| 摘要 |
PURPOSE:To measure a corrosion rate of equipment in a nondestructive manner, by calculating the amount of corrosion of metal according to a chart showing a relationship between the amount and time of corrosion of metal in a solution predetermined and according to a relationship between a diffusion impedance factor and the amount of corrosion. CONSTITUTION:Metal desired to measure a corrosion rate and an electrode set as opposed to the metal are immersed into an electrolyte solution and an AC voltage with a specified frequency is applied to measure current flowing between the metal and the electrode. From the current value, a chart is determined to show a relationship between the frequency of the AC voltage applied and a real number part impedance and false number impedance. According to the chart, a parameter is determined comprising a reaction resistance Ra of the metal, a reaction resistance Rc of the electrode, a solution resistance Bsol, a film resistance Rf of a film formed on the metal surface, a film capacitance Cf of the film, an electric double layer capacitance Cdl and a diffusion impedance factor sigma obtain from a diffusion resistance oxygen ions diffusing in the film. Then, the amount of corrosion of the metal is calculated according to the chart showing a relationship between the amount and time of corrosion of the metal in the solution predetermined and according to that between the factor sigma and the amount of corrosion.
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