Papers by Author: Dae Gun Kim

Abstract: The effect of Cu on the hydrogen reduction of molybdenum oxide powders was investigated by measuring the humidity change during a non-isothermal process of hydrogen reduction. The presence of Cu induced a shift in the reduction temperature and strongly affected the reduction processes of MoO3→Mo4O11→MoO2, which comprised the contained chemical vapor transport of MoOx(OH)2. This study suggests that the surface of the Cu grains acts as a nucleation site for the reduction of MoOx(OH)2 to MoO2 particles from MoO3 or Mo4O11 phases. Such an activated reduction process results in the deposition of metallic Mo and MoO2 particles on the surface of the Cu grains.

Abstract: The sintered microstructure homogeneity of W-15wt%Cu nanocomposite powders prepared from W-CuO mixture was investigated. The increment of heating rate considerably affected the homogeneity of sintered microstructure. In case of the higher heating rate, the microstructure was more homogeneous than that of the lower heating rate by reason of Cu- exudation during heating-up process.