What are the characteristics of corrosion of metal by irradiation lines?
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Combined with the background of metal corrosion caused by irradiation lines discussed previously, metal corrosion caused by irradiation lines has the following core characteristics: Microscopic defects drive corrosion acceleration: High-energy irradiation will produce a large number of point defects, dislocation rings and cavities inside the metal, providing channels for the migration of corrosive medium ions, greatly increasing the corrosion reaction rate, and the corrosion resistance of most metals will be significantly reduced. Corrosion behavior exists in both directions: Irradiation can accelerate the uniform corrosion of metals. At the same time, under certain conditions (such as aluminum in a solution containing chloride ions), it will slow down pitting corrosion. It is not a single corrosion aggravation effect. Irradiation promotes stress corrosion cracking: The segregation of grain boundary elements caused by irradiation (such as chromium depletion in the grain boundaries of stainless steel) will greatly increase the intergranular corrosion sensitivity of metals, and radiation-induced stress corrosion cracking (IASCC) will easily occur under the synergistic effect of stress. Great differences in sensitivity between metals: Uranium alloys, ordinary carbon steel, etc. are extremely sensitive to radiation corrosion, and the corrosion rate can be increased a thousand times. ； Tungsten, nickel-based alloys and other alloys have excellent radiation resistance and have minimal increase in corrosion rate. multi-effect synergy: Irradiation will simultaneously induce radiation oxidation, radiation facilitation and other effects, change the chemical reaction balance of the corrosive medium, and further amplify the corrosion damage effect. Performance degradation is dose-dependent: The higher the irradiation dose and the longer the exposure time, the more significant the corrosion performance degradation of the metal. Radiation hardening, helium embrittlement and other phenomena will cause synergistic destructive effects with corrosion.
The author's summary is very good, especially the two points of accelerated corrosion of microscopic defects and bidirectionality, which are indeed critical in the field of nuclear materials. I have seen some experimental data before. The greater the amount of irradiation, the higher the dislocation density, and the corrosion rate can increase several times. However, I would like to ask the original poster. You mentioned that irradiation of aluminum in a chloride ion solution slows down pitting corrosion. Is this phenomenon related to the thickening of the surface oxide film caused by irradiation, or does the defect change the local electrochemical environment? Is there any specific working condition parameter reference? After all, the results may vary greatly under different dosages and temperatures, and practical applications need to be evaluated based on specific circumstances.