• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.53-54
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• 2006

Ti-Zr-Ni coatings deposited by low vacuum plasma spray technique consisted of nanometer-sized $W-Ti_{50}Zr_{35}Ni_{15}$ 1/1 cubic approximant and TiZrNi Laves phases as well as a low volume fraction of $ZrO_2$ phase. The shift of composition during deposition of the quasicrystalline powders and the presence of $ZrO_2$ phases are believed to be responsible for the reduced corrosion performances evaluated by means of electrochemical tests in a Hanks' Balance Salt Solution at $37^{\circ}C$.

• 한국자기학회지
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• 제19권6호
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• pp.216-221
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• 2009

Y-type 바리움 페라이트 $Ba_2Co_2Fe_{12}O_{22}$를 고상반응법으로 제조하고 금속이온몰비($Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$)와 열처리 온도가 자기적 성 질과 미세구조에 미치는 영향에 대하여 조사하였다. 상분석과 미세구조는 각각 XRD(X-ray diffractometer)와 FESEM(field effect scanning electron microscope)을 이용하여 조사하였으며 분말의 자기적 성질은 VSM(vibrating sample magnetometer)을 이용하여 조사하였다. 금속이온몰비($Fe^{3+}:\;Ba^{2+}:\;Co^{2+}$)가 6 : 1 : 1인 조성의 분말을 $1050\;{^{\circ}C}$에서 열처리하였을 때 단일 상이 합성되었으며 8 : 1 : 1인 조성의 분말을 $1200\;{^{\circ}C}$에서 열처리하였을 때 가장 높은 포화자화값(39.1 emu/g)을 나타내었다.

• 한국세라믹학회지
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• 제39권10호
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• pp.903-906
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• 2002

Nanosized $Mn_xFe_2O_4$ powders were prepared in ethylene glycol solution under mild temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The average size and distribution of the synthesized $Mn_xFe_2O_4$ powders was about 20 nm and broad, respectively. The phase of synthesized particles was crystalline reacted at 200${\circ}C$ for 6h. The magnetic properties of the synthesized $Mn_xFe_2O_4$ powders were about 35-60 (emu/g) with superparamagnetic character.

• Progress in Superconductivity
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• 제5권1호
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• pp.65-69
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• 2003

Many researches on fabrication process for BSCCO precursor powders have been developed for high J$_{c}$ BSCCO-2223 tape. Spray pyrolysis method for fabrication of precursor powder has many advantages, such as high purity, fine particle size and low carbon content of BSCCO precursor powder. Fine, spherical powders were prepared by ultrasonic spray pyrolysis from the aqueous solution of metal nitrates. BSCCO precursor powders were synthesized with various solutes concentration and heat treatment conditions. Average particle size for spray pyrolysis powders was $1.5∼3\mu\textrm{m}$. Bi-2223/Ag tape was prepared by PIT method and followed by various sintering conditions. BSCCO precursor powders were characterized by XRD, SEM, EDS, Carbon content and particle size analysis.s.

• 한국분말재료학회지
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• 제6권4호
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• pp.277-285
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• 1999

Mechanical properties of nanocrystalline Al-5at.%Ti alloy were investigated through high temperature compression test. Al-5at.%Ti nanocrystalline metal powders, which had finer and more equiaxed shape than those produced at room temperature, were produced by mechanical alloying at low temperature. The powders were successfully consolidated to 99fo of theoretical density by vacuum hot pressing. XRD and TEM analysis revealed that $Al_3Ti$ intermetallic compounds formed inside powders and pure Al region with coarse grains formed between powders, especially at triple junction. Mechanical properties in terms of hardness and strength were improved by grain size refinement, but ductility decreased presumably due to the formation of the weak interfaces between Al pool and powders.

• 한국결정성장학회지
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• 제11권4호
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• pp.176-179
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• 2001

Iron oxide powders were prepared under high temperature (up to $175^{\circ}C$) and pressure conditions( up to 129 pasi) by precipitation from metal nitrates with aqueous potassium hydroxide. Various types of iron oxide powders were obtained at different conditions. The size and the shape of the particles can be controlled as afunction of starting solution pH. The average particles size of the synthesized iron oxide powders increased, the particle shapes of the powders became fibrous, and the crystalline phase of the powder changes from iron oxide to iron hydroxide with increasing solution pH. The effects of synthesis parameters are discussed.

• 한국세라믹학회지
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• 제25권3호
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• pp.284-292
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• 1988

Alumina-zirconia composite powders for the purpose of improving fracture toughness and thermal shock resistance of alumina were prepared by the emulsion-kerosene drying method. The average particle size of composite powders was less then 1 $\mu\textrm{m}$ and their shapes were spherical. It was shown that the average particle size of composite powders decreased with the concentration of metal-salt in solution and the amount of span 80 added when preparing emulsions. The structure of all zirconia in composite powders heat-treated at 1200$^{\circ}C$ was a tetragonal form at room temperature. This result implied that fine zirconia particles were homogeneously dispersed in the alumina matrix.

• 한국세라믹학회지
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• 제27권8호
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• pp.1064-1070
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• 1990

ZrO2 fine powders were prepared by hydrolysis, adding 0.1, 0.2, 0.3, 0.4, 0.5, 0.6mol/1H2O/ethanol to 0.1 mol/l Zr(OC3H7)4/ethanol. When hydrolized by adding 0.1mol/l Zr(OC3H7)4/ethanol to 0.1, 0.2mol/l H2O/ethanol., spherical monodispersed ZrO2 fine powders were obtained. And in this condition average sizes were about 0.5, 0.3${\mu}{\textrm}{m}$, respectively. The more H2O/ethanol concentration increased, the more the particle size decreased and the particles were agglomerated strongly. Prepared powders were amorphous and hydrates. The calcined powders with 43$0^{\circ}C$ and 100$0^{\circ}C$ were showed tetragonal and monoclinic phase, respectively.

• 공업화학
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• 제16권4호
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• pp.542-548
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• 2005

몇 가지 금속 산화물에 플루오르르 치환된 카르복시산의 자기조립박막을 제조하였다. 사슬 길이의 영향을 비교하기 위하여 퍼플루오르도테칸 산과 퍼플루오르옥타데칸 산을 사용하였다. 사용된 금속 산화물은 알루미나, 탄탈리아, 티타니아, 지르코니아였다. 자기조립박막의 형성은 DRIFT (Diffuse Reflectance Infrared Fourier Transform) 분광법으로 확인하였다. 퍼플루오르탄화수소는 소수성을 가지므로 형성된 자기조립박막도 소수성을 지닐 것으로 예측된다. 형성된 자기조립박막의 DRIFT 스펙트럼의 품질은 금속산화물의 성분 원소뿐만 아니라 분말으 크기에 따라서도 달라졌다.

• 한국결정성장학회지
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• 제30권6호
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• pp.220-225
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• 2020

반응부, 이송부, 포집부로 이루어진 기상합성장치를 구축하여 Oxide TFT의 대표적인 물질인 IGZO 반도체용 타겟의 기초 소재인 산화갈륨 나노분말을 기상합성법으로 제조하였다. 반응부에서 갈륨 금속을 증발시켜 1150℃ 이상의 온도에서 산화갈륨 나노분말이 만들어지는 것을 확인하였다. 갈륨 금속은 증발 즉시 반응부에서 산화갈륨 나노분말로 합성되었으며, 반응부의 온도가 증가함에 따라 높은 결정도와 큰 입자 크기를 보였다. 또한, 합성된 산화갈륨 나노분말은 구형의 모양을 가지면서 매우 낮은 응집성을 가졌다. 기상합성법으로 얻은 산화갈륨 나노분말을 상용 산화인듐, 산화아연 분말(몰비 = 1 : 1 : 1)과 혼합하여 소결을 시행한 결과, 소결온도 1450℃에서 5.83 g/㎤의 최대밀도를 얻어 같은 조건하에서 상용 산화갈륨 분말을 이용해 만든 IGZO 소결체(5.61 g/㎤)보다 높은 밀도를 얻음을 볼 수 있었다.