Soaking color transferring method for evaluating magnesium, aluminum and alloy corrosion resistance

Abstract

The invention discloses an immersion changing color method for evaluating the corrosion resistances of magnesium, aluminum and the alloy, which is that the magnesium, the aluminum or the alloy is plunged in the corrosion promotion solution according to the volume to area ratio 2-100ml / cm<2 >, the time needed by that the color of the solution transforms completely is observed. The corrosion promotion solution is a water-base solution, wherein, the indicator is KMnO4, whose concentration is 2-500mg / L, the etchant is HNO3, whose concentration counting as the nitric acid with a density of 1.4g / mLis 0.2-50ml / L. The method provided by the invention is easy and feasible, does not need special instrumentation and equipment, overcomes the defects of the existing spot test method, and enhances thesensitivity and the accuracy of the test.

Description

technical field [0001] The invention belongs to the field of material science and technology, in particular to a method for evaluating the corrosion resistance of materials. Background technique [0002] Material performance evaluation plays an important role in the research and development of materials science and technology. The results of material corrosion resistance evaluation are directly related to the direction of process optimization, such as various surface modification technologies with the main task of enhancing material corrosion resistance, including anodic / micro-arc oxidation, chemical conversion, electroless plating, electroplating, etc. All take the corrosion resistance test results as the basis to guide the optimization of process parameters. [0003] There are many methods for evaluating the corrosion resistance of materials, such as ①electrochemical testing techniques such as potentiodynamic polarization, AC impedance spectroscopy, and cyclic voltammetry...

AI Technical Summary

Problems solved by technology

The above testing techniques have their advantages and disadvantages in evaluating the corrosion resistance of materials, but they also have the following main defects: rely on expensive testing instruments / equipment and must have solid professional knowledge, such as ①, ② and ③, of which technology ① The equipment cost is the highest; the test cycle is long, such as the test cycle of ② and ③ is generally more than 24h, and some tests last for several weeks; the analysis of test results is complicated, such as ①

The drop test method is simple and easy to implement, but it also has the following main shortcomings: first, the droplet volume is greatly affected by the liquid taking tool and human factors; second, the corrosive liquid has different effects on different materials or the same material with different surface states. Wettability; thirdly, too small volume of corrosive liquid, changeable material surface color, generation of air bubbles when corrosion occurs, etc. will easily affect the accurate judgment of the tester on the occurrence of "corrosion change"

The above deficiencies lead to unsatisfactory reproducibility, accuracy and comparability of spot test results