Papers by Author: Xiang Rong Zhu

Abstract: TiO2 films were deposited on AZ31 magnesium alloy substrates by r.f. magnetron sputtering. The corrosion behaviors in simulated body fluid (SBF) of the film samples were investigated and compared to the bare AZ31 magnesium alloy. After 3 days’ corrosion in SBF, only part of the TiO2 layer suffered from corrosion and the substrate was prevented from corrosion. In contrast, the bare magnesium alloy suffered from severe corrosion. After 10 days’ corrosion, the TiO2 layer was penetrated and the substrates still did not suffer from corrosion. After 15 days’ corrosion, besides TiO2 layer, the substrate suffered from corrosion to some degree. The depth of the corrosion layer is about 6 m, which is far lower than that of bare magnesium alloy, 40 m. The results show that TiO2 films effectively improve the corrosion properties of magnesium alloys.

Abstract: The morphology of typical carbon materials including granular graphite, carbon nanotubes and graphenes was observe by scanning probe microscope (SPM). When water is used as the dispersants for preparing observing samples of the above carbon materials, the typical morphology characteristics of spherical graphite, curved carbon nanotubes and graphene sheets are distinctly exhibited by SPM. However, for graphene materials, when alcohol or dimethylformamide (DMF) is used as dispersants, the quality of SPM images becomes poor. The interaction between the dispersants and materials should be responsible for these observation results.

Abstract: Controlled grafting of S-1-(1-naphthyl) Ethylamine-imprinting polymer layer on the silica-gel was carried out by the surface-initiated atom transfer radical polymerization (ATRP). Polymerization time was used as the independent variable to manipulate the amount of grafted imprinting polymer on the silica-gel. For comparison, molecularly imprinted polymers (MIPs) without silica-gel also prepared at the same condition. SEM, FT-IR and UV spectrum were used to study the structural morphology and selectivity of polymers and probe the incorporation of imprinted polymer layer on the surface of substrates. Results indicate that the integration of ATRP and molecularly imprinted polymerization realize preparation of molecular selective polymers and it is possible to tune selectivity and morphology in rational way by changing polymerization times. Meanwhile, we achieve a reference strategy for the development of molecularly imprinting polymer for drugs and to handle forms in certain applications such as chromatographic stationary phases for chiral separations.

Abstract: TiN films were deposited on the AZ 31 magnesium alloy substrates by d.c. magnetron sputtering technique. The surface properties of the films were investigated. The scanning electronic microscope observations reveal the dense structure characteristics of as-deposited TiN films. Under 200°C heat treatment for 30 minutes or 4 times’ heat cycles at 85°C for one hour, no structural defects such as cracks are observed on the surface of the films. Adhesion experiment further demonstrates the stability of the film and the strong combination between the film and the substrate. Nano-indentation experiment shows that the average micro-hardness of TiN film reaches 23.85 Gpa. Finally, the corrosion experiments in simulated body fluid initially reveal the degradation property of TiN film.

Abstract: NixZn1-xFe2O4 (x=0.4, 0.6) powders are synthesized by sol-gel technique. The X-ray diffraction (XRD) measurements show their polycrystalline spinel structural characteristics. Both XRD and Atomic Force Microscopy demonstrate the samples are nanosized. At room temperature typical soft magnetism is exhibited by the samples. The reflection attenuation resulting from microwave absorption would reach to 1.9 dBm over the frequency range 6 GHz - 10 GHz when the samples are paved on a 10 cm  10 cm square aluminum plate with a thickness of about 0.35 mm.