• 한국산학기술학회논문지
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• 제2권2호
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• pp.91-94
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• 2001

Glass ceramics composed of (5-X)$Li_2O$ㆍ$XAg_2O$ㆍ36CaOㆍ$20TiO_2$.27$P_2O_5$(X=1 to 5) were prepared by melting process and 2 step heat treatment for nucleation at$610^{\circ}C$ and crystallization at $730^{\circ}C$, Fabricated crystal phases were $LiTi_2(PO_4)_3$(LTP),$AgTi_2(PO_4)_3$(AgTP)와 $\beta-Ca_3(PO_4)$. Antibacterial effects and characterizations of the glass ceramics as $Ag_2$O content were investigated. Staphylococcus aureus and Salmonella typhi were used in this study. Staphylococcus aureus and Salmonella typhi bacteria were removed 5 hours added after glass ceramics.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 The 8th Asian Symposium on Precision Forging ASPF
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• pp.189-192
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• 2003

The Electro-thermal Explosion Coating (EEC) technique is a new surface treatment technology emerged in recent years. It uses an electrical discharge (with very high voltage from 5 to 30 kV or more) to produce a pulse current with large density inside the material to be deposited, the metal wire undergo the heating, melting, vaporization, ionization and explosion processes in a very short time (from tens ns to several hundreds ${\mu}s$), and the melted droplets shoot at the substrate with a very high velocity (3000 - 4500 m/s), so that the coating materials can be deposited on the surface of the substrate. Coatings with nano-size grains or ultra- fine grains can be formed because of rapid solidification (cooling rate up to $10^6-10^9\;k/s$). Surface of the substrate (about $1-5{\mu}m$ in depth) can be melted rapidly and coatings with very high bonding strength can be obtained.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.478-481
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• 2002

We carried out the experiments for fabricating $Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{x}$(Bi2223) superconductor thick films on Cu tapes. Cu-free (Bi,Pb)-Sr-Ca-0 powder mixtures were screen- printed on Cu tapes and heat-treated at 840-$860^{\circ}C$ for several minutes in air. Surface microstructures and phases of films were analyzed by XRD and optical microscope. The electric properties of superconducting films were examined by the four probe method. At heat-treatment temperature, the printing layers were in a partially molten state by liquid reaction between CuO in the oxidized copper tape and the precursors which were printed on Cu tapes. During the heat-treatment procedure, it is thought that Bi2223 superconducting particles nucleate at interfaces between Bi2212 phase and liquid.

• 열처리공학회지
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• 제26권1호
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• pp.1-6
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• 2013

The B2-ordered NiAl has attracted much attention as one of the candidates as a next generation high temperature material, because it has a high melting temperature, a low specific gravity and an excellent high temperature oxidation resistance. However, the application of NiAl to structural materials needs the improvement of its brittleness at room temperature. The study was carried out on the relation between several properties of NiAl and some variation of Ni content within NiAl phase, which means deviations from the stoichiometric composition. The main results were as follows; (i) Good ductility was obtained at the testing temperature more than 1073 K irrespective of Ni content. (ii) Increasing Ni content offered preferable tensile properties. (iii) Every NiAl with varying Ni contents showed the superior oxidation resistance.

• 한국세라믹학회지
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• 제48권2호
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• pp.189-194
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• 2011

Metallurgical grade silicon was recovered from slurry waste for ingot sawing process by acid leaching and thermal treatment. SiC abrasive was removed by gravity concentration and centrifugation. Metal impurities were removed by the acid leaching using HF/HCl. The remaining SiC was separated by the thermal treatment at $1600^{\circ}C$ in an inert atmosphere by the difference in melting points. The purity of the obtained silicon was found to be around 99.7%.

• 한국주조공학회지
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• 제15권5호
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• pp.477-482
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• 1995

A computer simulation model of various smelting process for melting waste sand was developed by using energy and material balance concept. This model can predict the coal, flux and oxygen consumption and the volume and temperature of off-gas. The major critical variables for smelting process can be explained by using the analysis of energy and material balance. The major conclusions were as follows; 1. The most important variables for smelting process were high post-combustion ratio, high heat transfer efficiency and refractory protection technology. 2. For saving energy in this smelting process, selection of raw materials i.e coal, flux are very important, espacially using of low volatile coal is very profitable. 3. The treatment cost of waste sand is high and environmental restriction is severe, in this reason we must be concerned in the treatment of waste sand by smelting process.

• Applied Science and Convergence Technology
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• 제25권6호
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• pp.149-153
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• 2016

Thermal oxidation has significant potential for use in synthesizing metal-oxide nanostructures from metallic materials. However, this method has limited applicability to the synthesis of multi-morphology NiO from Ni foil. Techniques consisting of mechanical and chemical approaches were used to pre-treat the Ni foil (prior to oxidation) to promote the formation of nanowires and nanoplates on the NiO layer. These morphologies were realized on the Ni foils scratched by sand paper and a knife, respectively, and subsequently heat-treated at $500^{\circ}C$ for 24 h. Small nanowires (diameter: <10 nm) formed on the Ni foil treated by absolute $HNO_3$ and then oxidized at $500^{\circ}C$ for 24 h. The formation of various morphologies (on the pre-treated Ni foil), which differ from that formed in the case of pristine Ni foil after oxidation, may be attributed to the surface melting phenomenon that occurs during the nucleation process.

• 열처리공학회지
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• 제10권1호
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• pp.71-78
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• 1997

This work was to investigate suitable tool steels for hardening using laser beam, and was studied on carbon tool steels and alloyed tool steels such as STC3 steel, STS3 steel, STD11 steel and SKH51 steel. The surface hardness of HV700-1000 and the hardening depth of 2-2.5mm were obtained on STC3 steel and STS3 steel, and HV800-1000 was obtained on SKH51 steel, but STD11 steel was not enough. Except STD11 steel, all steels used in this study can be hardened by laser quenching or laser rapid melting.

• 한국결정성장학회지
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• 제24권4호
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• pp.140-144
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• 2014

Co(0.7 wt%)와 Pr(2.0, 3.5 및 5.0 wt%)이 첨가된 큐빅지르코니아($ZrO_2:Y_2O_3=50:50wt%$) 단결정을 스컬용융법으로 성장 후 $N_2$ 분위기에서 $1150^{\circ}C$로 5시간 동안 열처리 하였다. 갈색의 단결정들은 각각 어두운 갈녹색, 녹청색 또는 밝은 녹색으로 변화되었다. 열처리 전 후의 YSZ 단결정들을 직경 7.5, 두께 3 mm의 웨이퍼로 연마 하여 UV-VIS 분광광도계 및 XRD(X-ray diffraction)로 광학적 또는 구조적 특성 분석을 행하였다. $Co^{2+}$(약 589 nm: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8+{\Gamma}_7[^4T_1(^4F)]$, 약 610 nm: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8[^4T_1(^4F)]$, 약 661 nm: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_6[^4T_1(^4F)]$ 및 $Pr^{3+}$(약 450 nm: ${^3}H{_4}-{^3}P{_2}$, 약 473 nm: ${^3}H{_4}{\rightarrow}{^3}P{_1}$, 약 484 nm: ${^3}H{_4}{\rightarrow}{^3}P{_0}$)에 의한 흡수, 이온화에너지 및 격자상수 변화를 확인하였다.

• Progress in Superconductivity
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• 제9권1호
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• pp.111-114
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• 2007

We have investigated the effect of different heat treatment processes on electrical and magnetic properties of Bi2212/Ag ROSAT wire. The ROSAT wire was fabricated by stacking and arranging 12 filaments Bi2212/Ag tapes in triple rotation symmetry in a Ag tube. ROSAT wires have been prepared using a partial melting method with changing $T_{max}$ and $T_a$ in oxygen atmosphere. The highest critical current density($J_c$) at 65 K under 0 T was $21,158\;A/cm^2$ for wire prepared $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$, respectively. SEM results indicated that the wire prepared at $890\;^{\circ}C(T_{max})$ and $840\;^{\circ}C(T_a)$ showed better directional phases than the other samples. However the result of magnetic susceptibility measurement indicates that the wire prepared $890\;^{\circ}C(T_{max})$ and $835\;^{\circ}C(T_a)$ had better superconducting phases than the other samples. It was revealed that heat treatment temperature was important factor for superconducting properties of the ROSAT wire.