The Surface Modification, Characterization And Properties Of Ni-based Nanocomposite Particles

The surface coated composite nanoparticles are the research hotspot in the Materials Science field. The appropriate coating materials can not only prevent the nanoparticles from oxidizing, but also can provide the surface of nanoparticles with more functional groups, solve agglomeration in the polymer and the poor compatibility with organic substance. Accordingly, modification can improve the physical chemistry performance and enlarge the application range of nanoparticles.The main purpose of this dissertation is the modification of nano-Ni, as well as the characterization and performance analysis of the composite nanoparticles. The aim is: First, an organic or inorganic surface coating will be formed in the surface of nanoparticles. This can avoid contacting between nano-Ni and air. It can improve the oxidation resistance of nano-Ni. Second, the surface coating possesses well electric or dielectric character which makes the composite nanoparticles can be used in the field of microwave absorption materials or electrorheological fluids. The research details included as following:1. The surface of nano-Ni was modified by silane coupling agents (KH-550). The IR results show that silane coupling agents and nano-Ni were combined through chemical bond. There is -NH₂ group in the surface of nano-Ni which provides active point for the polymerization of aniline. The electromagnetic parameters of modified nanoparticles were measured. Then the electromagnetic performance of the composite particles was analyzed. The reflection loss R (dB) of the composite particles was simulated with the electromagnetic data. Nano-Ni/PANi composite nanoparticles were prepared through in situ polymerization of aniline in the presence of APS-nanoNi. The -NH2 group took part in the reaction through analysis of composite nanoparticles. The PANi coating improve particle's oxidation resistance in air and compatibility with polymer body. The composite nanoparticles have core-shell structure.2. The surface of Nano-Ni was coated with dielectric silica via liquid deposition method and Ag via the inverse microemulsion method. Subsequently the charater of the composite nanoparticles was analyzed. According to the IR and TEM results, we can conclude there is an inorganic coating in the particles' surface. The oxidation resistance in air and magnetic property of composite nanoparticles were characterized by the thermo and VSM result.