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Porous wicks were prepared via powder metallurgy using NH4HCO3 powders as pore-forming agent. The pore-forming agent particle size was varied to control the pore structure and equivalent pore size distribution feature of porous wick. The effect of pore-forming agent particle size on the porosity, pore structures, equivalent pore size distribution and capillary pumping performance were investigated. Results show that with the particle size of pore-forming agent decrease, the green density and the volume shrinkage of the porous wicks gradually increase and the porosity reduces slightly. There are two types of pores inside the porous wick, large-sized prefabricated pores and small-sized gap pores. With the particle size of pore-forming agent decrease, the size of the prefabricated pores becomes smaller and the distribution tends to be uniform. Gap pores and prefabricated pores inside the wick can make up different types of pore channels. The equivalent pore size of wick is closely related to the structure of pore channels. Furthermore, the equivalent pore size distribution of wick shows an obvious double-peak feature when the pore-forming agent particle size is large. With the particle size of pore-forming agent decrease, the two peaks of equivalent pore size distribution approach gradually to each other, resulting in a single-peak feature. Porous wick with single-peak feature equivalent pore size distribution possesses the better capillary pumping performances.

A novel carbon fiber/copper mesh knitted fabric reinforced carbon (Cf/Cu/C) composite was fabricated by a CVI-I/C technique. The mechanical, electrical, arc discharge and tribological properties of the Cf/Cu/C composite were compared with those of a traditional C/Cu composite fabricated by powder metallurgy. The results show that the copper mesh distributes uniformly in the Cf/Cu/C composite, and it exhibits higher mechanical property and more excellent electrical resistivity than those of the C/Cu composite. Meanwhile, the arc resistance property of Cf/Cu/C composite is also better than the C/Cu composite under the same testing conditions. The wear rate is about 80% of the C/Cu composite.

Tin oxide nanowire arrays on titania (001) have been successfully fabricated by chemical vapor deposition of Sn(O t Bu)4 precursor. The morphologies and structures of ordered SnO2 nanowires (NWs) were analyzed by cross-sectional SEM, HR-TEM and AFM. An FIB-tomography technique was applied in order to reconstruct a 3D presentation of ordered SnO2 nanowires. The achieved 3D analysis showed the spatial orientation and angles of ordered SnO2 NWs can be obtained in a one-shot experiment, and the distribution of Au catalysts showed the competition between 1D and 2D growth. The SnO2 nanowire arrays can be potentially used as a diameter- and surface-dependent sensing unit for the detection of gas- and bio-molecules.

Using Ni granules as a catalyzer, composite felts reinforced by both SiC nano-fibers (SiC-NFs) and carbon fibers were prepared at 1273K. SiC-NFs were deposited on the surface of the carbon fibers in-situ by chemical vapor growth. The microstructure and morphology of the fibers after being electroplated and deposited were characterized by scanning electron microscopy and transmission electron microscopy. The phase of the fibers after being deposited was characterized by X-ray diffractometry. The results show that the SiC-NFs produced by chemical vapor growth are single crystals of β-SiC. It was found that Ni catalyzer had important effects on the growth of SiC-NFs. Smaller nano-granules were more active as catalyzers, resulting SiC-NFs appeared more spindle-like and had a more homogeneous dispersion. The weight change of the samples before and after deposition shows that a longer electroplating times results in SiC-NFs having a faster growth velocity.

Aluminium nitride (AlN) nanowhiskers were synthesized on Si substrate by an oxide-assisted vapour transport and condensation method at 900 ◦ C. Electron scanning microscope observations reveal that the whisker-like nanostructured architectures are composed of nanotips growing out from the surfaces of central sphere-like cores. The stem diameter of the nanotip is ∼100 nm and decreases with increasing distance from the core. The formation mechanism of the nanowhiskers is discussed on the basis of structural characterization. It is inferred that Fe2O3 plays an important role in the relatively low temperature growth of the AlN nanowhiskers. The photoluminescence of the nanowhiskers shows a broad blue luminescence band which can be Gaussian divided into three subbands. Spectral examinations and analysis reveal that the three subbands are connected with nitrogen vacancy, oxygen impurity and surface luminescence, respectively. The successful growth of AlN nanowhiskers would provide significant applications in modern optoelectronic and luminescence nanodevices.