Method for evaluating effective porosity of metal corrosion product film

Abstract

The invention discloses a method for evaluating the effective porosity of a metal corrosion product film. The method comprises the following steps of: acquiring a corroded metal sample with the corrosion product film; preparing metal replacement solution which can generate replacement reaction together with a metal matrix in the metal sample; immersing the metal sample with the corrosion product film in the metal replacement solution for cleaning, and acquiring the metal sample with the treated corrosion product film; calculating a ratio between a characteristic peak value of a replacement metal X in the treated corrosion product film and a characteristic peak value of the corrosion product, and acquiring a mass fraction of the replacement metal in the treated corrosion product film according to the ratio; and calculating the effective porosity of the corrosion product film. The method disclosed by the invention has the advantages that due to adoption of the technical scheme, the protectiveness of the corrosion product film is evaluated by measuring the effective porosity of the corrosion product film, so that the protectiveness of the corrosion product film is more accurately and more scientifically evaluated and the metal corrosion behavior is realized; the method is simple, easy and low in cost, and is conveniently applied to production and experiment.

Description

technical field [0001] The invention relates to a method for testing and analyzing materials, in particular to a method for evaluating the effective porosity of a metal corrosion product film. Background technique [0002] Materials, energy and information are the three pillars of the development of modern society. As the material basis, materials play an important role in human production and living activities. However, corrosion, as one of the three most common failure modes of materials, has always been a problem that materials have to consider. The corrosion of metal materials is particularly prominent, and about 10 - 20% metal loss. The annual direct economic loss caused by corrosion accounts for about 1% of the gross national product of countries all over the world. - 5% (Ke Wei, China Corrosion Investigation Report, Beijing: Chemical Industry Press, 2003). With the occurrence of the metal corrosion process, a layer of corrosion products is often formed on the meta...

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Problems solved by technology

However, this method measures the porosity of all pores in the corrosion product film. Considering the nature of the electrochemical corrosion process, the porosity measured by this method cannot scientifically evaluate the protection of the corrosion product film, because in the corrosion In the product film, not all the pores that exist can make the corrosive medium contact the metal matrix. Therefore, even if such pores exist in a large number in the corrosion product film, it will not cause further corrosion.

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