In existing ceramic mold manufacturing processes, inorganic binder systems (Si-Na, two-component system) are applied to ensure the effective firing strength of the ceramic mold and core. These inorganic binder systems makes it possible to manufacture a ceramic mold and core with high dimensional stability and effective strength. However, as in general sand casting processes, when molten metal is injected at room temperature, there is a limit to the production of thin or complex castings due to reduced fluidity caused by the rapid cooling of the molten metal. In addition, because sodium silicate generated through the vitrification reaction of the inorganic binder is converted into a liquid phase at a temperature of 1,000 °C. or higher, it is somewhat difficult to manufacture parts through high-temperature casting. Therefore, in this study, a high-strength ceramic mold and core test piece with effective strength at high temperature was produced by applying a Si-Na-Ti three-component inorganic binder. The starting particles were coated with binary and ternary inorganic binders and mixed with an organic binder to prepare a molded body, and then heat-treated at 1,000/1,350/1,500 °C to prepare a fired body. In the sample where the two-component inorganic binder was applied, the glass was liquefied at a temperature of 1,000 °C or higher, and the strength decreased. However, the firing strength of the ceramic mold sample containing the three-component inorganic binder was improved, and it was confirmed that it was possible to manufacture a ceramic mold and core via high temperature casting.

A molten salt reactor (MSR) that uses molten salt mixtures as nuclear liquid fuel has recently received much attention due to its inherent safety. Various fluoride and chloride salt mixtures are considered as fluid fuel for MSRs. Among those, NaCl-MgCl2-UCl3 system is the one of the most promising candidates for molten salt fast reactor. The comprehensive information on thermo-physical properties such as density, viscosity, heat capacity and thermal conductivity are fundamental to MSR design development, but experimental data for NaCl-MgCl2-UCl3 system are unknown to the best of our knowledge. In this study, we estimated the thermophysical properties of NaCl-MgCl2-UCl3 system. The properties were calculated by mole fraction additive method using reliable experimental data from pure salt system. Other methods, such as rule of additivity of molar volume for density, modified Dulong-Petit method for heat capacity, and Rao-Turnbull prediction and Ignatieve-Khokolve correlation for thermal conductivity, have also been applied. Estimated values for the properties were compared with each other as well as available binary experimental data.

Lead free (1-x)(0.675BiFeO3-0.325BaTiO3)- xLiTaO3 (BFBTLT, x = 0, 0.01, 0.02, and 0.03, with 0.6 mol% MnO2 and 0.4 mol% CuO) were prepared by a solid state reaction method, followed by air quenching and their crystalline phase, morphology, dielectric, ferroelectric and piezoelectric properties were explored. An X-ray diffraction study indicates that lithium (Li) and tantalum (Ta) were fully incorporated in the BFBT materials with the absence of any secondary phases. Dense ceramic samples (> 92 %) with a wide range of grain sizes from 3.70 μm to 1.82 μm were obtained in the selected compositions (0 ≤ x ≤ 0.03) of BFBTLT system. The maximum temperatures (Tmax) were mostly higher than 420 oC in the studied composition range. The maximum values of maximum polarization (Pmax ≈ 31.01 μC/cm2), remnant polarization (Prem ≈ 22.82 μC/cm2) and static piezoelectric constant (d33 ≈ 145 pC/N) were obtained at BFBT-0.01LT composition with 0.6 mol% MnO2 and 0.4 mol% CuO. This study demonstrates that the high Tmax and d33 for BFBTLT ceramics are favorable for industrial applications.

용해성이 우수하며, 강한 electron-withdrawing 특성을 나타내는 cyano group 을 가지는, 새로운 전자acceptor 재료인 malononitrile 유도체 (2-(2,6-bis((E)-4-tert-butylstyryl)-4H-pyran-4-ylid-ene)malononitrile (t-BuPM)을 합성하였다. 합성된 acceptor 재료 t-BuPM을 donor와 acceptor 재료로 널리 사용되고 있는 poly[2-Methoxy-5-(2-EthylHexyloxy)-P-Phenylene-Vinylene](MEH-PPV)와 (6)-1-(3-(methoxycarbonyl)propyl)-{5}-1-1-phenyl-[5,6]-fullerene (PCBM)과 함께ternary blend system으로 유기 태양전지 소자를 제작하였다. 소자는 ITO/PEDOT:PSS/MEH-PPV:t-BuPM:PCBM/Al 구조와 같이 제작하여 광전변환 특성을 측정하였다. 합성된 재료의 HOMO와LUMO energy level은 -5.97,-3.49eV로 측정되었으며, t-BuPM을 사용하여 ternary blend system 으로 제작된소자의 에너지변환 효율은 AM 1.5G, 1 sun 조건(100mA/cm2)에서 1.85%로 측정되었다. Short circuit current density (Jsc)는 5.54mA/cm2, fillfactor(FF)는 41%, open circuit voltage(Voc)는 0.80 V로 측정되었다.

Metallic compound of ternary Al-B-C system was prepared by mechanical alloying (MA) using Al, boron and graphite powders as starting materials. MA was carried out using Spex 8000 mixer/mill for 50 hours in an argon atmosphere without process control reagent such as methyl alcohol. The MA powders obtained were heat-treated in vacuum at the temperature of 873 and 1273 K for 5 hour. Pure ternary Al-B-C compound was obtained in the chemical content of Al:B:C=55:27:18. The ternary compound obtained in this study has a new phase whose crystal structure is not identified yet.

W-12.8wt%Cu-7.2%Pb powders were milled at room temperature and to investigate the mechanical alloying behavior of immiscible W-Cu-Pb system and the effect of milling temperature on the extent of alloying and microstructural refinement. W-Cu-Pb powder reached steady state after further extended milling due to Pb addition, compared to the W-Cu system. The cryomilling at caused the more refinement of powder particle size, and enhanced the solubility of Cu or Pb in W, compared with milling at room temperature. In W-12.8wt%Cu-7.2%Pb powder cryomilled at , the monotectic temperature of Cu-Pb as well as the melting temperature of Cu was decreased by refinement of Cu crystalline size, and the most amorphization was occurred after milling for 150 h.