Corrosion pit depth determining method by use of confocal microscope

Abstract

The invention discloses a corrosion pit depth determining method by use of a confocal microscope. The method makes full use of original corrosion information on the surface of a sample, the data source is real and reliable, and the credibility of a determined result is quite high. The method transforms a minimal difficult-to-distinguish corrosion morphology from a macro perspective into a visual and vivid Profile graph of a corrosion pit, such that more complete attention is given to corrosion details, and the accuracy of a measuring result is greatly improved. The method effectively makes up for the disadvantages of poor measuring precision, limited measuring scope and the like of a conventional depth measuring instrument, further enlarges the measuring scope of the corrosion pit, can be used for measuring the depth of the corrosion pit and can also be used for measuring the width of the corrosion pit. The method is simple and convenient to operate, small in consumed time and high in experiment efficiency, thereby being an important experiment means for a sample local corrosion condition evaluation and a local corrosion resistance capability evaluation.

Description

Technical field [0001] The invention belongs to a new experimental technology in the field of material analysis and testing, and particularly relates to a method for measuring the depth of corrosion pits by using a confocal microscope. Background technique [0002] When evaluating the destructiveness of corrosion to metals and estimating the service life of metal components, we often need to study the surface morphology of metal corrosion. The depth of corrosion pits is one of the important parameters that characterize the degree of corrosion of materials. Through the depth of corrosion pits The changes in the sample surface can be analyzed for corrosion. [0003] In the past, when measuring the depth of the corrosion pit, the measuring device of the corrosion pit depth measuring instrument was usually used, which can directly measure the depth of the corrosion pit through the built-in dial indicator. However, there are many problems in the actual use of this instrument, such as t...

AI Technical Summary

Problems solved by technology

However, there are many problems in the actual use of this instrument, such as the size of the probe measured by the instrument is too large, the requirements for the material of the probe are too high, etc. These problems cause certain limitations in the use of this depth measuring instrument

From the perspective of material corrosion, since the corrosion morphology of metal materials is very complex, usually irregular, rough, and concave-convex, it is quite difficult to measure the depth of corrosion pits with this kind of depth gauge; With the increase of time and the prolongation of the corrosion cycle, a large number of residual corrosion products will be blocked in the orifice during the corrosion process, which will cause greater difficulties in the measurement of the depth of the corrosion pit.

[0004] A large number of research documents show that although people have made some improvements to the existing corrosion pit depth measuring instrument in many aspects, such as changing the probe of the dial indicator from a spherical shape to a needle shape as needed, improving the material of the probe to increase the strength of the gauge head etc., but still not well solved the problem that the depth of tiny pitting pits that appear in the metal corrosion stage, especially in the early stage of development, cannot be accurately measured.

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