Solid State Phenomena Vols. 121-123

Abstract: A novel epoxy/SiO2 hybrid sizing for carbon fiber surface was prepared through sol-gel technique, the structure of the sizing were analyzed, and the effects of the sizing on mechanical properties of carbon fiber composites were also investigated. The analyses by FT-IR and SEM indicated that epoxy/SiO2 hybrid sizing was prepared successfully, SiO2 particles dispersed in the hybrid sizing film homogeneously with nanoscale. The analyses on interlaminar shear strength (ILSS) and impact properties of composites showed that the epoxy/nano-SiO2 hybrid sizing increased ILSS and improved impact properties obviously at the same time.

Abstract: Fe86.5Zr7B3Cu3.5 nanocrystalline ribbon can be directly fabricated by melt – spinning technique with an appropriate quenching speed without annealing processes. The average grain size of α-Fe for Fe86.5Zr7B3Cu3.5 as quenched ribbon prepared with a quenched speed V=40 m/s is about 10-13 nm estimated from X-ray diffraction and TEM observation. For Fe86.5Zr7B3Cu3.5 nanocrystalline as quenched ribbon (V=40m/s), the saturation magnetic induction Bs is 1.47 T, permeability μe at 1 kHz is 25600 and saturation magnetostriction λs is -2×10-6. The magnetoimpedance value Z/Z0 of the Fe86.5Zr7B3Cu3.5 nanocrystalline as quenched ribbon reaches –38.32 % under H=7162 A/m. Our present results reveal a novel route to fabricate the nanocrystaline ribbons with excellent soft magnetic properties and giant magnetoimpedance.

Abstract: In this paper, the electrical properties of NiSi have been characterized using multi capping layer structure for nano CMOS application. We have investigated the formation and thermal stability of Ni silicide using Ni, Ti and TiN capping layers (Ti/Ni/TiN) as a function of Rapid Thermal Processing (RTP) temperature. It was shown that the NiSi with multi capping layer has lower sheet resistances than that with single capping (TiN) layer. NiSi with multi capping layer also showed much better thermal stability. It was verified that the formation Ni-Ti-Si ternary like layer at the top region of thhe NiSi results in improvement of thermal stability.

Abstract: Al-substituted α-Ni(OH)2 was synthesized by a chemical co-precipitation. The as-prepared α-Ni(OH)2 particles were characterized by the means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The obtained α-Ni(OH)2 particles were well crystallized, spherical shape with the particle sizes of 20-35 nm. The electrochemical performance of β-Ni(OH)2 electrode with addition of nanosized α-Ni(OH)2 was investigated by galvanostatic charge-discharge tests. The nanosized α-Ni(OH)2 as additive in the commercial microsized spherical β-Ni(OH)2 electrode improved the discharge capability. As compared to commercial β-Ni(OH)2 electrode, the electrode with nanosized α-Ni(OH)2 exhibited excellent better charge-discharge cycling stability. It may be a promising positive active material for alkaline secondary batteries.

Abstract: To obtain a mass production of nanocrystalline ZnO powders, equipment that combines the conventional self-sustaining combustion process (SCP) with the ultrasonic spraying combustion method (USCM) were applied. The droplet was sprayed into the reaction zone of the furnace to carry out USCM that produces softly agglomerated crystalline ZnO particle with spherical shape. It was confirmed that the ZnO powder was prepared from ultrasonic spraying combustion method having smaller primary particle size, spherical shape with weak agglomeration and larger specific surface area than from conventional self-sustaining combustion method. Synthesized nanocrystalline ZnO powders have primary particle size in a range of 20∼30 nm, and specific surface area of about 20 m2/g under the optimum ultrasonic spray conditions.

Abstract: Synthesis of TiO2 nanocrystals directly from the TiO2 micron powders by the hydrothermal method is reported for the first time. A new route of preparing amorphous TiO2 nanopowders is demonstrated in this paper. The TiO2 nanocrystals phase structure can be controlled by the subsequent treatment with different concentration HCl solutions. When the amorphous TiO2 nanopowders are treated with 0.2M HCl aqueous solution, a spherical anatase phase nanorystals are obtained, while treated with 1.0M HCl aqueous solution, a rod-like rutile phase nanocrystals are formed.

Abstract: Nanocomposite Nd2Fe14B/Fe3B magnetic materials with high performance have been obtained by crystallizing over-quenched ribbons. The effect of addition element of Cu and Zr on the phase component, microstructure and magnetic properties of Nd4.5Fe（76.5-x）B18.5Cu0.5Zrx (x= 0.4, 0.5, 1.5, 2.0, 3.0, 4.0) has been systematically investigated. The average grain size of Nd2Fe14B phase and Fe3B phase for the different compositions were calculated from X-day diffraction pattern, which are in accordance with TEM micrographs. For the Nd4.5Fe77B18.5 ribbons, the average grain size of Nd2Fe14B and Fe3B were 34.2 nm and 51.7 nm, and for the Nd4.5Fe76.3B18.5Cu0.5Zr0.4 ribbons, they were only 36.5 nm and 37.1 nm, respectively. It has been found that the additions of Cu and Zr cause the reduction of the difference of grain size between the hard magnetic phase and the soft magnetic phase, that increase the exchange coupling between them. Therefore, it would lead to the magnetic properties improvement. It has been determined that Nd4.5Fe76.3B18.5Cu0.5Zr0.4 was the optimal composition, and the optimal magnetic properties were: Br= 1.204 T, Hci= 271 kA/m, and (BH)max =111.2 kJ/m3.

Abstract: In order to compensate the force induced deformation of the precision grinding, a piezoelectrically driven micropositioning table is developed to actuate the workpiece for error compensation. To better understand the performance of the micropositioning table, the deformation patterns and stiffness distribution of the micropositioning table under normal grinding force are investigated by computational finite element analysis method. It is noted that the moving part of the micropositioning table can be considered as rigid body and the maximum static stiffness is located at the center of the top surface. The experimental tests are carried out to verify the analysis.