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양상선(Sangsun Yang),이고르 알트만(Igor S. Altman),피터 피키차(Peter V. Pikhitsa),최만수(Mansoo Choi) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Size and crystalline phase changes of Fe₂O₃ nanoparticles formed in a H₂/O₂ flame have been investigated. At flame temperatures below 1350°C, the mean particle size increased monotonously with the distance from the burner edge; but in high-temperature flames above 1650°C, it suddenly decreased from 20 nm to ~3 nm with the distance from the burner edge. The results of X-ray diffraction and HRTEM showed that this sudden reduction of the size of nanoparticles was accompanied by a partial phase transformation from γ-Fe₂O₃ into α-Fe₂O₃. We suggest the structural instability due to γ-to α-phase transformation as a mechanism for a rapid fragmentation of 20 nm particles into 3 nm ones.
양상선(Sangsun Yang),장윤형(Yoon-Hyung Jang),김창혁(Chang Hyuk Kim),황창선(Changseon Hwang),채석병(Sukbyung Chae),정세권(Sekwon Jung),이정훈(Jeonghoon Lee),최만수(Mansoo Choi) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
Flame metal combustion method for continuously synthesizing metal oxide nanoparticles with a high production rate was proposed. Micro-sized metal powder precursors injected into a hydrogen-oxygen flame were converted into metal oxide nanoparticles with good crystallinity. There is no limitation in the selection of precursors including metal chloride and metal organic powders to synthesize nanoparticles. Various oxides such as magnesia, iron oxides and zinc oxide were generated by using this method. The sizes of oxide nanoparticles were found to be dependent on flame temperatures and residence times.
구리를 함유하지 않은 친환경 자동차 브레이크 패드의 마모 특성에 관한 연구
김기봉,양상선,이성주,황석훈,김신욱,김용진,Kim, Ki-Bong,Yang, Sangsun,Lee, Seong-Ju,Hwang, Suk-Hun,Kim, Sin-Wook,Kim, Yong-Jin 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.1
The friction characteristics of Al-Fe alloy powders are investigated in order to develop an eco-friendly friction material to replace Cu fiber, a constituent of brake-pad friction materials. Irregularly shaped Al-Fe alloy powders, prepared by gas atomization, are more uniformly dispersed than conventional Cu fiber on the brake pad matrix. The wear rate of the friction material using Al-8Fe alloy powder is lower than that of the Cu fiber material. The change in friction coefficient according to the friction lap times is 7.2% for the Cu fiber, but within 3.8% for the Al-Fe alloy material, which also shows excellent judder characteristics. The Al-Fe alloy powders are uniformly distributed in the brake pad matrix and oxide films of Al and Fe are homogeneously formed at the friction interface between the disc and pad, thus exhibiting excellent friction and lubrication characteristics. The brake pad containing Al-Fe powders avoids contamination by Cu dust, which is generated during braking, by replacing the Cu fiber while maintaining the friction and lubrication performance.
슬러리 코팅 공정으로 제조된 Fe 폼의 기공 특성에 미치는 바인더 함량의 영향
최진호,양상선,김양도,윤중열,Choi, Jin Ho,Yang, Sangsun,Kim, Yang-Do,Yun, Jung-Yeul 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.6
Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process. In this study, the binder contents were controlled to produce the Fe foam with different pore size, strut thickness and porosity. Firstly, the slurry was prepared by uniform mixing with Fe powders, distilled water and polyvinyl alcohol(PVA) as initial materials. After slurry coating on the polyurethane(PU) foam the sample was dried at $80^{\circ}C$. The PVA and PU foams were then removed by heating at $700^{\circ}C$ for 3 hours. The debinded samples were subsequently sintered at $1250^{\circ}C$ with holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase.
플라즈마 공정으로 구상화된 티타늄 분말과 금속사출성형 공정을 이용한 치과용 부품 제조
곽지나,양상선,윤중열,김주용,박성진,김현승,김용진,박용호,Gwak, Ji-Na,Yang, Sangsun,Yun, Jung-Yeul,Kim, Ju-Yong,Park, Seongjin,Kim, Hyun-Seung,Kim, Yong-Jin,Park, Yong-Ho 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.6
This research presents a preparation method of dental components by metal injection molding process (MIM process) using titanium scrap. About $20{\mu}m$ sized spherical titanium powders for MIM process were successfully prepared by a novel dehydrogenation and spheroidization method using in-situ radio frequency thermal plasma treatment. The effects of MIM process parameters on the mechanical and biological properties of dental components were investigated and the optimum condition was obtained. After sintering at $1250^{\circ}C$ for 1 hour in vacuum, the hardness and the tensile strength of MIMed titanium components were 289 Hv and 584 MPa, respectively. Prepared titanium dental components were not cytotoxic and they showed a good cell proliferation property.
Kinetic Spray 공정으로 제조된 Nb 코팅 소재의 미세조직 및 물성에 미치는 열간 등압 성형(HIP)의 영향
이지혜,양상선,이기안,Lee, Ji-Hye,Yang, Sangsun,Lee, Kee-Ahn 한국분말야금학회 2016 한국분말재료학회지 (KPMI) Vol.23 No.1
Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it's extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of $23.8{\mu}m$. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.
Fe-Cr-Mo 합금 분말의 성형 및 소결특성에 미치는 입도분포 영향
김기봉,양상선,김용진,박용호,Kim, Ki-Bong,Yang, Sangsun,Kim, Yong-Jin,Park, Yong-Ho 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.1
The effect of particle size distribution on green and sintered properties of Fe-Cr-Mo prealloy powder was investigated in this study. For the study, prealloyed Fe-Cr-Mo powders with different particle sizes were mixed as various ratios and cold compacted at various pressure and sintered at $1250^{\circ}C$ for 30 min, $90%N_2+10%H_2$ atmosphere in the continuous sintering furnace. The results shows that the powders with large particle size distribution have high compressibility and low ejection force. However the green strength are much less than those with small particle size distribution. Tensile prperties of the sintered specimes with large particles size also have high strength and elongation.
Al-Si-SiC 복합분말과 Al-Zn-Mg계 합금분말이 혼합된 분말의 소결 거동 및 기계적 특성연구
장광주,김경태,양상선,김용진,박용호,Jang, Gwang-Joo,Kim, Kyung Tae,Yang, Sangsun,Kim, Yong-Jin,Park, Yong-Ho 한국분말야금학회 2014 한국분말재료학회지 (KPMI) Vol.21 No.6
Al-Si-SiC composite powders with intra-granular SiC particles were prepared by a gas atomization process. The composite powders were mixed with Al-Zn-Mg alloy powders as a function of weight percent. Those mixture powders were compacted with the pressure of 700 MPa and then sintered at the temperature of $565-585^{\circ}C$. T6 heat treatment was conducted to increase their mechanical properties by solid-solution precipitates. Each relative density according to the optimized sintering temperature of those powders were determined as 96% at $580^{\circ}C$ for Al-Zn-Mg powders (composition A), 97.9% at $575^{\circ}C$ for Al-Zn-Mg powders with 5 wt.% of Al-Si-SiC powders (composition B), and 98.2% at $570^{\circ}C$ for Al-Zn-Mg powders with 10 wt.% of Al-Si-SiC powders (composition C), respectively. Each hardness, tensile strength, and wear resistance test of those sintered samples was conducted. As the content of Al-Si-SiC powders increased, both hardness and tensile strength were decreased. However, wear resistance was increased by the increase of Al-Si-SiC powders. From these results, it was confirmed that Al-Si-SiC/Al-Zn-Mg composite could be highly densified by the sintering process, and thus the composite could have high wear resistance and tensile strength when the content of Al-Si-SiC composite powders were optimized.
Fabrication of Fe Foam using Slurry Coating Process
윤중열,박다희,양상선,왕제필,Yun, Jung-Yeul,Park, Dahee,Yang, Sangsun,Wang, Jei-Pil The Korean Institute of Resources Recycling 2017 資源 리싸이클링 Vol.26 No.6
메탈폼은 매우 많은 기공을 포함하는 세포상 구조를 갖는 고체금속을 일컫는다. 특히 관통 기공 같은 개기공들은 고온용 필터 및 촉매 지지체 등으로 산업적으로 많이 사용되고 있다. 본 연구에서는 슬러리 코팅공정으로 90% 이상의 기공율과 2 mm 이상의 기공크기를 갖는 Fe 폼을 제조하였다. 이때 Fe 분말과 $Fe_2O_3$ 분말의 혼합비를 달리하여 기공율과 기공크기를 제어하였다. 이를 위해 우선 분말, 증류수 및 폴리비닐알콜(PVA)를 균일하게 혼합하여 슬러리를 제조하였다. $Fe_2O_3$ 분말의 혼합 비율이 증가할수록 PU 폼에 코팅된 슬러리의 양이 증가한 반면 Fe 폼의 수축 및 기공율은 각각 감소하였다. Metal foams have a cellular structure consisting of a solid metal containing a large volume fraction of pores. In particular, open pores which are penetrable pores are necessary for industrial applications such as in high temperature filters and as support for catalysts. In this study, Fe foam with greater than 90% porosity and 2-mm pore size was successfully fabricated using a slurry coating process and the pore properties were characterized. The Fe and $Fe_2O_3$ powder mixing ratios were controlled to produce Fe foam samples with different pore sizes and porosity. First, the slurry was prepared through the uniform mixing of powders, distilled water, and polyvinyl alcohol(PVA). The amount of slurry coated with the PU foam increased with increasing $Fe_2O_3$ mixing powder ratio, but the shrinkage and porosity of the Fe foams decreased, respectively, with increasing $Fe_2O_3$ mixing powder ratio.
실버 나노분말을 이용한 메탈메쉬용 페이스트의 충전 및 와이핑 특성
김기동,남현민,양상선,박이순,남수용,Kim, Gi-Dong,Nam, Hyun-Min,Yang, Sangsun,Park, Lee-Soon,Nam, Su-Yong 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.6
A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of $2-5{\mu}m$) onto a PET film, filling it with silver paste, wiping of the surface, and heat-curing the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.