KR100486889B1 - Method for manufacturing ZnMgO alloy powder by the mechanical alloying - Google Patents

Abstract

The present invention relates to a method for producing a ZnMgO alloy powder by mechanical alloying.

    In the production method according to the present invention, the ZnO powder and the MgO powder are mixed so that the number-of-moles ratio of each molecule is 9.99: 0.01-7: 3, mechanically alloyed with a ball mill, and then the ZnMgO alloy powder obtained at this time is 500-600 ° C. Heat treatment in an oxygen atmosphere.

According to the present invention, unlike the conventional film deposition method, ZnMgO, which can be used in a light emitting device, a light receiving device, or an electronic device operating in the ultraviolet region, can be alloyed very simply and inexpensively.

Description

    Method for manufacturing ZnMgO alloy powder by mechanical alloying {Method for manufacturing ZnMgO alloy powder by the mechanical alloying}

 The present invention relates to a method for producing a ZnMgO alloy powder, and more particularly to a method for synthesizing ZnMgO powder using a ball mill which is a mechanical alloying method of ZnO and MgO powder.

In recent years, there has been a strong demand for the realization of a semiconductor light emitting element having a wavelength in the blue light to ultraviolet light, from the demand for the development of multicoloring in a light emitting display and the improvement of the data density in data communication and data recording. It is becoming. As a material for forming a semiconductor light emitting element capable of emitting blue light, a GaN-based semiconductor material may be mentioned. However, in addition to the problems in the manufacturing process that it is difficult to grow the crystal of the gallium nitride compound semiconductor, it is difficult to obtain continuous light emission and has the disadvantage of being expensive. Therefore, research into ZnO having a wavelength in the blue light to ultraviolet light region is actively conducted as a semiconductor material to replace it. In the case of ZnO, not only is it suitable as a material for blue light emission or shorter wavelength light emission because it has similar characteristics to GaN in the band gap and crystal structure, and it is an exciton bonding that is about three times (eg, 60 meV) GaN. Since it has energy (Exciton binding energy), it is considered to be a very suitable material as a material material for the next generation of short wavelength optical devices. In particular, the alloy of ZnO and MgO or CdO has the advantage that the band gap can be adjusted in the range of 2.8 ~ 4eV. Conventional ZnMgO synthesis method is known a method of alloying in the form of a film using sputtering or pulsed laser deposition, the pulsed laser deposition method is KrF laser under high pressure of about 10 ^-7 Torr Refers to a method for synthesizing a ZnMgO thin film using. However, it is difficult to make a thick film or to make a bulk ZnMgO by this method, and when the film is thin, it is difficult to recombine electron-hole pairs inside the film, and thus it is difficult to emit enough light, resulting in low luminous efficiency. There is a disadvantage in that it loses, and there is a problem in that the light receiving efficiency is low because it is difficult to generate such an electron-hole pair in the light receiving device. In addition, the ZnMgO alloy may be produced by the melting method, but the melting point of ZnO and MgO is 1975 and 2826 ° C., respectively, so that the synthesis is not easy.

Therefore, the first technical problem to be achieved by the present invention is to provide a method for producing a simple and inexpensive ZnMgO alloy powder difficult to synthesize in the prior art.

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The present invention to achieve the first technical problem

       (a) mixing the ZnO powder and the MgO powder such that the mole ratio of each molecule is 9.99: 0.01 to 7: 3;

       (b) injecting the mixed powder with a ball into a container, and then putting the mixed powder into a ball mill device to obtain a ZnMgO alloy powder by ball milling in an argon gas atmosphere;

       (c) provides a method for producing a ZnMgO alloy powder, comprising the step of heat-treating the ZnMgO alloy powder in an oxygen atmosphere of 500 ~ 600 ℃.

       According to one embodiment of the invention, the weight ratio of the mixed powder and the ball is preferably 1:16.

       According to another embodiment of the present invention, the ball milling time is preferably 20 hours or more.

        Moreover, it is preferable that the said heat processing time is 3 to 15 hours.

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 Hereinafter, the present invention will be described in detail.

       Mechanical Alloying (MA) process is the process of obtaining special alloy powders by stirring or ball milling elemental powders or alloyed powders of alloys together with hard balls (or steel balls) with high mechanical energy. Say fair. As the term itself says, it originally refers to the process of making alloy powder by mechanical method only at room temperature without dissolving metal, but even if no alloy is formed, high-energy dry ball milling of metal powder is collectively called mechanical alloying. . In general, the mechanical alloying process can be classified into an initial particle growth step, a medium-term particle breaking step, and a final steady state fine powder forming step according to the powder shape change during ball milling. Invented by INCO in the late 1960s, the process was recognized as an ideal method for producing an oxide-disperse high-temperature alloy. In recent years, it has been widely used to develop special-purpose high-temperature steel materials, intermetallic compounds, and semi-equilibrium alloys.

       In general, the mechanical alloying process is classified into three stages according to the change of powder shape. First, in the initial stage, the constituent powders are coarsened by predominantly cold welding due to repeated collisions between the balls. At this time, the cross-sectional structure of the powder shows that the elementary powders have a layered structure, but atomic mixing, that is, alloying, is not performed. In the next intermediate step, the coarse particles undergo continuous work hardening. In this case, the powder is not alloyed but the powder components are very finely mixed. The last stage is a steady-state stage in which only fine particles of several tens to several micrometers in size have a uniform particle size distribution, and mechanical alloying is completed.

        In the present invention, ZnO powder and MgO powder is mixed so that the mole ratio of each molecule is 9.99: 0.01-7: 3, when the molar ratio of ZnO and MgO molecules is less than 9.99: 0.01, it is difficult to achieve the effect of alloying and 7: 3 In the case where the MgO is exceeded, Mg is substituted at the Zn site of ZnO to form a metastable state, which is not preferable. Next, the mixture is placed in a stainless steel container together with a stainless steel ball or alumina ball, and a ZnMgO alloy powder is prepared by using a ball mill. The mechanical alloying according to the present invention may use various ball mills such as attritors, planetary ball mills, vibratory ball mills, horizontal ball mills, and the like. At this time, the weight ratio of the ball and the powder is 16: 1, if there is a problem that the ball mill is not made smoothly out of this weight ratio. The mechanical alloying time was set to 20 hours or more, but ball milling of 20 hours or less is not preferable because the particles are not sufficiently pressed and fractured and mechanical alloying is not sufficient. Next, since the mechanically alloyed powder has a fairly unstable crystal state while undergoing mechanical alloying for a long time, it is necessary to stabilize the powder through heat treatment. Therefore, heat treatment was performed in an oxygen atmosphere at 500 to 600 ° C., and the heat treatment time was 3 to 15 hours. When only the ball mill process is performed without such heat treatment, as shown in FIGS. 2 and 3, since the ZnMgO alloying is not performed, it is in an amorphous state. When the heat treatment temperature is less than 500 ° C., it is not preferable because sufficient heat energy may not be supplied and thus remains in an amorphous state, and when the heat treatment temperature is high, a phase may change. In addition, as can be seen in Figures 2 and 3 alloying is achieved only when the heat treatment time is 3 hours or more, and if more than 15 hours the alloying is all progressed even if the heat treatment any more does not occur.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited thereto.

Example 1

       ZnO powder (purity: 99.995%, particle size: -200 mesh, manufactured by Cerac, USA) 82.5% by weight, MgO powder (purity: 99.5%, particle size: -325 mesh, manufactured by Cerac, USA) mixed 17.5% by weight Then, the stainless steel ball (1/4 inch diameter) was put into a stainless steel container and milled using a SPEX 8000M mixer / mill made by SPEX. The weight ratio of the stainless steel ball and the powder was 16: 1 and the milling time was 20 hours. Next, ZnMgO alloy powder was obtained by heat treatment at 600 ° C. in an oxygen atmosphere (gas flow rate: 300 sccm) for 3 hours.

       Example 2

       A ZnMgO alloy powder was prepared in the same manner as in Example 1, except that the last heat treatment time was 9 hours.

       Example 3

       A ZnMgO alloy powder was prepared in the same manner as in Example 1, except that the last heat treatment time was 15 hours.

       X-ray diffractometer (Rigaku D / Max-IIA X-ray X-ray diffractometer, CuKαradiation: λ = 1.5418Å) and neutron diffraction apparatus for the synthesized powder synthesized by the above method and heat treated powder The crystal structure of the powder was analyzed using the Atomic Reactor-Hanaro, λ = 1.835 kW).

       2 is an X-ray diffraction test result of the ZnMgO alloy powder prepared in Examples 1 to 3. After mechanical alloying, it can be seen that a powder 10 having a phase different from that of ZnO or MgO is formed. As the heat treatment progressed, peaks that were not found after mechanical alloying appeared. Among these peaks, the peaks of ZnMgO alloys appeared at points 2θ of 29.974 ° (14) and 35.371 ° (15), respectively.The peaks by the (100) plane and the (002) plane of the ZnO alloy were MgO and Will move to achieve.

 3 is a neutron diffraction test result for the powder prepared by the present invention. The experimental results consist of peaks from ZnO, MgO and ZnMgO alloys. Among them, peaks corresponding to ZnMgO alloys appeared at points 2θ of 35.828 ° (14) and 42.341 ° (15). These are peaks corresponding to the (100) plane, the (002) plane, and the (200) plane of ZnO while being alloyed with MgO. Since the neutron diffraction experiment uses a neutron beam of λ = 1.835 Å, the peak position is different from that of the X-ray diffraction experiment. And since it has a relatively long penetration depth compared to X-rays, the results on the inside of the material can be known. First, the peak at 2θ of 35.828 ° is the peak (38.054 °) represented by the (100) plane of ZnO when alloyed with MgO. That is, while the peak by the ZnO (100) plane whose 2θ is 38.054 ° forms an alloy, it moves to the point where 2θ is 35.828 °. Through this, it can be seen that the a value of ZnO increases from 3.250 kPa to 3.444 kPa after mechanical alloying is performed. In other words, the alloy is expanded by 0.194Å in the a-axis direction, which is consistent with the result obtained by the X-ray diffraction experiment. Therefore, it can be seen that the ZnMgO alloy powder can be synthesized by the manufacturing method according to the present invention. When the ZnMgO alloy powder prepared according to the present invention is used in an actual electronic device or the like, it is used in the form of a film through a method such as hot pressing.

According to the present invention, ZnMgO, which can be used in light emitting devices, light receiving devices, or electronic devices operating in the ultraviolet region, can be alloyed by a very simple method unlike the conventional film deposition method, and thus has an advantage in terms of productivity and economy. have.

      1 is a schematic diagram of ZnO hexagonal structure and MgO NaCl structure in which Zn is replaced by Mg in a hexagonal structure of ZnO by a ball mill, thereby forming a ZnMgO alloy.

      2 is an X-ray diffraction (XRD) showing the formation of ZnMgO alloy according to the present invention.

    Figure 3 is a neutron diffraction (Neutron diffraction: ND) showing the formation of ZnMgO alloy according to the present invention.

<Explanation of symbols for the main parts of the drawings>

1: Zn atom in ZnO

2: O atom in ZnO

3: ZnO of hexagonal structure

4: O atom in MgO

5: Mg atom in MgO

6: MgO of NaCl structure

7: ZnMgO alloy of hexagonal structure

8: XRD of ZnO Powder

9. XRD of MgO Powder

10. XRD of ZnMgO alloy powder after ball milling for 20 hours

11: XRD of ZnMgO alloy powder prepared by Example 1

12: XRD of the ZnMgO alloy powder prepared by Example 2

13: XRD of ZnMgO Alloy Powder Prepared by Example 3

14: (100) Peak of ZnMgO Alloy Powder

15: (002) peak of ZnMgO alloy powder

16: ND of ZnO powder

17.ND of MgO Powder

18.ND of ZnMgO Alloy Powders after 20 Hour Ball Milling

19: ND of ZnMgO alloy powder prepared by Example 1

20: ND of ZnMgO alloy powder prepared by Example 2

21: ND of ZnMgO Alloy Powder Prepared by Example 3

Claims (5)

 (a) mixing the ZnO powder and the MgO powder such that the mole ratio of each molecule is 9.99: 0.01 to 7: 3;        (b) injecting the mixed powder with a ball into a container, and putting the mixed powder into a ball mill, and then ball milling in an argon gas atmosphere to obtain a ZnMgO alloy powder;        (c) ZnMgO alloy powder manufacturing method comprising the step of heat-treating the ZnMgO alloy powder in an oxygen atmosphere of 500 ~ 600 ℃. The method of claim 1, wherein the weight ratio of the mixed powder to the ball is 1:16.      The method of claim 1, wherein the ball milling time is 20 hours or more.       The method for producing a ZnMgO alloy powder according to claim 1, wherein the heat treatment time is 3 to 15 hours. delete