http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A1-Ti-(Si)계 합금의 기계적 합금화 및 성형체의 미세조직
최철진 한국분말야금학회 1995 한국분말재료학회지 (KPMI) Vol.2 No.2
Alloying behavior of nanocrystalline Al-Ti-(Si) composite powders via mechanical alloying (MA) has been investigated, and the effect of Si on the microstructural changes during MA was discussed. The microstructures of both MA powders and extruded compacts were examined. In Al-Ti system, the solid solutionized nanocrystalline powders could be obtained by MA. On the contrary, fine Si particles were embedded as an elemental state in the matrix of Al-Ti-Si system because of the brittleness and the negligible solid solubility of Si in Al. After hot extrusion, $Al3Ti$ phase was finely precipitated in Al-10fSTi alloy, and Si particles were dissolved to form $(Al, Si)_3Ti$ phase in Al-10%Ti-2%Si alloy.
화학기상응축공정(Chemical Vapor Condensation)으로 제조된 Co 나노분말의 미세구조 및 자기적 성질에 미치는 운송기체의 영향
최철진,유지훈,김진천,김병기 한국분말야금학회 2004 한국분말재료학회지 (KPMI) Vol.11 No.1
The nano-sized Co particles were successfully synthesized by chemical vapor condensation (CVC) process using the precursor of cobalt carbonyl ($Co_2(CO)_8$). The influence of carrier gases on the microstructure and magnetic properties of nanoparticles was investigated by means of XRD, TEM, XPS and VSM. The Co nano-particles with different phases and shapes were synthesized with a change of carrier gas : long string morphologies with coexistence of fcc and hcp structure in Ar carrier gas condition; finer Co core in a mass of cobalt oxide with only fcc structure in He; rod type cobalt oxide phase in Ar+6vol%$O_2$. The saturation magnetization and coercivity was lower in Co nanoparticles synthesized in He carrier gas, due to their finer size.
화학기상응축공정(Chemical Vapor Condensation)으로 제조된 나노 Fe 입자의 내부구조 및 자기적 성질
崔哲鎭,金柄淇 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.6
The Nano-sized Fe particles were successfully synthesized by Chemical Vapor Condensation (CVC) process using the precursor of iron pentacarbonyl (Fe(CO)_5) as a source. The influence of CVC parameters on the formation of nanoparticle, the microstructure and magnetic properties was studied. The synthesized nanoparticles consisted of the core-shell type structure with nearly spherical shape and 5-13 ㎚ in mean size. Average particle size increased with increasing the decomposition temperature. The size distribution became wider and asymetric with increase of particle size. The lattice parameter of metallic core increased with decreasing the particle size. This could be explained by the coherency relationship between the Fe core and Fe_3O_4 oxide shell. With change of particle size and core microstructure, the magnetic state of Fe nanoparticle was changed from ferromagnetism to superaparamagnetism.
급냉응고 및 기계적 합금화된 Al-Ti계 합금의 기계적 성질
최철진 한국분말야금학회 1995 한국분말재료학회지 (KPMI) Vol.2 No.1
Rapidly solidified and mechanically alloyed Al-Ti base alloys were prepared by gas atomization and attritor milling separately. The gas atomized and the mechanically alloyed powders were consolidated after preheating at $450^{\circ}C$, and then heat treated isochronally for 1 hour to observe the microstructures and to investigate the mechanical properties. Stable phases of precipitates in the Al-Ti-Si and the Al-Ti-Zr alloys were identified as DO22-$(Al,Si)_3Ti$ and $Do_{23}-Al_3(Ti, Zr)$ each. Among the alloys, the mechanically alloyed Al-l0Ti-2Si alloy showed superior thermal stability and mechanical properties at elevated temperature. The additions of third elements, such as Si and Zr, to Al-Ti alloys seemed to improve the mechnical properties remarkably by stabilizing the microstructure and the precipitate phases in the consolidated alloys.
최철진,박지훈,임정태,김종우 대한금속·재료학회 2021 대한금속·재료학회지 Vol.59 No.11
Permanent magnetic materials are essential for converting mechanical and electric energy, and are needed in electric vehicles, electronics, wind turbines, and etc. However, high performance rare-earth element based magnets have many limitations, including critical materials problems and the degradation of magnetic properties at elevated temperatures. There has been increasing international demand to solve these problems, and to develop new magnets with reduced rare earth materials, or free magnets based on metallic alloys. This paper describes current research trends, and state of art and future research directions for next generation permanent magnetic materials, to accelerate their research and rapid industrialization.