• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.545-551
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• 2011

Recently, demands for generating high quality tap waters are increasing with high concern of water pollution and corrosion of water pipelines. For the reasons, developing water quality stabilization technique in water purification system is sought rather than replacing to a new pipelines. In this study, high-purity liquid lime($Ca(OH)_2$) was introduced for a water quality stabilization technique in water purification process and simulated water distribution system of pilot-scale size was applied to evaluate anti-corrosion control effect. The effect of anti-corrosion control was calculated in terms of LSI(Langelier Saturation Index) In conclusion, the result of pilot plant showed improvement of corrosiveness by liquid lime($Ca(OH)_2$) with reduction of released iron(Fe). Application of anti-corrosion control technique to the mild steel coupon and the copper coupon were effective by indicating 35.4, 44.5% of improvements. Besides, sample pipes which were treated with liquid lime had formated more thicker layer of corrosion product inside of pipes. As a result, the process of injecting water stabilizer can greatly contribute to the high quality of tap water.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.2
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• pp.215-223
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• 2006

The internal corrosion of water distribution systems is the main cause for the problem of the public health threat as well as water leakage in the damaged pipeline, red water, and odor and taste of the tap water. This study was examined the effect of chemicals used for pH and alkalinity control and corrosion inhibitors for producing the optimal corrosion control method. Corrosion study at different pH and alkalinity indicated that these control using alkaline chemicals was effective in corrosion rate, Fe release reduction, but examined to be increased in turbidity and corrosion-by-products(TTHMs) problems. The turbidity was slightly increased, requiring caution in controlling corrosion with $Ca(OH)_2$. At pH 9.0, TTHMs concentration is increased two times corn pared with non-control of pH. Using the pipe which had experienced 28 years of exposure, iron release was decreased with the corrosion inhibitor. Consequently, pH, Alkalinity control method using alkaline chemicals must be complemented by corrosion inhibitor application for efficient corrosion control.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.661-669
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• 2000

This research was carried out to evaluate effect of metallic release and change of water corrosive indices by the pH and alkalinity adjustment using the SDLS (Simulated Distribution Loop System) which consist of six types of pipe loop with DCIP, PVC, PE, STS304, CP, GSP, respectively, and its effects on water quality changes which were microbes quality(SPC), residual chlorine. THMs and other parameters. And it was to propose optimal criteria of water quality control for the field application. According to the results, water control system by pH and alkalinity adjustment showed the changing of corrosive water and reducing of metallic release rate and it was not affects of THMs formation, microbes regrowth and variation of other parameters. Water quality stability and corrosion control were due to calcium carbonate precipitation film formation of pipe inner by water quality control. Therefore, corrosive water control system by pH and alkalinity adjustment can be attributed to effective water quality management in water distribution system according to water quality stability of pH and TIC(Total Inorganic Carbonate concentration) that affect the precipitation and dissolution of solids.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.97-106
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• 2012

To investigate the application of corrosion inhibitor on water supply pipes, turbidity, magnitude of corrosion, composition of scale and concentration of metals from an old steel pipe were analysed under inhibitor addition. The concentration of turbidity, iron and copper from the pipes under inhibitor application was 12 ~ 14% of the case which no inhibitor was applied, which suggests the application of inhibitor was very effective for internal corrosion control. In addition, SEM, EDX, XRD and XRF test results showed that application of inhibitor was effective for the decrease of iron concentration and increase of oxygen, phosphorus and calcium concentration, which suggested the existence of protective layer. Therefore, the occurrence of red water will be significantly decreased when inhibitor was applied to the old steel pipes.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.193-199
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• 2011

A method to improve internal corrosion control efficiency by adding lime and carbon dioxide, which, in turn increases the Langelier Index (LI) for filtered water at a conventional drinking water treatment plant (WTP) was investigated. The SJ WTP (Q=100,000 $m^{3}$/d) has been operating an internal corrosion control system since 2006. The system has achieved stable operation through technical development and trial and error over a period of several years. As a result of the operation, the LI of treated water has increased up to 29% by adjusting pH of filtered water to 7.8 with the addition of lime and carbon dioxide. Coupon tests in the distribution system indicated that the corrosion rate has been delayed by 24% when the internal corrosion method was implemented. The increase of LI by lime and carbon dioxide has been proven to be a practical method for controlling corrosion.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.839-846
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• 2011

To investigate corrosivity characteristics of raw water in Korea, Langelier index (LI) of 30 multi-regional water treatment plants (WTPs) were evaluated. Annual average values of LI at 30 WTPs were all negative, which means raw water in Korea is very corrosive. LI results for 4 major rivers showed that raw water from Han and Nakdong had relatively high values compared to those of Sumjin and Keum. On the other hand, LI values of raw water from the tributaries of four major rivers were relatively low presumably due to geological characteristics, and in some cases the values were less than -4.0 which means increase of LI is urgently needed to minimize red water problem. Based on the correlation results among LI and water quality parameters, pH, water temperature, calcium concentration were confirmed as major components for LI. Therefore, pH and calcium concentration control is an effective method for the improvement of LI in water treatment processes.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.731-739
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• 2011

To investigate corrosivity characteristics of tap water in Korea, Langelier index (LI) of 30 multi-regional water treatment plants (WTPs) were evaluated. Weekly LI values of 30 WTPs were all negative, which means tap water in Korea might be very corrosive. Maximum LI decrease through water treatment processes was 0.95 under no additional corrosion control process. Based on the correlation results between LI and tap water qualities, pH and calcium concentration were confirmed as major parameters for LI control. Addition of calcium hydroxide with $CO_{2}$ or calcium hydroxide or sodium hydroxide can be chosen based on water quality. Continuous monitoring of LI and related parameters is recommended in water distribution system.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.37-38
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• 2011

알루미늄은 높은 내부식성과 우수한 물리적 특성으로 철강 제품의 부식방지를 위한 표면처리와 항공 우주분야 소재로 각광을 받아왔다. 알루미늄을 철강 제품의 부식방지를 위한 표면처리 소재로 사용되는 경우 비교적 두껍게(15 ${\mu}m$ 이상) 코팅된다. 본 연구에서는 얇은 두께(3 ${\mu}m$ 이하)의 알루미늄 박막을 이용하여 높은 내식성을 갖는 코팅 공정을 개발하고자 한다. 물리기상증착으로 코팅되는 대부분의 금속은 주상정 구조를 갖는다. 주상정 구조는 grain boundary에 공극이 존재하고, 이 공극을 통해서 부식을 일으키는 물질이 보호막과 모재의 계면으로 침투하여 모재가 부식을 일으킨다. 스퍼터링 공정을 제어하여 알루미늄 박막의 공극 발생을 억제하여 보호막으로서의 기능을 향상할 수 있는 방법을 제안한다. 알루미늄 코팅을 위해서 magnetron sputtering을 이용하였으며, 기판은 냉연강판을 사용하였다. 냉연강판위에 코팅된 알루미늄 박막을 분석한 결과, 스퍼터링 소스에 역방향 자기장을 인가하여 코팅한 알루미늄 박막이 염수분무 120 시간 후에도 적청이 발생하지 않는 우수한 내식성을 보였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.504-504
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• 2011

최근 디지털 프린팅 기술의 핵심기술로 떠오르고 있는 잉크젯 프린팅 기술은 최근 기존의 문서인쇄 뿐 아니라, 직물 인쇄, 태양전지 등의 다양한 반도체 소자 제조에 널리 활용되고 있으며, 점차 그 응용 분야를 넓혀가고 있다. 특히 thermal 방식의 잉크젯 피린팅 기술은 etching, thin film process, lithography등의 반도체 공정 기술을 이용하여 제작할 수 있기 때문에, 현재 잉크젯 프린팅 기술은 대부분 thermal 방식을 체택하고 있다. 이러한 thermal 잉크젯 프린팅 방법에서는 잉크를 토출시키기 위하여, 전기적 에너지를 열에너지로 전환하는 전자저항막층이 필수적으로 필요하게 되는데, 이러한 전자저항막층은 수백도가 넘는 고온 및 잉크와 접촉으로 인한 부식 및 산화 문제가 발생할 수 있는 열악한 환경에서 사용되므로, Ta, SiN과 같은 보호층을 필수적으로 필요로 한다. 그러나 최근 잉크젯 프린터의 고해상도 고속화, 대면적 인쇄성 등과 같은 다양한 요구 증가에 따라, 잉크젯 프린터의 저전력 구동이 이슈로 떠올라 열효율에 방해가 되는 보호층을 제거할 필요성이 제기되고 있다. 지금까지는 Poly-Si, $HfB_2$, TiN, TaAl, TaN _0.8 등의 물질들이 잉크젯 프린터용 전자저항막 물질로 연구되거나 실제로 사용되어져 왔으나, 이러한 물질들을 보호층을 제거하는 경우 쉽게 산화되거나, 부식되는 문제점을 가지고 있다. 따라서, 기존 전자저항막의 기능을 만족시키면서, 산화나 부식에 대한 강한 내성을 가져 보호층을 제거하더라도 안정적으로 구동이 가능한 하이브리드 기능성(히터 + 보호층)을 가지는 잉크젯 프린터용 전자저항막 물질의 개발이 시급한 실정이다. 본 연구에서는 자기조립특성을 가져 정밀제어가 가능한 원자층증착법(Atomic Layer Deposition)을 이용하여 원자/나노 단위의 미세 구조 컨트롤을 통해 내열 내산화 내부식성 저온도저항계수를 동시에 가지는 다기능성 전자저항막을 설계 및 개발하고자 하였다. 전자저항막 개발을 위하여 우수한 내부식 내산화성을 가지고 결정립 크기에 따른 온도저항계수 조절이 가능한 platinum group metal들과 전기 저항 및 내열성 향상을 위한 물질의 복합구조막을 원자증증착법으로 증착하였다. 또한, 전자저항막 증착시 미세구조와 공정 변수가 내부식성, 내산화성, 그리고 온도저항계수에 미치는 영향을 체계적으로 연구하여, proto-type의 inkjet printhead를 구현하였다.

• Nuclear industry
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• v.7 no.12 s.58
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• pp.31-35
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• 1987

최근 Ringhals 2호기는 baffle Jetting에 의한 연료손상과 연료내부의 코발트에 의해 문제를 겪었으나, 운전경험으로 고 수소이온농도 (고 리튬농도)의 효과가 입증되었다. 현재 3기의 Ringhals경수로에서는 고 수소이온농도방법이 채택되어, 종사원 피폭의 주 원인인 방사화 부식생성물의 축적을 제어할 수 있음을 보여주고 있다. 다음은 Nuclear Engineering International지 '87년 10월호에 게재된 내용을 번역한 것이다.