http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
표면에너지를 이용한 고규소철 합금의 자기적 특성에 미치는 열처리 영향
구자명,이갑호 ( J . M . Koo,K . H . Lee ) 한국열처리공학회 1996 熱處理工學會誌 Vol.9 No.1
Different crystallographic planes, at a gas-metal interface, have different surface energy. To grow the (100) grains of 6.5wt%Si-Fe alloy preferentially, it was heat-treated in the atmosphere of sulfur by using the surface energy. When the specimen is heat-treated for 1 hour at 1175℃ by using the atmosphere of sulfur produced by heating at 75℃, (100) grains were grown to 3.5㎜. Owing to the growth of (100) grains, the coercive force was decreased to 2.1A/㎜, and the magnetic induction at 800(A/㎜) was increased to 1.61T.
고규소철 강판의 자기적 특성에 미치는 3차 재결정의 영향
구자명 ( J . M . Koo ) 한국열처리공학회 1997 熱處理工學會誌 Vol.10 No.4
The 6.5wt%Si-Fe alloy sheets were made by the twin roll process. The magnetic properties and microstructures of sheets annealed in the sulfur atmosphere were studied. In the as-prepared sheet, nonoriented columnar grains about 10㎛ in diameter were observed, which grew from the surface to the inner part of the sheet. When the annealing temperature was around 700℃, the primary recrystallization was formed around the middle part of the sheet thickness, and the grain size increased with increasing annealing temperature. At the annealing temperature of 900℃, the grain size became 30∼40㎛. Around the annealing temperature, the motive force of the grain growth is the grain boundary energy. However, above 1000℃ the surface energy played an important role in the observed grain growth. When the sheet were annealed at 1200℃, the grains whose (100) planes were paralled to the thin plate surface grew, and all sheet surfaces were covered with these grains after 1 hour annealing. This phenomenon is called tertiary recrystallization. A difference in surface energy between (100) and (110) surfaces provides a driving force for growth of tertiary grains. The coercive force was 0.27 mOe and the AC core loss W_(12/50) was 0.38w/㎏ for the 6.5wt%Si-Fe alloy.
코어금형용강 SKD11의 플라즈마 전해산화에 의한 피막 형성
김상무 ( S. M. Kim ),이태행 ( T. H. Lee ),강석조 ( S. J. Kang ),조영희 ( Y. H. Cho ),구자명 ( J. M. Koo ) 한국열처리공학회 2011 熱處理工學會誌 Vol.24 No.4
Surface coatings were prepared on SKD11 core mold steel by plasma electrolytic oxidation (PEO). The coatings were investigated about the formation condition of core mold steel. SKD11 were coated by PEO in a mix solution of Sodium Aluminate NaAlO2 (10g/l), Sodium Silicate powder Na2SiO3 (0.5g/l), Sodium tungstate dihydrate Na2WO42H2O (0.5g/l) at less than 30℃. The electrical condition were voltage : 500~600V ; Pulse : 600~1800Hz ; current density 15~20A/dm2 ; various time : 3min~40min. The coatings surface morphology, cross-section, friction coefficient, hardness were investigated. The coatings on SKD11 core mold steel by PEO indicated that the extension of service life.
급속응고된 Fe-6.5wt% Si 강판의 미세조직과 자기적 특성에 미치는 열처리의 영향
황돈하,이갑호,이태행,구자명 ( D . H . Hwang,K . H . Lee,T . H . Lee,J . M . Koo ) 한국열처리공학회 1995 熱處理工學會誌 Vol.8 No.2
The alloying of 6.5wt% Silicon in iron decreases the magnetization and the anisotropy and minimizes the iron loss noticeably. But it is very difficult to make thin sheets because of its poor ductility which is due to an ordering reaction (body centered cubic to CsCl type crystal structure). However the ordering reaction can be suppressed by rapid solidification method. The cooling rate of rapidly solidified Fe-6.5wt% Si alloy is about 10³K/s and rapidly solidified structure are fine structure, cellular structure, dendrite and equiaxed grain from surface. The precipitates of DO₃Phase emerges on B₂matrix and the coercive force was 0.51 Oe (50cycle, 15KGauss) in Fe-6.5wt% Si alloy which was processed by heat treatment of 1150℃ for 1hr in high vacuum.