Apparatus and method for electrochemical corrosion monitoring
AssigneeKatholieke Universiteit Leuven
InventorsRik-Wouter Bosch, Walter F. Bogaerts
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Abstract
A method and apparatus are provided for monitoring a corrosion current density to determine a corrosion rate of a corroding system 130 using Electrochemical Frequency Modulation (EFM). In the method two sinusoidal signals 100, 105, having different frequencies are applied to a portion of the system 130 to distort a response current 120 in the system. Analysis of this current 120 generated in response to the applied perturbation signal 110 provides the corrosion rate and Tafel parameters of the system 130 without prior knowledge of the Tafel parameters. In one embodiment, the method and apparatus also provide a mechanism for validating the quality of the measured data used in calculating the corrosion rate and Tafel parameters.
Claims17
A method of monitoring a corrosion current density to determine a corrosion rate of a corroding system, the method comprising steps of:
- (a) applying two sinusoidal signals having different frequencies to a portion of the system, the two sinusoidal signals have angular frequencies ω1 and ω2;
- (b) measuring a response current in response to the sinusoidal signals;
- and
- (c) analyzing the response current measured at zero, harmonic and intermodulation frequencies to obtain the corrosion rate by:
- (i) transforming the response current from a time domain to a frequency domain;
- and
- (ii) calculating the corrosion current density (icorr) using the following equation:
- i corr = i ω1ω2 2 2 i ω2 ± ω1 .
A method of validating data measured to determine a corrosion rate of a corroding system, the method comprising steps of:
- (a) applying two sinusoidal signals having different frequencies to a portion of the system;
- (b) measuring a response current in response to the sinusoidal signals at harmonic and intermodulation frequencies;
- (c) calculating a causality factor using the response current measured at an intermodulation frequency and at a harmonic frequency of one of the two applied sinusoidal signals;
- and
- (d) comparing the causality factor to a predetermined value to validate the response current measured.
A computer program for monitoring a corrosion current density to determine a corrosion rate of a controlled corrosion system, the computer program comprising:
- (a) a sinewave-generator module configured to generate and apply at least two sinusoidal signals having different frequencies to a portion of the system;
- (b) a measured-waveform module configured to measure voltages of the sinusoidal signals and a response current generated in the system in response to the sinusoidal signals;
- (c) a frequency-response-magnitude module configured to transform the measured response current from a time domain to a frequency domain;
- and
- (d) a frequency-response-analyzer module configured to analyze the response current measured at zero, harmonic and intermodulation frequencies of the sinusoidal signals to obtain the corrosion rate.
Dependencies are inferred from the claim text.