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Titanium 소재를 이용한 연료전지 분리판 제조 특성 및 TiN 박막 물성 평가
이경훈(K. H. Lee),진철규(C. K. Jin),강충길(C. G. Kang) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.10
In this study, the rubber pad for forming process is used to fabricate the micro-channel plate of Titanium for the fuel cell. The geometry of plate should have micro-channel and thin for high-efficiency heat exchanger. The micro-channel plate was fabricated using a hydraulic press with a capability of 200 ton according to the various parameters (type of plate, plate thickness, punch speed, press pressure, rubber thickness, rubber hardness, draft angle)of the rubber pad forming in order to evaluate the formability. TiN films were deposited by reactive DC magnetron sputtering (DCMS) with an electromagnetic field system (EMFS). The microstructure and corrosion resistance of the TiN-coated Titanium substrates were estimated by Nano-indentationXP (MTS), Atomic Force Microscopy (AFM), and electrochemical methods. This improved corrosion resistance of the TiN films could be attributed to the densification of the film caused by enhancement of nitrification with increasing high reactive nitrogen radicals.
이경훈(K. Lee),곽은정(E.J. Kwak),김헌영(H. Y. Kim),이기동(Gi-Dong Lee),박종규(Jong-Kyu Park),서창희(Chang Hee Suh) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.5
In hot press forming process, the desired high strength can be obtained through quenching process after cold forming of product. The quenching process, however, accompanies undesired distortion due to the volume change during the phase transformation as well as by thermal contraction. In this study the numerical simulation with DEFORM3D-Micorstucture is used to predict the deformed shape during the quenching for the quenching fixture design.
이경훈(K.H. Lee),고대철(D.C. Go),김상주(S.J. Kim),김병민(B.M. Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
This paper presents a study on micro forming technologies for micro-electro-mechanical systems(MEMS) parts such as micro gears below 450㎛ in diameter and 38 in module. For this purpose, it is important to develop new methods to fabricate micro gears and choose suitable materials for micro forming. Generally micro gears made by MEMS process butin this study micro gears made by extrusion process using micro dies. Photochemically machinable glass has been used to fabricate micro dies by photo-lithography and anisotropic etching techniques. A new forward extrusion machine has been developed for this study. LLDPE(Linear Low Density Polyethylene) and EVA(Ethylene Vinyl Acetate) have been used in micro extrusion. Specimens were placed in a container and extruded by a piezoelectric actuator. Micro extrusion has succeeded in forming micro-gear shafts.
소형 헬리컬 기어 압출 시 Zn-22wt%Al 합금 분말의 강화방법에 따른 미세 조직 변화에 관한 연구
이경훈(K.H. Lee),이정민(J.M. Lee),고대철(D.C. Ko),김병민(B.M. Kim) 한국소성가공학회 2011 압출 및 인발 심포지엄 Vol.2011 No.8
The extrusion with different powder consolidation methods, which is based on the superplastic behavior of the Zn-22wt%Al alloy powder, is proposed to observe the microstructure of helical gears and extrudability. The specifications of the helical gears were as follows: m, 0.3; Z, 12; Dp, 3.727mm; and β, 15˚. Compacted powders were consolidated by solution treatment, dwelling & quenching and sintering. The consolidated billets consisted of equiaxed fine grained structure, lamellar structure and mixed phase. Extrusion experiments were carried out under the following conditions: temperature, 250˚C and extrusion velocity, 0.1mm/min. The mechanical properties of extruded helical gears were investigated by measurement of Vickers hardness, extrusion load and SEM observation.
초소형 스퍼기어 제조를 위한 초소성 A1-78Zn 분말 압출
이경훈(K. H. Lee),김진우(J. W. Kim),황대원(D. W. Hwang),김종현(J. H. Kim),장석상(S. S. Chang),김병민(B. M. Kim) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.10
This study was designed to fabricate the micro-electro-mechanical systems (MEMS) parts such as micro spur gears using hot extrusion of gas atomized Al-78Zn powders. For this purpose, it is important to develop new methods to fabricate micro-dies and choose suitable extrusion conditions for a micro-forming. Micro-dies with Ni were fabricated by LIGA technology. LIGA technology was capable to produce micro-extrusion dies with close tolerances, thick bearing length and adequate surface quality. Superplastic Al-78Zn powders have the great advantage in achieving deformation under low stresses and exhibiting good micro formability with average strain rates ranging from 10<SUP>-3</SUP> to 10<SUP>-2</SUP> s<SUP>-1</SUP> and constant temperatures ranging from 503 to 563K. Al-78Zn powders were compacted into a cylindrical shape (Φ3xh10) under compressive force of 10kN and, subsequently, the compacted powders were extruded at 563K in a hot furnace. Micro-extrusion has succeeded in forming micro-gear shafts.