• 제목/요약/키워드: Sensor Corrosion

검색결과 130건 처리시간 0.031초

부식작용으로 인하여 디스크면으로 이동된 코발트가 Thermal Asperity 현상에 미치는 영향 (The Study of Corrosion Induced Co migration and Its Effect on Thermal Asperity Phenomenon)

  • 좌성훈
    • Tribology and Lubricants
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    • 제15권4호
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    • pp.335-342
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    • 1999
  • Corrosion of the disk has been an ongoing concern for the manufacturers of hard disk drives. With the advent of magnetoresistive (MR) head, very low levels of corrosion and contamination become more critical since the raised defects and corrosion products on the disk surface-anything that heats the MR sensor due to the contact-can distort the output signal of the head. This phenomenon is called as thermal asperity. In this paper, the effect of corrosion as a form of Co migration on the occurrence of thermal asperity in MR drives was investigated. The corrosion test at high temperature (60$^{\circ}C$) and high relative humidity (80%) was emphasized in this study and the testing results at ambient condition were compared. The corrosion on the disks was characterized as the amount of Co ion migration using an ion chromatography (IC) and a time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It is proved that corrosion on the disk surface after storage testing is closely correlated to the amount of Co ions migration from the magnetic layer to disk surfaces and higher Co migration causes more thermal asperities in the drive. In order to reduce Co migration, several methods such as burnishing process and structure of the carbon overcoat were investigated. It is found that the hydrogenated carbon overcoat shows the least Co migration among different types of overcoat layer. However, the most effective way to reduce Co migration is the application of Cr layer between the overcoat and the magnetic alloy layer.

항공기 주기환경이 대기부식위험도에 미치는 영향 (The Effect of Aircraft Parking Environment on Atmospheric Corrosion Severity)

  • 윤주희;이두열;박승렬;김민생;최동수
    • Corrosion Science and Technology
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    • 제20권2호
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    • pp.94-104
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    • 2021
  • Atmospheric corrosion severity associated with aircraft parking environment was studied using metallic specimens, and temperature and humidity sensors installed at each aircraft operating base. Data were analyzed after a year of exposure. Silver was used to measure chloride deposition by integrating X-ray photoelectron spectroscopy depth profiles. Carbon steel was utilized to determine the corrosion rate by measuring the weight loss. The time of wetness was determined using temperature and humidity sensor data. Analysis of variance followed by Tukey's "honestly significant difference" test indicated that atmospheric environment inside the shelter varied significantly from that of unsheltered parking environment. The corrosion rate of unsheltered area also varies with the roof. Hierarchical clustering analysis of the measured data was used to classify air bases into groups with similar atmospheric corrosion. Bases where aircraft park at a shelter can be grouped together regardless of geographical location. Unsheltered bases located inland can also be grouped together with sheltered bases as long as the aircraft are parked under the roof. Environmental severity index was estimated using collected data and validated using the measured corrosion rate.

해양 콘크리트구조물의 철근부식 모니터링을 위한 매크로셀 센서 시스템의 적용 (Application of Macrocell Sensor System for Monitoring of Steel Corrosion in Concrete Structure Exposed to Marine Environment)

  • 이승태;문대중;김완종;문재흠;김학수
    • 한국해안·해양공학회논문집
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    • 제22권4호
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    • pp.241-247
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    • 2010
  • 철근부식은 해양 콘크리트 구조물의 내구성능을 저하시키는 가장 중요한 인자 중 하나이다. 본 논문은 해양환경에 노출된 콘크리트 구조물의 부식거동을 평가하기 위하여 매크로셀 센서 기법 중 하나인 anode-ladder-system의 적용성을 평가한 것이다. 해양환경으로부터 유입되는 염화물의 침투, 확산에 의한 철근부식 위험성에 노출되어 있는 철근콘크리트 구조물의 전위 및 전류를 측정하여 철근의 부식거동을 정성적으로 평가하였다. 부식 모니터링 센서는 평균 해수면으로부터 각각 3.7, 6.0 및 8.2 m 높이에 매설하였으며, 애노드 단자의 부식특성은 평균해수면의 거리에 따라 다르게 거동함을 확인하였다. 또, migration 실험을 통하여 콘크리트 강도와 확산거동과의 관계를 고찰하였다. 결론적으로, 해양 콘크리트 구조물의 부식을 방지 및 완화하기 위해서는 적절한 콘크리트 피복두께의 확보 및 초기 콘크리트의 품질 개선이 중요한 것으로 조사되었다.

전선 부식에 따른 와전류특성 조사 (A Study of Eddy Current Characteristics which Follows in the Corrosion of Power line)

  • 오용철;정한석;이재봉;임주혁;손기정;김진사;김충혁
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.77-77
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    • 2010
  • We used eddy current sensor for diagnosis of power line. The power line according to the cross section has 6~18 element wires. The corrosion of power line was made by sodium hydroxide. The corrosion time of power line was from 18 hours to 27 hours. We obtained physical characteristics from tensile and torsion tests of power line. The eddy current Characteristics of power line according to the corrosion appeared change of amplitude 200 ~ 800 mV.

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Design, calibration and application of wireless sensors for structural global and local monitoring of civil infrastructures

  • Yu, Yan;Ou, Jinping;Li, Hui
    • Smart Structures and Systems
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    • 제6권5_6호
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    • pp.641-659
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    • 2010
  • Structural Health Monitoring (SHM) gradually becomes a technique for ensuring the health and safety of civil infrastructures and is also an important approach for the research of the damage accumulation and disaster evolving characteristics of civil infrastructures. It is attracting prodigious research interests and the active development interests of scientists and engineers because a great number of civil infrastructures are planned and built every year in mainland China. In a SHM system the sheer number of accompanying wires, fiber optic cables, and other physical transmission medium is usually prohibitive, particularly for such structures as offshore platforms and long-span structures. Fortunately, with recent advances in technologies in sensing, wireless communication, and micro electro mechanical systems (MEMS), wireless sensor technique has been developing rapidly and is being used gradually in the SHM of civil engineering structures. In this paper, some recent advances in the research, development, and implementation of wireless sensors for the SHM of civil infrastructures in mainland China, especially in Dalian University of Technology (DUT) and Harbin Institute of Technology (HIT), are introduced. Firstly, a kind of wireless digital acceleration sensors for structural global monitoring is designed and validated in an offshore structure model. Secondly, wireless inclination sensor systems based on Frequency-hopping techniques are developed and applied successfully to swing monitoring of large-scale hook structures. Thirdly, wireless acquisition systems integrating with different sensing materials, such as Polyvinylidene Fluoride(PVDF), strain gauge, piezoresistive stress/strain sensors fabricated by using the nickel powder-filled cement-based composite, are proposed for structural local monitoring, and validating the characteristics of the above materials. Finally, solutions to the key problem of finite energy for wireless sensors networks are discussed, with future works also being introduced, for example, the wireless sensor networks powered by corrosion signal for corrosion monitoring and rapid diagnosis for large structures.

철근 콘크리트 구조물의 부식감시를 위한 센서의 최신기술동향 (Role of Sensors in Corrsoin Monitoring in Concrete Structures : the State of the Art)

  • 하태현;배정효;하윤철;이현구;박경화;김대경
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.223-226
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    • 2004
  • Many extensive researches in the area of sensor's technology for corrosion monitoring in concrete structures have increasingly been carried out in recent years. This paper gives a brief discussion on the principles and usage of the role of sensors involved in both corrosion initiation and propagation steps of reinforcement corrosion monitoring in concrete structures. Special attention was given to the review of various sensing devices, selection of reliable sensing devices for detecting reinforcement corrosion at the particular environment and at the efficiency of the devices used. Various sensing operations in new and existing concrete structures are also described.

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원전 격납건물 라이너플레이트 배면 콘크리트 채움 여부 점검 기술 개발 (Development of Inspection Technique for Filling or Unfilling of Containment Liner Plate Backside Concrete in Nuclear Power Plant)

  • 이정석;김왕배;곽동열
    • 한국압력기기공학회 논문집
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    • 제16권1호
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    • pp.37-41
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    • 2020
  • The Nuclear containment building is a main safety-related structure that performs shielding and conservation functions to prevent highly radioactive materials from leakage to the outside environment in the case of various environmental conditions and postulated accidents. The containment building contains a reactor, steam generator, pressurizer, tank, reactor coolant system, auxiliary system and engineering safety system, and is designed so that highly radioactive materials above the limits specified in 10 CFR 100 do not escape to the outside environment in the case of LOCA(Loss of Coolant Accident) for instance. The containment metal liner plate(CLP) is a carbon steel plate with a nominal plate thickness of 6 mm, which functions as a mold for the wall and dome of the containment building when concrete is filled, fulfills airtightness to prevent leakage of seriously radioactive materials. In recent years, backside corrosion was found on the liner plate in some domestic nuclear power plants. The main cause of backside corrosion was unfilled concrete. In this paper, an inspection technique of assessing filling suitability for CLP backside concrete is developed. Results show that the validity of inspection technique for CLP backside concrete using vibration sensor is successfully verified.

용융아연욕 탕면 높이 측정을 위한 초음파 센서의 사용에 관하여 (On the use of an acoustic sensor for measuring the level of a zinc pot)

  • 박상덕;임태균;이옥산
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.836-839
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    • 1996
  • Throughout CGL (Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, a robot system is developed to automatically collect and remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special robot tools. For the first time the level of zinc pot must be measured and fed back to the robot controller to avoid submersion of the robot hand into the hot zinc pot. In this paper, acoustic distance sensor is tested as a candidate for the pot level sensor in the view point of hot environment. Some considerations on the use of the acoustic distance sensor will be denoted.

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Detection of SCC by Electrochemical Noise and In-Situ 3-D Microscopy

  • Xia, Da-Hai;Behnamian, Yashar;Luo, Jing-Li;Klimas, Stan
    • Corrosion Science and Technology
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    • 제16권4호
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    • pp.194-200
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    • 2017
  • Stress-corrosion cracking (SCC) of alloy 600 and alloy 800 in 0.5 mol/L thiosulfate solution during constant strain was investigated using electrochemical noise (EN) combined with 3-D microscope techniques. The in-situ morphology observation and EN results indicate that the SCC process could be divided into three stages: (1) passive film stabilization and growth, (2) crack initiation, (3) and crack growth. Power Spectral Density (PSD) and the probability distribution obtained from EN were used as the "fingerprint" to distinguish the different processes. During passive film stabilization and growth, the current noise signals resembled "white noise": when the crack initiated, many transient peaks could be seen in the current noise and the wavelet energy at low frequency as well as the noise resistance decreased. After crack propagation, the noise amplitudes increased, particularly the white noises at low and high frequencies ($W_L$ and $W_H$) in the PSDs. Finally, the detection of metal structure corrosion in a simulated sea splash zone and pipeline corrosion in the atmosphere are established.

와전류센서를 이용한 ACSR 전선의 내부부식 검출 (ACSR Inner Corrosion Detection by Eddy Current Sensor)

  • 강연욱;강지원;양병모;정재기
    • 조명전기설비학회논문지
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    • 제12권1호
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    • pp.12-19
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    • 1998
  • 본 논문에서는 와전류센서를 장착하고 전선위를 자동으로 주행하도록 설계된 부식 검출장치를 이용하여 ACSR의 내부부식 검출에 대해서 다룬다. 또한 내부부식의 검출은 비파괴검사로 행해진다. 독특한 ACSR의 구조에 의한 부식현상을 와전류센서를 이용하여 검출하는 경우, 부식은 센서의 임피던스변화로 검출되고 이 현상을 이론적으로 증명한다. 또한 설계된 부식검출장치의 사양과 성능 그리고 실험방법에 대해 논하고, 현장에 적용가능한 실험결과를 얻었다. 이 부식검출장치는 ACSR의 내부부식을 비파괴로 검출할 수 있고 현실적이라는 결론을 얻었다. 피시험체인 도체의 피복여부에 관계없이 이장치는 이용가능하고, 이 장치의 실용화에 의해 선로의 유지보수의 효율을 증대시키고 선로의 향상이 기대된다.

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