Field deployable impedance-based corrosion sensor

Electrochemical impedance spectroscopy (EIS) has been used in various applications, such as metal corrosion monitoring. However, many conventional corrosion monitoring setups are bulky and inconvenient for in-situ testing. The purpose of this work is to reduce the size of the whole corrosion monitoring system. We utilized EIS to design a field deployable impedance-based corrosion sensor (FDICS), capable of performing in-situ EIS analysis. Experiments verified the sensor’s accuracy, and the results showed that the sensor performed similarly to a bench-top EIS machine when we tested on circuit models. Furthermore, we used the proposed FDICS to monitor a metal corrosion experiment and performed EIS. The result showed that the proposed FDICS is able to obtain the sample’s impedance spectroscopy, which could help researchers test its corrosion severity on a metallic sample in-situ. Compared to other bulky conventional setups, our device eliminates the design complexity while still showing insights into the corrosion reaction.

Low-Cost Reliable Corrosion Sensors Using ZnO-PVDF Nanocomposite Textiles

Submerged steel pipes are susceptible to corrosion due to long exposure under harsh corrosive conditions. Here, we investigated the reliability and effectiveness of nonwoven zinc(II) oxide-polyvinylidene fluoride (ZnO-PVDF) nanocomposite fiber textiles as an embedded corrosion sensor. An accelerated thermal cyclic method paired to electrochemical impedance spectroscopy (EIS) was used for this purpose. Sensor accuracy and reliability were determined using the textile and instrument as reference electrodes. The results showed that the coating and the sensor improved the corrosion resistance when ZnO was added to the sensor textile and introduced into the coating. As the coating’s glass transition was approached, the corrosion performance of the coating degraded and the sensor accuracy decreased. The results suggested that the flexible sensor is reliable at both monitoring the corrosion and acting as a corrosion barrier.

A Low Cost Sensor System for Monitoring and Predicting Corrosion of Long Term Spent Nuclear Fuel Storage

With the closing of the Yucca mountain storage facility, on-site storage of spent nuclear fuel at reactor sites has increased and will continue to increase until a permanent storage facility is prepared. Dry storage canisters are used to store spent nuclear fuel waste over long periods of time, but are susceptible to mechanical failure via corrosion. This dissertation presents a system to monitor the integrity of the storage canister. Sensor data fusion algorithms have been designed to predict the integrity of the storage system and provide feedback for preventative maintenance. The environmental conditions that lead to corrosion have been replicated and detected by the sensor system within an environmental chamber and the predictive model has been able to estimate the time till failure of a sacrificial corrosion sensor.

An Embedded-Sensor Approach for Concrete Resistivity Measurement in On-Site Corrosion Monitoring: Cell Constants Determination

The concrete electrical resistivity is a prominent parameter in structural health monitoring, since, along with corrosion potential, it provides relevant qualitative diagnosis of the reinforcement corrosion. This study proposes a simple expression to reliable determine resistivity from the concrete electrical resistance (RE) provided by the corrosion sensor of the Integrated Network of Sensors for Smart Corrosion Monitoring (INESSCOM) we have developed. The novelty here is that distinct from common resistivity sensors, the cell constants obtained by the proposed expression are intended to be valid for any sensor implementation scenario. This was ensured by studying most significant geometrical features of the sensor in a wide set of calibration solutions. This embedded-sensor approach is intended to be applicable for RE measurements obtained both using potential step voltammetry (PSV, used in the INESSCOM sensor for corrosion rate measurement) and alternating current methods. In this regard, we present a simple protocol to reliably determine RE, and therefore resistivity, from PSV measurements. It consists in adding a very short potentiostatic pulse to the original technique. In this way, we are able to easy monitor resistivity along with corrosion rate through a single sensor, an advantage which is not usual in structural health monitoring.