Mullite fibres were synthesised from a mixture of aluminium, aluminium chloride and acidic silica solutions as monophasic salts using a sol-gel technique. The viscosity and rheological behaviour of the mullite precursor sol were examined. Mullite fibres were synthesised using both conventional and microwave sintering techniques. The samples were characterised by X-ray diffraction and scanning electron microscopy. Pure mullite fibres were synthesised by microwave sintering at a relatively low temperature of 1200uC. The grain size of the fibre samples sintered using the microwave technique was finer than that produced by conventional sintering. These results show that microwave sintering is a promising technique for processing mullite fibres.

Hydroxyapatites (HAs) are used as bioceramics for artificial bone substitutes because of their good biocompatibility. In this study, highly transparent ultrafine HA ceramics with a mean grain size of 170 nm were synthesised by spark plasma sintering at 900-10008C and 80 MPa. Phase analysis revealed the presence of a pure HA phase even after sintering at 10008C. The sintered body was almost fully dense (.99%). The total forward transmission was .70% at 400 nm, and it approached the theoretical value of 89% in the infrared wavelength range. The HA ceramics contained several intragranular voids of 5-10 nm. An evaluation of the superplastic flow behaviour of this sintered HA sample at 950-10508C revealed superplasticity with a maximum elongation and initial strain rate of 486% and 1.0x10 24 s 21 respectively at 10008C. The deformed microstructure of HA indicated activated dislocation motion assisted grain boundary sliding to be the major mechanism of superplastic flow with stress exponent values ranging from 4 to 5 based on interface reaction controlled creep. Surprisingly, no dislocations were observed by transmission electron microscopy.

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In the fields of the mechanical micro machining, examples of fabrication and utilization of micro pole or shaft structures with high aspect ratio (AR) by using the micro end-milling process are extremely rare. The micro shaft with high aspect ratio is generally being produced by grinding, turning, wire electro discharge grinding (WEDG), electrical chemical machining (ECM), and so on. Micro pole structures, such as column, rectangular pole, and gear shaft, made by the micro end-milling process, can be utilized in industry. Examples include electrode for electrical discharge machining and micro mold for injection molding. In this research, machining factors and the process were analyzed. Machining experiments of various micro pole configurations were performed. Analysis of the change and effect of the cutting force under the machining conditions was carried out. An analytical study of the deformation of the micro pole caused by the cutting conditions and the cutting force, through the finite element method and ANSYS program, was carried out.

Passivation treatments in NaOH, H 2 SO 4 and HCl were conducted in order to improve the oxidation resistance of Ti 3 SiC 2 at 5008C. The oxidation resistance of Ti 3 SiC 2 passivated in NaOH was the greatest of any treatments due to the formation of an amorphous film during passivation treatment, which became dense, crystalline and seemingly highly protective during oxidation. The detrimental phase transformation of TiO 2 was limited by doping with SiO 2 . Different levels of corrosion happened during passivation treatment in H 2 SO 4 and HCl, which is harmful to oxidation resistance.