Porous W-10 wt% Ti alloys are prepared by freeze-drying a WO3-TiH2/camphene slurry, using a sintering process. X-ray diffraction analysis of the heat-treated powder in an argon atmosphere shows the WO3 peak of the starting powder and reaction-phase peaks such as WO2.9, WO2, and TiO2 peaks. In contrast, a powder mixture heated in a hydrogen atmosphere is composed of the W and TiW phases. The formation of reaction phases that are dependent on the atmosphere is explained by a thermodynamic consideration of the reduction behavior of WO3 and the dehydrogenation reaction of TiH2. To fabricate a porous W-Ti alloy, the camphene slurry is frozen at -30℃, and pores are generated in the frozen specimens by the sublimation of camphene while drying in air. The green body is hydrogen-reduced and sintered at 1000℃ for 1 h. The sintered sample prepared by freeze-drying the camphene slurry shows large and aligned parallel pores in the camphene growth direction, and small pores in the internal walls of the large pores. The strut between large pores consists of very fine particles with partial necking between them.

The effect of Cu content on hydrogen reduction behavior of ball-milled -CuO nanocomposite powders was investigated. Hydrogen reduction behavior and reduction percent() of nanopowders were characterized by thermogravimetry (TG) and hygrometry measurements. Activation energy for hydrogen reduction of nanopowders with different Cu content was calculated at each heating rate and reduction percent(). The activation energy for reduction of obtained in this study existed in the ranging from 129 to 139 kJ/mol, which was in accordance with the activation energy for powder reduction of conventional micron-sized