Preparation And Properties Of Nanostructures On The Surface Of Carbon And Silicon Carbide

Carbon and carbon-based materials have been the hotpot of research for a long time because of their excellent mechanical properties,electrical properties,chemical stability and high temperature resistance.It has been successfully applied to many fields,such as optoelectronic devices,ion batteries,aviation,and nuclear energy.This study based on carbon and silicon carbide which have important applications in nuclear energy.Graphite and silicon carbide can be used as moderator,reflector and core components in molten salt reactor.During the operation of the reactor,the structural materials are confronted with harsh working conditions such as high temperature,strong neutron irradiation and strong corrosion.In addition,with the rapid development of nanotechnology,some nanomaterials have been found to have excellent creep resistance,fatigue resistance,irradiation resistance,corrosion resistance and other unique properties.Therefore,the research on the combination of nanomaterials and nuclear energy materials has attached great interest of researchers.Based on graphite and silicon carbide materials,this study proposed new methods to prepare nanostructures on the surface by ion beam irradiation technique and high temperature molten salt technique,and further study on its electrical properties,mechanical properties,etc.It provides important research value for the potential applications of carbon based materials with new nanostructures in various fields.The research results of this study show that:1.Through the swelling effect of 4H-Si C material after ion beam irradiation,the micro-nano structure can be fabricated on the surface of 4H-Si C with assiatant of a mask.The height of micro-nano structures can be regulated from?1 nm to?251 nm through ion beam irradiation energy,dose,and ion species.The horizontal size can be regulated from tens of nanometers to centimeters through the template.Under the condition of low-energy ion irradiation,the swelling on the surface of 4H-Si C material is mainly due to the aggregation of interstitial atoms between the crystal planes,causing the lattice swelling of the material;the swelling under high-energy ion irradiation is mainly Due to the amorphization of the material after irradiation,the density of the material changes and swelling occurs.2.The contact angle of 4H-Si C materials with size of?400 nm nanostructures on the surface increased from 33°to 64°.The surface potential of the irradiated 4H-Si C decreases with the increase of the dose and then increases to the initial level.The surface potential of the 4H-Si C materials can be regulated from 0 m V to-126.6 m V by ion beam irradiation.And the optical properties of the irradiated 4H-Si C surface also changed after ion irradiation.The reflectance of the irradiated region is higher than that of the unirradiated region under the infrared light with a wavelength of 3.184?m,while that of the irradiated region under the infrared light with a wavelength of 10.432?m is lower than that of the unirradiated region,which has potential applications for the new discovery of 4H-Si C in semiconductor devices,metamaterials and other fields.The study on the mechanical properties of 4H-Si C after ion beam irradiation show that the hardness and Young's modulus decreased after ion irradiation,but it tends to saturation as the irradiation dose increased,and the saturated 4H-Si C were 24.9±0.3 GPa and298.1±8.2 GPa,which still has good mechanical properties.3.There was no obvious swelling effect of highly oriented pyrolytic graphite after ion beam irradiation.The graphite layer with a thickness of 178.3±4.7 nm on the surface was destroyed,many cracks were formed and the inner layer of graphite was exposed.There are many small dendritic protrusions with height of?34.1 nm on the outer surface,and the Young's modulus of the small protrusions increases.4.Through high temperature molten salt technology,Na NO₃ nanoparticles were prepared on the surface of the highly oriented pyrolytic graphite surface,with the size of<10 nm,which is very hard to formed in current study hard.It provided a universal method to prepare salt nanoparticles,prepare the relatively stable nanostructures on the graphite surface,and provides more direction in the potential application of salt particles provide.In the study of the interaction between graphite and molten salt,it is found that the interaction between salt particles and the surface of highly oriented pyrolytic graphite is closely related to the environmental humidity.