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증착 후 열처리온도에 따른 SnO2 박막의 수소 검출민감도 변화
유용주 ( Y Z You ),김선광 ( S K Kim ),이영진 ( Y J Lee ),허성보 ( S B Heo ),이학민 ( H M Lee ),김대일 ( Dae Il Kim ) 한국열처리공학회 2012 熱處理工學會誌 Vol.25 No.5
SnO2 thin films were prepared on the Si substrate by radio frequency (RF) magnetron sputtering and then post deposition vacuum annealed to investigate the effect of annealing temperature on the structural properties and hydrogen gas sensitivity of the films. The films that annealed at 300℃ show the higher sensitivity than the other films annealed at 150℃. From atomic force microscope observation, it is supposed that post deposition annealing promotes the rough surface and also, increase gas sensitivity of SnO2 films for hydrogen gas. These results suggest that the vacuum annealed SnO2 thin films at optimized temperatures are promising for practical high-performance hydrogen gas sensors.
허정(J. Huh),유용주(Y. Z. You) 한국열처리공학회 2002 熱處理工學會誌 Vol.15 No.3
BCl_3를 봉소의 공급원으로 하여 공구강의 표면에 PECVD 방식에 의해 TiBN 박막을 코팅하였다. TiBN박막의 미세조직은 TiN에 비해 상대적으로 치밀하여 Hv 5000이상의 고경도를 얻을 수 있었다. 박막의 경도와 밀착력은 BCl_3양에 따라 증가하여 41/h일 때 최대치를 나타냈는데 내마모성도 이 때가 가장 우수하였다. TiBN 코팅에 의해 금형의 수명을 크게 향상시킬 수 있었고 특히 다이캐스팅 금형에서 그 효과가 크게 나타났다. During warm and hot forging process of steels or aluminum alloys, dies are subject to earty fracture, severe wear by thermo-mechanical stress. Especially, during the die-casting of aluminum alloys, the service life of dies is incredibly lowered. In this study we investigated the characteristics of TiBN films produced by PECVD. TiBN films showed very high hardness, excellent wear resistance, which could enhance the service life of die parts such as forging punch, die casting core pin successfully.
GCD 45 중심부 조직 및 기계적 성질에 미치는 ADI 열처리 조건의 영향
김한군(H . G . Kim),유용주(Y . Z . You),이재식(J . S . Lee),정태영(T . Y . Chung) 한국열처리공학회 2002 熱處理工學會誌 Vol.15 No.1
N/A The effect of ADI heat treatment conditions on the core microstructures and mechanical properties of GCD 45 has been investigated. In the case of 25βÆ in diameter, it has been found that pearlite structure is not obtained, and the matrix is consisted of graphite, bainite and retained austenite. Upon cooling isothermally from 900℃, the core structure of 35 mm in diameter is converted to pearlite. However, the structure is transformed to bainite after slow cooling from 900℃ to 800℃.
허성보 ( S B Heo ),이영진 ( Y J Lee ),김선광 ( S K Kim ),유용주 ( Y Z You ),최대한 ( D H Choi ),이병훈 ( B H Lee ),김민규 ( M G Kim ),김대일 ( Daeil Kim ) 한국열처리공학회 2012 熱處理工學會誌 Vol.25 No.6
SnO₂ thin films were prepared on the Si substrate by radio frequency magnetron sputtering and then surface of the films were irradiated with intense Ar ion beam to investigate the effect of Ar ion irradiation on the properties and hydrogen gas sensitivity of the films. From atomic force microscope observation it is sup-posed that intense Ar bombardments promote rough surface and increase gas sensitivity of SnO₂ films for hydro-gen gas. The films that Ar ion beam irradiated at 6 keV show the higher sensitivity than the films were irradiated at 3 keV and 9keV. These results suggest that the SnO₂ thin films irradiated with optimized Ar ion beam are promising for practical high-performance hydrogen gas sensors.
마이크로 펄스 플라즈마 질화에 의해 생성된 금형 공구강의 표면층에 관한 연구 - 공정 변수의 영향 -
이재식(J . S . Lee),김한군(H . G . Kim),유용주(Y . Z . You) 한국열처리공학회 2001 熱處理工學會誌 Vol.14 No.1
N/A The effects of gas composition, pressure, temperature and time on the case thickness, hardness and nitride formation in the surface of tool steels(STD11 and STD61) have been studied by micro-pulse plasma nitriding. External compound layer and internal diffusion layer and the diffusion layer were observed in the nitrided case of tool steels. The relative amounts and kind of phases formed in the nitrided case changed with the change of nitriding conditions. Generally, only nitride phases such as γ(Fe₄N), ε(Fe_(2-3)N), or Cr_(1.75)V_(0.25)N₂phases were detected in the compound layer, while nitride and carbide phases such as ε-nitride(Fe_(2-3)N), (Cr,Fe)_7C₃or Fe₃C were detected in the diffusion layer by XRD analysis. The thickness of compound layer increased with the increase of nitrogen content in the gas composition. Maximum case depth was obtained at gas pressure of 200Pa.