Materials Science Forum Vols. 486-487

Abstract: Nanosized ITO(indium tin oxide) powders were prepared in ethylene glycol solution under mild temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. The average size and distribution of the synthesized ITO powders were about 20 ㎚ and broad, respectively. The phase of synthesized particles was crystalline reacted at 230 0C for 6 h.. The optical properties of the synthesized ITO powders were transparent.

Abstract: This paper descirbes the characteristics of gold films prepared by a hybrid plasma based an ion implantation/deposition (PBIID) system. The surface morphology and structure of the film were affected by the voltage applied to the target. With increasing negative voltage, the surface became thinner with a lesser number of nuclei. The grain structure varied from the continuous film at 0 kV to the channel at -1 kV, and further to the islands (mounds) at -5 kV. The ions in the sheath are believed to play an important role in the deposition of the film.

Abstract: The aim of this study is to report results of initial trials involving the strip casting process for ETPC (Electrolytic Tough Pitch Copper) and to investigate the effect of process parameters on the chemistry, microstructure evolution and mechanical properties of ETPC. A vertical twin roll strip caster used in this research was designed for manufacturing high-purity and/or reactive metal strips with a system for controlled atmosphere ranging from 103 to 10-3torr. It is expected that oxygen content can be reduced as low as 0.001wt% in as-cast strip.

Abstract: Carbon and boron were mainly considered to strengthen grain boundaries formed during single crystal casting of complex shaped components. However, those elements cause segregation forming the phase with low melting temperature or with brittle nature. To determine the optimum amount of these elements, the effect of boron on solidification behavior was investigated in the C doped single crystal RR 2072 alloy. The solid/liquid interface morphologies and the solidification microstructures were studied at various solidification rates and with B addition by directional solidification.

Abstract: Aluminum foam with 0.2 g/cm3 density showed a good sound absorption property at frequencies higher than 2000 Hz. Compressed aluminum foam with an air gap of 50 mm or higher exhibited a very high sound absorption property near 400 Hz.

Abstract: The uniaxial compressive test results of several aluminum foams are compared with aluminum alloy and ppi (pore per inch) of open cell foam. The compressive stress-strain curve of aluminum alloy foams exhibits universal three deformation regions: an initial linear elastic response, and then extended plateau region with a nearly constant flow stress, a final densification as collapsed cells are compacted together. The lower the foam densities are, the longer the plateau region is, but lower densities also imply lower yield stress.

Abstract: Cordierite was synthesized by the reaction sintering using a high-energy ball milling process. After a high-energy ball milling for 32hr, the reaction temperature of cordierite was reduced to 1350oC from the conventional synthesis temperature of 1460oC. High-energy ball milling process was effective for the formation of amorphous silica layer to provide a low reaction temperature of cordierite.