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분체공학,유동층,고분자,재료(무기,유기) : 에틸렌디아민을 이용하여 Solvothermal Synthesis로 Y2O3:Eu3+ 나노 입자의 제조
신수철 ( Sin Su Cheol ),조태환 ( Jo Tae Hwan ) 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.5
Eu doped Y₂O₃ nanoparticles were prepared with the solvothemal synthesis using ethylenediamine solvent at 200℃ for 1-5 h and then annealed in air at from 1,000℃ to 1,400 for 2 4 h. The X-ray diffraction pattern of the crystals annealed at 1,000℃ for 2 h could be indexed as pure cubic cell of Y₂O₃ with the lattice parameter a=10.6029 Å which is very close to the reported value (JCPDS Card File 41-1105, a=10.6041 Å). Average sizes of prepared phosphor particles had about 100 nm, size and spherical morphology. The phosphor panicle size decreased and the emission intensity increased as the annealing temperature increased. Through PL spectrum analysis, the 3% Eu doped Y_(2-x)O₃:Eu_(x)^(3+)(x=0.06) phosphor showed the excitation spectrum at 250 nm wavelength and the maximum emission spectrum appeared at 611nm wavelength.
신수철,장건익,Sin, Su-Cheol,Jang, Geon-Ik 한국재료학회 1998 한국재료학회지 Vol.8 No.12
MCFC(Molten Carbonate Fuel Cell) 작동온도인 $650^{\circ}C$에서 Ni 음극의 Creep 및 소결에 대한 저항성을 개선시키고자 Ni-W(WC) 복합재료를 기계적 합금법으로 제조하였다. 기계적 합금화한 분말의 XRD분석결과 밀링시간이 증가함에 따라 재료의 규칙적인 결정이 파괴되어 비정질화 되어가는 경향을 보였다. 소결은 $1280^{\circ}C$의 수소분위기에서 10시간 행하였다 소결된 시편의 dot-mapping 및 TEM 분석결과 Ni-W 계면에서의 2차상 관찰되지 않았으나 $0.1\mu\textrm{m}$ 이하의 W이 Ni 기지내에 미세하고 균일하게 분포되어 있는 것으로 나타났다. 이와같이 미세하고 균일하게 분포되어 있는 W은 고용강화 및 분산강화 효과를 통하여 Ni음극의 기계적 특성을 향상시킬 것으로 기대된다. By the mechanical alloying method Ni-W(WC) composite materials were prepared to improve the resistance for creep and sintering of Ni-anode at the operating temperature of$ 650^{\circ}C$. Amorphization was observed from the XRD analysis of mechanically alloyed powder caused by the destruction of ordered crystals. Sintering was performed at $1280^{\circ}C$ for 10 hours in $H_2$ atmosphere. From the result of dot-mapping and TEM analysis the second phase was not observed at Ni-W interface while W particles of less 0.lam were distributed finely and uniformly in Ni matrix. This finely and uniformly distributed W in Ni matrix is expected to enhance the mechanical properties of Ni-anode through the dispersion and solid solution hardening mechanisms.