An electrochemical test device for the dynamic process of growth and decline of metal passivation films

Abstract

The invention provides an electrochemical test device for the dynamic process of ebb and flow of a metal passivation film, which belongs to the field of material performance detection. The invention realizes the clamping of the sample and the wear of the passivation film on its surface through the reduction and rotation of the overlapping sand plate groups, so that the test is not affected by the original size of the sample and the size of the wear process within a certain range. Changed restrictions. Through the design of the support plate with the ball bearing structure, the relative position locking and integral rotation between the sand sheets are simultaneously realized. Single or multiple wear tests can be achieved by controlling the frequency and duration of rotating wear. Through the built-in electrochemical three-electrode system, the in-situ, real-time electrochemical test of the dynamic process of passive film growth and growth is realized. Compared with the existing scratch electrode technology, the method of the invention has the advantages of simple principle and simple operation, which increases the effective test area of ​​the sample, and more accurately reflects the wear of the metal passivation film in the high pressure, caustic corrosion environment, or under the condition of frequent wear and tear. and self-healing dynamic electrochemical behavior.

Description

technical field [0001] The invention belongs to the technical field of material performance detection, and in particular relates to an electrochemical test of material corrosion, in particular to a test device for the dynamic process of elongation and growth of a metal passivation film. Background technique [0002] The excellent corrosion resistance of metal materials such as stainless steel and titanium alloys originates from the passivation film on their surfaces. This thin passivation film can provide sufficient protection for the material in its intact state from corrosion by corrosive media. However, when the passivation film is damaged, the local passivation of the material will be destroyed, and a galvanic pair will be formed between the small-area active state and the large-area passivation state, and the electrochemical thermodynamic balance will be broken, resulting in aggravated local corrosion. In high-pressure, low-oxygen deep-sea environments, or other causti...

AI Technical Summary

Problems solved by technology

[0004] The technical task of the present invention is to solve the deficiencies of the prior art, provide an electrochemical test device for the dynamic process of the growth and decline of the metal passivation film, to solve the difficult problem of in-situ wear test of the passivation film of the material in the high-pressure solution environment, and overcome the existing plan The problem of small scratch area and low signal-to-noise ratio of the scratch electrode technology realizes the electrochemical test of the dynamic process of single or multiple wear of the passivation film

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