Compositionally Graded Microstructure for Ag-Fe Nanoparticles

Ag-Fe nanoparticles with a highly Ag rich average composition were synthesized by the sonochemical route.Silver-iron system exhibits a wide miscibility gap in the bulk materials.Interestingly,a graded compositional profile along the nanoparticle radius was observed.Regions at and near the surface of the nanoparticle contained both Ag and Fe atoms.The composition got relatively deficient Fe towards the center of the particle with particle core made up of pure Ag.Alloying of Ag and Fe is confirmed by the absence of diffraction signal corresponding to pure Fe phase and presence of a paramagnetic phase in nanoparticles containing a diamagnetic(Ag)and ferromagnetic(Fe)elements.

锌-氧化石墨烯复合涂层的微观结构与腐蚀性能

石墨烯由于高的渗透性和化学惰性已表现出作为防腐蚀材料的潜力,但是尚有一些问题待解决。首先,用于大型结构或者大面积涂装时,石墨烯缺陷部位由于抗渗透性的丧失,形成了类电池效应,局部增强了腐蚀效果,因此需要开发经济且实用连续的大面积石墨烯片的方法。其次,片状石墨烯在底材上的转变以及之后长期的转变过程和附着力的保持是要解决的另一个问题。