| Abstract |
| In order to develop a new corrosion sensor for detecting and monitoring the corrosion of buried pipeline, sensor element design and the correlation of its output to corrosion rate of steel pipe itself were evaluated by laboratory test methods in synthetic groundwater. It uses well-known principles of galvanic corrosion and consists of two dissimilar metals (anode and cathode) installed on the buried pipeline. In this paper, two types of electrochemical probes were used: galvanic cells containing pipeline steel (CS)-copper (Cu) and pipeline steel (CS)-type 304 stainless steel (SS) couples. The corrosion behavior in synthetic groundwater for the different electrodes was investigated by potentiodynamic test. The galvanic corrosion test was accomplished by a zero resistance ammeter technique. Weight loss measurements were conducted to obtain the corrosion rates of pipeline steel in synthetic groundwater. The correlation between galvanic current and corrosion rate was obtained by galvanic current measurement and corrosion rate measurements. The results of the potentiodynamic test indicated that copper exhibited an active corrosion behavior, while stainless steel demonstrated spontaneous passivation. In galvanic corrosion tests, the galvanic current of copper-steel couple was higher than that of other couple. The comparison of the sensor output and corrosion rate revealed that a linear relationship was found between the probe current and the corrosion rate. Especially, a better linear quantitative relationship was found between the Cu-CS probe current and the weight loss data of the pipeline steel coupons. In addition, the Cu-CS probe is more suitable for high resistance soil than SS-CS probe, due to the high current output. |
|
|
| Key Words |
| Galvanic couples, Corrosion sensor, Pipeline, Galvanic current, Stainless steel, Copper |
|
|
 |
|
