KR100812798B1 - Method of manufacturing magnesium di-boride superconducting powder - Google Patents

Method of manufacturing magnesium di-boride superconducting powder Download PDF

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KR100812798B1
KR100812798B1 KR1020060138373A KR20060138373A KR100812798B1 KR 100812798 B1 KR100812798 B1 KR 100812798B1 KR 1020060138373 A KR1020060138373 A KR 1020060138373A KR 20060138373 A KR20060138373 A KR 20060138373A KR 100812798 B1 KR100812798 B1 KR 100812798B1
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magnesium
aqueous solution
superconducting
powder
magnesium diboride
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고재웅
유재무
김영국
정국채
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한국기계연구원
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    • CCHEMISTRY; METALLURGY
    • C01INORGANIC CHEMISTRY
    • C01BNON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B35/00Boron; Compounds thereof
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    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/58Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01INORGANIC CHEMISTRY
    • C01PINDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
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    • C01P2004/60Particles characterised by their size
    • C01P2004/64Nanometer sized, i.e. from 1-100 nanometer
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Abstract

A method of preparing a superconducting magnesium diboride powder is provided to produce a wire having high critical current density by increasing the number of grain boundaries that can fixate magnetic flux, increase the number of filaments during manufacturing of a superconducting multi-core wire, increase mechanical processing characteristics of a superconducting magnesium diboride wire, and increase engineering critical current density of the superconducting magnesium diboride wire. A method of preparing a superconducting magnesium diboride powder includes the steps of: mixing 2 moles of an aqueous boracic acid solution with 1.0 to 1.5 mole of an aqueous solution comprising magnesium metal ions, and heating and stirring the mixed solution at 25 to 100 deg.C for 0.5 to 10 hours to prepare an aqueous solution in which magnesium and boracic acid metal ions are mixed; adding ethyl alcohol to the aqueous solution to prepare a precursor solution having a concentration of 0.05 to 2.0 mol/L; and spraying the precursor solution by a spray and heat-treating the sprayed precursor solution in a thermal reactor to prepare a superconducting powder, wherein the aqueous solution comprising magnesium metal ions is one selected from magnesium nitrate, magnesium acetate, and magnesium citrate. The aqueous solution preparing step includes the process of additionally adding a nano-sized SiC fine powder for performing a magnetic flux-fixating function into the aqueous solution and stirring the mixture.

Description

마그네슘 다이보라이드 초전도 분말 제조방법{Method of manufacturing magnesium di-boride superconducting powder}Method for manufacturing magnesium di-boride superconducting powder

도 1은 본 발명에 따른 마그네슘 다이보라이드 초전도 분말 제조에 사용되는 장치의 예시적인 구성도,1 is an exemplary configuration diagram of an apparatus used for manufacturing magnesium diboride superconducting powder according to the present invention;

도 2는 본 발명에 따라 제조된 마그네슘 다이보라이드 초전도 분말 입자를 주사전자현미경으로 관찰한 사진,Figure 2 is a photograph of a magnesium diboride superconducting powder particles prepared according to the present invention by scanning electron microscope,

도 3은 본 발명에 따라 제조된 마그네슘 다이보라이드 초전도 분말의 X-선 회절 분석 결과 그래프,3 is a graph showing the results of X-ray diffraction analysis of magnesium diboride superconducting powder prepared according to the present invention,

도 4는 본 발명에 따른 초전도 분말과 기존재의 자장하에서 임계전류 특성 결과 그래프.Figure 4 is a graph of the results of the critical current characteristics under the magnetic field of the superconducting powder and the existing material according to the present invention.

♧ 도면의 주요 부분에 대한 부호의 설명 ♧♧ description of the symbols for the main parts of the drawing ♧

10....전구체 용액 저장조 12....초음파진동자10 .... precursor solution reservoir 12 .... ultrasonic vibrator

14....분무관 20....냉각조14 .... Atomizer 20 .... Cooling Tank

30....반응기 32....가열수단30. Reactor 32. Heating means

40....컬렉터40 .... collector

본 발명은 마그네슘 다이보라이드 초전도 분말 제조방법에 관한 것이다.The present invention relates to a method for producing magnesium diboride superconducting powder.

일반적으로, 마그네슘 다이보라이드 초전도체는 액체 헬륨온도에서 작동하는 금속계 저온 초전도체에 비해 상용 냉동기를 이용하여 냉각 가능한 온도인 39K라는 상당히 높은 임계온도를 가지고, 원료의 가격이 저렴하며, 비등방성이 적고 긴 가간섭성 길이(coherence length)를 갖고, 전류 통전에 결정립들의 배열이 요구되지 않을 뿐만 아니라 결정립들간의 접촉부분에서도 충분히 대전류를 흘릴 수 있는 특성이 있다.In general, magnesium diboride superconductor has a considerably higher critical temperature of 39K, which is a temperature that can be cooled by using a commercial freezer, compared to a metal-based low temperature superconductor operating at liquid helium temperature. It has a coherence length, not only does not require an array of grains to carry current, but also has a characteristic that a large current can flow sufficiently in the contact portion between the grains.

따라서, 지금까지 알려진 자장 하에서의 특성열화가 비교적 심한 단점만 보완된다면, 20K, 5T이하의 자장 하에서 운전 가능한 전력응용기기에의 도체로의 적용에 큰 기대를 갖게 하는 재료로 특히 의료용 MRI의 도체재료로 각광받을 수 있을 것이다.Therefore, if the deterioration of characteristics under the magnetic field known to the present is only compensated for the relatively severe disadvantages, it is a material that has great expectations for the application of the conductor to a power application device that can operate under a magnetic field of 20K or less than 5T, especially as a conductive material for medical MRI. You'll be in the spotlight.

이때, 자장 하에서 특성열화의 원인으로는 재료자체의 이방성과 전류를 흘렸을 때 로렌츠힘(Lorentz force)에 의해 발생하는 자속선(flux line)들의 요동으로부터 발생하는 손실 등을 들 수 있다.At this time, the cause of the deterioration of characteristics under the magnetic field may include loss caused by fluctuations of flux lines generated by Lorentz force when anisotropy of the material itself and current flows.

이런 자속선들의 요동들은 자속선을 포획하여 고정시켜 줄 수 있는 고정점(pinning site)을 도입함에 의해 이로부터 발생하는 손실을 억제 할 수 있다.These fluctuations of magnetic flux lines can suppress the loss from this by introducing a pinning site that can capture and fix the magnetic flux lines.

특히, 마그네슘 다이보라이드 초전도체에서는 고정점 역할을 입계가 할 수 있는 것으로 알려 져 있고, 나아가 마그네슘 다이보라이드 초전도체는 고온 초전도체들에 비해 이방성이 심하지 않고 가간섭성 길이(coherence length)도 긴 반면, 먼저 언급한 바와 같이, 결정립들간의 접촉부분에서도 충분히 대전류를 흘릴 수 있기 때문에 마그네슘 다이보라이드 초전도체 분말을 나노크기로 제조하여 마그네슘 다이보라이드 초전도체선재에 자속고정점으로 이용가능한 입계의 숫자를 늘릴 수 있을 것으로 기대된다.In particular, the magnesium diboride superconductor is known to have a grain boundary role, and furthermore, the magnesium diboride superconductor is less anisotropic than the high temperature superconductors and has a longer coherence length. As mentioned earlier, large currents can flow even in the contact areas between the grains, thus making magnesium diboride superconductor powders nanoscale to increase the number of grain boundaries available as magnetic flux anchor points for magnesium diboride superconductor wires. It is expected to be.

그러나, 현재 상업적으로 생산되고 있는 마그네슘 다이보라이드 초전도 분말은 B 분말과 Mg 분말을 MgO 코팅된 Fe 용기 내에서 수소기체를 흘리면서 800℃로 가열하는 방법이 사용되고 있어 분말의 크기 및 형상 제어가 쉽지 않고, 제조 조건이 매우 가혹하기 때문에 제조된 분말의 크기가 조대하고 입자가 균일하지 못한 단점을 가진다.However, the commercially produced magnesium diboride superconducting powder is a method of heating the B powder and Mg powder to 800 ℃ while flowing hydrogen gas in MgO-coated Fe container is difficult to control the size and shape of the powder However, since the manufacturing conditions are very harsh, the size of the powder produced is coarse and the particles are not uniform.

본 발명은 상술한 바와 같은 종래 기술상의 한계성을 감안하여 이를 해결하고자 창출한 것으로, 전구체 용액을 제조하고 이를 분무하여 열반응 및 환원 열처리에 의해 구형의 수십나노 크기에서부터 수마이크론 크기의 미세한 마그네슘 다이보라이드 분말을 제조할 수 있도록 함으로써 자속 고정 특성역할을 할 수 있는 입계의 숫자를 늘려 높은 임계전류밀도를 갖는 선재를 생산할 수 있도록 한 마그네슘 다이보라이드 초전도 분말 제조방법을 제공함에 그 주된 목적이 있다.The present invention has been made in view of the limitations of the prior art as described above, to solve this problem, by preparing a precursor solution and spraying it, by the thermal reaction and reduction heat treatment, a fine magnesium dibo from the size of several tens of nanometers to several microns The main object of the present invention is to provide a method for producing magnesium diboride superconducting powder, which enables the production of wire powder having a high critical current density by increasing the number of grain boundaries that can act as a flux-fixing property by allowing the manufacture of a ride powder.

또한, 본 발명은 기존의 방법에 비해 입자크기가 작고 높은 순도를 유지할 수 있을 뿐 아니라 구형의 형상을 가지기 때문에 다심 초전도 선재 제조시 필라멘트 수를 늘릴 수 있으며, 필라멘트 크기를 줄일 수 있기 때문에 마그네슘 다이보라이드 초전도 선재의 기계가공 특성을 높일 수 있고, 초전도 충진율을 높여 공학적 임계전류밀도(engineering critical current density)값을 높일 수 있도록 한 마그네슘 다이보라이드 초전도 분말 제조방법을 제공함에도 그 목적이 있다.In addition, the present invention can not only maintain a high particle size and high purity compared to the conventional method, but also has a spherical shape, so that the number of filaments can be increased when manufacturing multi-core superconducting wires, and the size of the filaments can be reduced. It is also an object of the present invention to provide a method for manufacturing magnesium diboride superconducting powder which can increase the machining characteristics of the rod superconducting wire and increase the engineering critical current density by increasing the superconducting filling rate.

본 발명은 상기한 기술적 과제를 달성하기 위하여, 마그네슘 금속이온을 포함하는 수용액 1.0~1.5몰에 붕산 수용액 2몰을 혼합하고 이를 가열 및 교반시켜 마그네슘과 붕산 금속이온이 혼합된 수용액을 제조하는 단계와; 상기 수용액에 에칠알콜을 첨가하여 0.05~2.0mol/L 농도의 전구체 용액을 제조하는 단계와; 상기 전구체 용액을 분무장치를 이용하여 분무시킨 후 열반응장치의 반응기 내에서 열처리하여 초전도 분말을 제조하는 단계로 이루어진 마그네슘 다이보라이드 초전도 분말 제조방법을 제공한다.The present invention to achieve the above technical problem, by mixing 2 mol of boric acid aqueous solution to 1.0 ~ 1.5 mol aqueous solution containing magnesium metal ions and heating and stirring it to prepare an aqueous solution mixed with magnesium and boric acid metal ion; ; Adding ethanol to the aqueous solution to prepare a precursor solution having a concentration of 0.05 to 2.0 mol / L; It provides a method for producing magnesium diboride superconducting powder consisting of the step of spraying the precursor solution using a spray device and then heat-treating in a reactor of a thermal reactor to produce a superconducting powder.

이때, 상기 마그네슘 금속이온을 포함하는 수용액은 질산마그네슘, 초산마그네슘, 구연산마그네슘 중에서 선택된 하나인 것에도 그 특징이 있다.At this time, the aqueous solution containing the magnesium metal ion is characterized in that the one selected from magnesium nitrate, magnesium acetate, magnesium citrate.

또한, 상기 수용액 제조단계에서 가열 및 교반은 25~100℃에서 0.5~10시간 동안 수행하는 것에도 그 특징이 있다.In addition, the heating and stirring in the aqueous solution manufacturing step is characterized in that it is carried out for 0.5 to 10 hours at 25 ~ 100 ℃.

뿐만 아니라, 상기 열반응장치의 반응기 내에서 이루어지는 열처리는 비산화성 분위기로 600~900℃의 온도에서 행해지는 것에도 그 특징이 있다.In addition, the heat treatment performed in the reactor of the thermal reactor is characterized in that it is carried out at a temperature of 600 ~ 900 ℃ in a non-oxidizing atmosphere.

아울러, 상기 수용액 제조단계에서 수용액에 자속 고정 역할을 하는 나노크기의 SiC 미분체를 더 첨가하여 함께 교반되는 것에도 그 특징이 있다.In addition, it is also characterized in that the addition of the nano-size SiC fine powder to the magnetic flux fixing role in the aqueous solution manufacturing step and stirred together.

이하에서는, 첨부도면을 참고하여 본 발명에 따른 바람직한 실시예를 보다 상세하게 설명하기로 한다.Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

도 1은 본 발명에 따른 마그네슘 다이보라이드 초전도 분말 제조에 사용되는 장치의 예시적인 구성도이고, 도 2는 본 발명에 따라 제조된 마그네슘 다이보라이드 초전도 분말 입자를 주사전자현미경으로 관찰한 사진이며, 도 3은 본 발명에 따라 제조된 마그네슘 다이보라이드 초전도 분말의 X-선 회절 분석 결과 그래프이고, 도 4는 본 발명에 따른 초전도 분말과 기존재의 자장하에서 임계전류 특성 결과 그래프이다.1 is an exemplary configuration diagram of a device used for preparing magnesium diboride superconducting powder according to the present invention, Figure 2 is a photograph of a magnesium diboride superconducting powder particles prepared according to the present invention observed with a scanning electron microscope 3 is a graph showing the results of X-ray diffraction analysis of the magnesium diboride superconducting powder prepared according to the present invention, and FIG. 4 is a graph showing the results of the critical current characteristics under the magnetic field of the superconducting powder and the conventional material according to the present invention.

먼저, 본 발명에서 제시하는 마그네슘 다이보라이드 초전도 분말 제조방법은 다음과 같은 단계를 통해 제조된다.First, the magnesium diboride superconducting powder manufacturing method proposed in the present invention is prepared through the following steps.

[수용액 제조단계][Aqueous solution preparation step]

본 발명 제조방법에 포함된 전구용액 제조단계는 질산 마그네슘, 초산 마그네슘, 구연산 마그네슘 등 마그네슘 금속이온을 포함하는 수용액 1.0~1.5몰에 붕산 수용액 2몰을 혼합하여 25~100℃ 온도에서 0.5~10 시간 동안 반응시켜 마그네슘과 붕소 금속이온이 혼합된 수용액을 제조한다.The precursor solution preparation step included in the preparation method of the present invention mixes 2 mol of boric acid solution in 1.0-1.5 mol of an aqueous solution containing magnesium metal ions such as magnesium nitrate, magnesium acetate and magnesium citrate for 0.5 to 10 hours at a temperature of 25 to 100 ° C. By reacting to prepare an aqueous solution in which magnesium and boron metal ions are mixed.

이때, 상기 수용액에 자속 고정 역할을 할 수 있는 나노크기의 SiC 미분체를 첨가하여 함께 교반할 수 있다.At this time, the nano-size SiC fine powder, which may play a role of fixing the magnetic flux, may be added and stirred together.

여기에서, 혼합비율, 즉 몰비는 마그네슘의 높은 증기압을 고려하여 마그네슘이온이 어느 정도 과량으로 존재하게끔 고려하였고, 온도와 반응시간은 마그네슘 금속이온과 붕소를 포함하는 염의 물에 대한 용해도를 고려하여 결정하였다.Here, the mixing ratio, that is, the molar ratio is considered to be present in some excess magnesium ions in consideration of the high vapor pressure of magnesium, temperature and reaction time is determined in consideration of the solubility of the salt containing magnesium metal ions and boron in water It was.

또한, 온도의 경우 25℃ 이하에서는 금속이온염들의 용해도가 너무 떨어져서 반응시간이 10시간 이상 소요되어 경제성이 떨어지며, 온도가 올라감에 따라 용해 도는 증가하나 사용되어진 염 수용액의 증기압도 증가하여 증발되기 때문에 온도와 반응시간은 상기 조건으로 결정하였다.In addition, in case of temperature, the solubility of metal ion salts is so low that the reaction time takes 10 hours or more and economic efficiency is lowered. As the temperature increases, the solubility increases but the vapor pressure of the used aqueous salt solution also increases and evaporates. Temperature and reaction time were determined under the above conditions.

[전구체용액 제조단계][Preparation solution manufacturing step]

상기와 같이 제조된 수용액에 에칠알콜을 첨가하여 0.05~2.0 mol/L 농도의 전구체 용액을 제조한다.Ethyl alcohol is added to the aqueous solution prepared as described above to prepare a precursor solution of 0.05 ~ 2.0 mol / L concentration.

이때, 0.05mol/L 농도 이하에서는 입자크기가 작아지지만 수율이 떨어져 경제성이 현저히 나빠지고, 2.0mol/L 농도 이상에서는 입자크기가 십마이크론을 넘어가며 입도분포가 불균일하여지므로 상기 범위의 농도로 한정함이 바람직하다.At this time, the particle size becomes smaller at 0.05 mol / L or lower, but the yield is significantly lower, and the economic efficiency is remarkably worse. At 2.0 mol / L or higher, the particle size exceeds 10 microns and the particle size distribution becomes uneven, so it is limited to the concentration in the above range. It is preferable to.

[초전도분말 제조단계][Superconductive Powder Manufacturing Step]

이렇게 하여, 전구체 용액이 제조되면, 상기 전구체 용액을 분무장치를 이용하여 분무시킨 후 열반응장치내에서 열처리하여 마그네슘 다이보라이드 초전도분말을 제조한다.In this way, when the precursor solution is prepared, the precursor solution is sprayed using a spray apparatus, and then heat-treated in a thermal reactor to prepare magnesium diboride superconducting powder.

상기 분무장치는 초음파 분무장치, 이류체 노즐 분무장치 등이 사용될 수 있다.The spray device may be an ultrasonic spray device, an air atomizer spray device, or the like.

이를 테면, 상기 초음파 분무장치는 도 1의 예시와 같이, 초음파진동자(12)가 내장된 전구체 용액 저장조(10)와, 이를 냉각하는 냉각조(20)와, 상기 전구체 용액 저장조(10)의 상단에 배관된 분무관(14) 및 캐리어가스 연결관(16)으로 구성된다.For example, the ultrasonic atomizer is, as shown in Figure 1, the precursor solution reservoir 10 in which the ultrasonic vibrator 12 is embedded, the cooling tank 20 for cooling it, and the top of the precursor solution reservoir 10 It consists of a spray pipe 14 and a carrier gas connecting pipe 16 piped in the.

이때, 상기 분무관(14)의 단부는 석영 튜브의 일종인 반응기(30)로 연결되고, 상기 반응기(30)의 하부에는 분말화된 초전도분말(40)을 포집하기 위한 컬렉 터(40)가 연결된다.At this time, the end of the spray tube 14 is connected to the reactor 30 is a kind of quartz tube, the lower portion of the reactor 30, the collector 40 for collecting the powdered superconducting powder 40 is Connected.

그리하여, 상기 초음파진동자(12)의 진동에 의해 생성된 전구체 용액 액적은 분무관(14)을 타고 고온의 반응기(30) 내부로 분무되게 된다.Thus, the precursor solution droplets generated by the vibration of the ultrasonic vibrator 12 are sprayed into the high temperature reactor 30 by the spray tube 14.

이 과정에서, 상기 반응기(30)는 그 내부가 비산화성 분위기로 유지되고 있고, 또 가열수단(32)에 의해 대략 600~900℃ 정도로 유지되고 있으므로 이 온도범위에서 열처리되게 된다.In this process, the reactor 30 is maintained in a non-oxidizing atmosphere, and is maintained at about 600 ~ 900 ℃ by the heating means 32 is to be heat treated in this temperature range.

상기 액적은 열처리되면서 마그네슘 다이보라이드 초전도 분말로 분말화되게 되고, 분말상의 물질은 낙하되어 컬렉터(40)로 수집되게 된다.The droplets are powdered into magnesium diboride superconducting powder while being heat treated, and the powdery material is dropped and collected by the collector 40.

여기에서, 상기 반응기(30) 내부온도를 상기와 같이 한정하는 이유는 600℃이하가 되면 미반응 물이 존재하고, 900℃ 이상이 되면 마그네슘 다이보라이드상이 불안정하여 마그네시아나 다른 2차상들이 존재하게 되므로 이를 한정함이 바람직하다.Here, the reason for limiting the internal temperature of the reactor 30 as described above is that unreacted water is present at 600 ° C. or lower, and magnesium diboride phase is unstable at 900 ° C. or higher so that magnesia or other secondary phases exist. It is therefore desirable to limit this.

상기와 같은 방법으로 제조된 마그네슘 다이보라이드 초전도 분말은 종래 방법에 비해 입자크기를 전구 용액 농도, 반응온도, 이송가스의 속도 등에 의해 나노 크기로부터 마이크론 크기까지 다양하게 얻을 수 있기 때문에 마그네슘 다이보라이드 초전도 분말의 용도에 맞게 활용이 가능하며, 특히 나노 크기의 경우 자속 고정 특성역할을 할 수 있는 입계의 숫자를 늘려 줄 수 있기 때문에 자장하에서 높은 임계전류밀도를 갖는 초전도 선재의 제조가 가능하다.Magnesium diboride superconducting powder prepared by the method described above is a magnesium diboride because the particle size can be obtained from nano size to micron size by precursor solution concentration, reaction temperature, transport gas speed, etc. The superconducting powder can be used according to the use, and especially in the case of nano size, it is possible to increase the number of grain boundaries that can act as a magnetic flux fixing property, thereby making it possible to manufacture a superconducting wire having a high critical current density under a magnetic field.

이하, 본 발명에 따른 실시예를 설명한다.Hereinafter, embodiments according to the present invention will be described.

[실시예]EXAMPLE

본 실시예는 본 발명의 상세한 설명을 위한 가장 바람직한 모델을 제시한 것일 뿐 이것에 의해 본 발명의 범위가 제한되는 것은 아니다.This embodiment is presented only the most preferred model for the detailed description of the present invention by which the scope of the present invention is not limited.

다음과 같은 조건으로 마그네슘 다이보라이드 초전도 분말을 제조하였다.Magnesium diboride superconducting powder was prepared under the following conditions.

즉, 마그네슘 질산염과 붕산을 양이온비가 1:2가 되도록 칭량한 후 증류수에 녹인 후 여기에 에칠알콜 5%를 첨가하여 마그네슘과 붕소 금속이온이 혼합된 투명한 전구체 용액을 제조하였다.That is, magnesium nitrate and boric acid were weighed to have a cation ratio of 1: 2, dissolved in distilled water, and 5% ethanol was added thereto to prepare a transparent precursor solution in which magnesium and boron metal ions were mixed.

이때, 증류수양을 조절하여 용액의 농도를 조절하며 마그네슘 질산염과 붕산이 용해가 잘 될 수 있도록 가열하면서 교반시키는 것이 바람직하다.At this time, it is preferable to adjust the concentration of the solution by adjusting the amount of distillation and stirring while heating so that the magnesium nitrate and boric acid can be dissolved.

이렇게 하여, 얻어진 전구체 용액을 도 1과 같은 초음파 분무장치를 이용하여 분무시킨 후 750℃로 유지되는 반응기내에서 열처리하여 마그네슘 다이보라이드 초전도 분말을 제조하였다.In this way, the obtained precursor solution was sprayed using an ultrasonic atomizer as shown in FIG. 1, and then heat-treated in a reactor maintained at 750 ° C. to prepare magnesium diboride superconducting powder.

이후, 상기에서 얻어진 마그네슘 다이보라이드 초전도 분말을 주사전자현미경으로 관찰한 결과, 도 2에서와 같이 형상이 구형이고 크기가 100nm 정도 임을 확인 할 수 있었다.Then, the magnesium diboride superconducting powder obtained above was observed with a scanning electron microscope, and as shown in FIG. 2, the shape was spherical and the size was about 100 nm.

또한, 이 초전도 분말을 X선 회절분석한 결과, 도 3에서와 같이 결정상이 마그네슘 다이보라이드 단일상으로 얻어짐도 확인할 수 있었다.As a result of X-ray diffraction analysis of the superconducting powder, it was also confirmed that the crystal phase was obtained as a magnesium diboride single phase as shown in FIG. 3.

아울러, 상기에서 제조된 마그네슘 다이보라이드 초전도 분말에 초전도 전이온도를 측정하여 본 결과 37K의 전이온도를 가지고 있는 것으로 확인되었다.In addition, by measuring the superconducting transition temperature on the magnesium diboride superconducting powder prepared above, it was confirmed that it has a transition temperature of 37K.

그리고, 얻어진 마그네슘 다이보라이드 초전도 분말을 이용하여 분말충진법에 의해 선재 형태로 제작하고, 이에 대한 자장하에서의 임계전류밀도특성을 관찰 하였다.Then, using the obtained magnesium diboride superconducting powder was prepared in the form of wire by the powder filling method, and the critical current density characteristics under magnetic field were observed.

예컨대, 도 4에서와 같이 본 발명에 의해 얻어진 마그네슘 다이보라이드 초전도 분말을 사용하는 것이 기존에 시판되고 있는 마그네슘 다이보라이드 초전도 분말을 사용한 선재에 비해 고자장으로 갈수록 그 특성이 더 우수함을 확인하였다.For example, it was confirmed that the use of the magnesium diboride superconducting powder obtained by the present invention as shown in FIG. 4 is superior to the high magnetic field compared to the wire rod using the commercially available magnesium diboride superconducting powder. .

이상에서 상세히 설명한 바와 같이, 본 발명은 전구체 용액을 제조하고 이를 분무하여 열반응 및 환원 열처리에 의해 구형의 수십나노 크기에서부터 수마이크론 크기의 미세한 마그네슘 다이보라이드 분말을 제조할 수 있고, 또한 기존보다 입자크기가 작고 높은 순도를 유지할 수 있을 뿐 아니라 구형의 형상을 가지기 때문에 다심 초전도 선재 제조시 필라멘트 수를 늘릴 수 있으며, 필라멘트 크기를 줄일 수 있기 때문에 마그네슘 다이보라이드 초전도 선재의 기계가공 특성을 높일 수 있으며, 입자크기 미세화로 자속고정 역할을 할 수 있는 입계숫자를 늘려줄 수 있기 때문에 자장하에서의 임계전류밀도특성을 향상 시킬 수 있다.As described in detail above, the present invention can prepare a precursor solution and spray it to produce a fine magnesium diboride powder of spherical tens of nanometers to several microns in size by thermal reaction and reduction heat treatment, and also than conventional The small particle size, high purity, and spherical shape can increase the number of filaments when manufacturing multi-core superconducting wires, and reduce the filament size, thereby improving the machining characteristics of magnesium diboride superconducting wires. In addition, since the grain size can be increased to increase the number of grain boundaries that can act as a magnetic flux fixing, it is possible to improve the critical current density characteristics under the magnetic field.

뿐만 아니라, 이를 통하여 최종적으로 차세대 전력응용기기에서 도체로 사용되어져 자장하에서 높은 임계 전류밀도 특성에 따른 소형, 경량화 및 에너지 절감으로 신규 수요창출을 이룰 수 있다.In addition, through this, it is finally used as a conductor in the next-generation power applications can achieve new demand by small size, light weight and energy saving according to the high critical current density characteristics under the magnetic field.

Claims (5)

삭제delete 마그네슘 금속이온을 포함하는 수용액 1.0~1.5몰에 붕산 수용액 2몰을 혼합하고 이를 가열 및 교반시켜 마그네슘과 붕산 금속이온이 혼합된 수용액을 제조하는 단계와; 상기 수용액에 에칠알콜을 첨가하여 0.05~2.0mol/L 농도의 전구체 용액을 제조하는 단계와; 상기 전구체 용액을 분무장치를 이용하여 분무시킨 후 열반응장치의 반응기 내에서 열처리하여 초전도 분말을 제조하는 단계로 이루어진 마그네슘 다이보라이드 초전도 분말 제조방법에 있어서;Preparing an aqueous solution in which magnesium and boric acid metal ions are mixed by mixing 2 mol of boric acid aqueous solution in 1.0-1.5 mol of aqueous solution containing magnesium metal ions, followed by heating and stirring; Adding ethanol to the aqueous solution to prepare a precursor solution having a concentration of 0.05 to 2.0 mol / L; In the magnesium diboride superconducting powder production method comprising the step of spraying the precursor solution using a spray apparatus and then heat-treating in a reactor of a thermal reactor to produce a superconducting powder; 상기 마그네슘 금속이온을 포함하는 수용액은 질산마그네슘, 초산마그네슘, 구연산마그네슘 중에서 선택된 하나임을 특징으로 하는 마그네슘 다이보라이드 초전도 분말 제조방법.Magnesium diboride superconducting powder manufacturing method, characterized in that the aqueous solution containing magnesium metal ions is one selected from magnesium nitrate, magnesium acetate, magnesium citrate. 청구항 2에 있어서;The method according to claim 2; 상기 수용액 제조단계에서 가열 및 교반은 25~100℃에서 0.5~10시간 동안 수행하는 것을 특징으로 하는 마그네슘 다이보라이드 초전도 분말 제조방법.Magnesium diboride superconducting powder manufacturing method, characterized in that the heating and stirring in the aqueous solution manufacturing step is carried out for 0.5 to 10 hours at 25 ~ 100 ℃. 삭제delete 청구항 2에 있어서;The method according to claim 2; 상기 수용액 제조단계에서 수용액에 자속 고정 역할을 하는 나노크기의 SiC 미분체를 더 첨가하여 함께 교반되는 것을 특징으로 하는 마그네슘 다이보라이드 초전도 분말 제조방법.Magnesium diboride superconducting powder manufacturing method, characterized in that the addition of the nano-sized fine SiC powder to the magnetic flux in the aqueous solution manufacturing step and stirred together.
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