The uniform mesoporous SBA-15 consisting of SiO2 with long-range channels Offers an excellent host material to synthesize or assemble the magnetic nanocomposites, such as Fe, Ni. In this paper, highly dispersed and uniform iron nanoparticles were incorporated into the pore channels of SBA-15 through a newly developed strategy in which some kinds of coupling agents were used to entrap the nanoparticles into the silica framework. The X-ray diffraction （XRD）, fourier transmission infrared spectroscopy （FTIR）, high-resolution transmission electronic microscopy （HRTEM） and energy dispersive X-ray spectroscopy （EDX） were performed to further identify the successful incorporation and grafting of iron. Compared with other ordinary non-assembled magnetic nanoparticles, the assembled Fe nanoparticles with the diameter even in the size range of 5～6 nm still have better magnetic properties.
Sixin LI Jiancheng ZHANG Yue SHEN Bo NI Jingang ZHANG
The facile hydrothennal method was used to synthesize Fe3O4 nanoparticles with an average diameter of 1 1nm. The pure body-centered cubic （bcc）-Fe nanoparticles were prepared by reduction of Fe3O4 nanoparticles powder in H2 atmosphere. The structure, morphology and magnetic＇properties of the products were characterized by X-ray powder diffraction （XRD）, transmission electron microscopy （TEM）, thermogravimetric analysis-differential scanning calorimetry （TGA-DSC） and vibrating sample magnetometer （VSM）. The results showed that the as-prepared Fe3O4 nanoparticles had a relatively homogeneous size. The particle diameters became bigger with the increase of reaction time. The growth kinetics of the Fe3O4 nanoparticles was also briefly discussed. The products exhibited superparamagnetic properties at room temperature and the specific saturation magnetization was dependent on the particle sizes.
Glass-ceramics containing β-quartz as a main crystal phase based on the system of SiO2-Al2O3-Li2O-K2O-MgO-ZnO were investigated for the application to magnetic storage substrate for higher storage capacity. Parent glasses were prepared, then nucleated and crystallized at certain temperatures for 3-4 h. The crystallization kinetics of glass-ceramics was also studied. The grain size was estimated by Scherrer formula and image treatment of transmission electron microscopy （TEM）. The results showed that the Avrami exponent was determined to be 3.88, the activation energy 189.3＋7 k J/tool and the grain size 30-60 nm. A detailed microstructure of the glass-ceramics, including grain distribution and the morphology of nano-crystalline was characterized by TEM, X-ray diffraction （XRD）, differential scanning calorimeter （DSC）, differential thermal analysis （DTA）. The relationship between microstructure and mechanical properties was also discussed.
Shengyu JIANG Jiancheng ZHANG Feng GU Yue SHEN Hua WANG
Powders of hexagonal-structured single-crystalline nickel sulfide nanorods have been synthesized in cetyltrimethy ammonium bromide （CTAB）/water/hexane/n-pentanol quaternary microemulsion under hydrothermal conditions by using the reaction of carbamide and carbon disulfide as a sulfide source. Single-crystalline nickel nanorods have been synthesized via thermal decomposition by using single-crystalline nickel sulfide nanorods as precursor. The influence of different reaction parameters on the morphology of the products has been investigated. The structure, morphology and magnetic properties of the products were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM）, calorimeter （TGA-DSC） and vibrating sample magnetometer showed that the specific saturation magnetization （σs） and 37.5 emu/g and 68.50e, respectively. thermogravimetric analysis-differential scanning （VSM）. The results of coercivity values （Hc） magnetic measurements of nickel nanorods were
Yu LUO Jiancheng ZHANG Yue SHEN Shutao JIANG Guoyong LIU
