Corrosion behavior of high-level waste container materials Ti and Ti-Pd alloy under long-term gamma irradiation in Beishan groundwater

Titanium and titanium-palladium alloys are important potential materials for nuclear waste container,which will endure both intenseγ-irradiation and groundwater erosion.Therefore,it is very important to investigate the corrosion behavior of the container materials.In this research,the cumulative dose effect of TA8-1 type titanium-palladium alloy(TA8-1)and TA2-type pure titanium(TA2)underγ-irradiation was studied based on the geological disposal of nuclear wastes.The irradiation experiments were performed at room temperature using^(60)Co gamma sources with a 5.0-kGy·h^(-1)intensity for 40,80 or 160 days,respectively.The pH value and conductivity of Beishan groundwater were investigated.The results showed that the pH value changed from alkaline(8.22)to acidic(2.46 for TA8-1 and 2.44 for TA2),while the un-irradiated solution remained alkaline(8.17 for TA8-1 and 8.20 for TA2)after 160 days.With the increase of irradiation dose,the conductivity increases rapidly and then tends to become stable,which indicates that the titanium dioxide corrosion layer formed on the surface of the sample surface effectively prevents further corrosion.Meanwhile,XRD and SEM-EDS analysis results show that the main components of corrosion products are TiO_(2) and TiO.The titanium on the surface of the sample is oxidized,resulting in slight uneven local corrosion.The results show that TA8-1 and TA2 are suitable to be used as candidate materials for high-level waste(HLW)disposal containers due to their excellent performance under long-term and high-dose irradiation corrosion.

Mitigation of hydrogen permeation into steel by bacteria:a new research proposal

A new research proposal was introduced aiming at solving the fundamental theory for reducing the risk of hydrogen embrittlement(HE)in high-strength steels by utilizing hydrogen-consuming microorganisms.The superior performance of high-strength steel can meet the material strength requirements for remote deep-sea marine engineering development.Due to the heavy corrosive marine environment,steel structures must be protected by cathodic protection.However,high-strength steel is sensitive to stress corrosion cracking and HE,and cathodic protection can promote hydrogen permeation into steel.Hydrogen-consuming microorganisms are widespread in the natural environment and they utilize the energy of hydrogen oxidation to survive.If we could make use of the hydrogen-consuming function of microorganisms to consume the hydrogen generated during the cathodic protection process,then the potential for cathodic protection can be reasonably lowered,ideally protecting the steel and simultaneously reducing the possibility of HE.

Double layered superhydrophobic PDMS-Candle soot coating with durable corrosion resistance and thermal-mechanical robustness

Nature-inspired superhydrophobic coatings with typical Cassie-Baxter contacts garner numerous interests for multifunctional applications.However,undesirable poor mechanical and thermal stability are still crucial bottlenecks for real-world employment.This work introduces a cost-effective,fluorine free and versatile strategy to achieve double-layered PDMS agglutinated candle soot coating with superior water-repellent superhydrophobicity.The surface morphologies,chemical compositions and wettability behaviors were investigated in detail.The mechanical stability,chemical stability and durable corrosion resistance of the fabricated PDMS-CS coating were evaluated through friction,calcination and electrochemical impedance spectroscopy.The results demonstrate a remarkably enhanced mechanical robustness and corrosion resistance,indicating PDMS units can act as an effective agglutinating agent between candle soot and underlying substrate.The synergistic effect of PDMS agglutination,porous network nanostructures and extremely low surface energy of incomplete combustion induced candle soot deposition contribute to the eventually robust corrosion resisting coating,which greatly increases the possibility for practical applications.