증착조건과 진공열처리 온도에 따른 ITO/PES 박막의 특성 연구

이재영,박지혜,김유성,천희곤,유용주,김대일,Lee, Jae-Young,Park, Ji-Hye,Kim, Yu-Sung,Chun, Hui-Gon,You, Yong-Zoo,Kim, Dae-Il 한국재료학회 2007 한국재료학회지 Vol.17 No.4

Transparent conducting indium tin oxide (ITO) films were deposited onto the Polyethersulfone (PES) substrate by using a magnetron sputter type negative metal ion source. In order to investigate the influence of cesium (Cs) partial pressure during deposition and annealing temperature on the optoelectrical properties of ITO/PES film the films were deposited under different Cs partial pressures and post deposition annealed under different annealing temperature from $100^{\circ}C$ to $170^{\circ}C$ for 20 min at $3\;{\times}\;10^{-1}$ Pa. Optoeleetrical properties of ITO films deposited without intentional substrate heating was influenced strongly by the Cs partial pressure and the Cs partial pressure of $1.5\;{\times}\;10^{-3}$ Pa was characterized as an optimal Cs flow condition. By increasing post-deposition vacuum annealing temperature both optical transmission in visible light region and electrical conductivity of ITO films were increased. Atomic force microscopy (AFM) micrographs showed that the surface roughness also varied with post-deposition vacuum annealing temperature.

고감도 ZnO 박막센서의 수소가스 검출 특성 연구

공영민,이학민,허성보,김선광,유용주,김대일,Kong, Young-Min,Lee, Hak-Min,Huh, Sung-Bo,Kim, Sun-Kwang,You, Yong-Zoo,Kim, Dae-Il 한국재료학회 2010 한국재료학회지 Vol.20 No.12

ZnO thin films were prepared on a glass substrate by radio frequency (RF) magnetron sputtering without intentional substrate heating and then surfaces of the ZnO films were irradiated with intense electrons in vacuum condition to investigate the effect of electron bombardment on crystallization, surface roughness, morphology and hydrogen gas sensitivity. In XRD pattern, as deposited ZnO films show a higher ZnO (002) peak intensity. However, the peak intensity for ZnO (002) is decreased with increase of electron bombarding energy. Atomic force microscope images show that surface morphology is also dependent on electron bombarding energy. The surface roughness increases due to intense electron bombardment as high as 2.7 nm. The observed optical transmittance means that the films irradiated with intense electron beams at 900 eV show lower transmittance than the others due to their rough surfaces. In addition, ZnO films irradiated by the electron beam at 900 eV show higher hydrogen gas sensitivity than the films that were electron beam irradiated at 450 eV. From XRD pattern and atomic force microscope observations, it is supposed that intense electron bombardment promotes a rough surface due to the intense bombardments and increased gas sensitivity of ZnO films for hydrogen gas. These results suggest that ZnO films irradiated with intense electron beams are promising for practical high performance hydrogen gas sensors.

SCM435 구조용 합금강의플라즈마 질화에 미치는 전처리 ( Q / T ) 의 영향

임영필,박대철,이재식,유용주 ( Young Phil Lim,Dae Chul Park,Jae Sig Lee,Yong Zoo You ) 한국열처리공학회 1998 熱處理工學會誌 Vol.11 No.2

N/A The effects of pre-heat treatment(Q/T) on microstructure and hardness of SCM435 structural steel nitrided by micro-pulse plasma was investigated. The quenching and tempering temperatures for obtaining matrix hardness of SCM435 steel on range of HRC30 to HRC40 desired for machine parts were about 860℃ and 500℃ respectively. The case depth of SCM435 nitrided at 480℃ for 5 hours was independent of pre-heat treatment condition and was approximately 150㎛. However, hardness and compactness of nitrified layer on Q/T treated specimen were more heigher than annealed specimen. The case depth increased linearly with the increase of nitriding temperature, however, the hardness of nitrified layer decreased with the temperature. Phase mixture of γ` -phase(Fe₄N) and ε-phase(Fe₃N) were detected by XRD analysis in the nitrified layer formed at optimum nitriding condition, and only single γ`-phase was detected in the nitrified layer formed at higher nitriding temperature such as 540℃. The optimum nitriding temperature was approximately 480℃ which is lower than tempering temperature for preventing softening behavior of SCM435 matrix during nitriding process and the surface hardness of nitrified layer obtained by optimum preheat treatment condition was about Hv930

RF 스퍼터와 전자빔 조사를 이용한 ITO/Au/ITO 가스센서 제조 및 특성 평가

허성보 ( Sung Bo Heo ),이학민 ( Hak Min Lee ),( Young Jin Lee ),김유성 ( Yu Sung Kim ),채주현 ( Ju Hyun Chae ),유용주 ( Yong Zoo You ),김대일 ( Dae Il Kim ) 한국열처리공학회 2011 熱處理工學會誌 Vol.24 No.2

Single layer Sn doped In2O3(ITO) films and ITO 50 nm/Au 10 nm/ITO 40 nm (IAI) multilayer films were prepared with electron beam assisted magnetron sputtering on glass substrates. The effects of the Au interlayer, post-deposition atmosphere annealing and intense electron irradiation on the methanol gas sensitivity were investigated at room temperature. As deposited ITO films did not show any diffraction peaks in the XRD pattern, while the IAI films showed the diffraction peak for In2O3 (400). In this study, the gas sensitivity of ITO and IAI films increased proportionally with the methanol vapor concentration and an intense electron beam irradiated IAI film shows the higher sensitivity than the others film. From the XRD pattern, it is supposed that increased crystallization promotes the gas sensitivity. This approach is promising in gaining improvement in the performance of IAI gas sensors used for the detection of methanol vapor at room temperature.

탄소환원에 의한 Zircon으로 부터 고순도 Zirconia 제조에 관한 연구

유용주,이재식 울산대학교 1991 공학연구논문집 Vol.22 No.2

감압하에서 지르콘사를 탄소환원하므로 지르코니아의 고순도화에 대한 연구를 하였다. 지르콘과 탄소의 혼합물을 1 Torr의 진공로 중에서 가열함으로써, 지르콘 중의 SiO₂는 SiO(g)로 제거되었으며, 이 SiO(g)는 로의 낮은 온도 구역에서 미세한 백색 무정형 분말인 SiO(s)로 응축되었다. 생성된 지르코니아에는 미량의 탄소, ZrO 그리고 ZrC등이 존재하였으나, 공기중에서 산화 반응후에는 지르코니아 단일상으로 되었다. 단일상 지르코니아는 1500℃, C/SiO₂몰비 1.0 일때 SiO₂의 함유량이 가장 작았다. 이러한 공정의 반응 생성물은 XRD, SEM-EDX 및 습식방법 등에 의해서 분석하였으며, 지르코니아 분말의 순도는 99.8%이었고 결정구조는 단사정이었다. A production technics of high-purity ZrO₂ powder from zircon (ZrO₂· SiO₂) were investigated by carbothermic reduction under reduced pressure. The mixture of zircon and carbon was heated in the range of 1200℃ to 1500℃ in vaccum furnace under the condition of 1 Torr. The reaction product for the process was examined by XRD, SEM-EDX, and chemical analysis. By this techniques, the SiO₂ in zircon was removed as SiO(g). The generation of SiO(g) from a Zircon/Carbon mixture at high temperature to was greatly enchanced by reduction of pressure compared to atmospheric. Zirconia powder contaminated with a small amount of carbon, ZrO, and ZrC was obtained before oxidation reaction. Single-phase ZrO₂ was obtained after oxidation reaction of Zirconia powder when the the C/SiO₂ mole ration in the Zircon/Carbon mixture was 0.5∼2.0. The SiO₂content in ZrO₂ powder was minimized at a C/SiO₂ ratio of about 1.0. The monoclinic phase zirconia powder with a high purity of 99.8% and fine grain size was obtained. The SiO(g) generated in the process condensed as a fine white amorphous powder in the low-temperature zone of the vaccum furnace, having an ultrafine grain size.

EMF 측정법에 의한 Cu-Co-O System의 열역학적 연구

유용주,이재식 울산대학교 1990 연구논문집 Vol.21 No.1

고체 전해질인 (ZrO₂+ CaO)를 사용하여 구성된 다음과 같은 galvanic cell들을 이용한 EMF를 측정함으로써, Cu₂O, CuO, CoO의 Cu₂CoO₃생성에 대한 자유에너지 값을 얻었으며, Cell(1) Ni, NiO/ZrO₂(+CaO)/Cu, Cu₂O Cell(2) Ni, NiO/ZrO₂(+CaO)/CuO, Cu₂O Cell(3) Co, CoO/ZrO₂(+CaO)/Ni, NiO Cell(4) Co, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(5) Cu, Cu₂O, CoO/ZrO₂(+CaO)/Cu,Cu₂O Cell(6) Cu₂O, CoO, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O Cell(7) CuO, Cu₂O, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O 그 결과들은 아래와 같다. △ G˚??, Cu₂O=-40548+17.494 T cal/mole(970-1258K) △ G˚??, CuO=-36062+20.084 T cal/mole(1162-1332K) △ G˚??, CoO=-56680+17.394 T cal/mole(1126-1326K) 그리고 2 CuO+CoO=Cu₂CoO₃반응에 대한 △G˚=-1618+0.9838 T cal/mole(1162-1332K)이며, 계산된 Cu₂CoO₃의 생성에 대한 자유에너지 값은 △G˚, Cu₂CoO₃=-130423+58.542T cal/mole이다. 그리고 Cu₂CoO₃에 대한 Cu₂O와 CuO의 용해도는 매우 작았다. The equilibrium oxygen pressures of the binary and threephase regions [Cu-O], [Co-O], [Cu, Cu₂O, CoO], [Cu₂O, CoO, Cu₂CoO₃] and [CuO, Cu₂O, Cu₂CoO₃]were measured as a function of temperature by the solid oxide electrolyte (ZrO₂+ CaO) electromotive force method. The galvanic cells used were as follow: Cell(1) Ni, NiO/ZrO₂(+CaO)/Cu, Cu₂O Cell(2) Ni, NiO/ZrO₂(+CaO)/CuO, Cu₂O Cell(3) Co, CoO/ZrO₂(+CaO)/Ni, NiO Cell(4) Co, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(5) Cu, Cu₂O, CoO/ZrO₂(+CaO)/Cu, Cu₂O Cell(6) Cu₂O, CoO, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O Cell(7) CuO, Cu₂O, Cu₂CoO₃/ZrO₂(+CaO)/Cu, Cu₂O The results were expressed by the following equations: G˚??, Cu₂O=-40548+17.494 T cal/mole(970-1258K) G˚??, CuO=-36062+20.084 T cal/mole(1162-1332K) G˚??, CoO=-56680+17.394 T cal/mole(1126-1326K) The measured Gibbs energy of the reaction 2 CuO+CoO=Cu₂CoO₃was found to be -1618+0.9838 T cal/mole(1162-1332K). The evaluated Gibbs energy of formation of △G˚, Cu₂CoO was found to be -130423+58.542T cal/mole. The solubility of Cu₂CoO₃in Cu₂O or CuO is very small.

浮選에 있어서 銅電解法에 依한 亞鉛鑛 活性化에 關하여

郭彰燮,吳在賢,柳龍柱 연세대학교 산업기술연구소 1978 논문집 Vol.8 No.1

The activation of sphalerite with electrolytically generated copper ion from a copper electrode instead of the usual practice of the addition of copper sulphate was studied in the laboratory. A large surface area of copper was provided by lining four sides of a flotation cell with copper sheeting. The lining was connected to the positive terminal of a 12V d.c. battery and the pulp recirculation well to the negative terminal. Sphalerite was effectively activated by this arrangement. Since the quantity of copper used in electrolytic generation was only about 79g/ton when compared with about 204g/ton in the case of copper sulphate, it established that considerable economy can be effected by replacing the use of copper sulphate by electrolytically generated copper ions. Inspite of the high anodic and cathodic current density (Dд was 100-300 A/㎡, Dк was 1000-5000 A/㎡), the electrolytically generated copper ions were not precipitated on the cathode surface.

SCM 435 구조용강의 플라즈마 질화에 관한 연구

유용주,김인수,이재식 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 연구는 SCM 435 구조용강을 450∼650℃의 온도범위에서 NH₃가스유량을 0.5∼2.1 l/min로 변화시키고, 20∼110분 동안 플라즈마 질화처리하여 강 표면에 생성된 경화층의 두께와 경도 및 조직을 조사하였다. 반응온도 550℃, NH₃1.65 l/min.에서 110분 동안 질화 하였을 경우 생성된 질화층의 두께는 260㎛으로써, 화합물층은 16㎛ 이며, 확산층은 224㎛로 이것이 최대의 질화층이었다. 한편, 반응온도 600℃, NH₃1.65 l/min. 가스유량에서 50분간 반응하였을때 24㎛의 최대 화합물층을 얻을 수 있었다. 또한 화합물층은 450℃와 500℃에서는 r'- Fe₄N-α-Fe로, 550℃에서는 r'-Fe₄N+ε- Fe₃N으로, 600℃이상에서는 r-Fe₄N+α-Fe로 구성되어있는 혼합상이었다. 550℃,NH₃1.65 l/min. 에서 80분 동안 질화처리하였을때 생성된 질화층의 최대 표면경도는 Hv 988이었다. The plasma nitriding of SCM 435 structural steel has been studied at the temperature between 450℃ and 650℃ with gas flow rate of NH₃ 0.5 to 2.1 l/min. for 20 to 110 minutes. The phases of compound layer formed below 500℃ and above 600℃ was mixture of r'-Fe₄N and ε- Fe₂₄N phases, while the phases formed 550 was r' - FeN and - Fe N phases. The hardness of nitrided layer formed at 550℃ with gas flow rate of NH₃ 1.65 l/min. for 80minutes was Hv 988. The thickness of nitrided layer formed at 550℃ with gas flow rate of NH 1.65 l/min. for 110minutes was 260㎛. The nitriede layer was composed of 16㎛ compound layer and 244㎛ diffusion layer.

플라즈마 질화법에 의한 SUS316L 스테인레스강의 표면경화에 관한 연구

박정환,김영홍,유용주 울산대학교 1994 공학연구논문집 Vol.25 No.2

본 연구는 SUS316L 스테인레스강을 이용하여 500℃∼600℃의 온도범위에서 NH₃가스의 유량을 0.5∼2.1ℓ/min로 변화시키고, 20∼110분 동안 플라즈마 질화처리하여, 강 표면에 생성된 경화층의 두께와 경도 및 조직을 조사하였다. 반응온도 550℃, NH₃가스의 유량 2.1ℓ/min에서 110분 동안 질화 하였을 경우 생성된 질화층의 두께는 약57㎛로 최대치를 나타내었다. 그리고 질화처리 한 시편을 XRD 분석한 결과 생성된 질화층은 CrN+r-Fe₄N+Fe₃N으로 구성되어 있는 화합물층 이었으며, 확산층은 생성되지 않았고, 생성된 질화층의 경도의 최고치는 약 Hv 1800 이었다. 플라즈마 질화법에 의한 SUS316L 스테인레스 강의 표면경화의 최적조건은 550℃, 2.1ℓ/min. NH₃가스, 110분이었다. A nitrided layer on SUS316L stainless steel by plasma nitrised for back ferrule in one parts of tube fitting has been studied. Specimen was nitrided over 500℃ to 650℃ reaction temperature range with 0.5 to 2.1 ℓ/min. NH₃gas flow rate for 20 to 110 min. The thickness of nitrided layer showed maximum value about 57㎛ at 550℃ reaction temperature and with 2.1ℓ/min. NH₃gas flow rate for 110 min. The result of XRD, nitrided layer was mainly composed of CrN+r-Fe₄N+Fe₃N, but not detected diffusion layer. And also, when NH₃gas flow rate 2.1ℓ/min. , the maximum hardness value of nitrided layer was revealed about Hv 1800 at 550-600℃ reaction temperature range. In this study, the optimum condition of nitrided on SUS316L stainless steel was observed at 550℃ reaction temperature and 2.1ℓ/min. , NH₃gas flow rate for 110 min.

마이크로 펄스 플라즈마 질화법에 의한 선박엔진용 부품의 표면경화에 관한 연구

이재식,유용주 울산대학교 1996 공학연구논문집 Vol.27 No.2

본 연구는 마이크로 펄스 플라즈마 질화처리한 FCD60, S53C, SCM440강재를 고주파 유도경화 열처리한 동일 강재와의 비교분석을 통해 강 표면에 생성된 경화층의 두께와 경도 및 조직을 조사하고 마모시험을 행하였다. Hv550의 유효경도를 갖는 경화깊이는 마이크로 펄스 플라즈마 질화의 경우 FCD60, S53C, SCM440에서 각각 30㎛,25㎛,25㎛이었고, 고주파 유도경화 열처리는 각각 1.4mm이었다. 경화층의 XRD분석결과 마이크로 펄스 플라즈마 질화의 경우 FCD60과 S53C는 주로 r'- Fe₄N, SCM440은 r' - Fe₄N과 ε- Fe₃N의 혼합상이 생성되었으며, 고주파 유더경화 열처리된 경화층은 α- Fe로 모재와 같았다. 또한, 마모시험결과 상온에서는 고주파 유도경화 열처리에 의해 생성된 경화층이 내마모성이 좋으나, 고온(150℃)과 윤활상태에서는 마이크로 펄스 플라즈마 질화처리하에 의하여 생성된 질화층의 내마모성이 우수하였다. The case hardening of FCD60, S53C and SCM440 by micro-pulse plasma nitriding and high frequency induction heat treatment was invesigated. The effective case depth (of which hardeness is over Hv550) of FCD60, S53C and SCM440 nitrided by micro-;ulse plasma method was 30, 25 and 25㎛, respectively. XRE analysis of nitrided layer, showed that mixture of r' - Fe₄N and ε- Fe₃N phases formed on SCM440, r' -Fe₄N single phase formed on S53C and FCD60. In case of hihh frequency induction heat treatment, hardened layer was α - Fe single phase. The hardened hayer formed by high frequency induction heat treatment was more resistant to wear than nitrided layer at room temperature, however nitrided layer by micro-pulse plasma nitriding was more resistant to wear than induction hardened layer at high temperature and lubricated condition.