The conducting polyaniline （PANI） prepared by three chemical oxidative polymerization pathways including microemulsion, emulsion and aqueous solution methods were studied and compared. Their structures, morphologies and properties were characterized using FT-IR, XRD, TEM and TGA. PANI particles formed in aqueous solution have a smallest size and doping HCl enables to increase their conductivity. In contrast, PANI particles prepared by emulsion method have the highest thermal stability and conductivity and more ordered morphology. Rather different from these two methods, microemulsion approach allows forming nanocomposite PANI with tube-like nanostructure.
The effects of an applied magnetic field on the corrosion process of beryllium copper in NaCl solution have been investigated by electrochemical measurements, scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. The results showed that a horizontal magnetic field with 0.4 T barely shifted the open circuit potentials （Ecorr） of beryllium copper in NaCl solution with different concentrations. However, the horizontal magnetic field increased the limiting current density of beryllium copper in NaCl solution with low concentration, while decreased the limiting current density of beryllium copper in NaCl solution with high concentration. It was found that magnetic field accelerated the diffusion of CuCl2- away from the electrode surface and delayed the formation of Cu2O. The results of SEM and EDS showed that the inffuence of magnetic field over the elements distribution of the corrosion products differed from the different concentration of the immersion solution.
Jing Hu, Chaofang Dong, Xiaogang Li and Kui Xiao Corrosion & Protection Center, University of Science and Technology Beijing, Key Laboratory for Corrosion and Protection of Ministry of Education, Beijing 100083, China
