Study On Preparation And Properties Of Surface Corrosive Self-brittle Decontaminant For Iron-based Materials

In the nuclear industry,metal materials,especially iron-based metal materials?such as carbon steel,stainless steel?are widely used in various production processes,which leads to the production of a mass of contaminated iron-based metal materials along with the maintenance and decommissioning of the nuclear equipment.It is reported in the literature that radioactive contamination is generally distributed in the surface of the metal within a few tens of micrometers,thus it is necessary to destroy the surface of the metal in the decontamination process.The self-brittle decontamination is a novel radioactive decontamination method which produces less secondary contaminants and can be operated remotely.It is a pity that self-brittle decontamination is not suitable for corrosive decontamination of metal surfaces,which due to that it can only remove loose contaminants on the surface,and the self-brittle detergent prepared by the polymer has poor corrosion resistance.The inorganic powder has excellent stability in the acid-base environment,therefore it can improve the corrosion resistance of the self-brittle detergent.In this paper,we prepared an iron-based metal surface corrosive self-brittle detergent,which was combined with inorganic powder to improve the corrosion resistance of the self-brittle detergent base,and then studied its properties.The SiO₂/P?MMA-co-MAA?composite self-brittle detergent was prepared by compounding self-regulating P?MMA-co-MAA?with SiO₂ which was modified by a silane coupling agent.The modified SiO₂ and the composite were characterized by FTIR and TG,the results showed that SiO₂ was successfully modified by KH550,and the amino groups grafted on the surface of SiO₂ formed hydrogen bond with the side groups of P?MMA-co-MAA?,which makes the composite detergent has good film-forming and self-brittle properties and can adjust the viscosity of the detergent.The self-brittle properties of the detergent were studied,it was found that the detergent chips could be regulated by adjusting the particle size of SiO₂,and the regulation mechanism was explained accordingly.The detergent performed admirable decontamination performance,and the average decontamination rate reached98.48%.For the different corrosion resistance of carbon steel and stainless steel,a series of self-brittle corrosive detergents were prepared by adding corrosive components?such as nitric acid?to the prefabricated composite detergent,and the self-brittle properties of the detergent remained the same.Firstly,the effects of nitric acid and borax inhibitor on the corrosion of carbon steel by detergent were studied by electrochemical measurement technology,it's indicated that when the concentration of nitric acid was 0.5 mol/L and the concentration of borax was 0.01 mol/L,it can produce good corrosion effect on carbon steel.Then,the effects of nitric acid,ferric chloride and sodium chloride on the corrosion of stainless steel by detergent were investigated,the results showed that the concentration of nitric acid was 1mol/L,and the concentration of ferric chloride was above 0.02 mol/L could produce good corrosion effect on 304 stainless steel,while the concentration of ferric chloride was above0.09 mol/L could produce good corrosion effect on 316L stainless steel.In addition,the detergent could produce a better corrosive effect by increasing the Cl^-concentration by adding sodium chloride.Finally,the corrosion performance of the detergent was tested.The macroscopic and microscopic morphology after corrosion showed that the detergent produced uniform corrosion on the metal surface.The corrosion depth of the detergent on carbon steel,304 and 316L stainless steel could reach 2.9³.8?m,2.8³.8?m and 2.1².6?m,respectively.