Junchao TAO
,
Yue SHEN
,
Feng GU
,
Jinzhuan ZHU
,
Jiancheng ZHANG
材料科学技术（英文）
Well-organized mesoporous titania particles and thin films were successfully synthesized by using tetrabutyl titanate as the inorganic precursor and triblock copolymer (Pluronic P123) as the template via evaporationinduced self-assembly process. The resulting materials were characterized by high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD). Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and atomic force microscopy (AFM). Macro shape of mesoporous titania would greatly influence the mesostructure of materials, and the probable reasons were also discussed.
关键词:
mesoporous titania
,
null
,
null
,
null
,
null
,
null
,
null
Ruwei GAO
,
Wei CHEN
,
Jiancheng ZHANG
,
Weicun FONG
,
Wei LI
,
Xiumei LI
材料科学技术（英文）
For both sintered and nanocomposite NdFeB magnets, deltaM(H) of the Henkel plot increases from zero, and reaches a peak, then decreases and changes to the negative values with increasing applied field. This shows that the intergrain interaction changes from the exchange-coup ling type into the magnetostatic interaction type. The magnetic field corresponding to the peak of deltaM(H) is slightly smaller than the coercivity of magnet. The peak of deltaM(H) for aligned sintered magnet is greater than that for misaligned magnet. deltaM(H) peak of the nanocomposite NdFeB magnets increases with decreasing grain sizes. It indicates that the effect of alignment field on the properties of magnet is similar to that of exchange-coupling interaction.
关键词:
Ruwei GAO
,
Jiancheng ZHANG
,
Xianhong DENG
,
Yongjun ZHANG
材料科学技术（英文）
The demagnetization process and the coercivity mechanism for anisotropic HDDR Nd(Fe,Co)B bonded magnets were studied by comparing the dependence of coercivity on the alignment field applied while the powders were pressed. The results showed that both the remanence and the coercivity of magnet increased with increasing alignment field. The demagnetization process of the magnet can be classified as the nucleation process inside the grains and the domain-wall motion between the grains. The combined effect of two processes determines the coercivity of HDDR NdFeB bonded magnets.
关键词:
Shengyu JIANG
,
Jiancheng ZHANG
,
Feng GU
,
Yue SHEN
,
Hua WANG
材料科学技术（英文）
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 π showed that the Avrami exponent was determined to be 3.88, the activation energy 189±7 kJ/mol 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.
关键词:
Glass-ceramics
,
动力学
,
磁盘基片
