• Corrosion Science and Technology
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• 제17권5호
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• pp.249-256
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• 2018

Metallic structures in the oil and gas production undergo severe degradation due to sweet and sour corrosion caused by the presence of $CO_2$ and $H_2S$ in the fluid environment. The corrosion behavior of 304 austenitic stainless was investigated in the presence of varying concentrations of $CO_2$ or $H_2S$ and $CO_2+H_2S$ to understand the effect of the parameters either individually or in combination. Potentiodynamic polarization study revealed that a small amount of $CO_2$ aided in the formation of calcareous deposit of protective layer on passive film of 304 steel, while increase in $CO_2$ concentration ruptured the layer resulting in sweet corrosion. The presence of $S^{2-}$ damaged the passive and protective layer of the steel and higher levels increased the degradation rate. Electrochemical impedance studies revealed lower polarization resistance and impedance at higher concentration of $CO_2$ or $H_2S$, supporting the outcomes of polarization study. XRD analysis revealed different types of iron carbides and iron sulphides corresponding to sweet and sour corrosion as the corrosion products, respectively. SEM analysis revealed the presence of uniform, localized and sulphide cracking in sour corrosion and general corrosion with protective carbide layer amid for sweet corrosion.

• 한국의류학회지
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• 제25권4호
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• pp.707-718
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• 2001

The purpose of this study is to evaluate a newly developed protective suit with the fragments of grenade. The protection efficiency should be strengthened upon the degree of wound. The fragment weight of the used grenade was measured and the kinetic energy of the maximum speed of the fragments in the field test was 137.7J and this could be the protective efficiency test by the multitude fragments in less than 0.031g of the M16A1. The panel inserted to the new demining suit has protection rate of 100% within the distance of 1m and sample II has protection rate of 100% only beyond the distance of 5m. The test showed that the protection rate on the protective suit of the existing garment was comparatively high, however, the protection rate of the sleeve part was very low. The new demining suit through the research demand some complementary measures to lower the temperatures in ear, average skin temperatures, and the temperatures-humidity inside the clothing for summer climate condition, It showed that 30 minutes of rest on the clothing was difficult to go back to the original condition. But in winter climate condition, there was no problem in the temperature, humidity, and comfort to go back to the original condition during the rest and was better in warmth.

• Tribology and Lubricants
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• 제10권3호
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• pp.29-38
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• 1994

The friction and wear of mild steel at dry sliding surfaces under different vacuum conditions have been investigated to understand the wear mechanisms. For the test, a ball-ondisk typed wear-rig has been built and implemented, allowing control of sliding speed, load and vacuum. Results show that, at a high sliding velocity, friction of low carbon steel (SS41) under a high vacuum is much higher than that of ambient condition and wear is much severer. It is due to lack of effective oxidation film formation on which steel surfaces could protect themselves against the severe wear. It has been shown, however, that there is a critical regime with contact conditions (at a low sliding velocity, a low load, and under a medium vacuum) at which effective, protective films of low carbon steel have been built on the surfaces in a friction process with a self-regulating way, resulting in both very low coefficients of friction (about 0.3) and mild wear. In order to investigate the protective films on steel surfaces, the worn surfaces and the wear debris have been experimentally analyzed with SEM, AES/SAM and XRD. A theoretical analysis of frictional heating at sliding surfaces, and an experimental analysis of the influence of oxidation wear under various vacuum conditions are described. The important variables on which self-formations of protective films at dry sliding surfaces depend, and the wear mechanisms are also investigated.

• 한국재료학회지
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• 제9권5호
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• pp.441-445
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• 1999

Alkaline earth metal oxides were added to the conventional MgO films as a protective layer for dielectric materials to have lower firing voltage(Vf) of the plasma display panel(PDP). Panels with various protective layers of MgO-alkaline earth metal oxides were prepared on glass by using e-beam evaporation and its effect on firing voltage characteristics were investigated. (Ba-Mg)O films had poor voltage characteristics because of higher activation energy of BaO. But, (Sr-Mg)O, (Ca-Mg)O and (Ca-Sr-Mg) O had better voltage characteristics than the conventional MgO. A mixture film of (Mg-Ca-Sr)O show the lowest firing voltage which is less than that of MgO by 20V. The chemical composition to have lowest firing voltage is MgO:SrO:CaO ratio of 6:2:2. The mixture of MgO-Alkaline earth metal oxides films showed good transmittance properties within the visual range.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.185-189
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• 2005

We reported here nano-scale electrical phase-change recording in amorphous $Ge_2Sb_2Te_5$ media using an atomic force microscope (AFM) having conducting probes. In recording process, a pulse voltage is applied to the conductive probe that touches the media surface to change locally the electrical resistivity of a film. However, in contact operation, tip/media wear and contamination could major obstacles, which degraded SNR, reproducibility, and lifetime. In order to overcome tip/media wear and contamination in contact mode operation, we adopted the W incorporated diamond-like carbon (W-DLC) films as a protective layer. Optimized mutilayer media were prepared by a hybrid deposition system of PECVD and RF magnetron sputtering. When suitable electrical pulses were applied to media through the conducting probe, it was observed that data bits as small as 25 nm in diameter have been written and read with good reproducibility, which corresponds to a data density of $1 Tbit/inch^2$. We concluded that stable electrical phase-change recording was possible mainly due to W-DLC layer, which played a role not only capping layer but also resistive layer.

• 전기화학회지
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• 제1권1호
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• pp.55-59
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• 1998

방식도막의 수명에 가장 큰 영향을 미치는 물의 흡수과정을 quartz crystal microbalance법 및 임피던스 원리를 이용하여 연구하였다. 도막에 있어서 물의 흡수량과 전해질 농도 변화에 따른 도막의 capacitance를 조사하였다 방식도막에 대한 물의 흡수는 삼투압 작용에 의해서 이루어지고, 흡수 초기단계에서는 도막두께가 얇을수록 흡수량이 많은 것을 알 수 있었다 그리고 도막을 구성하고 있는 수지의 종류 및 결합 가교밀도에 따라서 흡수성이 큰 영향을 받는다는 것을 알 수 있었다. 또한 방식도막에 있어서는 접촉하는 전해질 용액의 농도 변화에 따라 흡$\cdot$탈수 현상이 발생하였으며, 같은 종류의 도막이라도 도막두께가 얇을수록 탈수현상에 따른 capacitance의 증가폭이 큰 것으로 나타났다

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.33-35
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• 2011

Films of CrAlN and CrZrN were deposited on a steel substrate by closed field unbalanced magnetron sputtering, and their oxidation behaviors were investigated. CrAlN films consisted of dense, polycrystalline CrN and AlN fine columns. The formed oxides consisted primarily of crystalline $Cr_2O_3$ incorporated with $Al_2O_3$. The oxide layers were thin and compact so as to make CrAlN films more protective than CrN films. In case of CrZrN films, Zr atoms were dissolved in the CrN phase. Zr atoms advantageously refined the columnar structure, reduced the surface roughness, and increased the micro-hardness. However, the addition of Zr did not increased oxidation resistance, mainly because Zr was not a protective element. All the deposited films displayed relatively good oxidation resistance, owing to the formation of the highly protective $Cr_2O_3$ on their surface. The $Cr_{40}Zr_9N$ and $Cr_{31}Zr_{16}N$ films oxidized to $Cr_2O_3$ as the major phase and ${\alpha}-ZrO_2$ as the minor one, whereas the CrN film oxidized to $Cr_2O_3$.

• 한국산학기술학회논문지
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• 제20권12호
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• pp.27-36
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• 2019

작은 굴절률 및 높은 굴절률을 갖는 저 분산 렌즈에 대한 요구가 증가함에 따라, 높은 내열성 및 내마모성을 갖는 이형성 보호 필름에 대한 필요성이 증가하고 있다. 그러나 광학 산업은 비구면 유리 렌즈 성형에 사용되는 이형보호 필름의 제조 공정 및 품질 표준에 대한 명확한 표준을 아직 확립하지 못했다. 이 기술은 광학 렌즈를 제조하는 각 회사의 노하우로 취급된다. 본 연구에서는 FCVA (Filtered Cathode Vacuum Arc) 기반 ta-C 박막 코팅의 이온에칭, 각 소스 및 필터부의 마그네트론 및 아크 전류, 바이어스 전압의 최적화에 관한 실험을 수행하였다. 그 결과, 코팅성능 측면에서, 이리듐- 레늄 합금 박막 스퍼터링 제품 대비 필름 두께가 약 50% 얇고, 경도는 약 20%, 박막의 접착강도는 약 40 % 개선된 것으로 측정되었다. 본 연구의 박막 코팅 공정 결과는 금형 이형 박막층의 최소 기계적 특성 및 품질 확립을 위한 유리 렌즈의 개발 및 활용에 크게 기여할 것으로 사료된다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1395-1398
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• 2007

MgO thin films were deposited by e-beam evaporator using the 2-step method for alternate current plasma display panels (AC-PDPs). Glancing angle deposition (GLAD) method was employed to produce various surface geometry of the thin film; the bottom layer was deposited on a substrate by normal e-beam evaporation method and the top layer was deposited on bottom layer with $85^{\circ}$ by GLAD method. Results show that firing and sustain voltages improved as the sharpness of surface and isolated columnar structures increases, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.387-390
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• 2006

The protective layer of AC-PDP was fabricated by laminating an MgO green sheet. The MgO green sheet was made by coating MgO solution composed of solvent, dispersant, binder, and MgO nano-powder. The MgO solution was coated by the die casting method on the base film. We fabricated three kinds of MgO green sheets of which thicknesses were 20, 28, and $40\;{\mu}m$, respectively. The MgO nano-powder showed lower CL intensity and ${\gamma}i$ than the e-beam MgO. The MgO green sheet applied panels showed low luminance and current density. The efficiency was almost same as the conventional e-beam MgO panel.