Application of electrochemical methods of corrosion rate determination to systems involving corrosion product layers: Part 1: Linear polarization resistance measurement as an example of a simple method that can be performed with commercially available instruments
“…Analogously, in relation with the application of the linear polarisation resistance as a method for determination the corrosion rate of systems coated with layers of corrosion products [31], the results obtained show also to the protective character of the layer formed. The samples heated in the furnace have a linear polarisation resistance smaller than the samples not heated.…”
A composite made from a mixture of iron and copper powders was produced and characterised. The Cu addition favours the production of sintered Fe in the powder metallurgy industry processes. The corrosion behaviour in different electrolytic solution (sodium chloride or hydrochloric, acetic or sulphuric acids) and the corrosion rates were obtained from the weight loss and potentiodynamic methods -intersection and linear polarisation resistance. The values in hydrochloric and sulphuric acid vary slightly with respect to the average value of 78 mV/decade. The values obtained in acetic acid and sodium chloride are higher probably due to the formation of a thin film layer over the metallic surface. The morphology was analyzed through the observation by optical and scanning electron microscopy. It has been determined the nature of the oxide layer, Fe 3 O 4 , by X-ray photoelectron spectroscopy (XPS), isolating the composite from the atmosphere. Thus, this oxide layer acts as a corrosion protective surface.
“…Analogously, in relation with the application of the linear polarisation resistance as a method for determination the corrosion rate of systems coated with layers of corrosion products [31], the results obtained show also to the protective character of the layer formed. The samples heated in the furnace have a linear polarisation resistance smaller than the samples not heated.…”
A composite made from a mixture of iron and copper powders was produced and characterised. The Cu addition favours the production of sintered Fe in the powder metallurgy industry processes. The corrosion behaviour in different electrolytic solution (sodium chloride or hydrochloric, acetic or sulphuric acids) and the corrosion rates were obtained from the weight loss and potentiodynamic methods -intersection and linear polarisation resistance. The values in hydrochloric and sulphuric acid vary slightly with respect to the average value of 78 mV/decade. The values obtained in acetic acid and sodium chloride are higher probably due to the formation of a thin film layer over the metallic surface. The morphology was analyzed through the observation by optical and scanning electron microscopy. It has been determined the nature of the oxide layer, Fe 3 O 4 , by X-ray photoelectron spectroscopy (XPS), isolating the composite from the atmosphere. Thus, this oxide layer acts as a corrosion protective surface.
“…To make sure that the specimens with the same rated corrosion amount share actually identical value, we designed the special equipment, as depicted in Figure 3. The corrosion mass can be calculated by Faraday's Law [45], that is…”
Section: Materials and Manufacture Of Test Samplesmentioning
confidence: 99%
“…To make sure that the specimens with the same rated corrosion amount share actually identical value, we designed the special equipment, as depicted in Figure 3. The corrosion mass can be calculated by Faraday's Law [45], that is where I is the electric current (ampere), t is the time (hours), n =2 is the number of mol participating in production reaction, F is the Faraday constant (96,487 C mol −1 ) and m is the molar mass (55.847 g mol −1 for iron). Figure 3 Arrangement for accelerated corrosion.…”
A non-destructive estimation of the corrosion amount in the existing RC structure is highly desired and therefore this paper presents a proof-of-concept experimental demonstration of such a method, which is based on the eddy heat imaging (EHI) technique. Its basic principle is to convey a corrosion signal to the surface of RC structures by eddy heating. To develop the EHI method, the first key step is to address the question of whether the rate of change in surface temperature is strongly associated with the corrosion amount. In order to make the problem tractable, special equipment was designed, from which 81 observations were obtained for data analysis. After the statistical analysis of the observational data and preliminary application on an in-service bridge, the results show that the EHI method is a promising approach to the quantitative measurement of the corrosion amount of RC structures.
“…At present, electrochemical methods are the main means of assessing the corrosion state of steel reinforcements without removing the concrete cover. In general, the corrosion of steel reinforcement is detected in terms of three measurement parameters, namely (i) half-cell potential, E corr , (ii) concrete resistivity, ρ, and (iii) corrosion current density I corr (ASTM C 876-99 1994, Bungey 1989, Ijsseling 1986, Rodriguez et al 1994, Hansson 1984). The half-cell potential, also called corrosion potential (E corr ), is measured at several distinct points over a given area.…”
Firstly, the fabrication and sensing properties of hybrid carbon fiber reinforced polymer
(HCFRP) composite sensors are addressed. In order to provide a distributed sensing
manner, the HCFRP sensors were divided into multi-zones with electrodes, and each zone
was regarded as a separate sensor. Secondly, their application is studied to monitor the
steel corrosion of prestressed concrete (PC) beams. The HCFRP sensors with different
gauge lengths were mounted on a PC tendon, steel bar and embedded in tensile and
compressive sides of the PC beam. The experiment was carried out under an electric
accelerated corrosion and a constant load of about 54 kN. The results reveal that the
corrosion of the PC tendon can be monitored through measuring the electrical
resistance (ER) change of the HCFRP sensors. For the sensors embedded in tensile
side of the PC beam, their ER increases as the corrosion progresses, whereas for
the sensors embedded in compressive side, their ER decreases with corrosion
time. Moreover, the strains due to the corrosion can be obtained based on the ER
change and calibration curves of HCFRP sensors. The strains measured with
traditional strain gauges agree with the strains calculated from the ER changes of
HCFRP sensors. The electrical behavior of the zones where the corrosion was
performed is much different from those of the other zones. In these zones, either
there exist jumps in ER, or the ER increases with a much larger rate than those
of the other zones. Distributed corrosion monitoring for PC structures is thus
demonstrated with the application of HCFRP sensors through a proper installation of
multi-electrodes.
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