amorphous alloys were prepared in the form of thin ribbons having a thickness of 5 μm to 50 μm and a width of 1 mm to 10 mm by a melt spinning method.

In addition, as described above, Ti and Y have a property that they do not mix well with each other in the solid state. Therefore, when preparing an amorphous alloy from molten metal containing Ti, Al, Y and Co, a two-phase amorphous alloy separated into Ti-Al-Co and Y-Al-Co was formed.

1 (a) to (c) show two-phase amorphous compositions having (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) when α is 0, 100, and 50, respectively. The XRD graph of the alloy is shown. In the experimental example of the present invention, as a two-phase amorphous alloy, a two-phase amorphous alloy when α was 0, 50, or 100 was produced in the form of a ribbon.

As shown, when α = 50 (FIG. 1 (c)), it has two halo peaks at diffraction angles 2θ of 28 ° to 38 ° and 38 ° and 40 °. The halo peak means that the alloys have an amorphous phase in the state of rapid solidification. The two broad halo peaks also indicate the presence of two amorphous phases. This is because the atomic radius is different in the Ti-based amorphous phase and the Y-based amorphous phase.

Referring to the XRD graphs of the Ti-Al-Co alloy (α = 100, (b) of FIG. 1) and the Y-Al-Co alloy (α = 0, (a) of FIG. 1), (Ti ₅₆ Al ₂₄ Co ₂₀ ) The halo peaks appearing at two diffraction angles in the ₅₀ (Y ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloy correspond to the Y-rich amorphous phase and the Ti-rich amorphous phase, respectively.

Thermal Properties of Amorphous Alloy Ribbons

2 shows a differential scanning calorimetry (DSC) curve of a Ti-Y-Al-Co amorphous alloy ribbon in the form of a ribbon formed by a melt spinning method. As shown, the DSC curve indicates that the glass transition is formed in the range of 650 K to 780 K depending on the composition of the amorphous alloy. In addition, one or two exothermic peaks appear in the range of 700K to 850K. The exothermic peaks indicate that the crystallization of the Y and Ti phases proceeds, respectively.

The peak at high temperature corresponds to the Ti phase and the peak at low temperature corresponds to the Y phase. In addition, two exothermic peaks indicate that there are two distinguishable amorphous phases. However, when the value of α was small or large, the volume fraction of the phase was small, and no exothermic peak that could be observed by DSC analysis was found.

Microstructure Observation of Two-Phase Amorphous Alloy Ribbons

3 (a) and 3 (b) are TEM images and SAEDP images of two-phase amorphous alloys represented by (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Y ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ , respectively.

As shown in FIG. 3A, the microstructure of the Ti-Y-Al-Co two-phase amorphous alloy formed in the form of a ribbon can be observed by TEM. In other words, it is possible to confirm the existence of two distinct phases, in which one phase forming spherical particles in the dark part is buried in a continuous matrix in the bright part. In this case, the spherical formation of the particles indicates that phase separation occurs in the liquid state. Therefore, when the amorphous powder is formed, it is possible to prevent the powders from aggregating seriously with each other and to form a smooth spherical powder.

In addition, as shown in FIG. 3B, selected area electron diffreaction patterns (SAEDP) in the selected range of the Ti-Y-Al-Co ribbon show two circles. As shown in the XRD graph in FIG. 1 described above, the inner circle corresponds to the Y phase and the outer circle corresponds to the Ti phase. As a result of analyzing each phase by energy dispersive spectroscopy (EDS), the particle and matrix composition were Ti ₄₆ Y ₁₁ Al ₂₇ Co _{16 and} Y ₄₀ Ti ₁₅ Al ₂₂ Co ₂₃ , respectively.

Formation of Two Phase Amorphous Alloys

In the examples of the present invention, Ti and Y were selected based on immiscibility. The elements form intermetallic compounds or solid solutions, depending on the electron density at the negative electrode and Wigner-Seitz atomic cell boundaries. However, metals having electron densities obtained from common values of cell boundary densities do not mix with each other since their electron densities are not continuous.

4 is a binary state diagram of a Ti-Y alloy, which shows such incompatibility. As shown in the figure, miscibility gaps can be observed in the atomic region of Y from 30 to 80 or more at 1360 ° C. which is a liquid region. This indicates that when the atomic fraction of Y is 30 to 80, when the molten metal is cooled to 1545 ° C. or lower, it naturally separates while forming two liquid phases, which are divided into a Ti-rich phase and a Y-rich phase.

When the liquid phase is further cooled to 1355 ° C or less, the Ti-Y alloy is precipitated in the β-Ti phase and the α-Y phase without forming a compound or a solid solution. As shown in the state diagram of FIG. 4, the solubility value of Ti on α-Y and the solubility value of Y on β-Ti are very low. The values for the particles and the known composition depend on the solubility according to the cooling rate and the presence of additional elements such as Al and Co.

Electrochemical Properties of Pure Elements

5A and 5B are Pourbaix diagrams of Y and Ti, respectively. As shown in the figure, Y and Ti each exhibit unique electrochemical behavior.

Ti-Y-Al-Co alloys consist of two amorphous phases with different properties in terms of thermal stability, mechanical properties such as elastic modulus, physical properties such as thermal diffusivity, or chemical properties such as corrosion resistance. Corrosion resistance can be confirmed by the pH-potential graph.

Referring to FIG. 5A, when the applied potential E is low below −2.4 V, Y is not affected by the solution. However, if it is above -2.4 V and the pH value is acidically low, Y becomes yttrium ion (Y ⁺⁺⁺ ) dissolved in acid solution. If the pH value is above 6, Y (OH) ₃ oxide is formed.

Referring to FIG. 5B, Ti ⁺⁺ is formed when the potential is −1.8 to 0 V and the pH is low. However, when the potential is 0 to 2 V, Ti becomes a TiO ₂ oxide which is protected from corrosion regardless of pH. That is, since Y and Ti show different corrosion characteristics, when comparing FIGS. 5A and 5B, Y forms yttrium ions (Y) while forming an oxide film in which Ti is protected from corrosion at low pH and a potential of 0 to 2.2 V. ⁺⁺⁺ ). On the other hand, within a range of predetermined pH and potential, Al and Co become Al ₂ O ₃ or CoO oxides which are protected from corrosion, respectively.

Therefore, when Y and Ti are alloying elements, it is possible to selectively dissolve Y by appropriately adjusting the pH of the acidic solution. In this case, in order to remove Y from the Ti-Y-Al-Co alloy, it is preferable that the potential is 0 to 2 V and the pH is <6.

Electrochemical Properties of Alloy Ribbon

6 shows Ti ₅₆ Al ₂₄ Co ₂₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ in 0.1M HNO ₃ solution. Co ₂₀ ) ₆₅ and Y ₅₅ Al ₂₄ Co _{20 A potential potential} curve for an amorphous alloy ribbon.

In this experimental example, electropotential experiments were carried out in an electrochemical cell containing 0.1M HNO ₃ (pH = 1) electrolyte using ribbon samples of amorphous alloys as active electrodes and Ag / AgCl as reference electrodes.

As shown in FIG. 6, Ti ₅₆ Al ₂₄ Co ₂₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ , (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₆₅ and Y ₅₅ Al ₂₄ Co ₂₀ amorphous alloys exhibit distinct electrochemical behavior. Ti-Al-Co alloys exhibit broad passivation properties up to nearly 2.0V, while Y-Al-Co alloys do not exhibit passivation properties. This means that the Y-Al-Co alloy is corroded even under a voltage at which the Ti-Al-Co alloy does not corrode. This difference in electrochemical behavior is therefore suitable for selective corrosion.

6 shows the electrochemical behavior of the (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₆₅ alloy, which is a two-phase amorphous alloy. The critical potential (Ec) of these alloys is found between 1.75 V and between the critical potentials of the Y-Al-Co alloy and the Ti-Al-Co alloy.

Chemical selection corrosion

FIG. 7A is a SEM photograph of a powder prepared by selective corrosion of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ ribbons. FIG. FIG. 7B is an XRD graph after selective corrosion of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ ribbons. FIG. FIG. 7C is a TEM photograph and SAEDP photograph of a powder formed from (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ ribbons, and FIG. 7D is (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₆₅ TEM and SAEDP photographs of powders formed from ribbons.

In this experimental example, 100 mg of (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Ti ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) ribbon (α = 35, 50) was injected into 0.1M HNO ₃ solution. Applied. As shown in FIG. 7A, the powder is spherical in shape with a particle size of 20 nm to 200 nm. As shown in FIG. 7B or the result of XRD analysis of the low angle, the amorphous characteristics of the powder can be seen.

7C and 7D show TEM photographs of Ti-based powders at α = 35 and 50, respectively.

At this time, the powder extracted from the (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₃₅ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₆₅ ribbon has a slightly smaller particle size, it can be seen that the size of the powder can be adjusted by optimizing the composition of the alloy. In addition, as shown in FIGS. 7C and 7D, the amorphous properties of the powder can be confirmed from the SAEDP photograph of the powder.

Analysis of Amorphous Powder

FIG. 8 shows EDS analysis of Ti-based amorphous nanopowders obtained by selective corrosion of (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ amorphous alloys in a ribbon form. The composition of the powder can be seen by EDS analysis as well as XRD, SEM and TEM analysis.

It can be seen that the composition of the powder prepared from (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ ribbon is Ti _50.8 Co _29.5 Al _15.7 Y _4.0 , as shown in Table 1 below. The composition of Al and Co was almost unchanged, and the composition ratio of Ti was increased, while only Y was removed from the Y amorphous matrix.

 The solution after selective corrosion was analyzed to make sure the action of selective corrosion. The composition of the solution is as shown in Table 1. The solution showed high concentrations of Y, Al and Co as well as Ti. The presence of Ti shows that nano-sized particulate Ti particles are present in suspension in solution.

Partially selective corrosion

FIG. 9 is a SEM photograph showing that Ti alloy is attached to Y base by partially dissolving the (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ (Ti ₅₆ Al ₂₄ Co ₂₀ ) ₅₀ alloy.

As described above, Ti-based amorphous nanopowders can be obtained by a method of complete selective corrosion in which a two-phase amorphous alloy ribbon is immersed in a large volume of electrolyte for a long time. However, if the ribbon is immersed in a limited volume of electrolyte for only a short time, the selective corrosion will not proceed fully and only partial selective corrosion will occur. In this experimental example, only 30 minutes of selective corrosion was performed to select only the surface of the ribbon so as not to affect the center of the specimen.

 At this time, as shown in Figure 9 showing the microstructure of the surface, the chemical reaction is performed uniformly while forming a rough surface, although not constant. Moreover, since the electrolyte removes only the Y phase, Ti-based particles are observed on the surface of the ribbon. That is, the Y-rich phase can be removed from the surface by immersing a two-phase amorphous ribbon in an acid solution for a short time to form a spherical Ti nanoprotrusion having a large area on the surface. It can be used in a variety of applications, from in vivo to catalysts.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

The amorphous nanopowders according to the invention can be prepared by a method of selective corrosion which is very simple and easy to control.

In addition, the present invention is because the amorphous nano-powder is formed in the liquid phase can have a spherical and smooth surface, do not agglomerate the powder, it is possible to form a relatively small distribution of the size.

In addition, the present invention can control the size of the powder according to the initial composition. That is, the structure of the amorphous powder can be confirmed by the initial state of the alloy.

In addition, the present invention can perform selective corrosion for a short time to form spherical Ti-based nanoprojections having a large area on the surface.

Claims (15)

_{Represented by the} formula Ti _100-abcd Al _a Co _b Y _c I _d , wherein a, b, c and d are 10% a≤30, 10≤b≤30, and 1≤c≤10 in atomic%, respectively. And 0.1 ≦ d ≦ 5, wherein I is an impurity Ti-based amorphous nanopowder. According to claim 1, The Ti-based amorphous powder is represented by the formula (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) , wherein α is from a two-phase amorphous alloy having 30 ≦ α ≦ 50 in atomic%. Ti-based amorphous nano powder formed. The method of claim 2, The two-phase amorphous alloy has a thickness of 5 μm to 50 μm and a width of 1 mm to 10 mm in the form of a ribbon (ribbon) of Ti-based amorphous nanopowder. According to claim 1, The Ti-based amorphous nano powder is a Ti-based amorphous nano powder formed by the selective corrosion of the two-phase amorphous alloy. The method of claim 4, wherein The selective corrosion is Ti-based amorphous nano-powder made in HNO ₃ solution. The method of claim 4, wherein The active electrode at the time of selective corrosion is Ti-based amorphous nano-powder of the two-phase amorphous alloy. According to claim 1, The amorphous powder is a spherical Ti-based amorphous nano powder According to claim 1, The Ti-based amorphous nano powder is a Ti-based amorphous nano powder having a size of 20nm to 200nm. As a method of manufacturing a Ti-based amorphous nano powder according to claim 1, Melting and mixing Ti, Y, Al, Co and other impurities; Cooling the molten metal to form a two-phase amorphous alloy; And Removing the continuous matrix of the two-phase amorphous alloy by selective corrosion to form an amorphous powder Method for producing a Ti-based amorphous nano powder comprising a. The method of claim 9, The Ti-based amorphous nano powder is represented by the formula (Ti ₅₆ Al ₂₄ Co ₂₀ ) _α (Y ₅₆ Al ₂₄ Co ₂₀ ) _(100-α) , wherein α is a two-phase amorphous alloy having an atomic ratio of 30 ≦ α ≦ 50. Method for producing Ti-based amorphous nano powder formed from. The method of claim 10, The two-phase amorphous alloy has a thickness of 5㎛ to 50㎛, 1mm to 10mm in the form of a ribbon (ribbon) in the form of a Ti-based amorphous nano powder manufacturing method. The method of claim 9, The selective corrosion is a method for producing a Ti-based amorphous nano-powder made in HNO ₃ solution. The method of claim 12, A method of manufacturing Ti-based amorphous nanopowder using the two-phase amorphous alloy as the active electrode during the selective corrosion. The method of claim 9, The amorphous powder is a method for producing a Ti-based amorphous nano powder is formed in a spherical shape. The method of claim 9, The Ti-based amorphous nanopowder is a method for producing a Ti-based amorphous nanopowder having a size of 20nm to 200nm.

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