CHEMICAL VAPOR TRANSPORT PROCESS IN HYDROGEN REDUCTION OF BALL-MILLED MOLYBDENUM AND TUNGSTEN OXIDE POWDERS

Chemical vapor transport of ball-milled MoO 3 and WO 3 powders in a non-isothermal hydrogen reduction process was discussed in terms of the sizes and specific surface area of oxide particles. Although all reduction processes were completed at nearly the same tempera- ture, they became stepwise with lower starting temperatures and peak points of each sequence due to the refinement of the oxide particles. In particular, the chemical vapor transport process in the reduction of MoO 3 (MoO 3 � MoO 2 ) was strongly affected by the initial states of the oxide powders.