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The utilization of alumina based ceramics has increased in our country. Alumina must have some specific characteristics for production of advanced ceramics. Physical and chemical propertes of Seydişehir alumina make it non-ceramic grade raw materials. The aim of this study is to find out process conditions for production injection moulded ceramics from Seydişehir alumina powders. This study essentially consists of characterisation, improvements of properties, injection moulding and sintering. X-ray diffraction analysis, water absorption, apparent porosity, bulk density and three point bending tests were applied to the sintered samples Physical properties of the products were greatly affected by sintering temperature

In general high Q is a desired property for transducer applications, which is the indication low loss. However for the underwater acoustic applications wide bandwidth is also a desired property. Therefore the Q values should be low to achieve wide bandwidth. Cymbal transducer has the highest figure of merit as a hydrophone and as well as huge potential for underwater projector applications. However Q of the standard cymbal transducer is higher than desired and it is a disadvantage of this transducer. In this investigation cavity beneath the endcaps of the cymbal transducer were partially filled with polymeric media to cause visco-elastic damping. All the experiments were performed with ANSYS FEM codes in air. Initial results showed that the Q of the cymbal transducer can be tuned to the desired value by filling the cavity with beneath the endcaps.

CoWB based composites were produced by annealing Ni33.6Co23.2Zr0.5Ta4W23.7B15 bulk metallic glass above the crystallization temperature. The effect of annealing on the microstructure of the composites was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Microhardness (Hv) and indentation fracture toughness (KC) of the composites were also measured. Microstructural examinations revealed that the first precipitated phase as a result of annealing is a nickel solid solution. As the annealing time is increased, the CoWB and the nickel solid solution begins to precipitate. If the annealing time is increased further, the CoWB remains stable, while the nickel solid solution transforms into the Ni3Ta. The microhardness of the as-cast alloy was determined to be 1190 HV. As a result of annealing, composites with a microhardness of around 1400 HV were obtained due to the precipitation of CoWB. KC of the composite with the maximum hardness was determined to be ~3 MPa.m1/2. The effect of microstructure on the mechanical properties of the composites is discussed.