Papers by Author: Xiang Hua Kong

Abstract: Now insulation films are often prepared by smooth rubberroll on the surface of non-oriented silicon steel sheet. Though the surface resistance is enough high to ensure the quality, it will dramatically decrease after stress relief annealing. In order to understand the related mechanism, the film’s microstructure was characterized by SEM. The results show that the main composition of semi-inorganic coating is Cr, Mg C and O, in which C come from the organic polymer. According to the composition, the insulation film can be divided into two parts, the outer one is organic polymer and the inner one is chromate. The main reason for the unstable surface resistance is that the coating in the thickness direction is not uniformity.

Abstract: MgO-PSZ tubes used in metallurgical oxygen sensors were prepared by powder injection molding process. The microstructure was characterized by SEM, XRD and Thermomechanical Analyzer. The sintered tubes were assembled into oxygen sensors and tested in RH vessel. SEM images demonstrated that there were few pores in the tubes. The optimum injection pressure for the present organic binder is 20~30 MPa. XRD demonstrated that cubic, tetragonal, and monoclinic phase coexisted in the tube and the main phase is monoclinic phase. The results show a few monoclinic phase should be helpful for the thermal shock resistance. The thermal shock resistance of MgO-PSZ tubes was enough to determinate the active oxygen concentration in the steel melt.

Abstract: In this paper the influence of carbon nanotubes (CNTs) on anticorrosion properties was discussed. KMnO4 modified carbon nanotubes were added into Waterborne PolyUrethane, then galvanized steel sheets were dipped into this composites to get a thin film and dried at 120 °C for 60 seconds. SEM observation show the film thickness was 3 µm and CNTs were dispersed in the polymer matrix. XRD demonstrated that some KMnO4 decomposed into K2MnO4 and MnO2. Polarization curves demonstrated the film exhibited excellent anticorrosion when the amount of KMnO4 modified CNTs was 6%.