MgB 2 bulks were successfully prepared by Cu-doping sintering at 575 • C for only 5 h, exhibiting an obvious decrease in the sintering time at low temperature. According to the thermal analysis, the local Mg-Cu liquid formed first during the sintering process and then provided higher transport than the solid for the diffusion of Mg atoms into B, resulting in an accelerated reaction between Mg and B. The measured critical current density (J c ) of all the doped (Mg 1.1 B 2 ) 1−x Cu x (x < 0.10) samples was 1 × 10 6 A cm −2 in zero field at 20 K and about 1 × 10 5 A cm −2 in 2 T field at 20 K, respectively. The excellent J c is mainly attributed to the grain-boundary pinning mechanism resulting from the formation of small MgB 2 grains during the low-temperature sintering. Further, we found that with increasing the amount of Cu addition in the low-temperature sintered MgB 2 samples, the predominant flux pinning mechanism of the doped sample varies from grain-boundary pinning to MgCu 2 -nanoinclusion pinning introduced by the reaction between Mg 2 Cu and residual B. This transition results in an abnormal increase of J c in the sintered (Mg 1.1 B 2 ) 0.90 Cu 0.10 sample compared to the sintered (Mg 1.1 B 2 ) 0.95 Cu 0.05 sample in which only Mg 2 Cu was found around the edge of voids.

The effect of microstructure variation on the corrosion behavior of high-strength low-alloy (HSLA) steel was investigated. The protective property of the corrosion product layer was also explored. Experimental results reveal that the type of microstructure has significant effect on the corrosion resistance of HSLA steel. The measurement results of weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy indicate that the steel with acicular ferrite microstructure exhibits the lowest corrosion rate. Martensite exhibits a reduced corrosion resistance compared with polygonal ferrite. It is found that the surface of the acicular ferrite specimen uniformly covered by corrosion products is seemingly denser and more compact than those of the other two microstructures, and can provide some amount of protection to the steel; thus, the charge transfer resistance and modulus values of the acicular ferrite specimen are the largest. However, corrosion products on martensite and polygonal ferrite are generally loose, porous, and defective, and can provide minor protectiveness; thus, the charge transfer resistance values for polygonal ferrite and martensite are lower.

In present work, two conductive filler (carbon fiber with Nickel (Ni) coatings and carbon fiber with Nickel/Fe3O4 nanoparticle (Ni/Fe3O4-NPs) composite coatings) were prepared by electrodeposition. Microstructure observation indicated that the coatings were deposited uniformly on the surface of fiber. Vibrating sample magnetometer (VSM) and electromagnetic interference (EMI) shielding test showed that the two conductive filler has good saturation magnetization and EMI shielding effectiveness.The conductive filler of carbon fiber with Ni/Fe3O4-NPs composite coatings was more excellent. They are promising for application in electromagnetic shielding materials.

In order to prepare bioactive hydroxyapatite (Ca10 (PO4)6(OH) 2, HA) coating with ideal biocompatibility, the surface of titanium alloy was treated with the two kinds of chemical methods, which are the acid-alkali-combination method and Self-polymerization-adhesion of dopamine. After pretreatment, the treated titanium alloy plates were immersed in simulated body fluid (SBF) to form HA coating on their surface. The chemical composition of the coating was analyzed by an X-ray diffraction (XRD) and the morphology was observed by a scanning electron microscope (SEM). After that, the plates were training in vitro cytotoxicity test with MC3T3-E1 osteoblasts. Compared with the results of cell culture, the method of Self- polymerization -adhesion of dopamine showed better cell adhesion and proliferation..

With sugar as an addition, the active carbon released from sugar can lead to the effective carbon doping in MgB2 superconductors only under the condition of high temperature sintering. However, this kind of carbon doping cannot occur at low temperature sintering condition. The reason is that the carbon released from the decomposition reaction of the sugar added in MgB2 has very low chemical activity during low temperature sintering process, which is similar with the results of elemental carbon or graphite doping directly. Thus, only the sintering temperature reaches a certain temperature or more (generally greater than 700oC), the carbon can possess sufficiently high chemical activity and go into the lattice of MgB2 to replace the B. In the condition of low temperature, it is difficult to form an effective carbon-doped.