In this thesis, using the 400 series ferrite stainless steel such as 434LD2 which are furter excellent then the existing ferric products in mechanical characteristics, and experiment has been conducted on corrosion resistance of sensor ring. The results are following. 1. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition. 2. 434LD2 ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 3. As hardness value of HRB 80 and tensile test, 434LD2 ferrite stainless steel with show a good endurance when it is combined to constant velocity joint (c/v joint), and has a good hardness properties endurable to sand and pebble impact.

In this paper, sensor ring for antilock brake system was studied using the 400 series ferrite stainless steel powder. Because of more excellent corrosion resistance and mechanical characteristics than iron, sensor ring has been manufactured by P/M(Powder Metallurgy) method 400 series ferrite stainless steel. the results are following. 1, Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 2. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.

The present study aims to propose a corrosion detection method using a optical fiber sensor coated with a thin iron film. To evaluate the detection accuracy using the proposed method, 2 typed iron film with thicknesses of 100, 200 nm were used to monitor the reflectivity from corroded iron film via light source injection and the measurement was conducted in air, salt water, mortar packed conditions. As a result, it was found that the thickness of iron film is more sensitive to change in the reflectivity than the variation of exposure conditions

The main cause of corrosion in reinforced concrete is diffusion of degradation factors such as chloride ions, carbon dioxide, and sulfate ions. To monitor the extent of the corrosion in reinforced concrete, it is necessary to recognize and track the diffusion of degradation factors. In this paper, we suggest thin-film iron sensorto measure the penetration of chloride ions. The sensor indicates results as electrical resistance and change in electrical resistance. The sensor and contact pad are connected by an anisotropic conducting film (ACF) bonding in order to reduce the influence of the contact electrical resistance. The sensor’s electrical resistance increases with corrosive behavior and external chloride ion concentration. Use of these thin-film iron sensors enables measurement and monitoring of the depth of chloride ion diffusion in concrete.

A cartridge type sensor head was fabricated to detect the level of corrosion in steel cables with consistent or varying cross sections by assessing the LMA (Loss of Metallic Area) damage. Two coil sensor cartridges were made to cater to cables with up to 70mm and 150mm. The developed system was verified through lab experiment using a tapered steel cable specimen, and through a field test conducted in cable bridge. The result showed that the developed system is capable of assessing a cable with varying cross section.

본 연구에서는 콘크리트내로 침투하는 염소이온을 모니터링하기 위하여, 스크린프리트 기법으로 염소이온 반응형 부식센서를 개발하고, 센서의 세선 수가 부식반응도 및 민감도에 미치는 영향을 실험을 통하여 정량적으로 분석하였다. 개발된 부식센서를 이용하여 염소이온량에 따라 부식 반응도을 확인하였으며, 센서의 파괴정도에 따른 저항변화에서는 단선형 센서보다 다선형 센서에서 큰 저항 변화를 나타내었다. 또한, 부식센서는 NaCl 수용액의 농도가 높은 만큼 센서의 저항변화가 크고, 콘크리트 내에서 센서 종류에 따른 부식저항은 단선형보다 다선형에서 민감도가 높게 나타났으며, 센서의 매설깊이가 클수록 저항변화 사이클 (cycle)은 증가하였다. 이상의 결과로, 본 연구에서 개발된 부식센서는 염분에 대한 부식반응과 민감도, 저항의 변화를 감지할 수 있었으며, 특히 7세선이 우수한 결과를 나타내어, 염분의 침투정도를 모니터링 하는데 가장 적합하다고 판단된다.

콘크리트 내부에 매설된 철근의 부식은 철근콘크리트구조물의 조기 성능저하와 붕괴의 주요원인이 되고 있다. 철근콘크리트 구조물에 발생하는 열화현상 중에서 철근부식에 의해 발생되는 염해는 그 피해가 다른 열화 현상보다 심하고 구조물의 보수 및 시공 측면에서도 막대한 경비가 요구되고 보수시기 또한 정하기 힘들다. 따라서 철근의 부식상태에 대한 조기발견은 관리자의 효율적인 보수 및 보강계획 수립을 위해 매우 중요하다. 한편 철근 부식을 평가하는 방법 중 비파괴측정이 많이 사용되고 있다. 특히 CM-Ⅱ(corrosion meter) 측정기는 자연전위와 분극저항 및 콘크리트 비저항을 측정할 수 있어서 많이 사용되지만 몇 가지 단점을 가지고 있다. 이러한 단점을 극복하기 위해 매립형 미니센서가 개발되어져 왔다. 이 미니센서를 이용하여 철근 부식을 측정한 후 CM-Ⅱ(corrosion meter)의 측정결과와 비교분석하여 개발된 미니센서의 타당성을 검증하였다.