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NH₃가스 미량첨가 분위기에서의 CO-H₂혼합가스에 의한 과탄화철의 합성
정성실,정우창,강흥원,박응열,정원섭,박익민 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.11
The synthesis process of iron carbide was proceeded in two stages of reduction of hematite fines by H₂ gas, and carburization of the reduced metal by CO-H₂ gas mixture at 600℃. The surface of reduced iron was pre-treated with an addition of 0.05 vol% NH₃-Ar before carburization. The synthesized iron carbides were comprehensively explored by C/S analyzer (Low C/S determinator), Mossbauer spectroscopy, X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy at various reaction times of 5, 10, 15, 20, 25, 30, and 35 min. By addition of a small amount of NH3 gas, the super iron carbides contained 10 wt% carbon were made, and such addition stabilized iron carbides. It was found that addition of NH3 gas played a major role in the formation of iron carbide without decomposition (Fe₃C→ 3Fe+C) of iron carbides and precipitation of free carbon. From these results, we succeed in synthesis of super iron carbide, Fe_(5)C₂, with a stable single phase without Fe and Fe₃C phases. (Received August 2, 2004)
탄소나노튜브 강화 SKD11 냉간금형용 하이브리드 탄소나노소결체 제조 및 특성 평가
정성실,문제세,이대열,윤국태,박춘달,송재선,Jung, Sung-Sil,Moon, Je-Se,Lee, Dae-Yeol,Youn, Kuk-Tae,Park, Chun-Dal,Song, Jae-Sun 한국분말야금학회 2013 한국분말재료학회지 (KPMI) Vol.20 No.4
SKD11 (ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. The CNTs was good additives to improve the mechanical properties of metal. In this study, 1, 3 vol% CNTs was dispersed in SKD11 matrix by mechanical alloying. The SKD11+ CNT hybrid nanocomposites were investigated by FE-SEM, particle size distribution, hardness and wear resistance. The CNT was well dispersed in the SKD11 matrix and the mechanical properties of the composite were improved by CNTs addition. It shows good feasibility as cold work die tool.
용탕단조한 Al / Al2O3 복합재료에서의 예비성형체 변형 및 섬유열처리 영향
지동철,정성실,조경목,박익민,김진 ( Dong Chul Ji,Sung Sill Jung,Kyung Mok Cho,Ik Min Park,Jin Kim ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.1
N/A This study presents the effect of applied pressure on the preform deformation during squeeze casting of Al₂O₃short fiber reinforced aluminum alloy (AC8A) metal matrix composites. A preliminary model based on the general beam theory is suggested for the prediction of the preform deformation. Two different commercially available Al₂O₃ short fiber (Saffil, Kaowool) were used to study the influence of the fibers on the microstructure and mechanical properties of the squeeze cast Al/Al₂O₃composites. The composites were fabricated with the applied pressure of 75㎫ which was found to be the optimum condition for the squeeze casting of the composites in this study. For the amorphous Kaowool fiber, hard crystalline Mullite phase was formed with heat treatment. Both of amorphous and the crystallized Kaowool fibers were used to fabricate Al/Al₂O₃composites. Microhardness of crystallized Kaowool fiber revealed higher than that of the amorphous Kaowool fiber in the squeeze cast composites. It was also found that the wear resistance of Kaowool fiber reinforced composites increased with the amount of Mullite.
방전플라즈마 소결법으로 제조된 탄소나노튜브 강화 SKD11 금형강의 분말소결 특성
문제세,정성실,이대열,정영근,강명창,박춘달,윤국태,Moon, Je-Se,Jung, Sung-Sil,Lee, Dae-Yeol,Jeong, Young-Keun,Kang, Myung Chang,Park, Chun-Dal,Youn, Kook-Tae 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.3
SKD11(ASTM D2) tool steel is a versatile high-carbon, high-chromium, air-hardening tool steel that is characterized by a relatively high attainable hardness and numerous, large, chromium rich alloy carbide in the microstructure. SKD11 tool steel provides an effective combination of wear resistance and toughness, tool performance, price, and a wide variety of product forms. Adding of CNTs increased the performance of mechanical properties more. 1, 3 vol.% CNTs was dispersed in SKD11 matrix by mechanical alloying. SKD11 carbon nanocomposite powder was sintered by spark plasma sintering process. FE-SEM, HR-TEM and Raman analysis were carried out SKD11 carbon nanocomposites.